The 2-[(6-chloro-2-pyridyl) amino]benzoic acid (I) was synthesized viaUllmann-Goldberg coupling by reaction of anthranilic acid with2,6-dichloropyridine. The compound (I) was cyclized by using poly phosphoric acid (PPA) to give 9-chloro-11H-pyrido[2,1-b]quinazolin-11-one (II). The compound (II) reacted with hydrazine hydrate to give N-{11H-pyrido[2,1-b]quinazolin-11-one-9-yl} hydrazine (III). The compound (III) reacted with various aromatic aldehydes to yield the hydrazones (IVa-p). The reaction progress was followed by thin layer of chromatography (TLC). The physical constants and R f values were recorded. The synthesized compounds were confirmed via the spectral data (UV,I.R, 1 H-NMR, 13 C-NMR, mass spectra). The possible fragmentation pattrene of GC/MS for the compounds (IVa) were investigated (IVh).
The N-(4-methyl-2-pyridyl)anthranilic acid (I) was synthesized by Ullmann condensation. The compound (I) was cyclized by polyphosphoric acid (PPA) to give 4-methyl-10Hbenzo[b][1,8]naphthyridin-5-one (II). The compound (II) was treated with selenium dioxide (SeO 2) and thionyl chloride (SOCl 2) to give the 4-formyl-10H-benzo[b][1,8]naphthyridin-5-one (III) and 4methyl-5-chloro-benzo[b][1,8]naphthyridine (IV) respectively.The compound (III) was reacted with various substituted anilines and aliphatic amines to give the Schiff bases (Va-j). The compound (IV) was reacted with hydrazine hydrate to yield the 5-hydrazino derivative (VI), which was reacted with various aromatic aldehydes to yield the hydrazones (VIIa-j) and the R f values reported.The reaction progress was followed by thin layer chromatography (TLC). The synthesized compounds were confirmed by spectral data (I.R, 1 H-NMR, 13 C-MNR). The possible fragmentation pattern of GC/MS for the compounds (III), (Vc) and (VIIg) were reported.
In this paper, some new bis-acyl hydrazone derivatives (4a-f) were prepared through the reaction of carboxylic acid hydrazides with 1,4-diacetylbenzene using classical methods, microwave and ultrasound irradiation methods. These compounds are obtained through a series of reactions where some carboxylic acids react with ethanol first in the presence of concentrated sulfuric acid to give the corresponding esters (2a-f), which when treatment with aqueous hydrazine give carboxylic acid hydrazides (3a-f).thus, The results proved that the use of microwave and ultrasound techniques is much better than the classical methods, as it gave a higher yield, shorter reaction time, and the absence of the use of solvents. All newly synthesized compounds were confirmed by IR, ( 1 H & 13 C) NMR spectral analysis and the corresponding reactions were monitored by TLC using the reported eluent.
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