Calotropenyl acetate, a new pentacyclic triterpene of the ursane series isolated from the flowers of Calotropis procera, is assigned structure 1 on the basis of chemical and spectral studies.Calotropis procera R.Br. (Asclepiadaceae) grows widely in tropical regions of Asia and Africa. The milky juice of this plant is usecílby the natives of India as a purgative, while the flowers are considered digestive, stomachic, tonic, and useful in cough, asthma, catarrh, and loss of appetite. The root bark is said to promote secretions and to be useful in treating skin diseases, enlargement of the abdominal viscera, intestinal worms, ascites, and anasarca (1). A literature survey shows that only one terpenoidal constituent has so far been reported from this plant (2). A systematic study on the fresh and undried flowers has resulted in the isolation of a new pentacyclic triterpene that is provisionally named calotropenyl acetate. Its structure has been elucidated as urs-19(29)--3ß^1 acetate through chemical and spectroscopic studies. RESULTS AND DISCUSSIONCalotropenyl acetate [!}: mp 198°; {a}D +8.9°. The hrms gave a molecular ion peak at 468.7677 corresponding to the molecular formula C32H5202 (caled 468.7660). The ir spectrum (CHC13) showed an acetate group (1725 and 1320 cm-') and a methylene group (1640 and 880 cm-1). The 13C-nmr spectrum showed 32 carbon atoms; the multiplicities of these were determined by using DEPT experiments (3) which revealed the presence of 7-methyl, 11-methylene, and 6-methine carbons. The 'H-nmr (300 MHz) spectrum showed signals for vinylic protons (broad singlets at 4.6 and 4.68, 1H each), an equatorial acetoxy group (double doublet at 4.52, 1H, 3ct-H and singlet at 2.08, 3H, OCOCH3), one secondary methyl group (doublet at 0.91,J=6.5 Hz), and six tertiary methyls (singlets at 0.82, 0.83, 1.0, 1.01, 1.03).The mass spectrum of 1 is also characteristic of pentacyclic triterpenes of the Ursane series in which rings A, B, C, and D are saturated. The major ions a and b were generated by transfer of hydrogen from C-26 to C-l 1 accompanied by cleavage of 9-11 and 8-14 bonds with charge retention on either of the resulting fragments (4,5

A new ursene type triterpene, pakistanol [1], was isolated from Abutilón pakistanicum. Its structure has been assigned as urs-12(13)-en-24|i-ol on the basis of chemical and spectral studies. Taraxasterol, ß-sitosterol, and a-amytin were also isolated.

Euphorcinol, a new triterpene of the friedelane group, has been isolated from the fresh and un-dried stem bark of EUPHORBIA TIRUCALLI. The structure 1 is assigned to it on the basis of chemical and spectroscopic studies including 2D-NMR.

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