• YAKHAK HOEJI
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• v.47 no.3
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• pp.130-134
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• 2003

For the development of new synthetic method for unnatural amino acid esters, N-aryl phenylglycine Ο-alkyl esters 4a∼i were synthesized through base-catalyzed hydrolysis of 1,5-diphenylhydantoins 1a∼b and Ο-alkylation in 16∼87％ yield. An efficient and practical route for final 4a∼i was that the starting materials 1a∼b were heated in dil-methanol for 30 minute using sodium hydroxide or potassium hydroxide and evaporated. In addition, reaction mixture were refluxed for 1 h in DMF. All synthetic process from hydantoin to N-aryl phenylglycine Ο-alkyl esters 4a∼i could be carried out in one-pot without isolation of intermediates.

• YAKHAK HOEJI
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• v.47 no.5
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• pp.276-282
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• 2003

For the development of new synthetic method for unnatural amino acid esters, N-aryl phenylglycine Ο-alkyl esters 4a∼i were synthesized through esterification, bromination, C-N bond formation from commercially available phenylacetic acids. An efficient and practical reaction condition for esters 2a∼c was that the starting materials 1a∼c were refluxed in absolute methanol for 3 hours with catalytic concentrated hydrosulfuric acid. In addition, bromines 3a∼c were formated for 3h in dichloromethane at rt with N-bromosuccinimide. Bromines 3a∼c were also converted to 4a∼i through substitution of arylamines during refluxing for 24 hours in ethanol with triethylamine. Interestingly, ethyl esters 5a∼c were formed via transesterification reaction when the p-sulfamylanilino group was used as a nucleophile in ethanol solvent.