Reaction #985263

Reaction equation

hydrogen

1,4,7,10-tetraazacyclododecane

benzene

→

tridecane

Conditions

Workup

1. 1
   OtherA preferred preparation of the compounds of formula IIa wherein R12

Procedure

A preferred preparation of the compounds of formula IIa wherein R12 is hydrogen is to react 1,4,7,10-tetraazacyclododecane, known in the art, with dimethylformamidedimethylacetal in the presence of benzene to yield 1,4,7,10-tetraazatricyclo-[5.5,1.0]tridecane. This “tricyclic” compound is reacted with an ethanol/water mixture to yield 1-formyl-1,4,7,10-tetraazacyclododecane. This formyl compound is then reacted with t-butyl bromoacetate to yield 1-formyl-4,7,10-triscarboxymethyl-1,4,7,10-tetraazacyclododecane, tris-t-butylester. Finally, the ester groups are removed in the presence of strong acid, such as sulfuric acid, to yield a compound of formula IIa wherein R12 is hydrogen. The most preferred methods are included in Dischino, et al., Inorg. Chem., 30, 1265, 1991.

Source