p-Toluenesulfonic acid → HCID 19352271, compound

Participants

Reaction Conditions

Reaction Steps

300 g of 2-keto-4-(2,3-dimethoxyphenyl)-3-butenoic acid, 2680 ml of toluene, 13.4 g of p-toluenesulfonic acid and 133.8 g of methyl carbamate are placed into a 6 l 4-necked round-bottomed flask in an oil-bath, the mixture is heated to 105° C. for 4 hours with stirring, and the present water is removed azeotropically, the mixture is filtered and the solution is evaporated to dryness under vacuum, then the residue is triturated for about 2 hours with 1260 ml of Et2O, filtered washing with petroleum ether (40-70° C.) and dried under vacuum at 60° C. 313.00 g are obtained. (Yield 94%).

Provenance & Evidence