Tautomeric selectivity towards colchicinoids in the tosylation of colchiceine on a heterogeneous, easily removable catalyst.
Here is presented an easy, rapid new method of tosylation of compounds containing acidic OH groups, such as tropolones and phenols, on a solid, removable catalyst, Amberlite IRA-400(OH); of special value is the preferential selectivity for the colchiceine tautomer 1a, leading to 10-tosyloxycolchicide (2)--the precursor of a variety of bioactive colchicinoids--which inverts the result of previous tosylation methodologies leading preferentially to useless 9-tosyloxyisocolchicide (3).
D002384:Catalysis; D003078:Colchicine / Q000031:analogs & derivatives* / Q000737:chemistry*; D015394:Molecular Structure; D014105:Tosyl Compounds / Q000737:chemistry*
D014105:Tosyl Compounds; C012852:colchiceine; D003078:Colchicine