Benzo -2,7-naphthyridine, preparation

In a sequence analogous to the Suzuki reaction and annulation described in section 4.2.4, pyridine-containing tricyclic compounds have also been prepared via the Stille reaction and a subsequent annulation [80, 81]. For instance, benzo[c]-2,7-naphthyridine 94 was assembled from the adduct of 3-formyl-4-(trimethylstannyl)pyridine (93) and 2-bromo-4-methoxyacetanilide. The reaction was facilitated by addition of CuO as the co-catalyst. 

The two benzo-l,8-naphthyridines (89 and 90) have been prepared by treatment of iV-(p-chlorophenyl)-2-aminonicotinic acid and JV,iVr -bis(2-oxohexahydrobenzoyl)-2,6-diaminopyridine, respectively, with sulfuric acid.120 121... 

The benzo[6]2,6-naphthyridine derivative (95) prepared from compound 94 has been converted into the benzo-2,6-naphthyridine-trione (96).122 Aside from a few derivatives of this isomer, prepared in... 

An essentially similar type of reaction has been used to prepare fused 1,5-naphthyridines such as 2,8-dimethyl-6,12-bis(p-tolylimino)-5,6,ll,12-tetrahydrodi-benzo[ >, g][l,5]-naphthyridine (3).688... 

Benzo[6][l,3]benzodioxolo[5,6-/ ][2,6]naphthyridine was prepared via a multistep synthetic sequence starting from 3,4-dimethoxyacetanilide, 1,3-benzodioxol-5-amine, benzaldehyde and MeCOCH=CH2. This naphthyridine was assayed for inhibiting cell growth against a number of human cancer cell lines, such as RPMI 8402, CPT-K5 and U 937 (2003PIAW02003051289). 

Ethyl (2-chloroquinolyl-3-carbonyl)acetates 193 served as the starting compounds for the preparation of benzo[fi][l,8]naphthyridines 194-196 (1991FRP2642070, 1991FRP2642071) possessing high antibacterial activity against Gram-positive bacteria. These compounds are used for the treatment of skin staphylococcus infections and water purification and also as preservatives and decontaminants. 

Dehydrogenation of 5,6-dihydro derivatives of 2,7-naphthyridines 339, prepared by the addition of organolithium compounds to 4-substituted benzo[c][2,7]nap-hthyridines 340, afforded naphthyridines 341 (1995JCS(P1)979). 

The reaction between o-bromoaniline and 2-formylbenzeneboronic acid by the coupling procedure provides a new method for the preparation of phenanthridine. Applied to 2-amino-3-bromopyridines aza analogs are formed, as exemplified by the benzo[c][l,8]naphthyridine (232). Isomeric o-formylthiopheneboronic acids yield the corresponding thienylpyridines,... 

In the past year, reviews on 1,8-naphthyridines, perimidines, polyazaphen-anthrenes, 3-azabicyclo[3.3.1]nonanes, and 1,2- and 2,1-benzothiazines have appeared. Reviews on specialist aspects of pyridine chemistry are devoted to the reactions of newly available pyridines, a,a -disubstituted pyridines, the reactions of pyridines with nucleophiles, the electrochemistry of IjT-disubstituted 4,4 -bipyridinium ions (the viologens such as paraquat), dihydropyridines, and 4-aryl-dihydropyridines (a new class of calcium antagonists). Reviews have been published on the cyclization of oximes and amides to quinolines and isoquinolines, quinoline- and isoquinoline-diones, benzo[fl ]- and benzo[c]-quinolizinium ions, azachrysene preparation, quinazolines with plant-growth-regulating and biocidal activities, quinazolines in pharmaceutical research, isotopic hydrogen exchange in... 

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