Condensation of acetylacetone with formaldehyde and thiols

Acetylacetone reacted with formaldehyde and thiols in aqueous medium or in the presence of 0.1 equiv of sodium hydroxide to give the corresponding 3-[(alkylsulfanyl)methyl]pentane-2,4-diones which exist in solution as mixtures of diketone and enol tautomers. Four-component condensation of acetylacetone with formaldehyde, methanethiol, and sodium sulfide, depending on the reaction time, led to the formation of a mixture of 1,1-bis(methylsulfanylmethyl)propan-2-one with 1,1'-{3-[(methylsulfanyl)methyl]tetrahydro-2H-thiopyran-3,5-diyl}diethanone or with 8-methyl-5-(methylsulfanylmethyl)-3-thiabicyclo[3.3.1]non-7-en-6-one.