- Acyl iodides in organic synthesis. Reaction of acetyl iodide with Dialkyl sulfides and disulfides
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Reactions of acetyl iodide with dialkyl and dialkenyl sulfides RSR (R = Et, Bu, CH2=CH, CH2=CHCH2) and with disulfides RSSR (R = Pr, C6H13, PhCH2) were studied. Dialkyl sulfides reacted with MeCOI to give the corresponding alkyl ethanethioates and alkyl iodides as a result of cleavage of the S-C bond. The reactions of acetyl iodide with divinyl and diallyl sulfides involved addition across the double bond and subsequent polymerization of 1-alkenylsulfanyl-2(3)- iodoalkyl methyl ketones. Dialkyl disulfides RSSR (R = Pr, C6H 13) and dibenzyl disulfide reacted with acetyl iodide via cleavage of the S-S bond to produce the corresponding ethanethioates and organylsulfenyl iodides. The latter underwent disproportionation to form the initial disulfide and molecular iodine.
- Vlasova,Grigor'Eva,Voronkov
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- Silver triflate catalyzed acetylation of alcohols, thiols, phenols, and amines
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A variety of alcohols, thiols, phenols, and amines were subjected to acetylation reaction using acetic anhydride in the presence of catalytic quantity of silver triflate. The method described has a wide range of applications, proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time. Georg Thieme Verlag Stuttgart · New York.
- Das, Rima,Chakraborty, Debashis
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experimental part
p. 1621 - 1625
(2011/06/25)
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- Facile catalyzed acylation of alcohols, phenols, amines and thiols based on ZrOCl2·8H2O and acetyl chloride in solution and in solvent-free conditions
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Acylation of heteroatoms (O, N and S) with acetyl chloride based on the use of a catalytic amount of the moisture stable, inexpensive ZrOCl 2?8H2O, proceeds efficiently producing the corresponding acylated products in excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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p. 147 - 151
(2007/10/03)
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- Facile catalyzed acylation of heteroatoms using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride
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Acylation of a variety of alcohols, phenols, aliphatic and aromatic amines, a thiol and a thiophenol proceeds efficiently using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride in a solvent or under solventless conditions, furnishing the corresponding acylated derivatives in very good to excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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p. 6775 - 6778
(2007/10/03)
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- Transacylation of α-Aryl-β-keto Esters
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The acyl group of an α-aryl-β-keto ester was readily transferred to N-, O-, and S-nucleophiles. The transacylation from arylated diethyl 3-oxoglutarate to amines led to unsymmetrical malonic acid amide esters in high yields. The present reaction proceeded under mild conditions without formation of detectable byproducts. Only simple experimental manipulations were required. This reaction was also found to be sensitive to steric factors, which enabled the chemoselective monoacylation of diamines and amino alcohols without any modifications such as protection.
- Nishiwaki, Nagatoshi,Nishida, Daisei,Ohnishi, Tetsuya,Hidaka, Fumie,Shimizu, Satoru,Tamura, Mina,Hori, Kazushige,Tohda, Yasuo,Ariga, Masahiro
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p. 8650 - 8656
(2007/10/03)
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- Mutation of cysteine-295 to alanine in secondary alcohol dehydrogenase from thermoanaerobacter ethanolicus affects the enantioselectivity and substrate specificity of ketone reductions
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The mutation of Cys-295 to alanine in Thermoanaerobacter ethanolicus secondary alcohol dehycrogenase (SADH) was performed to give C295A SADH, on the basis of molecular modeling studies utilizing the X-ray crystal structure coordinates of the highly homologous T. brockii secondary alcohol dehydrogenase (YKF.PDB). This mutant SADH has activity for 2-propanol comparable to wild-type SADH. However, the C295A mutation was found to cause a significant shift of enantioselectivity toward the (S)-configuration in the reduction of some ethynylketones to the corresponding chiral propargyl alcohols. This result confirms our prediction that Cys-295 is part of a small alkyl group binding pocket whose size determines the binding orientation of ketone substrates, and, hence, the stereochemical configuration of the product alcohol. Furthermore, C295A SADH has much higher actifity towards t-butyl and some α-branched ketones than does wild-type SADH. The C295A mutation does not affect the thioester reductase activity of SADH. The broader substrate specificity and altered stereoselectivity for C295A SADH make it a potentially useful tool for asymmetric reductions. Copyright
- Heiss, Christian,Laivenieks, Maris,Zeikus,Phillips, Robert S.
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p. 1659 - 1666
(2007/10/03)
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- Electrochemical carbon dioxide fixation to thioesters catalyzed by [Mo2Fe6S8(SEt)9]3-
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A controlled potential electrolysis at -1.55 V versus SCE of CO2-saturated CH3CN containing (Et4N)3[Mo2Fe6S 8(SEt)9], CH3C(O)SEt, Bu4NBF4, and Molecular Sieve 3A as a desiccant produced CH3C(O)COO- with a current efficiency of 27%. Similar electrolysis using C2H5C(O)SEt and C6H5C(O)SEt also catalytically afforded C2H5C(O)COO- and C6H5C(O)COO- with current efficiencies of 49 and 13%, respectively. These reactions are strongly inhibited by the presence of not only H2O but also excess EtS-. Strong acylating agents such as acetyl chloride, acetic anhydride, acetyl sulfide, and acetylimidazole in place of CH3C(O)SEt caused decomposition of [Mo2Fe6S8(SEt)9]3-, and no CH3C(O)COO- was formed under the same electrolysis conditions.
- Komeda, Nobutoshi,Nagao, Hirotaka,Matsui, Tatsuji,Adachi, Gin-Ya,Tanaka, Koji
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p. 3625 - 3630
(2007/10/02)
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- A Formylcarbonium Ion Synthon. Synthesis of 3-Thio-Substituted 2-Amino Acids and Thio-Substituted Enamines from 2-Acyloxyacrylonitriles
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The utilization of 2-acyloxy-3-phenylthiopropionitriles (2) which were prepared by the Michael addition of thiophenol to 2-acyloxyacrylonitriles (CH2=C(CN)OCOR), as a formylcarbonium ion synthon, was demonstrated by the transformation of 2 into S-phenylcysteine and 2-phenylthio enamines.
- Oku, Akira,Hori-ie, Naofumi,Harada, Toshiro
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p. 609 - 612
(2007/10/02)
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- HOMOLYTIC TRANSFORMATIONS OF 1,3-OXATHIOLANES AT HIGH PRESSURE
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The effect of high pressure was studied on the rate and direction of the homolytic transformations of 1,3-oxathiolanes.Pressure reduces the rate of the transformation of 2-methyl- and 2-isopropyl-1,3-oxathiolanes to ethyl and 2-chloroethyl thoiacylates in the presence of CCl4 to a greater extent than the initiation rate in the system.The selectivity of the formation of the reaction product which is formed more rapidly at normal pressure is increased in the competing homolytic transformations of 2-methyl- and 2-isopropyl-1,3-oxathiolanes to the corresponding ethyl thioacylates with increasing pressure.The yield of the cyclic adduct, 2-methyl-2-hexyl-1,3-oxathiolane, relative to that of linear octyl thioacetate is increased in the homolytic addition of 2-methyl-1,3-oxathiolane to 1-hexane with increasing pressure.
- Trifonova, V. N.,Zorin, V. V.,Batyrbaev, N. A.,Makarova, Z. G.,Zlotskii, S. S.,et al.
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p. 1386 - 1389
(2007/10/02)
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- AN EXCEPTIONALLY MILD, PHASE TRANSFER CATALYZED METHOD FOR THE CONVERSION OF THIOCARBONYL COMPOUNDS TO CARBONYLS
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The thiocarbonyl group of thioketones, dithioesters, thioamides, and thioureas can be converted to the carbonyl function by treatment with sodium hydroxide under phase transfer conditions.
- Alper, Howard,Kwiatkowska, Caroline,Petrignani, Jean-Francois,Sibtain, Fazle
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p. 5449 - 5450
(2007/10/02)
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- DIASTEREOFACIAL SELECTIVITY VIA ALDOL REACTIONS USING ETHYL DITHIOACETATE AND ETHYL DITHIOPROPIONATE ENOLATES
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The lithium enolate of ethyl dithioacetate reacts with α-methyl aldehydes to yield the aldol products in which the syn configuration in the positions β and γ to the thiocarbonyl of the product is favored over the anti configuration.This selectivity is solvent-dependent, and is enhanced at lower temperatures.In most cases, syn:anti product ratios obtained under these conditions varied from 57:43 to >99:1, depending upon the structure of the α-methyl aldehyde.When the lithium enolate of ethyl dithiopropionate was allowed to react with α-methyl aldehydes, only two out of the four possible diastereomers were detected in the product mixtures.
- Meyers, A. I.,Walkup, Robert D.
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p. 5089 - 5106
(2007/10/02)
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- ACTIVITY OF 1-OXA-3-THIACYCLOALKANES AND 2-ALKYLTHIOOXACYCLANES IN FREE-RADICAL ISOMERIZATION
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It was established that radical isomerization to alkyl esters of thiocarboxylic acids, initiated by tert-butyl peroxide at 130-150 deg C, is a common reaction for five-, six- and seven-membered 1-oxa-3-thiacycloalkanes and 2-alkylthiooxacycloalkanes.Under analogous conditions 2-diethylaminotetrahydropyran isomerizes to N,N-diethylvaleramide.The relation between the structure and the reactivity of 1-oxa-3-thiacycloalkanes and 2-alkylthiooxacycloalkanes in free-radical isomerisation was studied by the method of competing reactions.Depending on the ring size, the activity of the 1-oxa-3-thiacycloalkanes increases in the order : 1,3-oxathianes 1,3-oxathiolanes 1,3-oxathiepanes.
- Zorin, V. V.,Batyrbaev, N. A.,Zlot-skii, S. S.,Rakhmankulov, D. L.
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p. 347 - 352
(2007/10/02)
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- Gas-phase Thermolyses. Part 8. Gas-phase Thermolysis of Methyl and Ethyl Monothioacetates
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The unimolecular gas-phase thermolyses of the four methyl and ethyl monothioacetates (5)-(8) have been studied by the flash vacuum thermolysis-field ionization mass spectrometry technique in the temperature range 883-1404 K.The types of reactions verified were keten formation, thiono-thiolo rearrangement, and, in the case of the ethyl esters, ethylene elimination.The possible mechanisms for keten formation are discussed, and it is concluded that the thiono-carboxylates eliminates the mercaptan via an enethiolized structure, whereas the decomposition of the thiolo-esters apparently proceeds via direct 1,2-elimination of the thiols.
- Carlsen, Lars,Egsgaard, Helge
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p. 1081 - 1086
(2007/10/02)
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- Production of S-Methyl Thioacetate from Methyl Mercaptan by Brewer's Yeast
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S-Methyl thioacetate (MeSAc) production by brewer's yeast from methyl mercaptan (MeSH) was investigated under various conditions.At optimum, 98 mg/liter of MeSAc was produced from 500 mg/liter of MeSH contained in culture broth.The MeSAc level in yeast growth medium was increased with increasing MeSH at relatively low levels (10 to 500 mg/liter).However, higher MeSH levels in medium (over 1 g/liter) inhibited yeast growth, and no MeSAc was produced.MeSAc was formed readily by incubating MeSH with yeast resting cells.Furthermore, S-ethyl or S-n-propyl thioacetate accumulated in yeast cell suspension when ethyl or n-propyl mercaptan, respectively, was incubated with resting cells.MeSAc was also produced from L-methionine by brewer's yeast, but its formation was dramatically inhibited by copper ions.This finding suggests that MeSH is an intermediate product between L-methionine and MeSAc.
- Matsui, Shin-ichi,Amaha, Mikio
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p. 1341 - 1350
(2007/10/02)
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- Pesticidal compositions containing phosphoric esters and divalent sulphur compounds
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Pesticidal composition comprising: a pesticidal, phosphoric ester the molecule of which has at least one alkyl group of 1 to 3 carbon atoms, 0.05 to 10% of an agent stabilizing the said ester against decomposition by protonisation, together with adjuvants characterized in that the stabilizing agent comprises at least one sulphur compound containing per molecule at least one divalent sulphur atom of which one valence is bonded to an atom chosen from sulphur, carbon, nitrogen, hydrogen, and metals capable of giving a salt, the other valence being bonded to an atom chosen from hydrogen, the carbon atom already noted, a second carbon atom, the nitrogen atom already noted, a second nitrogen atom, the metal atom already noted in the case of a metal of valence greater than one, a second atom of metal and oxygen when the first valence is not attached to an atom of hydrogen, the proportion of sulphur calculated with reference to the weight of the sulphur compound being between 5 and 99%. Process for stabilizing a phosphoric ester of which the molecule possesses at least one alkyl group containing 1 to 3 carbon atoms characterized in that there is added to the phosphoric ester or to a mixture which contains it, 0.05 to 10% calculated on the weight of the phosphoric acid ester of an agent capable of stabilizing the said phosphoric ester against protonisation and comprising at least one sulphur compound such as that defined thereupon.
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