Reactions Involving Initial Diazotization of Aminoquinoxalines

Naturally these reactions are applicable only to primary aminoquinoxalines. The diazonium salt is prepared in aqueous or nonaqueous solution and then converted into the required product as illustrated in the following classified examples. 

8-Methoxy-2,3-diphenyl-6-quinoxalinamine (148, R = NH2) gave 5-methoxy-2,3-diphenylquinoxaline (148, R = H) (substrate, lOM H2SO4, trace H3PO4, trace Cu NaN02/H20i dropwise, 0°C 4°C, 20 h 42%).  

3-(4-Amino-5-methyl-4//-l,2,4-triazol-3-ylmethyl)-2(l//)-quinoxalinone (151, Q = NH2, R = H) gave 3-[a-(5-methyl-4//-l,2,4-triazol-3-yl)-a-nitro-somethyl]-2(l//)-qumoxalinone (151, Q = H, R = NO) [NaN02 ( 2.5 equiv), AcOH, H2O, no further details 97% note additional nitrosation].  

3-Trimethyl-2,3-dihydro-2-quinoxalinamine 1,4-dioxide gave 2,2,3-trimethyl-1,2-dihydro-1-quinoxalinol 4-oxide (Pd/C, MeOH, H2 90% mechanism involed spontaneous loss of NH3).245 

---