Cyclization kinetics and mechanism of N-benzoyl-N'-(1,2-dimethyl-3-oxo-1-butenyl)thiourea

1983 ◽  
Vol 48 (2) ◽  
pp. 578-585 ◽  
Author(s):  
Jaromír Kaválek ◽  
Tomáš Potěšil ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Secondary Amines ◽  
Tertiary Amines ◽  
Cyclization Product ◽  
Ph Values ◽  
Hydroxyl Ion ◽  
Primary And Secondary Amines ◽  
Acids And Bases ◽  
Cyclization Kinetics ◽  
Kinetics Of

Cyclization kinetics of N-benzoyl-N'-(1,2-dimethyl-3-oxo-1-butenyl)thiourea have been studied in aqueous and methanolic solutions of acids and bases. In all cases the cyclization product is 4,5,6-trimethyl-2,5-dihydro-2-thioxopyrimidine or its protonated or deprotonated forms. In dilute methanolic and aqueous hydrochloric acid the substrate reacts in its monoprotonated form. The cyclization in basic media is catalyzed by methoxide or hydroxyl ion and also by primary and secondary amines at such pH values where the catalysis by lyate ion is practically insignificant. Tertiary amines and acetate ion do not catalyze the cyclization.

Reaction of arylmethylenemalonaldehydes with some nucleophiles

1987 ◽  
Vol 52 (11) ◽  
pp. 2699-2709 ◽  
Author(s):  
Dalimil Dvořák ◽  
Zdeněk Arnold
Keyword(s):  
Inorganic Anions ◽  
Secondary Amines ◽  
Tertiary Amines ◽  
Primary And Secondary Amines ◽  
Dipolar Structure

Reaction of arylmethylenemalonaldehydes with tributylphosphine and tertiary amines affords compounds of dipolar structure whereas reaction with primary and secondary amines leads to 1,4-addition products. Salts of nucleophilic inorganic anions add to arylmethylenemalonaldehydes under formation of salts of substituted malonaldehydes.

scholarly journals Kinetics of COS with primary and secondary amines in aqueous solutions

AIChE Journal ◽  
1992 ◽  
Vol 38 (2) ◽  
pp. 244-250 ◽  
Author(s):  
R. J. Littel ◽  
G. F. Versteeg ◽  
W. P. M. van Swaaij
Keyword(s):  
Aqueous Solutions ◽  
Secondary Amines ◽  
Primary And Secondary Amines ◽  
Kinetics Of

The dimerization of ammonia and amines

1950 ◽  
Vol 200 (1063) ◽  
pp. 566-572 ◽  
Keyword(s):  
Hydrogen Bonding ◽  
Virial Coefficients ◽  
Secondary Amines ◽  
Tertiary Amines ◽  
Second Virial Coefficients ◽  
Primary And Secondary Amines

The second virial coefficients of ammonia and the vapours of the primary, secondary and tertiary methylamines and ethylamines have been measured at temperatures between 20 and 130° C. The results are interpreted as showing that dimerization occurs with ammonia and with the primary and secondary amines, but not with the tertiary amines. The dimerization is attributed to hydrogen bonding, and the energy of the N—H....N bond is discussed.

Kinetics of hydrolysis and rearrangements of S-acylthiouronium salts

1982 ◽  
Vol 47 (10) ◽  
pp. 2702-2710 ◽  
Author(s):  
Jaromír Kaválek ◽  
Jaroslav Novák ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Reaction Rate ◽  
Acetyl Derivative ◽  
Reaction Products ◽  
Acid Media ◽  
Hydroxyl Ion ◽  
Hydrochloric Acid Media ◽  
Kinetics Of ◽  
Acyl Derivatives

Kinetics of transformation of S-acetyl- and S-benzoylisothiouronium chlorides have been followed, and its reaction products in dilute hydrochloric acid media and aqueous buffers have been identified. In dilute hydrochloric acid the reaction rate is pH-independent, and the acetyl derivative reacts 8 times as rapidly as the benzoyl derivative. In acetate and phosphate buffers the decomposition rate of the both derivatives increases linearly with the buffer concentration. In acetate buffers the reaction rate is pH-independent, and acetate ion reacts as a nucleophile. In phosphate buffers the rate increases with increasing pH. The reaction catalyzed by the basic buffer component produces thiourea and carboxylic acid, that catalyzed by hydroxyl ion produces N-acetyl- or N-benzoylthiourea. The solvolysis rates of both S-acyl derivatives depend on percent composition of water-methanol solvent. The maximum solvolysis rate is reached in methanol with 25% (v/v) water.

Sign in / Sign up

Export Citation Format

Share Document