98095-86-4Relevant articles and documents
KINETICS AND MECHANISM OF REARRANGEMENT AND METHANOLYSIS OF ACYLPHENYLTHIOUREAS
Kavalek, Jaromir,Jirman, Josef,Sterba, Vojeslav
, p. 766 - 778 (2007/10/02)
S-Acyl-1-phenylthioureas and their 3-methyl derivatives are rearranged to 1-acyl derivatives of thiourea in methanolic solution.The rearrangement of the 1-acyl-1-phenyl derivative to the thermodynamically more stable 3-acyl derivative is subject to specific base catalysis.The rearrangement of acetyl group is about 2 orders of magnitude slower than that of benzoyl group. 1-Acetyl-1-phenylthiourea undergoes base-catalyzed methanolysis (giving phenylthiourea and methyl acetate) instead of the rearrangement.The methanolysis rates of 1-acyl-3-phenylthioureas and their N-methyl derivatives have been measured.The acetylthioureas react at most 3 x faster than the benzoyl derivatives.The methyl group at the nitrogen adjacent to acyl group accelerates the solvolysis by almost 2 orders of magnitude; the methyl group at the other nitrogen atom retards the solvolysis by almost 1 order of magnitude.Replacement of hydrogen atom by methyl group at the phenyl-substituted nitrogen increases acidity of the phenylacetylthiourea by 2 orders of magnitude.The same replacement at the benzoyl-substituted nitrogen increases the acidity by 3 orders of magnitude, the increase in the case of the acetyl derivative being as large as 4 orders of magnitude.
