1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → N-[1-(3,4-Dichlorobenzyl)-4-piperidinyl]-3-[3-(2-pyrazinyl)-1,2,4-oxadiazol-5-yl]propanamide

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Reaction Steps

To lithium 4-{[1-(3,4-dichlorobenzyl)-4-piperidinyl]amino}-5-oxobutanoate (Example 351, step ii) (0.292 g) in dichloromethane (6 ml) was added N,N-dimethylformamide (1.5 ml), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.183 g), 1-hydroxybenzotriazole hydrate (0.130 g), N′-hydroxy-2-pyrazinecarboximidamide (0.110 g) and triethylamine (0.161 g). The reaction mixture was left to stir for 24 hours before removal of dichloromethane under reduced pressure. Pyridine (5 ml) was added and heated at reflux for 5 hours. Pyridine was removed under reduced pressure followed by the addition of water. The solution was extracted three times with dichloromethane. The pooled organic phase was washed once with water, once with saturated brine and dried over magnesium sulfate. After filtration the product was azeotroped twice with toluene and was purified by RPHPLC (75%-5%, 0.1% ammonium acetate/acetonitrile). Solvent was removed under reduced pressure to give the title compound (0.067 g).

Provenance & Evidence