Isoquinolines electrophilic substitution, regioselectivity

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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