So I have very little experience with oxidations, but my concern is that I do not want to over-oxidize the aldehyle to a carboxylic acid. I know wit other oxidizing agents this can occur, not sure with DMP but I know it prefers the alcohol to the carbonyl so that is why I am trying to not add too much. For the same reason I would prefer to leave water out of the reaction.
I have not gotten a chance to analyze the precipitate, we don't have NMR here (Cedars-Sinai) but I am working on getting access at UCLA. I tried an extraction of the preipicate with ethyl acetate and water, keeping the organic layer and it cleaned it up, but putting the ethyl acetate layer in the cold room overnight cause some precipitate to form.
Here is my workup, I have only done it once so far:
Step 1: 3-Chloro-1,2-propanediol in water treated with slight excess of sodium azide. React under reflux for 3 hrs (I think this needs to go slightly longer, I am basing this on a previous publication by Namba et al, J. Am. Chem. Soc. 2011, 133, 11466–11469. I then extracted the product with ethyl acetate, and dried in speedvac, no further isolation
Step 2: 3-azido-1,2-propanediol (product from step 1) treated with 2 molar equivalents of DMP in CH2Cl2 and reacted for 3 hrs at RT. Added ethyl acetate to the reaction and then Extracted eith water, sat. sodium carbonate, then sat. NaCl. keeping the organic layer. About as far as I have gotten, did some TLCs on the product, there is an azide there with an Rf shift on TLC consistent with oxidation from OH to C=O, but not sure if it is the right product or something else.