Eniricerche S.p.a.

Anic S.p.a.

Sandro Di Gioacchino

Luciano Re

Antonio Paolinelli

Ugo Romano

Giancarlo Fornasari

A new process of synthesis of optically active .alpha.-amino acids is described through nitrosation in a non-aqueous, aprotic system of the corresponding N-carbamyl derivatives followed by decomposition of the thus obtained N-nitroso derivatives in aqueous acidic medium. The process, which is of a general applicability, leads to a remarkable increase in the reaction yields, due to the suppression of the main side reaction leading to the corresponding .alpha.-hydroxy-acid. Some N-nitroso intermediates, which can be recovered from the process of the invention, are also described.

Method of preparation of optically active .alpha.-amino-acids

A new process of synthesis of optically active .alpha.-amino acids is described through nitrosation in a non-aqueous, aprotic system, of the corresponding N-carbamyl derivatives followed by decomposition of the thus obtained N-nitroso derivatives in aqueous acidic medium. The process, which is of a general applicability, leads to a remarkable increase in the reaction yields, due to the suppression of the main side reaction leading to the corresponding .alpha.-hydroxy-acid. Some N-nitroso intermediates, which can be recovered from the process of the invention, are also described.

Method of preparation of optically active alpha-amino-acids

A process for the preparation of aromatic urethans by reaction between aromatic amines and alkyl carbonates, said reaction being carried out in the presence of a catalyst composed of an alcoholate of an alkali metal or an alkaline earth metal. The reaction is caused to take place at a temperature which is variable from +50.degree. C. and +150.degree. C., in the liquid phase and with a molar ratio of the carbonate to the amine of from 10:1 to 1:10.

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