Structure et synthèses nouvelles dans la série des amino-4 dihydro-5,6 méthyl-6 pyrones-2

Primary and secondary amines react with 4-hydroxy-5,6-dihydro-Z-pyrones at position 4, and not at position 2 as previously indicated. However, a new series of compounds is obtained by this reaction, some of them exhibiting therapeutic properties. Reactivities of dihydropyrones and pyrones are compared.     

Thio-I ehromannones 5,8-disubstituées et synthèses dans la série du thiéno[4,3,2-de] thiochromanne

With the aim of obtaining the thieno[4,3,2-de] thiochromane structure, various 5,8-disubstituted derivatives of [1]thiochromanone have been synthesized. The structures of the compounds thus obtained and of the intermediates used in their syntheses were confirmed by nmr spectroscopy or by chemical procedures.     

Recherches dans la série des cyclitols,XLI. Synthèses de deux cyclopentane-pentols

Two new cyclopentane-pentols, namely the 1, 2, 3, 4/5- and 1, 2, 3/4, 5-isomers have been prepared by hydroxylation of the three 3, 4, 5-trihydroxy-1-cyclopentenes. The stereoselectivity of some hydroxylating agents is discussed.     

Recherches dans la série des cyclitols XLIV. Synthèses de cycloses dérivés du cyclopentane

The conversion to free ketoses by transketalisation of ethylene-ketal and/or isopropylidene derivatives of polyhydroxy-cyclopentanones has been investigated. The preparation of 2, 3-dihydroxy-cyclopentanone and of 2, 3-dihydroxy-cyclopentenone has been 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.     

Action des composes organomagnesiens sur les pyrones-2-VII : Etude de la stabilite relative des hydroxy-6 dihydro-5,6 2h-pyrannes et des cetols tautomeres correspondants

In the reaction between organomagnesium compounds and 2-pyrones, the relative stability of the 6-hydroxy 5,6-dihydro 2H-pyrans and their tautomeric forms (ketols) has no influence on the reaction pathway. When ethylenic ketols are obtained, the corresponding tautomeric dihydropyranols are prepared in a selective way by reaction of nucleophilic reagents on the 3,6-dihydro-2-pyrones. In the other hand, the exclusive formation either of the dihydropyranols or of the unsatured ketols E, during these two reactions, shows up that here is no equilibrium between these two entities in the experimental conditions.     

Recherches dans la série des cyclitols,XL. Préparation de cyclopentane-triols et de cyclopentène-triols et -diols

Two as yet unknown cyclopentene-triols have been prepared. The replacement of the halogen of cyclopentene derivatives brominated in the allylic position has been investigated. In the presence of dimethyl sulfoxide and sodium hydrogen carbonate, the bromine of some of the above mentioned allylic derivatives or the tosyloxy group of a dibenzoyloxy-monotosyloxy-cyclopentane derivative is replaced by a hydroxyl group without formation of any keto compound. The mechanism of action of the substitution agents is discussed.     

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.     

Recherches dans la série des cyclitols XLII. Synthèses de cyclitols tout-cis dérivés du cyclopentane; préparation des cyclopentane-tétrol et - pentol tout-cis

All-cis cyclitols derived from cyclopentane have been prepared in two ways: (i) by LiAlH₄ reduction of all-cis epoxypolyos; (ii) by dimethyl sulfoxide treatment, in the presence of sodium hydrogencarbonate, of brominated derivatives containing a neighbouring benzoyloxy group; under these conditions, the halogen is replaced by a cis-oriented hydroxyl group. Thus all-cis cyclopentane-tetrol and -pentol have been prepared; their configuration has been confirmed by NMR. spectroscopy.     

Recherches dans la série des cyclitols XXXIX RMN. de protons d'hydroxyles de cyclopentane- et de cyclopentène-polyols

Several mono-, di-, and tri-hydroxy derivatives of cyclopentane and cyclopentene have been studied by NMR. spectroscopy. The chemical shifts and the coupling constants of the OH groups have been correlated with their position, with their configuration and, in some cases, with their conformation.     

Recherches dans la série des cyclitols XXXVII Etude par spectrométrie de masse

Low resolution mass spectra of cyclohexane-triols, -tetrols, -pentols and -hexols and of some of their deuterium labelled derivatives have been measured. The results indicate that for some geometrical isomers quantitative differences between ion intensities are significant, allowing to deduce the stereochemistry of the molecule from its mass spectrum. In all these compounds the electron impact induced elimination of water occurs mainly by interaction between OH groups. There is a correlation between the relative abundance of (M – H₂O)⁺ and (M ?2 H₂O)⁺ ions and the number of axial hydroxyls in the more stable conformation of the molecule. Difficulties encountered in deducing fragmentation patterns, and determination of number and position of deuterium atoms in the molecule of ms-inositol are discussed.     

Synthèses dans la série des bis-indéno-fluorènes I. Le dihydro-13, 15-5H-bis-indéno[1, 2-a;1′, 2′-h]fluorène

The synthesis of 13,15-dihydro-5H-diindeno[1,2-a;1′,2′-h] fluorene in six steps starting from flourenone 4-carboxylic acid and 2,4-dichlorotoluene is described. As an intermediate product the 5, 13, 15-trioxo-derivative is obtained.     

Synthèse de flavones et de xanthones dans la série du benzo[4,5]thiophène

We describe the first synthesis of 2-arylbenzo[4,5]thieno-[2,3-b]pyran-4-one and of 2-arylbenzo [4,5] thieno [3,2-b] pyran-4-one, from benzo [4,5] thiophene and we have extended these cyclizations to obtain the heterocyclic analogs of the xanthones.     

Synthèses dans la série des bis-indéno-anthracènes,II [1] Le dihydro-9,16-bis-indéno[2.1-α; 1′,2′-c]anthracène

Starting from 3,3′-bi-indenyle and 1,4-naphthoquinone the title compound, III, has been synthesized in 3 steps (overall yield 54.6%).     

Synthèses dans ka série des bis-indéno-fluorènes II. Le dihydro-10,15-5H-bis-indéno [1, 2-a;2′,1′-i] fluorène

The biangular bis-indeno-fluorene 10,15-dihydro-5H-diindeno [l, 2-a; 2′, 1′-i]-fluorene (XII) has been synthesised in 6 steps starting from 1-(o-carboxyphenyl)-fluorenone (overall yield 21%). As an intermediate the 5,10,15-trioxoderivative of XII and, accessorily, its 5,10-dioxoderivative were also obtained.     

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.