116819-84-2

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• 97691-82-2 3β-benzyloxy-5-hydroxy-5α-cholestan-6-one 

Relevant academic research and scientific papers

Photochemistry of cyclic α-hydroxy ketones. I. The nature and genesis of the photoproducts from steroidal 5-hydroxy 6-keto steroids and compounds

Photolyses of 5-hydroxy-5α- and 5β-cholestan-6-one and their 3β-acetoxy- and 3β-benzyloxy derivates in benzene or ethanol proceed stereospecifically with retention of configuration at C-5 to give the corresponding lactones, 6-oxa-B-homocholestan-7-ones.Photolyses of 3β-acetoxy-7α-deutero-5-hydroxy-5α- and 5β-cholestan-6-ones also proceed sterospecifically to give the corresponding 5-deutero lactones. 3β-Acetoxy-5-deuteroxy-5α- and 5β-cholestan-6-one give on irradiation 1:3 and 7:1 mixtures, respectively, of the corresponding 7aα- and 7aβ-deutero lactones.Irradiation of 3β-acetoxy-5-methoxy-5α-cholestan-6-one in ethanol leads to the stereoselective formation of ethyl 3β-acetoxy-5-methoxy-5,6-seco-5α-cholestan-6-oate, while that of 3β-acetoxy-5α-cholestan-6-one gives mainly photoreduction products.These observations are interpreted in terms of α-cleavage of the C-5 - C-6 bond of the ketols to give alkyl acyl diradicals that undergo hydrogen transfer to give hydroxy ketenes, which then form the lactones.It is proposed that retention of configuration at C-5 results from two major factors - the nonplanar geometry of the hydroxyalkyl radical center, and fast hydrogen transfer in the diradical, the latter resulting from restricted rotation about the C-9 - C-10 bond.The specific transfer of the 7α-deuterium atom in the 7α-deutero ketols is attributed to these factors and to the preferred direction of opening to the diradical on α-cleavage.The O-deuterium labelling results are interpreted in terms of product development control in the conversion of the hydroxy ketenes to the lactones and are in accord with restricted rotation about the C-9 - C-10 bond.The photolysis of 3β-acetoxy-5-amino-5α-cholestan-6-one proceeds stereoselectively to give the 5β-lactam analogue of the 5β-lactone formed from the analogous 5α-ketol.

REMOTE SUBSTITUENT EFFECT ON THE REGIOSELECTIVITY IN THE BAEYER-VILLIGER OXIDATION OF 5α-CHOLESTAN-6-ONE DERIVATIVES

The regioselectivity in the Baeyer-Villiger oxidation of 5α-cholestan-6-one derivatives was markedly affected by the substituents at C-1, 2 or 3 position which were located at γ or δ position from the reaction center C-6.