42801-75-2Relevant academic research and scientific papers
Amino Acids, 12. - Syntheses of DL-Cysteines from Acrylic Acid Derivatives
Effenberger, Franz,Beisswenger, Thomas,Dannenhauer, Fritz
, p. 2209 - 2224 (2007/10/02)
The addition of sulfenyl chlorides 1 to 2-alkenoic acid esters 2 gives mixtures of 2(3)-chloro-3(2)-thioalkenoic acid esters 3/4, whereas the addition of thiols 7 to methyl 2-chloro-2-propenoate (6) results in the formation of methyl 2-chloro-3-thiopropanoates 3 only.The dependence of the isomerization of 3 to 4 on the reaction conditions was investigated; at higher temperatures the formation of 4 is especially favored.At temperatures below 55 deg C the 2-azido compounds 8 are obtained without isomerization from 3 by reaction with sodium azide in the presence of a PT catalyst.Cysteine derivatives 9 or 10, resp., are obtained by hydrogenation of 8 with H2S/pyridine/H2O or with H2/Re2S; the overall yields of 9 or 10, resp., starting from 6 are as high as 70percent.DL-Cysteine is obtained in good overall yields as hydrochloride hydrate 16 by HCl-catalyzed hydrolysis of the 2-thiazolines 15a*HCl and 15e, which are prepared by HCl-catalyzed addition of thioacetamide (11a) to α-chloroacrylic acid (12) or the amide 13 and consecutive ring closure.
Amino Acids, 2. N-Acetyl α,β-Didehydro α-Amino Acid Esters from α-Azidocarboxylic Acid Esters and Acetic Anhydride by Nitrogen Elimination with Rhenium Catalysts
Effenberger, Franz,Beisswenger, Thomas
, p. 1497 - 1512 (2007/10/02)
α-Azidocarboxylic acid esters 2 react with acetic anhydride in presence of catalytic amounts of rhenium heptasulfide and - if necessary - by addition of hydrochloric acid to give N-acetyl 3 or/and N,N-diacetyl-α,β-didehydro-α-amino acid esters 4 in very g
