A convenient one-pot synthesis of 4-amino-3-arylpyrazoles from α-phthaloylaminoacetophenones

✍ Scribed by Chen Chen; Keith Wilcoxen; James R. McCarthy

• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 212 KB
• Volume: 39
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(98)01776-6

✦ Synopsis

Condensation of c¢-phthaloylaminoacetophenones la.-c with N,N-dimethylformamide dimcthyl acetal afforded the novel enamines 3a-c. Cyclization of 3 with hydrazine, alkylhydrezine or phenylhydrazine salts (4a-d) gave 4-phthaloylamino-3-arylpyrazoles 7-9 in high yields. Deprotection of 7-9 was accomplished with hydrazine to provide 4-amino-3-arylpyrazoles 5 in good yields.