NMR spectra revealed the presence of N’-(benzylidene)-2-(6-methyl-1 H-pyrazoloquinolin-1-yl)acetohydrazides as a mixture of two conformers, i.e., E (C=N)(N-N) synperiplanar and E (C=N)(N-N) antiperiplanar at room temperature in DMSO- d 6. The stereochemical behavior of 6( a– t) was studied in dimethyl sulfoxide- d 6 solvent by means of 1H NMR and 13C NMR techniques at room temperature. Structures of the synthesized compounds were established by readily available techniques such as FT-IR, NMR and mass spectral studies. The hydrazinolysis of 3 followed by the condensation of resulting 2-(6-methyl-1 H-pyrazoloquinolin-1-yl)acetohydrazide ( 4) with aromatic aldehydes gave N-acylhydrazones 6( a– t). 2-Chloro-6-methylquinoline-3-carbaldehyde (1) afforded 6-methyl-1 H-pyrazoloquinoline ( 2), which upon N-alkylation yielded 2-(6-methyl-1 H-pyrazoloquinolin-1-yl)acetate ( 3). Twenty new 6-methyl-1 H-pyrazoloquinoline substituted N-acylhydrazones 6( a– t) were synthesized from 2-chloro-6-methylquinoline-3-carbaldehyde ( 1) in four steps. In this article, a synthesis of N’-(benzylidene)-2-(6-methyl-1 H-pyrazoloquinolin-1-yl)acetohydrazides and their structural interpretation by NMR experiments is described in an attempt to explain the duplication of some peaks in their 1H- and 13C-NMR spectra.
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