A straightforward preparation of primary alkyl triflates and their utilityin the synthesis of derivatives of ethidium

The reaction of primary alcohols with trifluoromethanesulfonic anhydride in the presence of poly(4-vinylpyridine) [or poly(2,6-di-tert-butyl-4-vinylpy ridine)] allows the isolation of the corresponding alkyl triflates in good yields. The quaternisation of 3,8-bis(ethoxycarbonylamino)-6-phenylphenanth ridine (1) using these alkyl triflates was found to proceed smoothly at roo m temperature in nitrobenzene or chlorobenzene. Deprotection of these quate rnary compounds using concentrated hydrobromic acid was found to be a more useful procedure than the previously reported use of concentrated sulfuric acid. The synthesis of the novel ethidium derivative 3,8-diamino-5-(5-amino pentyl)-6-phenylphenanthridinium bromide (12) is reported.