Tautomeric selectivity towards colchicinoids in the tosylation of colchiceine on a heterogeneous, easily removable catalyst

Organic & Biomolecular Chemistry Pub Date: 2003-07-24 DOI: 10.1039/B307650B

Abstract

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).

Graphical abstract: Tautomeric selectivity towards colchicinoids in the tosylation of colchiceine on a heterogeneous, easily removable catalyst
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