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The formation of (E)-3-{2-(2,5-diphenylpyrazolo[1,5-c]pyrimidin-7-yl)hydrazono}indolin-2-ones 3 has been achieved by condensation of equimolar amounts of 7-hydrazino-2,5-diphenylpyrazolo[1,5-c]pyrimidine (1) and isatin (or isatin derivatives) 2 at room temperature. The (E)-products could be isomerized into corresponding the (Z)-3 isomers. Reactions of the latter fused heterocyclic hydrazones towards different electrophilic reagents yielded the corresponding 3-substituted derivatives 4-7. Dehydrative cyclisation of the hydrazones 3 using phosphorus oxychloride afforded the 2,5-diphenylindolo[ 2,3-e]pyrazolo[1′,5′:3″,4″]pyrimido[2″,1″-c][1,2,4] triazines 13. The polyfused heterocyclic ring system 13 underwent electrophilic substitution reactions at position 4 rather than at position 3. The 3-bromo isomer of 17 was prepared by a sequence of reactions starting from 2,5-diphenylpyrazolo[1,5-c]pyrimidine-7(6H)-thione (11). The orientation of the electrophilic attack was supported by spectroscopic and chemical evidence. Some of the synthesized compounds were found to possess slight to moderate activity against the microorganisms Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

Synthesis of {3-[1-(ethoxycarbonyl)-[1,2,4]triazolo[4,3-a]quinoxalin-4-yl]-1-phenyl-1 H-pyrazol-5-yl}methyl ethyl oxalate ( 2), ethyl 4-[5-(acetoxymethyl)-1-phenyl-1 H-pyrazol-3-yl]-[1,2,4]triazolo[4,3-a]quioxaline-1-carboxylate ( 4), [4-halo-1-phenyl-3-(1-phenyl-[1,2,4]triazolo[4,3-a]quioxalin-4-yl)-1 H-pyrazol-5-yl]methyl acetate ( 11), {4-halo-3-[1-methyl-[1,2,4]triazolo[4,3-a]quinoxalin-4-yl]-1-phenyl-1 H-pyraz-ol-5-yl}methyl acetate ( 13), and [3-([1,2,4]triazolo-[4,3-a]quinoxalin-4-yl)-4-halo-1-phenyl-1 H-pyrazol-5-yl] methyl formate ( 15) was accomplished. The structural investigation of the new compounds is based on chemical and spectroscopic evidences. J. Heterocyclic Chem., (2011) [ABSTRACT FROM AUTHOR]

5-Aryl-7-hydrazino-2-phenylpyrazolo[1,5-c]pyrimidines 1 were used as precursors for the preparation of a new series of 5-aryl-8-phenylpyrazolo[1,5-c]-1,2,4-triazolo[4,3-a]pyrimidines 2. The reactions of 2 with certain electrophilic reagents gave the respective 6-substituted derivatives 3-5 rather than the 7-isomeric products. Formylation of the key compounds 1 with ethyl formate yielded the formyl derivatives 6. Furthermore, boiling of compounds 1 with acetic acid afforded 7-acetylhydrazino-5-aryl-2-phenylpyrazolo[1,5-c]pyrimidines 7. Bromination of 7 yielded the dibromoderivatives 8, while their iodination and nitration gave the monosubstituted derivatives 9 and 10, respectively. Also, treatment of 1 with boiling acetic anhydride yielded the triacetyl derivatives 11. The structure of synthesized products was confirmed by elemental analyses, IR, 1H NMR and MS spectra. [ABSTRACT FROM AUTHOR]

Sulfanyl-glycosides have been synthesized by reaction of 2,3-dimercaptoquinoxaline () with acetohalo sugars in presence of base to give the thioglycosides-derived quinoxalines - and . Similarly, the acyclic analogs - were prepared by coupling of with different acyclo-alkylating agents. The preparation of 3-morpholinyl-quinoxalines and allowed the synthesis of 3-glycosylsulfanyl-2-morpholinyl-quinoxalines - and as well as the acyclic analogs -. Microwave irradiation of the reactants turned out to be preferred over the conventional method for achieving the synthetic goals. This study made an available venue to the synthesis of diverse quinoxaline derivatives. J. Heterocyclic Chem., 2011. [ABSTRACT FROM AUTHOR]

Review: 76 refs. [ABSTRACT FROM AUTHOR]