Efficient Conversion of Substituted Aryl Thioureas to 2-Aminobenzothiazoles Using Benzyltrimethylammonium Tribromide
The reaction of molecular bromine (Br2) with arylthioureas is known to produce 2-aminobenzothiazoles (Hugerschoff reaction). We show here that benzyltrimethylammonium tribromide (1, PhCH2NMe 3Br3), a stable, crystalline organic ammonium tribromide (OATB), can be readily utilized as an alternative electrophilic bromine source. It is easier to control the stoichiometry of addition with an OATB, which minimizes aromatic bromination caused by excess reagent. We have developed a direct procedure from isothiocyanates and amines using tetrabutylammonium thiocyanate (Bu4NSCN) and PhCH2NMe3Br 3 to afford functionalized 2-aminobenzothiazoles.
Synthesis of new substituted derivatives of thiourea as potential pesticides and their IR and 1H-NMR spectra
Synthesis of a six new thiourea derivatives was achieved by reaction of aromatic isothiocyanates with aminoesters. The 1H-NMR and IR spectra of the compounds were interpreted.
Brǎtulescu, George
p. 767 - 771
(2007/10/03)
Synthesis, antifungal and nematocidal activities of thioureines with an aminoester sequence
Twenty-three arylthioureines bearing β-alanine or γ-aminobutyric alkyl ester chains were synthesized for in vitro screening toward 44 strains of fungi and 2 genera of nematodes. The nitro derivatives were the most potent compounds against Aspergillus and