2 to 4 wherein the compound of formula a is isolated as a protonated salt of the same arylsulfonic acid of which p is the arylsulfonate 6 the method of clause 5 wherein the protonated salt of the compound of formula a is isolated in amorphous or crystalline form 7 the method of any one of clauses 2 to 6 wherein the acidic medium comprises sulfuric acid 8 the method of any one of clauses 1 or 3 to 7 wherein the protonated salt is a salt of an aryl sulfonic acid 9 the method of clause 8 wherein the protonated salt is 1 4 ditosyl 1 4 7 triazacyclonone tosylate which is the toluene sulfonic acid salt of 1 4 ditosyl 1 4 7 triazacyclononane or ii 1 4 dibenzenesulfonyl 1 4 7 triazacyclonone benzenesulfonate which is the benzene sulfonic acid salt of 1 4 dibenzene sulfonyl 1 4 7 triazacyclononane 10 the method of any one preceding clause wherein the method is conducted at a reaction temperature from 100 to 160 u00b0 c 11 the method of any one preceding clause further comprising reacting a compound of formula a with a bridging element of the form zch 2 ch 2 z wherein z is a halogen selected.