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Ingenane and lathyrane diterpenes from the latex of Euphorbia canariensis
564
J. A. MARCO et al.
10
RI 1 2 3 4 5 6 7 8 8a
,. ,,,,
Ang Ang Ang Ang Ang Ang Ang H AC
R,
R4
AC H AC AC H AC AC Ang Ang
H OBz OBz OAc H :: OBz OBz
?&,,* 5 R's
-
==
Acd R
OR R’
9
Bz
H
9a 9b 10
Bz AC
AC AC
iBu
H
‘I
11
3-angelate 20-acetate, as deduced from chemical shift considerations. Esters of 5-deoxyingenol have previously been described but are comparatively rare [6]. Compound 8 17-hydroxyingenol 17-benzoate 20angelate, was not present in the latex of E. cunariensis, but was slowly found in some fractions containing ingenol diester (2), 17-hydroxyingenol 3-angelate 17benzoate. This shows once more the ease with which intramolecular acyl migrations occur in ingenol esters, not only during partial hydrolyses [8, 1 I] but also during chromatographic manipulations. The ‘H NMR data of 8 and its acetate 8a are described in the Experimental; their 13CNMR data are given in Table 2. High-resolution NMR data were not always provided in earlier reports of compounds l-5. We thus
report the ‘H NMR data for all ingenane derivatives isolated in the present work, including the known ones, in Table 1, as well as the corresponding ‘jC NMR data in Table 2. The configurations of all stereogenic centres have been reconfirmed with the aid of NOE measurements, whereas the carbon signals have been unequivocally assigned using HMQC/HMBC experiments. The latter further provided unequivocal evidence for the locations of the ester residues through observation of long-range H-C-GCOR correlations [13, 141. The CIMS data of compound 9 (highest mass peak at m/z 555) indicate the molecular formula C31H3809. The NMR data (Tables 3 and 4) show the presence of a benzoate and two acetate groups. The hydrogen and carbon connectivities deduced from HMQC and HMBC experiments aided in establishing the lathyrane framework and allowed the conclusion that 9 is structurally close to a triester of ingol bearing two acetoxy groups at C-7 and C-12 and a benzoyloxy residue at C-8. In fact, acetylation of 9 gave 9a, which has NMR data similar to those of ingol 3,7,12-&iacetate 8-benzoate [15]. Several NMR features, however, that 9 is not an ingol derivative. A most notable point is the value of J2,3 (5.5 Hz), which is quite different from that observed in true ingol esters (ca 8.5 Hz). Further relevant differences are observed in the chemical shifts of the H-l protons, which appear in the spectra of ingol derivatives at ca 1.7CL1.65 and 2.8g2.70 ppm [9, 15-201, a marked difference from those measured in 9 (Table 3). Finally, alkaline hydrolysis of 9 and subsequent acetylation yielded a tetraacetate 9b, the spectral data of which are different from those of ingol tetraacetate [9]. Thus, compound 9 is a stereoisomer of ingol 7,12-diacetate 8-benzoate. The similarity of chemical shift and coupling constant values in the fragment C-5 to C-13 of 9 with those published for ingol esters [9, 15-201 led us to conclude that configurational and conformational aspects of the 1 l-membered ring are essentially the same in all these compounds. The stereochemical differences were thus centred on the five-membered ring, most likely at C-2 and/or C-3. Unfortunately, the NOE data were not conclusive in the present case. For instance, a NOE was visible between the methyl group at C-2 (H-16) and both H-3 and 3-OH. Further NOES were observed between H-2 and H-3, between H-3 and H-5, and between 3-OH and H-5. In view of this situation, we resorted to molecular modeling using ‘MacroModel’ [21]. Since the chemical shift values of the carbon atoms from C-6 to C-14 are essentially the same as in ingol esters [9, 18-20, 221, we maintained the p configuration for the epoxide ring (inversion to an a-epoxide would cause appreciable changes in these values, most particularly in the signals from carbons near to the five-membered ring). We then considered all four possible stereoisomers of ingol tetraacetate at C-2/C-3 (A-D, see Scheme 1) and used the aforementioned program to optimize their geometries. This was performed through a Batchmin
Table 1. ‘H NMR data of ingenane H
1
2*
1 3 4-OH 5 I 8 11 12a
6.02 br d (1.5) 5.55 S 3.45 S 3.89 br d (7)t 6.10 br d (4) 4.09 br dd ( 12; 4) 2.49 m 1.76 ddd (16; 6.5; 5) 2.22 ddd (16; 8.5; 2.7) 0.69 ddd (8.5; 8.5; 6.5) 0.95 dd (12; 8.5) 1.03 S 1.06s
6.02 5.57 3.60 4.03 6.00 4.33 2.55 1.90
128 13 14 16 17 18 19 20 OAc OAng
0.96 1.78 4.74 4.47 2.04 6.15 1.99 1.90
d (7) d(1.5) br d (12.5) br d (12.5) s (3H) qq (7; 1.5) dq (7; 1.5) dq (1.5; 1.5)
br d (1.5) S s br s br d (4) br dd (12; 4) m WlT
derivatives
3*
4
5
6
6.02 brd(1.5) 5.57 s
6.03 br d (1.5) 5.52 s 3.50 S 4.06 br s 6.06 br d (4) 4,14brdd(12;4) 2.52 m 1.75 ddd (15.5; 7; 6.5) 2.25 ddd (15.5; 8.5; 3) 0.69 ddd (8.5; 8.5; 6.5) 0.95 dd (12; 8.5) 1.04s 1.08 s
6.08 5.04 3.30 5.42 6.23 4.24
2.41 ddd (15.5; 9; 2.8) 1.00 mf[
2.39 ddd (15.5; 9; 2.8) 1.OOrnq
6.02 brd(1.5) 5.55 s 3.45 s 3.88 br d (5)f 6.10brd(4) 4.19 br dd(12; 4) 2.49 m 1.85 ddd (16; 6.5; 6.5) 2.30 ddd (16; 8.5; 3) 0.95 rn7
1.22 ml
1.22 dd (12; 8.5) 1.21 S 4.52 d(11.8) 4.36d(11.8) 0.98 d (7) 1.78 d(1.5) 4.66 br d (12.5) 4.38 br d(12.5) 1.98 s (3H) 6.13 qq (7; 1.5) 1.98 dq(7; 1.5) 1.88 dq (1.5; 1.5)
1.15 dd (12; 8.5) 1.12 S 4.26 d(11.8) 4.12 d(11.8) 0.97 d (7) 1.79d(1.5) 4.74 br d (12.5) 4.47 br d(12.5) 2.05 s (6H) 6.17 qq(7; 1.5) 2.00 dq (7; 1.5) 1.91 dq(1.5; 1.5)
1.22s 4.57 d (11.8) 4.36d(11.8) 0.98 d (7) 1.78 d(l.5) 4.06 br s (2W 6.14qq(7; 1.5) 2.00 dq (7; 1.5) 1.90 dq (1.5; 1.5)
6 in ppm and J (parentheses) in Hz (400 MHz, CDCl,, 22”). * OBz: 8.03 dd (2H; 8; 1.5), 7.56 tf (IH; 8; 1.5), 7.45 t (2H; 8). t The 5-OH appears at 6 3.60 d (7). 1 The 5-OH appears at 6 3.50 br d (5). §(5aH); 5/IfH appears at 6 2.36 br d (18.5). 7 Overlapped signal.
l-7
3.86 6.08 4.29 2.52 1.90
br s br d (4) br dd (12; 4) m my
0.96 d (7) 1.79 brs 4.14 br s (2H) 6.16 qq (7; 1.5) 2.01 dq (7; 1.5) 1.92 dq(1.5; 1.5)
7 br br br br br br
d (1) s s s d (4) dd (12; 4)
2.54 m 1.75 ddd (16; 6.5; 6) 2.28 ml
6.00 br s 5.01 S 2.70 br s 2.52 d (18.5)s 6.05 br f (2) 4.12brd(11.5) 2.40 m 1.79 ddd (15.5; 7; 6) 2.17 ddd (15.5; 8; 3)
0.70 ddd (9; 8.5; 6.5) 0.96 dd (12; 8.5) 1.05 S 1.07 s
0.70 ddd (8; 8; 7) 0.95 my
0.98 d (7)
0.96 d (7)
1.76 d(1) 4.60 br d (12.5) 4.19brd(12.5) 2.24 s, 2.00 s (2 x 3H) 6.10 qq (7; 1.5) 1.96 dq (7; 1.5) 1.89 dq (1.5; 1.5)
1.78 brs 4.36 br s
F B 2 z g a c B v: @ ,3 ac. f % 3
1.04s 1.10s
(2H) 2.05 6.16 2.00 1.91
s (3H) qq (7; 1.5) dq (7; 1.5) dq (1.5; 1.5)
S h % z 5 a a” g ,T. S 2.
Table 2. “C NMR data of ingenane
derivatives
lga
C
1
2
3
4
5
6
7
8
8a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 OAc
132.2 136.0* 82.7 84.9 74.8 135.9* 129.5 43.6 206.3 72.1 38.5 31.1 23.3 23.1 24.0 28.5 15.5t 17.3 15.6t 66.8 171.1 21.1 168.4 140.0, 127.1 20.8, 16.0
131.6 136.2 82.2 84.9 76.6 139.7 127.2 43.2 205.9 72.0 38.4 30.9 24.3 23.5 27.7 24.6 66.2 16.9 15.6 67.2
131.6 136.2 82.3 84.9 74.7 136.4 128.2 43.2 205.5 72.0 38.5 30.9 24.3 23.5 27.7 24.5 66.1 16.9 15.6 66.5 170.9 21.0 168.2 140.0, 20.7, 166.7 133.0, 129.5,
131.7 136.4* 82.5 84.9 74.9 136.3* 128.7 43.3 205.5 72.1 38.5 30.9 24.3 23.5 27.5 24.4 65.6 17.0 15.6 66.7 171.4, 171.0 21.0(x2) 168.3 140.2, 127.1, 20.8, 16.0
132.1 135.7 82.5 84.7 77.1 139.0 128.6 43.5 206.6 72.0 38.3 31.1 23.3 23.0 24.0 28.5 15.5 17.3 15.5 67.5
132.0 135.6 81.8 85.8 74.9 133.3 131.7 43.6 205.6 72.0 38.6 31.1 23.1 22.9 24.3 28.4 15.4* 17.0 15.5* 65.9 170.8, 170.7 20.9, 20.8 169.1 139.1, 127.4 20.7, 15.8
132.3 136.1 85.7 80.5 43.7 132.4 128.8 44.2 208.4 75.0 37.0 31.5 23.7 23.2 23.6 28.6 15.5* 18.2 15.6* 68.5 170.8 21.0 168.6 139.9, 127.1 20.7, 15.9
128.9 139.4 80.1 84.4 73.7 137.4 126.2 43.6 206.0 72.5 39.6 30.7 24.2 23.5 27.7 24.4 66.2 16.9 15.3 65.8
131.8 135.7 82.0 85.7 74.6 133.8 130.4 43.2 204.3 71.8 38.6 30.9 24.1 23.5 28.0 24.4 66.2 16.6 15.3 64.9 172.3, 21.1, 167.2 138.4, 20.5, 166.7 133.0, 129.5,
OAng
OBz
168.4 139.8, 20.8, 166.7 133.0, 129.6,
127.2 15.9 130.3 128.4
127.0 15.9 130.2 128.3
168.5 140.0, 127.2 20.8, 16.0
-
6 in ppm (100 MHz, CDCl,, 22”). Signals have been assigned by means of 2D-NMR experiments. *,t Signals with the same superscript may be interchangeable within the same column.
167.9 138.4, 20.5, 166.9 133.0, 129.5,
127.6 15.7 130.1 128.4
170.6 20.7 127.5 15.7 130.2 128.4
Table 3. ‘H NMR data of lathyrane H la 1B 2 3 5 7 8 9 11 12 13 16 17 18 19 20 OAc
OBz
9*
9a
9b
1.92 rn§ 2.20 ml 1.92 rn§ 3.98 f (5) 6.02 br s 5.24 br s 4.80 dd(10.5; 1.5) 1.40 dd(10.5; 9) 1.2Odd(ll; 9) 4.90 dd(l1; 4) 2.97 dq (4; 7) 0.98 d (6.5) 2.12 br s 1.11 S 0.80s 1.03 d (7) 2.05 s (3H) 2.04 s (3H)
2.01 dd(13.5; 7) 2.26 dd(13.5; 10.5) 2.10 mQ 5.29 d (5.5) 5.68 br s 5.30 br s 4.82 dd(10.5; 1.5) 1.37 dd(10.5; 9) 1.24dd(ll;9) 4.92 dd(ll; 4) 2.99 dq (4; 7) 0.93 d (7) 2.14 br s 1.16s 0.83 s 1.07 d (7) 2.11 s (3H) 2.09 s (3H) 2.05 s (3H)
2.00 2.25 2.10 5.28 5.63 5.19 4.56 1.20
dd(13.5; dd(13.5; mQ d (5.5) br s brs dd(10.5; r (10.5)
(2H) 4.86 2.91 0.92 2.07 1.11 0.84 1.05 2.10 2.09 2.08 2.00
dd(10.5; 4) dq (4; 7) d (7) br s s s d (7) s (3H) s (3H) s (3H) s (3H)
7.96 dd (2H; 8; 1.5) 7.52 ff (1H; 8; 1.5) 7.40 t (2H; 8)
7.98 dd (2H; 8; 1.5) 7.56 tt (1H; 8; 1.5) 7.43 t (2H; 8)
6 in ppm and J (parentheses) in Hz (400 MHz, CDCI,, *3-OH: 2.50 br d (5). t 3-OH: 1.65 d (5). $ OiBu: 2.48 qq (7; 7), 1.13d (3H; 7), 1.1 I d (3H; 7). § Overlapped signal. YjNon-first-order signal.
22”).
derivatives
9-11 lW,S
7) 10.5)
1.5)
_
1.95 rn§ 2.25 ml I .95 m$ 4.02 t (5) 6.00 br s 5.20 br s 4.60 dd(10.5; 1.5) 1.28 dd(10.5; 9) l.l4dd(ll, 9) 4.86 dd(l1; 4) 2.95 dq (4; 7) 1.02 d(6.S) 2.09 br s 1.09 s 0.84 s l.O4d(7) 2.12 s (3H) 2.09 s (3H)
11 2.10 mp 2.10 rn§ 1.90m 5.05 d (8.8) 5.65 br s 5.08 d(l.5) 4.80 dd(l1; 1.5) 1.46 dd(l1; 9) 1.15 dd(l1; 9) 4.90 dd (11; 4) 2.98 dq (4; 7) 1.03 d(7) 2.13 br s 1.15s
0.82 s 1.OS d (7) 2.13 s (3H) 2.08 s (3H) 2.04 s (3H) 8.00 dd(2H; 1.5) 7.57 tt (IH; 8; 1.5) 7.44 t (2H; 8)
6 % $ z !z a i; F ‘< ti a f 3 3 3 h d z ? Q “a as 2. 3 2.
568
J. A.
MARCO
et
al.
Table 4. 13C NMR data of lathyrane
derivatives
9-11
C
9
9s
9b
10*
11
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 OAc
32.1 33.0 76.4 72.5 116.8 137.4 77.3 72.1 24.7 19.3 30.7 70.7 43.2 207.8 73.1 12.0 17.5 29.1 16.1 13.3 170.5, 21 .o, 165.8 133.2, 129.5,
32.7 32.5 77.2 70.7 115.2 139.1 76.8 72.0 24.8 19.4 30.8 70.5 43.4 207.4 73.0 12.3 17.6 29.1 16.2 13.2 170.3, 21.0, 165.8 133.2, 129.5,
32.7 32.5 77.1 70.7 115.4 138.8 76.5 71.4 24.5 19.2 30.5 70.5 43.3 207.3 73.1 12.3 17.6 29.0 16.1 13.2 170.4, 170.3, 169.6, 169.2 21.0, 20.9 ( x 2), 20.6
32.1 32.9 76.6 72.4 116.6 137.6 76.7 71.4 24.6 19.2 30.6 70.7 43.1 207.6 73.1 12.0 17.6 29.1 16.3 13.3 170.4, 169.8 21.1,21.0
31.1 31.0 80.4 69.8 117.0 139.7 77.3 71.6 25.2 19.6 30.8 70.7 42.9 207.3 71.4 16.1 17.3 29.2 16.1 13.5 170.8; 21.0 165.7 133.2, 129.6,
OBz
169.9 20.9 129.7 128.4
169.5, 169.0 20.8, 20.6 129.7 128.4
6 in ppm (100 MHz, CDCl,, 22”). Signals have been assigned *OiBu: 176.3, 33.9, 18.8, 18.7.
A (8-9 Hz)
B (8-9 Hz) 0
0
IllI.
& 4 2
Ri c Scheme
R6
(5.5 Hz)
1. Calculated
& values stereoisomers
D (1.5 Hz) (in parentheses) A-D.
for ingol
search and energy minimization [21], which provided the lowest energy conformers for each possible diasteroisomer. For two of them, the ingoltype derivative A and its 2-@isomer B, J2,3 values in the range 8-9 Hz were calculated. For the 2,3diepiisomer C, the predicted J2,3 was 5.5 Hz, while for the 3-@isomer D, a J2,3 value of ca 1.5 Hz was found. Thus, we concluded that a 2,3-diepiingol derivative is conformational
by means of ZD-NMR
170.3, 169.9 ( x 2), 20.7 129.7 128.5
experiments.
present in the case of 9, and that is therefore 2,3diepiingol 7,lZdiacetate 8-benzoate. The interatomic distances and the NOES predicted for this structure were in good agreement with the actual observations. According to NMR evidence, compound 10 is very close to 9. Chemical shifts and coupling constants are almost identical in both compounds (Tables 3 and 4), the only difference being the presence of an isobutyrate group in 10 instead of the benzoyl group found in 9. Compound 10 is, therefore, 2,3-diepiingol 7.12-diacetate 8-isobutyrate. Compound 11 is closely related to 9a, as evidenced from NMR data. All spectral data, including heteronuclear 2D NMR measurements, point to an ingoltype tetraester bearing acetoxy groups at C-3, C-7 and C-12, and a benzoyloxy group at C-8. One main difference with 9a is the coupling constant J2,3 = 8.8 Hz. However, 11 is not an ingol ester, in view of the chemical shifts of the H-l protons (Table 3) and of the five-membered ring carbons (Table 4) [9, 18-20, 221. On the basis of the aforementioned molecular mechanics calculations [21] and of the value of J2.3, we concluded that 11is a stereoisomer of ingol displaying the B-type configuration in the five-membered ring. Compound 11 is thus 2-epiingol 3,7,12-triacetate 8benzoate. This product represents the second report in the literature of a 2-epiingol derivative. The first members of this compound class have been described very
OI’Z ‘(WO-S ‘S ‘HE) OZ’Z ‘(dZI-H ‘ZH L’Z ‘6 ‘91 = f ‘ppp ‘HI) OP’Z ‘(II-H ‘u ‘HI) PS’Z ‘(HO-P ‘S 44 ‘HI) SZ’E ‘?OZ-H ‘ZH S’ZI = f ‘P 19 ‘HI) SZ’P ‘(qLI-H ‘ZH 8’11 = f ‘P ‘HI) 8f’P ‘(“OZ-H ‘“LI-H ‘8-H ‘~4 A9 ‘HE) 8P’t ‘(f-H ‘S 19 ‘HI) S6’P ‘(S-H ‘S 19 ‘HI) OP’S ‘(D!u -yaIO aleIa%lC?‘ZH 5.1 ‘L =f ‘66 ‘HI) ZO’9 ‘(I-H ‘ZH 5‘1 =f‘P”9’HI)90’9‘(L-H‘ZHS’P=f“P~9‘HI)PZ’9 ‘(~~~WLlOJtWl2Ui‘ZH 8 = [ ‘1 ‘HZ) fP’L ‘(3!~WIO.Wv.ivd ‘ZH S’I ‘S’L = f ‘11‘HI) PS’L ‘(~~Jl?LUO.It?-0yW‘ZH S’I ‘S’L = f ‘pp ‘HZ) 20’8 9 (ZHYI OOP “13CI3) ‘dKN H, :k?g ahe8 (dwal ulo0.1 ‘au!p!lkd/@V) uo!le[6~a~V ‘Z aIqeL ‘XWN 3<, :(81-H ‘ZH L = f ‘p ‘HE) 56’0 ‘(EI-H ‘W paddeIlaAo ‘HI) S6’0 ‘(PI-H ‘ZUpaddeIJaAo ‘HI) ZZ’I ‘(91-H ‘S ‘HE) ZZ’I ‘(al4 aWa%ue ‘61-H ‘.s49 ‘H9) 08’1 ‘(ZIZI-H ‘LUpaddepaAo ‘HI) 28.1 ‘(aK aleIa%IC? ‘ZHS’1‘L=f‘~~‘Hf)68’I‘(dZI-H‘1I-H‘~~9‘HZ) OP’Z ‘(HO-S ‘ZH 01 = I ‘P 19 ‘HI) SP’E ‘(S-H ‘ZH 01 = f ‘P 19 ‘HI) 99.f ‘(Ho-f ‘s 19 ‘HI) 06.f ‘(8-H ‘ZH S’P ‘ZI = f ‘PP “9 ‘HI) OE’P ‘(f-H ‘S 19 ‘HI) ZE’P ‘(HO -ti ‘S 49 ‘HI) OP‘P ‘(qLI-H ‘ZH 8’11 = f ‘P ‘HI) SP.P ‘(“LI-H ‘ZH 8’11 = f ‘P ‘HI) SS’ti ‘(‘OZ-H ‘ZH f 1 = f P 19 ‘HI) 9S’P ‘(“OZ-H ‘ZH El = f P ‘HI) 893 ‘(1-H S’I = f ‘p A9 ‘HI) 88’S ‘(3!UyalOall?Ia%Ur! ‘ZH 5.1 ‘ZH
‘L = f ‘M ‘HI) ZO’9 ‘(L-H ‘ZH ST = f ‘P 49 ‘HI) f0’9 ‘(3!~l?UIOD?-Vjc9U4 ‘ZH
5.1
‘S’L
=
f
‘ZH ‘11
8 =
f
‘HI)
‘j ‘HZ) PS’L
EP’L
‘(3!l~uIO~l?-vAVd
‘(3!)EuIO.lW~jAO
‘ZH
S’I ‘S’L = f ‘PP ‘HZ) 20’8 9 (ZHIIV OOP ‘E13a3) XKN H, %IL ‘S96‘9PIl ‘8921 ‘LLEI ‘ZSPI ‘OOLI ‘SILI‘(HO ‘J9) OfPf :,-m3 ::* XI f(6’Z 3 %H3) .S’La[ml ‘I.‘0 ‘(8) alv@lv-OZ awozuaq-LI ]OUd%4~dXOAp~H-L 1 ‘2 PUC I sa1qKL ‘WYN t06SZ’LSP = J4’ ‘90’EHLi3 “?I PVT.) ‘(6f) 19‘(SZ) 101 ‘(PC) + [03-HOSUV-H03V-OSH-H + K] 692 ‘(t+) + [HOBUV-H03VQzH-H + K] 6LZ ‘(001) + [HOSUV-HOY-H + W] L6Z ‘(P) +[HO~uV-O’H -H + IX] 6ff ‘(S I) +[HOzuV-H + W] LSE ‘(9) +[HOT -O’H-H+ K] 6Lf ‘(9) +[HOW-H+ W] L6f ‘(Z) + tOiH-H + k’i] 6fP ‘(9) +[H + K] ZO9Z‘LSP :(‘lu! ‘IaJ) z/m (‘H3) SE’K-tf88 ‘9f6 ‘PEOI ‘SSI I ‘SEZI ‘9Lf I ‘ESPI ‘(0=3auolaXPu~Jalsa)P691 ‘8691 ‘LILI ‘9fLI ‘(HO ‘A9) OSPE I,-‘=’ :;A XII t(S.0 3 %H3) &‘I + a[;~] ‘ITO ‘(L) aztwwv-OZ ajv@4v-f ~ouaGu~iCxoaa-S ‘130 (dtuaj u1o0.1 1(q pau!elqo 13npold aq$
‘au!p!l,Jd/@3V)
uog~Il(la~
Yl!M 3’I.L Pue Xk’IN dq I’WuaPI ‘Z PUE I SaIqel ‘WYN 2479Z’SIS = Jl’ ‘806EH6Z3 “OJ PT3 ‘(85) 19 ‘(OS) IO I ‘(OZ) +[03-HOZUV-H03VZ-H + JX] L9Z ‘(06) + [HOBUV-HOWZ-H + W] 562 ‘(00 I ) + [HOZUV-HOY-H + I4] SSf ‘(9) + tH08uV-H + K] SIP‘(S) +[HOzV-H+R] SSP ‘(9) +[H+kT] 099Z’SIS :(.lu! ‘Ial) z/U’ (*H3) SKI3 tZ68 ‘906 ‘PEOI ‘691 I ‘ZPZI ‘ELEI ‘Z9PI ‘SS91 ‘(c)---3 auolay Pue Jalsa) 5691 ‘6OLI ‘9fLI ‘OPLI ‘(HO ‘AS)OZPE :,-u3 :;A XI f(f 3 ?3H3) ,&I + a[7J]‘I!0 ‘(9) ~~V~~WV~~Z‘S-~~V~~UV-~-~OU~~U~ J~JJE z 8u!u!aluo~ ~“3 autos u! aq$u! IuasaJd kllT?!l!U! $~II f) s pue (%u L) p ‘(%w
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$0~ SBM 8 punoduIo3
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30 laplo 8u!MolIo3 aql u! uurnIo3 IaS eDy!s aql ~uo~3 pa]nIa aJaM -lallvI aqL ‘lxal ayl u! pauoguauI spunod -u103 aql30 pue sauad.tal!n 30 slunoruv ~~uo!l!pp~ 30 uo!]eIos! aqJ paMoIIe ?.ry~ ‘3TdH lo/pue 37~ ,dald kq ‘kEssaDau alaqm ‘pay!md _taqlmn3a.taM s_13awpatu -law! ayL .(ozig + I:OI #la-auexay ql!~ uognla) Ia% e~I!s uo 33 01 pal3a[qns SBM ‘13 aIpp!w aql 'MoIaq paq!l%ap se suogwedas ~!ydeBoleur -oJy:, laqlJn3 01 paparqns stz~ (8 11 v3) uog -3~13 aipp!w aqL .AIaAgDadsaJ ‘(Ioqloydna PUG loydna @~eur) sauadlalpl UOUI~IO~pue spunodmo3 pauyap -II! ‘IeIod pau!eluoD AIuo LayI SE pap.w3s!p aJaM sq HOaM pue .lall?M ayl ‘HOan Q!M Qeuy pue (f:L) O’H-H@‘m ql!M Uaql ‘JaleM ql!M @sJy (WJ e lapun palnIa pue [a% KXJS z-s' 1) aJnssaJd IV @Is 30 adlCl auuzs aql ypm paIIy uuInIo3 3gde.Bolewo~q~ I! 30 doI aql uo paDe[d SBM pau!elqo Ie!laleuI kap -Mod aqJ_ ‘on3viI UJ paleu!uI!Ia kp$Ol uayl SBM luaA[os ayL jOI] (wqxa 30 %/Ias w!I!s 30 8 f) pappv SI?M Ia e~I!s aseyd-aslaAa1 ‘HoaM 30 lunome unn.u!u!ru ayl u! po syl Bu!~~oss!p Iaj3V ‘(2 9I a~) Ie!Jaleru i(po ‘qS!l!qM B ah&i On3vn u! luaA[os aql30 uoge.IodeAcJ ~o!~e~lIy icq pawuywga SBM q3!y~ '[g]sauadJa$g uoun.uo~ 30 alel!dpald a)!qM ‘snou$nIoA 01 as!1 aAe2 dwal WOOJ 01 BwIoo3-al pun (I I) Hoam $0~ u! xalel agl30 uo~~n[oss~a ~kydvA6ojvuroryJ puv uo~j.3v~jx~ ‘EJ3!JJUauaJ‘.n?unnf) (3 06 113) S,NG’~AVUV3
ap s!vdIEW u! pa$Da[IoD SCM 30 Xalt21 alJJ_ ‘~“&0jVtU lUV\d
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May ‘slx!UJ OZH-HOaw ql!M UO!ln[a ‘(WUJ 8 X OSZ) 8-dll q”osoJYB!‘I TIdH t(61 LLO W’) Wak’I Ia e~!I!s paz!ue[!s Ia ?X!I!Saseyd-as.IaAaJ t(u~ti OOZI)S az!s aIDp.wd) gV a!uxayDpns Ia% EXI!S :33 alnssaJd ~XUJOU f,ZZ 1~ $I~HD :suogelo~ Iwgdo tlalaruowads SSl2IU
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fa%a.Ia
-3aJ sv SI”u%!s JuaAIos ‘(&,) ZHYI 001 Put! (H,) ZHI4 009 1~ pvayaqoJd as.IaAu! ue ql!~ t13a3 :?HJN
-Ied asayl u! aIqes!Apv aq ~y8!u1 uo!s!Aal pnwu~s v ‘ZH f’[ 10 s’s SF E’Zf alaym spunodwo:, ayl ~03 iCIay!Ilou s! s!yl ‘.IaAaMOH ‘.Iay$o yxa 01 nI!ur!s al!nb 0sIe ale dI-H pw ;0I-H 30 sanIeA 13!ys p23!way3 ayl asu!s ‘saAgeA!Jap 10%~~dl!I!qeqold IIe u! an? ZH S’g VJ s! E‘Zf alaqM spunoduro3 paysgqnd Qsno!Aald \Ie ‘[fZ] uopda3xa pauoguauralo3t! aql ql!M ‘zH S’OTS.8 30 aWelt? U!I@M sailas aql q%no.rq] ~ue~suo~ iCIIc3!13wd u!erual ppoqs ~uelsuo~ %.nIdnoa pauoguaura.to31? ayl ‘sanp!sal Jalsa ayl 30 amleu ayl u! Quo lag!p spunodwo:, asaql30 II” ‘aId!c)u!.‘d u! ‘aDu!S .[pZ ‘f I] ZH f’1 Pue [VI] ZH S’S ‘[OZ-SI ‘61 ZH S’OT S’8 :SaA!lzA!JaP IO&I! pawnsse sno!.reA 103 paqsgqnd dIsno!AaJd alaM sanIeA E‘Zf 8u~moIlo3 aql ‘aDuelsu! loa %!uoguaur yl.10~ s%u!puy papla@ elep pays!Iqnd ayl30 uop~u! -tuexa In3a.w3 V ‘amwalg aql u! pal1oda.x Qsno!A -aId alaM IO%U!30 slaur!da ou ‘s!y~ ~0.13 ap!sV .[fZ] ~1 30 asoq$ 01 asoI3 el~p ~HN kIdsIp pue kIlua3al
J. A. MARCOet al.
570
(3H, s, 3-OAc), 1.89 (3H, dq, J = 7, 1.5 Hz, angelate Me), 1.85 (lH, overlapped m, H-12x), 1.81 (3H, dq, J= 1.5, 1.5 Hz, angelate Me), 1.74 (3H, br s, H-19), 1.23 (3H, s, H-16), 1.22 (lH, overlapped m, H-14), 1.00 (lH, overlapped m, H-13), 1.00 (3H, d, J = 7 Hz, H-18); 13CNMR, Table 2. 2,3-Diepiingol7,12-diucetute 8-benzoate (9). Oil, [o(]n -25” (CHCI,; c 3.4); IR vts cm-‘: 3500 (br, OH), 1736, 1721,1705, 1698 (ester and ketone C=O), 1449, 1372, 1277, 1242, 1103, 992, 713; CIMS (CH,) m/z (rel. int.): 555.2582 [M+H]+ (3), 495 [M+HAcOH]+ (59), 433 [Mi-H-PhCOOH]+ (100) 373 [M + H-PhCOOH-AcOH] (5) 3 13 [M + HPhCOOH-2AcOH] (lo), 123 (16) 61 (27). Calcd for C31H3909, A4 = 555.2594; NMR, Tables 3 and 4. Acetylation (Ac,O/pyridine, room temp) gave 9a, oil; [a], - 34” (CHCl,; c 3); IR vzz cm-‘: 1744,1732,1713 (ester and ketone C==O); NMR, Tables 3 and 4. Alkaline hydrolysis of 9 (KzC03, MeOH, room temp), followed by acetylation yielded 9b, oil; [xl,, + 10” (CHCl,; c 0.4); IR vz: cm-‘: 1747, 1739, 1732, 1709 (ester and ketone C==O); NMR, Tables 3 and 4. 2,3-Diepiingol7,12-diacetate 8-isobutyrate (10). Oil; [cI],, -8.5” (CHC&, c 1.4); IR ~2: cm-‘: 3500 (br, OH), 1744, 1728, 17 13, 1698 (ester and ketone C=O), 1470,1438,1370,1242,1154,958,945,868,729; CIMS (CH,) m/z (rel. int.): 521.2772 [M+H]+ (3), 461 [M+H-AcOH]+ (66), 433 [MfH-iBuOH]+ (loo), 373 [M+H-iBuOH-AcOH]+ (lo), 313 [MfHiBuOH-2AcOH] (22), 295 (21) 267 (9), 123 (6), 61 (27). Calc. for C28H4109,M = 521.2750; NMR, Tables 3 and 4. 2-Epiingol3,7,12-triucetate 8-benzoate (11). Oil: [tl]n -41” (CHC&; c 1); IR vzg cm-‘: 1745, 1737, 1730, 1712 (ester and ketone C=O), 1452, 1369, 1273, 1234; CIMS (CH,) m/z (rel. int.): 597.2680 [M+H]+ (8), 537 [M+H-AcOH]+ (85) 475 [M +H-PhCOOH]+ (100) 105 [PhCO]+ (72). Calcd for C33H4,0,0, M, = 597.2699; NMR, Tables 3 and 4. The known compounds were identified by comparison of their NMR spectra with literature data. Acknowledgements-We thank the I.V.E.I. for financial support of this research (project CPE-053). Thanks are also due to Dr J. Jakupovic, Technical University of Berlin, Germany, for helpful discussions and for the exchange of information prior to publication; to Prof. A. D. Kinghorn, University of Illinois at Chicago, U.S.A., for providing us with spectral data of ingol tetraacetate; and to MS Laura J. Gatzkiewicz for revision of the English manuscript.
REFERENCES
1. Mabberley, D. J., The Plant Book. Cambridge University Press, Cambridge, 1987, p. 218.
2. Webster, G. L., Annals of the Missouri Botanical Garden, 1994,81, 33. 3. Evans, F. J. and Taylor, S. E., Progress in the Chemistry of Organic Natural Products, 1983,44, 1. 4. Evans, F. J. and Kinghorn, A. D., Botanical Journal of the Linnaeus Society, 1977, 74, 22. 5. Singla, A. K. and Pathak, K., Fitoterapia, 1990,
61,483. 6. Evans, F. J., ed., Naturally Occurring Phorbol Esters. CRC Press, Boca Raton, FL, 1986. 7. Hickey, T. A., Worobec, S. M., West, D. P. and Kinghorn, A. D., Toxicon, 1981,19,841. 8. Lin, L.-J. and Kinghorn, A. D., Journal of Agricultural and Food Chemistry, 1983, 31, 396. 9. Kinghorn, A. D., Lin, L.-J. and Marshall, G. T., Revista Latinoamericana de Quimica, Supplement 1, 1989, 195.
10. Marco, J. A., Sanz-Cervera, J. F., Yuste, A., Jakupovic, J. and Lex J., Journal of Organic Chemistry, 1996, 61, 1707. 11. Lin, L.-J., Marshall, G. T. and Kinghorn, A. D., Journal of Natural Products, 1983,46, 723. 12. Gotta, H., Adolf, W., Opferkuch, H. J. and Hecker, E., Zeitschrift fur Naturforschung, 1984, 39b, 683. 13. Connolly, J. D., Fakunle, C. 0. and Rycroft, D. S., Journal of Chemical Research (S), 1984,368. 14. Branch, S. K. and Rowan, M. G., Magnetic Resonance in Chemistry, 1992, 30, 632. 15. Lin, L.-J. and Kinghorn, A. D., Phytochemistry, 1983,22,2795. 16. Abo, K. A. and Evans, F. J., Journal of Natural Products, 1982,45, 365. 17. Rizk, A. M., Hammouda, F. M., El-Missiry, M. M., Radwan, H. M. and Evans, F. J., Phytochemistry, 1984, 23, 2377.
18. Khan, A. Q., Rasheed, T. and Malik, A., Heterocycles, 1988, 27, 2851. 19. Gewali, M. B., Hattori, M., Tezuka, Y., Kikuchi, T. and Namba, T., Chemical and Pharmacological Bulletin, 1989, 37, 1547. 20. Khan, A. Q. and Malik, A., Journal of Natural Products, 1990,53, 728.
21. Macromodel, V3.5X version, coupled with Monte Carlo multiconformer search: Mohamadi, F., Richards, N. G. J., Guida, W. C., Liskamp, R., Lipton, M., Caufield, C., Chang, G., Hendrickson, T. and Still, W. C., Journal of Computational Chemistry, 1990, 11,440. 22. Connolly, J. D., Fakunle, C. 0. and Rycroft, D. S., Tetrahedron Letters, 1984, 3773. 23. Morgenstern, T., Bittner, M., Silva, M., Aqueveque, P. and Jakupovic, J., Phytochemistry, 1996,41, 1149. 24. Fakunle, C. O., Connolly, J. D. and Rycroft, D. S., Fitoterapia, 1989, 60,466.
J. A. MARCO et al.
10
RI 1 2 3 4 5 6 7 8 8a
,. ,,,,
Ang Ang Ang Ang Ang Ang Ang H AC
R,
R4
AC H AC AC H AC AC Ang Ang
H OBz OBz OAc H :: OBz OBz
?&,,* 5 R's
-
==
Acd R
OR R’
9
Bz
H
9a 9b 10
Bz AC
AC AC
iBu
H
‘I
11
3-angelate 20-acetate, as deduced from chemical shift considerations. Esters of 5-deoxyingenol have previously been described but are comparatively rare [6]. Compound 8 17-hydroxyingenol 17-benzoate 20angelate, was not present in the latex of E. cunariensis, but was slowly found in some fractions containing ingenol diester (2), 17-hydroxyingenol 3-angelate 17benzoate. This shows once more the ease with which intramolecular acyl migrations occur in ingenol esters, not only during partial hydrolyses [8, 1 I] but also during chromatographic manipulations. The ‘H NMR data of 8 and its acetate 8a are described in the Experimental; their 13CNMR data are given in Table 2. High-resolution NMR data were not always provided in earlier reports of compounds l-5. We thus
report the ‘H NMR data for all ingenane derivatives isolated in the present work, including the known ones, in Table 1, as well as the corresponding ‘jC NMR data in Table 2. The configurations of all stereogenic centres have been reconfirmed with the aid of NOE measurements, whereas the carbon signals have been unequivocally assigned using HMQC/HMBC experiments. The latter further provided unequivocal evidence for the locations of the ester residues through observation of long-range H-C-GCOR correlations [13, 141. The CIMS data of compound 9 (highest mass peak at m/z 555) indicate the molecular formula C31H3809. The NMR data (Tables 3 and 4) show the presence of a benzoate and two acetate groups. The hydrogen and carbon connectivities deduced from HMQC and HMBC experiments aided in establishing the lathyrane framework and allowed the conclusion that 9 is structurally close to a triester of ingol bearing two acetoxy groups at C-7 and C-12 and a benzoyloxy residue at C-8. In fact, acetylation of 9 gave 9a, which has NMR data similar to those of ingol 3,7,12-&iacetate 8-benzoate [15]. Several NMR features, however, that 9 is not an ingol derivative. A most notable point is the value of J2,3 (5.5 Hz), which is quite different from that observed in true ingol esters (ca 8.5 Hz). Further relevant differences are observed in the chemical shifts of the H-l protons, which appear in the spectra of ingol derivatives at ca 1.7CL1.65 and 2.8g2.70 ppm [9, 15-201, a marked difference from those measured in 9 (Table 3). Finally, alkaline hydrolysis of 9 and subsequent acetylation yielded a tetraacetate 9b, the spectral data of which are different from those of ingol tetraacetate [9]. Thus, compound 9 is a stereoisomer of ingol 7,12-diacetate 8-benzoate. The similarity of chemical shift and coupling constant values in the fragment C-5 to C-13 of 9 with those published for ingol esters [9, 15-201 led us to conclude that configurational and conformational aspects of the 1 l-membered ring are essentially the same in all these compounds. The stereochemical differences were thus centred on the five-membered ring, most likely at C-2 and/or C-3. Unfortunately, the NOE data were not conclusive in the present case. For instance, a NOE was visible between the methyl group at C-2 (H-16) and both H-3 and 3-OH. Further NOES were observed between H-2 and H-3, between H-3 and H-5, and between 3-OH and H-5. In view of this situation, we resorted to molecular modeling using ‘MacroModel’ [21]. Since the chemical shift values of the carbon atoms from C-6 to C-14 are essentially the same as in ingol esters [9, 18-20, 221, we maintained the p configuration for the epoxide ring (inversion to an a-epoxide would cause appreciable changes in these values, most particularly in the signals from carbons near to the five-membered ring). We then considered all four possible stereoisomers of ingol tetraacetate at C-2/C-3 (A-D, see Scheme 1) and used the aforementioned program to optimize their geometries. This was performed through a Batchmin
Table 1. ‘H NMR data of ingenane H
1
2*
1 3 4-OH 5 I 8 11 12a
6.02 br d (1.5) 5.55 S 3.45 S 3.89 br d (7)t 6.10 br d (4) 4.09 br dd ( 12; 4) 2.49 m 1.76 ddd (16; 6.5; 5) 2.22 ddd (16; 8.5; 2.7) 0.69 ddd (8.5; 8.5; 6.5) 0.95 dd (12; 8.5) 1.03 S 1.06s
6.02 5.57 3.60 4.03 6.00 4.33 2.55 1.90
128 13 14 16 17 18 19 20 OAc OAng
0.96 1.78 4.74 4.47 2.04 6.15 1.99 1.90
d (7) d(1.5) br d (12.5) br d (12.5) s (3H) qq (7; 1.5) dq (7; 1.5) dq (1.5; 1.5)
br d (1.5) S s br s br d (4) br dd (12; 4) m WlT
derivatives
3*
4
5
6
6.02 brd(1.5) 5.57 s
6.03 br d (1.5) 5.52 s 3.50 S 4.06 br s 6.06 br d (4) 4,14brdd(12;4) 2.52 m 1.75 ddd (15.5; 7; 6.5) 2.25 ddd (15.5; 8.5; 3) 0.69 ddd (8.5; 8.5; 6.5) 0.95 dd (12; 8.5) 1.04s 1.08 s
6.08 5.04 3.30 5.42 6.23 4.24
2.41 ddd (15.5; 9; 2.8) 1.00 mf[
2.39 ddd (15.5; 9; 2.8) 1.OOrnq
6.02 brd(1.5) 5.55 s 3.45 s 3.88 br d (5)f 6.10brd(4) 4.19 br dd(12; 4) 2.49 m 1.85 ddd (16; 6.5; 6.5) 2.30 ddd (16; 8.5; 3) 0.95 rn7
1.22 ml
1.22 dd (12; 8.5) 1.21 S 4.52 d(11.8) 4.36d(11.8) 0.98 d (7) 1.78 d(1.5) 4.66 br d (12.5) 4.38 br d(12.5) 1.98 s (3H) 6.13 qq (7; 1.5) 1.98 dq(7; 1.5) 1.88 dq (1.5; 1.5)
1.15 dd (12; 8.5) 1.12 S 4.26 d(11.8) 4.12 d(11.8) 0.97 d (7) 1.79d(1.5) 4.74 br d (12.5) 4.47 br d(12.5) 2.05 s (6H) 6.17 qq(7; 1.5) 2.00 dq (7; 1.5) 1.91 dq(1.5; 1.5)
1.22s 4.57 d (11.8) 4.36d(11.8) 0.98 d (7) 1.78 d(l.5) 4.06 br s (2W 6.14qq(7; 1.5) 2.00 dq (7; 1.5) 1.90 dq (1.5; 1.5)
6 in ppm and J (parentheses) in Hz (400 MHz, CDCl,, 22”). * OBz: 8.03 dd (2H; 8; 1.5), 7.56 tf (IH; 8; 1.5), 7.45 t (2H; 8). t The 5-OH appears at 6 3.60 d (7). 1 The 5-OH appears at 6 3.50 br d (5). §(5aH); 5/IfH appears at 6 2.36 br d (18.5). 7 Overlapped signal.
l-7
3.86 6.08 4.29 2.52 1.90
br s br d (4) br dd (12; 4) m my
0.96 d (7) 1.79 brs 4.14 br s (2H) 6.16 qq (7; 1.5) 2.01 dq (7; 1.5) 1.92 dq(1.5; 1.5)
7 br br br br br br
d (1) s s s d (4) dd (12; 4)
2.54 m 1.75 ddd (16; 6.5; 6) 2.28 ml
6.00 br s 5.01 S 2.70 br s 2.52 d (18.5)s 6.05 br f (2) 4.12brd(11.5) 2.40 m 1.79 ddd (15.5; 7; 6) 2.17 ddd (15.5; 8; 3)
0.70 ddd (9; 8.5; 6.5) 0.96 dd (12; 8.5) 1.05 S 1.07 s
0.70 ddd (8; 8; 7) 0.95 my
0.98 d (7)
0.96 d (7)
1.76 d(1) 4.60 br d (12.5) 4.19brd(12.5) 2.24 s, 2.00 s (2 x 3H) 6.10 qq (7; 1.5) 1.96 dq (7; 1.5) 1.89 dq (1.5; 1.5)
1.78 brs 4.36 br s
F B 2 z g a c B v: @ ,3 ac. f % 3
1.04s 1.10s
(2H) 2.05 6.16 2.00 1.91
s (3H) qq (7; 1.5) dq (7; 1.5) dq (1.5; 1.5)
S h % z 5 a a” g ,T. S 2.
Table 2. “C NMR data of ingenane
derivatives
lga
C
1
2
3
4
5
6
7
8
8a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 OAc
132.2 136.0* 82.7 84.9 74.8 135.9* 129.5 43.6 206.3 72.1 38.5 31.1 23.3 23.1 24.0 28.5 15.5t 17.3 15.6t 66.8 171.1 21.1 168.4 140.0, 127.1 20.8, 16.0
131.6 136.2 82.2 84.9 76.6 139.7 127.2 43.2 205.9 72.0 38.4 30.9 24.3 23.5 27.7 24.6 66.2 16.9 15.6 67.2
131.6 136.2 82.3 84.9 74.7 136.4 128.2 43.2 205.5 72.0 38.5 30.9 24.3 23.5 27.7 24.5 66.1 16.9 15.6 66.5 170.9 21.0 168.2 140.0, 20.7, 166.7 133.0, 129.5,
131.7 136.4* 82.5 84.9 74.9 136.3* 128.7 43.3 205.5 72.1 38.5 30.9 24.3 23.5 27.5 24.4 65.6 17.0 15.6 66.7 171.4, 171.0 21.0(x2) 168.3 140.2, 127.1, 20.8, 16.0
132.1 135.7 82.5 84.7 77.1 139.0 128.6 43.5 206.6 72.0 38.3 31.1 23.3 23.0 24.0 28.5 15.5 17.3 15.5 67.5
132.0 135.6 81.8 85.8 74.9 133.3 131.7 43.6 205.6 72.0 38.6 31.1 23.1 22.9 24.3 28.4 15.4* 17.0 15.5* 65.9 170.8, 170.7 20.9, 20.8 169.1 139.1, 127.4 20.7, 15.8
132.3 136.1 85.7 80.5 43.7 132.4 128.8 44.2 208.4 75.0 37.0 31.5 23.7 23.2 23.6 28.6 15.5* 18.2 15.6* 68.5 170.8 21.0 168.6 139.9, 127.1 20.7, 15.9
128.9 139.4 80.1 84.4 73.7 137.4 126.2 43.6 206.0 72.5 39.6 30.7 24.2 23.5 27.7 24.4 66.2 16.9 15.3 65.8
131.8 135.7 82.0 85.7 74.6 133.8 130.4 43.2 204.3 71.8 38.6 30.9 24.1 23.5 28.0 24.4 66.2 16.6 15.3 64.9 172.3, 21.1, 167.2 138.4, 20.5, 166.7 133.0, 129.5,
OAng
OBz
168.4 139.8, 20.8, 166.7 133.0, 129.6,
127.2 15.9 130.3 128.4
127.0 15.9 130.2 128.3
168.5 140.0, 127.2 20.8, 16.0
-
6 in ppm (100 MHz, CDCl,, 22”). Signals have been assigned by means of 2D-NMR experiments. *,t Signals with the same superscript may be interchangeable within the same column.
167.9 138.4, 20.5, 166.9 133.0, 129.5,
127.6 15.7 130.1 128.4
170.6 20.7 127.5 15.7 130.2 128.4
Table 3. ‘H NMR data of lathyrane H la 1B 2 3 5 7 8 9 11 12 13 16 17 18 19 20 OAc
OBz
9*
9a
9b
1.92 rn§ 2.20 ml 1.92 rn§ 3.98 f (5) 6.02 br s 5.24 br s 4.80 dd(10.5; 1.5) 1.40 dd(10.5; 9) 1.2Odd(ll; 9) 4.90 dd(l1; 4) 2.97 dq (4; 7) 0.98 d (6.5) 2.12 br s 1.11 S 0.80s 1.03 d (7) 2.05 s (3H) 2.04 s (3H)
2.01 dd(13.5; 7) 2.26 dd(13.5; 10.5) 2.10 mQ 5.29 d (5.5) 5.68 br s 5.30 br s 4.82 dd(10.5; 1.5) 1.37 dd(10.5; 9) 1.24dd(ll;9) 4.92 dd(ll; 4) 2.99 dq (4; 7) 0.93 d (7) 2.14 br s 1.16s 0.83 s 1.07 d (7) 2.11 s (3H) 2.09 s (3H) 2.05 s (3H)
2.00 2.25 2.10 5.28 5.63 5.19 4.56 1.20
dd(13.5; dd(13.5; mQ d (5.5) br s brs dd(10.5; r (10.5)
(2H) 4.86 2.91 0.92 2.07 1.11 0.84 1.05 2.10 2.09 2.08 2.00
dd(10.5; 4) dq (4; 7) d (7) br s s s d (7) s (3H) s (3H) s (3H) s (3H)
7.96 dd (2H; 8; 1.5) 7.52 ff (1H; 8; 1.5) 7.40 t (2H; 8)
7.98 dd (2H; 8; 1.5) 7.56 tt (1H; 8; 1.5) 7.43 t (2H; 8)
6 in ppm and J (parentheses) in Hz (400 MHz, CDCI,, *3-OH: 2.50 br d (5). t 3-OH: 1.65 d (5). $ OiBu: 2.48 qq (7; 7), 1.13d (3H; 7), 1.1 I d (3H; 7). § Overlapped signal. YjNon-first-order signal.
22”).
derivatives
9-11 lW,S
7) 10.5)
1.5)
_
1.95 rn§ 2.25 ml I .95 m$ 4.02 t (5) 6.00 br s 5.20 br s 4.60 dd(10.5; 1.5) 1.28 dd(10.5; 9) l.l4dd(ll, 9) 4.86 dd(l1; 4) 2.95 dq (4; 7) 1.02 d(6.S) 2.09 br s 1.09 s 0.84 s l.O4d(7) 2.12 s (3H) 2.09 s (3H)
11 2.10 mp 2.10 rn§ 1.90m 5.05 d (8.8) 5.65 br s 5.08 d(l.5) 4.80 dd(l1; 1.5) 1.46 dd(l1; 9) 1.15 dd(l1; 9) 4.90 dd (11; 4) 2.98 dq (4; 7) 1.03 d(7) 2.13 br s 1.15s
0.82 s 1.OS d (7) 2.13 s (3H) 2.08 s (3H) 2.04 s (3H) 8.00 dd(2H; 1.5) 7.57 tt (IH; 8; 1.5) 7.44 t (2H; 8)
6 % $ z !z a i; F ‘< ti a f 3 3 3 h d z ? Q “a as 2. 3 2.
568
J. A.
MARCO
et
al.
Table 4. 13C NMR data of lathyrane
derivatives
9-11
C
9
9s
9b
10*
11
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 OAc
32.1 33.0 76.4 72.5 116.8 137.4 77.3 72.1 24.7 19.3 30.7 70.7 43.2 207.8 73.1 12.0 17.5 29.1 16.1 13.3 170.5, 21 .o, 165.8 133.2, 129.5,
32.7 32.5 77.2 70.7 115.2 139.1 76.8 72.0 24.8 19.4 30.8 70.5 43.4 207.4 73.0 12.3 17.6 29.1 16.2 13.2 170.3, 21.0, 165.8 133.2, 129.5,
32.7 32.5 77.1 70.7 115.4 138.8 76.5 71.4 24.5 19.2 30.5 70.5 43.3 207.3 73.1 12.3 17.6 29.0 16.1 13.2 170.4, 170.3, 169.6, 169.2 21.0, 20.9 ( x 2), 20.6
32.1 32.9 76.6 72.4 116.6 137.6 76.7 71.4 24.6 19.2 30.6 70.7 43.1 207.6 73.1 12.0 17.6 29.1 16.3 13.3 170.4, 169.8 21.1,21.0
31.1 31.0 80.4 69.8 117.0 139.7 77.3 71.6 25.2 19.6 30.8 70.7 42.9 207.3 71.4 16.1 17.3 29.2 16.1 13.5 170.8; 21.0 165.7 133.2, 129.6,
OBz
169.9 20.9 129.7 128.4
169.5, 169.0 20.8, 20.6 129.7 128.4
6 in ppm (100 MHz, CDCl,, 22”). Signals have been assigned *OiBu: 176.3, 33.9, 18.8, 18.7.
A (8-9 Hz)
B (8-9 Hz) 0
0
IllI.
& 4 2
Ri c Scheme
R6
(5.5 Hz)
1. Calculated
& values stereoisomers
D (1.5 Hz) (in parentheses) A-D.
for ingol
search and energy minimization [21], which provided the lowest energy conformers for each possible diasteroisomer. For two of them, the ingoltype derivative A and its 2-@isomer B, J2,3 values in the range 8-9 Hz were calculated. For the 2,3diepiisomer C, the predicted J2,3 was 5.5 Hz, while for the 3-@isomer D, a J2,3 value of ca 1.5 Hz was found. Thus, we concluded that a 2,3-diepiingol derivative is conformational
by means of ZD-NMR
170.3, 169.9 ( x 2), 20.7 129.7 128.5
experiments.
present in the case of 9, and that is therefore 2,3diepiingol 7,lZdiacetate 8-benzoate. The interatomic distances and the NOES predicted for this structure were in good agreement with the actual observations. According to NMR evidence, compound 10 is very close to 9. Chemical shifts and coupling constants are almost identical in both compounds (Tables 3 and 4), the only difference being the presence of an isobutyrate group in 10 instead of the benzoyl group found in 9. Compound 10 is, therefore, 2,3-diepiingol 7.12-diacetate 8-isobutyrate. Compound 11 is closely related to 9a, as evidenced from NMR data. All spectral data, including heteronuclear 2D NMR measurements, point to an ingoltype tetraester bearing acetoxy groups at C-3, C-7 and C-12, and a benzoyloxy group at C-8. One main difference with 9a is the coupling constant J2,3 = 8.8 Hz. However, 11 is not an ingol ester, in view of the chemical shifts of the H-l protons (Table 3) and of the five-membered ring carbons (Table 4) [9, 18-20, 221. On the basis of the aforementioned molecular mechanics calculations [21] and of the value of J2.3, we concluded that 11is a stereoisomer of ingol displaying the B-type configuration in the five-membered ring. Compound 11 is thus 2-epiingol 3,7,12-triacetate 8benzoate. This product represents the second report in the literature of a 2-epiingol derivative. The first members of this compound class have been described very
OI’Z ‘(WO-S ‘S ‘HE) OZ’Z ‘(dZI-H ‘ZH L’Z ‘6 ‘91 = f ‘ppp ‘HI) OP’Z ‘(II-H ‘u ‘HI) PS’Z ‘(HO-P ‘S 44 ‘HI) SZ’E ‘?OZ-H ‘ZH S’ZI = f ‘P 19 ‘HI) SZ’P ‘(qLI-H ‘ZH 8’11 = f ‘P ‘HI) 8f’P ‘(“OZ-H ‘“LI-H ‘8-H ‘~4 A9 ‘HE) 8P’t ‘(f-H ‘S 19 ‘HI) S6’P ‘(S-H ‘S 19 ‘HI) OP’S ‘(D!u -yaIO aleIa%lC?‘ZH 5.1 ‘L =f ‘66 ‘HI) ZO’9 ‘(I-H ‘ZH 5‘1 =f‘P”9’HI)90’9‘(L-H‘ZHS’P=f“P~9‘HI)PZ’9 ‘(~~~WLlOJtWl2Ui‘ZH 8 = [ ‘1 ‘HZ) fP’L ‘(3!~WIO.Wv.ivd ‘ZH S’I ‘S’L = f ‘11‘HI) PS’L ‘(~~Jl?LUO.It?-0yW‘ZH S’I ‘S’L = f ‘pp ‘HZ) 20’8 9 (ZHYI OOP “13CI3) ‘dKN H, :k?g ahe8 (dwal ulo0.1 ‘au!p!lkd/@V) uo!le[6~a~V ‘Z aIqeL ‘XWN 3<, :(81-H ‘ZH L = f ‘p ‘HE) 56’0 ‘(EI-H ‘W paddeIlaAo ‘HI) S6’0 ‘(PI-H ‘ZUpaddeIJaAo ‘HI) ZZ’I ‘(91-H ‘S ‘HE) ZZ’I ‘(al4 aWa%ue ‘61-H ‘.s49 ‘H9) 08’1 ‘(ZIZI-H ‘LUpaddepaAo ‘HI) 28.1 ‘(aK aleIa%IC? ‘ZHS’1‘L=f‘~~‘Hf)68’I‘(dZI-H‘1I-H‘~~9‘HZ) OP’Z ‘(HO-S ‘ZH 01 = I ‘P 19 ‘HI) SP’E ‘(S-H ‘ZH 01 = f ‘P 19 ‘HI) 99.f ‘(Ho-f ‘s 19 ‘HI) 06.f ‘(8-H ‘ZH S’P ‘ZI = f ‘PP “9 ‘HI) OE’P ‘(f-H ‘S 19 ‘HI) ZE’P ‘(HO -ti ‘S 49 ‘HI) OP‘P ‘(qLI-H ‘ZH 8’11 = f ‘P ‘HI) SP.P ‘(“LI-H ‘ZH 8’11 = f ‘P ‘HI) SS’ti ‘(‘OZ-H ‘ZH f 1 = f P 19 ‘HI) 9S’P ‘(“OZ-H ‘ZH El = f P ‘HI) 893 ‘(1-H S’I = f ‘p A9 ‘HI) 88’S ‘(3!UyalOall?Ia%Ur! ‘ZH 5.1 ‘ZH
‘L = f ‘M ‘HI) ZO’9 ‘(L-H ‘ZH ST = f ‘P 49 ‘HI) f0’9 ‘(3!~l?UIOD?-Vjc9U4 ‘ZH
5.1
‘S’L
=
f
‘ZH ‘11
8 =
f
‘HI)
‘j ‘HZ) PS’L
EP’L
‘(3!l~uIO~l?-vAVd
‘(3!)EuIO.lW~jAO
‘ZH
S’I ‘S’L = f ‘PP ‘HZ) 20’8 9 (ZHIIV OOP ‘E13a3) XKN H, %IL ‘S96‘9PIl ‘8921 ‘LLEI ‘ZSPI ‘OOLI ‘SILI‘(HO ‘J9) OfPf :,-m3 ::* XI f(6’Z 3 %H3) .S’La[ml ‘I.‘0 ‘(8) alv@lv-OZ awozuaq-LI ]OUd%4~dXOAp~H-L 1 ‘2 PUC I sa1qKL ‘WYN t06SZ’LSP = J4’ ‘90’EHLi3 “?I PVT.) ‘(6f) 19‘(SZ) 101 ‘(PC) + [03-HOSUV-H03V-OSH-H + K] 692 ‘(t+) + [HOBUV-H03VQzH-H + K] 6LZ ‘(001) + [HOSUV-HOY-H + W] L6Z ‘(P) +[HO~uV-O’H -H + IX] 6ff ‘(S I) +[HOzuV-H + W] LSE ‘(9) +[HOT -O’H-H+ K] 6Lf ‘(9) +[HOW-H+ W] L6f ‘(Z) + tOiH-H + k’i] 6fP ‘(9) +[H + K] ZO9Z‘LSP :(‘lu! ‘IaJ) z/m (‘H3) SE’K-tf88 ‘9f6 ‘PEOI ‘SSI I ‘SEZI ‘9Lf I ‘ESPI ‘(0=3auolaXPu~Jalsa)P691 ‘8691 ‘LILI ‘9fLI ‘(HO ‘A9) OSPE I,-‘=’ :;A XII t(S.0 3 %H3) &‘I + a[;~] ‘ITO ‘(L) aztwwv-OZ ajv@4v-f ~ouaGu~iCxoaa-S ‘130 (dtuaj u1o0.1 1(q pau!elqo 13npold aq$
‘au!p!l,Jd/@3V)
uog~Il(la~
Yl!M 3’I.L Pue Xk’IN dq I’WuaPI ‘Z PUE I SaIqel ‘WYN 2479Z’SIS = Jl’ ‘806EH6Z3 “OJ PT3 ‘(85) 19 ‘(OS) IO I ‘(OZ) +[03-HOZUV-H03VZ-H + JX] L9Z ‘(06) + [HOBUV-HOWZ-H + W] 562 ‘(00 I ) + [HOZUV-HOY-H + I4] SSf ‘(9) + tH08uV-H + K] SIP‘(S) +[HOzV-H+R] SSP ‘(9) +[H+kT] 099Z’SIS :(.lu! ‘Ial) z/U’ (*H3) SKI3 tZ68 ‘906 ‘PEOI ‘691 I ‘ZPZI ‘ELEI ‘Z9PI ‘SS91 ‘(c)---3 auolay Pue Jalsa) 5691 ‘6OLI ‘9fLI ‘OPLI ‘(HO ‘AS)OZPE :,-u3 :;A XI f(f 3 ?3H3) ,&I + a[7J]‘I!0 ‘(9) ~~V~~WV~~Z‘S-~~V~~UV-~-~OU~~U~ J~JJE z 8u!u!aluo~ ~“3 autos u! aq$u! IuasaJd kllT?!l!U! $~II f) s pue (%u L) p ‘(%w
3gdel8olewo.nj~
~~uLIoJ~IMOIS se~lnq‘Slx?ll~a
$0~ SBM 8 punoduIo3
SL) Z ‘(SW OZZ) 6 ‘(%w SI) 01 ‘(8m 9LI) E ‘(8m OLI) 1 ‘(8u1 LI)11 ‘(%IpI)L‘(th 8)9 :4pe1od %u!SsalDU!
30 laplo 8u!MolIo3 aql u! uurnIo3 IaS eDy!s aql ~uo~3 pa]nIa aJaM -lallvI aqL ‘lxal ayl u! pauoguauI spunod -u103 aql30 pue sauad.tal!n 30 slunoruv ~~uo!l!pp~ 30 uo!]eIos! aqJ paMoIIe ?.ry~ ‘3TdH lo/pue 37~ ,dald kq ‘kEssaDau alaqm ‘pay!md _taqlmn3a.taM s_13awpatu -law! ayL .(ozig + I:OI #la-auexay ql!~ uognla) Ia% e~I!s uo 33 01 pal3a[qns SBM ‘13 aIpp!w aql 'MoIaq paq!l%ap se suogwedas ~!ydeBoleur -oJy:, laqlJn3 01 paparqns stz~ (8 11 v3) uog -3~13 aipp!w aqL .AIaAgDadsaJ ‘(Ioqloydna PUG loydna @~eur) sauadlalpl UOUI~IO~pue spunodmo3 pauyap -II! ‘IeIod pau!eluoD AIuo LayI SE pap.w3s!p aJaM sq HOaM pue .lall?M ayl ‘HOan Q!M Qeuy pue (f:L) O’H-H@‘m ql!M Uaql ‘JaleM ql!M @sJy (WJ e lapun palnIa pue [a% KXJS z-s' 1) aJnssaJd IV @Is 30 adlCl auuzs aql ypm paIIy uuInIo3 3gde.Bolewo~q~ I! 30 doI aql uo paDe[d SBM pau!elqo Ie!laleuI kap -Mod aqJ_ ‘on3viI UJ paleu!uI!Ia kp$Ol uayl SBM luaA[os ayL jOI] (wqxa 30 %/Ias w!I!s 30 8 f) pappv SI?M Ia e~I!s aseyd-aslaAa1 ‘HoaM 30 lunome unn.u!u!ru ayl u! po syl Bu!~~oss!p Iaj3V ‘(2 9I a~) Ie!Jaleru i(po ‘qS!l!qM B ah&i On3vn u! luaA[os aql30 uoge.IodeAcJ ~o!~e~lIy icq pawuywga SBM q3!y~ '[g]sauadJa$g uoun.uo~ 30 alel!dpald a)!qM ‘snou$nIoA 01 as!1 aAe2 dwal WOOJ 01 BwIoo3-al pun (I I) Hoam $0~ u! xalel agl30 uo~~n[oss~a ~kydvA6ojvuroryJ puv uo~j.3v~jx~ ‘EJ3!JJUauaJ‘.n?unnf) (3 06 113) S,NG’~AVUV3
ap s!vdIEW u! pa$Da[IoD SCM 30 Xalt21 alJJ_ ‘~“&0jVtU lUV\d
‘3
May ‘slx!UJ OZH-HOaw ql!M UO!ln[a ‘(WUJ 8 X OSZ) 8-dll q”osoJYB!‘I TIdH t(61 LLO W’) Wak’I Ia e~!I!s paz!ue[!s Ia ?X!I!Saseyd-as.IaAaJ t(u~ti OOZI)S az!s aIDp.wd) gV a!uxayDpns Ia% EXI!S :33 alnssaJd ~XUJOU f,ZZ 1~ $I~HD :suogelo~ Iwgdo tlalaruowads SSl2IU
V886S
pJT?y%?&llaIMaH
?H3
‘SW13
fa%a.Ia
-3aJ sv SI”u%!s JuaAIos ‘(&,) ZHYI 001 Put! (H,) ZHI4 009 1~ pvayaqoJd as.IaAu! ue ql!~ t13a3 :?HJN
-Ied asayl u! aIqes!Apv aq ~y8!u1 uo!s!Aal pnwu~s v ‘ZH f’[ 10 s’s SF E’Zf alaym spunodwo:, ayl ~03 iCIay!Ilou s! s!yl ‘.IaAaMOH ‘.Iay$o yxa 01 nI!ur!s al!nb 0sIe ale dI-H pw ;0I-H 30 sanIeA 13!ys p23!way3 ayl asu!s ‘saAgeA!Jap 10%~~dl!I!qeqold IIe u! an? ZH S’g VJ s! E‘Zf alaqM spunoduro3 paysgqnd Qsno!Aald \Ie ‘[fZ] uopda3xa pauoguauralo3t! aql ql!M ‘zH S’OTS.8 30 aWelt? U!I@M sailas aql q%no.rq] ~ue~suo~ iCIIc3!13wd u!erual ppoqs ~uelsuo~ %.nIdnoa pauoguaura.to31? ayl ‘sanp!sal Jalsa ayl 30 amleu ayl u! Quo lag!p spunodwo:, asaql30 II” ‘aId!c)u!.‘d u! ‘aDu!S .[pZ ‘f I] ZH f’1 Pue [VI] ZH S’S ‘[OZ-SI ‘61 ZH S’OT S’8 :SaA!lzA!JaP IO&I! pawnsse sno!.reA 103 paqsgqnd dIsno!AaJd alaM sanIeA E‘Zf 8u~moIlo3 aql ‘aDuelsu! loa %!uoguaur yl.10~ s%u!puy papla@ elep pays!Iqnd ayl30 uop~u! -tuexa In3a.w3 V ‘amwalg aql u! pal1oda.x Qsno!A -aId alaM IO%U!30 slaur!da ou ‘s!y~ ~0.13 ap!sV .[fZ] ~1 30 asoq$ 01 asoI3 el~p ~HN kIdsIp pue kIlua3al
J. A. MARCOet al.
570
(3H, s, 3-OAc), 1.89 (3H, dq, J = 7, 1.5 Hz, angelate Me), 1.85 (lH, overlapped m, H-12x), 1.81 (3H, dq, J= 1.5, 1.5 Hz, angelate Me), 1.74 (3H, br s, H-19), 1.23 (3H, s, H-16), 1.22 (lH, overlapped m, H-14), 1.00 (lH, overlapped m, H-13), 1.00 (3H, d, J = 7 Hz, H-18); 13CNMR, Table 2. 2,3-Diepiingol7,12-diucetute 8-benzoate (9). Oil, [o(]n -25” (CHCI,; c 3.4); IR vts cm-‘: 3500 (br, OH), 1736, 1721,1705, 1698 (ester and ketone C=O), 1449, 1372, 1277, 1242, 1103, 992, 713; CIMS (CH,) m/z (rel. int.): 555.2582 [M+H]+ (3), 495 [M+HAcOH]+ (59), 433 [Mi-H-PhCOOH]+ (100) 373 [M + H-PhCOOH-AcOH] (5) 3 13 [M + HPhCOOH-2AcOH] (lo), 123 (16) 61 (27). Calcd for C31H3909, A4 = 555.2594; NMR, Tables 3 and 4. Acetylation (Ac,O/pyridine, room temp) gave 9a, oil; [a], - 34” (CHCl,; c 3); IR vzz cm-‘: 1744,1732,1713 (ester and ketone C==O); NMR, Tables 3 and 4. Alkaline hydrolysis of 9 (KzC03, MeOH, room temp), followed by acetylation yielded 9b, oil; [xl,, + 10” (CHCl,; c 0.4); IR vz: cm-‘: 1747, 1739, 1732, 1709 (ester and ketone C==O); NMR, Tables 3 and 4. 2,3-Diepiingol7,12-diacetate 8-isobutyrate (10). Oil; [cI],, -8.5” (CHC&, c 1.4); IR ~2: cm-‘: 3500 (br, OH), 1744, 1728, 17 13, 1698 (ester and ketone C=O), 1470,1438,1370,1242,1154,958,945,868,729; CIMS (CH,) m/z (rel. int.): 521.2772 [M+H]+ (3), 461 [M+H-AcOH]+ (66), 433 [MfH-iBuOH]+ (loo), 373 [M+H-iBuOH-AcOH]+ (lo), 313 [MfHiBuOH-2AcOH] (22), 295 (21) 267 (9), 123 (6), 61 (27). Calc. for C28H4109,M = 521.2750; NMR, Tables 3 and 4. 2-Epiingol3,7,12-triucetate 8-benzoate (11). Oil: [tl]n -41” (CHC&; c 1); IR vzg cm-‘: 1745, 1737, 1730, 1712 (ester and ketone C=O), 1452, 1369, 1273, 1234; CIMS (CH,) m/z (rel. int.): 597.2680 [M+H]+ (8), 537 [M+H-AcOH]+ (85) 475 [M +H-PhCOOH]+ (100) 105 [PhCO]+ (72). Calcd for C33H4,0,0, M, = 597.2699; NMR, Tables 3 and 4. The known compounds were identified by comparison of their NMR spectra with literature data. Acknowledgements-We thank the I.V.E.I. for financial support of this research (project CPE-053). Thanks are also due to Dr J. Jakupovic, Technical University of Berlin, Germany, for helpful discussions and for the exchange of information prior to publication; to Prof. A. D. Kinghorn, University of Illinois at Chicago, U.S.A., for providing us with spectral data of ingol tetraacetate; and to MS Laura J. Gatzkiewicz for revision of the English manuscript.
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