3-(Difluoromethyl)-2-fluoro-4-hydroxypyridine-6-sulfonyl chloride
2-(Difluoromethyl)-6-fluoro-3-hydroxypyridine-5-sulfonyl chloride
2-(Difluoromethyl)-4-fluoro-6-hydroxypyridine-3-sulfonyl chloride
3-(Difluoromethyl)-2-fluoro-5-methoxypyridine-4-sulfonyl chloride