138944-20-4 Usage
Check Digit Verification of cas no
The CAS Registry Mumber 138944-20-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,8,9,4 and 4 respectively; the second part has 2 digits, 2 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 138944-20:
(8*1)+(7*3)+(6*8)+(5*9)+(4*4)+(3*4)+(2*2)+(1*0)=154
154 % 10 = 4
So 138944-20-4 is a valid CAS Registry Number.
138944-20-4Relevant articles and documents
Directed metalation and new synthetic transformations of 5-aryltetrazoles
Flippin, Lee A.
, p. 6857 - 6860 (2007/10/02)
The tetrazole moiety is a useful directing group for the lithiation of 5-aryl substituents. Dilithiated 5-aryltetrazoles generally react with alkyl halides and aldehydes to give substitution and addition products, respectively.