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