Nouvelles voies d'accès à des aryl-4 thiéno[2,3-c]pyridines et à des aryl-7 thiéno[3,2-c]pyridines

4-Arylthieno[2,3-c]pyridines and 7-arylthieno[3,2-c]pyridines have been prepared by heating in polyphosphoric acid 2-(2-thenylamino>l-arylethanols or propanols and 2- 3-thenylamino>l-arylethanols or propanols, respectively.) Under the Beckmann rearrangement conditions, oximes of 4-aryl-4,5-dihydro-6H-cyclopenta[b]thiophen-6-one lead to 4-aryl-4,5- dihydro-6H-thieno[2,3-c]pyridin-7-one.     

Action de réactifs nucléophiles sur les phényl-5 thiéno[3,2-b]pyrannone-7 et phényl-2 benzo[b]thiéno[3,2-b]pyrannone-4

Reactions of 5-phenylthieno[3,2-b]pyran-7-one, 2-phenylbenzo[b]-thieno[3,2-b]pyran-4-one and the corresponding thiones with sodium ethylate, guanidines, hydrazines and amines are described and compared to those observed with benzopyranones.     

Sulfuric acid-promoted rearrangement of 3-(<Emphasis Type="Italic">N</Emphasis>-acylamino)-substituted caran-4-one oximes

The rearrangement of 3-(N-acylamino)-substituted caran-4-one oximes in the presence of sulfuric acid affords 2-oxa-4-azabicyclo[3.3.1]non-3-en-6-one derivatives. 3-Aminocaran-4-one oximes, in which the amino group contains such substituents as acetyl, propionyl, chloroacetyl, 1-adamantylcarbonyl, benzoyl, 2-thienylcarbonyl, or anilinocarbonyl, undergo this reaction. N-Acyl derivatives of higher fatty (heptanoic and nonadecanoic) acids do not undergo this reaction. The reaction with D₂SO₄ leads to the replacement of all hydrogen atoms of the isopropyl group by deuterium. The mechanism of this rearrangement is proposed. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1837–1844, August, 2005.     

Säurekatalysierte Umlagerung von 7-Hydroxy-royleanon in ein 20(10→9) abeo-Abietan-Derivat und zwei Phenalenone

Acid-catalyzed rearrangement of 7-hydroxyroyleanone into a 20(10→9) abeo-abietane derivative and two phenalenones Short treatment of either horminone ( 1b ), taxoquinone ( 1a ), 6,7-dehydroroyleanone ( 3 ) or 6β-hydroxyroyleanone ( 1c ) with 80% H₂SO₄ at 0° leads to a mixture of rearranged products. Two of the structures, determined by X-ray-cristallography, were found to be (9R, 10R)-20(10→9)-abeo-12-hydroxy-5,7, 12-abietatriene-11,14-dione ( 4 ) and 9-isopropyl-2,2,5-trimethyl-8H-phenaleno[1,9-bc]furan-8-one ( 5 ), and the third compound, isolated in very small amounts, has been provisionally identified as 3-hydroxy-9-isopropyl-2,2,5-trimethyl-8H-phenaleno[1,9-bc]furan-8-one ( 6 ) from the spectroscopic data.     

Phosphorus pentoxide in organic synthesis. XIX. Mixtures of phosphorus pentoxide and ortho-substituted arylamines as reagents in the synthesis of 9-aryl-9H-purin-6-amines

9-Aryl-9H-purin-6-amines 2 were readily obtained by heating 5-acetamido-4-amino-2-methylpyrimidin-6(1H)-one 1 in mixtures of phosphorus pentoxide, triethylamine hydrochloride and sterically hindered arylamines. Nonsterically hindered arylamines resulted in formation of 6-arylaminopurines 3. The mechanism for rearrangement of 2 into 3 is discussed.     

Propriétés de la benzopyranno[1][2,3-b]quinoxalinone-12

Under basic conditions. [1]benzopyrano[2,3-b]quioxakin-12-one leads to 3-(i-hydroxybenzoy1)-1H-quinoxalin-2-one. This ketone reacts with hydroxylamine and phenylhydrazine to give the expected derivatives or those of [1]benzopyrano92,3-b]quinoxalin-12-one. The reduction of [1]benzopyrano[2,3-b]quinoxalin-12-one was unsucessful by chemical means. However, electrochemical reduction leads to a dihydropyrazine nucleus.     

Thiényl- et séléniénylthiocyanates et sélénocyanates. 4. Synthèses de thiéno[2,3-d]thiazoles,de thiéno[2,3-e]thiazines et de quelques analogues sélénophéniques

Nucleophilic aromatic substitution of 3-bromo-2nitrothiophene and selenophene by thiocyanate and selenocyanate ions in dimethylsulfoxide yields 3-thienyl-and 3-selenienylthicoyanates and selenocyanates. After reduction of the nitro group, the amino derivatives undergo cyclizatrion to thieno[2,3-d]thiazoles and seleno [2,3-d]thiazoles. Also, 4H-2,3-dihydro-3-oxothieno[2,3-e]1,4-thiazine and its selenophene analog have been obtained.     

Reissert compound studies. XXXI. Emetine analogs based on the reaction of the reissert anion with 1,3,4,6,7,11b-hexahydro-9, 10-dimethoxybenzo[a] quinolizin-2-ones

Reaction of the Reissert anion with the carbonyl group of 1,3,4,6,7,11b-hexahydro-9,10-dimethoxybenzo[a]quinolizin-2-one and with 3-ethyl-1,2,3,4,6,7-hexahydro-9,10-dimethoxy-11bH-benzo[a]quinolizin-2-carboxaldehyde give emetine analogs. This anion does not react with the carbonyl group of 3-aIkyl-1,3,4,6,7,11b-hexahydro-9,10-dimethoxybenzo[a]quinolizin-2-one but instead gives a rearrangement product and the benzoquinolizinone cyanohydrin.     

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.     

Synthése par deux voies différentes d'un systéme dihétérocyclique apparenté aux peltogynoides

5-Oxo-5H,7H-[2]benzopyrano[4,3-b][1]benzopyran ( 2 ) has been synthesized from 3-(o-hydroxybenzylidene)isochroman-1,4-dione ( 3 ) by reductive cyclization, and from 5H,7H[2]benzo-pyrano[4,3-b][1]benzopyran-5,7-dione ( 4 ) by selective hydro-genation. This second method affords the dihydro compound 6 or 6a,12a-dihydro-5H,7H-[2]benzopyrano[4,3-b] [1 ]benzopyran-5-one as reaction time increases.     

Nouvelles synthèses de thiéno[3,2-c] - et thiéno[2,3-c]pyridines

A new method for the synthesis of thieno[2,3-c]-and [3,2-c]-pyridines and of their tetrahydro derivatives is described. The process is based on some modifications of the Pomeranz-Fritsch reaction leading to isoquinolines.     

Identification de stérols à chaîne latérale oxygénée dans une éponge de l'espèce Hyrtios

Thirty-two sterols are identified in the sponge Hyrtios sp. In addition to fourteen monohydroxylated compounds, the sterol fraction contains eight functionalized sidechain sterols, three of them new: 3 β-hydroxy-24-norchol-5-en-23-al (19) , (22-trans)-3 β-hydroxycholest-5, 22-dien-24-one (20) and (22R, 23R, 24S) or (22S, 23S, 24S)- 22,23-epoxy-24-methylchoest-5-en-3 β-ol (24). The probable biological origin, rather than artifact production, of these undescribed components is discussed.     

Analyse conformationnelle de cétones cyclopropaniques par RMN à l'aide des déplacements paramagnétiques induits par Eu(dpm)3

The lanthanide induced shifts (LIS) of the lanthanide shift reagent Eu(dpm)₃ are reported for several cyclopropyl ketones. The conformational preference of the cyclopropanoyl group is determined via LIS by comparison with two compounds: dispiro-[2.1.2.2]nonane-4-one and 4,4,5-trimethyl bicyclo[3.1.0]hexane 2-one which are respectively in s-cis and s-trans conformation.     

Photochemical reactions VII [1]. A ‘type A rearrangement’ in the photolysis of a steroidal α, β-unsaturated lactone

The irradiation of 17 β-hydroxy-2-oxa-androst-4-en-3-one ( 1 ) yield a cyclopropane derivative 2 , which is the result of a rearrangement, formally analogous to the ‘type A rearrangement’ of the enones. Two other products, the dihydroxy compound 5 and the dimer 6 , have also been isolated (Scheme 1).     

Säurekatalysierte Umlagerung von Allyl-cyclohexadienon-tosyl-hydrazonen: Beispiel einer Dienimin-Anilin-Umlagerung

The tosylhydrazones of 4-allyl- and 4-crotyl-4-methyl-cyclohexa-2, 5-dien-l-one ( 14 and 15 ) rearrange in the presence of acid to yield the corresponding 2-allyl- and 2-α-methylallyl-hydrazines 17 and 18 , respectively. A similar behaviour is shown by the tosylhydrazone of 2-allyl-2-methyl-cyclohexa-3, 5-dien-1-one ( 16 ). 16 could not be isolated. The observed acidcatalysed [3 s, 3 s]-sigmatropic rearrangement of the tosylhydrazones can be regarded as a rearrangement of the dienimine-aniline type.     

Etude du couplage 2J(N15?H) en série hétérocyclique. Application à la détermination des constantes d'équilibres prototropiques rapides

The fast tautomeric equilibrium of (N¹⁵)-4-phenylisoxazolin-5-one ( 2 ) has been investigated by a study of ²J(N¹⁵? H₃) coupling. Comparison of the observed values for 2 and for the two fixed forms (N¹⁵)-2-methyl-4-phenylisoxazolin-5-one ( 3 ) and (N¹⁵)-4-phenyl-5-methoxyisoxazol ( 4 ) indicates a considerable amount of enolic type structure for 2 in basic media.     

Etudes sur les composés organométalliques partie XX Sélectivité de l'addition 1,4 de composés benzyliques du titane IV avec la benzylidéneacétone

Studies of Organometallic Compounds, XX. Selectivity of 1,4-Addition of Benzyltitanium Compounds with Benzylildenacetone Tetrabenzyltitanium and dialkoxydibenzyltitanium compounds give essentially 1,4- addition with trans-4-phenyl-3-buten-2-one.     

Nitro derivatives of 1,3-dihydrobenzimidazol-2-one: II. Rearrangement of <Emphasis Type="Italic">N</Emphasis>-nitrobenzimidazol-2-ones

N-Nitrobenzimidazol-2-ones readily undergo rearrangement to C-nitro derivatives on heating in various solvents (ethyl acetate, butyl acetate, acetonitrile, acetone, dioxane, o-dichlorobenzene, anisole, acetic acid). This rearrangement was used to develop a procedure for the synthesis of 4,5,6,7-tetranitro-1,3-dihydrobenzimidazol-2-one in high yield (90–96%) by nitration of 1,3-dihydrobenzimidazol-2-one, as well as of 5,6-dinitro- and 4,5,6-trinitro-1,3-dihydrobenzimidazol-2-ones, with a small excess of concentrated nitric acid in a mixture with acetic anhydride and acetic acid at 50–60°C.     

Beckmann Fragmentation and Rearrangement. Part VI thian-3-one oximes. Fragmentation reactions no. 26

In 70% aqueous dioxane thian-3-one anti-oxime p-toluenesulfonate (tosylate) ( 8b ) undergoes concerted fragmentation to the methylidenesulfonium ion 14 , part of which recyclizes to 1,3-thiazepin-4-one ( 11 ). With the syn-isomer 8b rearrangement to 1,4-thiazepin-3-one ( 10 ) and fragmentation to 14 occur in the ratio 4:1. Analysis of the rate data in 80% ethanol shows that anti fragmentation is 142 times as fast as syn fragmentation, but only 26 times as fast as rearrangement of the ‘homomorphous’ thian-4-one oxime tosylate ( 18b ). A comparison of the rates of cyclohexanone oxime tosylate 20 , thian-3- and -4-one oxime tosylates reveals the rate retarding influence of sulfur. – The configurations assigned to the stereoisomeric thian-3-one oximes ( 8a ) in the literature have to be reversed in the light of present results.     

Identification de stérols à chaînes latérales courtes dans l′éponge Damiriana hawaiiana

Identification of short side chain sterols in the sponge Damiriana hawaiiana The steroidal composition of the sponge Damiriana hawaiiana is examined. Twenty-seven components are identified. In addition to the C₂₆-C₂₉, Δ⁵-mono and diunsaturated sterols, the sponge contains sterols without side-chain: androsta-5, 16-dien-3β-ol( 1 ), androst-5-en-3β-ol( 2 ); sterols with a non-functionalized side-chain consisting of two, three, four, five and six carbon atoms: pregna-5, 20-dien-3β-ol( 5 ), pregn-5-en-3β-ol( 6 ), 23, 24-bisnor-chola-5, 20-dien-3β-ol( 7 ), 23, 24-bisnor-chol-5-en-3β-ol( 8 ), 24-nor-chol-5-en-3β-ol( 10 ), chol-5-en-3β-ol( 11 ), 26, 27-bisnor-cholest-5-en-3β-ol( 12 ), and sterols possessing a short oxygenated side-chain such as 3β-hydroxy-androst-5-en-17-one( 3 ), androst-5-en-3β, 17β-diol( 4 ) and 3β-hydroxy-26, 27-bisnor-22-trans-cholesta-5, 22-dien-24-one( 14 ). The probable biological or dietary origin rather than artifact production of these hitherto undescribed components from marine sources is supported by their relatively high concentration and their relative proportions, both very different from those expected for autoxidation.