p-Nitrobenzyl 2,2-dimethyl-6-(imidazol-2-yl)aminopenam-3-carboxylate toluene-p-sulphonate → 2,2-Dimethyl-6-(imidazol-2-yl)aminopenam-3-carboxylic acid toluene-p-sulphonate

Participants

Reaction Steps

A solution of p-nitrobenzyl 2,2-dimethyl-6-(imidazol-2-yl)aminopenam-3-carboxylate toluene-p-sulphonate (360 mg.) in a mixture of ethanol (18 ml.) and CH2Cl2 (5 ml.) was hydrogenated at atmospheric pressure for 3 hours in the presence of 10% w/w palladium-on-carbon (180 mg.). The mixture was filtered, the filtrate evaporated and the residual yellow gum triturated with ether to give 2,2-dimethyl-6-(imidazol-2-yl)aminopenam-3-carboxylic acid toluene-p-sulphonate as a yellow solid (258 mg.) having the following n.m.r. in d6DMSO: 1.5 (s, 3H); 1.6 (s, 3H); 2.30 (s, 3H); 4.35 (s, 1H); 5.46 (d, 1H); 5.66 (d, 1H); 6.97 (s, 2H); 7.10 (d, 2H); 7.50 (d, 2H); 8.7-9.0 (br, 1H). By integration the product was 50% pure and contained 2 moles of toluene-p-sulphonic acid per mole of β-lactam.

Provenance & Evidence