1,1'-Carbonyldiimidazole → Kfm 19

Participants

Reaction Steps

2.4 g (0.014 mol) of 1,4-dioxaspiro[4,4]nonan-7-carboxylic acid are dissolved in 56 ml of methylene chloride and after the addition of 2.2 g (0.014 mol) of carbonyldiimidazole stirred for 1 hour at ambient temperature. Then 3.2 g (0.014 mol) of 5,6-diamino-1,3dipropyluracil are added and the mixture is stirred for a further 4 hours at ambient temperature. The solution is evaporated down in vacuo, the oily residue is mixed with 70 ml of water and 4.5 g of Ca(OH)2 and stirred for 1 hour at 70° C. 100 ml of 50% NaOH are added, the mixture is stirred for a further hour at 70° C. and for 16 hours at ambient temperature. Whilst being cooled with ice, the solution is adjusted to pH 6 with HCl and extracted with methylene chloride. After drying and evaporation in vacuo the combined organic phases yield a crystalline residue which is recrystallised from ethanol using activated charcoal. 0.8 g (16%) of white crystals are obtained, m.p. 147°-148° C.

Provenance & Evidence