- Electricity Driven 1,3-Oxohydroxylation of Donor-Acceptor Cyclopropanes: a Mild and Straightforward Access to β-Hydroxy Ketones
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An unprecedented external oxidant-free electrochemical protocol for 1, 3-oxohydroxylation of donor-acceptor cyclopropane is disclosed. The strategy encompasses the activation of the labile π-electron cloud of the aryl ring to cleave the strained Csp3?Csp3 bond of cyclopropane to afford the β-hydroxy ketones via insertion of molecular oxygen. More significantly, based on the detailed mechanistic investigations and cyclic voltammetry experiments, a plausible mechanism is proposed.
- Banerjee, Prabal,Maajid Taily, Irshad,Saha, Debarshi
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supporting information
p. 5053 - 5057
(2021/09/30)
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- Volatiles from the xylarialean fungus Hypoxylon invadens
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The volatiles emitted by agar plate cultures of the xylarialean fungus Hypoxylon invadens were investigated by use of a closed loop stripping apparatus in combination with GC-MS. Several aromatic compounds were found that could only be identified by comparison to all possible constitutional isomers with different ring substitution patterns. For the set of identified compounds a plausible biosynthetic scheme was suggested that gives further support for the assigned structures.
- Dickschat, Jeroen S.,Wang, Tao,Stadler, Marc
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p. 734 - 746
(2018/04/16)
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- Towards the rational design of novel charge-transfer materials: Biaryls with a dihedral angle-independent hole delocalization mechanism
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Biaryl cation radicals are important electroactive materials, which show two mechanisms of hole delocalization: static delocalization at small interplanar dihedral angles and dynamic hopping at larger angles, reflecting the interplay between electronic coupling and structural reorganization. Herein, we describe the rational design of biaryls possessing an invariant hole delocalization mechanism.
- Ivanova, Lena V.,Navale, Tushar S.,Wang, Denan,Lindeman, Sergey,Ivanov, Maxim V.,Rathore, Rajendra
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supporting information
p. 5851 - 5854
(2018/06/13)
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- Synthetic studies on Ecteinascidin-743: synthesis of building blocks through Sharpless asymmetric dihydroxylation and aza-Michael reactions
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A practical and an efficient synthesis of three building blocks of tetrahydroisoquinoline alkaloid Ecteinascidin-743 was accomplished, starting from readily available piperonal, 2-methyl anisole, and veratraldehyde. A combination of Vilsmeier-Haack reaction and Sharpless asymmetric dihydroxylation was employed for the synthesis of building blocks A and B whereas a Heck reaction in PEG-2000 and aza-Michael reactions were employed for the synthesis of building block C.
- Chandrasekhar,Reddy, N. Ramakrishna,Rao, Y. Srinivasa
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p. 12098 - 12107
(2007/10/03)
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- PEROXISOME PROLIFERATOR ACTIVATED RECEPTOR MODULATORS
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The present invention is directed to a compound of formula (I), or a pharmaceutically acceptable salt, solvate hydrate or stereoisomer thereof, which is useful in treating or preventing disorders mediated by a peroxisome proliferator activated receptor (PPAR) such as syndrome X, type II diabetes, hyperglycemia, hyperlipidemia, obesity, coagaulopathy, hypertension, arteriosclerosis, and other disorders related to syndrome X and cardiovascular diseases.
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Page/Page column 102-103
(2010/02/11)
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- An eco-friendly regeneration of aldehydes exploiting ammonium acetate under microwave irradiation
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A number of bisulphite addition products and diacetates are deprotected separately to the corresponding aldehydes exploiting a green reagent, ammonium acetate in solvent-free conditions under microwave irradiation by a rapid, clean, efficient and high yielding method under environmentally benign conditions.
- Mitra, Alok Kumar,Karchaudhuri, Nilay,De, Aparna
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p. 237 - 239
(2007/10/03)
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- Isoquinoline compound melanocortin receptor ligands and methods of using same
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The invention relates to melanocortin receptor ligands and methods of using the ligands to alter or regulate the activity of a melanocortin receptor. The invention further relates to tetrahydroisoquinoline aromatic amines that function as melanocortin receptor ligands and as agents for controlling cytokine-regulated physiologic processes and pathologies, and combinatorial libraries thereof.
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- Iodination of Methylated Anisoles: Unusual Aryl Methyl Replacement and Oxidations
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The treatment of methylated anisoles with iodine, periodic acid, sulfuric acid, and aqueous acetic acid has resulted in iododemethylations and/or aryl methyl oxidations in addition to the expected mono- and diiodinations of the aromatic ring.Four dimethylanisoles and o-methylanisole were treated under identical conditions.Iododemethylations were observed in three of the four dimethylanisoles and aryl methyl oxidations to benzaldehydes occured with o-methylanisole and two of the dimethylanisoles.No precedence could be found for either of these reactions under the experimental conditions employed.Several possible mechanisms are discussed for these transformations.Some experimental evidence suggests that methyl oxidation to a benzaldehyde could be a prerequisite for an iododemethylation via an iodonium ion-assisted reverse Gatterman-Koch reaction; single-electron-transfer or classical electrophilic mechanisms are also consistent with the iododemethylations.
- Panetta, Charles A.,Fang, Zheng,Mattern, Daniell L.
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p. 7953 - 7958
(2007/10/03)
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- Radical-Cation Catalysis in the Synthesis of Diphenylmethanes via the Dealkylative Coupling of Benzylic Ethers
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The dealkylative coupling of benzyl alkyl ethers (ArCH2OR) to yield the corresponding diarylmethanes (ArCH2Ar) together with dialkoxymethane (ROCH2OR) is catalyzed by small amounts of 1-electron oxidants (such as aromatic cation radicals, NO(1+), etc.) or by an equivalent electrochemical (anodic) method.The catalytic method is successfully employed for the facile synthesis of a novel macrocyclic crown ether 18 that contains a diarylmethane linkage.On the basis of the spectral observation of the radical cation ArCH2OR.+ and the excellent catalytic efficiency with turnover numbers in excess of 1E2, an electron-transfer and an alternative electrophilic chain mechanism are discussed for the dealkylative coupling process.
- Rathore, Rajendra,Kochi, Jay K.
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p. 7479 - 7490
(2007/10/03)
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- Diterpenes of Azadirachta indica. Syntheses to confirm structure
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The structure of the diterpene nimbinone 1b has been confirmed by syntheses via a cascade cyclisation and also from podocarpic acid by two separate series of transformations. Synthesis of structure 3b from dehydroabietic acid shows that this does not exhibit the properties described for nimbosodione.
- Burnell,Dumont,Theberge,Desfosses
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p. 2571 - 2578
(2007/10/02)
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- Oxidative Dealkylation of 4-Substituted N,N-Dialkylanilines with Molecular Oxygen in the Presence of Acetic Anhydride Promoted by Cobalt(II) or Copper(I) Chloride
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The reaction of 4-substituted N,N-dimethylanilines 1a-d with acetic anhydride 5 proceeded efficiently in the presence of a catalytic amount of cobalt(II) or copper(I) chloride under oxygen to give the corresponding N-methylacetanilides 2a-d along with N-methylformanilides 3a-d.The reaction of N-alkyl-N-methyl-p-toluidines 1f-h with cobalt chloride revealed that the order of reactivity of the N-substituents follows the sequence allyl > benzyl >/= methyl > ethyl, while in the case of copper chloride the order was benzyl > allyl > methyl > ethyl.Aldehydes 18a-e and phenylglyoxylic acid derivatives 18f and 18g were obtained in fair to good yield from the reaction of n-substituted N-ethyl-p-toluidines 17a-g.
- Murata, Satoru,Suzuki, Kaoru,Tamatani, Akira,Miura, Masahiro,Nomura, Masakatsu
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p. 1387 - 1392
(2007/10/02)
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- Process for nucleophilic fluoroalkylation of aldehydes
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Aryl difluoromethyl sulfone adds to alkehydes under phase transfer conditions to give novel substituted alcohols of the general formula wherein R is an aryl, cycloaliphatic, sec- or tert-aliphatic, or heterocyclic group and Ar is an aryl group. The substituted alcohols of formula I are of particular utility as intermediates in the synthesis of a variety of useful end products. For example, the products of formula I may be utilized in desulfonylation reactions, oxidation reactions and fluorination reactions.
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- Ortho Metalation Directed by α-Amino Alkoxides
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The addition of aromatic aldehydes to certain lithium dialkylamides in benzene or tetrahydrofuran gave α-amino alkoxides which were ortho lithiated with excess n-butyllithium.Subsequent alkylation and hydrolysis provided ortho-substituted aromatic aldehydes via a one-pot reaction.The ortho metalation of α-amino alkoxides derived from 1- and 2-naphthaldehyde and various substituted benzaldehydes was examined.When N,N,N'-trimethylethylenediamine was used as the amine component of the α-amino alkoxide, metalation could be carried out at lower temperatures.This rate increase is due to an intramolecular TMEDA-like assisted metalation.The synthetic utility of this ortho metalation, including how varying the amine component of the α-amino alkoxide affects the regiochemistry and metalation rate, is discussed.
- Comins, Daniel L.,Brown, Jack D.
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p. 1078 - 1083
(2007/10/02)
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- Indirect Electrooxidation (an Ex-Cell Method) of Alkylbenzenes by Recycle Use of (NH4)2Ce(NO3)6 in Various Solvent Systems
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Indirect electrooxidation (an ex-cell method) of the side chain of alkylbenzenes has been performed by recycle use of (NH4)2Ce(NO3)6 (CAN) in various solvent systems.The side-chain oxidation of p-methoxytoluene (1) with CAN in methanol proceeds smoothly, yielding anisaldehyde (3, 94percent), while use of aqueous methanol or acetic acid resulted in a mixture of 3 and the dimeric product 4 (19-35percent) along with complex products (28-47percent).Electrooxidation of the recovered cerium(III) salts was perfomed smoothly in methanol by passing 1.1-1.2 F/mol of electricity to give a reddish methanol solution of CAN, which can be used for the next oxidation of 1.The repeated use of CAN over 10 times produced the desired 3 in over 90percent yields.Similarly, the oxidation of alkylbenzenes, bearing p-methoxy group, gave the corresponding side-chain-oxidized products.In contrast, p-tert-butyltoluene (9e) could be oxidized by heating with CAN in aqueous 50percent acetic acid at 85-90 deg C to give p-tert-butylbenzaldehyde in over 90percent yield.The regeneration of CAN after the oxidation of 9e was also accomplished by electrolysis in the aqueous 50percent acetic acid system.The reaction mechanisms in connection with the nature of CAN in various solvent systems are discussed.
- Torii, Sigeru,Tanaka, Hideo,Inokuchi, Tsutomu,Nakane, Shoji,Akada, Mitsuo,et al.
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p. 1647 - 1652
(2007/10/02)
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