tert-butyl 2-(1,3-dioxoisoindol-2-yl)-3-oxopropanoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a solution of 166.9 g (0.57 mole) of tert-butyl 2-formyl-2-phthalimido-acetate in 1150 ml of ethanol, preheated to 60° C., there is added a solution of 160 g (0.57 mole) of alpha-amino-4-mercapto-1-methyl-4-piperidineacetic acid dihydrochloride and 235.6 g (1.73 mole) of sodium acetate (crystallized with three molecules of water) dissolved in 1150 ml of water. The reaction mixture is stirred for about ten minutes and then left to stand for 24 hours. The precipitate is filtered off, washed with water and dried. 223 g of the gamma-isomer of tert-butyl 4-carboxy-8-methyl-alpha-phthalimido-1-thia-3,8-diazaspiro-[4.5]decane-2-acetate is obtained; Yield: 81%; M.P. 276°-278° C. (decomposition). preheated to 60° C. left The precipitate is filtered off washed with water dried