Benzene → Tridecane

Participants

Reaction Steps

A preferred method for the preparation of the compounds of formula IIa wherein R14 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 R14 is hydrogen. The most preferred methods for the preparation of formula IIa compounds are included in Dischino, et al., Inorg. Chem,, 30, 1265, 1991.

Provenance & Evidence