.beta.-Oxobutyraldehyde dimethyl acetal 1,1-Dimethoxy-3-butanone 2-Butanone, 4,4-dimethoxy- 3-Ketobutyraldehyde dimethylacetal 3-Oxobutyraldehyde dimethyl acetal 4,4-Dimethoxy-2-butanone 5436-21-5 ACETYLACETALDEHYDE DIMETHYL ACETAL Acetoacetaldehyde dimethyl acetal Acetoacetaldehyde, 1-(dimethyl acetal) Acetylacetaldehyddimethylacetal NSC21538