Preparation of various enantiomerically pure (benzotriazol-1-yl)- and (benzotriazol-2-yl)-alkan-2-ols

Domino Knoevenagel/Michael addition/C-acylation reaction. Synthesis of 1,3-cyclohexane-1,3-diones

“…The readily available acetone derivatives, namely 1,3-bis-benzotriazol-1-ylpropan-2-one 1 21 and 1-benzotriazol-1-ylpropan-2-one 2 22 were used in the present research as the active methylene compounds. All reactions were carried out at 60 ºC in a DMF solution under inert gas with triethylamine added as the catalyst.…”

“…A mixture of dibenzotriazolacetone 21 or benzotriazolacetone 22 (1 mmol), Meldrum's acid (0,144g, 1 mmol), appropriate aldehyde (1 mmol) and triethylamine (1 mL) in anhydrous DMF (5 mL) was stirred and heated under argon blanket at 60 ºC for a few hours. The reaction progress was controlled by thin-layer chromatography (silica gel, hexane/ethyl acetate, 1:1).…”

Synthesis of new optically pure tetrabromobenzotriazole derivatives via lipase-catalyzed transesterification

“…An enantioselective resolution of similar compounds has been previously reported [19]. Racemic N-substituted 1H-and 2H-benzotriazoles with hydroxyl group in the side chain were subjected to a kinetic resolution through a lipase-catalyzed transesterification under different conditions [19]. Similar structure of the molecules and high enantioselectivity factors prompted us to apply this method to the TBBt derivatives.…”

“…Decreasing temperature may result in higher enantioselectivity, but lower reaction rate and vice versa [19]. Therefore we carried out reactions at lower (4 • C, 10 • C and 16 • C) and higher (30 • C) temperature ( Table 5).…”

“…Many factors have an impact on the results of the reaction: lipase type [15][16][17][18], temperature [19], solvent [20][21][22], water content [23] as well as acyl donor [24,25], changing the reaction enantioselectivity factor E [26] or even reversing enantiopreference of the catalyst [23,27]. An enantioselective resolution of similar compounds has been previously reported [19]. Racemic N-substituted 1H-and 2H-benzotriazoles with hydroxyl group in the side chain were subjected to a kinetic resolution through a lipase-catalyzed transesterification under different conditions [19].…”