Sur la synthèse de quelques furochromènes,analogues pharmacochimiques de la xanthylétine et de la séseline

Some furochromenes substituted at the 2-position by an electron-attracting group were obtained starting from ortho-hydroxyformyl derivatives of 2,2-dimethyl-2H-chromene following various processes which are indicated. These new furochromenes are pharmacochemical analogues of some natural pyranocoumarins, and as such they are potential photosensitizers.     

Diastéréotopies dans la série du benchrotrène

¹H and ¹³C spectra of mono-and disubstituted (benzene)-tricarbonylchromium complexes have been analysed. The influence of the substituents is discussed and special attention is paid to the diastereotopy resulting from different types of chirality. The racemic pseudosymmetric isomer and the two meso pseudoasymmetric isomers of the glycols (OC)₃CrC₆H₄(CHOHCH₃)₂ are compared. The stereochemical requirements are also examined.     

Résonance Magnétique Nucléaire en phase nématique. Exploration de la barrière d'empêchement à la libre rotation de la monofluoroacétone

The NMR spectra of monochloro-, monobromo- and monofluoroacetone (CH₃? CO? CH₂X with X = Cl, Br, F) oriented in a nematic phase have been measured and the direct dipolar coupling constants determined. The barrier to internal rotation for the CH₂F group has been studied for fluorine compound using various hypotheses. The best agreement with IR data has been obtained using the potential equation V(θ) = Σ_n V_n × (1 – cos nθ)/2 and a Boltzmann distribution of the CH₂F group (V₁ = 250 ± 50 cal.mol^?1, V₂ = 1650 ± 100 cal.mol^?1, V₃ = ?1000 ± 100 cal.mol^?1).     

Fluorénacènes et fluorénaphènes Synthèses dans la série des indéno-fluorènes,XIX Dérivés tétraméthylés du trans-fluorénaphène et du trans-fluorénacène

By condensation of isophthaloyldichloride resp. of terephthaloyldichloride with 4-bromo-1,2-xylene according Friedel-Crafts, followed in each case by a double cyclisation and a final reduction, the 2,3,9,10-tetramethyl-7,12-dihydro-indeno[1,2-a]fluorene resp. the 2,3,8,9-tetramethyl-6, 12-dihydro-indeno[1,2-b]fluorene are synthesized.     

Diénamines hétérocycliques. III. Réexamen de la réaction de la base de Fischer avec le tétracyanoéthylène

Heterocyclic dienamines III. A re-examination of the reaction of Fischer's base on tetracyanoethylene Depending on the order of addition, Fischer's base 5 (1,3,3-trimethyl-2-methylidene-indoline) reacts 1:1 with tetracyanoethylene to give either the tricyanovinylation product 6 or the spiro compound 7 . A skeletal rearrangement of a zwitterionic intermediate can explain the formation of the spiro compound. The latter undergoes a thermal isomerization yielding by ring expansion the tetrahydroquinoléine 8 . On reaction with LiAlH₄ or CH₃ONa 7 and 8 lead both to triazatetracycles. All structures are assigned on the basis of spectral data.     

Synthèse et réactivité des bromhydrines dérivées de la chromone

Bromohydroxylated derivatives of chromone are obtained by addition of N-bromosuccinimide in dimethylsulfoxide. The configuration and conformation of these compounds are confirmed by NMR spectroscopy. Alkaline alcoholates react with these bromohydrins to give a ring contraction into 2-formyl-3-benzofuranone.     

Extension de la méthode du «logarithme limite» [1] pour la détermination de la composition et de la constante de stabilité des complexes

A study of the conditions of applicability to weak complexes of the relation log x = v log V + log (β_v,cC^c) = f(logV), where V and C are variable and constant total concentrations of the constituants of the complexe, shows that for conditions other than C ? V, another function φ(log V) accounts better for the formation equilibrium of the complexe. From f(log V) and φ (log V) a relation t(log V) is derived whose simple analysis permits the determination of the composition and the stability constant of weak complexes. Applications are given to 1:1, 1:2, 2:2 composition.     

Etudes sur les matières végétales volatiles. CIC. Sur la structure du «diépoxyde d'allo-ocimène»

The allo-ocimene diepoxides described in our recent communication are trans (? CH?CH? ) as announced, and not cis/trans stereoisomers.     

Etude de la décomposition thermique d'azido dithiényl-1,2 éthènes et éthanes

Thermal decomposition of azido-1,2-dithienylethenes 1 gave thienyl 4H-thieno[3,2-b]pyrroles 3 . For the 3,4-disubstituted thiophene derivatives 2 , the same reaction led to the amino-1,2-dithienylethenes 4 . In contrast, only azido-1,2-dithienylethanes 7 led to thienyl-5,6-dihydro-4H-thieno[3,4-b]pyrroles 8 . The structure of the obtained derivatives was established on the basis of ¹H nmr, ir, and mass spectral data.     

Recherches sur la stéréochimie des diènes fonctionnels—X: Etude par Résonance Magnétique Nucléaire d'alcoxybutadiènes 1,3

The nuclear magnetic resonance parameters of 1,3 alkoxy-butadienes are strongly dependent on the cis or trans configuration of the ethylenic systems. A discussion of the different types of coupling constants and of the additivity of substituent effects on the chemical shift is proposed. The results are applied to the identification of isomers and to the study of the electronic and stereochemical structure of each configuration. The conformational equilibrium about the C? C and C? O bonds is discussed with special reference to the aromatic solvent and temperature effects.     

La configuration du «carquéjol» (Isopropényl-2-méthylène-3-cyclohexène-4-ol) et la conformation privilégiée de l' ortho-néo-isomenthol

The complete stereochemistry of carquejol (= cis-(2S)-isopropenyl-3-methylene-cyclohex-4-en-1-ol) is described. The absolute configuration was obtained from the circular dichroism of the corresponding 0-menthones. Carquejol and its reduction products, having the all-cis configuration, appear from NMR. measurements to prefer a conformation having the hydroxyl (or acetoxyl) group axial and the isopropenyl (or isopropyl) group equatorial, even when the exo-methylene group is reduced to methyl. The mass spectra of the compounds are briefly described.     

Fluorénacènes et fluorénaphènes Synthèses dans la série des indéno-fluorènes XIV [1] Nouvelle synthèse du trans-fluorénacène

A new synthesis of 6, 12-dihydro-indeno [1,2-b] fluorene (trans-fluorenacene) in 9 steps starting from fluorene (overall yield 24,5%) is recorded. By partial oxidation of the hydrocarbon its 6-oxo derivative is also obtained.     

Résonance Magnétique Nucléaire en phase nématique. Exploration de la barrière d'empêchement à la libre rotation pour le fluorure d'acroyle et l'acroléine

The NMR spectrum of acrolein and acroyl fluoride (CH₂?CH? COX with X?H and F) oriented in a nematic phase has been measured and information about conformational equilibrium s-cis ? s-trans has been obtained. The barrier to internal rotation of the COX group has been studied with various hypotheses. Good agreement between experimental and calculated spectra has been obtained using the potential equation V(?) = Σ_nV_n(1 – cos n?)/2, with V₁ = ?200 cal mol^?1, V₂ = 1500 cal mol^?1 and V₃ = 400 cal mol^?1 for the fluorine compound, and V₁ = 1200 cal mol^?1, V₂ = 3000 cal mol^?1 and V₃ = 2000 cal mol^?1 for acrolein; this last compound is found to be mostly in the s-trans conformation.     

Synthèse des (R)- et (S)-O-isopropylidène-1,2-glycérols. Détermination de la pureté optique

Synthesis of the (R)- and (S)-Glycerol Acetonides. Determination of the Optical Purity The optical purity of (R)-glycerol acetonide ( 1 ) and (S)-glycerol acetonide ( 1 ′) has been determined with great accuracy by gas chromatography after derivatization. The optical purity of (S)-glycerol actonide prepared from D -mannitol was > 99.4% while for (R)-glycerol acetonide obtained from L -serine it was 95%.     

Application de la réaction de Wittig à la synthèse de dérivés de bromoénosuloses et d'esters bromoénuroniques. Note de laboratoire

Use of the Wittig reaction for the synthesis of derivatives of bromoenosuloses and bromoenuronic esters Treatment of 3-O-benzyl (or 3-O-methyl)-1, 2-O-isopropylidene-α-D -xylo-pentodialdo-1, 4-furanoses ( 2 or 1 ) with acetylbromomethylidenetriphenylphosphorane ( 3 ), benzoylbromomethylidenetriphenylphosphorane ( 4 ) or bromoethoxycarbonylmethylidenetriphenylphosphorane ( 5 ) gave in good to excellent yields the expected enose ( 6--11 ). In all cases but one ( 8 where some 10% of the E-isomer was formed) the reaction led to the exclusive formation of the Z-isomer whose configuration was established by NMR.     

Synthèse partielle et propriétés oncostatiques des pseudo-tubulosines,analogues de l'émétine et de la tubulosine

Partial Synthesis and Oncostatic Properties of Pseudotubulosines, Analogues of Emetine and Tubulosine Pseudotubulosines, structural analogues of emetine and tubulosine, have been synthesized by either Pictet-Spengler or Bischler-Napieralski condensation from dihydrocorynantheal or corynantheidal. Spectral data, cytotoxic and oncostatic properties of these new alkaloids are described.     

Sur la synthèse d'acides thiazolotriazolylacétiques

During the synthesis of thiazolotriazolylacetic acids, the condensation of ethyl 4-chloro-3-oxobutyrate with triazolinethiones was studied. The use of an alkaline reagent (triethylamine) leads only to S-alkylation and not to the expected cyclized product. The cyclization of the intermediate β-ketoester is observed only by use of acidic reagents (phosphorous oxychloride, hydrogen chloride).     

Synthèse énantiospécifique de la (+)-(R)-éthyl-6-dihydro-2,3-méthyl-2-4H-pyranone-4, phéromone de la mite Hepialus hecta L

Enantiospecific Synthesis of (+)-(R)-6-Ethyl-2,3-dihydro-2-methyl-4H-pyran-4-one, Sex-pheromonal Component of the Male Swift Moth Hepialus hecta L . A new synthesis of (+)?(R)-6-ethyl-2,3-dihydro-2-methyl-4H-pyran-4-one ((R)- 8 ), sex-pheromonal component of the male swift moth Hepialus hecta L., has been performed from (?)-(R)-1-(1,3-dithian-2-yl)propan-2-ol with an enantiomeric excess of ? 97%.     

Synthèse de spirohydantoines dérivées du diphényl-2,4-aza-3-bicyclo-[3.3.1]nonane et du diphényl-7,9-aza-8-bicyclo[4.3.1]decane par réaction de Bucherer dans la N,N-diméthylformamide: Influence de la température et cours stéréochimique. Communication préliminaire

Synthesis of Spyrohydantoines Derivatives of 2,4-Diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-Diphenyl-8-azabicyclo[4.3.1]decane via Bucherer Reaction in N,N-Dimethylformamide: Influence of the Temperature and Stereochemical Path The unreactives ketones related to 2,4-diphenyl-3-azabicyclo [3.3.1]nonan-9-one to the Bucherer reaction in usuals conditions show excellent reactivity in DMF. as unique solvant. The stereochemical paths of these reactions and the synthetic utility of the temperature modification are described.     

Fluorénacènes et fluorénaphènes synthèses dans la série des indéno-fluorènes,XVII. Dérivés méthylés du cis-fluorénacène,du trans-fluorénacène et du trans-fluorénaphène

By condensation of the chlorides of the three 9-oxo-fluorene-2-, -3-, and -4-carboxylic acids with 4-bromo-1,2-xylene on one side, and of the chlorides of o-bromobenzoic acid, 2-bromo-4-methyl-benzoic acid and 2-bromo-4,5-dimethyl-benzoic acid with fluorene, 2-methylfluorene and 3-methylfluorene on the other side, followed by direct or indirect cyclisation and by final reduction, several new methyl derivatives of the indenofluorenes I, II and IV are synthesized.