- Radical cyclisation onto nitriles
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Iminyl radicals, generated by 5-exo cyclisation of alkyl, vinyl and aryl C-centred radicals onto nitriles, undergo β-scission (nitrile translocation), reduction or tandem cyclisation onto alkenes depending on the nature of the α-substituent. 5-exo Cyclisations of aryl radicals onto nitriles undergo nitrile translocation when the α-substituent is CN, CO2R, SO2Ph or CONMe2. The rate of translocation is faster than 5- or 6-exo cyclisation onto alkenes or 1,5-hydrogen abstraction of allylic hydrogens. When the α-substituents are alkyl, the intermediate iminyl radicals do not undergo nitrile translocation. (C) 2000 Elsevier Science Ltd.
- Bowman,Bridge,Brookes
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Read Online
- The generation of aryl anions by double electron transfer to aryl iodides from a neutral ground-state organic super-electron donor
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(Chemical Equation Presented) It takes two to cyclize: Aryl halides are reduced to aryl anions by double electron transfer from the neutral ground-state electron donor 1 (see scheme), as shown by the formation of a cyclic ketone (2). The reduced compound (3) is also formed. Calculations show that the loss of two electrons from 1 is both thermodynamically and kinetically viable and generates a more planar resonance-stabilized structure.
- Murphy, John A.,Zhou, Sheng-Ze,Thomson, Douglas W.,Schoenebeck, Franziska,Mahesh, Mohan,Park, Stuart R.,Tuttle, Tell,Berlouis, Leonard E. A.
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Read Online
- One-pot reduction of aryl iodides using 4-DMAP methiodide salt
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An efficient one-pot procedure is described for the reduction of aryl iodides to aryl anions using a structurally simple bis-pyridinylidene electron donor, prepared in situ by treating 4-DMAP methiodide salt with base. The results show (i) that pyridinylidene carbenes can be easily used for intermolecular C-C bond formation, (ii) that bis-pyridinylidenes demonstrate superior robustness compared to electron-donor systems based on bis-imidazolylidenes, and (iii) that electron-donor strength is enhanced in the simplified DMAP-based donor. Deuterated analogues of this donor also provide mechanistic information on the source of protons when the aryl anions are quenched in situ. Georg Thieme Verlag Stuttgart.
- Garnier, Jean,Murphy, John A.,Zhou, Sheng-Ze,Turner, Andrew T.
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- Process chemistry related to the experimental rice herbicide 2,2-dimethyl-1-(4-methylthio-5-pyrimidinyl)indane
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Two concise syntheses of the experimental rice herbicide 2,2-dimethyl-1-(4-methylthio-5-pyrimidinyl)indane are reported. The initial synthesis relies on a low-temperature addition of 5-lithio-4-methylthiopyrimidine to 2,2-dimethyl-1-indanone to construct the pyrimidinylindane system. Process improvements to this route are described and resulted in the preparation of 90 kg of the title compound on pilot plant scale. Economics dictated the need to identify a new synthetic route which utilized inexpensive raw materials. Detailed herein is the initial discovery of a new route which features a novel combination of dissolving metal reduction/formylation/cyclization to construct the requisite pyrimidine ring. Process improvements to this chemistry have allowed us to deliver an appropriately substituted pyrimidinylindane in a minimal number of synthetic operations.
- Dietsche, Thomas J.,Gorman, David B.,Orvik, Jon A.,Roth, Gary A.,Shiang, William R.
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Read Online
- Sulfur-Based Intramolecular Hydrogen-Bond: Excited-State Hydrogen-Bond On/Off Switch with Dual Room-Temperature Phosphorescence
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We report O-H-S hydrogen-bond (H-bond) formation and its excited-state intramolecular H-bond on/off reaction unveiled by room-temperature phosphorescence (RTP). In this seminal work, this phenomenon is demonstrated with 7-hydroxy-2,2-dimethyl-2,3-dihydro-1H-indene-1-thione (DM-7HIT), which possesses a strong polar (hydroxy)-dispersive (thione) type H-bond. Upon excitation, DM-7HIT exhibits anomalous dual RTP with maxima at 550 and 685 nm. This study found that the lowest lying excited state (S1) of DM-7HIT is a sulfur nonbonding (n) to π? transition, which undergoes O-H bond flipping from S1(nπ*) to the non-H-bonded S′1(nπ*) state, followed by intersystem crossing and internal conversion to populate the T′1(nπ*) state. Fast H-bond on/off switching then takes place between T′1(nπ*) and T1(nπ*), forming a pre-equilibrium that affords both the T′1(nπ*, 685 nm) and T1(nπ*, 550 nm) RTP. The generality of the sulfur H-bond on/off switching mechanism, dubbed a molecule wiper, was rigorously evaluated with a variety of other H-bonded thiones, and these results open a new chapter in the chemistry of hydrogen bonds.
- Liu, Zong-Ying,Hu, Jiun-Wei,Huang, Chun-Hao,Huang, Teng-Hsing,Chen, Deng-Gao,Ho, Ssu-Yu,Chen, Kew-Yu,Li, Elise Y.,Chou, Pi-Tai
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Read Online
- Enantioselective Synthesis of Indanes with a Quaternary Stereocenter via Diastereoselective C(sp3)-H Functionalization
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A practical synthesis of enantioenriched indane derivatives with quaternary stereocenters was developed via sequential enantioselective reduction and C-H functionalization. Good to excellent enantioselectivity could be achieved by either the CuH-catalyzed asymmetric reduction or the Corey-Bakshi-Shibata (CBS) reduction of indanone derivatives. The subsequent diastereospecific and regioselective rhodium-catalyzed silylation of the methyl C-H bond led to indane derivatives with quaternary centers. This strategy was further applied in syntheses of (nor)illudalane and botryane sesquiterpenoids.
- Chen, Jun,Shi, Zhan,Lu, Ping
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supporting information
p. 7359 - 7363
(2021/10/01)
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- Nickel-Catalyzed Domino Heck-Type Reactions Using Methyl Esters as Cross-Coupling Electrophiles
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While esters are frequently used as traditional electrophiles in substitution chemistry, their application in cross-coupling chemistry is still in its infancy. This work demonstrates that methyl esters can be used as coupling electrophiles in Ni-catalyzed Heck-type reactions through the challenging cleavage of the C(acyl)?O bond under relatively mild reaction conditions at either 80 or 100 °C. With the σ-NiII intermediate generated from the insertion of acyl NiII species into the tethered C=C bond, carbonyl-retentive products were formed by domino Heck/Suzuki–Miyaura coupling and Heck/reduction pathways when organoboron and mild hydride nucleophiles are used.
- Zheng, Yan-Long,Newman, Stephen G.
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supporting information
p. 18159 - 18164
(2019/11/13)
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- CXCR3 RECEPTOR AGONISTS
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Compounds are provided having the structure of the following Formula I: where R, R1, R2, R3a and R3b are as defined herein. Pharmaceutical compositions comprising such compounds, as well as methods related to their manufacture and use, are also provided.
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Paragraph 325
(2018/03/25)
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- Potent Inhibitors of Plasmodial Serine Hydroxymethyltransferase (SHMT) Featuring a Spirocyclic Scaffold
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With the discovery that serine hydroxymethyltransferase (SHMT) is a druggable target for antimalarials, the aim of this study was to design novel inhibitors of this key enzyme in the folate biosynthesis cycle. Herein, 19 novel spirocyclic ligands based on
- Schwertz, Geoffrey,Witschel, Matthias C.,Rottmann, Matthias,Leartsakulpanich, Ubolsree,Chitnumsub, Penchit,Jaruwat, Aritsara,Amornwatcharapong, Watcharee,Ittarat, Wanwipa,Sch?fer, Anja,Aponte, Raphael A.,Trapp, Nils,Chaiyen, Pimchai,Diederich, Fran?ois
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supporting information
p. 931 - 943
(2018/04/20)
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- Silylative Kinetic Resolution of Racemic 1-Indanol Derivatives Catalyzed by Chiral Guanidine
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Efficient kinetic resolution of racemic 1-indanol derivatives was achieved using triphenylchlorosilane by asymmetric silylation in the presence of chiral guanidine catalysts. The chiral guanidine catalyst (R,R)-N-(1-(β-naphthyl)ethyl)benzoguanidine was found to be highly efficient as only 0.5 mol % catalyst loading was sufficient to catalyze the reaction of various substrates with appropriate conversion and high s-values (up to 89). This catalyst system was successfully applied to the gram-scale silylative kinetic resolution of racemic 1-indanol with high selectivity.
- Yoshimatsu, Shuhei,Yamada, Akira,Nakata, Kenya
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p. 452 - 458
(2018/02/19)
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- DUAL NAV1.2/5HT2A INHIBITORS FOR TREATING CNS DISORDERS
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Compounds of formula I: I are disclosed, as are pharmaceutical compositions containing such compounds. Methods of treating neurological or psychiatric disorders in a patient in need are also disclosed. Such disorders include depression, bipolar disorder, pain, schizophrenia, obsessive compulsive disorder, addiction, social disorder, attention deficit hyperactivity disorder, an anxiety disorder, autism, a cognitive impairment, or a neuropsychiatric symptom such as apathy, depression, anxiety, psychosis, aggression, agitation, impulse control disorders, and sleep disorders in neurological disorders such as Alzheimer's and Parkinson's diseases.
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Paragraph 0126
(2018/03/28)
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- Hydrogen Atom Transfer-Mediated Cyclisations of Nitriles
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Hydrogen atom transfer-mediated intramolecular C?C coupling reactions between alkenes and nitriles, using PhSiH3 and catalytic Fe(acac)3, are described. This introduces a new strategic bond disconnection for ring-closing reactions, f
- Turner, Oliver J.,Murphy, John A.,Hirst, David J.,Talbot, Eric P. A.
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supporting information
p. 18658 - 18662
(2018/11/23)
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- Tetrahydroindacenyl Catalyst Composition, Catalyst System, and Processes for Use Thereof
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This invention relates to a compound represented by the formula: TyCp′mMGnXq wherein: Cp′ is a tetrahydroindacenyl group which may be substituted or unsubstituted, provided that when Cp′ is tetrahydro-s-indecenyl: 1) the 3 and/or 4 positions are not aryl or substituted aryl, 2) the 3 position is not directly bonded to a group 15 or 16 heteroatom, 3) there are no additional rings fused to the tetrahydroindacenyl ligand, 4) T is not bonded to the 2-position, and 5) the 5, 6, or 7-position is geminally disubstituted; M is a group 3, 4, 5, or 6 transition metal; G is a heteroatom group represented by the formula JRiz where J is N, P, O or S, Ri is a C1 to C20 hydrocarbyl group, and z is 1 or 2; T is a bridging group; y is 0 or 1; X is a leaving group; m=1; n=1, 2 or 3; q=1, 2 or 3, and the sum of m+n+q is equal to the oxidation state of the transition metal.
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Paragraph 0350; 0351; 0352
(2016/09/26)
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- Chiral imidate-ferrocenylphosphanes: Synthesis and application as P,N-ligands in iridium(i)-catalyzed hydrogenation of unfunctionalized and poorly functionalized olefins
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A small library of chiral imidate-ferrocenylphosphane ligands was efficiently synthesized (8 examples) and evaluated in the iridium(i)-catalyzed hydrogenation of unfunctionalized and poorly functionalized olefins. These catalysts perform very well in a range of examples (yields and ee's up to 100%).
- Bert, Katrien,No?l, Timothy,Kimpe, Wim,Goeman, Jan L.,Van Der Eycken, Johan
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supporting information
p. 8539 - 8550
(2013/01/15)
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- Synthesis of five- and six-membered benzocyclic ketones through intramolecular alkene hydroacylation catalyzed by Nickel(0)/N-Heterocyclic Carbenes
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Getting some closure: Mechanistic studies supported the participation of an oxanickelacycle complex in the hydroacylation step of the title reaction, which proceeds without decarbonylation even in the absence of well-known chelation assistance by heteroatoms. Copyright
- Hoshimoto, Yoichi,Hayashi, Yukari,Suzuki, Haruka,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 10812 - 10815
(2013/01/15)
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- N-heterocyclic carbene dichotomy in Pd-catalyzed acylation of aryl chlorides via C-H bond functionalization
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The first Pd-catalyzed intramolecular acylation of aryl chlorides via C-H bond functionalization is presented. The method allows for the synthesis of a variety of elusive benzocyclobutenones with a wide range of functional groups and substitution patterns. We demonstrate that a change in the ligand backbone dictates the selectivity pattern.
- Flores-Gaspar, Areli,Gutierrez-Bonet, Alvaro,Martin, Ruben
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supporting information
p. 5234 - 5237,4
(2012/12/12)
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- N-heterocyclic carbene dichotomy in Pd-catalyzed acylation of aryl chlorides via C-H bond functionalization
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The first Pd-catalyzed intramolecular acylation of aryl chlorides via C-H bond functionalization is presented. The method allows for the synthesis of a variety of elusive benzocyclobutenones with a wide range of functional groups and substitution patterns. We demonstrate that a change in the ligand backbone dictates the selectivity pattern.
- Flores-Gaspar, Areli,Gutierrez-Bonet, Alvaro,Martin, Ruben
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supporting information
p. 5234 - 5237
(2013/01/15)
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- Intramolecular palladium-catalyzed alkane C-H arylation from aryl chlorides
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The first examples of efficient and general palladium-catalyzed intramolecular C(sp3)-H arylation of (hetero)aryl chlorides, giving rise to a variety of valuable cyclobutarenes, indanes, indolines, dihydrobenzofurans, and indanones, are described. The use of aryl and heteroaryl chlorides significantly improves the scope of C(sp3)-H arylation by facilitating the preparation of reaction substrates. Careful optimization studies have shown that the palladium ligand and the base/solvent combination are crucial to obtaining the desired class of product in high yields. Overall, three sets of reaction conditions employing PtBu3, PCyp3, or PCy3 as the palladium ligand and K 2CO3/DMF or Cs2CO3/pivalic acid/mesitylene as the base/solvent combination allowed five different classes of products to be accessed using this methodology. In total, more than 40 examples of C-H arylation have been performed successfully. When several types of C(sp3)-H bond were present in the substrate, the arylation was found to occur regioselectively at primary C-H bonds vs secondary or tertiary positions. In addition, in the presence of several primary C-H bonds, selectivity trends correlate with the size of the palladacyclic intermediate, with five-membered rings being favored over six- and seven-membered rings. Regio- and diastereoselectivity issues were studied computationally in the prototypal case of indane formation. DFT(B3PW91) calculations demonstrated that C-H activation is the rate-determining step and that the creation of a C-H agostic interaction, increasing the acidity of a geminal C-H bond, is a critical factor for the regiochemistry control.
- Rousseaux, Sophie,Davi, Michael,Sofack-Kreutzer, Julien,Pierre, Cathleen,Kefalidis, Christos E.,Clot, Eric,Fagnou, Keith,Baudoin, Olivier
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supporting information; experimental part
p. 10706 - 10716
(2010/09/17)
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- SUBSTITUTED AZOLIN-2-YL-AMINO COMPOUNDS
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The present invention relates to azolin-2-yl-amino compounds of formulae (I. a) and (l.b) and their salts which are useful for combating animal pest, in particular arthropod and nematodes. The present invention also relates to a method for combating such
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Page/Page column 124
(2008/06/13)
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- RECEPTOR FUNCTION REGULATING AGENT
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An agent for regulating 14273 receptor function, which is useful as a preventing or treating drug for diabetes mellitus, hyperlipidemia or the like, is provided. An agent for regulating 14273 receptor function comprising a compound containing an aromatic ring and a group capable of releasing a cation.
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Page/Page column 80
(2010/11/23)
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- RECEPTOR FUNCTION CONTROLLING AGENT
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The GPR40 receptor function regulator of the present invention, which comprises a compound having an aromatic ring and a group capable of releasing cation is useful as an insulin secretagogue or an agent for the prophylaxis or treatment of diabetes and the like.
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Page/Page column 82
(2008/06/13)
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- Asymmetric hydrogenation of tert-alkyl ketones
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A combined system of RuCl2(tolbinap)(pica) and an alkaline or organic phosphazene base catalyzes asymmetric hydrogenation of sterically congested tert-alkyl ketones (TolBINAP = 2,2-bis(di-4-tolylphosphino)-1,1-binaphthyl, PICA = α-picolylamine). Hydrogenation with RuH(η1-BH4)(tolbinap)(pica) does not require any strong base. Alcoholic solvents strongly affect the catalytic efficiency. The reaction proceeds smoothly in ethanol under 1-20 atm of H2 and at room temperature with a substrate to catalyst molar ratio of up to 100000. Various aliphatic, aromatic, heteroaromatic, and olefinic tert-alkyl ketones are convertible to the corresponding chiral carbinols in high enantiomeric purity. Olefinic and heteroaromatic functions are left intact. Certain cyclic ketones are also usable. The mode of enantioface selection is consistent and predictable. Copyright
- Ohkuma, Takeshi,Sandoval, Christian A.,Srinivasan, Rajagopal,Lin, Quinghong,Wei, Yinmao,Muniz, Kilian,Noyori, Ryoji
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p. 8288 - 8289
(2007/10/03)
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- The photochemistry of indenyl alcohols and esters: Substituent effects on the competition between ion- and radical-derived products
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The photochemistry of the indenyl acetates 1 and pivalates 2, substituted with X = H, 5-CH3O, and 6-CH3O, have been examined in both methanol and cyclohexane. The precursor alcohols 3 were also found to be photoreactive. Although only radical-derived products were obtained in cyclohexane, both ion- and radical-derived products were formed in methanol. The absence of significant fluorescence emission from any of the substrates 1, 2, and 3 indicates that the excited singlet states are highly reactive. A mechanism is proposed for the ion-derived products that proceeds through direct heterolytic cleavage to give an indenyl cation - carboxylate anion pair. The indenyl cations generated are anti-aromatic in the ground state and their efficient generation by this photochemical solvolysis is in sharp contrast to the very low reactivity of related ground-state substrates. For the pivalate esters 2, an excited-state migratory decarboxylation is proposed for the formation of tert-butyl derived products.
- Pincock,Young
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p. 1083 - 1095
(2007/10/03)
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- Carbopalladation of nitriles: Synthesis of benzocyclic ketones and cyclopentenones via Pd-catalyzed cyclization of ω-(2-iodoaryl)alkanenitriles and related compounds
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An efficient procedure for the synthesis of 2,2-disubstituted benzocyclic ketones by intramolecular carbopalladation of nitriles has been developed. The cyclization of substituted 3-(2-iodoaryl)-propanenitriles affords indanones in high yields. The reaction is compatible with a wide variety of functional groups. This methodology has been extended to the synthesis of tetralones and cyclopentenones.
- Pletnev, Alexandre A.,Larock, Richard C.
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p. 9428 - 9438
(2007/10/03)
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- Synthesis of benzocyclic ketones via palladium-catalyzed cyclization of ω-(2-iodoaryl)alkanenitriles
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An efficient procedure for the synthesis of 2,2-disubstituted benzocyclic ketones by intramolecular carbopalladation of nitriles has been developed. The cyclization of substituted 3-(2-iodoaryl)propanenitriles affords indanones in high yields. The reactio
- Pletnev, Alexandre A.,Larock, Richard C.
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p. 2133 - 2136
(2007/10/03)
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- A New Redundant Rearrangement of Aromatic Ring Fused Cyclic α-Hydroxydithiane Derivatives. Synthesis of Aromatic Ring Fused Cyclic 1,2-Diketones with One-Carbon Ring Expansion
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A new reaction involving rearrangement of aromatic ring fused cyclic dithiane alcohol by N-chlorosuccinimide in CH2Cl2-H2O to the corresponding one-carbon ring expanded 1,2-diketone has been developed. A wide range of structurally varied dithiane alcohols have been found to undergo this rearrangement in high yields. The general criteria and reaction mechanism for this rearrangement have also been worked out.
- Ranu, Brindaban C.,Jana, Umasish
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p. 6380 - 6386
(2007/10/03)
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- Intramolecular [2 + 2] photocycloaddition of 2-allylindane-1-thiones
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The photochemical reactions of indane-1-thiones 4 were examined. Irradiation of indane-1-thiones 4c-d bearing δ-hydrogen atoms in the side chain gave cyclic thiol derivatives 5c-d via δ-hydrogen atom abstraction by the excited thiocarbonyl sulfur. Irradiation of 2-allylindane-1-thiones 4e-h afforded the multifused thietanes 7e-h by intramolecular [2 + 2] cycloaddition between C=S and C=C bonds. VCH Verlagsgesellschaft mbH, 1996.
- Nishio, Takehiko,Okuda, Norikazu,Kashima, Choji
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p. 117 - 120
(2007/10/03)
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- The Photochemistry of Conformationally Rigid Benzylic Esters: 2,2-Dimethyl-1-indanyl Acetates and Pivalates
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The photochemistry, in methanol, of substituted 2,2-dimethyl-1-indanyl acetates 9a-c and pivalates 10a-c has been studied.In agreement with previous studies on benzylic esters, the results show that the substituents change the yield of products derived from the ion pair.The mechanistic conclusion reached is that the substituents change the oxidation potential of the indanyl radicals and thus the rate constant of electron transfer for converting the radical pair to the ion pair.The results also reveal two other substituent effects.First, substituents can increase the overall efficiency of the photoreaction by enhancing homolytic cleavage.The second effect is conformational.In compounds where the bond that is cleaving is conformationally mobile, such as the C-O bond in benzylic esters, substituents on the ring can change the population of the reactive conformer and thus the overall efficiency of the reaction.For the indanyl acetate esters, the difference in excited-state reaction rate between the m- and p-methoxy substituted ester is 15:1.For the m- and p-methoxy substituted benzyl acetates, this difference in reaction rate is 48:1.The larger difference in reaction rate for the conformationally mobile benzylic esters is attributed to a higher population of the unreactive conformer for the p-methoxy substituted ester.
- Pincock, J. A.,Wedge, P. J.
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p. 4067 - 4076
(2007/10/02)
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- The Endocyclic Restriction Test: An Investigation of the Geometries of Thiophilic Additions of Aryl Radicals and Aryllithium Reagents to Dithioesteres
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Prospective thiophilic additions of aryl radicals and aryllithium reagents in four-, six-, eight-, and 15-membered endocyclic rings have been investigated for the radical and organolithium intermediates generated from the dithioesteres 8-11.These reaction
- Beak, Peter,Park, Yong Sun,Reif, Lee A.,Liu, Chao
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p. 7410 - 7413
(2007/10/02)
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- Rates and Mechanism for the Solvolyses of 2,2-Dimethyl-2-sila-1-indanyl Bromide and α-Trialkylsilylbenzyl p-Toluenesulfonates. α-Silicon Effect on the Stability of Benzylic Cations in Solution
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α-Silicon effect on the benzylic solvolysis has been investigated.The solvolysis of 2,2-dimethyl-2-sila-1-indanyl bromide in aq acetone exhibits a linear response to the solvent ionizing power YBr, with a slope m close to unity (m = 0.93) and g
- Shimizu, Nobujiro,Osajima, Erika,Tsuno, Yuho
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p. 1145 - 1152
(2007/10/02)
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- W(CO)6-Mediated Desulfurdimerization of Dithioketals. Evidence for a Thione Intermediate
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Upon treatment with W(CO)6, dithioketals undergo desulfurdimerization to give the corresponding dimeric olefins in good to excellent yields.The mechanism of this the newly discovered reaction has been investigated.Thioketones have been isolated from the reactions of highly crowded dithioketals.The mechanism for the formation of thioketones has been shown to occur via a new type of radical fragmentation process of dithiolane.Thermolysis of 2,2-dimethylindan-1-yl 2-thiophenoxyethyl sulfide in the presence of tert-butyl adamantane-1-peroxycarboxylate (a typical radical initiator) has been studied for comparison.Thioketones react with W(CO)6, giving dimeric olefins and/or undergoing carbene-like insertion reactions.
- Yeung, Lam Lung,Yip, Yu Chi,Luh, Tien-Yau
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p. 1874 - 1881
(2007/10/02)
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- REDUCTION ELECTROCHIMIQUE DES DERIVES CARBONYLES INSATURES IX. INDANONES ET TETRALONES: ELECTROLYSES MIXTES EN PRESENCE D'ELECTROPHILES
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It is shown that activated cyclic carbonyl compounds, such as tetralones and indanones, can behave in a particular manner when they are reduced in presence of electrophiles.Two classes of electrophiles were chosen: alkyl halides and carbon dioxide.The reactivity (alkylation and carboxylation) often depends on the nature of the activated ketone used as a substrate.
- Moing, Armelle Orliac-Le,Delaunay, Jacques,Lebouc, Alain,Simonet, Jacques
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p. 4483 - 4494
(2007/10/02)
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- Reductive Coupling Reactions of Ketones of the Type of 1-Indanone, 1-Tetralone, and 9-Fluorenone; Conformational Effects in the Series of Indanylidenindanes and Tetralinylidenetetralins
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The ketones 1-indanone (6a) and its derivatives 6b,c and e are coupled by low-valent titanium salts (TiCl4/Zn in THF) to form the corresponding olefins (1a/2a 92:8, 1b/2b 88:12, 1c,e).Reductive coupling of 1-tetralone (12a) yields the olefins 3a and 4a (ca 7:3); from 12b only 3b is isolated.The analogous coupling of the fluorenones 13 can also be achieved with 13b, which is not substituted at C-1 and C-8. - The preferred conformations of olefins 1-5 are dicussed using force-field calculations (Allinger's MMPI); as a result of torsion and out-of-plane deformations of the central double bond these systems are found to be chiral.According to the 1H-NMR spectra olefins 2b and 3b have a stable configuration, in all other cases fast racemization is observed at room temperature.For olefins 3a,b and 12c a "twist-boat" structure is calculated as the only stable form among the possible conformations.The influence of methyl and tert-butyl groups at C-1 and C-8 on the geometries of fluorenylidenefluorenes 5c,d and e is investigated.
- Lemmen, Peter,Lenoir, Dieter
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p. 2300 - 2313
(2007/10/02)
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- 3aH-Indenes. Part 2. Cycloaddition Reactions of 3-Methoxy- and 3-Trimethylsiloxy-3a-methyl-3aH-indene
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The title 3a-methyl-3aH-indenes (1a) and (1b) have been prepared from indan-1-one via the dienone (5) and the trienone (6), and the preparation of the key intermediates (5) and (6) has been improved.The 3aH-indene (1b) behaves similarly to the methoxy derivative (1a), and rearranges on heating to the 1H-isomer.Cycloaddition reactions of (1a) to N-phenylmaleimide and maleic anhydride give isolable -adducts (12), which rearrange on heating to give the exo- and endo--adducts (13) and (14).In contrast, both 2-chloroacrylonitrile and 2-chloroacryloyl chloride give - adducts with (1a).The 2-chloroacryloyl chloride adducts are readily converted into the tricyclic ketone (23).The trimethylsiloxy 3aH-indene (1b) undergoes cycloaddition reactions with dimethyl acetylenedicarboxylate, 2-chloroacryloyl chloride, and dichloroketene.The trimethylsilyl derivative (1b) offers some advantages over the methoxyindene (1a) in synthetic work.
- McCague, Raymond,Moody, Christopher J.,Rees, Charles W.
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p. 2399 - 2407
(2007/10/02)
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- Indaneacetic acid derivatives
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This invention provides new compounds of formula I, STR1 wherein R1 is lower alkyl, R2 is hydrogen or lower alkyl, R3 is hydrogen or lower alkyl, R4 is hydrogen or lower alkyl, R5 is hydrogen, chlorine or lower alkyl, and each of R6 and R7 is hydrogen, or, when R5 is hydrogen, R6 may also be chlorine or lower alkyl, and R7 chlorine or lower alkyl, Useful as anti-phlogistic and anti-arthritic agents.
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