Hydrogen Bromide → t-butyl 3-acetoxymethyl-7-(5-hexahydro-1H-azepin-1-ylmethyleneaminomethylbenzimidazol-2-yl)aminoceph-3-em-4-carboxylate

Participants

Reaction Steps

To a solution of t-butyl 3-acetoxymethyl-7-(5-aminomethylbenzimidazol-2-yl)aminoceph-3-em-4-carboxylate (93 mg.) in dioxane (2 ml.) and methanol (3 ml.) at 20° was added dimethoxyhexahydro-1H-azepin-1-ylmethane (30 mg.) and then triethylamine. The mixture was cooled to 0° and stirred for 30 minutes. Two equivalents of HBr in methanol were added and the solvent evaporated. The residue was dissolved in the minimum CH2Cl2 and triethylamine hydrobromide precipitated by addition of ether. The product was purified by chromatography on magnesium silicate using CH2Cl2 /MeOH 98:2 v/v as eluant to give t-butyl 3-acetoxymethyl-7-(5-hexahydro-1H-azepin-1-ylmethyleneaminomethylbenzimidazol-2-yl)aminoceph-3-em-4-carboxylate having the following n.m.r. in d6DMSO: 1.63 (s, 9H); 1.7 (s, 8H); 2.17 (s, 3H); 3.3-4.0 (br, 6H); 4.67 (s, 2H); 4.75 (d, 1H); 5.1 (d, 1H); 5.38 (d, 1H); 6.0 (d, 1H); 6.8-7.5 (m, 3H); 8.43 (s, 1H).

Provenance & Evidence