Vol. 45, No. 3, pp. 533-535. 1997 ~3 1997 Elsevier Saence Ltd All rights reserved. Printed in Great Bntain 0031-9422/97 $17.OfJ+O 00 Phgrochemrrrry, PII: SOO31-9422(%)00840-O CARVOTACETONE DERIVATIVES SPHAERANTHUS FROM THE EGYPTIAN SUAVEOLENS zyxwvutsrqpo PLANT AHMEDA. AHMED and AHMED A. MAHMOUD Chemistry Department, Faculty of Science, El-Minia University, El-Minia-61519, Egypt zyxwvutsrqponmlkjihg (Received in revised form 4 November 1996) Key Word Index--Sphaeranthus suaveolens; Asteraceae; monoterpenes; carvotacetone deriva- tives. Abstract-Extraction of the aerial parts of Sphaeranthus suaveolens afforded three new carvotacetone derivatives, together with four known compounds. The structures were elucidated by spectroscopic analysis. 0 1997 Elsevier Science Ltd. All rights reserved INTRODUCTION The genus Sphaeranthus (tribe Inuleae, family Asteraceae) is distributed mainly in the tropical and subtropical areas of Africa, Asia and Australia. Few of its 40 or so species have been chemically studied. The main compounds reported so far are thiophenaecetylenes, inositol esters, sesquiterpene lactones and carvotacetone derivatives [l-6]. The importance of this genus stems from the wide use of its members in folk medicine in the treatment of skin infections, glandular swellings, bronchitis, jaundice and nervous depression [6, 71. We have studied an Egyptian collection of Sphaeranthus suaveolens D. C. R’ RESULTS AND DISCUSSION The aerial parts of Sphaeranthus suaveolens afforded, in addition to 4-[5-( 1,3-pentadinynyl)-2-thienyl]-3-butyne-1,2-diol [8], thymohydrochinone-2-0P-glucopyranoside [l], five carvotacetone derivatives 1, 2 [l], 3 [l, 2, 91 4 and 5. The main constituent was the carvotacetone 3. The ‘H and 13CNMR spectral data of 1 (Tables 1 and 2) showed the presence of a carvotacetone derivative with an acetoxy group. The ‘H NMR spectral data were similar to those of 3b,%,7-trihydroxycarvotacetone isolated previously from S. bullutus [l]. However, H-3 was shifted more downfield (6 5.60) in 1, and together with a new methyl signal characteristic for an acetate group (6 2.09) led to the 3-0-acetyl derivative of the trihydroxycarvotacetone [l]. The stereochemistry of 1 was deduced from the coupling constants. The molecular formula of 4 was established by high R2 X =o 1 AC H 2 3 4 5 H Tig (2-OH-Et) Acr Tig Tig AC AC AC =o =o =o o?-oTig, H resolution FAB-mass spectrometry which revealed a molecular ion peak at m/z 341.3721; calculated for C,,HZ507 [M+H]+, 341.3775. The ‘H and 13CNMR spectra of compound 4 (Tables 1 and 2) were in part very similar to those of the corresponding main compound Su-acetoxy-3/?-tigloyloxy-7-hydroxycarvotacetone (3) [ 1, 2, 81. The spectra indicated by typical signals that the tiglate residue was replaced by a (2cr-hydroxyethyl)acrylate group. The molecular formula of 5 was found to be CZzH3,0, by high-resolution FAB-mass spectrometry (W+Hl+, m/z = 409). The loss of a molecule of acetic acid led to peak at m/z 349 (100%). The presence 533 A.A. 534 Table 1. ‘H NMR spectral OCOR’ MAHMOUD data of compounds 1,4 and 5 (400 MHz, CDCI,, &values) zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJ Multiplicity 1 4 5 6.96 5.60 d 2.07 4.56 - 6.99 5.67 d 2.47 5.89 - 4.35 br s 4.33 4.28 2.04 1.03 0.99 6.29 5.91 4.71 1.44 2.12 6.07 dt 5.50 dd ddd 2.32 d 4.56 d 5.74 4.08 dt 4.04 2.04 dw d 1.oo d 0.94 6.80 br q (2H) brs (6H) 1.81 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPO 1.77 br s (6H) zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQP 2.18 1.10 1.08 2.09 s 8 9 10 OCOR’ andA.A. AHMED - dt br s br d dq d s 2.05 J[Hz]: 2,3 = 7; 2,7 = 2,7’ = 1; 3,4 = 3.5; 4,5 = 12; 4,8 = 4; 8,9 = 8,10 = 7; (compound 5: 5,6 = 3.5); OTig: 3,4 = 7, (2-OH-Et)Acr: 3,4 = 1; 4,5 = 6.5. Table 2. “C NMR spectral 1 and S5 (100 MHz CDCI,, &values) data of compounds C 1 3 4+ 5*tS Multiplicity§ 1 2 3 4 5 6 7 8 9 10 OR’ 138.14 139.39 71.72 48.75 67.44 201.62 (s) 60.33 27.81 19.73 19.73 AC 139.29 138.81 67.53 46.22 73.06 195.46 (s) 60.62 27.80 19.70 19.64 Tig 139.65 124.59 69.20 40.19 68.87 65.87 (d) 63.02 26.68 20.11 19.98 Tig S C-l’ c-2 C-3’ c-4 C-5’ OR’ C-l” C-2” 170.09 21.06 (q) 167.05 127.97 (s) 138.20 (d) 12.16 (q) 14.54 AC 170.08 21.07 139.62 138.56 67.41 46.82 73.84 194.95 60.46 27.83 19.67 19.60 (2-OHEt)Acr 165.76 143.41 124.79 66.55 21.45 AC 169.96 21.04 166.98 128.32 (s) 138.20 (d) 11.92 (q) 14.45 AC 170.42 21.30 S - H - - (S) (S) (r) (d) d d d d t d 4 4 4 S 4 * 13C assignment based on HMQC experiments. 7 Assignment based on COLOC experiments $6-OTig: 167.88, 128.21, 12.10, 14.42. 5 Multiplicity was determined using DEPT experiments. of two tigloyloxy groups was deduced from the two fragments at m/z 249 [349 - CSH802 + HI+ (20%) and 149 [249-CSHs02+ H]+ (90%). The ‘H NMR spectrum of 5 (Table 1) revealed the presence of an acetate (S 2.05, 3H, s) and two tiglates (6 6.80, 2H, qq; 1.81, 6H, br s and 1.77, 6H, br s). Comparison of the IR and 13C NMR spectral data with those of 3 showed the absence of the a&unsaturated ketone. Instead, an additional carbon signal was observed in the oxygenated area of 6 65.87 (4. A new proton signal appeared at 6 5.74 (IH, d, J = 3.5 Hz) and showed a coupling with H-5 (6 4.56, IH, dd, J = 12, 3.5 Hz). Furthermore, the olefinic proton signal, H-2, was shifted upfield at 6 6.07 due to the absence of the keto group at C-6. The ‘H-‘H COSY spectrum allowed the assignment of all proton signals while the 13CNMR 535 Carvotacetone derivatives (5), 225 [M-R’CO,H+H]+ (57), 185 (loo), 165 (53) signals were assigned by HMQC and DEPT experi149 (35), 123 (54);); [a]u-117(CHCl,; c 1.1681). ments. The relative positions of the ester groups was 3B,6a-Ditigloyloxy-5a,7-dihydroxy-8,9-dihydrolimo finally proved by COLOC experiments, which showed nene (5). Oil; IR I$~~‘~,cm-‘: 3600 (OH), 1730 (OAc), connections between C-l of 3-OTig at 6 166.98, C-l 1720 (C=CCO,R); HRFAB-MS [M+H]+ 409.4448 of 6-OTig at 6 167.88 and C-l of S-OAc at 6 170.42 (calcd for CzzH3307: 409.4957); positive ion FAB-MS with H-3, H-6 and H-5 of the terpene part, respecm/z (rel. int.): 409 [M+H]+ (5), 349 [M -HOAc+ tively. The stereochemistry was confirmed by the H]+ (100) 309 [M -R’CO,H+H]+ (65) 259 coupling constants as well as a NOE between H-S and [349-C5H802+H]+, 149 [349_2(C,H,O,)+H]+ H-6. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (90) 137 (52), 121 (15); [a],,-274 (CHCl,; c 1.987). zyxwvutsrqpon EXPERIMENTAL REFERENCES 1. Jakupovic, J., Grenz, M., Bohlmann, F. and M aterial, extraction and isolation. S. suaveolens was collected from the River Nile Bank, El-Minia, Egypt, Mungai, G. M., Phytochemistry, 1990, 29, 1213. 2. Zdero, C., Bohlmann, F. and Mungai, G. M., in April 1990; voucher specimens are deposited in Phytochemistry, 1991,30, 3297. the Botany department, Faculty of Science, El-Minia 3. Sohoni, J. S., Rojatkar, S. R., Kulkarni, M. M., University. The aerial parts of the plant (2 kg) were Dhaneshwar, N. N., Ravale, S. S., Gururow, T. air-dried, ground and extracted with Et+petrolN. and Nagasampagi, B. A., Journal of the ChemMeOH (1: 1: 1) at room temp. The extract was sepistry Society, Perkin Transactions I, 1988, 157. arated as previously reported [lo] by CC (silica gel) M. G., Ananthasubramanian, L., eluted with petrol, Et,0 and MeOH with increasing 4. Gogte, Nargund, K. S. and Bhattacharyya, S. C., Indian polarity. The resultant frs were prefractionated by CC on Sephedex LH-20. The final separation and Journal of Chemistry, 1986, 25B, 233. purification were carried by TLC as well as in part by 5. Aboul-Ela, M. A., Seif El-Din, A. A. and Ahmed, HPLC (MeOH-H20). The known compounds were A. A., Alexandria Journal af Pharmaceutical Sciidentified by comparison of their ‘H,13C NMR, mass ence 1992,6(3), 269. spectra with those which have been reported in the 6. Shekhani, M. S., Shah, P. M., Yasmin, A., literature. Siddiqui, R., Preveen, S., Khan, K. M., Kazmi, S. U. and Atta-ur-Rahman, 3fi-Acetoxy-5a,7-dihydroxycarvotacetone zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (1). Gum; Phytochemistry, IR ~~~~3, cm-‘: 3610, 3500 (OH), 1735 (OAc), 1690 1990,29,2573. 7. Watt, J. M. and Breyer, M. G., ed. in The M ed(C=CC=Q); positive ion FAB-MS m/z (rel. int.): 243 icinal and Poisonous Plants of Southern and East(6), 225 [M+H,O+H]+ (8) 183 [M+H]+ ern Africa. Livingstone, Edinburgh, 1962, p. 292. [M-HOAc+H]+ (20) 165 [225-HOAc] (20) 154 8. Bohlmann, F., Burkhard, T. and Zdero, C., Nat(100) 136 (70), 123 (19); [a],,-229 (CHCl,; c 2.1594). 3/3-Acetoxy-5a-(2a-hydroxyethyl)acryloyloxy-7urally Occurring Acetylenes. Academic Press, hydroxycarvotacetone (4). Oil; IR I$$‘,, cm-‘: 3500 London, 1973, p. 351. (OH), 1735 (OAc), 1720 (C==CCOIR) 1690 9. Jakupovic, J., Eid, F., Bohlmann, F. and El(C==CC==O); HRFAB-MS [M + H]+ 341.3721 (calcd Dahmy, S., Phytochemistry, 1987,26, 1536. for C17H2507: 341.3775) positive ion FAB-MS m/z 10. Bohlmann, F., Zdero, C., King, R. M. and Robinson, H., Phytochemistry, 1984, 23, 1979. (rel. int.): 341 [M + H]+ (30) 281 [M - R’CO,H + H]+