Chemical Constituents of Corchorus capsuJaris and C. olitorius (Jute Plant), III. Structure of Corosin
2014
Manzoor-i-Khuda, M. | Habermehl, Gerhard
Corosin (8; R = R¹ = H) has been reisolated through a modified procedure, as its acetate (8; R=H, R¹ = Ac), in an overall yield of 0.2% from jute roots.On pyrolysis in vacuo, corosin gave pyro corosin (1a; R¹ = OH, R²= COOH, R³ = R⁵ = H, R⁴ = R⁶ = Me), shown to have a 12:18 (17) di-ene formed by elimination of the 19-OH and the angular C-28 carboxyl in the molecule. On rearrangement with concentrated sulphuric acid in acetic acid, corosin acetate gave corosin anhydro lactone acetate (7; R¹ = Ac, R = H), having a 13(18) double bond and a lactone bridge between the 28-carboxyl and the 20-carbon atom. Corosin acetate ester (8; R = Me, R 1 = Ac), on treatment with sulphuric-acetic acid reagent, gave as the main product anhydro corosin acetate ester (7; R = Me, R¹= A c), with a 12:18(19)-diene. The structure of corosin is proposed to be urs-12-ene-2α, 3β, 19α-trihydroxy-24, 28-dioic acid (8; R = R¹= H).
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