Quinolines electrophilic substitution, regioselectivity

Further studies of electrophilic substitution using the 2,3-dihydrothiazolo analogue (320) show that regioselective bromination can be effected in the 7-position (347) at low temperature. Chlorination with sulfuryl chloride, however, occurs exclusively in the 5-position. The 5-chloro derivative (348) can be further nitrated in the 7-position. By analogy, bromination of quinoline analogues (349) occurs in the azine ring, in the 5-position. The [3,2-a]pyrimidine analogue (350 R=H) similarly yields the 7-bromide. The activation by... 

Reactions of benzodiazines show no exceptional features compared with the simple diazines. Reactivity towards electrophiles is less than in quinoline and isoquinoline. If S Ar reactions take place, they lead to substitution of the benzene ring. As a rule, nucleophilic substitution of benzodiazines occur in the diazine ring, particularly if substituted by halogen. The quinazoline system displays C-4 regioselectivity, e.g. in the reactions of 2,4-dichloroquinazoline with amines or alcohols ... 

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