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4257-83-4

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4257-83-4 Usage

Check Digit Verification of cas no

The CAS Registry Mumber 4257-83-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,2,5 and 7 respectively; the second part has 2 digits, 8 and 3 respectively.
Calculate Digit Verification of CAS Registry Number 4257-83:
(6*4)+(5*2)+(4*5)+(3*7)+(2*8)+(1*3)=94
94 % 10 = 4
So 4257-83-4 is a valid CAS Registry Number.

4257-83-4Relevant articles and documents

Rearrangement of Benzylic Trichloroacetimidates to Benzylic Trichloroacetamides

Adhikari, Arijit A.,Suzuki, Tamie,Gilbert, Reesheda T.,Linaburg, Matthew R.,Chisholm, John D.

, p. 3982 - 3989 (2017/04/11)

The rearrangement of allylic trichloroacetimidates is a well-known transformation, but the corresponding rearrangement of benzylic trichloroacetimidates has not been explored as a method for the synthesis of benzylic amines. Conditions that provide the tr

Hafnium-catalyzed direct amide formation at room temperature

Lundberg, Helena,Adolfsson, Hans

, p. 3271 - 3277 (2015/06/16)

Herein, the first example of a metal-catalyzed protocol for direct amidation of nonactivated carboxylic acids at ambient temperature (26 °C) is presented. The mild reaction conditions give rise to high yields of a range of amides in reaction times as short as 90 min, employing a commercial hafnium complex, [Hf(Cp)2Cl2], as catalyst. Amino acids are transformed into their corresponding amides without racemization, and the catalyst displays full selectivity for the amidation of carboxylic acids over esters. Electronic properties of the carboxylic acids were found to have a strong influence on the rate of the amidation reaction, and the need for a balanced amount of molecular sieves was observed to be highly important for optimal reaction outcome.

Kinetics and mechanism of aminolysis of aliphatic esters in aprotic solvents

Talvik, Agu-Tonis,Tuulmets, Ants,Vaino, Evi

, p. 747 - 750 (2007/10/03)

Kinetic studies were carried out on the aminolysis reactions of substituted aliphatic esters in a variety of aprotic solvents. The reaction rate is strongly affected by inductive and steric effects of substituents in the acyl group, rising more than 104-fold from cyanoacetate to trifluoroacetate. The quantitative treatment of solvent effects revealed a rate decrease by the polarity and π-basicity of the solvents, and also an accelerating effect of the polarizability of solvents. Cyclic transition states were assumed for both the first and second-order (in amine) reactions. Copyright

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