A hydrogen-bonded chain of rings in 5-amino-1-(4-methoxybenzoyl)-3-methylpyrazole and a three-dimensional hydrogen-bonded framework in 5-amino-3-methyl-1-(2-nitrobenzoyl)pyrazole
摘要:
The molecules of 5-amino-1-(4-methoxybenzoyl)-3-methylpyrazole, C12H13N3O2, (I), and 5-amino-3-methyl-1-(2-nitrobenzoyl) pyrazole, C11H10N4O3, (II), both contain intramolecular N-H center dot center dot center dot O hydrogen bonds. The molecules of (I) are linked into a chain of rings by a combination of N-H center dot center dot center dot N and N-H center dot center dot center dot pi(arene) hydrogen bonds, while those of (II) are linked into a three-dimensional framework structure by N-H center dot center dot center dot N and C-H center dot center dot center dot O hydrogen bonds.
A series of 5-amino-1-aroylpyrazoles 3 are synthesized directly by the reaction of beta-aminocrotononitrile 1 with some structures containing the hydrazine moiety (X-NHNH2) 2 by refluxing ethanol in presence of sodium acetate. When semicarbazide 3i was used (X = CONH2), the reaction afforded the unexpected 7-aminopyrazolo[1,5-a]pyrimidine 4. (C) 2008 Elsevier Ltd. All rights reserved.