P 2730 (OTTO) Pyridinium chlorochromate, 98% Cas 26299-14-9 - used to oxidize an allylic methylene group. P 2730 (OTTO) Pyridinium chlorochromate, 98% Cas 26299-14-9 - used as an oxidant. In particular, it has proven to be highly effective in oxidizing primary and secondary alcohols to aldehydes and ketones, respectively.