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90840-21-4

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90840-21-4 Usage

Check Digit Verification of cas no

The CAS Registry Mumber 90840-21-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,8,4 and 0 respectively; the second part has 2 digits, 2 and 1 respectively.
Calculate Digit Verification of CAS Registry Number 90840-21:
(7*9)+(6*0)+(5*8)+(4*4)+(3*0)+(2*2)+(1*1)=124
124 % 10 = 4
So 90840-21-4 is a valid CAS Registry Number.

90840-21-4Relevant articles and documents

KINETICS AND MECHANISM OF BASE-CATALYZED CYCLIZATION OF SUBSTITUTED AMIDES AND NITRILES OF HYDANTOIC ACID

Machacek, Vladimir,Svobodova, Gabriela,Sterba, Vojeslav

, p. 140 - 155 (2007/10/02)

Rates of base-catalyzed cyclizations of 8 substituted derivatives of hydantoic acid amide type R3-NH(5)-CO(4)-NR2(3)-CH2(2)-CO(1)-NHR1 and 9 nitriles type R3-NH(5)-CO(4)-NR2(3)-CHR1(2)-CN have been measured in aqueous and methanolic media.The cyclization of the amides in aqueous medium is also accompanied by hydrolysis of the hydantoins formed.In some cases the hydrolysis rate constant is greater than the corresponding cyclization reaction rate constant.With the least reactive amides, the cyclization is also accompanied by hydrolysis of the amide group.The ra te of the cyclization reactions in water is higher than that in methanol (at the same concentration of the lyate ions) by the factor of 10 - 100.Substitution of hydrogen at 3 and 5 positions by methyl or phenyl groups causes an acceleration of the cyclization reaction, whereas a substitution in the amide group causes a considerable retardation.The greatest acceleration of the cyclization (by as much as 4 orders) is caused by introduction of phenyl group to the N(5) position, which is due to a substantial increase of concentration of the reactive anion.

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