H 1637 (OTTO) 5-Hydroxymethyl furfural, 98% Cas 67-47-0 - used as an intermediate of OMBF (5,5'-oxydimethylenebis(2- furfural)), crown ethers. H 1637 (otto) 5-Hydroxymethyl furfural, 98% Cas 67-47-0 - used in organic synthesis to prepare dialdehydes, glycols, ethers, amino alcohols and acetals. It acts as an antioxidant found in some fruit juices and caramel products.