Sakae Takaku

Reactions of 3-substituted quinoline 1-oxides with acylating agents

Reactions of 3-fluoro- (1a), 3-bromo- (1b), 3-methyl- (1c), 3-methoxy- (1d) and 3-acetamidoquinoline 1-oxides (1e) with acylating agents (POCl 3 , Ac 2 O, TsCl and PhCOCl) were examined (table). While only 2-substituted quinolines were obtained from 1a and 1b, fair amounts of 4-substituted products were formed in reactions of 1d, the sole formation of the 4-acetoxyquinoline (6) with Ac 2 O being the most significant result. 2-Chloroquinoline, 4-chloroquinolines and 2-tosyloxyquinolines were formed (and sometimes predominate) in addition to 2-quinolinones in reactions with TsCl

New cyclization reactions of 3-dialkylamino-4-amino-pyridines under conditions of nitration

Treatment of 3-dialkylamino-4-aminopyridines (1) with nitric and sulfuric acids affords imidazo-[4,5-c] pyridine derivatives (2, 3 and 4) and 1,2,3- triazolo [4,5-c] pyridine 2-oxides (5) by cyclization reaction of the corresponding 4-nitroaminopyridines

Synthesis of 2,3-Fused Quinolines from 3-Substituted Quinoline 1-Oxides. Part III. Intramolecular Cyclization of Quinoline 1-Oxides Bearing Active Methylene Groups at the 3-Position in the Presence of Acetic Anhydride

3-N-Alkylcyanoacetamidoquinoline 1-oxides (3a and 3c) react with Ac 2 O at room temperature in chloroform to afford 1-alkyl-3-cyano-4H-pyrrolo [3,2-b]quinolin-2-ones (4a and 4c). The cyclization of 3-N- alkylethoxycarbonylacetamidoquinoline 1-oxides (3b and 3d) occurs upon heating with Ac 2 O at 60°C. 3-(3,3-Dicyanopropoxy)quinoline 1-oxide (5) also cyclizes to the pyranoquinoline (6) when treated with Ac 2 O at room temperature in chloroform-DMF

Reinvestigation of the Reaction of 3-Bromo-4-nitroquinoline 1-Oxide with 1-Morpholinocyclohexene

Reinvestigation of the reaction of 3-bromo-4-nitroquinoline 1-oxide (2) with 1-morpholinocyclohexene (3) has revealed that the reaction proceeds by a multistep ionic process involving the initial formation of 3-morpholino-4-nitro-2-(2-oxocyclohexyl)quinoline (6) and the subsequent transformation of 6 into 10-nitro-1,2,3,4-tetrahydrobenzofuro[3,2-b]quinoline (5). Not only 2 reacts with various enamines in the same way, but also 3-bromo-4-nitropyridine N-oxide (7) undergoes the same type of reaction.