Abstract:
The three-step manufacturing process used in the synthesis of
tenofovir disoproxil fumarate (1) was studied and optimized,
leading to a more productive and robust process. The yield was
improved from about 13% overall to 24%. Key process improve-
ments identified included implementation of a telescoped process
for the second stage that obviated the need for an extraction and
solvent exchange, and significant optimization of the final reaction,
including the beneficial effect of adding a quaternary ammonium
salt to the alkylation reaction and development of a nonaqueous
process for removal of NMP and triethylamine from the product
mixture to decrease the level of decomposition of product during
the isolation.