POTÁČEK, Milan, Jiří VERNER and 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 Book of Abstracts. Cavtat: 13th European Symposium on Organic Chemistry 5.-10.9.Cavtat, 2003, p. 25-26. ISBN nebylo přid+len.
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Basic information
Original name Kinetics and Mechanism of Criss-cross Cycloaddition of 1,4-Disubstituted 1,4-Diazabuta-1,3-dienes With Potassium Isocyanate and Isothiocyanate
Name in Czech Kinetika a mechanismus criss-cross cykloadice 1,4-disubstituovaných 1,4-diazabuta-1,3-dienů s isokyanátem a isothiokyanátem draselným
Authors POTÁČEK, Milan (203 Czech Republic, guarantor), Jiří VERNER (203 Czech Republic) and Jiří HANUSEK (203 Czech Republic).
Edition Cavtat, Book of Abstracts, p. 25-26, 2003.
Publisher 13th European Symposium on Organic Chemistry 5.-10.9.Cavtat
Other information
Original language English
Type of outcome Proceedings paper
Field of Study 10401 Organic chemistry
Country of publisher Croatia
Confidentiality degree is not subject to a state or trade secret
Organization unit Faculty of Science
ISBN nebylo přid+len
Keywords in English criss-cross; cycloaddition; kinetic; glyoxalimine; aromatic
Tags aromatic, criss-cross, cycloaddition, glyoxalimine, Kinetic
Changed by Changed by: prof. RNDr. Milan Potáček, CSc., učo 638. Changed: 12/6/2005 11:05.
Abstract
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.
Abstract (in Czech)
V předchozí práci jsme se zabývali syntézou 1,4-disubstituovaných 5-thioperhydroimidazo[4,5-d]imidazol-2-onů realizovaných uspořádání "one pot" cestou criss-cross cykloadice 1,4-disubstituovaných 1,4-diazabuta-1,3-dienů (glyoxaliminů)s KCNO a KCNS v kyselině octové. Ačkoliv criss-cross reakce jsou již známé, nebyly prováděné žádné kinetické studie. Proto jsme se zaměřili na sledování kinetiky s cílem dovědět se něco více o mechanismu. Výsledky byly korelovány s Hammettovými konstatami susbtituentů.
Links
MSM 143100011, plan (intention)Name: Struktura a vazebné poměry, vlastnosti a analýza syntetických a přírodních molekulových ansamblů
Investor: Ministry of Education, Youth and Sports of the CR, Structure and character of bonding, properties and analysis of synthetic and natural molecular ensembles
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