Using an Estero Amide, Nitrile, Acyl Halide, or Related Synthon

Using an Estero Amide, Nitrile, Acyl Halide, or Related Synthon 

A majority of the few available examples in this broad category involve the use of equivalents to the foregoing synthons, as indicated in the following typical cases. 

2- Benzenediamine (270) and the nitrone, ethyl 2-amino-2-(oxidophenylimino) acetate (271) (the equivalent of ethyl carbamoylformate) gave 3-amino-2( 1 //)-quinoxalinone (272) with loss of EtOH and /V-phenylhydroxylamine (EtOH, trace AcOH, 20°C, h 45%).646 

2-Isopropylamino-3-methylaniline (275) and ethoxalyl chloride gave l-isopropyl-8-methyl-2,3(1/7,4/7)-quinoxalinedione (276) (EtPr N, PhMe, —78°C, 1 h then 0°C, 16 h then reflux, 24 h 45%) 729 several analogs were made similarly.729,1016 

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