Rani, Archana

Shukla, Y N

NOPR

Indian Journal of ChemistryVol. 36B, March 1997, pp. 299-300Disubstituted tetrahydrofuran and an esterfrom Argyreia speciosa:Archana Rani & Y N Shukla"Central Institute of Medicinal and Aromatic Plants,P.O. CIMAP, Lucknow 226 015, IndiaReceived 16 July 1996; revised and accepted 4 November 1996Two new compounds isolated 'from the roots ofArgyreia speciosa have been characterized as tetradec-anyl palmitate 1 and 5,8-oxidotetracosan-1O-one 2 byphysico-chemical evidence.A rgyreia speciosa (Convolvulaceae), commonlyknown as Elephant Creeper is a woody climberdistributed 1 throughout India upto an altitude of300 m. The seeds are rich source of ergoline al-kaloids while the roots are reported-? to be tonic,bitter, aphrodisiac, diuretic and used in rheumat-ism, gonorrhaea, chronic ulcer and diseases ofnervous system. Since no work has been reportedon roots a systematic investigation on the root ex-tract was initiated. The characterization of twoconstituents, tetradecanyl palmiate 1 and 5,8-oxi-dotetracosan-lO-one 2 is reported herein.Chromatography of the hexane fraction over si-lica gel yielded compounds 1 and 2. Compound 1[IR: 2920, 2850, 1450, 725, 720 (straight chain),1380 (CH3), 1736 and 1250 cm-·I (ester CO)]had-in its IH NMR spectrum two triplets (J=6Hz) at 02.24 and 4.0 for - COCH2 and- CH2 - 0 - CO - functions, respectively. Alka-line hydrolysis of 1 afforded palmitic acid (m.p.,IR, mass spectrum) and tetradecanol (IR, MS).This compound was therefore characterized astetradecanyl palmitate.The IR spectrum of compound 2 showed bandsfor CO (1740 cm-I), -C-O-C (1240 em ),and straight-chain functions. An [M]+ at mlz 366in its mass spectrum was in agreement with themolecular formula C24H4602' Prominent a-fissionions at rn/z 225, 197, 169 and 41 together withthe ,B-fission ions involving McLaferty rearrange-ment! at m/z 184 and 182 established the loca-tion of CO group at C-lO in the molecule. Thestrong ions at m/z 68 [C4H40]+ , 69 and 70[C4H60]+ were due to the presence of a tetrahyd-rofuran ring in the cornpoundv'. The location of+CIMAP Publication No. 96-28JNotem/z 184m/z 169m/z 141m/z 127m/309m/ z 182m/z 197m/z 225m/z 239Scheme I - Mass spectral fragmentation of2.the ring between C-4 and C-9 was evident fromthe ions at m/z 309, 57, 239 and 127 (Scheme I).The IH NMR spectrum of this compound wasalso consistent with its structure as 2 (see Experi-mental).Straight-chain epoxy, polyhydroxy and furanoidcompounds=? are known to occur widely in na-ture but disubstituted tetrahydrofuran with a COgroup in the chain are rare".ExperimentalSectionMelting points are uncorrected. The IR spectrawere recorded in KBr and the 80 MHz IH NMRspectra in CDCl3 with the TMS as internal stand-ard. TLC analyses were carried out on silica gelplates and the spots were visualized by exposureto 12vapours. The roots were collected from localarea and identified in our Botany Department,where a vouchee specimen is maintained.Isolation of compound 1. The air-dried andpowdered roots (1.6 kg) were extracted withMeOH (10x4.5 L), the combined extracts con-centrated to 500 mL and water (500 mL) wasadded to it. The aq. methanolic extract was thenfractionated successively with n-hexane (5 x 1 L),EtOAc (5 x 11) and n-BuOH (5 x 500 mL). Rem-oval of solvent from the hexane extract yielded aresidue (45 g), a portion of which (22 g) waschromatographed over silica gel (600 g). Elutionwas carried out with hexane, hexane-CjrL, C6~'C6H6-CHCI3, CHCl3 and CHCI3-MeOH. Frac-tions (100 mL each) were collected and moni-tored by TLC. The residue from hexane-Cgl-l,fractions yielded a solid, crystallized from CHCl3-300..INDIAN J. CHEM. SEC B, MARCH 1997MeOH (70 mg), m.p. 76°; IR: 2920, 2850, 1736,1450, 1380, 1250, 725, 720 em -1; 1H NMR:<50.88 (6H, t, J= 6 Hz, 2x terminal Me), 1.25[50H, brs, (CH2hs], 2.24 (2H, t, J= 6 Hz,-CH2-CO-), 4.0 (2H, t, J=6 Hz,-CH2-0-CO-); MS mJz (rel, int): 452 [M]+(C3Ji6002) (1), 256 (10), 255 (8), 241 (11), 239(15), 213 (16), 211 (18), 197 (20), 196 (15), 127(15), 113 (20), 99 (25), 85 (40), 71 (50), 57 (100),43 (70).Alkaline hydrolysis of 1. The ester 1 (60 mg)was refluxed with ethanolic KOH (5%, 20 mL, 5hr). The mixture was diluted with water (100 mL)and after work-up it yielded tetradecanol (IR, MS)and palmitic acid, m.p. 65° (IR, MS).Isolation of compound 2. The benzene frac-tions on concentration provided a residue whichwas crystallized from MeOH, (30 mg), m.p. 65°;IR: 2920, 2850, 1740, 1450, 1380, 1240, 725,715 cm-1; 1H NMR: <50.88 (6H, t, J=6 Hz, 2xterminal Me), 1.50 (2H, m, H2-4), 4.14 (2H, m,H-5, H-8), 1..95 (4H, m, H2-6, H2-7), 2.35 (2H, d,J= 7 Hz, H2-9), 2.24 (2H, t, J= 6 Hz, H2-11),1.25 (28H, brs, 14 x CH2); MS mJz (reI int}: 366[M]+ (C24H4602)(4), 323 (3), 309 (15), 239 (20),225 (10), 197 (100), 184 (25), 182 (10), 169 (21),141 (25), 127 (13), 70 (18), 69 (15), 68 (20), 57(20),43 (60).AcknowledgementThe authors are grateful to Dr Sushil Kumar,Director, CIMAP, Lucknow for his encourage-ments during the course of this work.References1 The Wealth of India-Raw Materials, (PID, NewDelhi), 198!, p. 418.2 Chopra R N, Nayar S L & Chopra I C, Glossary of IndianMedicinal Plants, (CSIR, New Delhi, 1956, p. 24.3 Budzikiewicz H, Djerassi G & Williams 0 H, Imerpretoiionof Mass·Spectra of Organic Compounds, (Holden-Day, SanFrancisco), 1965, p. 6.4 Bhakuni R S, Shukla Y N & Thakur R S, Phytochemistry,26,1987,2607.5 Tandon M, Shukla Y N & Thakur R S, Phytochemistry, 3J,1992,2525. '6 Gunstone F 0, in Comprehensive Organic Chemistry, Vol5, edited by E Haslam (Pergamon Press, Oxford), 1979,p.595.7 Devon T K & Scott A I, Handbook of Naturally OccurringCompounds, Vol. 1, (Academic Press, New York), 1975,p.498.8 Zeng L, Ye Q, Oberlies N H, Shi G, Gu Z-M, He K &Mcl.aughlin J L, Nat Prod Rep, 13, 1996, 275.

Disubstituted tetrahydrofuran and an ester from Argyreia speciosa

http://nopr.niscair.res.in/bitstream/123456789/57064/1/IJCB%2036B%283%29%20299-300.pdf

Disubstituted tetrahydrofuran and an ester from Argyreia speciosa

Abstract

Similar works

Full text

Available Versions

NOPR