Stereoselective hydrolysis of nitriles and amides under mild conditions using a whole cell catalyst
摘要:
An immobilised whole cell Rhodococcus sp. (SP 361) has been shown to be an effective catalyst for the stereoselective hydrolysis of both racemic and prochiral nitrile containing compounds. 2-Alkyl-arylacetonitriles 6a-8a were hydrolysed to (S)-acids and (R)-amides whereas the closely related substrate 9a gave the (R)-acid. A series of prochiral dinitriles 10a-13a were hydrolysed to the corresponding (S)-acids with e.e.'s 22-84%. Models to account for the stereoselectivity of the enzymic hydrolyses have been proposed.
Stereoselective hydrolysis of nitriles and amides under mild conditions using a whole cell catalyst
摘要:
An immobilised whole cell Rhodococcus sp. (SP 361) has been shown to be an effective catalyst for the stereoselective hydrolysis of both racemic and prochiral nitrile containing compounds. 2-Alkyl-arylacetonitriles 6a-8a were hydrolysed to (S)-acids and (R)-amides whereas the closely related substrate 9a gave the (R)-acid. A series of prochiral dinitriles 10a-13a were hydrolysed to the corresponding (S)-acids with e.e.'s 22-84%. Models to account for the stereoselectivity of the enzymic hydrolyses have been proposed.
Palladium-catalyzed regiodivergent hydroaminocarbonylation of alkenes to primary amides with ammonium chloride
作者:Bao Gao、Guoying Zhang、Xibing Zhou、Hanmin Huang
DOI:10.1039/c7sc04054g
日期:——
the synthesis of primary amides has long been an elusive aim. Here, we report an efficient catalytic system which enables inexpensive NH4Cl to be utilized as a practical alternative to gaseous ammonia for the palladium-catalyzed alkene-hydroaminocarbonylation reaction. Through appropriate choice of the palladium precursors and ligands, either branched or linear primary amides can be obtained in good
was also eliminated by the addition of 2 equivalents of water to the reaction system. The reduction was applied to the syntheses of precursors of such anti-inflammatory agents as ibuprofen, butibufen, naproxen, and related compounds, as well as (±)-ar-turmerone, an odorous sesquiterpene.
A cobalt‐catalyzed 1,4‐aryl migration/disulfonylation cascade applied to α‐bromo N‐sulfonyl amides was developed. The reaction was highly chemoselective, allowing the preparation of α‐arylamides possessing a variety of functional groups. The method was used as the key step to synthesize an alkaloid, (±)‐deoxyeseroline. Mechanistic investigations suggest a radical process.
Arylethanolamine derivatives, their preparation and use in
申请人:Beecham Group p.l.c.
公开号:US04588749A1
公开(公告)日:1986-05-13
Compounds of formula (II): ##STR1## or a pharmaceutically acceptable salt thereof, in which X is an oxygen atom or a bond, R.sup.1 is a hydrogen, fluorine, chlorine or bromine atom or a trifluoromethyl or C.sub.1-4 alkyl group, each of R.sup.2 and R.sup.3 is a hydrogen atom or a C.sub.1-4 alkyl group, R.sup.4 is a C.sub.1-4 alkyl group, R.sup.5 is a hydrogen atom or a C.sub.1-4 alkyl group, and n is an integer of from 1 to 3; are useful as anti-obesity and/or anti-hyperglycaemic agents.