NEW MATERIAL:The compound of formulaI(R is alkyl or alkenyl).

EXAMPLE: 4-Methylthio-2-methylfuran.

USE: A lasting perfumery and perfume modifier. It has meatlike, spicy, or onion- like flavor, and excellent durability, and is useful in a wide field such as food, drink, cosmetic, and health, hygienic or pharmaceutical goods, etc.

PROCESS: The compound of formula 1 can be prepared by contacting 2-methyl-2, 5-dimethoxy-2,5-dihydrofuran of formula 6 (R1 is alkyl) with water to obtain 4- oxo-2-pentenal of formula 5, reacting the product with an alkane or alkenethiol of formula RSH in the presence of a base (e.g. pyridine, piperidine, etc.), and reacting the resultant 4-oxo-3-alkylthio-pentanal dialkyl acetal of formula 2 with H2SO4, etc.