scholarly journals Stereochemical Studies. XIV. Studies on the Neighboring Aryl Group Participation in Nitrous Acid Deaminations of L-Phenylalanine Ethyl Ester and Its p-Nitro and p-Methoxy Derivatives

1972 ◽  
Vol 20 (6) ◽  
pp. 1272-1281 ◽  
Author(s):  
KENJI KOGA ◽  
CHINC. WU ◽  
SHUNICHI YAMADA
Keyword(s):  
Ethyl Ester ◽  
Nitrous Acid ◽  
Aryl Group ◽  
Group Participation

Transformations of substituted 5-aminopyrimidines under conditions of the diazotization

1986 ◽  
Vol 51 (1) ◽  
pp. 215-233 ◽  
Author(s):  
Michal P. Nemeryuk ◽  
Andrej L. Sedov ◽  
Tamara S. Safonova ◽  
Antonín Černý ◽  
Jiří Křepelka
Keyword(s):  
Ethyl Ester ◽  
Sodium Salt ◽  
Nitrous Acid ◽  
Glycine Ethyl Ester

Reaction of nitrous acid with 4-substituted and 4,6-substituted 5-aminopyrimidines Ia-In produces 4-substituted and 4,5-disubstituted 1,2,3-triazoles IIa-IIv,resp. Under similar conditions, 2,5-diaminopyrimidines XIIa-XIId give N(7)-oxides of 2-amino-4-aralkylthiopyrimido[5,4-d]-1,2,3-triazines XIIIa-XIIId, and 5-amino-4-chloropyrimidines In and X give 2-diazocyanoacetamides XIa and XIb resp. Also described are syntheses of 5-formylaminopyrimidines XVa-XVg from glycine ethyl ester via sodium salt XVI.

Inactivation of bovine thrombin by nitrous acid

1970 ◽  
Vol 48 (4) ◽  
pp. 432-437 ◽  
Author(s):  
S. Magnusson ◽  
T. Hofmann
Keyword(s):  
Ethyl Ester ◽  
Esterase Activity ◽  
Nitrous Acid ◽  
Initial Rate ◽  
Serine Proteinases ◽  
Bovine Thrombin ◽  
Partial Protection ◽  
Isoleucine Residue ◽  
Full Protection ◽  
Prothrombin Activation

Bovine thrombin is rapidly inactivated by nitrous acid at pH 4.35 and 0°. The clotting activity falls off more rapidly than the activity towards N-benzoylarginine ethyl ester. The loss of esterase activity parallels the loss of the N-terminal isoleucine residue. N-Benzoylarginine ethyl ester gives almost full protection of the esterase activity and the N-terminal isoleucine, but only partial protection of the clotting activity. These results suggest strongly that this residue is essential for activity and indicate that thrombin resembles the pancreatic serine proteinases in this respect. The initial rate of inactivation of thrombin by nitrous acid is higher than that of trypsin, and considerably higher than that of elastase and α-chymotrypsin under the same conditions, suggesting that the N-terminal residue is more readily accessible to the reagent. The experiments strengthen the hypothesis that all mechanisms of prothrombin activation are proteolytic and suggest that they involve the liberation of the essential N-terminal isoleucine.

Sign in / Sign up

Export Citation Format

Share Document