1,1'-Carbonyldiimidazole → HCID 54213453, compound

Participants

Reaction Steps

3.6 g (19.1 mmol) of 5-phenyl-4-oxazolecarboxylic acid were added portionwise to a suspension of 3.1 g (19.1 mmol) of 1,1'-carbonyldiimidazole in 20 ml of dry tetrahydro- furan, whereby a brown solution formed with the evolution of gas. After a reaction period of 15 minutes at 20° 3.05 g (19.0 mmol) of t-butyl (2-aminoethyl)carbamate in 10 ml of dry tetrahydrofuran were added dropwise (slight warming) and the reaction mixture was stirred for a further 30 minutes. Thereafter, the reaction mixture was evaporated under reduced pressure and the residue was partitioned between methylene chloride and 0.1N hydrochloric acid. After washing neutral with saturated sodium chloride solution the organic phase was dried over magnesium sulfate and evaporated, whereby there were obtained 5.8 g (92%) of t-butyl [2-(5-phenyl-4-oxazole-carboxamido)ethyl]-carbamate which were stirred at 20° for 20 minutes in 20 ml of trifluoroacetic acid. Thereafter, the reaction mixture was evaporated under reduced pressure. The residue was dissolved in 5 mo of methanol and treated with 10 ml of 5.5N hydrogen chloride in methanol. Filtration of the separated crystals yielded 2.4 g (51%) of N-(2-aminoethyl)-5-phenyl-4-oxazole-carboxamide hydrochloride as white crystals, melting point 257° (dec.). The 5-phenyl-4-oxazolecarboxylic acid used as the starting material was prepared as follows:

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