4H-1,2,4-Triazole-4-acetic acid, 3-(4-chlorophenyl)-1,5-dihydro-5-oxo- synthesis

Yield:-

Reaction Conditions:

Stage #1: ethyl N-({2-[(4-chlorophenyl)carbonyl]hydrazinyl}carbonyl)glycinatewith water;sodium hydroxideReflux;
Stage #2: with hydrogenchloride in water at 20; pH=1;

Steps:

2A

Example 2A[3-(4-Chlorophenyl)-5-oxo-1,5-dihydro-4H-1,2,4-triazol-4-yl]acetic acid Of the compound from Example 1A, 21.43 g (67.93 mmol) were admixed with 91 ml of a 3N aqueous sodium hydroxide solution and heated at reflux overnight. After cooling to RT, the mixture was adjusted to a pH of 1 by slow addition of approximately 20% strength hydrochloric acid. The precipitated solid was isolated by filtration, washed with water and dried at 60° C. under reduced pressure. Yield: 17.55 g (90% of theory, approximately 88% purity).LC/MS [Method 1]: R_t=0.94 min; m/z=254 (M+H)^{+ 1}H NMR (DMSO-d₆, 400 MHz): δ=13.25 (br.s, 1H), 12.09 (s, 1H), 7.65-7.56 (m, 4H), 4.45 (s, 2H).

References:

US2010/261771,2010,A1 Location in patent:Page/Page column 23