Showing 1-30 of 34 results for "

t76201

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Shigeyuki Yamada et al.
Organic & biomolecular chemistry, 9(15), 5493-5502 (2011-06-16)
2,2,3,3-Tetrafluorooxetane reacted easily with organolithium reagents to give 1,1,3-trisubstituted 2,2-difluoropropan-1-ols in good to excellent yields. On the other hand, the reaction with Grignard reagent led to 3-bromo-1,1-disubstituted 2,2-difluoropropan-1-ols in good yields. On treating with lithium enolates, generated from enol silyl...
Waldemar Kulig et al.
The journal of physical chemistry. A, 115(23), 6149-6154 (2011-02-09)
Clathrate hydrates with polar guest molecules (dimethyl ether, ethylene oxide, trimethylene oxide, tetrahydrofuran, and tetrahydropyran) were studied by means of the density functional theory. A model of a large cage of structure-I clathrate was employed. Optimal configurations of encaged guests...
Exploiting the lithiation-directing ability of oxetane for the regioselective preparation of functionalized 2-aryloxetane scaffolds under mild conditions.
Donato Ivan Coppi et al.
Angewandte Chemie (International ed. in English), 51(30), 7532-7536 (2012-06-15)
Xiu-Ling Liu et al.
Chemistry (Weinheim an der Bergstrasse, Germany), 19(39), 13216-13223 (2013-08-14)
The photochemical reaction of a pyrimidine and a ketone occurs either as a Paternò-Büchi (PB) reaction or as energy transfer (ET) from the triplet ketone to the pyrimidine. It is rare for the two types of reactions to occur concurrently...
Antonia F Stepan et al.
Journal of medicinal chemistry, 54(22), 7772-7783 (2011-10-15)
A metabolism-based approach toward the optimization of a series of N-arylsulfonamide-based γ-secretase inhibitors is reported. The lead cyclohexyl analogue 6 suffered from extensive oxidation on the cycloalkyl motif by cytochrome P450 3A4, translating into poor human liver microsomal stability. Knowledge...
Radical addition of ethers to alkenes under dioxygen catalyzed by N-hydroxyphthalimide (NHPI)/Co(OAc)2.
Hirano K, et al.
Tetrahedron Letters, 43(20), 3617-3620 (2002)
Santosh Keshipeddy et al.
The Journal of organic chemistry, 77(18), 7883-7890 (2012-08-24)
Laureatin, a metabolite of the red algae Laurencia nipponica, has shown potent activity as a mosquito larvicide. The two previously published syntheses of laureatin involved an initial preparation of the 8-membered cyclic ether, followed by formation of the oxetane ring....
Photocatalytic Synthesis of Oxetane Derivatives by Selective C-H Activation.
Ravelli D, et al.
Advanced Synthesis & Catalysis, 356(13), 2781-2786 (2014)
Radical ?-C? H Hydroxyalkylation of Ethers and Acetal.
Yoshimitsu T, et al.
The Journal of Organic Chemistry, 70(6), 2342-2345 (2005)
Feng Gao et al.
Chemical & pharmaceutical bulletin, 60(3), 415-418 (2012-03-03)
A selective intramolecular transacylation from C-4 to C-5 of taxoids, which occurred simultaneously with the oxetane D-ring opening and was promoted by TiCl4, was presented. The optimal condition was found to be treatment of substrates in double dose of dichloromethane...
Cascade formation of isoxazoles: facile base-mediated rearrangement of substituted oxetanes.
Johannes A Burkhard et al.
Angewandte Chemie (International ed. in English), 50(23), 5379-5382 (2011-05-04)
Ken Hisamoto et al.
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology, 10(9), 1469-1473 (2011-05-05)
The Paternò-Büchi (PB) reaction of geraniol derivatives 1, which contain allylic alcohol functionality and unfunctionalized double bonds, with benzophenone was investigated to see the effect of the hydroxyl group on the regioselectivity of the oxetane formation, i.e., 2/3. At low...
Dong-Dong Wu et al.
Organic & biomolecular chemistry, 10(18), 3626-3635 (2012-04-13)
Photoinduced reactions of isatin and N-methyl-1,3,4-isoquinolinetrione with bicycloalkylidenes such as bicyclopropylidene, cyclopropylidenecyclobutane, cyclopropylidenecyclohexane and bicyclohexylidene were investigated. The reactions gave spirooxetanes as the major products derived from the [2 + 2] photocycloaddition pathway via 1,4-biradical recombination. Unusual products including the...
Role of polar side chains in Li+ coordination and transport properties of polyoxetane-based polymer electrolytes.
Sai R, et al.
Physical Chemistry Chemical Physics, 19(7), 5185-5194 (2017)
Johannes A Burkhard et al.
Angewandte Chemie (International ed. in English), 49(48), 9052-9067 (2010-10-30)
Sizable resources, both financial and human, are invested each year in the development of new pharmaceutical agents. However, despite improved techniques, the new compounds often encounter difficulties in satisfying and overcoming the numerous physicochemical and many pharmacological constraints and hurdles....
Youhei Yabuno et al.
Journal of the American Chemical Society, 133(8), 2592-2604 (2011-02-11)
A set of photochemical oxetane formation reactions, i.e., the Paternò-Büchi (PB) reactions, of tetrahydrobenzofuranol derivatives 1a-d with benzophenone (BP) was investigated to examine poorly understood hydroxy-group directivity on regio- and stereoselectivity. The selectivities of the PB reactions for allylic alcohols...
Sarah F Jenkinson et al.
Chimia, 65(1-2), 71-75 (2011-04-08)
Alpha-Triflates of gamma-lactones with potassium carbonate in methanol give efficient contraction of the ring to oxetane-1-carboxylates in which the oxygen substituent at C(3) of the oxetane is predominantly trans to the carboxylate at C(2), regardless of the stereochemistry of the...
Oxetanes: recent advances in synthesis, reactivity, and medicinal chemistry.
Bull JA, et al.
Chemical Reviews, 116(19), 12150-12233 (2016)
Zhao bo Yang et al.
The journal of physical chemistry. B, 115(31), 9681-9686 (2011-06-21)
The mechanism of formation of azetidine and oxetane in (6-4) photoproducts between thymine and imine-type cytosine is studied using the MPWB1K and B3LYP functionals together with the 6-31G(d,p) and 6-311++G(d,p) basis sets, in vacuum and bulk solvent. The photoinduced cycloaddition...
Diana Thaens et al.
Chemical research in toxicology, 25(10), 2092-2102 (2012-08-15)
Organic electrophiles have the potential to covalently attack DNA bases, and thus initiate mutagenic and carcinogenic processes. In this context, aromatic nitrogen sites of the DNA bases are often particularly nucleophilic, with guanine N7 being one of the most favored...
Synthesis and characterization of high molecular weight poly (trimethylene oxide).
Qureshi MY and Ochel M
Eur. Polymer J., 32(6), 691-693 (1996)
Cross-linked poly (oxetane) matrix for polymer electrolyte containing lithium ions.
Tsutsumi H, et al.
Solid State Ionics, 262, 761-764 (2014)
Ming Cheng et al.
Chemistry & biodiversity, 7(8), 2035-2039 (2010-08-24)
A new taxoid metabolite was isolated from the MeOH extract of Taxus cuspidata needles. The structure was established as (2alpha,5alpha,7beta,9alpha,10beta,13alpha)-10,13,20-tris(acetyloxy)-1,4,5,7,9-pentahydroxytax-11-en-2-yl benzoate on the basis of spectral analyses including 1H- and 13C-NMR, HMQC, HMBC, and NOESY, and confirmed by HR-FAB-MS.
Johannes A Burkhard et al.
Organic letters, 14(1), 66-69 (2011-11-25)
The preparation of versatile azaspiro[3.3]heptanes carrying multiple exit vectors is disclosed. Expedient synthetic routes enable the straightforward access to these novel modules that are expected to have significance in drug discovery and design.
Philipp Selig et al.
Chemical communications (Cambridge, England), 49(28), 2930-2932 (2013-03-06)
The first synthesis of highly substituted 3-alkyl-oxetan-2-ylidenes from allenoates was developed by using the bicyclic guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as an exceptionally active nitrogen Lewis base catalyst.
Macrocyclization of oxetane building blocks with diazocarbonyl derivatives under rhodium(II) catalysis.
Diane Rix et al.
Angewandte Chemie (International ed. in English), 50(32), 7308-7311 (2011-07-02)
Luciana Capece et al.
The journal of physical chemistry. B, 116(4), 1401-1413 (2011-12-27)
Indoleamine 2,3-dioxygenase (IDO) and tryptophan dioxygenase (TDO) are two heme proteins that catalyze the oxidation reaction of tryptophan (Trp) to N-formylkynurenine (NFK). Human IDO (hIDO) has recently been recognized as a potent anticancer drug target, a fact that triggered intense...
Three-component assembly and divergent ring-expansion cascades of functionalized 2-iminooxetanes.
Weijun Yao et al.
Angewandte Chemie (International ed. in English), 49(48), 9210-9214 (2010-10-22)
Johannes A Burkhard et al.
Organic letters, 15(17), 4312-4315 (2013-08-14)
Oxetanes are used in drug discovery to enable physicochemical and metabolic property enhancement for the structures to which they are grafted. An imide C═O to oxetane swap on thalidomide and lenalidomide templates provides analogs with similar physicochemical and in vitro...
Donato Ivan Coppi et al.
Chemical communications (Cambridge, England), 47(35), 9918-9920 (2011-08-05)
A valuable and direct method to access 2-substituted-2-phenyloxetanes by electrophilic quenching of the corresponding 2-lithiated derivative has, for the first time, been described. 2-Lithiated-2-phenyloxetane was found to be configurationally unstable. Evidence is presented to show that electron-transfer processes are also...