1-Methyl-2-nitroso-1,2,3,4-tetrahydo-beta-carboline-3-carboxylic acid 1H-Pyrido(3,4-b)indole-3-carboxylic acid, 2,3,4,9-tetrahydro-1-methyl-2-nitroso- 23708-74-9 Mnthcc