Nouvelle synthese de la tentoxine

We describe a new synthesis of tentoxine, cyclo(N-Me(L)Ala-(L)Leu-N-Me(ZΔ)Phe-Gly), with a direct introduction of the dehydro residue in the peptide chain. This method affords the linear tetrapeptide with a yield four times better than that given by the method of Rich.     

Nouvelle preparation du bis(trimethylsilyl)-1,3 propyne,intermediaire de synthese

The 1,3-bis(trimethylsilyl)propyne can be easily prepared by reductive silylation of HCCCH₂OR (R = Me, SiMe₃) by the Me₃SiCl/Li/THF reagent.     

Nouvelle synthese simple de nucleoside phosphorothiolate

The O,S-dimethylphosphorochloridate $\text{10}$ reacts with 5′-O-monomethoxytritylthymidine $\text{11}$ in pyridine giving nucleoside-3′-thiolophosphodiester $\text{13}$ in high yields; in acetonitrile and in the presence of 1-methylimidazole, this reaction leads to the nucleoside-3′-phosphotriester $\text{14}$ without formation of diester $\text{13}$. From the latter, the Tp and TpT have been prepared.     

Vinylallenes—VII: Nouvelle synthese de la dimethyl-3,11 nonacosanone-2, phermone sexuelle de la blatte germanique

A new synthesis of the titled pheromone is given ; it uses as the key step the Oxy-Cope reaction of a 4-ethynyl hexa-1,5-diene 3-ol.     

Contribution a la synthese de prostaglandines

A new general method for grafting the β chain of natural Prostaglandins and homologs is proposed.     

Nouvelle methode de synthese de tetrahydro-2,3,4,5 benzo (b) 1H-azepines substituees en position -2

Treatment of tertiary alcohols and trisubstituted olefins of the tetrahydronaphthalene series with the HN₃H₂SO₄ reagent leads directly and with good yields to a new class of compounds: the 3,4-dihydro 5H benzo (b) azepins substituted on position -2. The latter, on reduction, give the corresponding 2,3,4,5-tetrahydro 1H benzo (b) azepins, most of them being unknown in the literature. This work shows the high regiospecificity of this ring expansion reaction which can be explained by electronic and steric effects.     

Nouvelle synthese stereoselective de disels de botadiene-1,3 ylene-1,4 bisphosphoniums

A new way to 1,4 butadienylene bisphosphonium salts $\text{2}$ is given, using a base-catalyzed double isomerization process on acetylenic precursors $\text{3}$. The precursor can be synthetized by nucleophilic substitution of 1,4-diiodo 2-butyne with triphenylphosphine. The selection of the 1,4-dihalo 2-butyne has a strong influence on the course of the reaction which, besides that, can lead to exclusive formation of a new stabilized ylid-disalt $\text{5}$.The stereoselectivity of the t.butylamine induced double isomerization allows the isolation of the kinetic product, the (Z, E) 1,4-butadienylene bisphosphoniun salt, which is then readily converted into the more stable (E, E) isomer.     

Nouvelle synthese de trifluoromethylcetones et d' /ga-bromo trifluoromethylcetones

We report a new method for the preparation of trifluoromethylketones, as an alternative to the use of organometallics. The condensation of phosphonium ylides with trimethylsilyl trifluoroacetate provides silyloxy enol ethers whose hydrolysis leads to trifluoromethylketones. Bromation of the same silyloxy enol ether is also a convenient preparation of /ga-bromo trifluoromethylketone.     

Phosphates - II - sur la synthese thermique de l'orthophosphate de calcium et de sodium

Résumé Etude de la synthèse thermique de l'orthophosphate de calcium et de sodium pur en partant de six mélanges adéquats. Les réactions qui ont lieu pendant le chauffage des mélanges de synthèse ont été suivies par analyse thermique (TG et ATD). La succession des réactions qui ont lieu a été établie. On a trouvé à l'aide d'une série d'analyses physico-chimiques que CaNaPO₄ peut être obtenu à partir des six mélanges étudiés.

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The thermal synthesis of pure CaNaPO₄ was investigated starting from six mixtures. The reactions during the heating of the mixtures were monitored by means of thermal analysis (TG and DTA). The sequence of reactions was established. Based on a number of physical and chemical determinations it was found that CaNaPO₄ may be obtained from all six mixtures.

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Zusammenfassung Die thermischen Synthesen der reinen Calcium- und Natrium-Orthophosphate aus sechs entsprechenden Gemischen wurden untersucht. Die sich bei dem Erhitzen der Synthesegemische abspielenden Reaktionen wurden mittels Thermoanalyse (TG und DTA) verfolgt. Die Reihenfolge der ablaufenden Reaktionen wurde bestimmt. Mittels einer Reihe von physikalisch-chemischen Analysen wurde festgestellt, daß CaNaPO₄ aus den sechs studierten Gemischen erhalten werden kann.

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CaNaPO₄ . , , ( ). . , CaNaPO₄ .

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Phosphates - I - Rev. Roum. de Chimie 11 (1966) 725.     

Nouvelle synthese simple de deoxtribonucledside-3′-aryl-β-cyanoethyl-phosphates

The deoxyribonucleoside-3′-aryl-β-cyanoethyl-phosphates, very used in the synthesis of oligodeoxynucleotides, were synthesized in high yields in a single step from the nucleoside derivatives with a monofunctional phosphorylating agent : cyclohexylammonium p-chlorophenyl-β-cyanoethyl-phosphate.     

Etude de la synthese des zeolites 4A et HS a partir de produits naturels

The crystallization of the zeolite HS was studied during the synthesis of the zeolite 4A using several raw materials like diatomite, kaolin and bentonite. First, these three materials were activated mainly by melting in the presence of caustic soda. The comparison with the pure reagents (solution of sodium silicate and sodium aluminate) as a reference allowed to deduce that an appearance of the zeolite HS during the synthesis is observed with most of the raw materials. Its formation takes place when the concentration of aluminium decreases below the value corresponding to the pure products in the liquid phase. This situation takes place when the reactant gel is heterogeneous, which is characteristic of all the raw materials studied. This seems to be the reason for the formation of zeolite HS.