- A Mild Method for Access to α-Substituted Dithiomalonates through C-Thiocarbonylation of Thioester: Synthesis of Mesoionic Insecticides
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An efficient method for targeting a variety of symmetrical and asymmetrical α-substituted dithiomalonates (DTMs) is described, utilizing 1H-imidazole-1-carbothioates as reactive acylating agents and MgBr2?OEt2/DBU or LiHMDS for soft or hard enolization conditions of thioesters, respectively. The utility of this methodology was demonstrated through the synthesis of the pyridopyrimidine mesoionic insecticides: triflumezopyrim and dicloromezotiaz. (Figure presented.).
- Di, Huiming,Jin, Hui,Ma, Yanrong,Ryu, Do Hyun,Wang, Xiaochen,Yang, Xinyue,Zhang, Lixin
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supporting information
p. 3201 - 3206
(2021/05/31)
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- Acyl transfer from carboxylate, carbonate, and thiocarbonate esters to enzymatic and nonenzymatic thiolates
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Transglutaminases (EC 2.3.2.13) (TGases) catalyze calcium-dependent acyl transfer reactions between peptide-bound glutamine residues as acyl donors and peptide-bound lysine residues as acyl acceptors, resulting in the formation of intermolecular ε-(γ-glutamyl)lysine crosslinks. The mechanistic details of its "ping-pong" transamidation reaction remain unknown. In particular, few studies have been published probing the nucleophilicity of TGase using acyl-donor substrates of varied electrophilicity. Herein we report the synthesis of activated esters of carbonates, carbamates, and thiocarbonates and their reactions with simple thiols, as a nonenzymatic point of reference, and with the catalytic cysteine residue of guinea pig liver TGase. Our kinetic results show that the simple substitution of a side chain methylene unit by oxygen or sulphur had a surprising effect on both substrate affinity and acylation reactivity. Furthermore, they provide unexpected insight into the importance of a side chain heteroatom for conferring affinity for tissue TGase as well as revealing an interesting class of irreversible inhibitors.
- Gravel, Christian,Lapierre, Danielle,Labelle, Judith,Keillor, Jeffrey W.
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p. 164 - 174
(2008/02/13)
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- A simple and direct method for converting thioamides into thioesters
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Thioamides may be transformed into thioesters through the simple expedient of warming them in an aqueous THF solution containing an alkylating agent. Reactions proceed in high yield and are amenable to multi-gram scale.
- Harrowven, David C.,Lucas, Matthew C.,Howes, Peter D.
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p. 1187 - 1196
(2007/10/03)
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- Hydrophobic Vitamin B12. V. Electrochemical Carbon-Skeleton Rearrangement as Catalyzed by Hydrophobic Vitamin B12: Reaction Mechanisms and Migratory Aptitude of Functional Groups
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The carbon-skeleton rearrangements as catalyzed by heptamethyl cobyrinate perchlorate, 1ester>ClO4, were investigated under electrochemical conditions.The controlled-potential electrolysis of 2,2-bis(ethoxycarbonyl)-1-bromopropane, which is considered to be a model substrate for methylmalonyl-CoA mutase, was catalyzed by 1ester>ClO4 in N,N-dimethylformamide to give the rearrangement product, 1,2-bis(ethoxycarbonyl)propane, as a major one at -1.5 V vs.SCE in the presence of acetic acid and at potentials more cathodic than -1.8 V vs.SCE without acetic acid in the dark.The electrochemical carbon-skeleton rearrangement was postulated to proceed via formation of anionic intermediates.The electrolyses of 1-bromo-2-cyano-2-ethoxycarbonylpropane, 2-acetyl-1-bromo-2-ethoxycarbonylpropane, and 1-bromo-2-propane with 1ester>ClO4 also afforded the corresponding carbon-skeleton rearrangement products.The results indicated that substrates with two electron-withdrawing groups placed on the β-carbon atom with combination of one carboxylic ester and one of carboxylic ester, acetyl, and cyano moieties readily gave the corresponding rearrangement products which were derived from individual migration of the substituent groups.Substrates with only one of the electron-withdrawing groups, carboxylic ester, acetyl, and cyano, did not give any rearrangement product, but a substrate with one thioester group afforded the corresponding rearrangement product.The migratory aptitude of electron-withdrawing groups was found to decrease in the order: COSR>COR>COOR>CN.Both electronic character and steric bulkiness of the migrating groups are apparently reflected on this tendency, even though relative contributions of these effects are much dependent on the nature of β-substituents.
- Murakami, Yukito,Hisaeda, Yoshio,Ozaki, Toshiaki,Tashiro, Takako,Ohno, Teruhisa,et al.
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p. 311 - 324
(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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- Synthesis of Thiol Esters by Carboxylic Trichlorobenzoic Anhydrides
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Thiocarboxylic S-esters were obtained rapidly and in high yields by treating the mixed anhydrides prepared from 2,4,6-trichlorobenzoyl chloride and carboxylic acid, with various types of thiols in the presence of 4-dimethylaminopyridine.
- Kawanami, Yasuhiro,Dainobu, Yuichiro,Inanaga, Junji,Katsuki, Tsutomu,Yamaguchi, Masaru
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p. 943 - 944
(2007/10/02)
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