Abstract
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 Rf values were recorded. The synthesized compounds were confirmed via the spectral data (UV,I.R,1H-NMR, 13C-NMR, mass spectra). The possible fragmentation pattrene of GC/MS for the compounds (IVa) were investigated (IVh).).
Highlights
Nitrogen - containing heterocycles are present in both natural products and pharmaceuticals
The literatures showed that the pyridoquinazolines derivatives have biological activities such as antitumor agent (Palop et al, 2014; Shabana, 2013; Palmer et al, 2012), antibacterial (Yassin, 2009), anticonvulsant (Laddha et al, 2009), anti – inflammatory and anti – allergic activities (Chandrika et al, 2008), analgesic, and anti - inflammatory
The purity of the compounds was ascertained by thin layer chromatography (TLC) on pre-coated silica gel glass plates using either UV radiation or iodine staining for visualization
Summary
2-[(6-chloro-2-pyridyl) amino]benzoic acid (I) was synthesized through nucleophilic aromatic substitution of anthranilic acid with 2,6-dichloropyridine using anhydrous K2CO3 as a base, CuO as a catalyst and phenol as a solvent (Ullmann reaction) as shown in the following equation. The structure of the synthesized compound (I) was confirmed by means of physical (m.p, Rf) and spectral data. The IR spectra showed a characteristic absorption band in the region (3350-3100 cm-1, broad) stretching band for (OH, NH) groups respectively, (1670 cm-1) stretching band for (C=O) group, (1610 cm-1) stretching band for (C=N) group, (1595 cm-1) stretchingband for (C=C) group. The 1H-NMR spectral for compound (I) Fig. The 1H-NMR spectrum for compound (I)in (DMSO-d6) δ in ppm showed the significant peaks as the follows: broad at 4.55-6.45 for 1H (NH), multiple at 6.45-8.48 for 7H(ArH), broad peak at 9.82-10.19 due to. The compound (II) was prepared by cyclization of the acid (I) by using (PPA) according to the following mechanism: Cl N N H (I)
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