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Carboxylic Acids, Carboxylic Acid Derivatives, and Acyl Substitution Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
Just as an acid chloride derived from a carboxylic acid reacts with an alcohol to produce an ester, a sulfonyl chloride reacts with an alcohol to produce a sulfonate ester, RSO2ORʹ. In this case the product is butyl ethylsulfonate, CH3CH2SO2OCH2CH2CH2CH3. What is a sulfonamide?
NaClO2-mediated preparation of pyridine-2-sulfonyl chlorides and synthesis of chiral sulfonamides
Published in Journal of Sulfur Chemistry, 2020
Dong Xu, Shiyi Yang, Aijun Gao, Zhanhui Yang
With the optimal procedure, 6-methylpyridine-2-sulfonyl chloride (2b) and 4-methylpyridine-2-sulfonyl chloride (2c) were readily synthesized in satisfactory 89% and 55% yields, respectively, from the corresponding 2-thiopyridines 1b and 1c. Although we believe that this is a good method to synthesize various substituted pyridine-2-sulfonyl chlorides, the current substrate scope is severely limited by the deficient resources of different 2-thiopyridines (see Figure 1 in the Experimental section). Other heteroarenethiols were also tested under the optimal conditions (see Figure 2 in the Experimental section). However, only the reaction of 1-methyl-1H-imidazole-2-thiol (1d) gave desired sulfonyl chloride 2d in 82% isolated yield, while the others gave desulfurative chlorination products or complex decomposed chlorination products, with complete consumption of the heteroarenethiols. Scheme 2.
Influencing factors on liquid crystalline properties of cholesterol side-chain liquid crystalline polymers without spacer: molecular weight and copolymerisation
Published in Liquid Crystals, 2019
Xiwen Yang, Sheng Chen, Shaonan Chen, Haoran Xu
Triethylamine (TEA) was distilled from 4-toluene sulfonyl chloride. Purified tetrahydrofuran (THF) was distilled from sodium benzophenone ketyl under argon and used immediately. Dichloromethane (CH2Cl2) were dried over anhydrous magnesium sulfate. Methyl acrylate (MA) was purified by neutral alumina chromatographic column. 2,2-Azobisisobutyronitrile (AIBN) was freshly recrystallised from methanol. Refined toluene and refined chlorobenzene are obtained by acid washing, alkali washing, water washing and distillation. Cholesteryl, methacryloyl chloride, acryloyl chloride, tri-n-butyltin hydride (Bu3HSn) were purchased from Energy Chemical, which were used as received without further purification. RAFT agent 4-cyanopentanoic acid dithiobenzoate (CPDB) was synthesised according to the previous reports [50,51].
Recent trends in direct mono-, di-, and tri-fluoromethyl(thiol)ation of S-H bonds
Published in Journal of Sulfur Chemistry, 2019
Akram Hosseinian, Yahya Jamal Sadeghi, Saeideh Ebrahimiasl, Aazam Monfared, Esmail Vessally
Two years later, Lu’s research team developed an efficient protocol for the synthesis of difluoromethylated disulfides 34via metal-free difluoromethylthiolation of a range of thiophenol derivatives 33 by using difluoromethanesulfonyl chloride (CHF2SO2Cl) as an inexpensive and commercially available difluoromethylthiolating agent (Scheme 19) [80]. The best conversion efficiency was obtained for the reactions containing PPh3 (3 equiv.) and NaI (20 mol%) in MeCN at room temperature. The reaction tolerated a range of versatile functional groups, such as nitro, amino, hydroxyl, and methoxy, under the present reaction conditions and provided the desired difluoromethyl disulfides 34 in moderate yields. The authors presented a mechanism for this transformation such as that outlined in Scheme 20. According to this mechanism, the reduction of difluoromethane sulfonyl chloride by PPh3 and iodide anion generates a difluoromethyl disulfide intermediate A. Next, reductive deoxygenation of another molecule of difluoromethane sulfonyl chloride by in situ generated iodotriphenylphosphonium iodide B (from the reaction of PPh3 and I2) forms difluoromethanesulfinic chloride D and Ph3P = O, and regenerates I2. Finally, a similar process via intermediate E gives difluoromethanesulfenyl chloride F, which after an electrophilic difluoromethylthiolation with aryl thiol 33 affords the corresponding difluoromethyl disulfide 34.