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N-(3-aminopropyl)subergorgamide, a new alkaloid from the gorgonian Paraplexaura sp. a
a
a
a
a
Fen Liu , Shuo Li , Zhi-Ran Ju , Ting-Ting Liu , Rui-Yu Liang , Xiaoa
a
Jian Liao & Shi-Hai Xu a
Department of Chemistry, Jinan University, Guangzhou 510632, China Published online: 03 Mar 2015.
Click for updates To cite this article: Fen Liu, Shuo Li, Zhi-Ran Ju, Ting-Ting Liu, Rui-Yu Liang, Xiao-Jian Liao & ShiHai Xu (2015): N-(3-aminopropyl)subergorgamide, a new alkaloid from the gorgonian Paraplexaura sp., Journal of Asian Natural Products Research, DOI: 10.1080/10286020.2015.1009049 To link to this article: http://dx.doi.org/10.1080/10286020.2015.1009049
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Journal of Asian Natural Products Research, 2015 http://dx.doi.org/10.1080/10286020.2015.1009049
N-(3-aminopropyl)subergorgamide, a new alkaloid from the gorgonian Paraplexaura sp. Fen Liu, Shuo Li, Zhi-Ran Ju, Ting-Ting Liu, Rui-Yu Liang, Xiao-Jian Liao and Shi-Hai Xu* Department of Chemistry, Jinan University, Guangzhou 510632, China
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(Received 24 October 2014; final version received 13 January 2015) A new alkaloid named N-(3-aminopropyl)subergorgamide (1), along with nine known nitrogen-containing compounds (2 – 10), was isolated from the organic extract of gorgonian Paraplexaura sp. collected from Zhanjiang in Naozhou Island, South China Sea. Their structures were established by detailed MS and NMR spectroscopic analyses, as well as by comparison with literature data. Keywords: N-(3-aminopropyl)subergorgamide; gorgonian; Paraplexaura sp.; alkaloid
1. Introduction As a common species in the ocean, gorgonian is a rich source of structurally unique compounds, such as diterpenes, sesquiterpenes, sterols, alkaloids, and so on, and many of these metabolites have potential pharmaceutical applications [1]. Much attention was given to the alkaloids produced by gorgonian, which had broadspectrum activities involving antimicrobial, antitumor, antivirus, antihypertensive, blood coagulation, and hemolysis effects [2 –4]. The gorgonian Paraplexaura sp., belonging to the family Plexauridae, was systematically investigated by our research group for the first time, resulting in the discovery of a series of structurally unique compounds. Herein, this paper reports the isolation and characterization of one new alkaloid (1) and nine known nitrogen-containing compounds (2 – 10) from Paraplexaura sp. 2. Results and discussion The organic extract of the gorgonian Paraplexaura sp. was chromatographed on TLC, silical gel, Sephadex LH-20, and *Corresponding author. Email: [email protected] q 2015 Taylor & Francis
semi-preparative HPLC, respectively, then a new alkaloid named N-(3-aminopropyl) subergorgamide (1) and nine known nitrogen-containing compounds were isolated. Their structures were determined by spectroscopic analyses and by comparison with literature data. The structures of nine known nitrogen-containing compounds were identified as 1-(2-methyl-4-(2methylphenylazo)phenylazo)-2-naphthol (2) [5], 1,4-(dibutylamino)anthracene9,10-dione (3) [6],1-methylhydantoin (4) [7], pyrimidine-2,4(1H,3H)-dione (5) [8], 5-methylpyrimidine-2,4(1H,3H)-dione (6) [9], indole-3-carboxylic acid (7) [10], 1,3,7-trimethyl-1H-purine-2,6(3H,7H)dione1 (8) [11], N-2-(1,3-dihy-droxyoctadecan-4,8-dienyl)-hexadecamide (9) [12], and octadecanoic acid (2-hydroxy-ethyl)amide (10)[13]. Notably, it is the first report of metabolites 2 and 3 being naturally occurring compounds. Their structures are shown in Figure 1. The new compound 1 was obtained as a white solid. Its molecular formula was established as C18H28N2O2 by HR-ESIMS (m/z 305.2231 [M þ H]þ), suggesting six degrees of unsaturation. The 1H and
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O (CH2)13CH3
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Figure 1. Structures of compounds 1 –10. 13
C NMR spectra (Table 1), along with the DEPT and HSQC experiments of 1 displayed signals accounting for three methyl groups (dH/C 1.17/24.3, 1.10/17.7,
Table 1. Position 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
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and 1.07/20.0), one trisubstituted double bond (dH/C 5.82/141.6, dC 141.2), two carbonyl groups (dC 165.4, 218.3), and two amino groups (dH 6.92, 2.18). Based on six
H, 13C NMR spectra dataa, 1H– 1H COSY, and HMBC correlations of 1.
dH (ppm, J in Hz) 5.82 (s) 1.76– 1.79 (m), 1.59 – 1.62 (m) 1.63– 1.72 (m) 1.53– 1.58 (m) 2.11– 2.07 (m) 1.75– 1.72 (m) 2.32 (dd, 10.0, 6.5), 2.01 (dd, 10.0, 6.5) 3.06 (q, 7.1) 1.08 (q, 7.1) 1.10 (d, 7.2) 1.17 (s) 6.92 (t, 5.4) 3.41 (dd, 12.2, 5.4) 1.74– 1.71 (m) 2.87 (t, 6.3) 2.18 (s)
dC (ppm) 141.2 141.6 61.8 38.6 28.2 62.7 33.4 50.1 218.3 68.8 52.1 17.7 20.0 24.3 165.4 37.8 31.0 39.9
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H-5 H-4, 6 H-5, 7 H-6, 8, 13 H-7
C-2, 6, 10 C-7 C-3, 4, 11, 13 C-8, 13 C-6, 10, 9 C-7, 13
H-12 H-11
C-1, 3, 10, 12 C-1, 10, 11 C-6, 7, 8 C-1, 3, 4, 10
H-17 H-18 H-17, 19 H-18
a Bruker-DRX-500 spectrometer (500 MHz for 1H and 125 MHz for deduced from analysis of 1D and 2D spectra.
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C-15, 18, 19 C-17, 19 C-17, 18
C NMR) in CDCl3; assignments were
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Journal of Asian Natural Products Research
The relative configuration of compound 1 was determined by comparison of chemical shifts and coupling constants of 1 with those of subergorgic acid [14,15], as well as on the basis of NOESY experiment. As shown in Figure 3, the NOESY correlations of H-11 with H-13 and H-6 indicated that H-11, H-13, and H-6 were in the same side, while H-7 was in the other side. Therefore, the relative configuration of 1 was established. The absolute configuration of compound 1 was deduced as shown in Figure 1 by comparing the optical rotations with its parent compound (-)-subergorgic acid {compound 1: [a ]25 D 2 71.8 (c ¼ 0.05, MeOH); subergorgic acid:[a ]28 D 2 61 (c ¼ 0.1, MeOH) [16]}.
unsaturation degrees revealed by the molecular formula, 1 apparently should contain three rings except for two carbonyl groups and one double bond. Three fragments A, B, and D (Figure 2) were identified from the analyses of the 2D NMR data (1H – 1HCOSY, HSQC, and HMBC) (Table 1). Fragments A and B were linked to fragment C by the HMBC correlations of C-1 with H-14 and C-10 with H-2, 8, 12. The spectroscopic data of fragment C were similar to those of subergorgic acid [14,15]. Fragments C and D were linked to structure E by the HMBC correlation from H-17 to C-15. Thus, the planar structure of 1 was confirmed as structure E.
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Figure 2. Key 1H– 1H COSY and HMBC correlations of compound 1.
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Figure 3. Key NOESY correlations of compound 1.
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3. Experimental 3.1 General and experimental procedures Optical rotations were measured on an Anton Paar MCP-500 polarimeter (Anton Paar, Graz, Austria). UV spectra were recorded on a TU-1900 spectrophotometer (Beijing Purkinje General Instrument Co., Beijing, China). IR spectra were obtained on a Thermo Nicolet 6700 spectrometer with KBr disks (Thermo, Waltham, American). NMR spectra were measured on a Bruker Avance 500 MHz NMR spectrometer (Bruker, Fa¨llanden, Switzerland) with TMS as internal standard. ESIMS were recorded on an ABI 4000 Q-Trap mass spectrometer (Applied Biosystems, Foster City, American). High-resolution ESI-MS were recorded at 70 eV and 200?C on a Finnigan-MAT-95XL mass spectrometer (ThermoQuest Finnigan, Bremen, Germany). Semi-preparative reversed-phase HPLC (Rp-C18; MeOH/ H2O; flow rate: 2 ml/min) was performed on an Agilent 1200 series apparatus (Agilent, Palo Alto, American). Column chromatography was performed with silica gel (200 – 300 mesh, Qingdao Haiyang Chemical Co., Qingdao, China) and Sephadex LH-20 (Pharmacia, New Jersey, American). TLC was carried out with precoated silica gel plates (GF-254, Qingdao Haiyang Chemical Co., Qingdao, China). All solvents were of analytical grade.
3.2 Organism The gorgonian Paraplexaura sp. was collected at Zhanjiang in Naozhou Island, South China Sea, China, in July 2011. The species was identified by Professor Rob Van Soest (National Museum of National History Naturalis, The Netherlands) and a voucher specimen (2011 – 03) had been deposited at the Laboratory of Natural Product of the Department Chemistry of Jinan University, Guangzhou, China.
3.3 Extraction and isolation The gorgonian Paraplexaura sp. specimen (12.1 kg, wet weight) was dried and cut into small pieces, followed by extract with ethanol at room temperature for 10 days £ 3 and in CHCl3/CH3OH (1:1, V/V) for 15 days £ 2. The combined extract was filtered, and the solvent was removed under reduced pressure to yield black gum (128 g). The resulting residue was partitioned between H2O and EtOAc. The EtOAc fraction was separated on a silica gel column with solvents of increasing polarity from petroleum ether (PE)/EtOAc through EtOAc/MeOH to MeOH/H2O mixtures which furnished 10 fractions. Fraction I (19.8 g) eluted with 10% EtOAc/PE was further purified by semi-preparative reverse HPLC (C18, 250 mm £ 9.4 mm, 5 mm, 2 ml/min) using isocratic MeOH/H2O (8:2) to yield compounds 2 (2.0 mg, retention time: 28.7 min) and 3 (10 mg, retention time: 35.6 min). Fraction II (14.5 g) eluted with 30% EtOAc/PE was further recrystallized from MeOH to afford compound 4 (7.2 mg). Fraction IV (9.6 g) eluted with 70% EtOAc/ PE was further purified by semi-preparative reverse HPLC using isocratic MeOH/H2O (7:3) to yield compound 9 (126.0 mg, retention time: 19.4 min). Fraction VI (8.2 g) eluted with 100% EtOAc and fraction VII (7.8 g) eluted with 10% MeOH/EtOAc were further purified by Sephadex LH-20 (50% CHCl3/CH3OH) to yield compounds 5 (16.5 mg), 6 (6.3 mg), 7 (2.1 mg), 8 (3.6 mg), and 10 (4.8 mg), respectively. The new compound 1 (2.2 mg), afforded from fraction VII, was also purified by Sephadex LH20 (50% CHCl3/CH3OH). 3.3.1 N-(3-aminopropyl) subergorgamide (1) White solid; [a ]25 D 2 71.8 (c ¼ 0.05, MeOH); UV (MeOH): lmax 217 nm; IR (KBr) nmax: 3402, 2926, 2866, 1723, 1654, 1617, 1534, 1453, and 1380 cm21; for 1H NMR (CDCl3, 500 MHz) and 13C NMR (CDCl3, 125 MHz) spectral data, see
Journal of Asian Natural Products Research Table 1; HR-ESI-MS: m/z 305.2231 [M þ H]þ (calcd for C 18H 29 N2 O 2, 305.2229). Funding
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This research work was financially supported by the National Natural Science Foundation of China [grant number 21172094], [grant number 41376155], [grant number 21372100], and [grant number U1301131]; the National High Technology Development Project [863 Project, grant number 2013AA092902]; and Science and Technology Program of Guangzhou, China [grant number 2013000000163].
Disclosure statement No potential conflict of interest was reported by the authors.
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[6] S.M. Nor, M.A.H. Sukari, S.S.S. Azziz, W.C. Fah, H. Alimon, and F. Juhan, Molecules 18, 8046 (2013). doi:10.3390/ molecules18078046. [7] W. Balansa, R. Islam, D.F. Gilbert, F. Fontaine, X. Xiao, H. Zhang, A.M. Piggott, J.W. Lynch, and J. Capon, Bioorg. Med. Chem. 21, 4420 (2013). doi:10.1016/j.bmc.2013.04.061. [8] H. Roohi and R. Nokhostin, Struct. Chem. 25, 483– 493 (2014). doi:10.1007/s11224013-0264-7. [9] M. Dracˇ´ınsky´ and P. Hodgkinson, CrystEngComm 15, 8705 (2013). doi:10.1039/ c3ce40612a. [10] E.B. Yang, L.P. Ma, J.H. Wang, and Y. Ye, Chin. J. Magn. Reson. 30, 256 (2013). [11] F. Khallouki, R. Haubner, W.E. Hull, G. Erben, B. Spiegelhalder, H. Bartsch, and R.W. Owen, Food Chem. Toxicol. 45, 472 (2007). doi:10.1016/j.fct.2006.09. 011. [12] C.W. Lin, J.Y. Su, L.M. Zeng, W.X. Wei, and Y. Wei, Chin. J. Org. Chem. 25, 225 (2005). [13] L.P. Guan, D.H. Zhao, J.H. Xiu, X. Sui, H.R. Piao, and Z.S. Quan, Arch. Pharm. Chem. Life Sci. 342, 34 (2009). doi:10. 1002/ardp.200800153. [14] B.H. Chen, K.F. Jiao, Q.E. Ji, H.Q. Song, and R. Feng, Chin. Sci. Bull. 2, 142 (1990). [15] G.D. Reddy, D.R.S. Reddy, A. Razzack, and K. Balaji, Asian J. Chem. 23, 816 (2011). [16] G.H. Wang, A.F. Ahmed, Y.H. Kuo, and H. Sheu, J. Nat. Prod. 65, 1033 (2002). doi:10.1021/np0106586.
Journal of Asian Natural Products Research Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ganp20
N-(3-aminopropyl)subergorgamide, a new alkaloid from the gorgonian Paraplexaura sp. a
a
a
a
a
Fen Liu , Shuo Li , Zhi-Ran Ju , Ting-Ting Liu , Rui-Yu Liang , Xiaoa
a
Jian Liao & Shi-Hai Xu a
Department of Chemistry, Jinan University, Guangzhou 510632, China Published online: 03 Mar 2015.
Click for updates To cite this article: Fen Liu, Shuo Li, Zhi-Ran Ju, Ting-Ting Liu, Rui-Yu Liang, Xiao-Jian Liao & ShiHai Xu (2015): N-(3-aminopropyl)subergorgamide, a new alkaloid from the gorgonian Paraplexaura sp., Journal of Asian Natural Products Research, DOI: 10.1080/10286020.2015.1009049 To link to this article: http://dx.doi.org/10.1080/10286020.2015.1009049
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &
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Journal of Asian Natural Products Research, 2015 http://dx.doi.org/10.1080/10286020.2015.1009049
N-(3-aminopropyl)subergorgamide, a new alkaloid from the gorgonian Paraplexaura sp. Fen Liu, Shuo Li, Zhi-Ran Ju, Ting-Ting Liu, Rui-Yu Liang, Xiao-Jian Liao and Shi-Hai Xu* Department of Chemistry, Jinan University, Guangzhou 510632, China
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(Received 24 October 2014; final version received 13 January 2015) A new alkaloid named N-(3-aminopropyl)subergorgamide (1), along with nine known nitrogen-containing compounds (2 – 10), was isolated from the organic extract of gorgonian Paraplexaura sp. collected from Zhanjiang in Naozhou Island, South China Sea. Their structures were established by detailed MS and NMR spectroscopic analyses, as well as by comparison with literature data. Keywords: N-(3-aminopropyl)subergorgamide; gorgonian; Paraplexaura sp.; alkaloid
1. Introduction As a common species in the ocean, gorgonian is a rich source of structurally unique compounds, such as diterpenes, sesquiterpenes, sterols, alkaloids, and so on, and many of these metabolites have potential pharmaceutical applications [1]. Much attention was given to the alkaloids produced by gorgonian, which had broadspectrum activities involving antimicrobial, antitumor, antivirus, antihypertensive, blood coagulation, and hemolysis effects [2 –4]. The gorgonian Paraplexaura sp., belonging to the family Plexauridae, was systematically investigated by our research group for the first time, resulting in the discovery of a series of structurally unique compounds. Herein, this paper reports the isolation and characterization of one new alkaloid (1) and nine known nitrogen-containing compounds (2 – 10) from Paraplexaura sp. 2. Results and discussion The organic extract of the gorgonian Paraplexaura sp. was chromatographed on TLC, silical gel, Sephadex LH-20, and *Corresponding author. Email: [email protected] q 2015 Taylor & Francis
semi-preparative HPLC, respectively, then a new alkaloid named N-(3-aminopropyl) subergorgamide (1) and nine known nitrogen-containing compounds were isolated. Their structures were determined by spectroscopic analyses and by comparison with literature data. The structures of nine known nitrogen-containing compounds were identified as 1-(2-methyl-4-(2methylphenylazo)phenylazo)-2-naphthol (2) [5], 1,4-(dibutylamino)anthracene9,10-dione (3) [6],1-methylhydantoin (4) [7], pyrimidine-2,4(1H,3H)-dione (5) [8], 5-methylpyrimidine-2,4(1H,3H)-dione (6) [9], indole-3-carboxylic acid (7) [10], 1,3,7-trimethyl-1H-purine-2,6(3H,7H)dione1 (8) [11], N-2-(1,3-dihy-droxyoctadecan-4,8-dienyl)-hexadecamide (9) [12], and octadecanoic acid (2-hydroxy-ethyl)amide (10)[13]. Notably, it is the first report of metabolites 2 and 3 being naturally occurring compounds. Their structures are shown in Figure 1. The new compound 1 was obtained as a white solid. Its molecular formula was established as C18H28N2O2 by HR-ESIMS (m/z 305.2231 [M þ H]þ), suggesting six degrees of unsaturation. The 1H and
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O (CH2)13CH3
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Figure 1. Structures of compounds 1 –10. 13
C NMR spectra (Table 1), along with the DEPT and HSQC experiments of 1 displayed signals accounting for three methyl groups (dH/C 1.17/24.3, 1.10/17.7,
Table 1. Position 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
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and 1.07/20.0), one trisubstituted double bond (dH/C 5.82/141.6, dC 141.2), two carbonyl groups (dC 165.4, 218.3), and two amino groups (dH 6.92, 2.18). Based on six
H, 13C NMR spectra dataa, 1H– 1H COSY, and HMBC correlations of 1.
dH (ppm, J in Hz) 5.82 (s) 1.76– 1.79 (m), 1.59 – 1.62 (m) 1.63– 1.72 (m) 1.53– 1.58 (m) 2.11– 2.07 (m) 1.75– 1.72 (m) 2.32 (dd, 10.0, 6.5), 2.01 (dd, 10.0, 6.5) 3.06 (q, 7.1) 1.08 (q, 7.1) 1.10 (d, 7.2) 1.17 (s) 6.92 (t, 5.4) 3.41 (dd, 12.2, 5.4) 1.74– 1.71 (m) 2.87 (t, 6.3) 2.18 (s)
dC (ppm) 141.2 141.6 61.8 38.6 28.2 62.7 33.4 50.1 218.3 68.8 52.1 17.7 20.0 24.3 165.4 37.8 31.0 39.9
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H-5 H-4, 6 H-5, 7 H-6, 8, 13 H-7
C-2, 6, 10 C-7 C-3, 4, 11, 13 C-8, 13 C-6, 10, 9 C-7, 13
H-12 H-11
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H-17 H-18 H-17, 19 H-18
a Bruker-DRX-500 spectrometer (500 MHz for 1H and 125 MHz for deduced from analysis of 1D and 2D spectra.
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C-15, 18, 19 C-17, 19 C-17, 18
C NMR) in CDCl3; assignments were
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Journal of Asian Natural Products Research
The relative configuration of compound 1 was determined by comparison of chemical shifts and coupling constants of 1 with those of subergorgic acid [14,15], as well as on the basis of NOESY experiment. As shown in Figure 3, the NOESY correlations of H-11 with H-13 and H-6 indicated that H-11, H-13, and H-6 were in the same side, while H-7 was in the other side. Therefore, the relative configuration of 1 was established. The absolute configuration of compound 1 was deduced as shown in Figure 1 by comparing the optical rotations with its parent compound (-)-subergorgic acid {compound 1: [a ]25 D 2 71.8 (c ¼ 0.05, MeOH); subergorgic acid:[a ]28 D 2 61 (c ¼ 0.1, MeOH) [16]}.
unsaturation degrees revealed by the molecular formula, 1 apparently should contain three rings except for two carbonyl groups and one double bond. Three fragments A, B, and D (Figure 2) were identified from the analyses of the 2D NMR data (1H – 1HCOSY, HSQC, and HMBC) (Table 1). Fragments A and B were linked to fragment C by the HMBC correlations of C-1 with H-14 and C-10 with H-2, 8, 12. The spectroscopic data of fragment C were similar to those of subergorgic acid [14,15]. Fragments C and D were linked to structure E by the HMBC correlation from H-17 to C-15. Thus, the planar structure of 1 was confirmed as structure E.
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Figure 2. Key 1H– 1H COSY and HMBC correlations of compound 1.
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Figure 3. Key NOESY correlations of compound 1.
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3. Experimental 3.1 General and experimental procedures Optical rotations were measured on an Anton Paar MCP-500 polarimeter (Anton Paar, Graz, Austria). UV spectra were recorded on a TU-1900 spectrophotometer (Beijing Purkinje General Instrument Co., Beijing, China). IR spectra were obtained on a Thermo Nicolet 6700 spectrometer with KBr disks (Thermo, Waltham, American). NMR spectra were measured on a Bruker Avance 500 MHz NMR spectrometer (Bruker, Fa¨llanden, Switzerland) with TMS as internal standard. ESIMS were recorded on an ABI 4000 Q-Trap mass spectrometer (Applied Biosystems, Foster City, American). High-resolution ESI-MS were recorded at 70 eV and 200?C on a Finnigan-MAT-95XL mass spectrometer (ThermoQuest Finnigan, Bremen, Germany). Semi-preparative reversed-phase HPLC (Rp-C18; MeOH/ H2O; flow rate: 2 ml/min) was performed on an Agilent 1200 series apparatus (Agilent, Palo Alto, American). Column chromatography was performed with silica gel (200 – 300 mesh, Qingdao Haiyang Chemical Co., Qingdao, China) and Sephadex LH-20 (Pharmacia, New Jersey, American). TLC was carried out with precoated silica gel plates (GF-254, Qingdao Haiyang Chemical Co., Qingdao, China). All solvents were of analytical grade.
3.2 Organism The gorgonian Paraplexaura sp. was collected at Zhanjiang in Naozhou Island, South China Sea, China, in July 2011. The species was identified by Professor Rob Van Soest (National Museum of National History Naturalis, The Netherlands) and a voucher specimen (2011 – 03) had been deposited at the Laboratory of Natural Product of the Department Chemistry of Jinan University, Guangzhou, China.
3.3 Extraction and isolation The gorgonian Paraplexaura sp. specimen (12.1 kg, wet weight) was dried and cut into small pieces, followed by extract with ethanol at room temperature for 10 days £ 3 and in CHCl3/CH3OH (1:1, V/V) for 15 days £ 2. The combined extract was filtered, and the solvent was removed under reduced pressure to yield black gum (128 g). The resulting residue was partitioned between H2O and EtOAc. The EtOAc fraction was separated on a silica gel column with solvents of increasing polarity from petroleum ether (PE)/EtOAc through EtOAc/MeOH to MeOH/H2O mixtures which furnished 10 fractions. Fraction I (19.8 g) eluted with 10% EtOAc/PE was further purified by semi-preparative reverse HPLC (C18, 250 mm £ 9.4 mm, 5 mm, 2 ml/min) using isocratic MeOH/H2O (8:2) to yield compounds 2 (2.0 mg, retention time: 28.7 min) and 3 (10 mg, retention time: 35.6 min). Fraction II (14.5 g) eluted with 30% EtOAc/PE was further recrystallized from MeOH to afford compound 4 (7.2 mg). Fraction IV (9.6 g) eluted with 70% EtOAc/ PE was further purified by semi-preparative reverse HPLC using isocratic MeOH/H2O (7:3) to yield compound 9 (126.0 mg, retention time: 19.4 min). Fraction VI (8.2 g) eluted with 100% EtOAc and fraction VII (7.8 g) eluted with 10% MeOH/EtOAc were further purified by Sephadex LH-20 (50% CHCl3/CH3OH) to yield compounds 5 (16.5 mg), 6 (6.3 mg), 7 (2.1 mg), 8 (3.6 mg), and 10 (4.8 mg), respectively. The new compound 1 (2.2 mg), afforded from fraction VII, was also purified by Sephadex LH20 (50% CHCl3/CH3OH). 3.3.1 N-(3-aminopropyl) subergorgamide (1) White solid; [a ]25 D 2 71.8 (c ¼ 0.05, MeOH); UV (MeOH): lmax 217 nm; IR (KBr) nmax: 3402, 2926, 2866, 1723, 1654, 1617, 1534, 1453, and 1380 cm21; for 1H NMR (CDCl3, 500 MHz) and 13C NMR (CDCl3, 125 MHz) spectral data, see
Journal of Asian Natural Products Research Table 1; HR-ESI-MS: m/z 305.2231 [M þ H]þ (calcd for C 18H 29 N2 O 2, 305.2229). Funding
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This research work was financially supported by the National Natural Science Foundation of China [grant number 21172094], [grant number 41376155], [grant number 21372100], and [grant number U1301131]; the National High Technology Development Project [863 Project, grant number 2013AA092902]; and Science and Technology Program of Guangzhou, China [grant number 2013000000163].
Disclosure statement No potential conflict of interest was reported by the authors.
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