2-Phenyl-2,3-dihydro-l//-pyrimido

Catalytic reduction of 4-benzyl-2-phenyl-2,3-dihydro-l//-pyrimido[6,l-fl]quinoline-l,3-dione with hydrogen over 5% Pt/C in acetic acid at 50°C for 15 h gave the 2,3,5,6,6a,7,8,9,10,10a-decahydro-l// derivative (83M227). 

Heating 4-benzyl-2-phenyl-2,3-dihydro-l//-pyrimido[l,6-a]quinoline-... 

The reaction of 2-(2-phenethyl)quinoline with 2 mol phenyl isocyanate at 180°C for 2 h gave 4-benzyl-2-phenyl-2,3-dihydro-17/-pyrimido[l,6-a] quinoline-1,3-dione (83M227). 

Benzyl-9-phenyl-3,4-dihydro-27/,677-pyrimido[6,l-A [l,3]thiazine-6,8-(7//)-dione was prepared from 3-benzyl-6-chloro-l-(3-chloropropyl)-5-phenylpyrimidine-2,4-(17/,3//)-dione and NaSH hydrate in DMF in 27% yield <1995W035296>. 

Dimethyl-3-(2-oxo-2-phenyl-ethyl--bromid lagert sich beim Kochen mit Triethylamin in Acetonitril in 2-(2-Imino-5-phenyl-2,3-dihydro-oxazol-3-yl)-4,6-dimethyl-pyrimidin um. Aus diesem werden durch Kochen in Alkoholen mit 4-Methyl-benzolsulfonsaure als Katalysator 2-Alkoxy-l-(4,6-dimethyl-2-pyrimidyl)-4-phenyl-imidazole oder durch Erhitzen mit primaren oder sekundaren Aminen ebenfalls in Gegenwart von 4-Methyl-benzolsulfonsaure 2-Alkylamino-l-(4,6-dimcthyl-2-pyrimidyl)-4-phe-nyl-imidazole erhalten374 ... 

Treatment of dimethyl l-phenyl-2-oxo-l,llb-dihydro-2//-pyrimido[2,l-a]-isoquinoline-3,4-dicarboxylate (64) with 20% hydrochloric acid, with sodium methylate in methanol, or with aniline yielded ring-opened products (Scheme 3) (67CB1094). 

Oxidation of dimethyl l-phenyl-2-oxo-l,2-dihydro-llb//-pyrimido[2,l-a]-isoquinoline-3,4-dicarboxylate (64) by potassium permanganate either in acetone or in aqueous potassium hydroxide, followed by treatment with ethereal diazomethane, gave isocarbostyril and methyl oxanilate, respectively (67CB1094). Oxidation of 4-phenyl-2//-pyrimido[2,l-a]isoquinolin-2-one with potassium permanganate in a 1 5 mixture of pyridine and 2 N potassium hydroxide yielded 2-(2-carboxyphenyl)-6-phenylpyrimidin-4(3//)-one (72CB108). 2-Methyl-4//-pyrimido[2,l-a]isoquinolin-4-one and 3,4-dihydro-2//-pyrimido[2,l-a]isoquinoline-2,4-dione with potassium permanganate afforded phthalimide in low yield. 

Catalytic hydrogenation of 2-benzyl-4-phenyl-l-oxo-l//-pyrimido[l,2-a]-quinolin-4-ium-3-olate over 5% Pd/C catalyst in acetic acid under 3.5 atm hydrogen at 50°C yielded a 5,6-dihydro derivative (83M227). 

The amino groups of isomeric 5-aminomethyl-8-chloro-6-phenyl-3-methyl-l-oxo-1/7- and -l-methyl-3-oxo-3//-pyrimido[l,2-a]quinolines were acylated with acetic anhydride at room temperature for 1 h (79CPB2927). 5,8,9-Trihydroxy-2,3-dihydro-l//-pyrimido[l,2-a]quinoline-l-carboxylic acid was acylated with acetic anhydride in pyridine at room temperature for 24 h (87T2261). 

The amino group of 3,4-dihydro-27/-pyrimido[2,l-u]isoquinoline 421 (R = H) was acylated with different isocyanates and phenyl isothiocyanate (98JMC1050). 

Hydrogenation of ethyl A -[2-(2-pyridyl)ethyl]carbamate in ethanol over Raney Ni at 130°C and 120 atm gave perhydropyrido[l,2-c]pyrimidin-1-one (67YZ663). Cyclization of ethyl Y-[2-(l,2,3,4-tetrahydro-2-quinolyl)ethyl]carbamate at 190-200°C afforded 2,3,4,4a,5,6-hexahydro-l//-pyrimido[l,6-a]quinolin-l-one (60YZ1414), whereas that of l-(2-benzamidoethyl)-6,7-dimethoxy-3,4-dihydroisoquinoline in boiling toluene with phosphoryl chloride led to 4-phenyl-9,10-dimethoxy-6,7-dihydro-2//-pyrimido[6,l-fl]isoquinoline (63YZ1043). 

Hydrogenation of l-acylamidinomethylene-l,2,3,4-tetrahydroisoquino-line (48, R = Me, R = Ph) over Pd/C gave 2-amino-4-phenyl-9,10-dimethoxy-6,7-dihydro-4H-pyrimido[6,l-a]isoquinoline via 49 (R = Me, R = Ph) (90CB493). When an ethanolic solution of l-[(benzoylamidino) methylenejtetrahydroisoquinoline (48, R = Me, R = Ph) was evaporated... 

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