On October 1, 2016, Tiwari, Vinay Shankar; Murugula, Raghavendra; Yadav, Shyam Raj; Haq, Wahajul published an article.Recommanded Product: 98946-18-0 The title of the article was Synthesis of 4-hydroxy-2-methylproline derivatives via pyrrolidine ring assembly: Chromatographic resolution and diastereoselective synthesis approaches. And the article contained the following:
4-Hydroxy-2-methylproline diastereomers are successfully prepared without the use of an external chiral auxiliary. Dihydroxylation of the key intermediate (I) (Z = benzyloxycarbonyl) resulted in lactone (II) as a mixture of diastereomers in good yield. Mesylation, hydrogenation and concomitant intramol. cyclization of II led to the formation of both (2R,4R)- and (2R,4S)-4-hydroxy-2-methylprolines as a mixture of diastereomers. Appropriate protection followed by chromatog. separation resulted in isolation of both cis- and trans-diastereomers in enantiomerically pure form and in equal quantity. In subsequent experiments, the synthesis of the more challenging diastereomers (2R,4R)- and (2S,4S)-4-hydroxy-2-methylproline was achieved by diastereoselective iodolactonization of (R)- or (S)-allylalanine obtained after hydrolysis of intermediate I, followed by pyrrolidine ring closer under mild alk. conditions. After selective protection and deprotection, Fmoc-(2R,4R)-α-Me-Hyp(tBu)-OH (III) (Fmoc = 9-fluorenylmethoxycarbonyl), a building block suitable for solid phase peptide synthesis was obtained. The experimental process involved the reaction of tert-Butyl trichloroacetimidate(cas: 98946-18-0).Recommanded Product: 98946-18-0
The Article related to hydroxymethylproline enantioselective and diastereoselective synthesis solvent effect, allylalanine ring opening diastereoselective iodo lactonization reaction mechanism hydrolysis, pyrrolidine ring assembly chromatog resolution and other aspects.Recommanded Product: 98946-18-0
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