Saoud A. Metwally

Heterocyclic compounds. VIII. Studies on oxazolophenoxazines

5H-Oxazolo[4,5-b]phenoxazine (5) was synthesized by the reaction of 3-amino-2-hydroxyphenoxazine hydrochloride (2) with formamide. A series of styryl-oxazolophenoxazines (9) were prepared by condensation of 2-methyl-5-acetyloxazolo[4,5-b]phenoxazine methiodide (8) with aromatic aldehydes. By contrast, 2-aryl-oxazolophenoxazines (14) were synthesized by reaction of 3-aminophenoxaz-2-one (1) with the appropriate aldehydes in the presence of an acid–base catalyst. The biological activities of some of these compounds were tested.

STUDIES WITH POLYFUNCTIONALLY SUBSTITUTED HETEROAROMATICS: THE REACTIVITY OF ALKYLAZOLES TOWARDS ELECTROPHILIC REAGENTS

Abstract Several new condensed thiazoles and thiazoles and thiazoles are synthesized. The reactivity of alkylazoles towards electrophilic reagents is reported. New synthesis of thenylthiadiazoles, thiadiazo-lopyridines and pyridazines could be achieved.

Synthesis of some heterocycles of potential biological activity

A convenient method for the preparation of imidazobenzimidazole3, imidazoimidazole5, imidazotriazole6 and pyrano [2, 3-c] oxazole7 derivatives is described. This depends on interaction of 2-methyl-4-arylidene-2-oxazolin-5-ones1 with o-diamines, thiosemicarbazide and/or ethylcyanoacetate. The effect of alcoholic potassium cyanide on oxazolinone1 was studied. Antibacterial activity of the obtained products was studied.

An electronic spectral study of the coupled effect on the tautomeric equilibria of some α-hydroxy azo compounds

Abstract The spectral behaviour of six a-hydroxy azo compounds has been investigated in solution. The bands appearing in the u.v. and visible regions are assigned to possible electronic transitions. Azo compounds containing pyrazolone and acetyl or ester moieties are found to exist mainly in the hydrazo form in solution, while those containing the naphthol moiety exist in the azo-hydrazone tautomeric equilibrium. The solvatochromic behaviour of the compounds is investigated by studying their spectra in organic solvents of different polarities. The acidity constants are determined from the spectra of the compounds in aqueous ethanolic solutions of varying pH values.

REACTIONS OF 4-ALKYLIDENE (ARYLIDENE)-1-PHENYLPYRAZOLIDINE-3,5-DIONE

Reactions of 4-alkylidene(arylidene)-1-phenylpyrazolidine-3,5-dione with oxidizing (chromium trioxide/acetic acid) as well as with reducing (sodium borohydride/methanol) agents were carried out. Phenylhydrazine reacted with 4-arylidene-1-phenylpyrazolidine-3,5-diones via fission of exo C=C bond to give 1-phenylpyrazolidine-3,5-dione and the corresponding aryl hydrazones.

Synthesis of Some New 2-Substituted Thiazolid-4-ones

2-Substituted thiazolid-4-ones were prepared by interaction of thioglycolic acid with certain acyl derivatives in presence of ammonium carbonate and dry benzene. The reaction mechanism is discussed.

Synthesis and some reactions of 3-methyl-4-aryl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine-6-thiols

Abstract 3-Methyl-4-aryl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine-6-thiols(II) were synthesised by the interaction of thiourea with 3-methyl-1-phenyl-4-arylidene-2-pyrazolin-5-ones(I) in ethanolic potassium hydroxide. The mechanism of this synthesis is discussed and the reaction of the products with different reagents was carried out.