Title: Nimbiol
CAS Registry Number: 561-95-5
CAS Name: (4aS-trans)-2,3,4,4a,10,10a-Hexahydro-6-hydroxy-1,1,4a,7-tetramethyl-9(1H)-phenanthrenone
Additional Names: 6-hydroxy-7-methyl-9-oxopodocarpane
Molecular Formula: C18H24O2
Molecular Weight: 272.38
Percent Composition: C 79.37%, H 8.88%, O 11.75%
Literature References: (+)-Form found in the bark of the neem tree, Azadirachta indica A. Juss. (Melia azadirachta L.), Meliaceae: P. Sengupta et al., Chem. Ind. (London) 1958, 861. Structure: P. Sengupta et al., Tetrahedron 10, 45 (1960). Also obtained by conversion of podocarpic acid: Bible, ibid. 11, 22 (1960); Wenkert et al., J. Am. Chem. Soc. 83, 2320 (1961). Total synthesis of (±)-form: W. L. Meyer et al., J. Org. Chem. 40, 3686 (1975). Synthesis of (±)-methyl ether: Ramachandran, Dutta, J. Chem. Soc. 1960, 4766; Delobelle, Fétizon, Bull. Soc. Chim. Fr. 1961, 1900; Nasipuri, Roy, J. Indian Chem. Soc. 40, 327 (1963).
Properties: Crystals from dilute methanol or platelets by high vac sublimation. mp 248-252°. [a]D25 +33° (chloroform). uv max (abs alcohol): 234, 283 nm (log e 4.13, 4.10).
Melting point: mp 248-252°
Optical Rotation: [a]D25 +33° (chloroform)
Absorption maximum: uv max (abs alcohol): 234, 283 nm (log e 4.13, 4.10)
Derivative Type: Methyl ether
Molecular Formula: C19H26O2
Molecular Weight: 286.41
Percent Composition: C 79.68%, H 9.15%, O 11.17%
Properties: Crystals, mp 143°. [a]D25 +43.7° (chloroform). uv max (alcohol): 207, 232, 279 nm (log e 4.18, 4.15, 4.12).
Melting point: mp 143°
Optical Rotation: [a]D25 +43.7° (chloroform)
Absorption maximum: uv max (alcohol): 207, 232, 279 nm (log e 4.18, 4.15, 4.12)
Derivative Type: (±)-Form
Properties: White needles from CH3OH, mp 237.0-237.5°.
Melting point: mp 237.0-237.5°
Derivative Type: (±)-Methyl ether
Molecular Formula: C19H26O2
Molecular Weight: 286.41
Percent Composition: C 79.68%, H 9.15%, O 11.17%
Properties: Crystals from hexane. mp 112-113°. uv max (alcohol): 207, 232, 279 nm (log e 4.13, 4.13, 4.11) (Delobelle, Fétizon). Also reported as needles from CH3OH, mp 117-118° (Nasipuri, Roy).
Melting point: mp 112-113°; mp 117-118° (Nasipuri, Roy)
Absorption maximum: uv max (alcohol): 207, 232, 279 nm (log e 4.13, 4.13, 4.11) (Delobelle, Fétizon)
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