Preparation of 4-Alkoxy-1-hydroxypyridine-2-thiones *

Reactions of 2-chloro-4-fluoropyridine (8), 2-chloro-4-nitropyridine (9), and their corresponding N-oxides 7 and 3 with the n-heptanolate anion were investigated in three solvents. The desired 2-chloro-4-heptyloxypyridine-N-oxide (4a) was obtained most efficiently from 3 in DMSO. A reaction of 4a with AcSNa followed by deacetylation with MeONa gave the sodium salt of 4-heptyloxy-1-hydroxypyridine-2-thione (la), which was isolated as the adamantane-1 -carboxylate O-ester 2a. Similarly, the 4-decyloxy and 4-((Z)-hex-3-enyloxy) derivatives 2b and 2c were prepared from 3.