The vaporization enthalpies of 1-methyl-, 1-ethyl-, 1-phenyl-, and 1-benzylimidazole, 1-methyl- and 1-phenylpyrazole, and trans-azobenzene are evaluated by correlation-gas chromatography (C-GC) using a variety of azines and diazines as standards. The vaporization enthalpies obtained by C-GC when compared to literature values are approximately 14 kJ·mol(-1) smaller for the imidazoles and 6 kJ·mo...

pyrazoles and isoxazoles are well-known important heterocyclic compounds that due to their participation in the structure of many drugs are very important. pyrazoles and isoxzaloes can be prepared by oxidation of pyrazolines and isoxazolines respectively. in this work, trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxalane (dhpdmdo)/nh4i has been used as a new, powerful, nearly green, effective and...

Pyrazoles and isoxazoles are well-known important heterocyclic compounds that due to their participation in the structure of many drugs are very important. Pyrazoles and isoxzaloes can be prepared by oxidation of pyrazolines and isoxazolines respectively. In this work, trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxalane (DHPDMDO)/NH4I has been used as a new, powerful, nearly green, effective and...

Pyrazoles and isoxazoles are well-known important heterocyclic compounds that due to their participation in the structure of many drugs are very important. Pyrazoles and isoxzaloes can be prepared by oxidation of pyrazolines and isoxazolines respectively. In this work, trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxalane (DHPDMDO)/NH4I has been used as a new, powerful, nearly green, effective and...

The solvent-free reaction between 5-amino-1H-pyrazoles and -triketones (2-acetyldimedone and 2acetylindandione) leads to the formation of new fused pyrazolo[1,5-a]pyrimidines in good yields. A possible mechanistic route is postulated on the basis of the isolation of the cyclization intermediate. The structures and regiospecificity of the reaction were determined on the basis of nmr measurements...

A novel series of 7,7-diphenyl-1,2-dihydroimidazo[2,1-c][1,2,4]triazin-6(7H)-one 6a-h, were easily prepared via reactions of novel 2-hydrazinyl-4,4-diphenyl-1H-imidazol-5(4H)-one (2) with hydrazonoyl halides 3a-h. In addition, we also examined the reaction of compound 2 with commercially available active methylene compounds to afford new pyrazoles containing an imidazolone moiety, expected to b...

2,3-dihydro-1H-pyrazoles were highly selectively synthesized via the Pd(0)-catalyzed coupling-cyclization reaction of 4-non-substituted 2-substituted 2,3-allenyl hydrazines with aryl iodides in moderate to good yields.

Pyrazoles are very important class of biologically active compounds and many of their derivatives are in clinical use. Pyrazole derivatives have been shown to exhibit antihyperglycemic [1], hypoglycemic [2] and fungicidal properties [3]. Some of them are also used as insecticides and herbicides [4,5]. Of the condensed pyrazoles, specially pyrano[2,3-c]pyrazole is a fused heterocycle comprising ...

5-Amino-N-aryl-3-[(4-methoxyphenyl)amino]-1H-pyrazole-4-carboxamides 4a-c were synthesized by the reaction of N-(aryl)-2-cyano-3-[(4-methoxyphenyl)amino]-3-(methylthio)acrylamides 3a-c with hydrazine hydrate in ethanol. The reaction of 5-amino-N-aryl-1H-pyrazoles 4a-c with acetylacetone 5 or 2-(4-methoxybenzylidene)malononitrile 8 yielded the pyrazolo[1,5-a]pyrimidine derivatives 7a-c and 10a-c...