A new triterpenic constituent from Andrachne cordifolia

The petrol (60-80°) extract of the whole plant (aerial parts and roots) of Andrachne cordifolia. Muel-Arg yielded a new pentacyclic triterpene, glut-5(10)-en-3~-ol.

In our previous communication 1 , we reported the isolation and characterization of two triterpenoid constituents from the petrol (60-80°) extract of Andrachne cordifolia. We now report the isolation and structure elucidation of a new triterpene from the same plant.
On oxidation with chromic acid, the parent triterpene yielded a ketone, C 3 oH 48 0, m.p. 250-253°; vmax (KBr) 1730, 1650 cm-1 which was found to be identical with glut-5(10)-en-3-one (3) 1 by direct comparison of physical and spectral data with the authentic sample (m.m.p., Co-936 IR and Co-TLC). This settles the nature of the skeleton as well as the location of hydroxyl function at C-3 position.
Conclusive evidence in favour of the equatorial disposition of C-3 hydroxyl was secured from the 1 H NMR spectrum of (90 MHz, CDC1 3 ) of the acetate (2)   The structure of the compound 1 also received support from 13 c NMR data as below, which are comparable to those compounds having similar skeleton 5

Experimental
All m.p. are uncorrected. The whole plant of Andrachne cordifolia was supplied by M/s. United Chemical and Allied Products, Kolkata, India.
Air dried powdered whole plant (1 kg) of A. cordijolia was extracted with petrol (60-80°) in a soxhlet apparatus for 56 h. The extract was concentrated under pressure and then subjected to CC on silica gel (60-120 mesh, 200 g). The petrol (60-80°) : bt:nzene (1 : 1) eluent yielded the compound 1 (0.5 g) m.p. 230-232°. IR 1 H NMR, 13 C NMR and ElMS are discribed in the text. It may be mentioned in this connection that the triterpene is expected to have property of curing eye-sore 6 . Acetylation oftriterpene 1: The triterpene (1, 0.05 g) was dissolved in 5 ml acetic anhydride and 2 ml pyridine. The reaction was allowed to stand for four days at room temperature. The reaction was then poured into ice cold water, extracted with ether and dried when an acetate (2),0.06 g, m.p 210-212° was obtained.
Jones oxidation oftriterpene 1 : The triterpene 1 (0.2 g) was dissolved in 30 ml acetic HOAc and to it a solution of chromic acid (0.5 g) in 15 ml glacial HOAc was added. The mixture was refluxed for 2 h at 50°, cooled, filtered and the filtrate was acidified with moderately cone. HCl in the cold. The ppt was dissolved in ether, dried and evaporated. The crude solid on chromatography over silica gel (60-120 mesh, 50 g) furnished glut-5(10)-en-3one (3,