Quinolone analogues 7 [1-6]. Synthesis of 3-Heteroaryl-1-methylpyridazino[3,4-b]quinoxalin-4(1H)-ones

Abstract

The 3-heteroaryl-1-methylpyridazino [3,4-b]quinoxalin-4(1H)-ones 6a-e were synthesized by the oxidative-hydrolytic ring transformation of the 3-heteroaryl-1,2-diazepino[3,4-b]]quinoxaline-5-carbonitriles 9a-c, which were obtained by the 1,3-dipolar cycloaddition reaction of the 2-(2-heteroarylmethylene-1-methylhydrazino)quinoxaline 4-oxides with 2-chloroacrylonitrile. The assignment of the thiophene and furan ring protons was carried out through the data of the NOE, decoupling, and coupling constants.

Quinolone Analogues 12: Synthesis and Tautomers of 2‐Substituted 4‐Quinolones and Related Compounds

“…In previous articles , we reported the synthesis of the 1‐methylpyridazino[3,4‐ b ]quinoxalines 1a , 1b , 1c , 1d , 1e , 1f , 1g , 1h as candidates of antibacterial quinolone analogues (Chart ). The 3‐alkyl 1c , 1d , 1e , 3‐H 1f , and 3‐halogeno 1g , 1h derivatives were found to have antifungal and/or antibacterial activities ,, whereas the 3‐amino 1i , 1j and 3‐heteroaryl 1k , 1l , 1m derivatives were clarified to possess no antibacterial and antifungal activities .…”

Quinolone Analogs 13: Synthesis of Novel 1,1′‐(2‐Methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) and Related Compounds

“…In previous papers , we reported the synthesis and biological activities of the 1‐alkyl‐4‐oxopyridazino[3,4‐ b ]quinoxalines 1 as candidates of antibacterial quinolone analogs (Chart ), some of which showed good antibacterial, antifungal, and/or algicidal activities . To search for biologically active compounds, we have then changed the target ring system from 4‐oxopyridazino[3,4‐ b ]quinoxaline to 4‐oxoquinoline such as quinolone antibacterials.…”

Quinolone analogs 11: Synthesis of novel 4‐quinolone‐3‐carbohydrazide derivatives with antimalarial activity

“…In previous papers [1–9], we reported the synthesis of the 1‐alkyl‐4‐oxopyridazino[3,4‐ b ]quinoxalines 1 (Chart 1) as candidates of antibacterial quinolone analogs [1–10], which were found to have antibacterial, antifungal, and/or algicidal activities [3–6]. Thereafter, we changed the target ring system from the pyridazino[3,4‐ b ]quinoxalin‐4(1 H )‐one to 4‐quinolone such as new quinolones 2 to search for novel biologically active compounds.…”