1,2,3,4-Tetrahydro-2-methyl-5H-pyrido(4,3-b)indole-8-carboxylic acid hydrazide hydrochloride 40431-47-8 5H-Pyrido(4,3-b)indole-8-carboxylic acid, 1,2,3,4-tetrahydro-2-methyl-, hydrazide, hydrochloride