Oxidant/Solvent-Controlled I2-Catalyzed Domino Annulation for Selective Synthesis of 2-Aroylbenzothiazoles and 2-Arylbenzothiazoles under Metal-Free Conditions
A simple and practical domino protocol for the selective synthesis of 2-aroylbenzothiazoles and 2-aryl benzothiazoles catalyzed by I2 is developed under metal-free conditions. The reaction outcomes are exclusively controlled by the reaction oxidant/medium. With DMSO employed as both the solvent and the oxidant, an oxidation of aromatic methyl ketones takes precedence over the condensation with 2-aminobenzenethiols. On the other hand, when the reaction was carried out in PhNO2 or in 1,4-dioxane containing PhNO2, the condensation of aromatic methyl ketones with 2-aminobenzenethiols has priority to form imines which is followed by an oxidation of the methyl group from ketones to afford 2-arylbenzothiazoles as a sole product. The PhNO2/I2 co-catalytic system is proposed first time.
Solvent-free synthesis of benzothiazolines in the presence of alumina
o-Aminothiophenol reacted with ketones and β-keto esters in the presence of alumina under mild and solvent-free conditions to afford the corresponding benzothiazolines in high yields. Alumina can be reused for subsequent reactions without any loss of the
A RING EXPANSION METHOD FOR THE PREPARATION OF 2,3-DIHYDRO-1,4-BENZOTHIAZINES FROM 2-ARYL-2,3-DIHYDROBENZOTHIAZOLES
In the presence of KF in dimethylformamide (DMF) 2-aryl-2,3-dihydrobenzothiazoles react with α-haloketones to provide in good yield 2,3-dihydro-2,3-disubstituted-1,4-benzothiazines.
Mashraqui, Sabir H.,Kellogg, Richard M.
p. 1457 - 1460
(2007/10/02)
Reactions of Triorganogermanium (IV) Chlorides with 2,2-Disubstituted Benzothiazolines
New volatile compounds of triorganogermanium(IV) with sulphur containing schiff bases have been synthesised by the reactions of triorganogermanium(IV) halides with 2,2-disubstituted benzothiazolines.These have been characterised as pentacoordinate complex
Jain, Leela,Saraswat, B. S.,Mehrotra, R. C.
p. 583 - 585
(2007/10/02)
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