2.3.6.7- Tetrahydro-177,5/7-pyrido quinazoline-1,3-diones

Ozonolysis of 6-(phenylmethylene)-6,7,8,9-tetrahydro-l l//-pyrido[2,l-fi]-quinazolin-11-one in CH2CI2 gave 6,7,8,9-tetrahydro-l l//-pyrido[2,l-fi]-quinazoline-6,11-dione (01H(55)1555). 

Reaction of 1 -methylene-1,2,3,4-tetrahydro-5//-pyrazino[2,1 -Z)]quina-zoline-3,6-diones (435) with PhLi and MeMgBr in THE at —78°C gave a mixture of 1 l//-pyrido[2,l-Z)]-quinazolin-l 1-ones 435-439 (01T1987). 

Reduction of 2,3,6,7-tetrahydro-177,5i/-pyrido[3,2,l-//]quinazoline-l,3,7-trione and 7-chloro-6-formyl-2,3-dihydro-177,5i/-pyrido[3,2,1 -(/]quinazo-line-l,3-dione with NaBH4 in THF in the presence of 60% aqueous solution of NaOH gave 7-hydroxy and 7-chloro-6-hydroxymethyl derivatives, respectively (01MI28). 

Vilsmeyer-Haack formylation of 7-hydroxy-2,3,6,7-tetrahydro-l//,5//-pyrido[3,2,l-y]quinazoline-l,3-dione with POCI3/DMF gave 7-chloro-6-formyl-2,3-dihydro-l//,5// derivative. Boiling a toluene solution of the aforementioned 7-hydroxy derivative in the presence of pTSA yielded dehydrated 2,3-dihydro derivative (01MI28). 

Tetrahydro-l//,5//-pyrido[3,2,l-//]quinazoline-l,3-diones were prepared by the cyclization of l-tert-butoxycarbonyl-l,2,3,4-tetrahydroqui-noline-8-carboxamide on the action of 60% aqueous NaOH solution in THF at 50 °C (01M128). 

Hexahydro-1/Lf-pyrimido[5/6/1-/fcJl1,4Jbenzdiazepine-1/8-one 86 was obtained when NaN3 was gradually added to a solution of 2,3/5,6-tetrahydro-lH,7H-pyrido[3,2,Hy]quinazoline-l,7-dione 85 in MeS03H (06USA2006 /0004028). 

Reaction of methyl 5-fluoro-l,2,3,4-tetrahydroquinoline-8-carboxylate and (3-Cl-Ph)NCO in PhMe at 90 °C for 20 h afforded 2-(3-chlorophenyl)-8-fluoro-2,3,6,7-tetrahydro-l H,5H-pyrido [3,2,1 -ij] quinazoline-1,3-dione in 35% yield (07WOP2007/028789). 

Reaction of 5-bromo-l,2,3,4-tetrahydroquinoline-8-carboxylic acid with COCl2 in THF at room temperature for 16 h gave 8-bromo-6,7-dihy-dro-lH,3H,5H-pyrido[3,2,l-//J[3,lJbenzoxazine-l,3-dione in 80% yield (07WOP2007/028789). 8-Bromo-2-aryl-2,3,6,7-tetrahydro-lH,5H-pyrido [3,2,1-zy]quinazoline-l,3-diones were also prepared in the reaction of N-aryl-5-bromo-l, 2,3,4-tetrahydroquinoline-8-carboxamides and ClC02Ph in boiling 1,2-dichloroethane for 30 min. 

Reaction of 6,7,8,9-tetrahydro-l 17/-pyrido[2,l-6]quinazoline-6,ll-dione and PhNHNH2 in EtOH afforded 6-phenylhydrazono derivative... 

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