Etude des conditions d'accés aux 6H-, 7H- et 11H-pyrimidino-[4,5-a], [4,5-b], [5,4-a] [5,4-b] et [5,4-c]carbazoles. 1

The synthesis of dihydropyrimidinocarbazoles 12,15 and 18 was achieved by cyclization of tetrahydrocarbazolones with triformamidomethane. The oxidation with potassium permanaganate of dihydropyrimidinocarbazoles gave the pyrimidinocarbazoles 13,16 and 19. The application of the Sandemeyer reaction to amiononitrocarbazoles gave cyanonitrocarbazoles which could be reduced to aminocyanocarbazoles 1 and 7. Intramolecular cyclization of the carbazoles 1 and 7 afforded 3,4-dilhydro-4-oxo-6H-pyrimidino[5,4-b]carbazole 2 and 1,2-dighydro-1-oxo-6H-pyrimidino[5,4-b]carbazole 10 was obtained by cyclization of quinazolinyl hydrazone 9 with hydrochloric acid and acetic acid. The structure of the derivatives was determined by ¹H-nmr and the Overhauser effect.     

Synthèse et étude physicochimique des 1,2,4-triazolo[4,3-a]-pyridines et des 1,2,4-triazolo[2,3-a]pyridines

The synthesis of 1,2,4-triazolo[4,3-a] and [2,3-a]pyridines 7, 8 was achieved by cyclization of 2-hydrazino-8-nitropyridine 3a with formic acid. The 4,5,6,7-tetrahydro-1,2,4-triazolo[2,3-a]pyridine 13 and 8-amino-1,2,4-triazolo[2,3-a]pyridine 9 were obtained by catalytic hydrogenation. The reduction of triazolo pyridine 8 using stannous chloride led to the intermediate compound 10 which with acetic anhydride afforded 8-acetylamino-5-chloro-1,2,4-triazolo[2,3-a]pyridine 10a . The structure of the derivatives was determined by ¹H-nmr (DMSO-d₆).     

Pyrrolo[1,2-d]triazines-1,2,4 III. Etude de la dioxo-1,4 tetrahydro-1,2,3,4 pyrrolo[1,2-d]triazine-1,2,4

1,4-Dioxo-1,2,3,4-tetrahydro-l,2,4-pyrrolo[l,2-～-1,2,4-triazine (1) was synthesized either by cyclising the N-carbethoxyhydrazide of pyrrole-2-carboxylic acid (2) or by alkaline rearrangement of 2-(2-pyrrolyl>5-oxadi- azolone (3). The methylation reactions of the dilactam 1 were achieved with dimethyl sulfate or diazomethane and afforded mixtures of U-methylated and N-methylated derivatives which were isolated by gas chromatography and the structures of which were assigned using ir and ¹H nmr spectra.     

as-Triazino[4,5-a]indoles. II. Etude des as-triazinoindolones

The synthesis of 1,2-dihydro-1-oxo-as-triazino[4,5-a]indoles was achieved by rearrangement of 2-oxadiazolyl-indoles under alkaline conditions or by cyclisation of indole-N-ethoxymethylid-ene hydrazides. The cyclisation of the N-carbethoxyhydrazone of the indole-2-carboxaldehyde gave the 1,2-dihydro-1-oxo-as-triazino[4,5-a]indole. The study of the lactim-lactam tautomerism was accomplished using the ir and nmr spectra.     

Pyrrolo[1,2-d]triazines-1,2,4. I. Dérivés pyrroliques

Pyrrole hydrazides and hydrazones were synthesized from pyrrole-2-carboxylic acid and pyrrole-2-carboxaldehyde, The 2-pyrrolyloxadiazoles and thiadiazoles were obtained by cyclising the pyrrole hydrazides with phosphorus oxychloride and tetraphosphorus decasulphide. These derivatives have been used for the synthesis of pyrrolo[1,2-d]-1,2,4-triazines by cyclisation or rearrangement.     

Pyrrolo[1,2-d]triazines-1,2,4. II. Etude des pyrrolo[1,2-d]triazinones-1 et -4

The synthesis of 1,2-dihydro-1-oxopyrrolo[1,2-d]-1,2,4-triazines was achieved by rearrangement of 2-pyrrolyloxadiazoles under alkaline conditions or by cyclisation of pyrrole N-ethoxymethylidene hydrazides. The cyclisation of the N-carbethoxy hydrazone of the pyrrole-2-carboxaldehyde gave the 3,4-dihydro-4-oxopyrrolo[1,2-d]-1,2,4-triazine. Electrophilic substitution reactions of the 1- and 4-pyrrolotriazinones were made either on the lactam nitrogen with methyl sulphate, benzyl chloride and monochloroacetic acid or on the pyrrole ring with bromine and nitric acid. The structure of the derivatives was determined by ¹H nmr.