5-[(4-aminophenyl)methyl]-3-ethyl-1,3-thiazolidine-2,4-dione

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 3-ethyl-5-(4-nitrobenzylidene)-1,3-thiazolidine-2,4-dione (3.60 g), 5% palladium carbon (5.0 g) and tetrahydrofuran (300 mL) was subjected to catalytic reduction under hydrogen pressure of 5.0 kgf·cm−2. The catalyst was removed by filtration, and the filtrate was concentrated. The residue was subjected to silica gel column chromatography, and 5-(4-aminobenzyl)-3-ethyl-1,3-thiazolidine-2,4-dione was obtained as yellow crystals (3.05 g, yield 94%) from a fraction eluted with hexane-ethyl acetate (3:1-1:1, v/v). Recrystallization thereof from ethyl acetate-hexane gave yellow prism crystals. melting point: 103-104° C. The catalyst was removed by filtration the filtrate was concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 3-ethyl-5-(4-nitrobenzylidene)-1,3-thiazolidine-2,4-dione (3.60 g), 5% palladium carbon (5.0 g) and tetrahydrofuran (300 mL) was subjected to catalytic reduction under hydrogen pressure of 5.0 kgf·cm−2. The catalyst was removed by filtration, and the filtrate was concentrated. The residue was subjected to silica gel column chromatography, and 5-(4-aminobenzyl)-3-ethyl-1,3-thiazolidine-2,4-dione was obtained as yellow crystals (3.05 g, yield 94%) from a fraction eluted with hexane-ethyl acetate (3:1-1:1, v/v). Recrystallization thereof from ethyl acetate-hexane gave yellow prism crystals. melting point: 103-104° C. The catalyst was removed by filtration the filtrate was concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 3-ethyl-5-(4-nitrobenzylidene)-1,3-thiazolidine-2,4-dione (3.60 g), 5% palladium carbon (5.0 g) and tetrahydrofuran (300 mL) was subjected to catalytic reduction under hydrogen pressure of 5.0 kgf·cm−2. The catalyst was removed by filtration, and the filtrate was concentrated. The residue was subjected to silica gel column chromatography, and 5-(4-aminobenzyl)-3-ethyl-1,3-thiazolidine-2,4-dione was obtained as yellow crystals (3.05 g, yield 94%) from a fraction eluted with hexane-ethyl acetate (3:1-1:1, v/v). Recrystallization thereof from ethyl acetate-hexane gave yellow prism crystals. melting point: 103-104° C. The catalyst was removed by filtration the filtrate was concentrated