Quinazoline 3-oxide, reaction with active methylene compounds

Quinazoline 3-oxide differs markedly from the 1-oxide in its behavior towards anionic reagents. Whereas with quinazoline 1-oxide compounds a substituent is introduced into po.sition 2 or 4 (cf. p 104), in quinazoline 3-oxide ring fission occurs between C2 and N3 in the reaction with acetic anhydride, water, alkali hydroxide, and under the conditions of the Reissert reaction.2 -(Hydroxyiminomethyl)formanilide is also formed as a byproduct in the reaction of quinazoline 3-oxide with active methylene compounds. ... 

The reaction of quinazoline 3-oxide with active methylene compounds or ketones without a base catalyst similarly results in transformation into quinoline derivatives although in very poor yields (a few percent). ... 

A more detailed study of the reaction with malonitrile revealed that the yields are dependent of the molar ratio malonitrile/quinazoline. The yield increases from 29 (ratio 1.0) to 81% (ratio 2.0), suggesting that the mechanism of the ring transformation involves the contribution of 2 mol of malonitrile. Reaction of quinazoline 3-oxide with the above-mentioned active methylene compounds gives about the same results, although the yields are poor (Scheme 12) (73CPB1943, 75CPB746). 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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