1,8-Diazabicyclo(5.4.0)undec-7-ene → (S)-[2-(1-iminoethylamino)ethyl]-L-homocysteine

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Reaction Steps

To a solution of N-t-butoxycarbonyl cysteine t-butyl ester (prepared by reduction of N-t-butoxycarbonyl cystine t-butyl ester with dithiothreitol) (291 mg, 1 mmol) in dry toluene (20 ml) is added N-benzyloxycarbonyl ethanolamine tosylate (349 mg, 1 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (150 μL, 1 mmol) and the mixture stirred vigorously overnight at room temperature under nitrogen. The mixture is partitioned between 50 ml each of ethyl acetate and 1N aqueous HCl. A further organic extract is combined and these extracts washed with aqueous sodium bicarbonate, water and brine, then dried and evaporated. Purification by column chromatography affords the title compound.

Provenance & Evidence