Preparation of Extranuclear Halogenoquinoxalines

Most halogenoalkyl- and halogenoarylquinoxalines have been made by primary synthesis (see Chapter 1) or by direct halogenation of alkyl- or arylquinoxalunes (see Section 2.2.4). However, other minor procedures may be used, as illustrated in the following classified examples. 

Extranuclear Halogenoquinoxalines from Corresponding Hydroxyquinoxalines or Acylmethylquinoxalines 

3-Acetonyl-2(l//)-quinoxalinone (231, R = Me) reacted as its tautomer (231a, R = Me) to give 2-chloro-3-(2-chloroprop-l-enyl)quinoxaline (232, R = Me) (POCI3, pyridine, reflux, 10 min 62%) 3-phenacyl-2(l//)-quinoxalinone (231, R = Ph) likewise gave 2-chloro-3-(p-chlorostyryl)quinoxaline (232, 

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