3-Phenyl-5,6-dihydro-1 //,7//-pyrido

Zur reduzierenden Acetylierung von 3-Phenyl-bzw. 2,3-Diphenyl- pyrido-[2,3-b]-py-razin) in Acetonitril/Acetanhydrid zu 2-Phenyl-1,4-diacetyl-1,4-dihydro- (25% d.Th.) bzw. 2,3-Diphenyl-5-acetyl-5,8-dihydro-(pyrido[2,3-b]-pyrazin) (91% d.Th.) s. Lit.2 ... 

Stmctures of 3-hydroxy-3-phenyl-3,4-dihydro-l/7- <2006JST(792)36>, l-hydroxy-l-methyl-3-phenyl-17/-pyrido[2,l-c]-... 

Bei dieser Reaktion konnen allerdings auch Kohlensaure-bis-hydrazide entstehen. So cyclisiert l-Amino-2-oxo-4,6-diphenyl-l,2-dihydro-pyridin mit Kohlensaure-bis-imidazolid zu 5,7-Di-phenyl-(pyridio[2,l-b]-l,3,4-oxadiazolium )-2-olat innvA 37%iger AusbeutelS0(vgl. S. 533, 535). AuBerdem wird 1,3-Bis-[4,6-diphenyl-2-oxo-l, 2-dihydro-pyrido -harnstoff (45%) gebildet. 

Phenyl-2//-pyrido 2,3-<7 [l,3]oxazine-2,4(l//)-dione (64) with diethyl malo-nate gave ethyl 4-hydroxy-2-oxo-l-phenyl-l,2-dihydro-l,8-naphthyridine-3-carboxylate (65) (reactants, NaH, 150°C 85%) 453,407 the same substrate (64) with ethyl nitroacetate gave 4-hydroxy-3-nitro-l-phenyl-1,8-naphthyr-idin-2(lfl)-one (66) (NaH/MeCONMe2, 100°C 77%).1191... 

The analogous 1,3-dihydro-l-methyl-5-phenyl-2//-pyrido(4,3-e)-l,4-diazepin-2-one (206) as well as the three other isomeric pyrido-diazepinones and the corresponding intermediates have been prepared.219... 

Treatment of 4-phenyl-2,3-dihydro-l//-pyrido[l,2-c]pyrimidine-l,3-dione with POCI3 in the presence of iV,N-dimethylaniline gave 3-chloro-4-phenyl-l//-pyrido[l,2-c]pyrimidin-l-one. The 3-chloro atom could be substituted by amino and alkoxy groups. Treatment of the 3-chloro derivative with thiourea afforded 4-phenyl-3-thioxo-2,3-dihydro-l//-pyrido[l,2-c]pyrimidin-l-one (57HCA1319). 

Heating 6-bromo- and 6-chloro-2-halomethyl- (99JHC1065) and 6-bromo-, 6-chloro- and 6-fluoro-2-phenyl-47y-pyrido[l,2-a]pyrimidin-4-ones (00JMC2814) in phenyl ether at 220 °C for 10 min yielded the appropriate 7-halo-1,8-naphthyridin-4-ols. 6-Amino-2-trifluoromethyl-477-pyrido[ 1,2-a]-pyrimidin-4-one was transformed into 7-amino-2-trifluoromethyl-1,4-dihydro-l,8-naphthyridin-4-one in 90% yield (98EJM383). 

Cyclization of 3-cyano-2-[(3-hydroxypropyl)amino]-5-(4-pyridyl)pyri-dine-l -oxide (298) in POCI3 yielded 9-cyano-7-(4-pyridyl)-3,4-dihydro-2/f-pyrido[],2-n]-pyrimidine I -oxide (299) (94EJM175). After heating 3-cyano-4-trifluoromethyl-6-phenyl-2-[(3-hydroxypropyl- and 3-hydroxybutyl)-amino] pyridines in boiling POCI3 for 1 h, the product was treated with aqueous NH4OH to yield 6-phenyl-8-trifluoromethyl-9-cyano-3,4-dihydro-2//-pyr-ido-[l,2-n]pyrimidine and its 4-methyl derivative (01CHE329). 

Phenyl-5,6-dihydro-l//,7//-pyrido[3,2,l-//]quinazoline-7-one and 1,7-dione 179 (X = H2 and O) were prepared from tetrahydroquinolines 206 and 207 with A-(ethoxycarbonyl)thiobenzamide and PhCOCl, respectively (98EJM763). 

Hydrazone of 1 -hydrazino-1 -hydroxy-4-phenyl-1,2-dihydro-3//-pyrido [l,2-c]pyrimidin-3-one was patented as cross-linkers for making physiologically compatible and H2O insoluble hydrazine or hydrazono compounds (97JAP(K)97/59303). 

The crystal structures of 4-phenyl-2- 4-[4-(2-pyrimidinyl)piperazin-l-yl]butyl -2,3,5,6,7,8-hexahydro-177-pyrido[l,2-c][l,3]oxazine-l,3-dione <1995ZK899>, 4-cyano-l-phenyl-l-trifluoromethyl-2,3-dihydro-l/7-pyrido[l,2-r-]pyrimidin-... 

Tetrahydropyrido[2,1 -HI 1,4 oxazinc-7,9-dicarboxylate 278 was obtained from the 1,8-dihydro derivative 277 by hydrogenation over a Pd/C catalyst (Equation 51) <1997CAP2188071 >. Catalytic hydrogenation of an epimeric mixture of (4.S, 9a.S )-l -trimcthylsilyloxy-4-phenyl-3,4,6,7-tetrahydro-l//-pyrido[2,1 -HIl,4]oxazine over Raney-Ni afforded perhydro derivatives <2000SC2565>. 

Thermolysis of 3-alkyloxy- and 3-aroyloxy-5-phenyl-l,2,4-pyrrolo[l,2- ]quinoxaline-l,2,4-triones afforded 5-phenyl-9-(4-phenyl-3-oxo-3,4-dihydro-2-quinoxalinyl)-6,8,10-trioxo-5,6,9,10-tetrahydro-87/-pyrido[l,2-tf ]quinoxaline-7,9-dicarboxylates <2000CHE615, 2004CHE1295> and 7-aroyl-8-aroyloxy-5-phenyl-9-(4-phenyl-3-oxo-3,4-dihydro-2-quinoxalinyl)-5,6-dihydro-1077-pyrido[l,2- ]quinoxaline-6,10-diones <2002CHE498>, respectively. Thermolysis of 3-aryl-2-(5-aryl-2,3-dioxo-2,3-dioxo-4-furanyl)quinoxalines gave 7-aroyl-8-aroyloxy-6-aryl-9-(3-aryl-2-quinoxalyl)-10/7-pyrido[l,2- ]quinoxalin-10-ones <2001CHE1314, 2002RCB850>. 

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