1.8- Naphthyridine-3-carboxylate

Heating diethyl (2-pyridylamino)methylenemalonates 304 (R = COOEt, = Me, OH) in AcOH afforded 4-oxo-4//-pyrido[l, 2-n]pyrimidine-3-carboxylates 305 (R = Me, OH) (96JHC1041). Flash vacuum thermolysis of 2-substituted 3-(2-pyridylamino)acrylates 304 (R = CN, COOEt, R = H) through a packed silica tube (530 °C, 0.01 mmHg) gave 3-substituted 4//-pyrido[l,2-n]pyrimidm-4-ones 306 (R = CN, COOEt) (94AJC1263). Ethyl 7-methyl-4-oxo-l, 4-dihydro-1,8-naphthyridine-3-carboxylate (79%) was... [Pg.234]

Chemical Name 1-ethYl-1,4-dihYdro-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylic acid Common Name —... [Pg.1051]

CN l-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-( 1 -piperazinyl)-1,8-naphthyridine-3-carboxylic acid... [Pg.743]

The cyclization of diethyl iV-substituted N-(6-alkyl-2-pyridyl)amino-methylenemalonates (265, R2 = Et) in polyphosphoric acid at 200-230°C for 10 min gave 1-substituted 7-alkyl- 1,4-dihydro-1,8-naphthyridine-3-carboxylic acids (1022, R = Me, Et R1 = alkyl R2 = H) in 17-56% yields (71GEP2108046). From the mother liquor, 2-(substituted amino)-6-alkylpyridines could be recovered. [Pg.223]

Cyclopropyl-1,4-dihydro-1,8-naphthyridine-3-carboxylate (1025) was prepared in 43-48% yields by the cyclization of jV-cyclopropyl-M-[6-(4 - ethoxycarbonyl -1 - piperazinyl) -5- fluoro -2-pyridyl ] aminomethylene -malonate (111) in acetic acid by the action of concentrated sulfuric acid at 55-60°C for 1 hr (85EUP153163, 85EUP153828, 85EUP159174 86EUP172651 88EUP265230). [Pg.224]

Isopropylidene 7V-cyclopropyl-Af-[6-(4-ethoxycarbonylpiperazin-1 -yl)-5-fluoropyridin-2-yl]aminomethylenemalonate (428) was cyclized in a mixture of acetic anhydride and concentrated sulfuric acid at 50-60°C for 2 hr to give 1,8-naphthyridine-3-carboxylic acid (1198) in 68% yield (85EUP153163, 85EUP153828, 85EUP159174 86EUP172651 88EUP-265230). [Pg.256]

Ring transformation of the initial 6-substituted 4//-pyrido[l,2-a] pyrimidin-4-ones also occurred when 2-[(6-substituted 2-pyridyl)acrylates were heated in a high-boiling solvent. For example, heating diethyl [(4,6-dimethyl-2-pyridyl)amino]malonate in boiling diphenyl ether afforded ethyl 5,7-dimethyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate... [Pg.231]

Diethoxycarbonylvinylamino)-6-fluoro-7-methylpyridine (23) gave ethyl 6-fluoro-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (24) (Dowtherm, heat 80%) 1091 such a cyclization has also been done under... [Pg.186]

Ethyl 7-chloro-l-(2-hydroxyethyl)- (15, R=OH) gave ethyl 2-chloro-l-(2-chloroethyl)-4-oxo-l,4-dihydro-l,8-naphthyridine-3-carboxylate (15, R = Cl) (SOCl2, CHC13, reflux 70%) 1049 the analogous product, ethyl 7-chloro methyl-1 -ethyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (16) was made somewhat similarly (SOCl2, ZnCl2, CHC13 25°C 83%).1248... [Pg.212]

Ethyl 6-chloro-1 -ethyl-7-methoxy-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (2) gave 6-chloro-l-ethyl-4,7-dioxo-l,4,7,8-tetrahydro-l,8-naphthyridine-3-carboxylic acid (3) (1M NaOH, 95°C 95% note the additional saponification of the ester group).387... [Pg.222]

Chloro-1 -ethyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid (11, R = H) gave its ethyl ester (11, R = Et) (ClCC Et, Et3N, CHCI3 then EtOH 96%) 418 an analogous esterification used oxalyl chloride in the first stage. [Pg.250]

Aminopyrrolidin-1 -yl)-6-fluoro-4-oxo-1 -(thiazol-2-yl)-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid (13, R = OH) gave the corresponding 3-carboxamide (13, R = NH2) via the unisolated acid chloride (13, R = Cl) (ClC02Et, Et3N then NH3/EtOH 54%).352... [Pg.251]

Methyl 6-bromo-2-oxo-1,2,3,4-tetrahydro-1,8-naphthyridine-3-carboxylate (17, R = C02Me) gave 6-bromo-3,4-dihydro-l,8-naphthyridin-2( 1 //)-one (17, R = H) (NaOH, MeOH, H20, reflux then HC1 to pH 7, reflux 88%).194... [Pg.253]

Ethyl 6-amino-7-chloro-1 -ethyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (21, Q = C1, R = Et) gave 6-amino-1 -ethyl-iV-methyl-7-methylamino-4-oxo-1,4-dihydro-l,8-naphthyridine-3-carboxamide (21, Q = R = NHMe) (MeNH2/ EtOH, 60°C 95% note the additional aminolysis of the chloro substituent).1029... [Pg.253]

Oxo-7-trichloromethyl-1,4-dihydro-1,8 -naphthyridine-3 -carboxylic acid (25) gave 7-(/V-methylcarbamo i)-4-oxo-l, 4-dihydro-1,8-naphthyridine-3-carboxylic acid (26) (MeNH2/EtOH, 90°C, sealed 70%) also many analogs by slightly modified procedures.1012... [Pg.255]

Ethyl 7-chloro-l-cyclopropyl-6-fluoro-4-oxo-5-trimethylsilyl- (41, R=SiMe3) gave ethyl 7-chloro-1 -cyclopropyl-6-fluoro-5-formyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (41, R=CHO) (POCl3, Me2NCHO, o-C 12C6H4, 90°C 24%).1172... [Pg.258]

Amino-7-chloro-1 -ethyl-4-oxo-1,4-dihydro-1, 8-naphthyridine-3-carboxylic acid >300 1029... [Pg.369]

Amino-8-hydroxy-5-methyl-7-oxo-7, 8-dihydro-1,8-naphthyridine-3-carboxylic acid >320 748... [Pg.371]

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