2-Mercaptoethanols, acylation

The achiral dicarbonyl complex 1 has been shown to undergo facile 1,4-addition of amines and thiols to generate the elaborated acyl complexes 2. The more nucleophilic sulfur atom of 2-mercaptoethanol selectively adds to such complexes45. 

Other authors have described the lipase-catalyzed chemoselective acylation of alcohols in the presence of phenolic moities [14], the protease-catalyzed acylation of the 17-amino moiety of an estradiol derivative [15], the chemoselectivity in the aminolysis reaction of methyl acrylate (amide formation vs the favored Michael addition) catalyzed by Candida antarctica lipase (Novozym 435) [16], and the lipase preference for the O-esterification in the presence of thiol moieties, as, for instance, in 2-mercaptoethanol and dithiotreitol [17]. This last finding was recently exploited for the synthesis of thiol end-functionalized polyesters by enzymatic polymerization of e-caprolactone initiated by 2-mercaptoethanol (Figure 6.2)... 

Acyl-coenzyme A Synthase (from yeast) [9012-31-1] Mr 151,000, [EC 6.2.1.1]. This enzyme has been purified by extraction into phosphate buffer pH 6.8-7.0 containing 2-mercaptoethanol and... 

Reaction with tPiVA. The above conditions were modified to keep both APA-Br and tRNA in solution by replacing the 60% MeOH with 90% DMSO, 10 mM KPO4 (pH 7.4). Under these conditions, at least 20 txM tRNA was soluble and the reaction with 500 juM APA-Br or PA-Br was complete in less than 10 min at room temperature. Mercaptoethanol was added to consume the excess acyl bromide and the tRNA was dialyzed against water to remove most of the DMSO before... 

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