1164-95-0Relevant articles and documents
Regioselective esterification of polyhydroxylated steroids by Candida antarctica lipase B
Bertinotti, Anna,Carrea, Giacomo,Ottolina, Gianluca,Riva, Sergio
, p. 13165 - 13172 (1994)
The regioselectivity of Candida antarctica lipase B towards the acetylation of polyhydroxylated steroids has been systematically investigated. The enzyme showed a marked preference for the alcoholic moieties on the A ring and: on the steroidal side chain, making it possible the selective acylation at the positions 3 or 21 of polyhydroxy steroids. Acylation with the synthetically useful esters chloroacetate and levulinate was also accomplished, whereas esterification with benzoate and pivaloate was unsuccessful.
Steroid compound 3-site hydroxyl configuration inversion method
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Paragraph 0025; 0028; 0029, (2018/12/14)
The invention discloses a steroid compound 3-site hydroxyl configuration inversion method. The method specifically comprises the following steps that (1) a steroid compound containing a 3-site hydroxyl reacts with an acyl chloride compound; (2) the product obtained in the step (1) and a substituting agent are subjected to SN2 nucleophilic substitution reaction under existing of a phase transfer catalyst; and (3) the product obtained in the step (2) is subjected to a hydrolysis reaction. Compared with a Mitsunobu method, the method does not need to use triphenylphosphine and azodiformate pricedhigher, and accordingly the production cost is greatly lowered; meanwhile, a p-nitrobenzoic acid derivative which seriously affects the water environment does not need to be used, and therefore the method is more environmentally friendly. The method adopts cesium acetate/18-crown ether-6 system to conduct 3-site hydroxyl configuration inversion, can remarkably reduce occurrence of side reactions,accordingly a higher reaction yield is obtained, and the method is finally applicable to industrialized production.
The iron(II) complex [Fe(CF3SO3)2(mcp)] as a convenient, readily available catalyst for the selective oxidation of methylenic sites in alkanes
Canta, Merce,Font, David,Gomez, Laura,Ribas, Xavi,Costas, Miquel
supporting information, p. 818 - 830 (2014/04/03)
The efficient and selective oxidation of secondary C-H sites of alkanes is achieved by using low catalyst loadings of a non-expensive, readily available iron catalyst [Fe(II)(CF3SO3)2(mcp)], {Fe-mcp, [mcp=N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)cyclohexane-trans-1,2-diamine]}, and hydrogen peroxide (H2O2) as oxidant, via a simple reaction protocol. Natural products are selectively oxidized and isolated in synthetically amenable yields. The easy access to large quantities of the catalyst and the simplicity of the C-H oxidation procedure make this system a particularly convenient tool to carry out alkane C-H oxidation reactions on the preparative scale, and in short reaction times.
A new and concise way to enamides by fluoroalkanosulfonyl fluoride mediated Beckmann rearrangement of α,β-unsaturated ketoximes
Yan, Zhaohua,Xu, Yun,Tian, Weisheng
supporting information, p. 7186 - 7189 (2015/02/02)
The reaction of α,β-unsaturated ketoximes with fluoroalkanosulfonyl fluorides in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) underwent the Beckmann rearrangement smoothly to afford the corresponding acid-sensitive enamides in moderate to excellent yields, which provides a new efficient method for the preparation of acid-sensitive enamides.
