- Effect of Temperature on Borane Reduction of Representative Malonic Acids
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The controlled reaction of phenylmalonic acid (1a) with borane-THF at appropriate temperature makes available (phenylmalonyldioxy)borane , which has been characterized.Reduction of 2a or of the corresponding acid 1a proceeds at 0 deg C at the same rate.The reaction, however, is incomplete, showing only 33percent product formed in 4 h.Diethylmalonic acid (1b), which possesses no α-hydrogen, and the (diethylmalonyldioxy)borane (2b) are reduced at the same rate to the corresponding cyclic dialkoxyborane 5b.These results suggest that the reduction proceeds through intermediate formation of 2.The rates of the borane reduction for a series of malonic acids (1a-h) have been systematically studied and compared at 0 deg C and at -20 deg C.The reductions of aromatic substituted malonic acids (1f-h) are quite sluggish with substantial (46-72percent) α-metalation occurring at 0 deg C.Aliphatic alkylmalonic acids (1d-e) are reduced in 24 h with 34-40percent of α-metalation.At -20 deg C, most malonic acids are completely reduced in times ranging from 24 h for aliphatic (1c-e) to 3 days for aromatic (1f-h) compounds, with only 2-24percent α-metalation.The reduction of 1b at either 0 deg C or -20 deg C is completed in 8 h.At an appropriate lower temperature the reduction successfully competes with the α-metalation.
- Choi, Yong M.,Emblidge, Robert W.,Kucharczyk, Norbert,Sofia, R. Duane
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Read Online
- Synthesis of 14C-felbamate
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14C-Felbamate, 2-[ring-U-14C]phenyl-1,3-propanediol-dicarbamate, (1), was synthesized. The carbon label was introduced into Felbamate using uniformly labelled diethyl 2-phenylmalonate as the starting material.
- Magatti,Lauzon,Saluja,Wang
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- Novel highly potent and selective sigma1 receptor antagonists effectively block the binge eating episode in female rats
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In this paper, the benzo-cracking approach was applied to the potent sigma1 (σ1) receptor antagonist 1 to afford the less conformationally constrained 1,3-dioxane derivatives 2 and 3. To evaluate the effect of the increase in the distance between the two hydrophobic structural elements that flank the basic function, the cis and trans diastereomers of 4 and 5 were also prepared and studied. Compounds 2 and 3 showed affinity values at the σ1 receptor significantly higher than that of the lead compound 1. In particular, 3 displayed unprecedented selectivity over the σ2 receptor, the phencyclidine site of the NMDA receptor, and opioid receptor subtypes, as well as over the dopamine transporter. Docking results supported the structure-activity relationship studies. Due to its interesting biological profile, derivative 3, selected for an in vivo study in a validated preclinical model of binge eating, was able to counteract the overeating of palatable food only in binging rats, without affecting palatable food intake in the control group and anxiety-like and depression-related behaviors in female rats. This result strengthened the involvement of the σ1 receptor in the compulsive-like eating behavior and supported the σ1 receptor as a promising target for the management of eating disorders.
- Del Bello, Fabio,Quaglia, Wilma,Cifani, Carlo,Di Bonaventura, Emanuela Micioni,Botticelli, Luca,Giorgioni, Gianfabio,Pavletic, Pegi,Piergentili, Alessandro,Bonifazi, Alessandro,Schepmann, Dirk,Vistoli, Giulio,Di Bonaventura, Maria Vittoria Micioni
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- Double-Stranded Helical Oligomers Covalently Bridged by Rotary Cyclic Boronate Esters
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Novel double helices covalently bridged by cyclic boronate esters were synthesized from complementary dimers with an m-terphenyl backbone joined by a chiral or achiral phenylene linker bearing diethyl boronates and diols, respectively. The X-ray crystallographic analysis and variable-temperature NMR and circular dichroism measurements, along with theoretical calculations, revealed that the double helices function as a “molecular rotor” in which the cyclic boronate ester units rotate, yielding two stable rotamers at low temperatures. Moreover, our data indicates that the covalently bonded double helices can undergo a unique helix-inversion simultaneously with a rotational motion of the boronate esters.
- Iida, Hiroki,Ohmura, Kenji,Noda, Ryuta,Iwahana, Soichiro,Katagiri, Hiroshi,Ousaka, Naoki,Hayashi, Taku,Hijikata, Yuh,Irle, Stephan,Yashima, Eiji
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Read Online
- Arylsilylation of Electron-Deficient Alkenes via Cooperative Photoredox and Nickel Catalysis
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Carbosilylation of alkenes can be an efficient approach to the synthesis of organosilicon compounds. However, few general methods of carbosilylation are known. Here, we introduce a strategy for arylsilylation of electron-deficient terminal alkenes by combining photoredox-catalyzed silyl radical generation, innate reactivity of silyl radical with alkene, and Ni-catalyzed aryl-Alkyl cross-coupling. This cooperative photoredox and nickel catalysis operates under mild conditions. It employs readily available alkenes, aryl bromides, and silane as reagents, and it produces useful synthetic building blocks in a modular manner.
- Zhang, Zhikun,Hu, Xile
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Read Online
- Synthetic method for non-urethane intermediate 2-phenyl-1,3-propylene glycol
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The invention discloses a synthetic method for a non-urethane intermediate 2-phenyl-1,3-propylene glycol. The synthetic method is characterized in that the 2-phenyl-1,3-propylene glycol can be obtained through the reaction of 2-phenyl-malonate and a reducing agent; and a reaction process includes the following steps: 1) uniformly mixing the 2-phenyl-malonate, the reducing agent and a solvent S1 under a protection gas, controlling a reaction temperature to rise to 130-150 DEG C and pressure to rise to 2-4 atmospheric pressure, dropping an aqueous solution A, controlling the dropping time of theaqueous solution A to be 30-60 min, starting to drop an aqueous solution B when the dropping time of the aqueous solution A arrives 5-8 min, controlling the dropping time of the aqueous solution B tobe 10-12 min, adding a solvent S2 after the adding of the aqueous solution A is finished, controlling the adding time of the solvent S2 to be 5-10 min, then controlling the reaction temperature to be150-160 DEG C and reaction pressure to be 4-6 atmospheric pressure, and finishing cooling after continuously reacting for 2-4 h; and 2) performing filtering and layering after the cooling of a system, and concentrating, steaming and removing the solvents to obtain a product after an organic layer is washed by water and dried by a drying agent. The method is low in raw material price, less in stepand high in yield.
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Paragraph 0023-0052
(2019/10/01)
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- Method for highly efficiently synthesizing 2-phenyl-1,3-propylene glycol
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The invention discloses a method for highly efficiently synthesizing 2-phenyl-1,3-propylene glycol. The method includes the following steps that firstly a silicate active agent is prepared; secondly,ethyl benzoacetate, methyl formate and diisopropyl carbodiimide are used as raw materials for condensation reaction; alpha-formyl ethyl phenylacetate is prepared; then sodium borohydride is used as ahydrogenation reductant, the prepared silicate active agent promotes a reduction reaction, and alpha-formyl ethyl phenylacetate is reduced to prepare 2-phenyl-1,3-propylene glycol. The 2-phenyl-1,3-propylene glycol prepared by the method is high in purity, high in yield, short in reaction time and low in cost.
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Paragraph 0021-0026; 0027-0032; 0033-0038; 0039-0050
(2018/04/21)
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- Structurally Simple Benzylidene-Type Photolabile Diol Protecting Groups
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Two structurally simple photolabile protecting groups for releasing 1,2- and 1,3-diols have been developed. The diols can be protected in high yields and released from their corresponding acetals with high chemical efficiency.
- Ding, Xiong,Devalankar, Dattatray A.,Wang, Pengfei
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supporting information
p. 5396 - 5399
(2016/11/06)
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- Controlling the Conformational Energy of a Phenyl Group by Tuning the Strength of a Nonclassical CH···O Hydrogen Bond: The Case of 5-Phenyl-1,3-dioxane
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Anancomeric 5-phenyl-1,3-dioxanes provide a unique opportunity to study factors that control conformation. Whereas one might expect an axial phenyl group at C(5) of 1,3-dioxane to adopt a conformation similar to that in axial phenylcyclohexane, a series of studies including X-ray crystallography, NOE measurements, and DFT calculations demonstrate that the phenyl prefers to lie over the dioxane ring in order to position an ortho-hydrogen to participate in a stabilizing, nonclassical CH···O hydrogen bond with a ring oxygen of the dioxane. Acid-catalyzed equilibration of a series of anancomeric 2-tert-butyl-5-aryl-1,3-dioxane isomers demonstrates that remote substituents on the phenyl ring affect the conformational energy of a 5-aryl-1,3-dioxane: electron-withdrawing substituents decrease the conformational energy of the aryl group, while electron-donating substituents increase the conformational energy of the group. This effect is correlated in a very linear way to Hammett substituent parameters. In short, the strength of the CH···O hydrogen bond may be tuned in a predictable way in response to the electron-withdrawing or electron-donating ability of substituents positioned remotely on the aryl ring. This effect may be profound: a 3,5-bis-CF3 phenyl group at C(5) in 1,3-dioxane displays a pronounced preference for the axial orientation. The results are relevant to broader conformational issues involving heterocyclic systems bearing aryl substituents.
- Bailey, William F.,Lambert, Kyle M.,Stempel, Zachary D.,Wiberg, Kenneth B.,Mercado, Brandon Q.
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p. 12116 - 12127
(2016/12/23)
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- Synthesis of oxacyclic scaffolds via dual ruthenium hydride/Bronsted acid-catalyzed isomerization/cyclization of allylic ethers
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A ruthenium hydride/Bronsted acid-catalyzed tandem sequence is reported for the synthesis of 1,3,4,9-tetrahydropyrano[3,4-b]indoles (THPIs) and related oxacyclic scaffolds. The process was designed on the premise that readily available allylic ethers would undergo sequential isomerization, first to enol ethers (Ru catalysis), then to oxocarbenium ions (Bronsted acid catalysis) amenable to endo cyclization with tethered nucleophiles. This methodology provides not only an attractive alternative to the traditional oxa-Pictet-Spengler reaction for the synthesis of THPIs, but also convenient access to THPI congeners and other important oxacycles such as acetals.
- Ascic, Erhad,Ohm, Ragnhild G.,Petersen, Rico,Hansen, Mette R.,Hansen, Casper L.,Madsen, Daniel,Tanner, David,Nielsen, Thomas E.
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supporting information
p. 3297 - 3300
(2014/04/03)
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- Facile deprotection of dithioacetals by using a novel 1,4-benzoquinone/cat. NaI system
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The combination of 1,4-benzoquinone and a catalytic amount of NaI was found to be effective for the deprotection of dithioacetals. The reactions proceeded efficiently under mild, near-neutral reaction conditions, producing a wide range of aryl and alkyl aldehydes and ketones generally in high yields with good functional group compatibility. The method developed therefore represents a general, facile, and highly applicable approach for deprotecting dithioacetals.
- Inamoto, Kiyofumi,Yamada, Tetsuya,Kato, Sei-Ichi,Kikkawa, Shoko,Kondo, Yoshinori
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p. 9192 - 9199
(2013/10/01)
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- Synthesis of 3-substituted tetrahydrofuran and 4-substituted tetrahydropyran derivatives by cyclization of dicarboxylic acids with InBr 3/TMDS
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An efficient reduction followed by cyclization of diacid compounds with the InBr3/TMDS system is reported. This system allows the formation of five- and six-membered ring ethers substituted in the 3- or 4-position. Copyright
- Pehlivan, Leyla,Metay, Estelle,Delbrayelle, Dominique,Mignani, Gerard,Lemaire, Marc
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supporting information; experimental part
p. 4689 - 4693
(2012/09/22)
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- PROCESS FOR THE PREPARATION OF 2-PHENYL-1,3-PROPANEDIOL
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The present invention is related to a novel synthetic procedure that provides a simple, safe and commercially valuable method for the preparation of 2-phenyl-1,3-propanediol. The process for the preparation of 2-phenyl-1,3-propanediol involves reducing diethyl phenylmalonate with sodium borohydride (NaBH4) in the presence of an alkali metal dihydrogen phosphate buffer or the hydrate thereof.
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Page/Page column 6
(2012/03/27)
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- Carbon-carbon bond cleavage in fluorescent pyronin analogues induced by yellow light
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A novel class of pyronin analogues, which undergoes a photochemically induced cleavage of the C-C bond in the presence of water in both solution and on a silica gel surface upon direct irradiation with visible light, is reported. The reaction course can be monitored by characteristic fluorescence of both the starting compound and the final product. This system could find useful applications in the field of photoremovable protecting groups or caged fluorophores.
- ?tacko, Peter,?ebej, Peter,Veetil, Aneesh Tazhe,Klán, Petr
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supporting information
p. 4918 - 4921
(2013/01/15)
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- Aerobic lactonization of diols by biomimetic oxidation
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Coming up for air: Highly efficient aerobic lactonization can be carried out by a biomimetic oxidation system based on coupled redox catalysts (ruthenium catalyst and electron transfer mediators). This system leads to a low-energy electron transfer from diol to molecular oxygen. Various diols were aerobically oxidized to the corresponding five- to nine-membered lactones in good to high yields under mild reaction conditions (see scheme).
- Endo, Yoshinori,Baeckvall, Jan-E.
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supporting information; experimental part
p. 12596 - 12601
(2011/12/03)
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- Photolabile protection of 1,2- and 1,3-diols with salicylaldehyde derivatives
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(Chemical Equation Presented) 1,2- and 1,3-diols, including carbohydrates, can be readily caged as acetals of 5-methoxy- or 5-hydroxysalicylaldehydes. Irradiation of these acetals with 300 nm light results in their efficient (Φ = 0.2-0.3) cleavage, regenerating an aldehyde and a glycol in excellent chemical yield. Photoreactive 5-hydroxysalicylaldehyde acetals can be produced by mild in situ reduction of photostable p-quinone precursors.
- Kostikov, Alexey P.,Popik, Vladimir V.
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scheme or table
p. 5277 - 5280
(2009/06/18)
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- Facile reduction of malonate derivatives using NaBH4/Br2: an efficient route to 1,3-diols
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Borane-dimethoxyethane generated from sodium borohydride-bromine mixtures efficiently reduces a wide range of malonate derivatives to the corresponding 1,3-diols. This new reagent system represents a milder alternative to current methods available, providing the requisite 1,3-diols in higher yields over shorter reaction times.
- Tudge, Matthew,Mashima, Hiroko,Savarin, Cecile,Humphrey, Guy,Davies, Ian
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p. 1041 - 1044
(2008/09/17)
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- Site-specific and asymmetric hydrolysis of prochiral 2-phenyl-1,3- propanediol diacetate by a bacterial esterase from an isolated strain
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Bacillus cereus 809A and Burkholderia sp. 711C were isolated from soil. These strains demonstrate hydrolysis activity towards prochiral 2-phenyl-1,3-propanediol diacetate and accumulated the corresponding chiral monoacetates into the reaction mixture. When 2-phenyl 1,3-propanediol diacetate was used as a substrate, the produced monoacetates with Burkholderia sp. 711C were obtained in a racemic form but that produced by Bacillus cereus 809A showed an excess of the (S)-form. The resting cell reaction revealed that for Bacillus cereus 809A, there was an enrichment of one of the enantiomers of the monoacetate such that the enantiomeric excess (e.e.) of the (S)-form was over 95%. The purified enzyme from Bacillus cereus 809A hydrolyzed diacetate to monoacetate, and the e.e. value of the (S)-form increased by prolonged reaction in a way similar to the resting cell reaction. From N-terminal amino acids, this esterase is conserved in some strains of Bacillus for which the genomic sequences have been reported.
- Mitsui, Ryoji,Shinya, Seiho,Ichiyama, Yuichi,Kudo, Kenta,Tsuno, Takuo,Tanaka, Mitsuo
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p. 1858 - 1864
(2008/02/13)
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- CHOLESTERYL ESTER TRANSFER PROTEIN INHIBITORS
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Compounds of Formula (I), including pharmaceutically acceptable salts of the compounds, are CETP inhibitors, and are useful for raising HDL-cholesterol, reducing LDL-cholesterol, and for treating or preventing atherosclerosis. In the compounds of Formula (I), A1 is a cyclic group, and B is a cyclic group which is attached to the heterocyclic ring directly or through a methylene group.
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Page/Page column 27
(2008/06/13)
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- Methods for synthesis of dicarbamate compounds and intermediates in the formation thereof
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Disclosed is a method of making 2-substituted-2-halo-1,3-propanediols via reduction of corresponding malonate compounds. Also disclosed is a method of making 2-substituted-2-halo-1,3-dicarbamate compounds (such as halo derivatives of felbamate, including fluorofelbamate) via reduction of malonate compounds, followed by carbamoylation. Reduction of the malonate compounds is carried out using an electrophilic hydride reagent.
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Page/Page column 7-8
(2008/06/13)
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- Zirconium borohydride piperazine complex, an efficient, air and thermally stable reducing agent
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A zirconium borohydride piperazine complex (Ppyz)Zr(BH4) 2Cl2, obtained by the reaction of an ethereal solution of ZrCl4 and LiBH4 with piperazine is a stable, selective and efficient reducing agent. (Ppyz)Zr(BH4)2Cl 2 reduces aldehydes, ketones, silylethers, α, β-unsaturated carbonyl compounds and esters. The reactions were performed in diethyl ether at room temperature or under reflux, and the yields of the corresponding alcohols were excellent. The selective reduction of aldehydes in the presence of ketones and complete regioselectivity in the reduction of α,β-unsaturated carbonyl groups were observed.
- Tajbakhsh,Lakouraj,Shirini,Habibzadeh,Nikdoost
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p. 3295 - 3299
(2007/10/03)
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- An efficient method for the cleavage of p-methoxybenzylidene (PMP), tetrahydropyranyl (THP) and 1,3-dithiane protecting groups by Selectfluor
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A new and efficient method for the cleavage of the PMP, THP and 1,3-dithiane protecting groups with Selectfluor has been developed.
- Liu, Junjie,Wong, Chi-Huey
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p. 4037 - 4039
(2007/10/03)
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- Ferrocenyl derivatives with one, two, or three sulfur-containing arms for self-assembled monolayer formation
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Self-assembled monolayers of electroactive molecules can form on gold electrodes if the molecules include a sulfur-containing group to coordinate with the gold surface. We have prepared a molecule with a tripod of sulfur groups that has the potential of fixing the geometry of the molecule relative to the gold surface. The target (3) contained the good one-electron donor ferrocene connected through a benzene spacer to an isobutane tripod, with each arm of the tripod ending in a methylthio group. Analogous compounds with one (1) and two (2) coordinating arms were also prepared.
- Hu, Jian,Mattern, Daniell Lewis
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p. 2277 - 2281
(2007/10/03)
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- Acyclic phenylalkanediols as substrates for the study of enzyme recognition: Synthesis of substrates and enzymatic resolution via hydrolysis and transesterification
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Different racemic or prochiral phenyl alkane (1,n)-diols were synthesized, and their resolution was carried out by two different strategies: enzymatic transesterification with vinyl acetate, or enzymatic hydrolysis of their corresponding diacetates, in both cases catalysed by porcine pancreatic lipase (PPL). The absolute configuration of the optically enriched reaction products was determined by formation of Mosher's esters or by the use of the Benzene Sector and Benzene Chirality Rules as obtained from the Circular Dichroism spectra.
- Rumbero, Angel,Borreguero, Isabel,Sinisterra, Jose V.,Alcantara, Andres R.
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p. 14947 - 14960
(2007/10/03)
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- Lipase-based HPLC stationary phase: Enantioselective synthesis of 2- substituted 1,3-propanediol monoacetates
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Pseudomonas cepacia lipase (PCL) has been immobilized by coating the enzyme on an epoxysilica HPLC column. The biocatalyst has been successfully used for the preparation of both the enantiomers of 3-acetoxy-2-benzyl- propan-1-ol and of 3-acetoxy-2-methylpropan-1-ol. The immobilized enzyme is active after months of use either in aqueous or in organic media. (C) 1999 Elsevier Science Ltd.
- Bertucci, Carlo,Petri, Antonella,Felix, Guy,Perini, Benedetta,Salvadori, Piero
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p. 4455 - 4462
(2007/10/03)
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- Diastereoselective synthesis of ω-phosphonic acid analogues of 4-arylkainoids
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Radical cyclisation by the use of α,β-unsaturated phosphonate as a radical acceptor was applied to a synthesis of 7-phosphonomethylpyrrolo[1,2-c]oxazolidinones, synthetic intermediates on the route to phosphonic acid analogues of kainoids. The relative configuration at the 6;7;7a-positions was found to be highly controlled by steric effects due to the substituent at the 6-position. Thus, diethyl [{(6S*,7R*,7aS*)-6-(2-methoxyphenyl)-3-oxoperhydropyrrolo[1,2- c]-[1,3]oxazol-7-yl}methyl]phosphonate 29a and diethyl [{(6S*,7R*,7aS*)-3-oxo-6-phenylperhydropyrrolo[1,2-c][1,3]- oxazol-7-yl}methyl]phosphonate 29b were prepared with high diastereoselectivity. When the substituent at the 6-position is a 1-naphthyl group, the diethyl [{(6S*,7R*,7aS*)-6-(1-naphthyl)pyrroloxazol-7-yl}methyl] phosphonate 29c and its (6S*,7R*,7aR*)-isomer 30c were formed in the ratio 29c:30c～2:1. The stereostructure of compound 29a was determined by X-ray crystallographic analysis. The 6-o-methoxyphenyl derivative 29a was converted into the corresponding phosphonic acid analogue 33.
- Yuasa, Yoko,Fujimaki, Nobuko,Yokomatsu, Tsutomu,Ando, Jun,Shibuya, Shiroshi
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p. 3577 - 3584
(2007/10/03)
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- 24-and 25-substituted avermectin and milbemycin derivatives
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Novel avermectin and milbemycin derivatives are disclosed, where the C-24 and C-25 carbon atoms are substituted by hydrogen, alkyl, alkenyl, substituted alkyl or substituted alkenyl groups. These compounds can be further substituted at the 4"-, 5-, 13-, and 23-positions. The new C-24 and C-25 substituted avermect prepared by cleavage of known and suitably protected avermectin and milbemycin compounds. The new compounds are potent anti-parasitic agents, in particular, the compounds are anthelmintic, insecticidal and acaricidal agents.
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- Influence of a 2-fluoro substituent on diastereoselectivity in the 1,3-dipolar cycloadditions of nitrones
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It is clear that the role of 1,2-asymmetric induction on the 1,3-dipolar cycloaddition of nitrones is influenced by the presence of a fluorine atom at the C-2 position. 2-Fluoro nitrones, synthesized by three different methods, have been subjected to the intermolecular 1,3-dipolar cycloaddition with ethyl vinyl ether. The stereostructures of isoxazolidines formed were determined by their conversion into 2,7-dioxa-6-azabicyclo[3.2.1]octanes. The diastereoselectivity of 2-fluoro nitrones was the reverse of that of the corresponding 2-hydro nitrones. This fact supports that the conformation with relief from the dipole repulsion between the fluorine atom and the oxygen atom of the nitrone is a preferred one for 2-fluoro nitrones, while the corresponding 2-hydro nitrones adopt the conformation with the least 1,3-allylic strain.
- Ihara, Masataka,Tanaka, Yuko,Takahashi, Nobuyuki,Tokunaga, Yuji,Fukumoto, Keiichiro
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p. 3043 - 3052
(2007/10/03)
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- Synthesis of tetrahydroquinolines, hexahydrobenzoindolizines and an aryl phosphonate linker for the generation of catalytic antibodies
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Syntheses of 6-methoxy-1-methyl-1,2,3,4-tetrahydroquinoline-3-methanol 10 and 1,2,3,5,6,10b-hexahydrobenzo[g]indolizine-6-methanol 34 are described. The aryl phosphonic acid 14, which can be used as a linker to a protein, is synthesised and coupled to the above alcohols. These haptens, when linked to a protein, are intended to generate antibodies able to catalyse cationic cyclisation reactions.
- Gonzalez-Bello, Concepcion,Abell, Chris,Leeper, Finian J.
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p. 1017 - 1024
(2007/10/03)
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- Hydrogen-bonded complexes of oxetanes and other ethers with nitric acid and with trifluoroacetic acid in trichloromethane
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Equilibrium constants for hydrogen-bonded complexation of nitric acid and trifluoroacetic acid with 3,3-pentamethylneoxetane, oxetane, 3-phenyloxetane, tetrahydrofuran, butyl methyl ether, 3-(4-nitrophenyl)oxetane and dibenzyl ether, measured by 1H NMR spectroscopy, are reported.Reasons for the signal broadening observed with the more strongly basic ethers with nitric acid but not with trifluoroacetic acid are discussed.
- Hylands, Kevin A.,Moodie, Roy B.
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p. 2073 - 2078
(2007/10/03)
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- 2-alkoxy- or acyloxy-2-aryl-1,3-propanediol or dioxane derivative, and process for its production
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A compound that can be converted, at a low cost and in a simple way, into 2-aryl-1,3-propanediols serving as precursors for synthesizing felbamate acting as an antiepileptic has a structure represented by Formula (1): STR1 wherein Ar represents an aryl group; R1 represents a hydrogen atom or is R4 or R5, where R4 represents an alkoxy group having 1 to 10 carbon atoms and R5 represents a hydroxy group or an acyloxy group having 1 to 10 carbon atoms; and R2 and R3 are hydrogen atoms at the same time or R2 and R3 together form a group represented by Formula (2): STR2 wherein R6 and R7 each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, or R6 and R7 together form an oligomethylene group having 2 to 10 carbon atoms.
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- A Chemoenzymatic Synthesis of Both Enantiomers of 2-Phenyl-3-hydroxypropylcarbamate, a Metabolite of Felbamate
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PPL catalyzed desymmetrization of 2-phenyl-1,3-propanediol (3) was the key step in the chemoenzymatic synthesis of both enantiomers of 2-phenyl-3-hydroxypropylcarbamate (2).Unsuccessful attempts at enzyme catalyzed (PPL, Novo SP435) transcarbamoylation, aminolysis and ammonolysis are also described.
- Morgan, Brian,Bydlinsky, Greg,Dodds, David R.
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p. 1765 - 1772
(2007/10/02)
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- On the optimization of pig pancreatic lipase catalyzed monoacetylation of prochiral diols
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The effect of various experimental variables (solvent, methodology of supportation on celite, presence of water, conversion and so on) on the rate and on the enantioselectivity of monoacetylation of some prochiral 2-substituted-1,3-propanediols with vinyl acetate catalyzed by crude PPL (pig pancreatic lipase) was analyzed. This study allowed to assess the best conditions for performing these transformations, providing an efficient methodology for the synthesis of valuable chiral building blocks with moderate amounts of inexpensive PPL, which can also be easily recycled.
- Banfi,Guanti,Riva
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p. 1345 - 1356
(2007/10/02)
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- Electron transfer in P450 mechanisms. Microsomal metabolism of cyclopropylbenzene and p-cyclopropylanisole
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The metabolism of cyclopropylbenzene (1a) and 4-cyclopropylanisole (1b) was studied using liver microsomal preparations from control, phenobarbital- and β-naphthoflavone treated rats. With all three types of microsomes 1a was metabolized by benzylic hydroxylation to give 1-phenylcyclopropanol and by aromatic hydroxylation at C-4; the former predominated by a factor of 2-4. BNF-induced microsomes also formed 2-cyclopropylphenol. No cyclopropyl ring-opened metabolites of 1a, including benzoic acid, were detected in any of the incubations. With PB-induced microsomes 1b underwent O-demethylation (90%) and benzylic hydroxylation; no other metabolites were detected. Progress curves for metabolism of 1a are markedly nonlinear after only limited conversion of substrate, suggesting the possibility that 1a, like other cyclopropyl compounds, could be a suicide substrate for one or more isozymes of P450. For both 1a and b, metabolite formation and enzyme inactivation can be explained by conventional P450 reaction mechanisms not involving electron abstraction.
- Riley,Hanzlik
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- Unique Template Effects of Distannoxane Catalysts in Transesterification of Diol esters
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1,n-Diol diacetates (n = 2,3,4) are selectively converted into the corresponding monoacetates by distannoxane-catalyzed transesterification.Such unique selectivity is not encountered with 1,n-diol diacetates where n>/=5.A great difference in reactivity is also seen in the transesterification between methyl butyrate and 1,n-diol monoacetates: the ethylene glycol derivative sluggishly undergoes transesterification whereas higher homologs react smoothly.The unique template effects of the catalysts are discussed in terms of cooperation of two different tin atoms which are located in the proximity.
- Otera, Junzo,Dan-oh, Nobuhisa,Nozaki, Hitosi
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p. 3065 - 3074
(2007/10/02)
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- Process for the preparation of 2-aryl-1,3-propanediols
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Process for the production of 2-aryl-1,3-propanediols and novel intermediate compounds produced thereby.
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- Process for the preparation of 2-aryl-1,3-propanediols
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Process for the production of 2-aryl-1,3-propanediols from a tropate ester and novel intermediate compounds produced thereby.
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- Reduction of diethyl phenylmalonate to 2-phenyl-1,3-propanediol
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Syntheses for the preparation of 2-phenyl-1,3-propanediol, a useful intermediate for the preparation of 2-phenyl-1,3-propanediol dicarbamate, by the selective reduction of diethyl phenylmalonate with the Lewis acid type metal hydrides diisobutylaluminum hydride (DIBAH) or borane dimethylsulfide (BMS) in solution with heterocyclic ethers are disclosed.
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- Conversion of diethyl phenylmalonate to 2-phenyl-1,3-propanediol
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Synthesis of 2-phenyl-1,3-propanediol by the selective reduction of diethyl phenylmalonate with metal hydrides in solution with heterocyclic ethers are disclosed.
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- Enzyme catalyzed monohydrolysis of 2-aryl-1 3-propanediol diacetates. A study of structural effects of the aryl moiety on the enantioselectivity
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PPL catalyzed monohydrolysis of 2-aryl substituted 13-propanediol diacetates afforded the corresponding monoacetates in acceptable to fair chemical and optical yields. Electronic effects in the aromatic ring were examined. Elaboration of some 2-arylpropanediol monoacetates to optically active 2-arylpropanols and propanoic acids was performed.
- Guanti, Giuseppe,Narisano, Enrica,Podgorski, Tadeusz,Thea, Sergio,Williams, Andrew
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p. 7081 - 7092
(2007/10/02)
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- Synthesis of 2-phenyl-1,3-propanediol
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A novel method for preparing 2-phenyl-1, 3-propanediol and its dicarbamate is disclosed which readily lends itself to commercial production.
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- SYNTHESIS OF BOTH ENANTIOMERIC FORMS OF 2-SUBSTITUTED 1,3-PROPANEDIOL MONOACETATES STARTING FROM A COMMON PROCHIRAL PRECURSOR, USING ENZYMATIC TRANSFORMATIONS IN AQUEOUS AND IN ORGANIC MEDIA
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A direct entry to both enantiomeric forms c and ent-c based on enzyme catalyzed transformations of prochiral compounds of type a and b is described.The catalysts used are carboxyl esterase preparations obtained from crude porcine pancreas lipase.
- Tombo, G. M. Ramos,Schaer, H.-P.,Busquets Fernandez I,Ghisalba, O.
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p. 5707 - 5710
(2007/10/02)
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- 2-Oxo-1,3,2-dioxathianes. I. Preparation of the Alkyl-substituted Derivatives
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2-Oxo-1,3,2-dioxathiane, all methyl- and several other alkyl-substituted 2-oxo-1,3,2-dioxathianes have been synthesized by condensing 1,3-alkanediols and thionyl chloride.The amount of the S==O-axial and S==O-equatorial isomers can be controlled by adding pyridine to the reaction mixture.
- Virtanen, Terttu,Nikander, Hannu
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p. 113 - 116
(2007/10/02)
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- Enantiotopically Selective Oxidation of α,ω-Diols with the Enzyme Systems of Microorganisms
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Gluconobacter were found to be capable of oxidizing prochiral diols such as 2-substituted propane-1,3-diols 1 and 3-substituted pentane-1,5-diols 4 with distinction of pro-R and pro-S sites of the molecules, in that (-)-(R)-α-substituted β-hydroxypropionic acids 2 and (+)-(3S)-3-substituted δ-valerolactones 5 were obtained, respectively.Oxidation of 3-methylpentane-1,3,5-triol 11 afforded unnatural (+)-(S)-mevalonolactone 12.The steric bulkiness of the substituents on the prochiral center and the distance from the hydroxy group greatly affected the rate and the enantioselectivity of the reaction.
- Ohta, Hiromichi,Tetsukawa, Hatsuki,Noto, Naoko
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p. 2400 - 2404
(2007/10/02)
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