- Synthesis and application of a new fluorous-tagged ammonia equivalent
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A novel fluorous-tagged ammonia equivalent has been developed. It is based on a nitrogen-oxygen bond, which can be cleaved in a traceless manner by a molybdenum complex or samarium diiodide. The application in the synthesis of ureas, amides, sulfonamides, and carbamates is described. The scope of the fluo-rous N-O linker is exemplified by the synthesis of itopride, a drug used for the treatment of functional dyspepsia. Itopride was synthesized with the aid of fluorous purification methods and the product was isolated in good overall yield, with high purity.
- Nielsen, Simon D.,Smith, Garrick,Begtrup, Mikael,Kristensen, Jesper L.
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supporting information; experimental part
p. 4557 - 4566
(2010/08/20)
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- Kinetics and mechanism of the aminolysis of p-nitrophenyl N-phenylcarbamates
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Kinetic studies of the reactions of p-nitrophenyl N-phenylcarbamates with benzylamines were carried out in acetonitrile at 25·0°C. Second-order (k2) and third-order (k3) rate constants were observed for all the Y-substituted carbamates except for Y=m Cl. The relatively large magnitude of ρx (for X-substituted benzylamines) and ρY together with a positive cross-interaction constant ρxy supports a stepwise mechanism involving rate-limiting breakdown of the zwitterionic tetrahedral intermediate T±. Kinetic isotope effect studies with deuterated benzylamine (XC6H4CH2ND2) indicate that in the base-catalyzed path, k3, rate-limiting deprotonation occurs at the amino group of benzylamine within the T± intermediate. The low ΔH≠ and ΔS≠ values for the k3 process are in accord with the proposed mechanism.
- Koh, Han Joong,Kim, Ok Sun,Lee, Hai Whang,Lee, Ikchoon
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p. 725 - 730
(2007/10/03)
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- ARYLMETHYL ISOCYANATES
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Chloromethyl isocyanate reacts readily with aromatic hydrocarbons in the presence of anhydrous ferric chloride or other catalysts of the Friedel-Crafts reaction with the formation of arylmethyl isocyanates.The latter add alcohols and amines readily, being converted into the corresponding substituted urethanes and ureas.When heated in the presence of catalytic amounts of 1,3-dimethylphosphol-3-ene they give substituted carbodiimides.
- Kozhushko, B. N.,Lomakina, A. V.,Paliichuk, Yu. A.,Shokol, V. A.
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p. 654 - 660
(2007/10/02)
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