Synthèse de C-nucléosides dérivés de l'hydroxy-8 (1,2,4)triazolo[1,5-c] et [4,3-c]pyrimidines

Ether and ester derivatives corresponding to the novel C-nucleosides 2-β-D-ribofuranosyl-8-hydroxy[1,2,4]triazolo[1,5-c]pyrimidine and 2-(2-hydroxyethoxymethyl)-8-hydroxy[1,2,4]TRIAZOLO[1,5-C]Pyrimidine were obtained by condensation of 5-benzyloxy-4-hydrazinopyrimidine respectively with thiobenzy1-2-(2-benzoyloxyethoxy)acetimidate hydrochloride. Cleavage of the easter group by ammonia in methanol followed by hydrogenolysis of the benzylic ether afforded the above C-nucleosides derived from heterocyclic phenols. Unambiguous structural assignment were made by UV AND ¹H and ¹³C nmr studies.     

Dérivés de l'hydroxyméthyl-5 furfural. I. Synthése de dérivés du di- et terfuranne

Addition of α, β-unsaturated sulfones or ketones to 5-hydroxmethyl-furaldehyde or related furanaldehydes in the presence of a thiazolium salt gives di or tetraketonic furan compounds. Dehydrative cyclizationled to di- and terfuryl derivatives.     

Synthèse de L'hydroxy-9 pyrimido[1,6-a]pyrimidine one-4 et dérivés

Condensation of 5-alkoxy-4-aminopyrimidines with diethyl ethoxy-methylenemalonate and with isopropylidene methoxymethylenemalon-ate, followed by thermal cyclization of the resulting enaminoesters intermediates yielded 9-alkoxypyrimido[l,6-a]pyrimidin-4-ones which were substituted in the 3 position by an ethoxycarbonyl group in the first case. Subsequent hydrogenolysis of the corresponding benzylic ethers afforded new heterocyclic phenols 9-hydroxypyrimido[l,2-a]pyrimidin-4-one and its 3-ethoxycarbonyl derivative.     

Synthèse de l'oxo-7 7H cyclohepta[b] pyridine et de quelques dérivés

This communication describes the synthesis of 7-one (7H) cyclohepta[b]pyridine and some derivatives (6,8-dimethyl; 8-methyl; 8-ethyl….). These compounds have been obtained by condensation of ketones with 2,3-diformylpyridine.     

Synthèse de dérivés de la benzo[c] quinolizine

The introduction of polar groups in planar polycyclic systems, for the purpose of studying their intercalating action, has been realized in the benzo[c]quinolizinium series. A functionalizing synthesis has been developed from 2-picolyl-and quinaldyllithium. Intermediate ketones or imines were cyclized by a quaternization reaction involving a concerted process. Structure and physico-chemical features of the compounds prepared were studied.     

Dérivés C-glycosyliques. VII. Synthèse et réactions de nitrones dérivées de sucres. Communication préliminaire

The syntheses of three types of sugar nitrones (aldonitrone, ketonitrone and α-β unsaturated aldonitrone) are described. On 1,3-dipolar cycloaddition with phenylacetylene, the aldonitrone gave two Δ₄-isoxazolines epimeric at the new asymetric carbon, while the same reaction on the ketonitrone led to a spiro-Δ₄-isoxazoline. The reaction of these nitrones with carbon nucleophiles like phenylethynylmagnesium bromide constitutes a novel chain-extension reaction in carbohydrate chemistry.     

Synthèse de nouvelles amidines bicycliques . Dérivés de la pyrimidine,de la quinazoline et de la diazépine-1,3

The synthesis of pyrrolo[1,2-α] pyrimidines is described. Several homologous compounds contain pyridine or azepine instead of pyrrole ring. They are obtained by cyclization of iminolactams with β-ketoesters, αβ-unsaturated esters, aldehydes or ketones, or diketene. The possibility of obtaining isomers is discussed.     

Recherches en série azabenzodiazépine VII. Synthése de pyrazolo[3,4-b]diazépines-1,4

Condensation of ethyl acetoacetate or acetylacetone with 4,5-diaminopyrazoles are reported and discussed. They gave new pyrazolo[3,4-b]-1,4-diazepines or intermediates which can be cyclised.     

Synthèses de 1,2,4-triazolo[4,3-d][1,4]diazépines et de 1,2,4-oxadiazolo[4,5-d][1,4]diazépines par cycloaddition dipolaire-1,3

We report here a one-step synthesis of the 4,5,6,7-tetrahydro-1H- 1,2,4,-triazolo[4,3-d][1,4]diazepine, 4-6, and 1,2,4-oxadiazolo[4,5-d][1,4]-diazepine, 7-10, by 1,3-dipolar cycloaddition of nitrile imines and nitrile oxides with 2,3-dihydro-H-1,4-diazepine, 1. In all cases these cycloaddition are peri- and regioselectives (the C ? N bond is sole affected) and occures with high yields. Structure and conformations of cycloadducts have been assigned by means of nmr analysis     

Synthèse facile de dérivés du diphényl-2,4-aza-3-bicyclo[3.3.1]nonane et du diphényl-7,8-aza-8-bicyclo[4.3.1]décane

Facile synthesis of derivatives of 2,4-diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-diphenyl-8-azabicyclo[4.3.1]decane The facile synthesis of hydantoins, cyanhydrins and aminonitriles derived from 2,4-diphenyl-3-azabicyclo[3.3.1]nonanone and 7,9-diphenyl-8-azabicyclo[4.3.1]decanone is described. Configurations at C(9) or C(10) of the new compounds wth pharmaceutical and synthetical utility is deduced from their spectral properties.     

Synthèse et stéréochimie de perhydrocyclopenta[b]furannones-3-cis et perhydrocyclopenta[b]furannols-3-cis

Synthetic route to new cis-perhydrocyclopenta[b]furan-3-ones and cis-perhydrocyclopenta[b]furan-3-ols is described. Their configurations and conformations were inferred by ¹H and ¹³C nmr spectroscopy. A certain rigidity is associated with the bond common to the two fused ring. The conformation of tetrahydrofuran-3-one ring appears to be a composite of the C, and C₂ forms depending on the C-2 substitution.