Synthetic applications of N–N linked heterocycles. Part 11. Regiospecific synthesis of dialkyl pyridin-4-yl-, quinolin-4-yl-, and isoquinolin-1-yl-phosphonates

Abstract

Treatment of N-(2,6-dimethyl-4-oxopyridin-1-yl)-pyridinium, -quinolinium, and -isoquinolinium salts with trialkyl phosphites in the presence of sodium iodide gives regiospecifically dihydro-intermediates, which may be decomposed in good yields to dialkyl pyridin-4-yl-, quinolin-4-yl-, and isoquinolin-1-yl-phosphonates respectively. The reaction may also be carried out in one step without isolating the dihydro-intermediate.