- Thiolation of cycloalkenes C5, C6 by redox-activation of hydrogen sulfide
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Direct and indirect redox-activation of H2S in the presence of cyclopentene or cyclohexene in MeCN at 25?°C affords the corresponding cycloalkanethiols.
- Shinkar, Elena V.,Kudryavtsev, Daniil A.,Pashchenko, Konstantin P.,Berberova, Nadezhda T.,Okhlobystina, Alexandra V.
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p. 180 - 182
(2017/03/30)
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- Melamine-(H2SO4)3/melamine-(HNO3)3 instead of H2SO4/HNO3: A safe system for the fast oxidation of thiols and sulfides under solvent-free conditions
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Melamine reacted with neat sulfuric acid and fuming nitric acid readily to form two new organic solid acids, namely melamine-(H2SO4)3 and melamine-(HNO3)3. Mixture of them acts as a unique powerful system instead of a hazardous H2SO4/HNO3 system for the direct oxidation of thiols. Also, this system can oxidize the sulfides in the presence of a catalytic amount of KBr and few drops of water. This procedure offers advantages such as very low reaction time, simple work-up, excellent yield and matching with some green chemistry protocols.
- Chehardoli, Gholamabbas,Zolfigol, Mohammad Ali
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p. 606 - 612
(2015/11/17)
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- CERTAIN DIPEPTIDYL PEPTIDASE INHIBITORS
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Provided are certain dipeptidyl peptidase inhibitors, pharmaceutical compositions thereof, and methods of use therefor.
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Paragraph 0184
(2014/06/11)
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- CERTAIN DIPEPTIDYL PEPTIDASE INHIBITORS
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Provided are certain dipeptidyl peptidase inhibitors, pharmaceutical compositions thereof, and methods of use therefor.
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Paragraph 0184
(2014/06/11)
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- CERTAIN DIPEPTIDYL PEPTIDASE INHIBITORS
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Provided are certain dipeptidyl peptidase inhibitors, pharmaceutical compositions thereof, and methods of use therefor.
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Page/Page column 43
(2012/07/14)
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- CERTAIN DIPEPTIDYL PEPTIDASE INHIBITORS
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Provided are compounds represented by formula (I), their pharmaceutical compositions, and their uses for preparing medicaments as inhibitors of dipepetidyl peptidase-IV enzyme, wherein each substitutuent of formula (I) is defined as the description.
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Page/Page column 44
(2012/07/14)
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- CERTAIN DIPEPTIDYL PEPTIDASE INHIBITORS
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Provided are certain dipeptidyl peptidase inhibitors, pharmaceutical compositions thereof, and methods of use therefor.
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Page/Page column 43
(2012/07/14)
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- The deoxygenation of sulfoxide mediated by the Ph3P/Lewis acid combination and the application to the kinetic resolution of racemic phosphines using optically active sulfoxide
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It was found that the combination of Ph3P/TiCl4 was an effective promoter for the deoxygenation of sulfoxides and gave the corresponding sulfides in good yield (up to 97%) under mild conditions. This method was applied to the reaction between racemic phosphines and (R)-methyl p-tolyl sulfoxide, and it was found that the kinetic resolution was achieved in moderate selectivities.
- Kikuchi, Satoshi,Konishi, Hiroyuki,Hashimoto, Yukihiko
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p. 3587 - 3591
(2007/10/03)
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- Trifluoroacetylation of unsymmetrical ketone acetals. A convenient route to obtain alkyl side chain trifluoromethylated heterocycles
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A convenient method to obtain β-alkyl-β-methoxyvinyl trifluoromethyl ketones [CF3COCHC(OMe)R, where R = Et, n-Pr, i-Pr, i-Bu, t-Bu, -(CH2)2OMe] from the regiospecific acylation of kinetic enol ether generated in situ is reported. The unsymmetrical ketone dimethyl acetals react with trifluoroacetic anhydride in the presence of pyridine using dry chloroform as solvent with a temperature range of 25-60°C. These acetals [R-C(OMe)2Me] are obtained from the reaction of alkyl methyl ketones with trimethyl orthoformate in the presence of p-toluenesulfonic acid as catalyst in pure methanol as solvent. The new acetylated enol ethers proved to be versatile building blocks for the construction of interesting alkyl trifluoromethyl substituted heterocycles. Thus, examples of isoxazoline, pyrazoline, pyrazole and pyrimidinone have been obtained in good yields (62-79%).
- Bonacorso, Helio G.,Martins, Marcos A.P.,Bittencourt, Sandra R.T.,Lourega, Rogerio V.,Zanatta, Nilo,Flores, Alex F.C.
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p. 177 - 182
(2007/10/03)
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- FUNCTIONALIZATION OF SATURATED HYDROCARBONS IN THE PRESENCE OF APROTIC ORGANIC SUPERACIDS. 2. SINGLE-STAGE SYNTHESIS OF THIOESTERS R1CO-SR FROM n-ALKANES OR CYCLOALKANES (RH), ELEMENTAL SULFUR, AND COMPLEXES R1COBr*2AlBr3
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It has been found for the first time that n-alkanes and cycloalkanes (RH) can interact with elemental sulfur at ca. 20 deg C.These reactions go forward in the presence of aprotic organic superacids with the composition R1CO-SR in satisfactory yields.
- Orlinkov, A. V.,Akhrem, I. S.,Afanas'eva, L. V.,Vitt, S. V.,Vol'pin, M. E.
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- Enantio- and Diastereoselective α-Metallation of Prochiral Sulfoxides by (+)-Menthyllithium
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Six out of ten prochiral dialkyl sulfoxides 3 with diastereotopic α methylene protons were stereoselectively metallated by (+)-menthyllithium (11) to yield two diastereomeric pairs of enriched enantiomers 29 after the reaction with benzophenone.The maximum e.e. was 40percent.Dicyclohexyl sulfoxide (3c) was deprotonated enantioselectively with an e.e of 30percent. 2-Bornyllithium (21) was unsuccesful as a chiral base and was shown for the first time to contain 4percent of isobornyllithium (22).The reactions were performed in pentane at -80 deg C; in diethyl ether and THF the e.e's were only slightly higher, and at higher temperatures the selectivity was rapidly decreasing.It was shown that racemization takes place by an intermolecular transmetallation reaction.The structure of 29f (n = 3) was elucidated by an X-ray analysis.Key Words: (+)-Menthyllithium, stereoselective metallation with/ Prochiral sulfoxides, enantio- and diastereoselective α-deprotonation of / 2-Bornyllithium, content of isobornyllithium in / Racemization, mechanism by intermolecular transmetallation/ e.e., temperature dependence of
- Maercker, Adalbert,Schuhmacher, Rudolf,Buchmeier, Willi,Lutz, Heinz Dieter
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p. 2489 - 2498
(2007/10/02)
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- NEW SYNTHESIS OF 1,2,5-SELENADIAZOLES
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A new synthesis of 1,2,5-selenadiazoles which starts from unsubstituted or monosubstituted 1,2,5-thiadiazoles and Grignard reagents is described and the mechanism of the reaction discussed.
- Bertini, Vincenzo,Munno, Angela De,Picci, Nevio,Lucchesini, Francesco,Pocci, Marco
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p. 2153 - 2158
(2007/10/02)
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- CHEMISTRY OF A MOLYBDENUM-PERSULFIDE COMPLEX: ALKYLATION AND OXIDATIVE COUPLING
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The reaction of alkyl halides, sulfinyl and sulfonyl chlorides with (NH4)2 has been found to afford sulfides and disulfides in good-excellent yield.The effect of solvent polarity and reaction time is discussed.
- Harpp, David N.,MacDonald, J. Gavin
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p. 703 - 706
(2007/10/02)
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- FORMATION OF SULPHUR COMPOUNDS DURING THE HYDRODENITROGENATION OF ANILINE, CYCLOHEXYLAMINE, BENZYLAMINE, AND 2-PHENYLETHYLAMINE ON A NICKEL-TUNGSTEN CATALYST IN THE PRESENCE OF HYDROGEN SULPHIDE
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Hydrodenitrogenations of aniline, cyclohexylamine, benzylamine, and 2-phenylethylamine were performed on a sulphided nickel-tungsten catalyst at 300 deg C in an autoclave filled with hydrogen in the absence and in the presence of hydrogen sulphide.Due to the presence of hydrogen sulphide the degree of conversion increased from 0.9 to 3,6percent for aniline and from 72 to 99percent for benzylamine, and the fraction of neutral substances increased from 2.4 to 7percent for cyclohexylamine and from 5.0 to 8.9percent for 2-phenylethylamine.The neutral fractions contained cyclohexanethiol, thiobenzamide, 2-phenylethanethiol, and other sulphur compounds giving evidence that the increased degree of conversion of the amines was due to the hydrogen sulphide taking direct part in the chemical reaction.
- Cerny, Mirko,Trka, Antonin
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p. 2387 - 2392
(2007/10/02)
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- Chemical Conversions using Sheet Silicates: Novel Intermolecular Eliminations of Hydrogen Sulphide from Thiols
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Aliphatic primary and secondary thiols react in the interlamellar layers of ion-exchanged montmorillonite catalysts to produce dialkyl sulphides via intermolecular elimination of hydrogen sulphide; similar processes result in the production of diphenyl sulphide from benzenethiol and poly(phenylenemethylene) from α-toluenethiol.
- Ballantine, James A.,Galvin, Robert P.,O'Neil, Robert M.,Purnell, Howard,Rayanakorn, Mongkon,Thomas, John M.
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p. 695 - 696
(2007/10/02)
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- REACTION OF SULFUR HALIDES WITH UNSATURATED COMPOUNDS XV. 2,2'-DICHLORO SULFIDES IN REACTION WITH ORGANOALUMINUM COMPOUNDS
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The reaction of 2,2'-dichloro sulfides with organoaluminum compounds was investigated.The reaction leads to dechlorination or alkylation products, depending on the structure of the organoaluminum compounds.It was established that nickel, titanium, and zirconium compounds have catalytic activity and enabled the reactions to occur under milder conditions.The addition of sulfur dichloride to 1-methyl- and 1,5-dimethyl-1,5-cyclooctadienes was investigated, and the rearrangement was followed in the series of 9-thiabicyclononane derivatives.
- Tolstikov, G. A.,Kantyukova, R. G.,Spirikhin, L. V.
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p. 1210 - 1218
(2007/10/02)
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