Research on naphthyridines

4-Arylamino-6-methyl-5,6,7,8-tetrahydro-2,3-benzo-1,6-naphthyridines are obtained from N-(1-methyl-4-piperidylidene)anthranilic acid arylamides.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1393–1395, October, 1973.     

Investigation of naphthyridines

The corresponding arylamides were obtained from methyl 2-anilinonicotinate and dimagnesylamines, and the amides were converted to 4-arylamino-2,3-benzo-1,8-naphthyridines by the action of phosphorus oxychloride. The pK_a values of the 2-anilinonicotinic acid arylamides were determined.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–248, February, 1974.     

Investigation of naphthyridines

2-Acetyl-10-aryl-1,2,3,4-tetrahydrobenzo[b]-1,6-naphthyridines were obtained by reaction of 4-(2)-R-2-aminobenzophenones with 1-acetyl-4-piperidone, and their pK_a values were determined. It was found that they are oxidized by hydrogen peroxide to give the corresponding N-oxides in good yields. The N-oxides are converted to the 4-acetoxy derivatives by the action of acetic anhydride.See [1] for communication VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1383–1385, October, 1976.     

Investigation of naphthyridines

A method for the synthesis of 9-amino-4-azaacridines by cyclization of 2-arylaminonicotinonitriles by heating with aluminum chloride is proposed. The 2-arylaminonicotinonitriles were obtained by condensation of 2-chloronicotinonitrile with arylamines.     

A study of naphthyridines

4,4-Diaryl-1,4-dihydro-2,3-benzo-1,8-naphthyridines have been synthesized by the cyclization of diaryl 2-arylaminopyridin-3-yl carbinols. The latter were obtained by the reaction of methyl 2-arylaminonicotinates with arylmagnesium halides. With acid chlorides, the 4,4-diaryl-1, 4-dihydro-2,3-benzo-1,8-naphthyridines form 1-acyl derivatives. The pK_a values of the 4,4-diaryl-1,4-dihydro-2,3-benzo-1,8-naphthyridines in nitrobenzene have been determined, and a correlation has been found of the pK _a values with the ^* constants of the substituents (r=0.955, ^*= –1.53, pK _a ^° calc=2.51, s=0.01).For Communication II, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 119–121, January, 1974.     

Mono-N-amino salt of benzodiazines and naphthyridines

The mono-N-amino salts of 3-phenylcinnoline, phthalazine, 1-phenylphthalazine, 4-phenylquinazoline, 2-phenylquinoxaline, 1,5- and 1,8-naphthyridines are in high yields prepared by direct N-amination of the parent heterocycles with O-mesitylenesulfonylhydroxylamine. With the one expection of 3-phenylcinnoline, the site of N-amination was determined by mass and nmr spectral techniques. The results indicate that the N-amination occurs preferentially at the least sterically hindered nitrogen atom.     

Synthesis of novel benzo naphtho naphthyridines from 2,4-dicloroquinolines

A schematic study on the condensation of 2,4-dichloroquinolines ( 1 ) with 1-naphthyamine ( 2 ) in the presence of CuI as a catalyst to functionalized mono ( 3 ) and di ( 4 ) substituted naphthylamino quinolines was described. Consequently, these mono- and di-substituted amines on polyphosphoric acid-catalyzed cyclization reaction with p-toluic acid and acetic acid to yield the linear benzo[b]naphtho[2,1-g][1,8]naphthyridines ( 5 ) and angular benzo[b]naphtho[2,1-h] naphthyridines ( 6 ) in good yields. In addition to descried the similar synthesis of benzo[g]naphtho [2,1-b][1,8]naphthyridines ( 12 ) and benzo[h]naphtho[2,1-g][1,8]naphthyridines ( 13 ) from 2,4-dichlorobenzo[h]quinoline ( 8 ) with various anilines ( 9 ) through my intermediates ( 10 and 11 ).     

Preparation of benzo[c][2,7]naphthyridines

A divergent synthesis of substituted benzo[c][2,7]naphthyridines 5a-h is described, which features an intramolecular pyridyne cyclization step as the key reaction. The pyridyne precursors are conveniently prepared from the pyridinium hydrochloride 2 and the requisite anilines. Cyclization of the non-symmetric substrates 3e and 3f did not proceed with significant regioselectivity.     

Synthesis and reactions of naphthyridines (review)

Methods for the preparation of 1,5-, 1,6-, 1,7-, and 1,8-naphthyridines and their chemical properties are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 3–16, January, 1979.     

New domino heteroannulation of enaminones: synthesis of diverse fused naphthyridines

A series of new poly-functionalized fused naphthyridine derivatives were synthesized via a three-component reaction of aldehyde, 2-aminoprop-1-ene-1,1,3-tricarbonitrile and enaminone in EtOH using EtONa as a base. During these reaction processes, the domino construction of fused naphthyridine skeleton with concomitant formation of two new pyridine rings was readily achieved via base promoted three-component reactions in a one-pot operation. The procedures are facile, avoiding time-consuming and costly syntheses, tedious work-up and purifications of precursors.     

Diazepines and naphthyridines from the rearrangement of thienoindolizidinone oximes

Thienoindolizidinone oximes previously reported [1] were treated with polyphosphoric acid and led to thienopyrrolidinodiazepines or thienonaphthyridines. The rearrangement depends on the structural form of the starting oxime and the results obtained are discussed.     

Synthesis of isoquinolines and naphthyridines by electrophilic ring closure of iminoalkynes

Substituted isoquinolines and naphthyridines have been prepared in good to excellent yields by the reaction of iminoalkynes with a variety of electrophiles under mild reaction conditions. Reaction: see text.     

Synthesis of 5-amino-1,2,3,4-tetrahydrobenzo[b][1,7]naphthyridines and 2,3,4,4a,5,6-hexahydrobenzo[c][2,6]naphthyridines

This paper describes the synthesis of some 5-amino-1,2,3,4-tetrahydrobenzo[b][1,7]naphthyridines and 2,3,4,4a,5,6-hexahydrobenzo[c][2,6] naphthyridines starting from anilines and 1-benzyl-4-ethoxycarbonylpiperidin-3-one. The compounds were prepared in order to study their potential acetylcholinesterase inhibitory activity.     

6H-indolo [3,2-b] naphthyridines.aza-analogues of ellipticine

The Friedlander quinoline synthesis is applied to prepare new potential DNA - intercalative compounds : The 6H-indolo [3,2-b] naphthyridines.     

Regioselective homolytic substitution of benzo[c][2,7]naphthyridines

Benzo[c][2,7]naphthyridines bearing electron-withdrawing substituents (bromo, acetyl) at C-4 undergo regioselective homolytic substitutions at C-5 with nucleophilic 1,3,5-trioxanyl and ethoxycarbonyl radicals under Minisci conditions. Surprisingly, mainly 5,6-dihydro derivatives are formed in these reactions. Rearomatization with manganese dioxide leads to 4,5-disubstituted benzo[c][2,7]naphthyridines, which should be attractive building blocks for the synthesis of pyridoacridine alkaloids. Homolytic methylation at C-5 takes place with methyl radicals generated from acetic acid and acetaldehyde, respectively.     

Research on naphthyridines. 10. Synthesis and ionization constants of 10-alkylaminobenzo[b]-1,8-naphthyridines

10-Alkylaminobenzo[b]-1,8-naphthyridines were synthesized by cyclization of 2-arylaminonicotinic acid alkylamides by means of phosphorus oxychloride. The pK_al values of the 10-alkylaminobenzo[b]-1,8-naphthyridines, which range from 8.74 to 8.50, were determined by potentiometric titration in anhydrous ethanol.See [1] for communication 9.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 799–801, June, 1979.     

Facile Synthesis of 1-Hydroxy-5-methoxy-Benzo[f][2,7]naphthyridines

A new route for the synthesis of 1-hydroxy-5-methoxy-benzo[f][2,7]naphthyridines has been developed from easily available precursor 2-chloro-3-formyl quinolines. The 2-methoxy-3-formyl quinolines were prepared and condensed with glycine ethyl ester hydrochloride. This resulted in the formation of an imines, which on cyclization with Dowtherm A yielded 1-hydroxy-5-methoxy-1,2-dihydrobenzo[f][2,7]naphthyridines.