A facile synthesis of novel triazoloquinoxahnones and triazinoquinoxalinones

Abstract

A series of 1‐aryl‐s‐triazolo[4,3‐a]quinoxalin‐4‐ones, 3, were synthesized via the pyrolysis of the corresponding hydrazones, 6. Thus, the cyclodehydrogenation occurred by refluxing them in an inert solvent (e.g. ethylene glycol) to give the triazoloquinoxalin‐4‐ones in a satisfactory yield. Using DMSO as a solvent for the above transformation afforded as a minor by‐product an S‐ylid. In contrast to earlier findings, annelation of a six‐membered ring was successful and achieved through the pyrolysis of the pyruvate hydrazones derived of the quinoxalin‐4‐ones at −230° to give the as‐triazino[4,3‐a]quinoxalin‐5‐ones, 4. The reaction of 5 with acetylacetone afforded 3‐(3′,5′‐dimethylpyrazol‐1‐yl)‐2(1H)‐quinoxalinone, 10. The structural assignments for the new compounds were based on their elemental analysis and spectroscopic data as well as an independent synthesis.

Synthesis and Antimicrobial Activity of Some Novel Hydrazide, Pyrazole, Triazine, Isoxazole, and Pyrimidine Derivatives

“…From the activity data, compounds 5 and 16 showed the highest antibacterial inhibition, thus suggesting that the compounds from the present series with electron withdrawing groups can serve as important gateways for the design and development of new antimicrobial agents with potent activity and minimal toxicity. General procedure for the synthesis of 3-(4-substituted)-2-cyano-N-(2-methoxynaphthalen-1-yl)methylene)acrylohydrazide derivatives (2)(3)(4). Equimolecular mixture of compound 1 (0.26 g, 1 mmol) and selected aldehyde (1 mmol), in absolute ethanol (25 mL) containing piperidine (0.5 mL), was heated under reflux for 3 h. The reaction mixture was left to cool, and the formed solid product was filtered off, dried, and recrystallized from ethanol to afford compounds 2-4.…”

“…The chemistry of a carbon-nitrogen double bond of hydrazone is becoming the vertebrae of condensation reaction in benzo-fused N-heterocycles [3]; also, it constitutes an essential class of compounds for new drug development [4]. A number of hydrazide-hydrazone derivatives have been claimed to have exciting bioactivity such as antimicrobial, antitubercular [5,6], anticonvulsant [7], analgesic [8], anti-inflammatory [9,10], antiplatelet aggregation [11], anticancer [12,13], antifungal [14], antiviral [15], antibacterial [16], and antimalarial [17] activities.…”

Spectral and conformational studies on 3-pyridinealdazine by DFT approach

“…The chemistry of carbon nitrogen double bond of hydrazone is becoming the backbone of condensation reaction in benzo-fused Nheterocycles [3] also it constitutes an important class of compounds for new drug development [4]. A number of heterocyclic compounds have been shown to possess pharmacological activities [5][6][7].…”

Synthesis and Antimicrobial Activity of Condensed and Uncondensed Quinoxalines

“…Tetrazolo[l,5-a]quinoxalines were also showed fungicidal (12) activities. In the course of our investigations towards the synthesis of different heterocyclic derivatives from α-keto acids (13)(14)(15), we have carried out the preparation of the title compounds.…”