3-Oxo-4-di:methylamino-methylidene-tetra:hydro:furan aromatisers - prepd. by reacting 3-oxo-tetra:hydro-furan with aminal ester or di:methyl-formamide-acetal derivs.

摘要

New 3-oxo-4-dimethylaminomethylidene-tetrahydrofurans have formula (I): (where R1 and R2 are H, Me or Et). The use of (I) to prepare 3,4-dioxo-tetrahydrofurans having formula (IV), by oxidn. with singlet-O, is claimed. (I) can be used as aromatising materials and have a malty, bread-like odour, similar to, but weaker than, that of (IV). (IV) are known aroma materials. (I) can be prepd. economically, in good yields, e.g. 80-90%. Conversion to (IV) is quantitative. In an example, 3-oxo-2,5-dimethyl-4-dimethylamino-methylidene tetrahydrofuran was prepd. by stirring 3-oxo-2,5-dimethyl-tetrahydrofuran with either (a) tert. butoxy-bis-(dimethylamino)-methane or (b) N,N-dimethyl-formamide-dimethyl acetal.