| 摘要 |
In producing N-alkylated amino acid esters of formula (I) by the reaction of alpha-amino acid esters with an alpha-substd. carboxylic acid ester having a leaving gp. at the alpha-position in the presence of a base, the alpha-substd. carboxylic acid ester is used in an amt. excess to the alpha-amino acid ester and the reaction is carried out without using solvent. In (I) R1 and R4 are alkyl, aralkyl, cycloalkyl, or aryl; R2 and R3 are alkyl, aralkyl, aryl, heterocyclealkyl, aminoalkyl, or guanidylalkyl; asterisk indicates an asymmetric carbon. Specifically, the reaction is carried out in the presence of a base, e.g. Et3N, Oct3N, pyridine, N,N-dimethylaminopyridine, diazabicycloundecene, carbonate or bicarbonate of Na, K, Li or Mg, in an inert cpd., e.g. MeCN, EtCN, DMFA, DMSO, HMPA, CH2Cl2, CHCl3, CCl4, benzene, toluene, xylene, hexane, heptane, cyclohexane, 20-120 deg. C for 1-30 hrs.
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