Carbohydrate Research 402 (2015) 215–224

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Halogenated D-xylono-d-lactams: synthesis and enzyme inhibition study Naresh Bhuma a, , Madhuri Vangala a, , Roopa J. Nair b, Sushma G. Sabharwal b, Dilip D. Dhavale a,⇑ a b

Department of Chemistry, Garware Research Centre, University of Pune, Pune 411007, India Division of Biochemistry, Department of Chemistry, University of Pune, Pune 411007, India

a r t i c l e

i n f o

Article history: Received 15 July 2014 Received in revised form 18 October 2014 Accepted 23 October 2014 Available online 31 October 2014 Keywords: Iminosugars Lactams Halogen Conformations Inhibitors

a b s t r a c t A concise synthesis of four C-3 fluoro/chloro-D-xylono-d-lactams 3/4 has been reported. The methodology involves Corey–Link approach with suitably protected 3-oxo-D-gluco-furanose to introduce F/Cl as well as ester/amide functionalities at C-3 of glucose. In next steps, 5,6-O-isopropylidene group was converted to the 5-azido xylosugars that on opening of 1,2-acetonide group, and intramolecular Schmidt–Boyer reaction with TFA/H2O, in one pot, afforded lactams 3/4. Conformational aspect of d-lactams was studied by the 1H NMR spectroscopy. The halogenated d-lactams 3/4 showed no inhibition against different glycosidase enzymes. Ó 2014 Elsevier Ltd. All rights reserved.

1. Introduction Iminosugars are sugar mimics with the nitrogen atom instead of the oxygen atom in a ring. Analogues of iminosugars are potent therapeutics in the treatment of diabetes, obesity, Gaucher disease, and viral infection including AIDS due to their inhibition, and/or modulatory action toward a wide range of enzymes that act as carbohydrate recognizing proteins.1–5 Nojirimycin (NJ) 1a (Fig. 1) is the first molecule of iminosugar family that was found to be an inhibitor of several glycosidases. The presence of aminal moiety in 1a was found to be susceptible to enzyme hydrolysis, and therefore aminal moiety was reduced to give 1-deoxynojirimycin (DNJ) 1b which showed better glycosidase inhibitory activity than parent molecule.4–7 On the contrary, the microbial oxidation of aminal group in 1a led to the discovery of D-glucono-d-lactam 2 which, although nonbasic, was found to be a selective glycosidase inhibitor.8 This activity of 2 was attributed to the geometric resemblance with the flat ‘oxonium’ ion transition state of the glycosidase processes due to the involvement of sp2 hybridized carbonyl group, and the tautomeric form of amide which is able to act as both imine as well as 2-hydroxyl group suitable for the hydrogen bonding.9–11

⇑ Corresponding author.  

E-mail address: [email protected] (D.D. Dhavale). Both the authors contributed equally.

http://dx.doi.org/10.1016/j.carres.2014.10.023 0008-6215/Ó 2014 Elsevier Ltd. All rights reserved.

HO

H N

HO

HO R OH

H N

HO

OH

OH

OH

1a,1b

2

H N

O

NJ 1a; R = OH 2, Glucono -δ-lactam DNJ 1b; R = H

HO

H N

O OH

HO X HN

X AcO 3a,3b

AcO

3a; X=Cl 3b; X=F

O OH O

4a,4b

4a; X=Cl 4b; X=F

Figure 1. Iminosugars and glycono-d-lactams.

In view of this, a number of polyhydroxylated-c-and-d-lactams were synthesized. For example Lillelund et al. have reported the synthesis of D-gluco-/D-manno-/D-galacto-fagomine lactams, and showed the D-galacto-d-lactam to be more potent against b-galactosidase (Aspergillus oryzae).12 Wang et al. have reported the synthesis of N-substituted d- and e-hexanolactams which showed weak inhibition of wild type b-glucocerebrosidase however, were found to be highly potent pharmacological chaperones for treatment of N370S mutant Gaucher disease.10,13 Fleet et al. have synthesized L-fuconic-d-lactams which showed weak but specific a14 L-fucosidase inhibitory activity. Takeuchi and co-workers have synthesized eight stereoisomers of the D-glucono-d-lactams, studied their conformations by X-ray crystallography, and correlated with the glycosidase inhibitory activity.15 All these glycono-d-lactams were synthesized either from azido sugar lactones by internal

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azide reduction–cyclization or by one pot oxidation of sugar derived d-amino-alcohols/aldehydes.12–19 In addition, intramolecular Schmidt–Boyer reaction of d-azido aldehydes/ketones, under acidic conditions, also afforded corresponding glycono-d-lactams.20,21 Although a variety of sugar-d-lactams are known, the xylono-d-lactams with halogen (F/Cl) substitution, to the best of our knowledge, are not known. In medicinal chemistry, the introduction of lighter halogen groups such as fluorine or chlorine is known to enhance the potency of a molecule as a drug candidate due to the presence of strong CAF/CACl bond that increases the lipophilicity, and gives more resistance power to metabolic degradation.22,23 Iminosugars with Cl/F atom were investigated to get potent drug candidates.24–26 Inspired by this observation and as part of our continuous efforts in the area of iminosugars,27,28 we report here synthesis of D-xylono-d-lactams 3a/3b, and 4a/4b (Fig. 1) with highly functionalized C-3 quaternary center having Cl/F, and hydroxymethyl/amide functionalities, and study of their glycosidase inhibitory activity. An obvious way to introduce chlorine/fluorine atom in the iminosugar framework is by SNi/SN2 displacement of hydroxyl group (by converting into good leaving group) using Cl /F as nucleophiles with retention/inversion of configuration at different positions in the iminosugar.29,30 Other method involves chlorocyclization of sugar derived aminoalkenitols using Pd(II)/CuCl2.31 Alternatively, gem-difluorinated iminosugars have been synthesized by using Percy’s method via the [2,3] Wittig rearrangement of difluoroallylic alcohols.32,33 Our approach to the halogenatedxylono-d-lactams involves introduction of the halogen functionality by the modified Corey–Link34–36 reaction with C-3 trichlorocarbinol-D-glucofuranose while; the d-lactam skeleton was visualized by intramolecular Schmidt–Boyer37–39 reaction with subsequently obtained 5-azido-1,2-O-isopropylidene-a-D-xylofuranose. Our results in the successful application of the above methodology are described herein. 2. Results and discussion 2.1. Synthesis of d-lactams Recently, we have utilized the Corey–Link34–36 approach with suitably protected D-gluco, D-allo, and D-manno-5-oxo-furanoses for the synthesis of iminosugars,40 and D-gluco-3-oxofuranose for the synthesis of C-3 azido C3/C4 trans vicinal diacid which was found to be c-turn mimetic.41 Inspired with this observation, we applied this approach to get halo-substituted sugar framework. Thus, as shown in Scheme 1, the reaction of 1,2:5,6-di-O-isopropylidene-3-oxo-a-D-glucofuranose 5 with CHCl3 in the presence of LHMDS in THF at 78 °C afforded exclusive formation of 3(R)-tri-

O

O H

O

O

O O

O

H

O

LHMDS, CHCl3 -78 oC, 65%

O

6 CsF, DBU, t-BuOH, MeOH / amine

DBU, t-BuOH, MeOH / amine

O

H Cl O

O

O O O

R

O

HO

5

O

O

Cl3C

H

O F O

O

O O

R

Scheme 1. Synthesis of chloro/fluoro methyl ester/amides.

chloromethyl carbinol 6.42,43 The observed high stereoselectivity at C-3 is due to the presence of-a-oriented 1,2 acetonide group that hinders attack of nucleophile to the C-3 carbonyl group from the Re-face’.21,23 Treatment of 6 with DBU in methanol afforded 3(S)chloro methyl ester 7 in 85% yield.44 This Corey–Link reaction of 6 with DBU is known to proceed via in situ formation of a-oriented dichloroepoxide followed by nucleophilic attack of the chloride ion (as internal nucleophile) at C-3 from the opposite side of the dichloroepoxide to give 3b-chloro-3a-acid chloride that on methanolysis affords 7. At this stage, we thought of using fluoride ion as an external nucleophile in the Corey–Link reaction as reported for the synthesis of a-fluoro carboxylic acids.45 Thus, reaction of 6 with CsF (4 equiv) and DBU in methanol at 35 °C afforded a mixture of 3b-chloro/fluoro-3a-methylester in the 1:4 ratio. This could be due to the competitive pathways between the internal (Cl ) and external (F ) nucleophiles. To overcome this problem, we attempted the reaction by using 5, 7, and 10 equivalents of CsF, and the best result was obtained with CsF (10 equiv) that led to the exclusive formation of 3b-fluoro-3a-methylester 8 in 80% yield as the only isolable product. As this reaction involves in situ formation of acid chloride (on opening of dichloroepoxide), it occurred to our mind to trap the acid chloride with different nucleophilic amines in a synergetic way (weaker nucleophiles as compared to Cl/F) to get halogen substituted amide sugars. Robert Stick, and co-workers reported the reaction of 6 with DBU using benzylamine in DCM, and isolated 3b-chloro 3a-benzylamide in 37% yield. However, the reaction in the presence of external nucleophile like CsF, and benzylamine to get 3b-fluoro 3a-amide is not reported. At our hand, the reaction of 6 with DBU, and benzylamine in t-BuOH (instead of DCM) at room temperature gave 3b-chloro-3a-benzylamide 9a in 88% yield. The better yield obtained for 9a by changing solvent from DCM (37%) to t-BuOH (88%) is attributed to the high solvation ability of chloro benzylamide as a product in t-BuOH as compared to DCM that lowers the activation energy for its formation through solvation in t-BuOH. This fact is supported by using more polar protic solvent like dioxane/H2O (1:1.5) in the presence of NaOH (2 equiv) that afforded 9a in 76% yield (Table 1, entries 1 and 2). With this success, the above reaction was generalized by using a combination of either NaOH-dioxane/H2O or DBU-t-BuOH with different nucleophilic amines (3 equiv) like morpholine, propargylamine, 2-amino pyridine, and ethanolamine that afforded corresponding 3b-chloro-3a-amides (9b–9e) in high yield (Table 1, entries 3–10). The reaction of 2-amino pyridine in DBU/t-BuOH led to the formation of a complex mixture however, the same reaction in NaOH (2 equiv) in dioxane/H2O gave 9d in 71% yield (Table 1, entries 7 and 8). This observation could be attributed to the high solubility of 2-aminopyridine in dioxane/H2O as compared to tBuOH. Encouraged with this observation, we used CsF as an external nucleophile in the reaction. Thus, reaction of 6 with CsF (10 equiv) in benzylamine, morpholine, propargylamine, and ethanolamine (3 equiv) gave corresponding 3b-fluoro-3a-amides (10a– 10d) in good yields (Table 1, entries 11–14). The formation of fluoro amides (10a–10d) in high yields is striking as the nucleophilicity of fluoride ion in polar protic solvent is known to be low due to the tight solvation through intermolecular hydrogen bonding. However, our results are in accordance with the recent report of Kim et al.,46,47 who has given a mechanistic study on enhancement of nucleophilic fluorination of alkali metal fluorides in polar protic solvent like t-BuOH. According to this report, the CsF forms intermolecular H-bonding with the t-BuOH, which generate a solvated ‘flexible’ fluoride ion species by weakening ionic bonding of the alkali metal fluoride thus making CsF as a good nucleophile.48,49 In addition, more efficient solvation of product namely halogenated amide 9/10 is another favorable factor that facilitates reaction in polar protic solvent to give high yield.44

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The utility of halogenated sugars (7, 8, 9e, and 10d) was demonstrated by converting them into D-xylono-d-lactams (Schemes 2 and 3). For this purpose, we thought of reducing methyl ester group in 7 in to primary alcohol using LAH. Thus, reaction of chloro-methyl ester 7 with LAH in THF under variety of reaction conditions of solvent, and temperature led to the formation of complex mixture. However, the ester reduction was smoothly occurred with NaBH4 (10 equiv) in methanol at 0–25 °C to give chloro-hydroxymethyl compound that was directly subjected to acylation using pyridine in Ac2O to afford 3b-chloro-3a-acetoxymethyl 11a in 90% yield. Similarly, reaction of fluoro-methylester 8 with NaBH4 in methanol followed by acetylation gave 3b-fluoro-3a-acetoxymethyl 12a in 92% yield.50 In the subsequent step, the 5,6-acetonide functionality in 11a/12a was hydrolyzed individually using AcOH/H2O (65%) to give corresponding diol compound 11b/12b. Reaction of diol 11b/12b with sodium metaperiodate in THF/H2O followed by NaBH4 reduction afforded substituted-Dxylo-furanose 11c/12c. In the next step, the individual reaction of 11c/12c with Tf2O in pyridine at 10 °C followed by nucleophilic displacement with NaN3 in dry DMF afforded the corresponding 5 azido-D-xylo-furanose 11d/12d in good yields. In the next step, the 1,2 acetonide cleavage, and intramolecular Schmidt reaction was attempted in one pot. Thus individual reaction

Table 1 Reaction of 6 with halide and amine nucleophiles

b # * !

Entry

Nucleophile*

Amine nucleophile (3 equiv)

Reaction conditions# base!, solvent

Product, yield (%)b

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl CsF CsF CsF CsF

Benzylamine Benzylamine Morpholine Morpholine Propargyl amine Propargyl amine 2-Amino pyridine 2-Amino pyridine Ethanol amine Ethanol amine Benzylamine Morpholine Propargyl amine Ethanol amine

NaOH dioxane/H2O DBU t-BuOH NaOH dioxane/H2O DBU t-BuOH NaOH dioxane/H2O DBU, t-BuOH NaOH dioxane/H2O DBU, t-BuOH NaOH dioxane/H2O DBU t-BuOH DBU t-BuOH DBU t-BuOH DBU t-BuOH DBU t-BuOH

9a, 76 9a, 88 9b, 84 9b, 88, 9c, 62 9c, 78 9d, 71 — 9e, 76 9e, 88 10a, 81 10b, 84 10c, 65 10d, 90

Yields are after column purification. All reactions were performed at rt for 1.5–2 h. Cl acts as an internal nucleophile. NaOH (2 equiv) or DBU (4 equiv) was used in the reaction.

HO

O O

a)

7,8

H

O

O

X

b)

HO H

O

X

O

AcO

H

HO

O

H N 3a, 3b

O

AcO

11b, X=Cl, 88% 12b, X=F, 86%

N3 H e)

HO

11c, X=Cl, 90% 12c, X=F, 92%

d)

O

f)

O

X

O

AcO

11a, X=Cl, 90% 12a, X=F, 92%

O

c)

O

X

OH X AcO

O O

AcO

11e, X=Cl, 72% 12e, X=F, 70%

11d, X=Cl, 86% 12d, X=F, 90%

Scheme 2. Synthesis of d-lactams 3a and 3b. Reagents and conditions: (a) (i) NaBH4, MeOH, (ii) Ac2O, Pyridine, DCM; (b) 65% AcOH/H2O, 50 °C, 3.5 h; (c) (i) NaIO4, THF/H2O, (ii) NaBH4, MeOH; (d) (i) Tf2O, Pyridine, DCM, (ii) NaN3, DMF; (e) TFA/H2O (5:1) 10–12 h; (f) TFA, 10 h.

HO

O H

O

9e, 10d

O

O

a) X AcO

HN

b)

O

H O

c) X

O

HN

AcO

HO

O

X

O O

H

HO

O AcO

O

HN

O

13c, X=Cl, 86% 14c, X=F, 81%

13b, X=Cl, 88% 14b, X=F, 83%

13a, X=Cl, 92% 14a, X=F, 92%

O

d) H N

f) 4a/4b

HO X HN

O OH O

N3

e)

H

O

X AcO

HN

O O

O

AcO

13e, X=Cl, 70% 14e, X=F, 72%

13d, X=Cl, 90% 14d, X=F, 82%

Scheme 3. Synthesis of d-lactams 4a and 4b. Reagents and conditions: (a) Ac2O, Pyridine, DCM; (b) 65% AcOH/H2O, 50 °C, 3.5 h; (c) (i) NaIO4, THF/H2O, (ii) NaBH4, MeOH; (d) (i) Tf2O, Pyridine, DCM, (ii) NaN3, DMF; (e) TFA/H2O (5:1) 10–12 h, rt; (f) TFA, 10 h, rt.

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N3 O

11d14d

HO X

OH

X

O HO

R

OH

R

tive) is less favored due to the presence of electron withdrawing groups (hydroxyl, and halogen) which make the C1AC2 bond more electron deficient thus diminishing its migratory aptitude.51

N

N

N

2.3. Conformational study

H

A

N

It is known that the piperidine iminosugars exist in 4C1 or 1C4 conformation depending on the orientation of substituents in the ring that affects binding properties with glycosidases, and in turn inhibitory potential. However, the hydroxyl/alkyl substituted dlactams adopt half chair conformation.53 As the targeted D-xylono-d-lactams 3/4 have halogen and the CH2OH/amide substituents at the c-position to the ring nitrogen, we considered two half chair conformations A, and B, respectively (Fig. 3). For the determination of conformations of 3/4, the coupling constant value between the H5, and the H4 proton is decisive. The coupling constant values are listed in Tables 1 and 2 (SI). In case of the chloro/amide substituted d-lactams 4a, and its acetyl derivative 13e as well as for the fluoro-amide substituted d-lactams 4b, and 14e (acetyl derivative), the H5a appeared as a broad triplet with large coupling constants (J5a,5e  J5a,4a 11.0 Hz) that require the axial orientation of the H4. These spectral data suggest that these compounds exist in the preferred conformation A. An analogous observation was noticed for the fluoro, and CH2OH substituted d-lactam 3b, its acetate derivative 12e as well as chloro-CH2OAc 11e wherein; the H5a appeared as a doublet of doublet with large coupling constants (J5a,5e 12.0, and J5a,4a 8 Hz) suggesting the preferred half chair conformation A. However, in case of chloro-CH2OH d-lactam 3a the H5a appeared as only doublet with geminal coupling constant J5a,5e 11.5 Hz with no coupling with the H4. These data indicate that the 3a is either existing as a half chair conformation B or there is a little twist in a half chair conformation A, due to the intramolecular hydrogen bonding between CH2OH, and large size chlorine atom that makes the dihedral angle between the H5, and the H4 close to 90 ° making negligible coupling constant between the H5, and H4.

N N N N

HO X

O

HO R

H

N

HO X

H

O R

H

HO B

C

H

O N HO

H

NH

HO X

OH R

R

HO

O

X

X = F/Cl, R = CH2OAc/CONH(CH2)2OAc Figure 2. Mechanism of Intramolecular Schmidt Boyer reaction.

of 11d/12d with TFA/H2O (5:1) at 0 °C for 30 min, and at 25 °C for 2 h, afforded the d-azido hemiacetal. To this mixture, at 25 °C, an additional amount of TFA was added, and the reaction mixture was stirred for 10 h to get the 3-chloro/fluoro acetoxymethyl-D-xylono-dlactams 11e/12e. In the final step, deprotection of acetate group by using TFA afforded the 3-chloro/fluoro hydroxymethyl-D-xylonod-lactam 3a/3b.51 Having success in this protocol, the above reaction sequence was employed with 3-Cl/F-hydroxyethylamides 9e/10d. Thus, as shown in Scheme 3, acetylation of 9e/10d and conversion of 5,6-acetonide group to C-5 azido group afforded 13d/14d. The intramolecular Schmidt reaction of 13d/14d using TFA/H2O followed by deprotection of aceotoxy group using TFA gave 3-chloro/ fluoro hydroxyethyl-D-xylono-d-lactam 4a/4b.51

2.4. Enzyme inhibition study The glycosidase inhibitory activities of compounds 3a, 3b, 4a, 4b were studied against following enzymes: b-galactosidase (bovine liver), b-galactosidase (almond), a-mannosidase (almond), a-mannosidase (jack bean), a-galactosidase (almond), N-acetyl-bD-glucosaminidase (bovine kidney), N-acetyl-b-D-glucosaminidase (jack bean), a-glucosidase (baker’s yeast), a-glucosidase (rice), and a-fucosidase (bovine kidney). However, none of the xylonod-lactams were found to be potent inhibitors of any glycosidases at 10 mM concentration.

2.2. Plausible mechanism The plausible mechanism for the formation of d-lactam could be explained as follows. We believe that, opening of 1,2-acetonide group in 11d–14d led to hemiacetal that attains open chain structure A of sugar-d-azido aldehyde in which CO group is parallel with the azido group so as to accommodate maximum orbital overlap (Fig. 2). Formation of a new CAN bond gives azidohydrin B (which is an anomeric mixture), wherein; the leaving nitrogen group is in axial position. As the reaction proceeds, formation of the CO-group with concomitant antiperiplanar 1,2 hydride shift, and elimination of the nitrogen atom led to the d-lactam. Although, one assumes nitrogen inversion52 leading to the equatorial orientation of nitrogen atom as a leaving group (azidohydrin C), the migration of the antiperiplanar CAC bond (leading to the N-formyl pyrrole deriva-

H H X R

In summary, the Corey–Link approach was successfully exploited in a multi component fashion to get C-3 halo, and C-3 alcohol/amide substituted D-gluco configured synthons, which were converted to the 5-azido-xylose derivative. Hydrolysis of 1,2 acetonide

H

H HO

3. Conclusions

H

H N

H O

OH

A

X H H N

O

H R OH

OH

B

Figure 3. Conformations of-D-xylono-d-lactams.

X = F, Cl; R= alcohol/amide

N. Bhuma et al. / Carbohydrate Research 402 (2015) 215–224

functionality, and intramolecular Schmidt reaction were performed as the two step one pot cascade reaction to get xylono-d-lactams in good yield. The newly synthesized-d-lactams showed no inhibition activity against variety of glycosidase enzymes. 4. Experimental 4.1. General All reactions were carried out with distilled and dried solvents using oven-dried glassware. 1H NMR (300/400/500 MHz) and 13C NMR (75/100 MHz) were recorded in CDCl3/CD3OD/D2O depending on the solubility of compound. Chemical shifts are reported in d unit with reference to TMS as an internal standard and coupling constant (J) values are given in Hertz. Melting points are uncorrected. IR spectra were recorded with a FTIR as a thin film or using KBr pellets and are expressed in cm 1. Optical rotations were measured using Polarimeter. Mass samples were analyzed by High-resolution mass spectrometry using positive ion ESI-TOF and MALDITOF/TOF. Thin-layer chromatography was performed on silica gel precoated plates (0.25 mm, 60 F254). Column chromatography was carried out using silica gel (100–200 mesh). Methanol, DCM and THF were purified and dried by standard procedure. 4.2. 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-3-Cmethoxycarbonyl-a-D-glucofuranoside (7) To a trichloro carbinol compound 6 (2.0 g, 5.48 mmol) in methanol (10 mL) at rt was added DBU (3.3 mL, 21.94 mmol) and reaction mixture was stirred for 1.5–2 h. After neutralization with NH4Cl, methanol was removed under reduced pressure, and compound was extracted with EtOAc (3  15 mL). The combined organic layer was washed with brine, dried over Na2SO4, concentrated in vacuum, and purified by column chromatography by using EtOAc/hexane (9:1) as an eluent to afford 7 as a thick liquid (1.56 g, 85% yield). [a]24 D +102.62 (c 0.43, CHCl3). IR (neat): mmax 1749, 847, 787 cm 1. 1H NMR (300 MHz, CDCl3): d 5.96 (d, J = 3.5 Hz, 1H), 4.80 (d, J = 7.0 Hz, 1H), 4.78 (d, J = 3.5 Hz, 2H), 4.42–4.31 (m, 1H), 4.11 (d, J = 7.0 Hz, 2H), 3.84 (s, 3H), 1.53 (s, 3H), 1.43 (s, 3H), 1.34 (s, 3H), 1.32 (s, 3H) ppm. 13C NMR (75 MHz, CDCl3): d 165.6, 113.7, 109.4, 104.6, 88.3, 81.4, 74.4, 73.8, 66.3, 52.7, 26.8, 26.6, 26.1, 24.9 ppm. HRMS: m/z calcd for C14H21ClO7Na [M+Na]+ 359.0873; found 359.0873. 4.3. 3-Deoxy-3-fluoro-1,2;5,6-di-O-isopropylidene-3-Cmethoxycarbonyl-a-D-glucofuranoside (8) To trichloro carbinol compound 6 (2.0 g, 5.48 mmol) in t-BuOH (10 mL), methanol (10 mL) at rt was added cesium fluoride (8.05 g, 54.8 mmol). To this reaction mixture DBU (3.3 mL, 21.94 mmol) was added and stirred for 1.5–2 h. The reaction mixture was neutralized with NH4Cl, t-BuOH, MeOH was removed under reduced pressure, and compound was extracted with EtOAc (3  20 mL). The combined organic layers were washed with brine, dried over Na2SO4, concentrated in vacuum, and compound purified by column chromatography by using EtOAc/hexane (9:1). 1.35 g, 80% yield. white solid: mp 81–84 °C. [a]25 D +75.32 (c 1.03, CHCl3). IR (neat): mmax 1755, 748 cm 1. 1H NMR (CDCl3, 300 MHz): d 6.01 (d, J = 3.8 Hz, 1H), 4.70 (dd, J = 14.3, 3.8 Hz, 1H), 4.65 (dd, J = 26.2, 8.1 Hz, 1H), 4.22–4.30 (m, 1H), 4.02–4.17 (m, 2H), 3.85 (s, 3H), 1.56 (s, 3H), 1.40 (s, 3H), 1.33 (s, 3H), 1.31 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 165.3 (d, J = 24.2 Hz), 113.6, 109.7, 105.3, 98.8 (d, J = 195.7 Hz), 84.7 (d, J = 36.8 Hz), 81.7 (d, J = 20.7 Hz), 72.0 (d, J = 5.7 Hz), 66.7, 52.6, 26.7, 26.4, 26.1, 24.8 ppm. HRMS: m/z calcd for C14H21FO7Na [M+Na]+ 343.1168; found 343.1173.

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4.4. Method A: general procedure for the synthesis of compounds (9a–9e) using DBU/t-BuOH To trichloro carbinol compound 6 (1 mmol) in t-BuOH (2 mL) at rt was added the DBU (4 mmol), followed by immediate addition of amine (3 mmol) and stirred for 1.5–2 h. The reaction mixture was neutralized with NH4Cl, t-BuOH was removed under reduced pressure and compound was extracted with EtOAc (3  20 mL). The combined organic layers were washed with brine, dried over Na2SO4, concentrated in vacuum, and purified by column chromatography using EtOAc/hexane. For 9a, 9c, (10–15% EtoAc/hexane), for 9b (30–40% EtOAc/hexane), for 9d, 9e (60% EtOAc/hexane). 4.5. Method B: general procedure for the synthesis of compounds (9a–9e) using NaOH/dioxane/H2O To trichloro carbinol compound 6 (1 mmol) in dioxane (1 mL) at 10 °C NaOH (2 mmol) dissolved in 1.5 mL of water was added, followed by immediate addition of amine (2 mmol) and stirred for 1.5–2 h. The reaction mixture was neutralized with NH4Cl, Dioxane was removed under reduced pressure and compound was extracted with EtOAc. Workup and purification is as mentioned as above. 4.5.1. 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-3-C(benzylamino)carbonyl-a-D-glucofuranoside (9a) 0.25 g, 88%, thick liquid. [a]31 D +11.46 (c 0.72, CHCl3). IR (neat): mmax 3440–3330 (br), 1681, 1377, 1068, 844, 756 cm 1. 1H NMR (300 MHz, CDCl3): d 7.93 (s, 1H, ex with D2O), 7.40–7.20 (m, 5H), 5.85 (d, J = 3.0 Hz, 1H), 4.98 (d, J = 3.0 Hz, 1H), 4.52–4.35 (m, 4H), 4.18 (dd, J = 9.0, 6.2 Hz, 1H), 4.03 (dd, J = 9.0, 5.2 Hz, 1H), 1.56 (s, 3H), 1.37 (s, 3H), 1.22 (s, 3H), 1.06 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 164.3, 137.2, 128.6, 128.0, 127.6, 113.8, 110.6, 103.3, 88.3, 80.2, 76.0, 73.3, 67.8, 44.1, 27.0, 26.7, 25.6, 25.0 ppm. HRMS: m/z calcd for C20H26ClNO6Na [M+Na]+ 434.1346; found 434.1354. 4.5.2. 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-3-C-(Nmorpholino)carbonyl-a-D-glucofuranoside (9b) 0.24 g, 88%, white solid: mp 187–188 °C. [a]29 75.38 (c 0.53, D CHCl3). IR (neat): mmax 1636, 1024, 757, 676 cm 1. 1H NMR (300 MHz, CDCl3): d 6.04 (d, J = 4.0 Hz, 1H), 5.14 (d, J = 1.4 Hz, 1H), 4.73 (d, J = 4.0 Hz, 1H), 4.56 (ddd, J = 7.1, 6.2, 1.4 Hz, 1H), 4.18 (dd, J = 8.6, 6.2 Hz, 1H), 4.03 (dd, J = 8.6, 7.1 Hz, 1H), 3.82– 3.58 (br m, 8H), 1.50 (s, 3H), 1.47 (s, 3H), 1.36 (s, 3H), 1.32 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 163.6, 113.0, 108.2, 104.5, 86.8, 82.8, 75.4, 72.3, 66.4, 64.6, 32.7, 26.8, 26.3, 26.1, 25.0 ppm. HRMS: m/z calcd for C17H27ClNO7 [M+H]+ 392.1476; found 392.1479. 4.5.3. 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-3-C(propargylamino)carbonyl-a-D-glucofuranoside (9c) 0.26 g, 78%, white solid: mp 107–108 °C. [a]30 D +19.43 (c 0.33, CHCl3). IR (neat): mmax 3288, 1685, 1390, 1070, 842, 758 cm 1. 1H NMR (300 MHz, CDCl3): d 8.04 (br s, 1H, ex with D2O), 5.84 (d, J = 3.0 Hz, 1H), 4.94 (d, J = 3.0 Hz, 1H), 4.48–4.36 (m, 2H), 4.28– 4.20 (m, 1H), 4.14–4.04 (m, 3H), 2.27 (t, J = 2.6 Hz, 1H), 1.55 (s, 3H), 1.53 (s, 3H), 1.41 (s, 3H), 1.36 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 164.1, 114.0, 110.8, 103.3, 88.1, 80.2, 78.5, 75.4, 73.3, 72.3, 68.0, 30.0, 27.0, 26.6, 26.2, 25.1 ppm. HRMS: m/z calcd for C16H22ClNO6Na [M+Na]+ 382.1033; found 382.1037. 4.5.4. 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-3-C-(2aminopyridyl)carbonyl-a-D-glucofuranoside (9d) 0.24 g, 71%, white solid: mp 110–111 °C. [a]29 D +27.9 (c 1.05, CHCl3). IR (neat): mmax (br), 1697, 1435, 1070, 840, 779 cm 1. 1H NMR (300 MHz, CDCl3): d 10.15 (br s, 1H, ex with D2O),

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8.40–8.20 (m, 2H), (td, J = 7.8, 1.4 Hz, 1H), 7.07 (dd, J = 7.2, 5.3 Hz, 1H), 5.92 (d, J = 2.8 Hz, 1H), 5.0 (d, J = 2.8 Hz, 1H), 4.63 (d, J = 8.1 Hz, 1H), 4.55–4.44 (m, 1H), 4.27 (dd, J = 9.0, 6.7 Hz, 1H, H6a), 4.14 (dd, J = 9.0, 5.2 Hz, 1H), 1.60 (s, 3H), 1.57 (s, 3H), 1.45 (s, 3H), 1.38 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 162.6, 151.2, 148.0, 138.1, 120.2, 114.4, 114.1, 111.1, 103.6, 88.2, 80.3, 76.6, 73.5, 67.8, 27.0, 26.7, 26.0, 25.2 ppm. HRMS: m/z calcd for C18H24ClN2O6 [M+H]+ 399.1323; found 399.1325. 4.5.5. 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-3-C(hydroxyethylamino)carbonyl-a-D-glucofuranoside (9e) 2.75 g, 88% yield, thick liquid. [a]26 D +34.01 (c 1.27, CHCl3). IR (neat): mmax 3421–3317 (br), 1674, 1379, 1070, 842 cm 1. 1H NMR (300 MHz, CDCl3): d 7.82 (br s, 1H, ex with D2O), 5.88 (d, J = 3.2 Hz, 1H), 4.92 (d, J = 3.2 Hz, 1H), 4.55 (d, J = 8.2 Hz, 1H), 4.41 (ddd, J = 8.2, 6.5, 5.0 Hz, 1H), 4.22 (dd, J = 9.1, 6.5 Hz, 1H), 4.11 (dd, J = 9.1, 5.0 Hz, 1H), 3.82–3.70 (m, 2H), 3.60–3.41 (m, 2H), 2.2 (br s, 1H, ex with D2O), 1.48 (s, 3H), 1.38 (s, 3H), 1.35 (s, 3H), 1.24 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 165.1, 113.9, 110.6, 103.7, 88.3, 80.6, 76.1, 73.6, 67.6, 61.4, 42.7, 26.8, 26.7, 26.0, 25.0 ppm. HRMS: m/z calcd for C15H24ClNO7Na [M+Na]+ 388.1138; found 388.1143. 4.6. General procedure for the synthesis of compounds (10a– 10d) To trichloro carbinol 6 (1 mmol) in t-BuOH (2 mL) at rt was added CsF (10 mmol). To this reaction mixture DBU (4 mmol) was added followed by immediate addition of amine (3 mmol) and stirred for 1.5–2 h. Workup and purification is as mentioned above. Compounds were purified by column chromatography using EtOAc/hexane. For 10a, 10c, (10–15% EtoAc/hexane), 10b (30–40% EtOAc/hexane), 10d (60% EtOAc/hexane). 4.6.1. 3-Deoxy-3-fluoro-1,2;5,6-di-O-isopropylidene-3-C(benzylamino)carbonyl-a-D-glucofuranoside (10a) 0.16 g, 81% yield, white solid: mp 98–99 °C. [a]28 D +100.38 (c 0.36, CHCl3). IR (neat): mmax 3416 (br), 1685, 1531, 1377, 1080 cm 1. 1H NMR (300 MHz, CDCl3): d 7.34–7.24 (m, 5H), 6.77 (br s, 1H, ex with D2O), 5.98 (d, J = 4.0 Hz, 1H), 4.82–4.60 (m, 3H), 4.32 (dd, J = 15.0, 4.0 Hz, 1H), 4.28–4.18 (m, 1H), 4.17–4.10 (m, 2H), 1.62 (s, 3H), 1.35 (s, 3H), 1.30 (s, 3H), 1.29 (s, 3H) ppm. 13 C NMR (CDCl3, 75 MHz): d 163.9 (d, J = 20.7 Hz), 137.6, 128.5, 127.5, 127.4, 114.0, 110.0, 105.3, 100.6 (d, J = 195.8 Hz), 85.2 (d, J = 38.0 Hz), 81.7 (d, J = 19.6 Hz), 72.1 (d, J = 6.9 Hz), 67.0, 43.1, 27.0, 26.6, 26.2, 25.2 ppm. HRMS: m/z calcd for C20H26FNO6Na [M+Na]+ 418.1641; found 418.1630. 4.6.2. 3-Deoxy-3-fluoro-1,2;5,6-di-O-isopropylidene-3-C-(Nmorpholino)carbonyl-a-D-glucofuranoside (10b) 0.22 g, 84% yield, white solid: mp 154–155 °C. [a]29 D +75.45 (c 0.37, CHCl3). IR (neat): mmax 34437 (br), 1643, 1257 1112 cm 1. 1 H NMR (300 MHz, CDCl3): d 6.04 (d, J = 4.0, 1H), 5.21 (dd, J = 30, 4.3 Hz, 1H), 4.68 (dd, J = 13.8, 4.0 Hz, 1H), 4.40–4.27 (m, 1H), 4.10–3.95 (m, 2H), 3.80–3.50 (br m, 8H), 1.50 (s, 3H), 1.43 (s, 3H), 1.34 (s, 3H), 1.32 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 162.7 (d, J = 19.6 Hz), 113.3, 109.0, 105.0, 102.3 (d, J = 199.2 Hz), 84.3 (d, J = 32.2 Hz), 81.7 (d, J = 20.7 Hz), 73.0 (d, J = 4.6 Hz), 66.6, 65.5, 65.4, 46.3, 43.5, 27.0, 26.4, 26.0, 25.3 ppm. HRMS: m/z calcd for C17H26FNO7Na [M+Na]+ 398.1590; found 398.1590. 4.6.3. 3-Deoxy-3-fluoro-1,2;5,6-di-O-isopropylidene-3-C(propargylamino)carbonyl-a-D-glucofuranoside (10c) 0.17 g, 65% yield, thick liquid. [a]28 D +48.97 (c 0.98, CHCl3). IR (neat): mmax 3367–3288 (br), 1687, 1379, 871, 786 cm 1. 1H NMR (300 MHz, CDCl3): d 6.68 (br s, 1H, ex with D2O), 5.99 (d,

J = 3.8 Hz, 1H), 4.76–4.56 (m, 2H, H4), 4.28–3.92 (m, 5H, H5), 2.27 (t, J = 2.8 Hz, 1H), 1.61 (s, 3H), 1.40 (s, 3H), 1.34 (s, 3H), 1.31 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 163.8 (d, J = 21.6 Hz), 114.1, 110.0, 105.3, 100.4 (d, J = 196.3 Hz), 85.0 (d, J = 32.2 Hz), 82.0 (d, J = 19.9 Hz), 78.7, 72.2 (d, J = 6.1 Hz), 72.0, 67.0, 29.1, 26.9, 26.6, 26.2, 25.1 ppm. HRMS: m/z calcd for C16H22FNO6Na [M+Na]+ 366.1328; found 366.1327. 4.6.4. 3-Deoxy-3-fluoro-1,2;5,6-di-O-isopropylidene-3-C(hydroxyethylamino)carbonyl-a-D-glucofuranoside (10d) 1.6 g, 90% yield, thick liquid. [a]29 D +33.4 (c 0.4, CHCl3). IR (neat): mmax 3389 (br), 1681 cm 1. 1H NMR (300 MHz, CDCl3): d 6.91 (br s, 1H, ex with D2O), 5.98 (d, J = 3.8 Hz, 1H), 4.67 (dd, J = 8.3, 27.6 Hz, 1H), 4.65 (dd, J = 3.8, 14.8 Hz, 1H), 4.28–4.19 (m, 1H), 4.16–4.04 (m, 2H), 3.82–3.57 (m, 3H), 3.40–3.26 (m, 1H), 3.05–2.95 (br s, 1H, ex with D2O), 1.61 (s, 3H), 1.41 (s, 3H), 1.34 (s, 3H), 1.32 (s, 3H) ppm. 13 C NMR (CDCl3, 75 MHz): d 164.8 (d, J = 20.4), 110.2, 114.1, 105.3, 100.0 (d, J = 198 Hz), 84.9 (d, J = 38.7 Hz), 81.8 (d, J = 19.9 Hz), 72.0 (d, J = 6.6 Hz), 66.9, 60.7, 42.1, 26.9, 26.5, 26.1, 25.1 ppm. HRMS: m/ z calcd for C15H24FNO7Na [M+Na]+ 350.1615; found 350.1685. 4.7. General procedure for the preparation of compounds 11a, 12a, 13a, 14a To ester compound (7, 8) (1 mmol) in methanol at 0 °C, sodium borohydride (10 mmol) was added in three portions during 20 min. After 15 min, reaction mixture was allowed to attain to rt and stirred for 4 h. (Rf = 0.3, hexane/ethylacetate 8:2). Reaction mixture was neutralized by sat NH4Cl, MeOH was removed under reduced pressure, and compound was extracted with EtOAc (3  20 mL). Combined organic layers were dried over Na2SO4 and concentrated in vacuum. To the crude alcohol compound of 7, 8, 10d, 9e (pure compound 10d, 9e) (1 mmol) dissolved in DCM 5 mL, dry pyridine (2.5 mmol) was added at room temperature. Ac2O (2 mmol) was added and stirred for 4 h. (Rf 0.75, hexane/ ethyl acetate 8:2). The mixture was quenched with dilute CuSO4 (dissolved in H2O) solution. Compound was extracted with DCM (3  30 mL), combined organic layer was washed with water (2  20 mL), dried over Na2SO4, and purified by column chromatography using EtOAc/hexane. 4.7.1. 3-C-(Acetyloxy)methyl-3-Chloro-3-deoxy-1,2;5,6-di-Oisopropylidine-D-glucofuranoside (11a) 1.40 g, 90%, thick liquid. [a]28 D +40.76 (c 0.42, CHCl3). IR (neat): mmax 1747, 1063, 847, 776 cm 1. 1H NMR (300 MHz, CDCl3): d 5.82 (d, J = 3.3 Hz, 1H), 4.65 (dd, J = 6.2, 3.3 Hz, 2H), 4.28 (m, 1H), 4.06 (t, J = 8.6 Hz, 1H), 3.95 (dd, J = 8.6, 4.3 Hz, 1H), 3.86 (dd, J = 8.6 Hz, 1H), 2.07 (s, 3H), 1.46 (s, 3H), 1.36 (s, 3H), 1.27 (s, 6H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.1, 113.3, 109.7, 104.4, 86.4, 80.8, 77.0, 73.7, 67.4, 64.1, 26.8, 26.7, 26.5, 25.0, 20.7 ppm. HRMS: m/z calcd for C15H23ClO7Na [M+Na]+ 373.1029; found 373.1032. 4.7.2. 3-C-(Acetyloxy)methyl-3-deoxy-3-fluoro-1,2;5,6-di-Oisopropylidine-D-glucofuranoside (12a) 4.7 g, 92% yield, thick liquid. [a]23 D +53.34 (c 0.42, CHCl3). IR (neat): mmax 1745, 844, 751 cm 1. 1H NMR (300 MHz, CDCl3): d 5.91 (d, J = 3.8 Hz, 1H), 4.70 (dd, J = 23.4, 12.9 Hz, 1H), 4.66 (dd, J = 11.0, 3.8 Hz, 1H), 4.27 (dd, J = 34.8, 12.9 Hz, 1H), 4.32–4.24 (m, 1H), 4.12 (dd, J = 8.6, 6.9 Hz, 1H), 4.03 (dd, J = 8.6, 4.8 Hz, 1H), 3.90 (dd, J = 24.3, 8.6 Hz, 1H), 2.13 (s, 3H), 1.52 (s, 3H), 1.43 (s, 3H), 1.34 (s, 6H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.3, 113.2, 109.7, 104.6, 101.4 (d, J = 186.5 Hz), 82.7 (d, J = 38.1 Hz), 80.2 (d, J = 18.4 Hz), 71.6 (d, J = 6.9 Hz), 67.3, 62.0 (d, J = 20.7 Hz), 26.9, 26.8, 26.4, 25.1, 20.7 ppm. HRMS: m/z calcd for C15H23FO7Na [M+Na]+ 357.1325; found 357.1331.

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4.7.3. 3-C-(Acetyloxyethylamino)carbonyl-3-chloro-3-deoxy1,2;5,6-di-O-isopropylidene-a-D-glucofuranoside (13a) 3.20 g, 92% yield, thick liquid. [a]30 D +17.61 (c 0.52, CHCl3). IR (neat): mmax 3313, 1735, 1687, 1228, 1070, 759 cm 1. 1H NMR (300 MHz, CDCl3): d 7.72 (br s, 1H, ex with D2O), 5.85 (d, J = 3.3 Hz, 1H), 4.88 (d, J = 3.3 Hz, 1H), 4.50 (d, J = 8.2 Hz, 1H), 4.42–4.32 (m, 1H), 4.24–4.14 (m, 3H), 4.10 (dd, J = 8.8, 4.7 Hz, 1H), 3.66–3.46 (m, 2H), 2.06 (s, 3H), 1.54 (s, 3H), 1.47 (s, 3H), 1.37 (s, 3H), 1.34 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 172.0, 168.8, 114.0, 110.2, 103.7, 88.2, 80.8, 76.0, 73.8, 67.7, 63.0, 39.0, 27.1, 27.0, 26.2, 25.1, 21.0 ppm. HRMS: m/z calcd for C17H26ClNO8Na [M+Na]+ 430.1244; found 430.1212. 4.7.4. 3-C-(Acetyloxyethylamino)carbonyl-3-deoxy-3-fluoro1,2;5,6-di-O-isopropylidene-a-D-glucofuranoside (14a) 2.88 g, 92% yield, thick liquid. [a]29 D +49.54 (c 0.4, CHCl3). IR (neat): mmax 3383, 1739, 1691 1232, 1078, 1055, 751 cm 1. 1H NMR (300 MHz, CDCl3): d 6.79 (br s, 1H, ex with D2O), 5.99 (d, J = 3.8 Hz, 1H), 4.60 (dd, J = 27.6, 8.3 Hz, 1H), 4.55 (dd, J = 15.0, 3.8 Hz, 1H), 4.27–4.0 (m, 5H), 3.40–2.95 (m, 2H), 2.08 (s, 3H), 1.60 (s, 3H), 1.38 (s, 3H), 1.34 (s, 3H), 1.30 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.8, 164.2 (d, J = 21.0 Hz), 113.8, 109.7, 105.2, 100.3 (d, J = 195.7 Hz,), 85.0 (d, J = 38.7 Hz), 81.6 (d, J = 19.9 Hz), 72.0 (d, J = 6.6 Hz), 66.7, 62.7, 38.3, 26.8, 26.5, 26.0, 25.0, 20.6 ppm. HRMS: m/z calcd for C17H27FNO8 [M+H]+ 392.1721; found 392.1776. 4.8. General procedure for the synthesis of compounds 11b, 12b, 13b, 14b Compounds 11a, 12a, 13a, 14a were dissolved in acetic acid/ water (65%, mL) and stirred at 55 °C for 3 h. (Rf = 0.2, hexane/ethyl acetate 1:1). Reaction mixture was neutralized with sat. NaHCO3 solution and the compound was extracted with ethyl acetate (3  25 mL). Combined Organic layer was dried over Na2SO4, concentrated in vacuum, and purified by column chromatography using EtOAc/hexane. 4.8.1. 3-C-(Acetyloxy)methyl-3-chloro-3-deoxy-1,2-Oisopropylidine-a-D-glucofuranoside (11b) 1.55 g, 88% yield, yellow color solid: mp 91–95 °C. [a]23 D +43.123 (c 0.35, CHCl3). IR (neat): mmax 3409 (br), 1736, 753 cm 1. 1H NMR (300 MHz, CDCl3): d 5.89 (d, J = 3.5 Hz, 1H), 4.84 (d, J = 12.3 Hz, 1H), 4.72 (d, J = 3.5 Hz, 1H), 4.38 (d, J = 12.3 Hz, 1H), 4.10–3.95 (m, 2H, H5,), 3.85 (br d, J = 11.2 Hz, 1H), 3.72 (br d, J = 11.2 Hz, 1H), 3.34 (br s, 1H, ex with D2O), 2.87 (br s, 1H, ex with D2O), 2.14 (s, 3H), 1.52 (s, 3H), 1.34 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.6, 113.3, 104.2, 86.3, 79.6, 77.7, 70.2, 64.5, 64.1, 26.8, 26.7, 20.8 ppm. HRMS: m/z calcd for C12H19ClO7Na [M+Na]+ 333.0716; found 333.0718. 4.8.2. 3-C-(Acetyloxy)methyl-3-deoxy-3-fluoro-1,2-Oisopropylidene-a-D-glucofuranoside (12b) 2.27 g, 86% yield, white solid, mp 118–122 °C. [a]26 D +48.84 (c 1.0, CHCl3). IR (neat): mmax 3414 (br), 1738, 756 cm 1. 1H NMR (CDCl3, 400 MHz): d 5.91 (d, J = 3.8 Hz, 1H), 4.84 (t, J = 13.1 Hz, 1H), 4.66 (dd, J = 10.5, 3.8 Hz, 1H), 4.30 (dd, J = 33.9, 13.1 Hz, 1H), 4.10–3.80 (m, 2H, H4), 3.85 (dd, J = 11.2, 2.0 Hz, 1H), 3.72 (dd, J = 11.2, 4.3 Hz, 1H), 2.80 (br s, 1H, ex with D2O), 2.14 (s, 3H), 1.70 (br s, 1H, ex with D2O), 1.52 (s, 3H), 1.35 (s, 3H) ppm. 13C NMR (CDCl3, 100 MHz): d 170.7, 113.2, 104.4, 101.7 (d, J = 186.3 Hz), 82.6 (d, J = 37.7 Hz), 79.4 (d, J = 20.4 Hz), 67.9 (d, J = 6.6 Hz), 64.1, 62.2 (d, J = 20.4 Hz), 26.8, 26.4, 20.8 ppm. HRMS: m/z calcd for C12H19FO7Na [M+Na]+ 317.1012; found 317.1023.

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4.8.3. 3-C-(Acetyloxyethylamino)carbonyl-3-chloro-3-deoxy1,2-di-O-isopropylidene-a-D-glucofuranoside (13b) 1.75 g, 88% yield, thick liquid. [a]29 D +43.41 (c 0.73, CHCl3). IR (neat): mmax 3471–3385 (br), 1720, 1649, 1259, 1082 cm 1; 1H NMR (300 MHz, CDCl3): d 7.58 (br s, 1H, ex with D2O), 5.91 (d, J = 3.3 Hz, 1H), 4.84 (d, J = 3.3 Hz, 1H), 4.57 (d, J = 8.6 Hz, 1H), 4.41 (br, 1H, ex with D2O), 4.22 (t, J = 5.7 Hz, 2H), 4.0 (ddd, J = 8.6, 4.7, 2.8 Hz, 1H), 3.87 (dd, J = 11.4, 2.8 Hz, 1H), 3.75 (dd, J = 11.4, 4.7 Hz, 1H), 3.64–3.53 (m, 2H), 2.68 (br, ex with D2O), 2.08 (s, 3H), 1.54 (s, 3H), 1.36 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 171.3, 166.4, 114.0, 103.7, 87.5, 79.2, 76.4, 70.3, 64.0, 62.4, 39.3, 26.7, 20.8 ppm. HRMS: m/z calcd for C14H22ClNO8Na [M+Na]+ 390.0931; found 390.0926. 4.8.4. 3-C-(Acetyloxyethylamino)carbonyl-3-deoxy-3-fluoro1,2-di-O-isopropylidene-a-D-glucofuranoside (14b) 2.04 g, 83%, thick liquid. [a]29 D +53.0 (c 0.85, CHCl3). IR (neat): mmax 3433, 3387 (br), 1730, 1676, 1051, 875 cm 1. 1H NMR (300 MHz, CDCl3): d 7.20 (br s, 1H, ex with D2O), 5.98 (d, J = 3.6 Hz, 1H), 4.61 (dd, J = 27.6, 11.0 Hz, 1H), 4.57 (dd, J = 14.2, 3.6 Hz, 1H), 4.30–4.05 (m, 2H), 3.90–3.50 (m, 5H, H5), 3.20 (br s, 1H, ex with D2O), 2.08 (s, 3H), 1.58 (s, 3H), 1.33 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 171.3, 165.5 (d, J = 21.6 Hz), 113.8, 105.0, 100.2 (d, J = 195.7 Hz), 84.3 (d, J = 38.7 Hz), 80.3 (d, J = 19.9 Hz), 68.5 (d, J = 5.5 Hz), 63.6, 62.6, 38.4, 26.7, 26.4, 20.7 ppm. HRMS: m/z calcd for C14H22FNO8Na [M+Na]+ 374.1226; found 374.1233. 4.9. General procedure for synthesis of compounds 11c, 12c, 13c, 14c To a stirred solution of diol 11b, 12b, 13b, 14b (1 mmol) in THF/ water (6:1) 8 mL, sodium metaperiodate (1.5 mmol) was added at 0 °C. After 30 min the reaction mixture was allowed to attain rt and stirred for 2 h. (Rf = 0.8, hexane/ethyl acetate 6:4) The reaction mixture was filtered through the celite bed. Compound was extracted with ethylacetate (3  20 mL), dried over Na2SO4, and concentrated in vacuum. The crude compound was subjected to the next reaction as it is. To a stirred solution of crude aldehyde (1 mmol) in methanol, sodium borohydride (1 mmol) was added at 0 °C and stirred for 20 min at the same temperature (Rf = 0.7, hexane/ethyl acetate 7:3). The reaction mixture was neutralized by sat. NH4Cl and solvent was removed under reduced pressure. Residue was extracted with ethyl acetate (3  20 mL), combined organic layer was dried over Na2SO4, and concentrated. The crude compound was purified by column chromatography on silica gel using EtOAc/hexane. 4.9.1. 3-C-(Acetyloxy)methyl-3-chloro-3-deoxy-1,2-Oisopropylidene-a-D-xylofuranoside (11c) 0.72 g, 90% yield, thick liquid. [a]28 D +32.91 (c 1.96, CHCl3). IR (neat): mmax 3473 (br), 1745, 871 cm 1; 1H NMR (300 MHz, CDCl3): d 5.96 (d, J = 3.4 Hz, 1H), 4.70 (d, J = 3.4 Hz, 1H), 4.58 (d, J = 12.2 Hz, 1H), 4.47 (d, J = 12.2 Hz, 1H), 4.30 (t, J = 5.5 Hz, 1H), 4.0–3.0 (m, 2H), 2.44 (br s, 1H, ex with D2O), 2.10 (s, 3H), 1.49 (s, 3H), 1.30 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.2, 113.5, 104.4, 87.0, 81.5, 75.5, 64.4, 62.2, 26.8, 26.6, 20.7 ppm. HRMS: m/z calcd for C11H17ClO6Na [M+Na]+ 303.0611; found 303.0612. 4.9.2. 3-C-(Acetyloxy)methyl-3-deoxy-3-fluoro-1,2-Oisopropylidene-a-D-xylofuranoside (12c) 0.37 g, 92% yield, thick liquid. [a]24 D +78.74 (c 0.62, CHCl3). IR (neat): mmax 3482 (br), 1742, 776 cm 1. 1H NMR (300 MHz, CDCl3): d 5.97 (d, J = 3.8 Hz, 1H), 4.63 (dd, J = 11.5, 3.8 Hz, 1H), 4.56 (dd, J = 19.6, 12.8 Hz, 1H), 4.26 (dd, J = 27.6, 12.8 Hz, 1H), 4.22 (dt, J = 25.8, 5.7 Hz, 1H), 3.94–3.82 (m, 2H), 2.16 (s, 3H), 2.0 (br s, 1H,

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ex with D2O), 1.52 (s, 3H), 1.35 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.3, 113.2, 104.4, 100.8 (d, J = 186.5 Hz), 83.1 (d, J = 35.7 Hz), 80.6 (d, J = 19.6 Hz), 62.0 (d, J = 19.6 Hz), 60.0 (d, J = 8.0 Hz), 26.9, 26.5, 20.7 ppm. HRMS: m/z calcd for C11H17FO6Na [M+Na]+ 287.0906; found 287.0920. 4.9.3. 3-C-(Acetyloxyethylamino)carbonyl-3-chloro-3-deoxy1,2-O-isopropylidene-a-D-xylofuranoside (13c) 0.85 g, 86% yield (over 2 steps), thick liquid. [a]27 D +57.85 (c 0.51, CHCl3); IR (neat): mmax 3347, 1733, 1671, 1234, 1048 cm 1. 1H NMR (300 MHz, CDCl3): d 7.44 (br s, 1H, ex with D2O), 5.93 (d, J = 3.5 Hz, 1H), 4.85 (d, J = 3.5 Hz, 1H), 4.70 (dd, J = 7.1, 4.7 Hz, 1H), 4.22 (t, J = 5.3 Hz, 2H), 4.10–3.85 (m, 2H, after D2O ex two dd one at 4.0 d J = 11.4, 6.6 Hz, another at 3.93 d J = 11.4, 4.7 Hz), 3.70–3.40 (m, 3H, with D2O ex integration comes for 2 protons), 2.08 (s, 3H), 1,55 (s, 3H), 1.36 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 171.0, 165.0, 113.5, 103.5, 87.1, 79.5, 75.4, 62.1, 60.4, 39.0, 26.4 (high intensity), 20.5 ppm. HRMS: m/z calcd for C13H20ClNO7Na [M+Na]+ 360.0825; found 360.0839. 4.9.4. 3-C-(Acetyloxyethylamino)carbonyl-3-deoxy-3-fluoro1,2-O-isopropylidene-a-D-xylofuranoside (14c) 1.25 g, 81% yield, thick liquid. [a]29 D +75.11 (c 0.4, CHCl3). IR (neat): mmax 3433 (br), 1734, 1676, 1070, 1030, 875 cm 1. 1H NMR (300 MHz, CDCl3): d 6.95 (br s, 1H, ex with D2O), 6.01 (d, J = 3.8 Hz, 1H), 4.76 (dt, J = 27.6, 6.2 Hz, 1H), 4.65 (dd, J = 14.3, 3.8 Hz, 1H), 4.30–4.10 (m, 2H), 3.82 (dd, J = 11.4, 6.2 Hz, 1H), 3.82 (dd, J = 11.4, 6.2 Hz, 1H), 3.66–3.54 (m, 2H), 2.5–1.9 (br s, 1H, ex with D2O), 2.08 (s, 3H), 1.59 (s, 3H), 1.35 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 171.1, 164.9 (d, J = 21.6 Hz), 113.9, 105.0, 100.0 (d, J = 194 Hz), 84.3 (d, J = 37.6 Hz), 81.0 (d, J = 19.4 Hz), 62.6, 58.8 (d, J = 7.7 Hz), 38.7, 26.8, 26.5, 20.7 ppm. HRMS: m/z calcd for C13H21FNO7 [M+H]+ 322.1302; found 322.12. 4.10. General procedure for synthesis of compounds 11d, 12d, 13d, 14d To a stirred solution of alcohol 11c, 12c, 13c, 14c (1 mmol) in dry DCM (5 mL), dry pyridine (3.5 mmol) was added at 10 °C. To this reaction mixture triflic anhydride (1.5 mmol) was added and stirred for 1 h at the same temperature. (Rf = 0.6, hexane/ethyl acetate 8:2). Reaction mixture was quenched with dilute CuSO4 (dissolved in H2O) solution and compound was extracted with DCM (3  20 mL). Combined organic layer was dried over Na2SO4 and concentrated in vacuum. The crude compound was subjected to the next reaction as it is. To a stirred solution of triflate compound (1 mmol) in dry DMF (5 mL), catalytic amounts of TBAI (0.01 mmol), and sodium azide (3 mmol) were added at rt and stirred for 1 h. (Rf = 0.7, hexane/ ethyl acetate 9:1). Reaction mixture was diluted with water, and compound was extracted with ethyl acetate. Combined organic layers were washed with water, brine, dried over Na2SO4, and concentrated in vacuum. The crude compound was purified by column chromatography on silica gel using EtOAc/hexane. 4.10.1. 3-C-(Acetyloxy)methyl-5-azido-3-chloro-3,5-di-deoxy1,2-O-isopropylidene-a-D-xylofuranoside (11d) 1.5 g, 86% yield (over two steps), thick liquid. [a]28 D +4.05 (c 0.66, CHCl3); IR (neat): mmax 2103, 1747, 872 cm 1. 1H NMR (300 MHz, CDCl3): d 5.96 (d, J = 3.6 Hz, 1H), 4.70 (d, J = 3.6 Hz, 1H), 4.52 (d, J = 12.0 Hz, 1H), 4.45 (d, J = 12.0 Hz,1H), 4.25 (dd, J = 12.9, 7.3 Hz, 1H), 3.68 (dd, J = 12.9, 7.3 Hz, 1H), 3.52 (dd, J = 12.9, 4.7 Hz, 1H), 2.14 (s, 3H), 1.53 (s, 3H), 1.34 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.0, 113.6, 104.4, 86.5, 80.0, 75.5, 64.2, 51.3, 26.7, 26.5, 20.6 ppm. HRMS: m/z calcd for C11H16ClN3O5Na [M+Na]+ 328.0675; found 328.0684.

4.10.2. 3-C-(Acetyloxy)methyl-5-azido-3,5-dideoxy-3-fluoro1,2-O-isopropylidene-a-D-xylofuranoside (12d) 0.48 g, 90% yield (over two steps), thick liquid. [a]28 D +10.67 (c 1.47, CHCl3). IR (neat): mmax 2102(s), 1746 cm 1. 1H NMR (300 MHz, CDCl3): d 5.99 (d, J = 3.8 Hz, 1H), 4.63 (dd, J = 11.0, 3.8 Hz, 1H), 4.49 (dd, J = 20, 12.5 Hz, 1H), 4.38 (dd, J = 27.1, 12.5 Hz, 1H), 4.19 (ddd, J = 12.4, 7.1, 5.2 Hz, 1H), 3.64 (ddd, J = 12.6, 7.1, 1.5 Hz, 1H), 3.52 (dd, J = 12.6, 5.2 Hz, 1H), 2.14 (s, 3H), 1.52 (s, 3H), 1.35 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 170.1, 113.3, 104.4, 100.6 (d, J = 187.7 Hz), 82.8 (d, J = 35.7 Hz), 79.1 (d, J = 19.6 Hz), 61.9 (d, J = 19.6 Hz), 49.1 (d, J = 8.0 Hz), 26.8, 26.4, 20.6. HRMS: m/z calcd for C11H16FN3O5Na [M+Na]+ 312.0971, found 312.0980. 4.10.3. 3-C-(Acetyloxyethylamino)carbonyl-5-azido-3-chloro3,5-dideoxy-1,2-di-O-isopropylidene-a-D-xylofuranoside (13d) 0.73 g, 90% yield (over 2 steps) thick liquid. [a]28 D +15.24 (c 0.59, CHCl3). IR (neat): mmax 3347, 2100, 1737, 1667, 1536, 1228, 1013, 751 cm 1. 1H NMR (300 MHz, CDCl3): d 6.76 (br s, 1H, ex with D2O), 6.01 (d, J = 3.6 Hz, 1H), 4.86 (dd, J = 7.1, 5.3 Hz, 1H), 4.73 (d, J = 3.6 Hz, 1H), 4.22 (t, J = 5.3 Hz, 2H), 3.62–3.52 (m, 4H), 2.08 (s, 3H), 1.56 (s, 3H), 1.34 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 171.0, 164.4, 114.0, 104.6, 87.2, 79.2, 74.7, 62.3, 50.8, 39.3, 26.7, 26.4, 20.6 ppm. HRMS: m/z calcd for C13H19ClN4O6Na [M+Na]+ 385.0890; found 385.0895. 4.10.4. 3-C-(Acetyloxyethylamino)carbonyl-5-azido-3,5dideoxy-3-fluoro-1,2-O-isopropylidene–a-D-xylofuranoside (14d) 0.87 g, 82% yield, thick liquid. [a]28 D +39.45 (c 0.7, CHCl3). IR (neat): mmax 3365, 2106, 1737, 1693 1030, 875 cm 1. 1H NMR (300 MHz, CDCl3): d 6.91 (br s, 1H, ex with D2O), 6.04 (d, J = 3.8 Hz, 1H), 4.85 (dt, J = 26.6, 6.1 Hz, 1H), 4.65 (dd, J = 14.3, 3.8 Hz, 1H), 4.32–4.10 (m, 2H), 3.72–3.50 (m, 3H), 3.41 (dd, J = 12.8, 6.1 Hz, 1H), 2.08 (s, 3H), 1.58, 1.35 ppm. 13C NMR (CDCl3, 75 MHz): d 170.7, 163.6 (d, J = 21.5 Hz), 113.7, 104.8, 100 (d, J = 266.5 Hz), 84.1 (d, J = 37.6 Hz), 79.1 (d, J = 19.9 Hz), 62.3, 47.7 (d, J = 7.8 Hz), 38.4, 26.5, 26.1, 20.3 ppm. HRMS: m/z calcd for C13H18FN4O6 [M H] 345.1211; found 345.1165. 4.11. General procedure for the synthesis of compounds 11e, 12e, 13e, 14e Compounds (11d, 12d, 13d, 14d 0.2 g) were dissolved in (5:1) TFA, water (4 mL) and stirred at 0 °C for 30 min, the reaction mixture was allowed to attain rt and stirred for 2 h. Then an additional amount of TFA (1 mL for 0.2 g) was added, and the reaction mixture was stirred at the same temperature for 12 h. The TFA was removed under reduced pressure, the compound dissolved in toluene (2  5 mL) and toluene removed in vacuum. Compound was purified by column chromatography using CHCl3/MeOH. 4.11.1. 3-C-(Acetyloxy)methyl-3-chloro-1,5-imino-1,3,5trideoxy-D-xylonolactam (11e) 0.11 g, 72% yield, sticky solid. [a]30 D +20.06 (c 0.5, CHCl3). IR (neat): mmax 3364, 1731, 1651, 1048, 802. 1H NMR (D2O + CD3OD, 300 MHz): d 4.54 (d, J = 11.2 Hz, 1H), 4.44 (d, J = 11.2 Hz, 1H), 4.32–4.27 (m, 2H), 3.55 (dd, J = 12.4, 6.2 Hz, 1H), 3.28 (dd, J = 12.4, 8.2 Hz, 1H), 2.0 (s, 3H) ppm. 13C NMR (D2O + CD3OD, 75 MHz): d 171.2, 170.1, 72.6, 72.2, 68.4, 61.5, 45.1, 19.2 ppm. HRMS: m/z calcd for C8H12ClNO5Na [M+Na]+ 260.0301; found 260.0313. 4.11.2. 3-C-(Acetyloxy)methyl-3-fluoro-1,5-imino-1,3,5trideoxy-D-xylonolactam (12e) 0.10 g, 70% yield, sticky solid. [a]30 D +10.72 (c 0.55, CHCl3). IR (neat): mmax 3341, 1732, 1648, 1052 cm 1. 1H NMR (D2O,

N. Bhuma et al. / Carbohydrate Research 402 (2015) 215–224

500 MHz): d 4.44 (dd, J = 11.6, 7.4 Hz, 1H), 4.38–4.24 (m, 3H), 3.48 (ddd, J = 12.6, 6.2, 3.4 Hz, 1H), 3.12 (dd, J = 12.6, 8.6 Hz, 1H), 1.97 (s, 3H) ppm. 13C NMR (D2O, 125 MHz): d 173.0, 172.0 (d, J = 10.0 Hz), 95.2 (d, J = 177 Hz), 69.6 (d, J = 23.7 Hz), 65.7 (d, J = 22.5 Hz), 59.1 (d, J = 38.7 Hz), 42.7 (d, J = 5.0 Hz), 20.0 ppm. HRMS: m/z calcd for C8H12FNO5Na [M+Na]+ 244.0597; found 244.0608. 4.11.3. 3-C-(Acetyloxyethylamino)carbonyl-3-chloro-1,5-imino1,3,5-trideoxy-D-xylonolactam (13e) 0.113 g, 70% yield. Sticky solid. [a]27 D +40.05 (c 0.34, MeOH). IR (neat): mmax 3341, 1726, 1659, 1536, 1242, 848 cm 1. 1H NMR (MeOH-d4, 300 MHz): d 4.26 (dd, J = 10.3, 6.6 Hz, 1H), 4.21–4.05 (m, 2H), 4.18 (s, 1H), 3.56–3.44 (m, 2H), 3.40 (dd, J = 11.4, 6.6 Hz, 1H), 3.21 (dd, J = 11.4, 10.3 Hz, 1H), 2.08 (s, 3H) ppm. 13C NMR (CDCl3, 75 MHz): d 173.1, 172.9, 168.2, 78.6, 75.0, 71.2, 63.6, 46.3, 40.0, 20.8 ppm. HRMS: m/z calcd for C10H16ClN2O6 [M+H]+ 295.0697; found 295.0697. 4.11.4. 3-C-(Acetyloxyethylamino)carbonyl-3-fluoro-1,5-imino1,3,5-trideoxy-D-xylonolactam (14e) 0.115 g, 72% yield, sticky solid. [a]30 D +57.41 (c 0.3, CHCl3). IR (neat): mmax 3440–3385 (br), 1728 1674, 1145, 1017 cm 1. 1H NMR (D2O, 300 MHz): d 8.52 (br s, 1H, protan appeared as broad singlet propionately less integration value this could be due to the exchange with D2O, this integration diminishes with time) 4.56–4.42 (m, 1H), 4.48 (d, J = 15.8 Hz, 1H), 4.28–4.18 (m, 2H), 3.66–3.54 (m, 3H), 3.27 (ddd, J = 11.4, 10.3 Hz, 1H), 2.10 (s, 3H) ppm. 13C NMR (D2O, 75 MHz): d 174.2, 171.8 (d, J = 11.6 Hz), 167.2 (d, J = 24.3 Hz), 99.2 (d, J = 198.5 Hz), 69.7 (d, J = 20.5 Hz), 66.1 (d, J = 21.5 Hz), 63.0, 42.8 (d, J = 7.7 Hz), 37.7, 20.2 ppm. HRMS: m/z calcd for C10H14FN2O6 [M H] 277.0836; found 277.0791.

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4.12.3. 3-Chloro-3-C-hydroxyethylaminocarbonyl-1,5-imino1,3,5-trideoxy-D-xylonolactam (4a) 0.121 g, 71% yield, sticky solid. [a]25 D +35.71 (c 0.14, MeOH). IR (neat): mmax 3437–3390 (br), 1676, 1139, 1027, 840, 723 cm 1. 1H NMR (D2O, 300 MHz): d 4.47 (dd, J = 10.0, 6.7 Hz, 1H), 4.44 (s, 1H), 3.68 (t, J = 5.2 Hz, 2H), 3.57 (dd, J = 11.6, 6.7 Hz, 1H), 3.48– 3.32 (m, 2H), 3.16 (br t, J = 11.6 Hz, 1H) ppm. 13C NMR (D2O, 75 MHz): d 172.0, 166.8, 77.4, 73.0, 69.1, 59.6, 44.0, 42.0 ppm. HRMS: m/z calcd for C8H14ClN2O5 [M+H]+ 253.0591; found 253.0592. 4.12.4. 3-Fluoro-3-C-hydroxyethylaminocarbonyl-1,5-imino1,3,5-trideoxy-D-xylonolactam (4b) 0.123 g, 75% sticky solid. [a]29 D +44.30 (c 0.65, CHCl3). IR (neat): mmax 3433–3390 (br), 1678–1140, 1017 cm 1. 1H NMR (D2O, 500 MHz): d 8.32 (s, 1H, NH br, NH protan appeared as broad singlet propionately less integration value this could be due to the exchange with D2O, this integration diminishes with time), 4.56– 4.42 (m, 1H), 4.48 (d, J = 15.4 Hz, 1H), 3.70 (t, J = 5.7 Hz, 2H), 3.58 (ddd, J = 11.3, 7.1, 2.7 Hz, 1H), 3.49–3.39 (m, 2H), 3.26 (br t, J = 11.3, 10 Hz, 1H). 13C NMR (D2O, 125 MHz): d 171.8, 167.2 (d, J = 23.7 Hz), 99.3 (d, J = 198.7 Hz), 69.8 (d, J = 20.0 Hz), 66.2 (d, J = 21.2 Hz), 59.8, 42.8 (d, J = 7.3 Hz), 41.2 ppm. HRMS: m/z calcd for C8H13FN2O5Na [M+Na]+ 259.0705; found 259.0712. Acknowledgments We are thankful to Department of Science, and Technology, New Delhi (Project File No. SR/S1/OC-20/2010) for financial support. N.B. thanks to UGC, New Delhi for Junior Research Fellowship, and M.V. for Dr. D.S. Kothari postdoctoral fellowship. We are also thankful to Prof. M.S. Wadia for helpful discussion.

4.12. General procedure for synthesis of compunds 3a, 3b, 4a, 4b

Supplementary data

Procedure: compounds (11e, 12e,13e, 14e 0.2 g), were dissolved in TFA (4 mL) and stirred at 0 °C for 30 min, the reaction mixture was allowed to attain rt and stirred for 12 h. The TFA was removed under reduced pressure and the compound dissolved in toluene (2  5 mL) and toluene removed under vacuum. Compound was purified by column chromatography using CHCl3/MeOH.

Supplementary data (the copies of NMR spectra of prepared compounds) associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.carres.2014.10.023.

4.12.1. 3-Chloro-3-C-hydroxymethyl-1,5-imino-1,3,5-trideoxy(3a) 0.11 g, 72% yield, sticky solid. [a]30 D +3.85 (c 1.1, CHCl3). IR (neat): mmax 3330, (br), 1642, 1020 cm 1. 1H NMR (D2O + CD3OD, 300 MHz): d 4.41 (s, 1H), 3.91 (d, J = 12.2 Hz, 1H), 3.52 (d, J = 12.2 Hz, 1H), 3.48–3.36 (m, 2H), 3.16 (d, J = 11.7 Hz, 1H) ppm. 13 C NMR (CD3OD, 75 MHz): d 171.2, 68.7, 63.8, 60.8, 54.5, 40.3 ppm. HRMS: m/z calcd for C6H11ClNO4 [M+H]+ 196.0376; found 196.0386. D-xylonolactam

4.12.2. 3-Fluoro-3-C-hydroxymethyl-1,5-imino-1,3,5-trideoxy(3b) 0.11 g, 74% yield, sticky solid. [a]30 D +3.08 (c 0.5, CHCl3). IR (neat): mmax 3334, (br), 1645, 1015 cm 1. 1H NMR (D2O, 300 MHz): d 7.3–6.8 (s, 1H, NH br, NH proton appeared as broad singlet propionately less integration value this could be due to the exchange with D2O, this integration diminishes with time), 4.32–4.08 (m, 2H), 3.81 (t, J = 12.4 Hz, 1H), 3.77 (dd, J = 12.4, 19.5 Hz, 1H), 3.52–3.36 (m, 1H), 3.15 (dd, J = 12.9, 7.2 Hz, 1H) ppm. 13C NMR (D2O, 75 MHz): d 172.4, 96.0 (d, J = 177.4 Hz), 69.9 (d, J = 26.5 Hz), 65.6 (d, J = 25.4 Hz), 58.6 (d, J = 28.8 Hz), 43.2 (d, J = 6.9 Hz) ppm. HRMS: m/z calcd for C6H11FNO4 [M+H]+ 180.0672; found 180.0683. D-xylonolactam

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