<span style="font-size:12.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-ansi-language: EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA" lang="EN-US">A reinvestigation of reaction of 2-hydrazino-3-phenylquinoxaline with 1,3-diketones: Synthesis and characterization of regioisomeric 1-(3'-phenylquinoxalin-2'-yl)-3,5-disubstitutedpyrazoles and 1,2,4-triazolo[4,3-<i style="mso-bidi-font-style: normal">a</i>]quinoxalines</span>

273-281A reinvestigation into the reaction of 2-hydrazino-3-phenylquinoxaline 1 with several 1,3-diketones 2a-g reveals that a mixture of regioisomeric 1-(3'-phenylquinoxalin-2'-yl)-3,5-disubstitutedpyrazoles <b style="mso-bidi-font-weight: normal">3a-g and <b style="mso-bidi-font-weight: normal">4a-e and 1-methyl-4-phenyl/methyl-1,2,4-triazolo[4,3-a]quinoxalines <b style="mso-bidi-font-weight: normal">5a,b is formed as reaction products rather than erroneously reported exclusive formation of triazole 5 in case of aryl alkyl-1,3-diketones or 1-(3'-phenylquinoxalin-2'-yl)-3-alkylpyrazoles 4 in case of dialkyl and diaryl-1,3-diketones. Structural elucidation of the regioisomeric pyrazoles has been established by the spectroscopic data (1H, 13C NMR, COSY experiments and HRMS) and minimum energy 3-D diagrams.