Dicyclohexylcarbodiimide → Diisopropylamine

Participants

Reaction Steps

For example, an imidazopyrimidine (7, Step 4) can be prepared from an appropriate α-bromo or α-chloro ketone with 2-aminopyrimidine in a polar protic solvent such as isopropanol or ethanol or a non-polar solvent such as toluene with or without a base such as sodium bicarbonate to give an imidazo[1,2-a]pyrimidine (7). The imidazo[1,2-a]pyrimidine (7) can be converted to the desired imidazol-2-amine (8, Step 5) with hydrazine, hydrazine hydrate, or hydrazine hydrochloride or hydroxylamine. The primary amino group of compound 8 can then be coupled with the carboxylic acid of compound 5 in Scheme 1 using coupling agents to give compounds of Formula Ia, I and II. Common coupling conditions involve using a coupling agent such as benzotriazol-1-yloxy-tris(dimethylamino)-phosphonium hexafluorophosphate, propylphosphonic anhydride, dicylohexylcarbodiimide, o-benzotriazol-1-yl-N,N,N′N′-tetramethyluronium tetrafluoroborate, and 2-(1H-7-azabenzotriazol-1-yl)--1,1,3,3-tetramethyl uronium hexafluorophosphate methanaminium and an organic base such as N-methylmorpholine or diisopropylamine to give compounds of formula Ia.

Provenance & Evidence