848
Specialia
EXPERIENTIA 33/7
f l - C a n n a b i s p i r a n o l : A n e w n o n - c a n n a b i n o i d p h e n o l f r o m C a n n a b i s s a t i v a L. ~ E. G. Boeren, M. A. Elsohly, C. E. T u r n e r 2 a n d C. A. S a l e m i n k 3
Research Institute o/ Pharmaceutical Sciences, School o/ Pharmacy, University of Mississippi, University (Mississippi 38677, USA), 6 December 1976 Summary. A n e t h a n o l e x t r a c t of C a n n a b i s s a t i v a L. a f f o r d e d u p o n p a r t i t i o n i n g a n d r e p e a t e d c h r o m a t o g r a p h y a n e w n o n - c a n n a b i n o i d p h e n o l [ 7 ' - h y d r o x y - 5 ' - m e t h o x y - s p i r o - (cyclohexane-1, l'-indan)-4/3-olJ(IIIa), n a m e d fl-cannabispiranol. C a n n a b i s p i r a n s t r u c t u r e (I) as d e t e r m i n e d b y X - r a y c r y s t a l l o g r a p h y 4 r e p r e s e n t e d a n e w class of c o m p o u n d s d i s c o v e r e d in c a n n a b i s . I n a p r e v i o u s c o m m u n i c a t i o n 5 we h a v e r e p o r t e d t h e isolation of c a n n a b i s p i r a n (I) a n d d e h y d r o c a n n a b i s p i r a n (II) f r o m an e t h a n o l i c e x t r a c t of a S o u t h African v a r i a n t of c a n n a b i s g r o w n in Mississippi. F u r t h e r e x a m i n a t i o n of t h e a b o v e e x t r a c t r e s u l t e d in t h e isolation of a n e w r e l a t e d c o m p o u n d 7 ' - h y d r o x y - 5 ' m e t h o x y - s p i r o - ( c y c l o h e x a n e - l , l ' - i n d a n ) - 4 f l - o l w h i c h we n a m e d f l - c a n n a b i s p i r a n o l ( I I I a ) . The s t r u c t u r e of I I I a is t h e s u b j e c t of t h i s r e p o r t . fl-cannabispiranol ( I I I a ) , m . p . 179-183~ R R T 0.326; C15Ha003 (M+. 248) was o p t i c a l l y inactive. The U V spect r u m s h o w e d p e a k s a t ,qMeOH 207 (log e 3.85) a n d 221 n m --max (3.82). The I R s p e c t r u m (KBr) s h o w e d b a n d s a t 3440
(OH), 3190 (OH), 2910 (CH), 2845 (OCH), 1625 and 1595 (C=CAr), b u t no c a r b o n y l a b s o r p t i o n . The 1 H N M R s h o w e d a singlet a t 63.60 (3H) (OCH3) , 2 a r o m a t i c p r o t o n s a t 66.10 (s) a n d 2 p r o t o n s a t 63.05 a n d 67.95 w h i c h were e x c h a n g e a b l e w i t h D20. Most i m p o r t a n t was a p e n t e t a t 63.98 (1H J : 3 H z ) assigned t o - C H O H - . T r e a t m e n t of I I I a w i t h acetic a n h y d r i d e in p y r i d i n e yielded a d i a c e t a t e ( I I I b ) , m . p . 127-128~ R R T 0.58; w h i c h s h o w e d I R b a n d s a t 1763 a n d 1731 c m -1 (arom a t i c a n d a l i p h a t i c a c e t a t e s respectively) 7. The m a s s s p e c t r u m s h o w e d p r o m i n e n t ions a t m / e 332 (16%)
(M+.) (for C19H2405); 290 (85%) ( M - H 2 C = C = O ) + . ; 272 (28%) (M-CH3COOH)+.; 230 (85%) ( M - H 2 C = C = O H3CCOOH)+.; 189 (61%); 187 (16~ a n d 176 (100%). I n a d d i t i o n t o t h e a c e t a t e m e t h y l s a t 62.10 (3H, s), 2.31 (3H, s), t h e 1 H N M R s h o w e d a p e n t e t a t 65.05 (1H) assigned to - C H O A c - . T h e s e d a t a s u g g e s t e d t h a t I I I a m i g h t be a d i h y d r o d e r i v a t i v e of c a n n a b i s p i r a n (I). This was p r o v e n t o be t h e case b y r e d u c t i o n of c a n n a b i s p i r a n w i t h N a B H 4 in M e O H w h i c h r e s u l t e d in t h e f o r m a t i o n of 2 isomeric p r o d u c t s in a 1:4 ratio (by GLC analysis) w i t h R R T 0.32 a n d 0.36. TLC of t h e r e a c t i o n p r o d u c t s h o w e d 2 s p o t s (Rf 0.43 a n d 0.55, CHC13-EtOAc, 1:1), t h e less polar of w h i c h was t h e m a j o r c o m p o n e n t . S e p a r a t i o n was a c h i e v e d b y c h r o m a t o g r a p h y on silica gel G
OH ~
R1
H3CO~ I
R1 +
R~ =
=
0
II IIIa
R1 + R2 = = o, Act, fltocarbonylgroup R1 =
OH,
IIIb
R1 =
OAc,
IVa
R1 =
Hb, R 2 =
OH
IVb
R1 =
Hb, R 2 =
OAe
R2 = R2 =
Ha Ha
R2
c o l u m n using t h e p r e v i o u s TLC s o l v e n t s y s t e m . T h e m o s t p o l a r isomer ( R R T 0.32, Rf 0.43) was f o u n d to be i d e n t i c a l w i t h t h e n a t u r a l p r o d u c t I I I a (TLC, m . p . , I R a n d MS). The i s o m e r I V a ( R R T 0.36) h a d m . p . 176~ and similar s p e c t r a l d a t a to I I I a . The 1 H N M R h o w e v e r , s h o w e d t h a t Ha was o v e r l a p p i n g w i t h t h e m e t h o x y signal. T h u s I r a was a c e t y l a t e d (acetic a n h y d r i d e in pyridine) t o give a d i a c e t a t e I V b , m . p . 85-86~ R R T 0.48 a n d v m a x (KBr) 1770 a n d 1735 c m -1. The 1 H N M R (CDC13) of I V b s h o w e d 2 a c e t a t e m e t h y l s a t 62.00 (3H, s) a n d 62.25 (3H, s) a n d m o s t i m p o r t a n t was a b r o a d m u l t i p l e t b e t w e e n 64.33 a n d 4.91 (1H) assigned t o t h e p r o t o n u n d e r t h e a c e t o x y g r o u p Hb. B a s e d on t h e ~ H N M R of I I I a a n d I r a and their acetates I I I b and I V b the hydroxyl group on t h e c y c l o h e x a n e ring of I I I a was assigned t h e axial p o s i t i o n a n d t h e h y d r o g e n Ha t h e e q u a t o r i a l position. T h e e q u a t o r i a l Ha couples w i t h t h e n e i g h b o r i n g axial a n d e q u a t o r i a l h y d r o g e n s w i t h t h e s a m e coupling c o n s t a n t r e s u l t i n g in a p e n t e t J = 3Hz. O n t h e o t h e r h a n d I V a w a s assigned an e q u a t o r i a l O H a n d axial H. T h e 1 H N M R of I V b s h o w e d p r o t o n Hb as a b r o a d m u l t i p l e t as a r e s u l t of coupling w i t h 2 axial p r o t o n s and 2 e q u a torial p r o t o n s on b o t h sides with d i f f e r e n t coupling constants. U p o n b u i l d i n g a D r e i d i n g m o d e l of I I I a a n d I r a it was f o u n d t h a t t h e molecules h a d a p l a n e of s y m m e t r y w h i c h bisects t h e i n d a n nucleus a n d w h i c h e x p l a i n s t h e optical i n a c t i v i t y of b o t h c o m p o u n d s . This is t h e first r e p o r t of f l - c a n n a b i s p i r a n o l in n a t u r e .
1 Acknowledgments. Supported by contract HSM-42-70-109 and grant DA-00928-01 from the National Institute on Drug Abuse as well as the Research Institute of Pharmaceutical Sciences. The authors are grateful to Mrs Glenda Lewis for running the GC analyses and to Dr Stephen Billets for running the Mass Spectra. Cannabis Herbarium specimens are stored in the Herbariunl, Department of Pharmacognosy, School of Pharmacy, University of Mississippi, USA. 2 To whom correspondence should be addressed. 3 Laboratory of Organic Chemistry, State University of Utrecht, the Netherlands. 4 T. Ottersen, A. Aasen, F. S. E1-Feraly and C. E. Turner, Chem. Comm. 1976, 580. 5 F. S. E1-Feraly, M. A. Elsohly, E. G. Boeren, C. E. Turner, T. Ottersen and A. Aasen, Tetrahedron, submitted for publication. 6 All gas chromatographic analyses were performed on a 2~o OV-17 column at 210 ~ using androst-4-ene-3,17-dione as the internal standard as described by C. E. Turner and K. Hadley, J. pharm. Sci. 62, 251 (1973). 7 K. Nakanishi, in: Infrared Absorption Spectl'oseopy-Pratical, p. 42. Holden-Day Inc., San Francisco 1962.
Specialia
EXPERIENTIA 33/7
f l - C a n n a b i s p i r a n o l : A n e w n o n - c a n n a b i n o i d p h e n o l f r o m C a n n a b i s s a t i v a L. ~ E. G. Boeren, M. A. Elsohly, C. E. T u r n e r 2 a n d C. A. S a l e m i n k 3
Research Institute o/ Pharmaceutical Sciences, School o/ Pharmacy, University of Mississippi, University (Mississippi 38677, USA), 6 December 1976 Summary. A n e t h a n o l e x t r a c t of C a n n a b i s s a t i v a L. a f f o r d e d u p o n p a r t i t i o n i n g a n d r e p e a t e d c h r o m a t o g r a p h y a n e w n o n - c a n n a b i n o i d p h e n o l [ 7 ' - h y d r o x y - 5 ' - m e t h o x y - s p i r o - (cyclohexane-1, l'-indan)-4/3-olJ(IIIa), n a m e d fl-cannabispiranol. C a n n a b i s p i r a n s t r u c t u r e (I) as d e t e r m i n e d b y X - r a y c r y s t a l l o g r a p h y 4 r e p r e s e n t e d a n e w class of c o m p o u n d s d i s c o v e r e d in c a n n a b i s . I n a p r e v i o u s c o m m u n i c a t i o n 5 we h a v e r e p o r t e d t h e isolation of c a n n a b i s p i r a n (I) a n d d e h y d r o c a n n a b i s p i r a n (II) f r o m an e t h a n o l i c e x t r a c t of a S o u t h African v a r i a n t of c a n n a b i s g r o w n in Mississippi. F u r t h e r e x a m i n a t i o n of t h e a b o v e e x t r a c t r e s u l t e d in t h e isolation of a n e w r e l a t e d c o m p o u n d 7 ' - h y d r o x y - 5 ' m e t h o x y - s p i r o - ( c y c l o h e x a n e - l , l ' - i n d a n ) - 4 f l - o l w h i c h we n a m e d f l - c a n n a b i s p i r a n o l ( I I I a ) . The s t r u c t u r e of I I I a is t h e s u b j e c t of t h i s r e p o r t . fl-cannabispiranol ( I I I a ) , m . p . 179-183~ R R T 0.326; C15Ha003 (M+. 248) was o p t i c a l l y inactive. The U V spect r u m s h o w e d p e a k s a t ,qMeOH 207 (log e 3.85) a n d 221 n m --max (3.82). The I R s p e c t r u m (KBr) s h o w e d b a n d s a t 3440
(OH), 3190 (OH), 2910 (CH), 2845 (OCH), 1625 and 1595 (C=CAr), b u t no c a r b o n y l a b s o r p t i o n . The 1 H N M R s h o w e d a singlet a t 63.60 (3H) (OCH3) , 2 a r o m a t i c p r o t o n s a t 66.10 (s) a n d 2 p r o t o n s a t 63.05 a n d 67.95 w h i c h were e x c h a n g e a b l e w i t h D20. Most i m p o r t a n t was a p e n t e t a t 63.98 (1H J : 3 H z ) assigned t o - C H O H - . T r e a t m e n t of I I I a w i t h acetic a n h y d r i d e in p y r i d i n e yielded a d i a c e t a t e ( I I I b ) , m . p . 127-128~ R R T 0.58; w h i c h s h o w e d I R b a n d s a t 1763 a n d 1731 c m -1 (arom a t i c a n d a l i p h a t i c a c e t a t e s respectively) 7. The m a s s s p e c t r u m s h o w e d p r o m i n e n t ions a t m / e 332 (16%)
(M+.) (for C19H2405); 290 (85%) ( M - H 2 C = C = O ) + . ; 272 (28%) (M-CH3COOH)+.; 230 (85%) ( M - H 2 C = C = O H3CCOOH)+.; 189 (61%); 187 (16~ a n d 176 (100%). I n a d d i t i o n t o t h e a c e t a t e m e t h y l s a t 62.10 (3H, s), 2.31 (3H, s), t h e 1 H N M R s h o w e d a p e n t e t a t 65.05 (1H) assigned to - C H O A c - . T h e s e d a t a s u g g e s t e d t h a t I I I a m i g h t be a d i h y d r o d e r i v a t i v e of c a n n a b i s p i r a n (I). This was p r o v e n t o be t h e case b y r e d u c t i o n of c a n n a b i s p i r a n w i t h N a B H 4 in M e O H w h i c h r e s u l t e d in t h e f o r m a t i o n of 2 isomeric p r o d u c t s in a 1:4 ratio (by GLC analysis) w i t h R R T 0.32 a n d 0.36. TLC of t h e r e a c t i o n p r o d u c t s h o w e d 2 s p o t s (Rf 0.43 a n d 0.55, CHC13-EtOAc, 1:1), t h e less polar of w h i c h was t h e m a j o r c o m p o n e n t . S e p a r a t i o n was a c h i e v e d b y c h r o m a t o g r a p h y on silica gel G
OH ~
R1
H3CO~ I
R1 +
R~ =
=
0
II IIIa
R1 + R2 = = o, Act, fltocarbonylgroup R1 =
OH,
IIIb
R1 =
OAc,
IVa
R1 =
Hb, R 2 =
OH
IVb
R1 =
Hb, R 2 =
OAe
R2 = R2 =
Ha Ha
R2
c o l u m n using t h e p r e v i o u s TLC s o l v e n t s y s t e m . T h e m o s t p o l a r isomer ( R R T 0.32, Rf 0.43) was f o u n d to be i d e n t i c a l w i t h t h e n a t u r a l p r o d u c t I I I a (TLC, m . p . , I R a n d MS). The i s o m e r I V a ( R R T 0.36) h a d m . p . 176~ and similar s p e c t r a l d a t a to I I I a . The 1 H N M R h o w e v e r , s h o w e d t h a t Ha was o v e r l a p p i n g w i t h t h e m e t h o x y signal. T h u s I r a was a c e t y l a t e d (acetic a n h y d r i d e in pyridine) t o give a d i a c e t a t e I V b , m . p . 85-86~ R R T 0.48 a n d v m a x (KBr) 1770 a n d 1735 c m -1. The 1 H N M R (CDC13) of I V b s h o w e d 2 a c e t a t e m e t h y l s a t 62.00 (3H, s) a n d 62.25 (3H, s) a n d m o s t i m p o r t a n t was a b r o a d m u l t i p l e t b e t w e e n 64.33 a n d 4.91 (1H) assigned t o t h e p r o t o n u n d e r t h e a c e t o x y g r o u p Hb. B a s e d on t h e ~ H N M R of I I I a a n d I r a and their acetates I I I b and I V b the hydroxyl group on t h e c y c l o h e x a n e ring of I I I a was assigned t h e axial p o s i t i o n a n d t h e h y d r o g e n Ha t h e e q u a t o r i a l position. T h e e q u a t o r i a l Ha couples w i t h t h e n e i g h b o r i n g axial a n d e q u a t o r i a l h y d r o g e n s w i t h t h e s a m e coupling c o n s t a n t r e s u l t i n g in a p e n t e t J = 3Hz. O n t h e o t h e r h a n d I V a w a s assigned an e q u a t o r i a l O H a n d axial H. T h e 1 H N M R of I V b s h o w e d p r o t o n Hb as a b r o a d m u l t i p l e t as a r e s u l t of coupling w i t h 2 axial p r o t o n s and 2 e q u a torial p r o t o n s on b o t h sides with d i f f e r e n t coupling constants. U p o n b u i l d i n g a D r e i d i n g m o d e l of I I I a a n d I r a it was f o u n d t h a t t h e molecules h a d a p l a n e of s y m m e t r y w h i c h bisects t h e i n d a n nucleus a n d w h i c h e x p l a i n s t h e optical i n a c t i v i t y of b o t h c o m p o u n d s . This is t h e first r e p o r t of f l - c a n n a b i s p i r a n o l in n a t u r e .
1 Acknowledgments. Supported by contract HSM-42-70-109 and grant DA-00928-01 from the National Institute on Drug Abuse as well as the Research Institute of Pharmaceutical Sciences. The authors are grateful to Mrs Glenda Lewis for running the GC analyses and to Dr Stephen Billets for running the Mass Spectra. Cannabis Herbarium specimens are stored in the Herbariunl, Department of Pharmacognosy, School of Pharmacy, University of Mississippi, USA. 2 To whom correspondence should be addressed. 3 Laboratory of Organic Chemistry, State University of Utrecht, the Netherlands. 4 T. Ottersen, A. Aasen, F. S. E1-Feraly and C. E. Turner, Chem. Comm. 1976, 580. 5 F. S. E1-Feraly, M. A. Elsohly, E. G. Boeren, C. E. Turner, T. Ottersen and A. Aasen, Tetrahedron, submitted for publication. 6 All gas chromatographic analyses were performed on a 2~o OV-17 column at 210 ~ using androst-4-ene-3,17-dione as the internal standard as described by C. E. Turner and K. Hadley, J. pharm. Sci. 62, 251 (1973). 7 K. Nakanishi, in: Infrared Absorption Spectl'oseopy-Pratical, p. 42. Holden-Day Inc., San Francisco 1962.
