20233-47-0Relevant articles and documents
Studies of the synthesis of biomarkers. XI. Synthesis of 4,5-secocholestane and 4-methyl-4,5-secocholestane
Ma, Jian-Guo,Li, Tong-Shuang,Li, Yu-Lin
, p. 551 - 553 (2007/10/02)
4,5-Secocholestane (1a) and 4-methyl-4,5-secocholestane (1b) were synthesized from cholesterol (2) in five and seven steps, respectively. The key intermediate, 5-oxo-4,5-secocholestan-4-al (7) was reduced by the Clemmensen method to afford 1a. Meanwhile, 7 underwent selective Wittig reaction, Clemmensen reduction, and hydrogenation to give another target molecule, 1b. The structure of an unknown biomarker was shown to be different from the proposed la by gas Chromatographic and mass spectrometric comparison.
Steroidal N-Nitroamines. Part 3. Pyrolytic Denitroamination of N-Nitroamino-adamantane and -bornane, and of Several Steroidal N-Nitroamines
Francisco, Cosme G.,Freire, Raimundo,Hernandez, Rosendo,Melian, Daniel,Salazar, Jose A.,Suarez, Ernesto
, p. 2325 - 2328 (2007/10/02)
The thermal decomposition of several nitroamines has been investigated.The axial nitroamines 6β-nitroamino-5α-cholestan-3β-yl acetate (1) and 23R-nitroamino-(20S,22S,25S)-5β-spirostan-3β-yl acetate (8) gave exclusively nitrogen-free olefins.The trans-diaxial α-hydroxy nitroamines (2) and (3) afforded the 5α- and 4α-oxirane (6) and (7), and small amounts of the corresponding trans-diols (4) and (5).The 7β- and 7α-nitroaminocholest-5-en-3β-yl acetate (10) and (11) gave 7-oxocholesteryl acetate (14) and a mixture of the 7β- and 7α-alcohol (12) and (13) with 50 and 33percent inversion of configuration, respectively.The oxidation product adamantanone (16) was produced together with adamantan-2-ol (20) in the pyrolysis of 2-nitroaminoadamantane (19).Carbon-carbon rearrangement was observed in the case of exo-2-nitroaminobornane (22) and 20β-nitroaminopregn-5-en-3β-yl acetate (25).The nitroamine (25) yielded the 3-O-acetyl derivatives of pregna-5,20-dien-3β-ol, (29), pregna-5,17(20)(E)-dien-3β-ol, (30), 3β-hydroxypregn-5-en-20-one, (28), 17α-methyl-D-homoandrost-5-ene-3β,17aβ-diol, (31), and a mixture of pregn-5-ene-3β,20-diols (26) and (27).Camphene (23) and tricyclene (24) was obtained from exo-2-nitroaminobornane (22).Mechanisms for the formation of these products are discussed.