benzyl N-(2-iodoethyl)carbamate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: S-Benzyloxycarbonylaminoethyl-L-cysteine is prepared from benzyloxycarbonyl-2-iodoethylamine and L-cysteine by the method of H. Lindley (Austral. J. Chem., 12, 296,1959). The α-amino group is protected with tert-butoxycarbonyl using di-tert-butyl dicarbonate. The resulting fully protected S-2-aminoethyl-L-cysteine is condensed with L-proline-tert-butyl ester in the presence of N,N'-dicyclohexylcarbodiimide. This intermediate is readily purified by medium pressure liquid chromatography on silica in ethyl acetate/hexane (1:1). This intermediate is readily purified by medium pressure liquid chromatography on silica in ethyl acetate/hexane (1:1)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 6.92 g of N-benzyloxycarbonyl-2-iodo-ethylamine, 4.00 g of 1-benzylpiperazine, 15.66 g of potassium carbonate and 40 ml of hexamethylphosphoramide (HMPA) was stirred at room temperature for overnight. Water was added to the reaction mixture, and the resulting mixture was extracted with diethyl ether. The extract was washed and dried, and the solvent was removed under reduced pressure. The residue was purified by silica gel column chromatography (solvent; chloroform:methanol=15:1) to give 5.63 g of N-benzyloxycarbonyl-2-(4-benzylpiperazin-1-yl)ethylamine (yield: 70%, oily product, IR: 3230, 2910, 1710 cm-). the resulting mixture was extracted with diethyl ether The extract was washed dried the solvent was removed under reduced pressure The residue was purified by silica gel column chromatography (solvent; chloroform:methanol=15:1)