Methanol → 2-(4-Nitrobenzyl)-1,4,7,10,13,16-hexaazacyclooctadecane

Participants

Reaction Conditions

Reaction Steps

A solution of BH3 in THF (100 mmol) was added dropwise to a stirred suspension of 3-(4-nitrobenzyl)-2,6-dioxo-1,4,7,10,13,16-hexaazacyclooctadecane (4) (10 mmol) in THF (50 ml) at 0° C. under nitrogen atmosphere. The solution was heated at reflux for 36 hours. Methanol was added slowly to the solution at 0° C. after which the solvent was removed and the residue was dissolved in methanol (50 ml); the resulting mixture was cooled at 0° C. and gaseous HCl was bubbled through the solution and then the mixture was refluxed for 12 hours. The resulting precipitate was collected washed with ether to give a white powder. The solid was dissolved in water and was loaded on a column of DOWEX 1X-8 anion-exchange resin (OH− form). The column was eluted with water; alkaline fractions were collected, and the water was removed under vacuum to give pale yellow oil. The yield was 55%.

Provenance & Evidence