The molecular and crystal structure of the new nortriterpene 24-nor-3a,l1a-dihydroxy-lup-20(29)-en-28-oic acid isolated from the
Araliaceae Acanthopanax trifoliatus has been determined on the
basis of X-ray analysis of its methyl ester

Doris Pfeiffer

Gunter Adam

Leo Kutschabsky

Manfred Lischewski

Pham Dinh Ty

English

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CROATICA CHEMICA AC TACCA-1594CCACAA 58 (4) 427-434 (1985)YU ISSN 0011-1643UDe 547.9Original Scientific PaperMolecular and Crystal Structure of a New 24-nor-TriterpenoidCarboxylic Acid from Acanthopanax Trifoliatus+*Leo Kutschabsky and Doris PfeifferCentral Institute of Molecular Biology of the Academy of Sciences of the G. D. R.,Berlin-Buch, G. D. R.andManfred Lischewski, Pham Dinh Ty and Gilnter AdamInstitute for Plant Biochemistry, Academy of Sciences of the G. D. R., Hane (Stuile),G. D. R.Received April 11, 1985The molecular and crystal structure of the new nortriterpene24-nor-3a,l1a-dihydroxy-lup-20(29)-en-28-oic acid isolated from theAraliaceae Acanthopanax trifoliatus has been determined on thebasis of X-ray analysis of its methyl ester.INTRODUCTIONRecentlyt " we reported on the isolation and structure of same new tri-terpenes of the lupane series from the plant Acanthopanax trifoliatus (L.)Merr. (Araliaceae), used in the folk medicine of Southeast Asia as a drugwith Ginseng-like activity".One of these constituents was a new 24-nor lupane derivative for which,on the basis of physical data, the structure 24-nor-3a, Hn-dihydroxy-lup-20(29)-en-28-oic acid (1) was proposed-. .J,+ Dedicated to Professor Mihailo Lj. Mihailović on the occasionbirthday.* Part 15 in the series Natural Products from Vietnamese Plants.For part 14 see lit. 1.of his 60th. L~!fi428 L. KUTSCHABSKY ET AL.In this communication we describe the detailed molecular and crystalstructure of this constituent by the X-ray analysis of its corresponding methylester 2.EXPERIMENTALFor the X-ray analysis a single crystal of 21, 0.3 X 0.4 X 0.7 mm large, obtainedfrom ether-n-hexane, was used. Crystal data: orthorhombic, space group P212121;unit cell a = 8.437(4), b = 22.340(8), c = 14.096(5) A; Z = 4; De = 1.179 g/cm-1.The intensities of 2322 independent reflections up to 26 = 48° were collected inthe w/26 sean mode on a Hilger and Watts four-circle diffractometer with gra-phite-monochromated MoK. radiation. The intensity data were corrected for Lo-rentz- and polarisation effects. Neither absorption nor extinction corrections wereapplied.The structure was solved by direct methods with the computer programMULTAN 785• The E-map revealed nearly all nori-hydrogen atoms. The positionsof the remaining non-hydrogen atoms were determined by a difference Fouricrsynthesis after some cycles of the fullmatrix least squares refinement with SHELX766• At the discrepancy factor of R = 0.098 the hydroxyl H-atoms were located ona difference Fourier map while the remaining hydrogen atoms were generated geo-metrically. The final weighted anisotropic full-matrix refinement with fixed iso-tropic contributions of the H-atoms converged to R = 0.072 for 1943 observedreflections with /Fo/ > 30'. The weighting scheme was w = 1/«0' (F.))2 + 0.00055/Fo/2.The final atomic positional parameters are listed in Table 1. Bond distances, bondangles and endocyclic torsion angles are given in Tables II, III and IV, respectively.*Figure 1 shows the molecular structure of 2. The 23-methyl group occupies theequatorial 4a-position. The rings A, B, C and Dare almost chairs, ring E adopts aFigure 1. Molecular structure of the methyl ester 2.* Lists of anisotropic thermal parameters for non-hydrogen atoms, H-atomparameters and torsion angles have been deposited with the British Library LendingDivision as Supplementary Publication No. SUP. Copies may be obtained throughthe Executive Secretary, International Union of Crystallography, 5 Abbey Square,Chester CHl 2HU, England,TRITERPENES 429TABLE IFractionaL Atomic Coordinates oj 2 (e.s.d.'s in Parentheses) and EquivaZentIsotropic Temperature Factors (A2) Ueq = 1/3 ~ ~ Uijai*, aJ*a!aJ1 JAtom xi a (G"") Y Ib (O--) zle (6"")C(1) 0.8043(7) 0.2473(2) 1.2888(4)C(2) 0.8715(8) 0.2828(3) 1.3723 (4)C(3) 0.7697(7) 0.3365(3) 1·.3984(4)C(4) 0.5942(8) 0.3176(3) 1.4139(4)C (5) 0.5325(6) 0.2837(3) 1.3261 (4)C(6) 0.3535(7) 0.2713(3) 1.J288(4)C(7) 0.2983(7) 0.2478(3) 1.2324(4)C(8) 0.3781(6) 0.1878(2) 1.2032(4)C(9) o. 5650( 6) 0.1956 (2) 1.2103(4)C(10) 0.6302(7) 0.2251(2) 1.3048(4)C( 11) 0.6399(6) 0.1348(2) 1.1835(4)C(12) 0.5969(6) 0.1183(2) 1.0821(4)C(13) 0.4182(6) 0.1118(2) 1.0707(4)C(14) o. 3334( 6) 0.1712(2) 1.0974(4)C (15) 0.1501(6) 0.1615(2) 1.0869(4)C(16) 0.0976(7) 0.1366(2) 0.9906(4)C(17) o. 1842( 6) 0.0768(2) 0.9710(4)C(18) 0.3642(8) 0.0899(2) 0.9725(4)C(19) 0.4412(7) 0.0338(2) 0.9292(4)C(20) 0.5962(7) 0.0426(2) 0.8756(4)C(21) 0.308E!(7) 0.0084(3) o. 8617( 4)C(22) 0.1650(7) 0.0495 (3) 0.8713(4)C(23) 0.4962(9) 0.3726(3) 1.4383(5)C(25) 0.6307(7) 0.18.12(2) 1.3899(4)C(26) 0.3150(7) 0.1391(2) 1.2716(4)C(27) 0.3785(7) 0.2223(2) 1.0272(4)C(28) 0.1326 (8) 0.0289(3) 1.0398( 5)C(29) 0.6393(7) 0.0958(3) 0.8328(4)C(30) 0.6930(8) -0.0102(4) 0.8672(5)C(31 ) -o. 0915( 9) -0.0210(3) 1.1052(5)0(3) 0.7806(5) 0.J802( 2) 1.3250(3)O (11) 0.8126(4) 0.1363(2) 1.1886(3)O (281 ) 0.2161(4) -0.0060(2) 1.0815(3)0(282) -0.0265(5) 0.0278(2) 1.0494(3)430 L. KUTSCHABSKY ET AL.TABLE IIBond Distances (A) with e.s.d.'s in ParenthesesC(1)-C(2) 1.528(8) C(12)-C(1j) 1.523(7)C(1 )-C( 10) 1.567(8) C(13)-C(14) 1.554(6)C(2)-C(3) 1.521(9) C( 13)-C( 18) 1.537(7)C(3)-C(4) 1.555(8) C(14)-C(15) 1.569(7)C(3)-0(3) 1.426(7) C(14)-C(27) 1.557(7)C(4)-C(5) 1.541(8) .C(15)-C(16) 1.532(7)C(4)-C(23) 1.521(9) C(16)-C(17) 1.548(6)C(5)-C(6) 1.536(7) C(17)-C(18) 1.546(8)C(5)'7"C(10) 1.576(7) C( 17 )-C( 22) 1.541 (7)C(6)-C(7) 1.529(8) C(17)-C( 28) 1.508(8)C(7)-C(8) 1.556(7) C(18)-C(19) 1.539(7)C(8)-C(9) 1.589(7) C(19)-C( 20) 1.523(8)C(8)-C(14) 1.582(7) C(19)-C(21} 1. 573 (8~C(8)-C( 26) 1.550(7) C(20)-C(29) 1.381 (8)C( 9)-C( 10) 1.584(7) C(20)-C(30) 1.438(9)C(9)-C(11) 1.544(6) C(21)-C( 22) 1.528(8)C(10)-C(25) 1.549(7) C(28)-0(281 ) 1.203(7)C( 11)-C( 12) 1.520(7) C(28)-0(282) 1.350(7 )C(11)-0(11) 1.459(6) C(31)-O( 282) 1.452(8)17~-envelope conformation. The asymmetrie parameter? is I'lCP = 1.80• The confor-mational parameters" are summarized in Table V. Bond distances and bond anglesare close to the expected values. The H atom of the 3a.-hydroxyl group is involvedin an intermolecular hydrogen bond with 0(3) ... 0(281')= 2.863(7)A (symmetry code(i) l-x, 1I2+y, 5/2-z) connecting the molecules in b-direction. The molecular pac-king is given in Figure 2.The above mentioned data confirm unequivocaUy the structure of 2 and, there-fore, the native triterpenoid acid as 24-nor-3a., 11a.-dihydroxy-lup-20(29)-en-28-oicacid (1). With such a structure, compound 1 represents the final stage of the bio-synthetic demethylation pathway of 4,4-dimethylated lupanes to 24-nor compoundsin Acanthopanax triroliatus'.TRITERPENESTABLE IIIBond Angles (0) with e.s.d.'s in ParenthesesC(10)-C( 1)-C( 2)C(3)-C(2)-C(1 )C(4)-C(3)-0(2)0(3)-C(3)-C( 2)0(3)-C(3)-C(4)C(5)-C(4)-C(3)C(23)-C(4)-C()C(2)-C(4)-0(5)0(6)-C(5)-0(4)C(10)-C( 5)-C(4)0(10)-0(5)-0(6)C(7)-C(6)-0( 5)C(8)-C(7)-C(6)0(9)-C(8)-C(7)0(14)-C(8)-C(7)C(26)-C(8)-C(7)C(14)-C(8)-0(9)C(26)-O( 8)-C(9)0(26)-C(8)-C(14)0(10)-C(9)-0(8)C(11)-C(9)-0(8)0(11)-0(9)-0(10)C(5)-C(10)-0(1)C(9)-0(10)-C(1)0(25)-0(10)-C(1)0(9)-C( 10)-C( 5)or 25)-C( 1O)-O( 5)C(25)-C(10)-C(9)C(12)-C(11)-C(9)0(11)-0(11)-0(9)0(11)-0(11 )-0(12)0(1)-C(12)-0(11)113.7(5)112.7(5)110.9(5)109.2(5)110.4(4)i110.0(5)109.3(6)113.3(5)113.6(5)112.6( 5)111.6(5)109.8(4)113.6(5)108.6(4)110.4(4)106.9(4)108.8(4)112.2(4)109.9(4)116.)(4)107.1(4)115.4(4)104.7(4)109.6(4)108.0(4)108.9(4)112.4(4)112.8(5)110.2(4)112.1(4)106.8(4)111.0(4)0(14)-C(13)-C(12)C(18)-0(1)-0(12)0(18)-C(13)-C(14)0(13)-C(14)~C(8)C(15)-0(14)-C(8)C(27)-C(14)-C(8)C(15)-C(14)-0(13)C(27)-C(14)-C(13)0(27)-0(14)-C(15)0(16)-0(15)-C(14)C(17)-C(16)-C(15)C(18)-C(17)-C(16)0(22)-0(17)-C(16)C(28)-C(17)-C(16)0(22)-C(17)-C(18)C(28)-C(17)-C(18)C(28)-C(17)-0(22)0(17)-C(18)-0(13)C(19)-C(18)-0(13)C(19)-C(18)-C(17)C(20)-0(19)-C(18)C(21)-C(19)-C(18)C(21)-0(19)-C(20)0(29)-0(20)-0(19)C(30)-C(20)-0(19)0(30)-C(20)-0(29)C(22)-C(21)-C(19)C(21)-0(22)-C(17)0(281)-C(28)-0(17)0(282)-0(28)-0(17)0(282)-0(28)-0(281)C(31)-0(282)-C(28)431110.4(4)114.8(4)110.7(4)108.6(4)110.9(4)111.6(4)108.2(4)111.1(4)106.A(4)114.7(4)109.5(4)107.3(4)117.1(4)111.2(5)101.0(4)114.1(4)105.9(5)111.3(4)119.5(4)104.8(4)117.0(5)103.6(4)110.8(5)123.6(5)115.0(5)121.3(7)107.1( 5)103.6(4)127.2(7)111.4(5)121.3(6)116.4(5)432 L. KUTSCHABSKY ET AL.TABLE IVEndocyclic Torsion Angles ej with e.s.d.'s in ParenthesesC(10)-C(1)-C(2)-C(3)C(1)-C(2)-C(3)-C(4)C(2)-C(3)-C(4)-C(5)C(3)-C(4)-C(5)-C(10)C(4)-C(5)-C(JO)-C(1)C(5)-C(10)-C(1)-C(2)C(10)-C(5)-C(6)-C(7)C(5)-C(6)-C(7)-C(8)C(6)-C(7)-C(8)-C(9)C(7)-C(8)-C(9)-C(10)C(8)-C(9)-C(10)-C(5}C(9)-C(10)-C(5)-C(6)C(14)-C(8)-C(9)-C(11)C(8)-C(9)-C(11)-C(12)C(9)-C()1)-C(12)-C(13)C(11)-C(12)-C(13)-C(14)C(12)-C(13)-C(14)-C(8)C(13)-C(14)-C(8)-C(9)C(18)-C(13)-C(14)-C(15)C(13)-C(14)-C(15)-C(16)C(14)-C(15)-C(16)-C(11)C(15)-C(16)-C(17)-C(18)C(16)-C(17)-C(18)-C(13)C(17)-C(18)-C(13)-C(14)C(22)-C(17)~C(18)-C(19)C(17)-C(18)-C(19)-C(21)C(18)-C(19)-C(21)-C(22)C(19)-C(21)-C(22)-C(17)C(21)-C(22)-0(17)-C(18)-56.3(9)52.5(9)-54.2(9)60.3(8)-59.4(8)56.8(7)-61.3(7)61.4(8)-53.0(7)47.7(8)-48.7(8)54.2(8)-61.4(6)61.7(5)-61.4(6)59.0(6)-58.1(5)59.8(7)53.2(7)-52.8(7)56.8(7)-59.0(6)63.0(6)-61.5(7)-43.4(9)27.6(5)-1.2(5)-25.5(7)41.9(8)TABLE VPuckering Parameters for RingsRing Q(A) 0(°) e (0)A 0.59 215 174(1-2-3-4-5-10)B 0.57 130 172(5-6-7-8-9'-':10)C 0.64 37 4(8-9-11-12-13-14)D 0.60 93 6(13-14-15-16-17-18)E 0.44 2(17-18--19-21-22)TRITERPENES433434 L. KUTSCHABSKY ET AL.REFERENCES1. M. L i seh e w s k i, Ph. D. T y, L. K u t seh a b sky, D. P i e i i i e r, H. V.P h i e t, A. Pre i s s, T. V. S u n g, and G. Ada m, Phytochemistry 24 (1985)2355.2. Ph. D. Ty, M. Lischewski, H. V. Phiet, A. Preiss, T. V. Sung, J.Seh m i d t, and G. Ada m, Phytochemistry 23 (1984) 2889.3. Ph. D. Ty, M. Lischewski, H. V. Phiet, A. Preiss, Ph. V. Nguyen,and G. Ada m, Phytochemistry 24 (1985) 867.4. Li 1y M. Per r y, MedicinaL PLants of East and Southeast Asia, MIT PressCambridge 1980 p. 40.5. P. Main, S. E. Hull, L. Lessinger, G. Germain, J. P. Declercq,and M. M. W o o 1 i s o n, Multan 78. A System of Computer Programs for theAutomatic SoLution of CrystaL Structure from X-ray Diffraction Data, Univ. oiYork, England 1978.6. G. M. S h e 1d ric k SHELX 76. Program for CrystaL Structure Determination.Univ. oi Cambridge, England 1976.7. W. L. Du a x and D. A. N ort o n, Atlas of Steroid Structure, London, PlenumPress, London 1975.8. C. C rem e r and J. A. P o P 1e, J. Amer. Chem. Soc. 97 (1975) 1354.SAŽETAKMolekulska i kristalna struktura nove 24-triterpenoid-karbonske kiseline izolirane i:..Acanthopanax TrifoLiatusLeo Kutschabsky, Doris Pfeiffer, Manfred Li.schewski, Pham Dinh Ty i Gii.nter AdamOdređena je kristalna i molekulska struktura metil-estera 24-nor-3a l l u-dihi-dro-lup-20(29)-en-28 karbonske kiseline. Supstanca kristalizira u ortorompskomsustavu, prostorna grupa P212121,parametri jedinične ćelije: a = 8.437(4), b = 22.340(8),c = 14.096(5), A, Z = 4, De = 1.179 g cm-lo

Molecular and Crystal Structure of a New 24-nor-Triterpenoid Carboxylic Acid from Acanthopanax Trifoliatus

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