M-Phenylenediamine → HCID 22765670, compound

Participants

Reaction Steps

the 2-(4-chlorocarbonylphenyl)-5-chlorocarbonylbenzotriazole used in Examples 1 to 9 was prepared in the following way: p-aminobenzoic acid methyl ester is diazotised in the customary manner and the diazo compound is coupled with m-phenylenediamine. The resulting crude azo dyestuff is oxidised in hot pyridine with Cu-II acetate to give 2-(4-methoxycarbonylphenyl)-5-aminobenztriazole with a melting point of 240° C, 135 g of this amine are dissolved in 375 ml of concentrated sulphuric acid and diazotised at 15° to 20° C with nitrosylsulphuric acid. The diazonium salt solution is discharged onto 2.5 kg of ice; the diazonium salt is filtered off and suspended in 800 ml of ice water. This suspension is added in small portions to a solution of 50 g of copper-I cyanide, 75 g of sodium cyanide, 500 ml of water and 250 ml of dimethylformamide. A brown product separates out, with vigorous evolution of gas, and this product can be purified by recrystallisation from o-dichlorobenzene and dimethylformamide; melting point 265° C, blue-fluorescent. The product has the formula ##STR16## and is subjected to alkaline saponification in aqueous glycol monomethyl ether. The product of the formula ##STR17## which melts at 146°-148° C is obtained by boiling in a large excess of thionyl chloride.

Provenance & Evidence