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@inproceedings{488616,
author = {Potáček, Milan and Verner, Jiří and Hanusek, Jiří},
address = {Cavtat},
booktitle = {Book of Abstracts},
keywords = {criss-cross; cycloaddition; kinetic; glyoxalimine; aromatic},
language = {eng},
location = {Cavtat},
isbn = {nebylo přid+len},
pages = {25-26},
publisher = {13th European Symposium on Organic Chemistry 5.-10.9.Cavtat},
title = {Kinetics and Mechanism of Criss-cross Cycloaddition of 1,4-Disubstituted 1,4-Diazabuta-1,3-dienes With Potassium Isocyanate and Isothiocyanate},
year = {2003}
}
TY - JOUR
ID - 488616
AU - Potáček, Milan - Verner, Jiří - Hanusek, Jiří
PY - 2003
TI - Kinetics and Mechanism of Criss-cross Cycloaddition of 1,4-Disubstituted 1,4-Diazabuta-1,3-dienes With Potassium Isocyanate and Isothiocyanate
PB - 13th European Symposium on Organic Chemistry 5.-10.9.Cavtat
CY - Cavtat
SN - nebylo přid+len
KW - criss-cross
KW - cycloaddition
KW - kinetic
KW - glyoxalimine
KW - aromatic
N2 - In our previous work we have dealt with the synthesis1 of 1,4-disubstituted-5-thioperhydroimidazo[4,5-d]imidazol-2-ones by one pot criss-cross cycloaddition of 1,4-disubstituted 1,4-diazabuta-1,3-dienes (glyoxalimines) with potassium isocyanate and isothiocyanate in glacial acetic acid (Scheme). Although the phenomenon of criss-cross cycloaddition reactions is known for a long time (first reported by Bailey2 in 1917) almost no kinetics study of this type of reaction have been done and only suggestions for reaction mechanism can be found in the literature3,4. Therefore we have focused our attention on kinetics and mechanism of reaction mentioned above. It was found that the observed rate constant increases linearly with the concentration of KNCX (X = O,S) and the slope is giving bimolecular rate constant k which varies from 6.7 to 36.6 l.mol.s-1 depending on substitution at benzene ring. From slopes of Hammett correlation (positive value for KNCS and negative for KNCO) it is evident that reaction is strongly affected by nucleophilicity of NCX anion.
ER -
POTÁČEK, Milan, Jiří VERNER a Jiří HANUSEK. Kinetics and Mechanism of Criss-cross Cycloaddition of 1,4-Disubstituted 1,4-Diazabuta-1,3-dienes With Potassium Isocyanate and Isothiocyanate. In \textit{Book of Abstracts}. Cavtat: 13th European Symposium on Organic Chemistry 5.-10.9.Cavtat, 2003, s.~25-26. ISBN~nebylo~přid+len.
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