Dimethylamine → Drometrizole

Participants

Reaction Steps

25.7 g (0.1 mol) of 2-nitro-2'-hydroxy-5'-methylazobenzene, 0.125 g of palladium carbon, 100 ml of toluene, 50 ml of IPA, 25 ml of water and 7 g of 50% dimethylamine were charged into a 500-ml stainless autoclave with an agitator. After the air in the flask had been replaced by hydrogen, the pressure of hydrogen was set to 10 kg/cm2. Reaction was then effected in the same way as that employed in Example 1. After the reaction had been completed, the catalyst was filtered off, and part of the filtrate was subjected to quantitative analysis using gas chromatography (GC). The results revealed a yield of 81% of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole. The toluene layer was separated, and most part of toluene was then distilled off from the layer. The residual solid was then crystallized using ethanol and then dried to obtain 15.7 g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (yield, 69.8%; melting point, 128° to 130° C.).

Provenance & Evidence