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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

Steric and Electronic Effects in the Synthesis and Regioselective Hydrolysis of Unsymmetrical Imides

Shang, Jing,Pourvali, Aysa,Cochrane, James R.,Hutton, Craig A.

, p. 1854 - 1858 (2015/12/26)

The AgI-promoted coupling reaction of thioamides and carboxylic acids is shown to be a useful method for the generation of unsymmetrical imides. The reaction proceeds efficiently with unhindered and electron-rich or neutral coupling partners, but not with hindered thioamides (such as thiopivalamides) or electron deficient thioamides (such as trifluorothioacetamides). Intriguingly, thioformamides are also ineffective coupling partners, despite having minimal steric or electronic influence. Hindered carboxylic acid coupling partners (such as pivalic acid) are tolerated, but electron deficient acids, such as trifluoroacetic acid, are ineffective coupling partners. Furthermore, an interplay of both steric and electronic effects is observed in the subsequent hydrolysis of unsymmetrical imides. Imides with a dimethoxybenzoyl group give high regioselectivity upon hydrolysis, favouring cleavage of the distal acyl group. Imides with a p-nitrobenzoyl or pivaloyl group give reversed selectivity, favouring cleavage of the proximal acyl group.

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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