Action de O- et N-nucléophiles sur les sels de phényl-3 benzopyrylium-1

3-Phenyl-1-benzopyrylium percholorates 1a, 1i react exculusively at C-2 with ethanol and isopropyl alcohol, affording mixed acetals 2a, 3a, 3i . Aqueous ammonia gives symmetrical secondary amines 4a, 4b or bis(3-phenyl-2H-1-benzopyran-2-yl)amines, while with aqueous aliphatic amines (40%) bis-acetals 5a, 5b or 2,2′-oxy-bis(3-phenyl-2H-1-benzopyrans) are characterized. In some other acidic conditions, 5a and 5b are also obtained.     

Enaminosucres et sucres halogénoacétyléniques. Communication préliminaire

Enamino- and Halogenoacetylenic sugars Traitment of an aldehydosugar ( 1 ) with secondary amines gave in an essentially quantitative yield the expected enamines ( 4–6 ). Chloro- and bromo-acetylenic sugars ( 11–14 ) were obtained in good yields by reacting with lithium methylphenylamide the corresponding gem-dihalo-olefinic sugars ( 7–10 ), whereas a Z-gem-fluoro-enamine ( 17 ) was formed when the difluoro-olefinic sugar 15 was submitted to the same reaction. The fluoro-enamine 17 is a useful synthetic intermediate allowing the preparation of several kinds of C-glycosylic compounds bearing heterocycles like isoxazole, chromone or coumarin.     

Synthése,stéréochimie,et réactivité thermique de (N-méthylidenealkylamino)-2 aziridines

1-Alkyl-2-(N-methylidenealkylamino)aziridines are obtained by the reaction of primary amines with either α-chloroacraldehyde or α-chlorocrotonaldehyde. Structural assignments are made by nmr spectroscopy. The thermal rearrangement of 1-alkyl-2-(N-methylidenealkylamino)-3-methylaziridines to pyrroles is described.     

Sels de N-alcoxyquinoléinium et d'isoquinoléinium porteurs d'une fonction cétone dans leur chaîne alcoxyle: Synthèse et réactivité vis-à-vis d'amines secondaires

Reaction of α-bromoisobutyrophenone on quinoline 1-oxide and isoquinoline 2-oxide in the presence of silver perchlorate leads to N-alkoxyquinolinium and isoquinolinium salts bearing a keto group in their alkoxyl chain. On treatment with secondary amines these salts are quantitatively converted to 2-benzoylquinoline and 1-benzoylisoquinoline. This conversion results from a decomposition analogous to the Katritzky mode A of the intermediate isoxazolo[2,3-a]quinolinium or isoquinolinium salts which are first formed by a Proton Abstraction Ring Closure sequence. These tricyclic intermediates have been isolated when 2,2,6,6-tetramethylpiperidine was used.     

Synthèse photochimique de biaryles et hétérobiaryles à partir d'aryl-et hétéroarylamines,d'un nitrite d'alkyle et d'un substrat aromatique ou hétéroaromatique

Photochemical synthesis of biaryls and heterobiaryls from aryl and heteroarylamines, alkylnitrite and aromatic or heteromatic substrates The photochemical reaction of aromatic and heteroaromatic amines with excess t-butyl nitrite in aromatic solvents (benzene, p-xylene, mesitylene) and in hetero-aromatic solvents (furan, thiophene) leads to biaryls or heterobiaryls. t-Butyl nitrite is more convenient than isopentyl nitrite which gives by-products. This new method has been used to synthesize 28 compounds in 17 to 60% yield.     

Synthese de bases de mannich acetyleniques cycliques

Terminal acetylenes can be converted in excellent yields into Mannich bases by reacting them with gem-aminoethers instead of formaldehyde and a secondary amine. This provides a possibility of preparing cyclic aminoacetylenes from w-acetylenic secondary amines, via the derived gem-aminoethers, using high dilution technique.     

Aza-2-diènes-1,3 4. Préparation et propriétés d'alkyl-1-pyrazone-imines et de leurs isomères

2-Aza-1,3-dienes. Synthesis and Properties of 1-Alkylpyrazone-imines and their Tautomers Treatment of 5-dialkylamino-1,1-dicyano-2-aza-1,3-dienes (or their 1-methoxycarbonyl analogoues) with primary amines gives substituted 1-alkyl-3-cyano-(or methoxycarbonyl-)pyrazoneimines. Tautomeric behaviour, nucleophilic addition to imino function and spectroscopic data of these isomers are examined.     

Amine-induced rearrangements of 2-bromo-1-(1H-indol-3-yl)-2-methyl-1-propanones: A new route to α-substituted indole-3-acetamides, β-substituted tryptamines, α-substituted indole-3-acetic acids and indole β-aminoketones

The reaction of 2-bromo-1-(1H-indol-3-yl)-2-methyl-1-propanone ( 1 ) and 2-bromo-1-(1-methyl-1H-indol-3-yl)-2-methyl-1-propanone ( 2 ) with primary amines proceeds in good yields to produce rearranged amides by a proposed pseudo-Favorskii mechanism. These amides in turn can either be reduced to produce β-substituted tryptamines or hydrolyzed to produce substituted indole-3-acetic acids. When the reaction is carried out using bulky primary or secondary amines, β-aminoketones are produced by elimination of hydrogen bromide followed by Michael addition. When hindered secondary amines or tertiary amines are used, elimination to the α,β-unsaturated ketones occurs.     

Acide 2-fluoro-2-phényl propanoïque: préparation et utilisation comme agent chiral de dérivation

The enantiomers of 2-fluoro-2-phenyl propanoic acid have been separated and theirabsolute configurations determined: the specific rotation of the acid with an R configurationis []²⁰_D= −28.5° (c = 1.5, ethanol). This acid has been used as a chiral derivatizingagent. Esters and amides prepared from this acid and chiral alcohols or amines presentimportant fluorine chemical shift differences between the diastereoisomers     

Selective Analysis of Secondary Amines Using Liquid Chromatography with Electrochemical Detection (LC‐EC)

In a mixture of primary and secondary aliphatic amines, the primary amines were derivatized (masked) with o‐phthalaldehyde (OPA) followed by derivatization of the remaining secondary amines with ferrocenecarboxylic acid chloride (FAC). The “tagged” amines were analyzed by LC‐EC (liquid chromatography with electrochemical detection) using in‐series dual electrode detection. Chemically‐reversible oxidation of the FAC tagged secondary amines and their subsequent complementary oxidation and reduction signals coupled with chemically‐irreversible oxidation of OPA tagged primary amines provided the selectivity for quantitative secondary amine analysis. The procedure was also applied for the selective identification of fragment 4–11 (N‐terminus‐proline) of Substance P in the presence of other Substance P fragments with primary amino acids as their N‐termini.     

Synthèse de 3,5-divinylidènepipéridines N-substituées à partir du 1,7-bis(triméthylsilyl)hepta-2,5-diyne et applications

The 1,7-bis(trimethylsilyl)hepta-2,5-diyne reacts with iminium ions generated in situ from primary alkyl- or primary functional amines by a double aminomethylation–desilylation process leading to N-substituted 3,5-divinylidenepiperidines.

Résumé

Le 1,7-bis(triméthylsilyl)hepta-2,5-diyne réagit avec les ions iminium générés in situ à partir d'alkylamines primaires ou d'amines primaires fonctionnelles pour conduire à des 3,5-divinylidènepipéridines N-substituées via un double processus d'aminométhylation–désilylation.     

Addition du chlorure de nitrosyle et de l'oxyde d'azote(III) sur l'allyltriméthylsilane et sur l'allylbenzyldiméthylsilane

Additions of Nitrosyl chloride and Dinitrogen trioxide to Allyltrimethylsilane and Allylbenzyldlmethylsilane. The reaction of nitrosyle chloride and dinitrogen trioxide with allyltrimethylsilane and allylbenzyldimethylsilane leads to nitrosochlorides and to pseudonitrosites. The structures of these compounds are proved by reduction to amines.     

Efficient synthesis of tertiary amines from secondary amines

Reliable N-alkylations of secondary amines have been developed. By using DIAD and TPP (or PS-TPP) a variety of secondary amines can be converted to the corresponding tertiary amines in good to excellent yields with diverse alkylhalides; no formation of quaternary amine salts are observed. These protocols are amenable to combinatorial chemistry libraries, and are also useful for the syntheses of secondary amines by an acid lysis of the cleavable tertiary amino resins.     

Transposition bis-homoallénylique: solvolyse de γ-tosylates alléniques

Cyclisation (formation of derivatives of 2-methylidene-cyclopentanol or cyclohexanone) with inversion of configuration and retention of optical activity is observed during the solvolysis of secondary γ-allenic tosylates. Steric factors rather than electronic ones control the participation of one of the double bonds in the allenic system. Kinetic results and product distribution are discussed.     

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.     

Synthèse de systèmes comportant deux cycles thiophéniques orthocondensés à un hétérocycle à sept chainons

The reduction of the carbonyl group of bithienyls carrying on each thiophene ring a formyl group bonded to the carbon atom next to the intercyclic bond leads to the expected primary di-alcohols. These dialcohols can give the corresponding bis-halogeno-methylated bithienyls. The dehydration of the alcohols and the action of sodium sulfide or amines upon the obtained halides leads respectively to the dihydrodithieno[c,e] oxepines, thiepines and azepines. The tetramethyl derivatives of the previous oxepines have been obtained from diacetylbithienyls.     

Etude du mécanisme de la réaction de hantzsch des thiazoles. I. Mise en évidence et détermination des produits intermédiaires et de dégradation

The Hantzsch thiazole synthesis from α-haloketones and thioamides, proceeds via intermediates that can be isolated under certain conditions. These have been identified, mainly by nmr spectroscopy, as thioimidate derivatives. The chain or cyclic structures of these compounds depend upon the nature of the substituents. Their dehydration gives together with the expected thiazole, secondary products which have also been isolated and identified as α-mercaptoketones and α-ketothiolesters.     

Un réactif défini de diazocopulation, le 3-phenyl 5-nitrosamino 1,2,4-thiodiazole ou phenitrazole

3-Phenyl-5-nitrosamino-1:2:4-thiodiazole, or phenitrazole, allows diazo coupling to be carried out in precisely defined conditions. In acid medium it dehydrates to a diazo compound which may be condensed directly with phenols or aromatic amines. The reagent enables the detection of aldehydes of which the corresponding phenylhydrazones lead to formazans. The colorations obtained allow the determination of amounts of the order of hundredths of a milligram.

Zusammenfassung

3-Phenyl-5-nitrosamino-1,2,4-thiodiazol (Phenitrazol) gestattet Diazokupplung unter genau definierten Bedingungen. In saurem Medium dehydriert die Verbindung zu einer Diazoverbindung, die direkt mit Phenolen oder aromatischen Aminen kondensieren kann. Das Reagens ermöglicht die Bestimmung von Aldehyden, deren entsprechende Phenylhydrazone zur Bildung von Formazanen führen. Die erhaltene Färbung gestattet die Bestimmung von Mengen in der Grössenordnung einiger Hundeertstel Milligramm.     

Préparation de phosphonates de sucres ramifiés par addition nucléophile conjuguée. Communication préliminaire

Preparation of unsaturated sugars phosphonates using nucleophilic conjugate addition Different types of phosphorus nucleophiles underwent conjugate addition reaction with one of the branched-chain sugars 4, 5 or 11 the addition taking place either on the endo or the exo face of the furanose ring (or on both faces in the case of 11 ). The configuration at C(3) of these new phosphorus-bearing types of sugars as well as the configuration at the phosphorus atom of the cyclic phosphinates 9 and 10 was established by NMR. (³J_P,H–C(2), ³J_P,C(1)). Small amounts (7%) of the spiro enol phosphonate 16 were formed when 11 reacted with trimethyl phosphite.     

Stéréochimie de β-diols et de leurs dérivés cycliques–VI. Calcul empirique des déplacements chimiques en série dioxannique. Détermination et discussion des incréments de calcul

In order to calculate empirically proton chemical shifts in methyl 1,3-dioxans, the basic values for each proton of 1,3-dioxan itself are estimated. Then, using methyl derivatives in the chair conformation, the Δδ primary effects of methyl groups in any position are given. Modifications take place in molecules with butane gauche interactions and these secondary effects are evaluated. Analogous Δδ in both the cyclohexane and dioxane series are related to similar cyclic geometry. The presence of oxygen atoms however, introduces important discrepancies.