[CH3:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8](=[N:15][NH2:16])[C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.[I-].CN(C)C(N(C)C)=N.C(OO)(=O)C>ClCCCl>[CH3:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)=[N+:15]=[N-:16]To (2-methylphenyl)phenyl ketone hydrazone (10.5 g, 0.05 moles) dissolved in 1,2-dichloroethane (50 ml) containing iodide (2 ml, 1% w/v solution) and 1,1,3,3-tetramethylguanidine (22.5 ml) was added peracetic acid solution (11.4 ml, 1.27 × 0.05 moles) at 0° over 30 minutes. After the addition the mixture was stirred for 5 minutes longer. The red solution was washed with water (5 × 200 ml), dried over sodium sulphate and made up to 250 ml in a volumetric flask. An aliquot (50 ml) treated with excess acetic acid yielded 221 ml gas corrected to NTP which corresponded to a 98.6% yield of diazoalkane. The compound was characterised by a major absorption at 2050 cm-1 and λmax 516 nm. A solid ester derivative was made by treating (5R, 6R, 1S, 3S)-2,2-dimethyl-6-phenylacetamidopenam-3-carboxylic acid 1-oxide in chloroform with an aliquot of the diazoalkane solution. After gas evolution had ceased the slightly yellow solution was washed with 5% sodium bicarbonate solution, water, and the organic residue left after removal of the organic solvent crystallised from hot propan-2-ol. The solid was identified as (2-methylphenyl)phenylmethyl (5R, 6R, 3S, 1S)-2,2-dimethylpenam-6-phenylacetamidopenam-3-carboxylate 1-oxide by its n.m.r. spectrum and melting point and mixed melting point 140° - 145° with an authentic sample of the ester.
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