Hydrochloric Acid → HCID 70475851, compound

Participants

Reaction Steps

To a solution of t-butyl 7-amino-3-methylceph-3-em-4-carboxylate (810 mg.) and 1-(2,2-diethoxyethyl)-3-(tetrahydropyran-2-yl)carbodiimide (726 mg.) in dry CH2Cl2 (8 ml.) under nitrogen at room temperature was dropwise added a 2N ether solution of HCl (1.5 ml.) in CH2Cl2 (4 ml.) over 30 minutes. The mixture was allowed to stand for a further 30 minutes and then evaporated to dryness. To a solution of the residue, t-butyl 7-[2-(2,2-diethoxyethyl)-3-(tetrahydropyran-2-yl)guanidino]-3-methylceph-3-em-4-carboxylate (1.7 g.) in acetonitrile (8 ml.) was added 3N aqueous HCl (1 ml.) and the mixture was heated at 50° for 2 hours, then evaporated to dryness at 30°. The residue was purified by chromatography on silica gel using CH2Cl2 /MeOH/HOAc 89:10:1 v/v/v as eluant to give, after precipitation from CH2Cl2 solution will ether, t-butyl 3-methyl-7-[5-hydroxy-1-(tetrahydropyran-2-yl)imidazolin-2-yl]aminoceph-3-em-4-carboxylate (900 mg.) as a mixture of diastereoisomers. A solution of this product in trifluoroacetic anhydride was allowed to stand at room temperature under nitrogen for 6 hours, and then evaporated to dryness. The residue was purified by chromatography on silica to give t-butyl 3-methyl-7-(imidazol-2-yl)aminoceph-3-em-4-carboxylate. This compound was treated with trifluoroacetic acid to give the free acid, identical to the product obtained in Example 7.

Provenance & Evidence