Ammonia → {(S)-2-carbamoylmethyl-4-methylpentyl)carbamic acid methyl ester

Beteiligte Stoffe

Reaktionsschritte

A 2 l, four-necked flask, equipped with a mechanical stirrer, thermometer pocket and a liquid ammonia inlet, was charged with {(S)-4-methyl-2-[((S)-1-phenylethylcarbamoyl)-methyl]pentyl}carbamic acid methyl ester (26) (25 g, 0.078 mole), tetrahydrofuran (175 ml), and water (25 ml). The reaction mixture was cooled to −40° to −60° C. and liquid ammonia (1000 ml) was added followed by addition of small pieces of sodium metal (7.2 g). The resultant reaction mixture was stirred vigorously for 4-10 hours until the ammonia had evaporated. Water (100 ml) was added to the reaction mass under N2 atmosphere at 5°-10° C., followed by separating the phases. The organic layer was separated and dried over anhydrous sodium sulphate and the solvent was stripped off. The residue was crystallized from diisopropyl ether to get 10.2 g (60% yield) of {(S)-2-carbamoylmethyl-4-methylpentyl)carbamic acid methyl ester with purity of 73% as measured by HPLC.

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