N-bromobutanimide → HCID 54221950, compound

Participants

Reaction Steps

Benzyl 2-oxo-7-phthalimidoheptanoate (prepared by alkylation of benzyl 1,3-dithiane-2-carboxylate with 5-phthalimidopentyl bromide and subsequent oxidative conversion to the ketone with N-bromosuccinimide) is condensed with L-alanyl-L-proline in the presence of excess NaBH3CN. The condensation product, N-(1-benzyloxycarbonyl-6-phthalimidohexyl)-L-alanyl-L-proline, (390 mg.) in 25 ml of 50% aqueous ethanol is hydrogenated at 40 psi over 10% palladium on charcoal. Removal of solvent and catalyst yields N-(1-carboxy-6-phthalimidohexyl)-L-alanyl-L-proline (320 mg) having the expected spectral and chromatographic properties. A portion of the above intermediate (152 mg) in 2 ml of ethanol is refluxed with hydrazine (32 mg) for 1.5 hours. The phthalhydrazide is removed by filtration; the ethanol is removed under vacuum and the residue is absorbed on strong acid ion-exchange resin. Elution with 2% aqueous pyridine and freeze-drying gives the desired N-(1-carboxy-6-aminohexyl)-L-alanyl-L-proline (58 mg.). The spectral data are consistent with structure. The mass spectrum shows a peak at 311 for the molecular ion minus water (329-18).

Provenance & Evidence