Benzo naphthyridine

Benzonaphthyridines, 2, 581-627 nomenclature, 2, 612 synthesis, 2, 612 Benzo-1,5-naphthyridines biological activity, 2, 625 Benzo[/i][ 1,5]naphthyridines photoelectron spectra, 2, 585 Benzo[/i][l, 6]naphthyridines photoelectron spectra, 2, 585 synthesis, 2, 613 Benzo[/][l, 7]naphthyridines photoelectron spectra, 2, 585 synthesis, 2, 613 Benzo-1,8-naphthyridines synthesis, 2, 608... 

Benzo[6][l,8]naphthyridines — see 1,9-Diazaanthracenes Benzo[/][2,7]naphthyridines occurrence, 2, 626 Benzonitrile... 

JHC961). When 2,7-naphthyridine (192) was brominated, a mixture of 4-bromo and 4,5-dibromo products was formed (70JHC419). In basic medium bromine converted benzo[6][l,8]naphthyridine-9-carboxaldehyde into the 3,7-dibromo-9-carboxylic acid (92JHC1197). 

Treatment of benzo[c][l,5]naphthyridine with dichlorocarbene, formed from the thermal decomposition of sodium trichloroacetate, gives the corresponding iV-dichloromethylide, 1,3-dipolar cycloaddition of which with DMAD, with loss of HC1, gives the corresponding pyrrolonaphthyridine 284 (Equation 98) <1995M227>. In the [1,6]- and [1,7]-naphthyridine series, compounds 285 and 286 are obtained by the same route and in the [l,8]naphthyridine series compound 287 is obtained from the parent naphthyridine, dichlorocarbene, and dimethyl maleate followed by oxidation (Equation 99) <1998RJ0712>. 

Quaternization of benzo[/][l,7]naphthyridine with halogenoacyl halides occurs at N-7, and the quaternary salts may then be deprotonated to give the ylides. These ylides can then react with a variety of dienophiles to give the corresponding pyrrolonaphthyridines (Scheme 72) <1996PJC1324, 1999AJC149>. 

The benzo-fused dihydrotetrazolo[2,7]naphthyridine 308 is a minor end-product of a mixed Hantzsch pyridine synthesis involving 2-azido-3-nitrobenzaldehyde, /3-aminocrotononi trile, and methyl /3-aminocrotonate in ethanol (Scheme 76) <2001TL4507>. 

Under conventional heating the rearrangement [21] of pyrrolo-[2,l-c]-benzodiaze-pine, 45, in boiling phosphorus oxychloride, into benzo-[h][l,6]-naphthyridine 46 required a long reaction time (5 h) (Scheme 8.16). 

In terms of structural classes, Mitscher described seven cores that fall under the quinolonefamily, as shown below in Figure 4.1 (Mitscher, 2005). Of these cores, three templates have produced the most commercially successful drugs. They include the 4-0X0-1,4-dihydroquinolone (5), 7-oxo-2,3-dihydro-7H-pyrido-[l,2,3-d,e]-l,4-benzo-xazine (6), and the 4-oxo-l,4-dUiydro-[l,8]-naphthyridine cores (7). 

The possibility of regioselective angular fusion has been demonstrated in the annelation of two benzo[ ][l,8]naphthyridine units on to a 1,8-naphthyridine nucleus, leading to three isomeric octacyclic compounds (79JOC531). The condensation between two molecules of 2-aminonicotinaldehyde, two of cyclohexane-1,3-dione and one of 4-aminopyrimidine-5-carbaldehyde gave a mixture of the three isomeric products (420), (421) and (422). 

The alkaloids of perennial rye grass, perloline (438) and perlolidine (302), have been shown to be benzo[/][2,7]naphthyridine derivatives <66JCS(B)454), whilst degradation of calycanthine (439) affords calycanine or dibenzo[c,fc][2,6]naphthyridine (356), the structure of which was proven by an unequivocal synthesis from leucoisoindigo (60MI21100). A number... 

Thermal isomerization of l//-pyrimido[l,2-a]quinolin-l-ones (185) into benzo(6)-l,8-napthyridin-4(li/)-ones (186) (94AJC1263), did not occur whereas 6-substituted 4//-pyrido[l,2-a]pyrimidin-4-ones gave 1,8-naphthyridin-4( l//)-ones [77JCS(P1)789]. 

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 electron-impact-induced fragmentations of two dibenzo[6,/]-1,6-naphthyridines,50 several benzo[/]l,7-naphthyridines,45 and some perhydro tricyclic homologs of 1,6- and 2,7-naphthyridine51 follow expected breakdown pathways. 

Aminoquinoline has been reported 68 to give the linear benzo-1,5-naphthyridine (20), Buii-Hoi and co-workers69 have contested this... 

The EMME synthesis with 3-aminoquinoline was incorrectly described as yielding the linear compound 24. Later workers45,74 showed that the product was the angular benzo-l,7-naphthyridine (25). 

The similar condensation of 3-aminoquinoline with EMME to give benzo-l,7-naphthyridines has been described earlier (see Section HI. A). 

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 interesting amination, apparently involving displacement of a phenyl group in the benzo[c]l,7-naphthyridine (132)147 has been reported. 

This, the eleventh volume of Advances in Heterocyclic Chemistry, includes surveys of the chemistry of the following groups of heterocyclic compounds benzo[6]thiophenes (B. Iddon and ft. M. Scrow-ston), naphthyridines (W. W. Paudler and T. J. Kress), and quinu-clidines (L, N. Yakhontov). In addition, R. A. Jones covers the application of physical methods to pyrrole chemistry and a very topical subject, the photochemistry of heterocycles, is reviewed by S. T. Reid. 

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