Synthesis, Antiviral, and Antimicrobial Activity of <i>N</i>‐ and <i>S</i>‐Alkylated Phthalazine Derivatives

Abstract

A series of N ‐alkylphthalazinone were synthesized by the reaction of phthalazin‐1(2 H )‐one derivatives 1a , 1b , 1c with alkylating agents namely, propargyl, allyl bromide, epichlorohydrin, 1,3‐dichloro‐2‐propanol, 4‐bromobutylacetate, and 1‐(bromomethoxy)ethyl acetate to give the corresponding N ‐alkylphthalazinone 2a , 2b , 2c , 3a , 3b , 3c , 5a , 5b , 5c , 6a , 6b , 6c , 7a , 7b , 7c , and 9a , 9b , 9c . Alkylation of phthalazin‐1(2 H )‐thione to give a series from S ‐alkylphthalazine 12 , 13 , 14 and thioglycosides 15 and 17 was performed. Deprotection of compounds 7a , 7b , 7c , 9a , 9b , 9c , 15 , and 17 resulted in the formation of the corresponding products 8a , 8b , 8c , 10a , 10b , 10c , 16 , and 18 . The structure of newly synthesized compounds was assigned by IR, 1 H, 13 C NMR, and elemental analysis. Some of these compounds were screened for antiviral and antimicrobial activity.