Extranuclear Hydroxyquinoxalines

6-Bromo-7-methoxy-5,8-quinoxalinequinone (148) and a-phenylstyrene (147) gave 5-phenylnaphtho[l,2-g]quinoxaline-7,12-quinone (150), probably via the intermediate (149) (PhH, pyridine, 20°C, hv, 30 min 12% analogs likewise but also in poor yield). 

These hydroxyquinoxalines may be considered as regular alcohols or phenols because their formation and reactions are negligibly affected by the heterocyclic system or its nuclear substituents. 

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Extranuclear Hydroxyquinoxalines By Passenger Introduction of Hydroxy Groups... 

Extranuclear hydroxyquinoxalines react as do regular alcohols or phenols. Examples of theii conversion into alkylquinoxalines (Section 2.2.1.5) ox conversion into extranuclear halogenoquinoxalines (Section 3.3) have been given already. Other reactions are illustrated by the following classihed examples. 

Most alkoxy- or aryloxyquinoxalines have been made by primary synthesis (see Chapter 1), by alcoholysis or phenolysis of halogenoquinoxalines (see Sections 3.2.2 and 3.4.2), or by 0-alkylation of tautomeric quinoxalinones or extranuclear hydroxyquinoxalines (see Sections 4.1.2.2 and 4.3.2). The remaining preparative routes are illustrated by the following classified examples. 

Extranuclear Halogenoquinoxalines from Corresponding Hydroxyquinoxalines or Acylmethylquinoxalines... 

Many such hydroxyquinoxalines have been made by primary synthesis (see Chapter 1) and some by hydrolysis of extranuclear halogenoquinoxalines (see Section 3.4.2) in addition, during extranuclear alkylidenation of methylquinox-alines (see Section 2.2.1.4) the intermediate secondary alcohols may sometimes be isolated, especially with heavily substituted aldehydes, when dehydration can be difficult or even impossible. ° ... 

These ethers, both nuclear and extranuclear, undergo a few useful reactions, including hydrolysis to corresponding quinoxalinones or hydroxyquinoxalines, which has been covered in Sections 4.1.1 and 4.3.1, respectively. The other reactions are illustrated in the following classified examples. 

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