Chemistry of substituted quinolinones. Part 8. Synthesis and cyclization reactions of ethyl 5-amino-1-(1-methyl-2-oxoquinolin-4-YL)-3-methylsulfanylpyrazole-4-carboxy late

摘要

The synthesis of the titled amino-ester 3 is described and its hydrolysis and chloroacetylation led to the acid 5 and acetamide 7, which were cyclized to the pyrazolopyridones 6 and 8, respectively. Condensation of 3 with 2,5-dimethoxytetrahydrofuran afforded the pyrrolylpyrazole 9, which underwent cyclization by action of PPA to give pyrazolopyrrolizine 10. Treating 3 with thiophosgene gave the pyrazolyl isothiocyanate 11, which added aniline to yield the thiourea derivative 12, and cyclized to give pyrazolopyrimidinethiones 13-15. Condensation of 3 with formamide furnished pyrazolopyrimidine 16, while with triethyl orthoformate produced the ethoxymethyleneaminopyrazole 18, which condensed with hydrazine to give the aminopyrazoloprimidine 19. Reaction of 3 with Lawesson's reagent resulted in the pyrazolothiazaphosphinine 21. Also the cyclization reaction of the compound 3 with malononitrile and its mixtures with carbon disulfide, phenyl isothiocyanate, or benzaldehyde led to the formation of a variety of polyfunctional substituted pyrazolopyrimidines 23 and 26, pyrazolothiazine 24 and pyrazolopyridine 28. [References: 24]