6546. Nimbin

Nomenclature

CAS number: 5945-86-8
(4α,5α,6α,7α,15β,17α)-6-(Acetyloxy)-7,15:21,23-diepoxy-4,8-dimethyl-1-oxo-18,24-dinor-11,12-secochola-2,13,20,22-tetraene-4,11-dicarboxylic acid dimethyl ester; 5-(acetyloxy)-2-(3-furanyl)-3,3a,4a,5,5a,6,9,9a,10,10a-decahydro-6-(methoxycarbonyl)-1,6,9a,10a-tetramethyl-9-oxo-2H-cyclopenta[b]naphtho[2,3-d]furan-10-acetic acid.
C30H36O9; mol wt 540.60.
C 66.65%, H 6.71%, O 26.64%.

Description and references

Bitter principle from various parts of the neem tree, Azadirachta indica A. Juss. (Melia azadirachta L.), Meliaceae: Siddiqui, Curr. Sci. 11, 278 (1942). Structure: C. R. Narayanan et al., Chem. Ind. (London) 1964, 322; C. R. Narayanan, R. V. Pachapurkar, Tetrahedron Lett. 1965, 4333. Stereochemistry: eidem, J. Org. Chem. 31, 2691 (1966); Harris et al., Tetrahedron 24, 1517 (1968). Crystal structure of dihydronimbin: C. R. Narayanan et al., Acta Crystallogr. B36, 486 (1980).

Chemical structure

Properties

Crystals from methanol, mp 205°. [α]D24 +170° (abs ethanol). uv max (95% ethanol): 210, 330 nm (ε 32700; 66). Practically insol in water. Sol in ether, abs alcohol.

Derivative

Dihydronimbin.
C30H38O9; mol wt 542.62.
C 66.40%, H 7.06%, O 26.54%.

Properties

Crystals from methanol, mp 215-216°. [α]D +167.5° (chloroform). uv max (95% ethanol): 210, 298 nm (ε 16200; 29).