Trifluoromethanesulfonic anhydride → 4-Aminoquinoline

Participants

Reaction Steps

To prepare the compound I-1, a 4-hydroxy-[1,5]-naphthyridine, a 4-hydroxyquinazoline, a 5-hydroxyquinoxaline or a 4-hydroxyquinoline derivative can be converted into the corresponding chloro derivative by heating in phosphorous oxychloride between 40° C. and 100° C. neat or in an inert solvent like 1,2-DCE, or to the corresponding trifluoromethanesulphonyloxy derivative by reaction with trifluoromethanesulphonic anhydride, in the presence of an organic base between −40° C. and 80° C. in an aprotic solvent like DCM or THF (K. Ritter, Synthesis (1993), 735). The corresponding 4-amino-[1,5]-naphthyridine, 4-aminoquinazoline, 5-aminoquinoxaline or 4-aminoquinoline derivatives can then be obtained by reaction of the corresponding trifluoromethanesulphonyloxy derivatives with ammonia in a solvent like DCM or THF, or with n-propylamine hydrochloride in pyridine between −20° C. and 100° C. (R. Radinov, Synthesis (1986), 886). The corresponding 4-aminoquinazoline can also be obtained from its 4-chloro analogue by reaction with ammonia under the same conditions.

Provenance & Evidence