Synthesis and Biological Screening of 4-Benzyl-2H-phthalazine Derivatives

Abstract

Preparation of 4-benzyl-2-substituted phthalazin-1-one derivatives 2-8 is reported. Condensation of 4-benzyl-1-chlorophthalazine (9) with a series of different nucleophiles gave 4-benzylphthalazin-1-ylamino derivatives (10-13 and 16) and 4-amino-2-[N′-(4-benzylphthalazin-1-yl)-hydrazino]-6-arylpyrimidine-5-carbonitriles (14a,b). Interaction of 9 with ambident anions was also studied. 5-Benzyl-6,6a,12-triazobenzo[a]-anthracen-7-one (15) is obtained from 9 and anthranilic acid derivatives. Treatment of 16 with (EtO)3CH/Ac2O under reflux afforded the corresponding ethoxymethylene derivative 17, while aqueous ammonium hydroxide treatment afforded carboxamide derivative 18. The structures of the newly synthesized derivatives were confirmed by their elemental analysis, IR, 1H NMR, 13C NMR and mass spectral studies. Antimicrobial activities of some selected compounds were also studied and some of these were found to exhibit promising effects against Gram-positive and Gram-negative bacteria and fungi.

Design and Synthesis of New Phthalazinone Derivatives Containing Benzyl Moiety with Anticipated Antitumor Activity

“…The commercially available phthalic anhydride was fused with phenylacetic acid in the presence of fused sodium acetate in an oil bath at 180°C to afford the 3-benzylidenephthalide 1, which was then reacted with hydrazine hydrate 31) in boiling ethanol to give the benzylphthalazinone derivative 2. Oxidation of the phthalazinone derivative 2 with KMnO 4 in the presence of K 2 CO 3 was failed to give 2,3-dihydrophthalazine-1,4-dione A, this result indicated that the phthalazinone derivative 2 exists in the tautomer form 2a not 2b (Chart 1).…”

“…White crystals; yield (2.6 g, 85%); mp 184-186°C (Lit., 31) All experiments were performed three times. The data are expressed as the mean±standard error of the mean (S.E.M.).…”

Design, Regiospecific Green Synthesis, Chemical Computational Analysis, and Antimicrobial Evaluation of Novel Phthalazine Heterocycles

“…N ‐Heterocycles are one of the most important bioactive molecules that were found to have wide applicability . Benz‐fused pyridazines have gained extensive interest because of their exciting biological properties and have been proven to display appreciable broad spectrum in natural compounds . It also acts as a center structure for different bioactive molecules because of its easy fictionalization at different substitution patterns and their roles as pharmacophore .…”

An Efficient Synthesis of Novel Bioactive Thiazolyl-Phthalazinediones under Ultrasound Irradiation

“…Moreover, the bicyclic phthalazine skeleton has been proven to display appreciable broad spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria as well as fungi [ 14 ]. In a recent study [ 15 ], various phthalazine derivatives bearing aliphatic, aryl, and heteroaryl side chains at the C2 position of the phthalazine skeleton exhibited potent antimicrobial effects.…”