- 2,2,2-Trifluroenthanol promoted synthesis of unsymmetrical ureas from dioxazolones and amines via tandem lossen rearrangement/condensation process
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A 2,2,2-trifluroenthanol (TFE) promoted synthesis of unsymmetric ureas was described. This approach enabled the construction of a variety of ureas from the readily prepared and easy-to-handle dioxazolones and amines via tandem Lossen rearrangement/condensation process. The reaction featured mild conditions for the urea synthesis under metal-free conditions, which was successively applied in the scale-up synthesis of herbicides Monuro and Isoproturon.
- Li, Jian,He, Wang,Lei, Pan,Song, Jiacheng,Huo, Jiyou,Wei, Hongbo,Bai, Hongjin,Xie, Weiqing
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supporting information
p. 3590 - 3600
(2021/10/07)
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- A Novel C–N Migration Rearrangement Based on N–F Compounds for the Synthesis of N-Alkyl Diaryl Ureas
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A novel rearrangement reaction based on the structure of N-fluoro-N-(phenylsulfonyl) benzamides (FPSBA) was developed. In the presence of base, unsymmetrical N-alkyl diaryl ureas were obtained in good yields which were accomplished through secondary alkyl phenylamines initiated 1,2-phenyl-shift migration rearrangement of N-fluoro-N-(phenylsulfonyl) benzamides. The reaction was carried out without using traditional, highly toxic reagents and noble metals. Whereas without rearrangement occurrence for primary phenylamines and aliphatic amines, normal amides and N-(phenylsulfonyl) benzamides were afforded respectively. Nitrene and phenyl isocyanate included process were prevented and a secondary alkyl phenylamine initiated vicinal SN2' reaction occurred. This rearrangement reaction features an interesting reaction mechanism, mild reaction conditions, simple operation, and useful products.
- Zhao, Yi-Xiao,Xie, Tian,Yang, San-Ke,Yang, Xian-Jin
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p. 437 - 445
(2020/01/22)
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- Synthesis of unsymmetrical phenylurea derivatives via oxidative cross coupling of aryl formamides with amines under metal-free conditions
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A new synthetic approach for phenylurea derivatives involving the cross coupling of N-aryl formamides with amines through the formation of isocyanate intermediates in the presence of hypervalent iodine reagents is described.
- Reddy, Nagireddy Veera,Kumar, Pailla Santhosh,Reddy, Peddi Sudhir,Kantam, Mannepalli Lakshmi,Reddy, Kallu Rajender
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p. 805 - 809
(2015/02/19)
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- Radical fixation of functionalized carbon resources: α-sp 3C - H carbamoylation of tertiary amines with aryl isocyanates
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A new carbamoylation of tertiary amines is reported. This rare C - H transformation features the direct generation of α-aminoalkyl radicals from tertiary amines, followed by the addition of the resultant nucleophilic radicals to isocyanates, enabling unique access to N,N-dialkylated amino acid derivatives. The authors put forward a mechanistic proposal that is based on the isolation of borinamides produced by capturing nitrogen radical intermediates with Et3B. The present transformation provides a novel one-step process for producing mepivacaine, a clinically important local anesthetic, from readily available materials.
- Yoshimitsu, Takehiko,Matsuda, Kenichi,Nagaoka, Hiroto,Tsukamoto, Koji,Tanaka, Tetsuaki
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p. 5115 - 5118
(2008/03/28)
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- Molecular Scaffolds I: Intramolecular Hydrogen Bonding in a Family of Di- and Triureas
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Di- and triurea derivatives 1 can be prepared by an iterative procedure and are found to exist in intramolecularly hydrogen bonded 10-membered ring conformations, in which substituents R1 and R2 and hydrogen bonding control the direction of the urea carbonyl groups.
- Nowick, James S.,Powell, Noel A.,Martinez, Eduardo J.,Smith, Eric M.,Noronha, Glenn
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p. 3763 - 3765
(2007/10/02)
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- NOVEL DESULFURIZATION OF THIOCARBONYL COMPOUNDS INTO THEIR CORRESPONDING OXO-DERIVATIVES USING A PEROXY-SULFUR INTERMEDIATE GENERATED FROM 2-NITROBENZENESULFONYL CHLORIDE AND SUPEROXIDE ANION.
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Thiocarbonyl compounds such as substituted-thioureas, -thioamides, and -thiocarbamates were found to react with a peroxysulfur intermediate (3) which is generated by the treatment of 2-nitrobenzenesulfonyl chloride with potassium superoxide to convert into the corresponding carbonyl compounds in quantitative yield at -30 oC in acetonitrile.
- Kim, Yong Hae,Chung, Bong Chul,Chang, Hae Sung
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p. 1079 - 1082
(2007/10/02)
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- FACILE CONVERSION OF 1,3-DISUBSTITUTED THIOUREAS TO THE CORRESPONDING UREAS BY SUPEROXIDE RADICAL ANION (O2.-) IN DIMETHYL SULFOXIDE
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Treatment of 1,3-disubstituted thioureas with superoxide radical anion (O2.-) at 20 deg C in dimethyl sulfoxide resulted in the formation of 1,3-disubstituted ureas in excellent yields.The desulfurization appears to proceed by the formation of peroxy-sulfur intermediates such as peroxy-sulfenate, -sulfinate and/or -sulfonate.
- KIM, Yong Hae,YON, Gyu Hwan,KIM, Hyung Jin
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p. 309 - 312
(2007/10/02)
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