PROCESS FOR PREPARING 2,4-DIHYDROXYPYRIDINE AND 2,4-DIHYDROXY-3-NITROPYRIDINE

摘要

The present invention is directed to a process for preparing 2,4-dihydroxypyridine comprising heating a compound of formula A wherein R is H, alkyl or aralkyl and phosphoric acid where the ratio of phosphoric acid to water is not less than about 27 to 1 weight %. The invention is also directed to a process for preparing 2,4-dihydroxy-3-nitropyridine comprising reacting 2,4-dihydroxypyridine with nitric acid. The processes of the present invention prepare intermediates which are useful in preparing compounds which are useful for treating cardiovascular disease marked by hypertension or myocardial ischemia, ameliorating ischemic injury or myocardial infarct size, or treating hyperlipidemia or hypercholesterolemia.