1.7- Dimethyl-2-nitro-4,5,9,10-tetrahydro

Cyclocondensation of 2-(nitromethylene)perhydropyrimidine (379) and dimethyl acetylenedicarboxylate yielded a mixture of 9-nitro-l,2,3,4-tetrahydro-6-oxo-6//-pyrido[l,2-n]pyrimidin-8-carboxylate 380 and a pyr-rolo[l,2-n]pyrimidine-7-ylideneacetate 381 (93BCJ2118). Their ratio... 

Vielsmeier-Haack formylation of 2-nitro-6,7,8,9-tetrahydro-l 1 //-pyrido-[2,l-b]quinazolin-l 1-one (120, R = 2-N02) (84JHC219) and 1,2,3,4,6,7,8,9-octahydro-ll//-pyrido[2,l-6]quinazolin-l 1-one and its 8- and 9-methyl derivatives (87JHC1045) with a mixture of phosphoryl chloride and dimethyl-formamide at 15-20°C gave 6-formyl-2-nitro-5,7,8,9-tetrahydro- (122) and 6-formyl-l,2,3,4,5,7,8,9-octahydro-ll//-pyrido[2,l-b]quinazolin-ll-ones. 

The amino moiety of the 3-carbohydrazide group of unsaturated and 6,7,8,9-tetrahydro-4-oxo-47/-pyrido[l,2-n]pyrimidine-3-carbohydrazides was condensed with acetone and 5-nitro-2-furoaldehyde (830MR687 88EUP252809). The reaction of 6-methyl-6,7,8,9-tetrahydro-4-oxo-4//-pyrido[l,2-a]pyrimidine-3-carbohydrazide with diethyl 2-[2-dimethyl-amino)vinyl]-6-methylpyridine-3,5-dicarboxylate in boiling ethanol for 4 hours afforded N-( 1,6-naphthyridin-6-yl)-4-oxo-4//-pyrido[ 1,2-a]pyrimi-dine-3-carboxamide 426 (85MIP1). 

In contrast, dipolar aprotic solvents possess large relative permittivities (sr > 15), sizeable dipole moments p > 8.3 10 ° Cm = 2.5 D), and average C.f values of 0.3 to 0.5. These solvents do not act as hydrogen-bond donors since their C—H bonds are not sufficiently polarized. However, they are usually good EPD solvents and hence cation sol-vators due to the presence of lone electron pairs. Among the most important dipolar aprotic solvents are acetone, acetonitrile [75], benzonitrile, A,A-dimethylacetamide [76, 77], A,A-dimethylformamide [76-78], dimethylsulfone [79], dimethyl sulfoxide [80-84], hex-amethylphosphoric triamide [85], 1-methylpyrrolidin-2-one [86], nitrobenzene, nitro-methane [87], cyclic carbonates such as propylene carbonate (4-methyl-l,3-dioxol-2-one) [88], sulfolane (tetrahydrothiophene-1,1-dioxide) [89, 90, 90a], 1,1,3,3-tetramethylurea [91, 91a] and tetrasubstituted cyclic ureas such as 3,4,5,6-tetrahydro-l,3-dimethyl-pyr-imidin-2-(l//)-one (dimethyl propylene urea, DMPU) [133]. The latter is a suitable substitute for the carcinogenic hexamethylphosphoric triamide cf. Table A-14) [134]. 

Recent work on the thermal indolization of arylhydrazones has introduced new synthetic possibilities for azaindoles. Kelly et al. refluxed cyclohexanone and deoxybenzoin 2-pyridylhydrazones in diethylene glycol to give 5,6,7,8-tetrahydro-a-carboline (42, R = H) and 2,3-diphenyl-7-azaindole in 70 and 56% yields, respectively, compared with 53 and 12% reported earlier. Similarly, y-carboline 29 was obtained in 95 % yield from cyclohexanone 4-pyTidylhydrazone (lit. 48% ). Several 7-azaindole derivatives were prepared in the same manner. The yields ranged from 5 % for azaindolenine (31) to 88% for 3-phenyl-7-azaindole. 3,3-Dimethyl-7-azaindolenine was obtained in 47 % yield from the isobutyralaldehyde hydrazone. The novel cyclic compounds 40 and 41 were obtained from the 2-pyridylhydrazones of cyclopentanone, a-indanone, and a-tetralone in 67, 95, and 77% yields, respectively. Unfortunately, all attempts to cyclize the acetone, pyruvic acid, and ethyl pyruvate hydrazones were unsuccessful. Also, cyclohexanone and methyl ethyl ketone 5-nitro-2-... 

Furan 2-Aminomethyl-5-(2,4-dioxo-1,2,3,4-tetrahydro-pyrimidino)-2,5-dihydro- IV/lc, 578 Imidazo(l,2-a]pyridin 1,5-Dimethyl-8-nitro-7-oxo-l,2,3,7-tetrahydro-E15/3, 2790 [cycl. (R2N)2C = CH-N02 4- Diketen] 1,3-Oxazol 4-Cyan-5-(diethoxy-methylen-amino)- E4, 565 (Het — NH2 + Orthoester) Pyrazin 3-Amino-2-methoxycarbo-nyl-5-propanoyl- E9b/2, 324 (H - CO-R)... 

Oxazin 5.5-Dimethyl-2-(5-nitro-2-furyl)-3-nitroso-tetrahydro-EI4a/2, 718 (HO — C — C —C— NH2/R — CHO/HN02)... 

Dioxo-3-ethyl-l, 5,6,7-tetrahydro- 677 Pyrazolo[3,4-d]-l, 3-oxazin l,3-Dimethyl-4-oxo-6-(2-oxo-propyl)-dihydro- 557 1- Acyl-3-methylthio-6-oxo-l,6-dihydro- 676 2- Benzyl-6-(4-nitro-phenyl)-4-oxo-2,4-dihydro-676 4-Amino-7-chlor-phenyl- 976 2-(4-Aminosulfonyl-phenyl)-4,7-dichIor- 977 2-(4-Aminosulfonyl-phcnyl)-4,7-dihydroxy- 922 4-Anilino-7-chlor-2-(3-thienyl)- aus 4,7-DichIor-2-(3-thicnyI)- pyriclazino-[4,5-d]-l,3-thia7.ol)/Ethanol 976 7-Chlor-4-ethoxy-2-methyl- 972 7-Chlor-4-methoxy-2-phenyl- 972 7-ChIor-4-(3-pyrroIidino-propyloxy)-2-(2-thienyI)- 972... 

A three-component condensation of 3-amino-l, 2,4-triazole (or its 5-Me and 5-methylthio derivatives), 1 and DMF-dimethylacetal afforded 8,9-dihydro[l,2,4]triazolo[l,5-fl]quinazolin-6(7H)-ones (06RCB1224). Condensation of 3,4,5-triamino-l,2,4-triazole with aromatic aldehydes and dimedone afforded partially hydrogenated 9-aryl-[l,2,4]triazolo[5,l-frJquinazolin-8-ones. The structure of 2-amino-6,6-dimethyl-3-(4-nitro-benzylidene)amino-9-(4-nitrophenyl)-5,6,7,9-tetrahydro[l,2,4]triazolo[5,l-fr]-quinazolin-8-one was confirmed by X-ray analysis (05RCB2903). 

Nitro-2,6-dioxo-1,3-dimethyl-4-[2-( 4-dimethyl-amino-ph enyl) - vinyl]- h ex ahydro- 609 5-Nitro- 2,6-dioxo-1,3-dimethyl-4-[ 2-( 4-methoxy--phenyl)-vinyl]-hexahydro- 609 5-Nitro-2,4-dioxo-6-methyl- 1,3-diathyl-1,2.3,4-tetrahydro- 500... 

Nitro-6-hydrazino-4-hydroxy- 532 5-Nitro-5-methyl-1,3-dibenzyl-hexahydro- 504 2-Oxo-hexahydro- 315, 318 2-Oxo-4-mercapto- 1-methyl-1,2-dihydro- 318 2-Oxo-1-methyl-hexahydro- 318 5-Oxo-1,4,5.6-tetrahydro- 315, 317 5-Phenylazo-6-hydroxy-2,4-dimethyl- 553 1 - (5-O- Phospho-/ - d-ribosyl)- 4-hydroxy- 2-oxo-... 

Alkyl-l-(3,4-dimethoxy-phenyl)- -jodid 5-Brom-8-nitro 2-alkyl- 276 7-ChIor-4-hydroxy-2-benzyl- -chlorid 276f. 2,2-Dimethyl-1,2,3,4-tetrahydro- -jodid 675 5-Hydroxy- 2-athyl- -bromid 275 f. 2-[2-lndolyl-(3)-athyl]-4,5-dimethoxycarbonyl--bromid 280 5-Nitro-2-alkyl- 276... 

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