Synthesis of biological markers in fossil fuels. 7. Selected diastereomers of 4.alpha.-methyl-5.alpha.-stigmastane and 5.alpha.-dinosterane

Autor:	Jan St. Pyrek, Robert M. Carlson, Ewa Kolaczkowska, J. Michael Moldowan, Frederick J. Fago, Ivan L. Stoilov, David S. Watt
Rok vydání:	1993
Předmět:	chemistry.chemical_classification Mesylate Stereochemistry medicine.medical_treatment Organic Chemistry Diastereomer Alpha (ethology) Alkylation Steroid chemistry.chemical_compound Hydrocarbon chemistry medicine Chemical reduction Aliphatic compound
Zdroj:	The Journal of Organic Chemistry. 58:3444-3454
ISSN:	1520-6904 0022-3263
DOI:	10.1021/jo00064a039
Popis:	Efficient routes for the preparation of selected C-23 and C-24 diastereomers of the C 30 biological markers 4α-methyl-5α-stigmastane (1) and 5α-dinosterane (2) involved the alkylation of 20-(iodomethyl)-4α-methyl-5α-pregnane with either saturated or α,β-unsaturated esters. The alkylation of (20S)-20-(iodomethyl)-4α-methyl-5α-pregnane with methyl (3R)-3-ethyl-4-methylpentanoate furnished methyl (20R,23ζ,24S)-4α-methyl-5α-stigmastane-23-carboxylate, and a subsequent decarbomethoxylation provided (20R,24R)-1. The alkylation of (20S)-20-(iodomethyl)-4α-methyl-5α-pregnane with methyl (3S)-3,4-dimethylpentanoate led to methyl (20R,23ζ,24R)-4α,24-dimethyl-5α-cholestane-23-carboxylate, and reduction of this mixture provided principally (20R,23S,24R)-5α-dinosteran-29-ol. The further reduction of the mesylate of this isomer secured (20R,23S,24R)-5α-dinosterane
Databáze:	OpenAIRE
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