3- Hydroxy-3,4,6,7-tetrahydro-2//pyrimido isoquinolines

Fluorophenyl)-l ]-hydroxy-2,3,4,1 ]-tetrahydro-6/7-pyrimido[],2-Z)]-isoquinolin-6-one was obtained in the reaction of l-(4-fluorophenyl)-3-oxo-],3-dihydro-2-benzofuran-l-carboxamide and 1,3-diaminopropane in boiling toluene (01BMCL339). 

The structures of ethyl 2-hydroxy-4-oxo-4//-pyrimido[2,l-a]isoquinoline-3-carboxylate (20) (89AJC2161), 6-[2-(4-methyl-l-piperazinyl)acetamido]-ll//-pyrido[2,l-b]quinazolin-ll-one (89JHC1229), and 6,7,8,9-tetrahydro-ll//-pyrido[2,l-b]quinazolin-ll-one (95KPS410) were determined by X-ray crystallography. 

Catalytic hydrogenation of 3,4-dihydro-2//-pyrimido[2,l-a]isoquinoline-2,4-diones (93) and 3,3-diethyl-9,10-dimethoxy-3,4,6,7-tetrahydro-2//-pyrimido[2,l-a]isoquinoline-2,4-dione (94) over Pt02 and Pd/C catalysts gave l,3,4,6,7,llb-hexahydro-2/7-pyrimido[2,l-a]isoquinoline-2,4-diones (95) [69YZ649 71JPP71/09466]. From the mother liquid of compounds 93 (R = H, R1 = Et and R = R1 = Et) 3-ethyl-2-hydroxy-6,7-dihydro-and -8,9,10,1 l-tetrahydro-4//-pyrimido[2,l-a]isoquinolin-4-ones, and 3,3-diethyl-l,3,4,llb-tetrahydro-2//-pyrimido[2,l-a]isoquinoline-2,4-dione, also could be isolated as minor products. Reduction of 3,3-diethyl-l,3,4,6,7,llfo-hexahydro-2//-pyrimido[2,l-a]isoquinoline-2,4-dione (95, R = R1 = Et, R2 = H) with LAH in tetrahydrofuran at 70°C for 9 h afforded 3,3-diethyl-l,3,4,6,7,llb-hexahydro-2//-pyrimido[2,l-a]isoquinoline (96). 

Treatment of 2-(2-methylphenyl)-5,5-dimethyl-l,4,5,6-tetrahydropyrimi-dine (279) with butyllithium in the presence of /V,/V,Al, /V -tetramethyleth-ylenediamine (TMEDA) in tetrahydrofuran at 0°C under nitrogen, then with methyl benzoates at -50°C gave 6-aryl-6-hydroxy-3,4,6,7-tetrahydro-2//-pyrimido[2,l-a]isoquinolines (280), which gave 6-ary 1-3,4-di hydro-2//-pyrimido[2,l-a]isoquinolines (281) with heating in toluene in the presence of p-toluenesulfonic acid (93JMC3098). 

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