79713-60-3Relevant articles and documents
Ambivalent nucleophilicity of 1,4,5-trisubstituted imidazole-2-thiones in reactions with dimethyl acetylenedicarboxylate and phenylisocyanate
Mloston,Gendek,Linden,Heimgartner
, p. 1561 - 1569 (2008/12/23)
The 1,4,5-trisubstitued 2,3-dihydro-1H-imidazole-2-thiones 1 react with electrophilic reagents via the S- or the N(3)-atom. The reaction with dimethyl acetylenedicarboxylate in methanol at room temperature occurs by the nucleophilic addition of the S-atom
First Examples of Reactions of Azole N-Oxides with Thioketones: A Novel Type of Sulfur-Transfer Reaction
Mloston, Grzegorz,Gendek, Tomasz,Heimgartner, Heinz
, p. 1585 - 1595 (2007/10/03)
The reactions of 1,4,5-trisubstituted imidazole 3-oxides 1a-k with cyclobutanethiones 5a,b in CHCl3 at room temperature give imidazole-2(3H)-thiones 9a-k in high yield. The second product formed in this reaction is 2,2,4,4-tetramethylcyclobutane-1,3-dione (6a; Scheme 2). Similar reactions occur with 1 and adamantanethione (5c) as thiocarbonyl compound, as well as with 1,2,4-triazole-4-oxide derivative 10 and 5a (Scheme 3). A reaction mechanism by a two-step formation of the formal cycloadduct of type 7 via zwitterion 16 is proposed in Scheme 5. Spontaneous decomposition of 7 yields the products of this novel sulfur-transfer reaction. The starting imidazole 3-oxides are conveniently prepared by heating a mixture of 1,3,5-trisubstituted hexahydro-1,3,5-triazines 3 and α-(hydroxyimino) ketones 2 in EtOH (cf. Scheme 1). As demonstrated in the case of 9d, a 'one-pot' procedure allows the preparation of 9 without isolation of the imidazole 3-oxides 1. The reaction of 1c with thioketene 12 leads to a mixture of four products (Scheme 4). The minor products, 9c and the ketene 15, result from an analogous sulfur-transfer reaction (Path a in Scheme 5), whereas the parent imidazole 14 and thiiranone 13 are the products of an oxygen-transfer reaction (Path b in Scheme 5).
RECYCLIZATION OF 4,5-DIPHENYLOXAZOLIN-2-ONE AND -2-THIONE UNDER THE INFLUENCE OF AMINES
Kalcheva, V. B.,Tsvetanska, L. I.
, p. 756 - 758 (2007/10/02)
4,5-Diphenyl-4-oxazolin-2-one and -2-thione undegro recyclization to 1-substituted 4,5-diphenyl-4-imidazolin-2-ones and -2-thiones, respectively, under the influence of primary amines.The action of hydrazine hydrate on the oxazolone leads to 5,6-diphenyl-1,2,3,4,-tetrahydro-1,2,4-triazin-3-one.The corresponding ureas were isolated from the reaction mixtures in a number of cases.
