β-Oxo anilides in Heterocyclic Synthesis: Novel Synthesis of Polyfunctionally Pyridines, Pyrimidines and Benzothiazole Derivatives

Hussein, Abdelhaleem M; El-Gaby, Mohamed; Abushanab, Fathi; Abdel-Raheim, Mohamed; Elapasery, Morsy

doi:10.21608/ejchem.2018.3925.1344

β-Oxo anilides in Heterocyclic Synthesis: Novel Synthesis of Polyfunctionally Pyridines, Pyrimidines and Benzothiazole Derivatives

Document Type : Original Article

Authors

¹ Department of Chemistry, Faculty of Science, Al Azhar University, Assiut 71524, Egypt

² Dyeing, Printing and Auxiliaries Department, Textile Research Division, National Research Centre, Cairo 12622, Egypt

10.21608/ejchem.2018.3925.1344

Abstract

Acetoacetanilide derivative 1 was reacted with aromatic aldehydes 2 to yield the arylidine derivatives 3 and 6a, b. The Hantzsch amides 7a,b were prepared by the one-pot cyclization reaction of a mixture of 2 moles of 1, aqueous ammonia and aromatic aldehydes. Treatment of 1 with ethanol containing equivalent amount of piperidine or morpholine furnished the isolable products 8a and 8b. Compound 1 underwent interamolecular heterocyclization on boiling conc. sulfuric acid, afforded 9. Also, the reaction of compound 1 with hydroxylamine hydrochloride in ethanol and sodium acetate afforded the oxime derivative 10. Furthermore, reactions of compound 1 with o-aminothiophenol furnished 11. Reactions of 1 with arylidine derivatives give compounds 13 and 16a-d. Treatment of compound 16d with elemental sulfur afforded the thieno[3,4-c]pyridine derivative 18. Treatment of 16a with hydrazine hydrate in boiling ethanol afforded the pyrazolo[3,4-b]pyridine derivatives 19. Also, compound 16a was reacted with ethylchloroacetate giving 20. Compound 20 was cyclized into the corresponding thieno[2,3-b]-pyridine derivative 21 upon boiling with ethanol containing a few drops of sodium ethoxide solution. Furthermore, compound 1 readily reacted with cyanothioacetamide to yield compound 22. Fusion of compound 1 with malononitrile over melting point without solvent in presence of ammonium acetate or refluxing in ethanolic piperidine afforded the pyridone 23a. Also, the pyridone derivative 23b was obtained by reacting compound 1 with cyanoacetamide. The reaction of acetoacetanilide 1 with -bromoacetophenones afforded 28a,b. Treatment of 1 with benzoyl and ethoxy carbonyl isothiocyanates afforded the pyrimidine derivatives 30a,b. The reaction of 1 with aminopyrazole gave the pyrazolopyrimidine 33. Coupling of 1 with diazonium salt of compounds 34a,b yielding 37a,b.

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