Thioureido-acetamide

A number of solid thiohydantoins 274 react quantitatively and specifically at the C(=0)-N bond with gaseous aliphatic amines to give the versatile [96] thioureido-acetamides 275 [31]. These reactions proceed equally well with sec-... 

Keywords thiohydantoin, amine, ring opening, waste-free, gas-solid reaction, thioureido-acetamide... 

The solid thioureido-acetamide la-c (2.00 mmol) and solid phenacyl bromide 2 (398 mg, 2.00 mmol) were ball-milled in a Retsch MM 2000 mill with a 10-mL beaker (two balls out of stainless steel) at room temperature for 30 min. After drying at 0.01 bar at 80 °C quantitative yields of the pure (hydro)bromides 3a-c were obtained in all cases. The salts were washed with 5% Na2C03 solution to afford the free bases 4a-c in pure form in 98, 99 and 98% yield, respectively. 

The thioureido-acetamide lb (2.00 mmol) and 2 (2.00 mmol) were weighed into a 10-mL ball-mill vessel. The mixture became immediately solid and was ball-milled at 25 Hz for 1 h. 3b remained insoluble in hot ethyl acetate whereas 4b dissolved and was separated by filtration. 3b was recrystallized from DMSO (3b, yield 54%). The ethyl acetate extract was evaporated to dryness and the crude solid recrystallized from ethanol (4b, yield 26%). 

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