Using TsOH; sodium bicarbonate (NaHCO3); dimethyl sulfide (DMS) gives an aldehyde and a dimethyl acetal Using acetic anhydride (Ac2O), triethylamine (Et3N) gives a methyl ester and an aldehyde Using TsOH; Ac2O, Et3N, gives a methyl ester and a dimethyl acetal.