- Cyclocondensation of 2-aminobenzimidazole with dimedone and its arylidene derivatives
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The reactions of 2-aminobenzimidazole with substituted benzaldehydes and dimedone, 2-arylidene derivatives of dimedone, 9-arylhexahydro-1H-xanthene-1,8(2H)-diones and also with dimedone and DMF have been studied. The direction of formation of the pyrimidine ring has been established and discussed. An X-ray structural investigation of 2,2-dimethyl-2,3-dihydrobenzimidazo[1,2-a]quinazolin-4(1H)-one has has been carried out.
- Lipson,Desenko,Shishkina,Shirobokova,Shishkin,Orlov
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Read Online
- Two phases of C9H12O4: Why is the structure at 295 K so complicated?
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Molecules of 4,4′-dimethyl-2-hydroxy-6-oxocyclohexene-1-carboxylic acid, C9H12O4, crystallize at 295 K in a modulated superstructure with five half-molecules in the asymmetric unit; each molecule is located on one of the mirror planes of the space group Cmc21. Reflections with k ≠ 5n are systematically weak; a satisfactory refinement can be obtained in a Cmcm pseudocell having b′ = b/5. The important modulation involves small rotations of the molecules around axes perpendicular to the mirror plane; there is also an up/down disorder of the CMe2 fragment in four of the five molecules (two molecules with occupancy factors ca 4:1; two with occupancy factors ca 3:2). The modulation is a response to packing problems that can be traced to the differences between the thin, electron-and oxygen-rich 'head' of the molecule and the thicker, methyl-rich 'tail'. At 130 K the length of b is reduced by 2/5 and the Pmnb structure is ordered. Both structures can be described as modulated variants of the Cmcm substructure; the wavevectors are 2b′*/5 for the room-temperature structure and b′*/2 for the low-temperature structure, where b′* is the reciprocal axis of the subcell. The structure at room temperature can also be understood as a hybrid of the fully disordered pseudocell structure and the ordered structure that is found at low temperature.
- Duncan, Laura L.,Patrick, Brian O.,Brock, Carolyn Pratt
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- Rapid and Multigram Synthesis of Vinylogous Esters under Continuous Flow: An Access to Transetherification and Reverse Reaction of Vinylogous Esters
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An environmentally benign approach for the synthesis of vinylogous esters from 1,3-diketone and its reverse reaction under continuous-flow has been developed with alcohols in the presence of inexpensive Amberlyst-15 as a catalyst. This methodology is highly selective and general for a range of cyclic 1,3-dicarbonyl compounds which gives a library of linear alkylated and arylated vinylogous esters in good to excellent yield under solvent and metal free condition. Furthermore, the long-time experiment in a continuous-flow up to 40 h afforded 8.0 g of the vinylogous ester with turnover number (TON) = 28.6 and turnover frequency (TOF) = 0.715 h-1 using Amberlyst-15 as a catalyst. Furthermore, a continuous-flow sequential transetherification of vinylogous esters with various alcohols has been achieved in high yield. Reversibly, this vinylogous ester was deprotected or hydrolyzed into ketone using environmentally benign water as a solvent and Amberlyst-15 as a catalyst under continuous-flow process.
- Mohanta, Nirmala,Chaudhari, Moreshwar B.,Digrawal, Naveen Kumar,Gnanaprakasam, Boopathy
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p. 1034 - 1045
(2019/05/24)
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- Zinc chloride catalyzed collective synthesis of arylmethylene bis(3-hydroxy-2-cyclohexene-1-ones) and 1,8-dioxo-octahydroxanthene/acridine derivatives
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Catalytic amount of ZnCl2 efficiently promoted rapid synthesis of arylmethylene bis(3-hydroxy-2-cyclohexene-1-one) in water at room temperature in excellent yield. At elevated temperature, ZnCl2 also catalyzed one-pot synthesis of 1,8-dioxo-octahydroxanthene and 1,8-dioxo-decahydroacridine derivatives in good yield. In specific instances, unusual dissociation of dimedone from the arylmethylene bis(3-hydroxy-2-cyclohexene-1-one) was identified in the reaction medium. It was minimized/avoided by the addition of known excess dimedone to the reaction mixture in the one-pot synthesis of 1,8-dioxo-octahydroxanthene.
- Ganesan, Subramaniapillai Selva,Kothandapani, Jagatheeswaran,Ganesan, Asaithampi
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p. 682 - 687
(2015/04/14)
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- Synthesis of 10-amino-9-aryl-2,3,4,5,6,7,9,10-octahydroacridine- 1,8-dione derivatives
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A series of novel 10-amino-9-aryl-2,3,4,5,6,7,9,10-octahydroacridine-1,8- dione derivatives 4 were synthesized by hydrazine or phenylhydrazine and 9-aryl-1,8-dioxo-2,3,4,5,6,7,9-heptahydroxanthene derivatives 3, which were prepared by 5-substituted-1,3-cyclohexanedione 1 and aromatic aldehydes 2 in the presence of concentrated H2SO4 as a catalyst in water. The structures of all compounds were characterized by IR, MS, 1H-NMR, and elemental analysis, and the title compounds possess good fluorescence properties..
- Han, Guang-Fan,Cui, Bin,Chen, Li-Zhuang,Hu, Xiao-Lei
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scheme or table
p. 195 - 199
(2012/04/17)
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- Synthesis of enaminones in aqueous media using catalytic dilute HCl
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(Chemical Equation Presented) A green and convenient approach to the synthesis of β-enaminones from aromatic amines and 5-substituted-1,3- cyclohexanedione in the presence of dilute hydrochloric acid (30 mmol=L) as a catalyst in solvent-free media is described. This method provides several advantages such as environmental friendliness, low cost, good yields, and simple workup procedure. Copyright Taylor & Francis Group, LLC.
- Cui, Bin,Wang, Rui-Hua,Chen, Li-Zhuang,Jin, Yan,Han, Guang-Fan
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scheme or table
p. 1064 - 1070
(2011/04/26)
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- Cerium(IV) ammonium nitrate-catalyzed synthesis of β-keto enol ethers from cyclic β-diketones and their deprotection
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A mild and efficient method for etherification of cyclic β-diketones with alcohols has been developed using a catalytic amount of cerium(IV) ammonium nitrate at room temperature to afford the corresponding β-keto enol ethers in good to excellent yields. The deprotections of enol ethers in water-acetonitrile (1:1) using a catalytic amount (10 mol %) of cerium(IV) ammonium nitrate have also been achieved. Copyright
- Banerjee, Biplab,Mandal, Samir Kumar,Roy, Subhas Chandra
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- Microemulsion-templated synthesis of carbon nanotube-supported Pd and Rh nanoparticles for catalytic applications
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Palladium, rhodium, and bimetallic Pd/Rh nanoparticles synthesized in a water-in-hexane microemulsion can be deposited directly on surfaces of functionalized multiwalled carbon nanotubes with high yields. The CNT-supported Pd nanoparticles are active catalysts for hydrogenation of olefins, for carbon-carbon bond formation, and for carbon-oxygen bond cleavage reactions. The CNT-supported Rh nanoparticles are active catalysts for hydrogenation of arenes, and the CNT-supported bimetallic Pd/Rh nanoparticles show an unusually high catalytic activity for hydrogenation of anthracene. This simple and novel synthetic technique for making CNT-supported monometallic and bimetallic nanoparticles may have a wide range of catalytic applications for chemical syntheses. Copyright
- Yoon, Byunghoon,Wai, Chien M.
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p. 17174 - 17175
(2007/10/03)
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- Synthesis of partially hydrogenated 1,2,4-triazoloquinazolines by condensation of 3,5-diamino-1,2,4-triazole with aromatic aldehydes and dimedone
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Three-component condensation of 3,5-diamino-1,2,4-triazole with aromatic aldehydes and dimedone in dimethylformamide gives 2-amino-5-aryl-8,8-dimethyl-5, 6,7,8,9,10-hexahydro[1,2,4]triazolo[3,2-b]quinazolin-6-ones. The reaction of 3,5-diamino-1,2,4-triazole with dimedone in the absence of aldehyde involves dimethylformamide as one of the carbonyl components to afford 2-amino-8,8-dimethyl-6,7,8,9-tetrahydro[1,2,4]triazolo[2,3-a]quinazolin-6-one. 2005 Pleiades Publishing, Inc.
- Lipson,Desenko,Borodina,Shirobokova,Musatov
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p. 114 - 119
(2007/10/03)
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- 2,3,6,7,8,9-hexahydro-8,8-dimethyl-5-phenyl-1H-1,4-benzodiazepin-6-one
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Several approaches for the synthesis of the title compound 1 were investigated. Treatment of the ethane-1,2-diamine derivative 2 with phosphoryl chloride afforded 3-chloro-5,5-dimethylcyclohex-2-enone (3) and 1-(5,5-dimethyl-3-oxocyclohex-1-enyl)-4,5-dihydro-2-phenylimidazole (4). The reaction of 2-benzoyldimedone (5) with an equimolar amount of ethane-1,2-diamine led to the 2:1 adduct 6, whereas with an excess of ethane-1,2-diamine, 4,5-dihydro-2-phenylimidazole (7) and dimedone were obtained. The synthesis of the title compound 1 was achieved by reacting 2-benzoyl-3-chloro-5,5-dimethylcyclohex-2-enone (8) with ethane-1,2-diamine.
- Egg,Knauseder,Mayr,Schopf
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p. 655 - 657
(2007/10/02)
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- On the Reaction of Vinyl Isocyanates with Enamines
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Vinyl isocyanate reacts with enamines to give N-vinyl carboxamides which, unlike the more highly substituted analogues, do not cyclize readily to 2-pyridones.
- Prager, Rolf H.,Were, Stephen T.
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p. 1635 - 1641
(2007/10/02)
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- Mechanism of hydrolysis and structure-stability relationship of enaminones as potential prodrugs of model primary amines
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The objective of this work was to investigate the chemistry and the structure-stability relationship of enaminones (a class of enamines formed between a primary amine and a 1,3-dicarbonyl compound) and to evaluate their potential usefulness as prodrugs of primary amines. The acid-catalyzed degradation of the enaminones was found to be very sensitive to minor differences in the structure of the 1,3-dicarbonyl compound used to form the enaminone, but relatively insensitive to changes in the amine portion of the enaminones. A correlation was found between the rate of enaminone hydrolysis and the pK(a) of the 1,3-dicarbonyl compound, suggesting that the rate-controlling step in the hydrolysis of the enaminones was the proton addition to the vinyl carbon of the enaminone. Enaminones formed with cyclic 1,3-dicarbonyl compounds were significantly more stable than those formed with structurally similar acyclic compounds. Based on chemical stability considerations alone, enaminones do not appear to be good candidates as prodrugs of primary amines. Evidence is presented, however, that enaminones formed between amines and 1,3-ketoesters or lactones may be subject to enzyme-catalyzed degradation. Further research on the design of enaminones destabilized by a triggering enzymatic event that results in the loss of conjugation (e.g., ester or lactone hydrolysis or an oxidation/reduction event) may prove worth pursuing.
- Naringrekar,Stella
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p. 138 - 146
(2007/10/02)
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- Carbenoid Type Reactions of a Stabilized Bismuthonium Ylide in the Presence of Copper Catalyst
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Triphenylbismuthonio-4,4-dimethyl-2,6-dioxocyclohexan-1-ide reacts with 1-alkynes in the presence of small amounts of copper(I) chloride to form bicyclic furan derivatives probably via a carbenoid intermediate.
- Ogawa, Takuji,Murafuji, Toshihiro,Iwata, Kazuhiko,Suzuki, Hitomi
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p. 325 - 328
(2007/10/02)
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- Enamine quaternary compounds, methods of making and their use as muscle relaxants
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Disclosed are novel enamine quaternary compounds of the formula STR1 wherein m=1, 2 or 3 and n=1, 2 or 3 with the proviso that m+n=3, 4 or 5; R1 and R2 are independently lower alkyl or hydrogen, and R3 and R4 are independently selected from the group consisting of lower alkyl, lower cycloalkyl lower alkyl, lower alkenyl, phenyl lower alkyl, thienyl lower alkyl, furyl lower alkyl, lower alkoxy lower alkyl, halogenated lower alkyl, lower alkyloyloxo or lower alkyloyloxy lower alkyl or wherein NR3 R4 together comprise a heterocycle ring; and wherein X- represents a pharmaceutically acceptable anion. Pharmaceutical compositions containing the same when administered to warm-blooded animals exhibit a muscle relaxant effect characterized by excellent onset and recovery times. Also disclosed are methods of making the enamine quaternary compounds.
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- Process for the preparation of 3-alkyl-substituted glutaric acids and 2-alkyl-substituted succinic acids
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This invention relates to a novel method of preparing 3-alkyl-substituted glutaric acids and 2-alkyl-substituted succinic acids from 5-alkyl-substituted-1,3-cyclohexane-diones or 3-alkyl-substituted-5-ketohexanoic acids via transition-metal catalyzed oxidation.
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- Biosynthesis of Sulfur Compounds. Investigations of the Biosinthesis of Asparagusic Acid.
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Investigations of the biosynthesis of the naturally occuring 1,2-dithiolane asparagusic acid (1) in Asparagus officinalis have shovn that the substance is derived from inobutyric acid via the intermediacy of methacrylic acid, 2-methyl-3-mercaptopropionic acid, and S-(2-carboxy-n-propyl) cysteine.The conversion of isobutyric acid to methacrylic acid in Asparagus has also been shown to proceed by oxidation of the 2-pro-S methyl group of isobutyrate.Finally, the absolute configuration of naturally occuring S-(2-carboxy-n-propyl)cysteine has been determined.
- Parry, Ronald J.,Mizusawa, A.E.,Chiu, I.C.,Naidu, M.V.,Ricciardone, M.
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p. 2512 - 2521
(2007/10/02)
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- Solvent Effects on Keto-Enol Equilibria: Tests of Quantitative Models
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The effect of solvent on the equilibrium constants between selected keto-enol isomer pairs has been determined.The protomeric systems studied are 5,5-dimethyl-1,3-cyclohexanedione (1), 2-methyl-1,3-cyclohexanedione (3), 3-oxabicyclo-2,9-dioxononane (5), 2,4-pentanedione (7), ethyl 3-oxobutanoate (9), and 9-anthracenone (11).A wide variety of theoretical and empirical solvation parameters have been tested in a multiparameter linear free energy format to model the changes in equilibria.The most successful correlations are obtained with the Kamlet-Taft polarity-polarizability and hydrogen-bonding terms, although the Swain A and B factors have advantages in same cases.In general, for the isomer pairs in which the enol cannot form an internal hydrogen bond (1-2, 3-4, and 11-12), the equilibria appear to be controlled almost completely by the hydrogen-bonding basicity of the solvent.For the isomer pairs 5-6, 7-8, and 9-10, in which intramolecular hydrogen bonding is possible, the polarity-polarizability effect dominates, although differential stabilization of the isomers by hydrogen bonding remains significant.
- Mills, Sander G.,Beak, Peter
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p. 1216 - 1224
(2007/10/02)
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- α,β-UNSATURATED THIO COMPOUNDS. XV. PROTONATION AND HYDROLYSIS OF 3-AMINO-2-CYCLOHEXENE-1-THIONES AND 3-AMINO-1-INDENETHIONES
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The protonation and acid hydrolysis of 3-amino-2-cyclohexene-1-thiones and 3-amino-1-indenethiones were investigated from the standpoint of the principle of hard and soft acids and bases.A relationship was established between the direction of hydrolysis of the thioketones and the nature of their protonation.
- Timokhina, L. V.,Usov, V. A.,Lavlinskaya, L. I.,Voronkov, M. G.
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p. 108 - 112
(2007/10/02)
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- Process for the production of dimedone
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Process for the production of dimedone from isophorone. The isophorone is converted in the presence of a solvent with ozone into an ozone-addition product. An alcohol corresponding to the ester radical is added at the latest after the formation of the ozone-addition product for the formation of the intermediate product, 3,3-dimethyl-5-oxo-hexanoic acid ester. The ozone addition product is heated in the presence of acids to a temperature of 20° to 150° C. The 3,3-dimethyl-5-oxo-hexanoic acid ester is isolated thereby. The ester is then converted in a further step into dimedone by treatment of the ester with an alkali alcoholate in an anhydrous milieu.
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- REACTION OF 2-ACETYL-2-CYCLOALKEN-1-ONES WITH CYCLIC β-DIKETONES
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The corresponding 2-acetyl-1,3-cyclohexadien-1-ols were obtained by the reduction of 2-acetyl-3-chloro-2-cyclohexen-1-one and 2-acetyl-3-chloro-5,5-dimethyl-2-cyclohexen-1-one with zinc activated by silver acetate.They were studied in the Michael addition reaction with dimedone and 1,3-cyclohexanedione in the presence of sodium methoxide.It was concluded that the transformation of these 2-acetyl-2-cyclohexen-1-ones into the corresponding 2-acetyl-1,3-cyclohexadien-1-ols is reversible.By dehydration of the Michael addition adducts and reaction with ammonia tricycliccompounds with an additional pyran or dihydropyridine ring were obtained.
- Akhrem, A. A.,Lakhvich, F. A.,Pyrko, A. N.
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p. 2027 - 2033
(2007/10/02)
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- AN EASY SYNTHESIS OF MONOMETHYL MALONATE DERIVATIVES
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Monomethyl malonates (IIIa-c and Va) were synthesized from Meldrum's acid (Ia) by treating with an excess of diazomethane in the corresponding alcohols and piperidine, respectively, in quantitative yields.In a similar manner, 5-p-chlorobenzyl Meldrum's acid (Ib) afforded the corresponding monomethyl malonate derivatives (IIIe, f, and Vb).The mechanism proposed for this reaction is described.KEYWORDS - Meldrum's acid; monomethyl malonate; half ester; ketene ester; 4,6-dioxo-1,3-dioxane
- Matoba, Katsuhide,Yamazaki, Takao
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p. 2955 - 2956
(2007/10/02)
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- Method for making keto acids and dione cyclics obtained therefrom
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A method is provided for oxidatively cleaving α,β-unsaturated cyclic ketones, such as isophorone, with an oxidizing agent, for example, ozone, and thereafter recovering the resulting keto acid. In instances where ozone is used, an aqueous hydroperoxide and phase transfer catalyst can be used to recover the keto acid. Dione cyclics, for example, dimedone, can be obtained by direct dehydration of the keto acid.
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- SYNTHESIS AND PROPERTIES OF 2-DIAZO-1,3-DICARBONYL COMPOUNDS. V. SYNTHESIS AND 1,2-NUCLEOPHILIC REARRANGEMENTS OF SOME 2-DIAZO-3-HYDROXY-1-CYCLOHEXANONES
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2-Diazo-3-hydroxy, 2-diazo-3-hydroxy-5,5-dimethyl, and 2-diazo-3-hydroxy-4,4,6,6-tetramethyl-1-cyclohexanones were obtained by reduction of 2-diazo 1,3-diketones of the cyclohexane series, and their spectral characteristics were determined.Photolytic, catalytic, and thermal elimination of nitrogen in these diazo compounds is only accompanied by 1,2-nucleophilic rearrangements.During photolysis of the diazohydroxycyclohexanones in an aqueous medium the main reaction path is a Wolff rearrangement, i.e., ring contraction with the formation of hydroxy and unsaturated acids of the cyclopentane series and some of their derivatives.Acid decomposition of the diazohydroxycyclohexanones leads mainly to an alkyl shift as a result of which (hydroxymethylene)cyclopentanones are formed with ring contraction.
- Nikolaev, V. A.,Zhdanova, O. V.,Korobitsyna, I. K.
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p. 488 - 498
(2007/10/02)
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- Introduction of Oxygen Functions into the α-Position of β-Diketone, 4. Direct Acyloxylation of 1,3-Cyclohexanediones by Diacyl Peroxides
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Direct acyloxylation of 1,3-cyclohexanediones 1 leads only by way of exception to the formation of monoacyloxylated products 4.However, their sodium salts 5 yield exclusively the immediate reaction products 8 of a bisacyloxylation.On the other hand, these products are unstable in the presence of base, and they experience a migration of an acyl group and loss of one mol of carboxylic acid yielding cyclohexadienones 9.The mechanism of this new rearrangement is described.Starting from products of a benzyloxycarbonyloxylation a convenient synthesis of reductones is described.
- Schank, Kurt,Blattner, Rudolf,Schmidt, Volker,Hasenfratz, Hermann
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p. 1938 - 1950
(2007/10/02)
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- 146. Retro-Aldol Reaction of Retinylidene-1,3-Diketones; Correlation with Biological Activity
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Retro-Aldol reaction of retinylidene-dimedone is reported.
- Acton, Nancy,Brossi, Arnold
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p. 1396 - 1399
(2007/10/02)
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