| abstract |
3-Formyltetrahydrothiopyrans are prepared by hydrogenating a 3-formyl-5,6-dihydro-2H-thiopyran in the presence of a catalyst containing nickel, cobalt, platinum, copper and/or silver; if necessary, the 3-formyl-5,6-dihydro-2H-thiopyrans are prepared by converting bis-(β-formylethyl) sulfides and/or 3-formyl-4-hydroxytetrahydrothiopyrans in the presence of an acidic catalyst, and, if required, these bis-(β-formylethyl) sulfides and/or 3-formyl-4-hydroxytetrahydrothiopyrans are prepared by reacting an acrolein with hydrogen sulfide (a) in the presence of a basic catalyst and of methylene chloride, aromatic hydrocarbons and/or 1,1,2-trichloroethane as solvents, and/or (b) in the presence of a carboxamide. n The compounds obtainable by the process according to the invention are useful starting materials for the preparation of dyes, drugs and pesticides. |