合成路线1

The synthesis used for the preparation of KRN2391 is as follows: The reaction of 3-cyanopyridine (I) with alcohol (ROH) in the presence of catalytic amount of alkoxide (NaOR) gives the imidate (II). The imidate (II) is converted to the cyanoimidate (III) by treatment with cyanamide in an aqueous phosphate buffer solution. The cyanoimidate (III) is coupled without further purification with nitroxyethylamine which is pre-prepared in situ from its hydrochloride (IV) and NaOH in water to provide the cyanoamidine (V). Finally, KRN2391 is obtained by salt formation of the cyanoamidine (V) with methanesulfonic acid.