Arylidène-5 méthyl-6 4H pyridazines substitutées en 3 et systèmes a noyaux condenées

Starting from previously described pyridazinones 1 , new 3-substituted-5-arylidene-6-methyl-4H-pyridazines were prepared in order to study their pharmacological effects. The intermediate chloropyridazines 3 can undergo nucleophilic substitutions, leading to aminopyridazines 4 or to hydrazinopyridazines 5 ; the latter can involve formation of pyrazole derivatives 8 and fused heterocyclic systems such as triazolopyridazines 6 or tetrazolopyridazines 7 . The structures of the products were confirmed on the basis of their elemental analysis and ¹H nmr spectral data.     

Synthèse et étude structurale de dérivés substitués en -2 du thiazolidine carboxylate d'éthyle-4 (R)

Pharmacological properties of thiazolidine derivatives are of great interest. For this purpose we prepared two series: 2-hydroxyalkyl-4-carbethoxythiazolidines and 2-carbalkoxyalkyl-4-carbethoxythiazolidines. Their syntheses involve a condensation reaction between L-carbethoxy-cystein and several α-hydroxyketones or β-ketoesters. Compounds 4 and 5 was obtained as an unequal mixture of diastereoisomers. Protons nmr spectra at 300 MHz in the presence of trifluoroacetic acid shows a modification of diastereoisomer percentages which indicate the existence of an equilibrium through an imminium ion intermediate. Therefore, the stereoselectivity observed reflects the relative stability of the different diastereoisomers.     

Sur quelques réactions par décharge électrique dans les systèmes phosphine-eau,phosphine-eau-ammoniac et phosphine-eau-ammoniac-méthane

Electric discharge reactions in the systems PH₃ + H₂O, PH₃ + H₂O + NH₃ and PH₃ + H₂O + NH₃ + CH₄ have been studied. In the system PH₃ + H₂O, they produce polyphosphines (insoluble in water) and hypophosphorous, phosphorous and orthophosphoric acids. In the system PH₃ + H₂O + NH₃, besides the above products, hypophosphate, pyrophosphate, polyphosphates and possibly polyhyphosphates are also present. In the system PH₃ + H₂O + NH₃ + CH₄, besides all the above inorganic P compounds, organic phosphorus derivatives such as aminoalkyl phosphates and aminoalkanephosphonates are also formed, as well as other non-phosphorus containing organic products (amino acids, ethanolamine, etc.). The presence of phosphine (or its transformation products), seems to promote condensation reactions in this system since the ratio of amino acids found after hydrolysis (in 6N HCl) to amino acids found before hydrolysis is greater in this system. than in the system (CH₄+ H₂O+ NH₃)iiot containing phosphine.     

Spectres ir de quelques dérivés 3-acyl de la coumarine

The IR spectra of sixty-nine coumarin-3-acyl derivatives have been recorded and analysed in the region 4000-660 cm⁻¹ and 4000-400 cm⁻¹.

Band assignments are proposed as far as possible. Some absorption bands are characteristic for the examined coumarins and can be used in recognizing and differentiating a coumarin structure in an unknown compound.     

Equilibres conformationnels de dérivés de sucres à insaturation terminale

The conformation in solution of several unsatured sugars of the general type XHC?CH—glycosyl has been studied by NMR. In the trans series, the population of the sterically permitted gauche conformer increases with the M-ability of X. In the cis series, the population of the trans conformer increases with the space requirements of X. These phenomena are discussed.     

Additions radicalaires du tétrahydrothiophène à des dérivés éthyléniques: Préparation de tétrahydrothiophènes substitués en 2

Di-t-butyl peroxide induces a free radical addition of tetrahydrothiophene to ethylenic compounds. The main products arise from an α-attack of the substrate. This reaction seems to be an interesting synthesis of these heterocycles.     

Dérivés propargyliques,XII et dérivés de la décahydroquinoléine,II Alkynyl-4, alkényl-4 et alkyl-4-décahydroquinolinols-4 N-substitués

The authors describe the synthesis of decahydro-4-quinolinones and N-substituted 4-alkynyl-, 4-allyl- and 4-alkyldecahydro-4-quinolinols and discuss the stereochemical problems of this compounds.     

Etude de la fragmentation par impact électronique en ions positifs et négatifs de dérivés nitrés de l'amino-2-benzothiazole

Study of Positive and Negative Ions Electron Impact Fragmentation of 2-Amino-benzothiazole Nitro Derivatives The positive and negative ions mass spectra of 2-amino-4,6-dinitrobenzothiazole ( 1 ), 2-amino-4-nitrobenzothiazole ( 2 ), 2-amino-6-nitrobenzothiazole ( 3 ) are reported and discussed. These compounds give an intense molecular ion and show interesting fragmentations in both positive and negative ions spectra. Specific ¹⁵N-labelling was used in order to confirm the fragmentation patterns.     

Contribution á l''étude des tris(dialcoylamino)stibines : II. Étude des réactions avec les dérivés carbonylés et les dérivés bifonctionnels

The reaction of Sb(NMe₂)₃ with aldehydes and ketones leads to enamines or diamines according to the degree of substitution of the carbonyl compound. With acids Sb(NMe₂)₃ gives amides, and with β-diketones and β-keto esters it gives enamines. With bifunctional compounds such as diols, secondary diamines or aminoalcohols, different heterocyclic compounds are formed according to the ratio of bifunctional compound to antimony.     

Résolution de spectres RPE par régression non linéaire. Application à des radicaux anions dérivés de thiazoles substitués

A non-linear regression method for the resolution of EPR spectra is described. The theoretical model is fitted with the experimental spectrum and the error on each parameter is calculated. The method is applied to the radical anions of 2-nitro-4-methyl thiazole, 4-p-nitro-phenyl-thiazole and 5-p-nitro-phenyl-thiazole.     

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.     

Radicaux libres dérivés de sucres. V. Dérivés d'osamines N-hydroxylées et composés voisins Communication préliminaire

Free sugar radicals. V. Deoxyhydroxylaminosugar derivatives and related compounds We describe several synthetic routes to deoxyhydroxylaminosugar derivatives of the type Glyc-N(OH)-R where Glyc stands for a sugar moiety linked by any of its C-atoms except the anomeric one and R for one of the following substituants: H-atom, acyl, phosphoryl groups, aminoacid or sugar residues. Compounds of the above structure are potentially close analogs, homoisosteres, ? NOH? replacing ? O? , of biochemically important molecules. Under aerobic conditions, solutions of these derivatives contain minute concentrations of the corresponding nitroxide radicals which do not decrease significantly the resolution of the NMR. spectra but render these compounds usable as a new kind of spin labels. Spectroscopic properties (¹H-NMR., ¹³C-NMR., ESR.) of some of these compounds are reported.     

Le mécanisme de la réduction polarographique des dérivés ditosyloxylés et son implication en électrochimie préparative

The cleavage of a single SO₂? O bond occurs during the polarographic reduction of a tosyloxy group (p? CH₃C₆H₄SO₂O = TsO) in aprotic medium and intramolecular cyclisation may ensue when a second TsO group is present on the same molecule. The polarographic behaviour of aliphatic ditosyloxy derivatives is discussed on the assumption that oriented vicinal derivatives at the interface assume a conformation which resembles the geometry of the transition state for an intramolecular elimination with anchimeric assistance of one of the tosyloxy groups. This situation favours the electron transfer, whereas the same geometric requirements hinder the intramolecular interaction of the TsO groups of the oriented non-vicinal derivatives. This interpretation agrees well with the fact that the large scale electrolysis of vicinal ditosyloxy derivatives give much higher yield of cyclic ethers than the higher homologues. It is also shown that intramolecular interaction between TsO groups can occur through an intervening double bond in a non-vicinal derivative.     

Equation de Karplus appliquée à des systèmes sp2–sp3

A method of best fitting for the calculation of vicinal coupling constants is presented for sp²-sp³ systems. Results for 68 vicinal coupling constants from 32 different products are presented. We obtain the best Karplus-type equation to date with a dispersion factor of 31,01%.     

Structure cristalline et moléculaire d'un dérivé méthyl-hexopyranoside à C(4) hybridé sp2

The derivative C₁₃H₁₉NO₅ crystallizes in space group P2₁2₁2₁ with a = 9.371, b = 11.815, c = 13.207 Å and Z = 4. The structure was solved by direct methods and refined by full-matrix least-squares to R = 0.058. The pyranose ring exists in the ³S₁ conformation (or in the equivalent, but here structurally less consistent, ⁰S₄ conformation). The dioxolane ring has an envelope conformation. Strong intramolecular interactions between the bulky substituents suggest that the ensuing strain energy is assumed, for a significant part, by the twisted-boat conformation of the pyranose ring.     

Systèmes Aromatiques à 10 Électrons π Dérivés de l'Aza-3a-pentalène: XXVI—Etude de quelques Dérivés Polyazapentaléniques en Résonance du Carbone-13

The ¹³C n.m.r. study of nine azapentalenes was carried out and all the signals were assigned. In one case, very unusual couplings between the carbon atoms and the proton bonded to the pyrrole nitrogen atom were observed. The usefulness of ¹³C n.m.r. spectroscopy for the study of annular tautomerism is demonstrated.