With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.3405-77-4,5-Methylisoxazole-3-carboxylic acid,as a common compound, the synthetic route is as follows.
a 5-Methyl-3-isoxazolecarboxylic Acid 2-(Pyrido[3,4-d]pyridazin-4(3H)-one-1-yl)hydrazide 1-Hydrazinopyrido[3,4-d]pyridazin-3(4H)-one [prepared by the method of K. Kormendy, T. Kovacs, F. Ruff and I. Kovesdi, Acta Chim. Hung., 1983, 112(4), 487] (1.72 g, 9.7 mmol), triethylamine (1.36 ml, 9.7 mmol), 5-methylisoxazole-3-carboxylic acid (1.23 g, 9.7 mmol) and bis(2-oxo-3-oxazolidinyl)phosphinic acid (2.48 g, 9.7 mmol) in 1,2-dichloroethane (60 ml) were heated at reflux under nitrogen for 18 h. The mixture was allowed to cool and diluted with water (20 ml). The precipitate was filtered off and washed successively with water (2*50 ml) and diethyl ether (2*50 ml) to give the title compound (2.2 g, 79percent), 1H NMR (400 MHz, d6 DMSO) delta 2.50 (3H, s, Ar-CH3), 6.62 (1H, s, Ar-H), 8.04 (1H, d, J=5.5 Hz, Ar-H), 9.10 (1H, d, J=5.5 Hz, Ar-H), 9.11 (1H, s, Ar-H), 9.45 (1H, s, NH), 10.62 (1H, s, NH), 12.08 (1H, s, NH).
As the paragraph descriping shows that 3405-77-4 is playing an increasingly important role.
Reference£º
Patent; Merck Sharp & Dohme Ltd.; US6613766; (2003); B1;,
Isoxazole – Wikipedia
Isoxazole | C3H3NO – PubChem