NEW MATERIAL:The synthetic intermediate of mevalonic acid of formula I (R1 is H, methoxyethoxymethyl, ethoxyethyl, benzyl of benzyloxymethyl; R2 is H, 1W4C alkyl or alkali metal salt; X is deuterium or tritium).

EXAMPLE: Z-Ethyl-2-deutero-2,3-epoxy-3-methyl-5-ethoxyethyloxypentanoate.

USE: Intermediate for the production of labeled mevalonic acid. The acid can be produced from an inexpensive raw material in high yield, by the use of the novel intermediate.

PREPARATION: For example, the alcohol group of 3-butyn-1-o1 is protected, and the alcohol is treated with a chlorocarbonic acid ester in the presence of a strong base. The treated product is made to react with copper iodide and methyl lithium, treated with labeling water, and epoxidized to obtain one of the compound of formula I . The obtained compound of formula I is reduced and converted to an alcohol to obtain the mevalonic acid derivative of formula II.