Method for manufacturing calcobutrol

Abstract

It is disclosed a method for preparing calcobutrol, an excipient for preparing gadobutrol injections used as MRI contrast agents. the present invention provides a method for producing calcobutrol comprising: reacting lithium chloride and 4,4-dimethyl-3,5,8-trioxabicyclo[5,1,0]octane with 1,4,7,10-tetraazacyclododecane represented by the following Formula 1 to obtain a calcobutrol intermediate represented by the following Formula 2; reacting the calcobutrol intermediate represented by Formula 2 with chloroacetic acid to obtain butrol represented by the following Formula 3; and reacting butrol represented by Formula 3 with calcium ion to obtain calcobutrol represented by Formula 4 below.

Dependencies are inferred from the claim text.