PURPOSE: To contribute to a development of a new non-narcotic synthetic anodyne by forming the subject skeleton similar to a partial skeleton of morphine by reacting a specific structure thiochromane derivative with an alkylhypohalite, followed by treating the product with a base.

CONSTITUTION: A 2-thiochromane derivative having a structure expressed by formula I is reacted with an alkylhypohalite (example; t-butylhypochlorite) and the resultant product is treated with a base (preferably NaOH) to carry out deprotonation and form of 2,6-epithio-3-benzazocine skeleton expressed by formula II. For example, when a 1-(2-aminoethyl)-7-methoxy-1-methyl-2- thiochromane expressed by formula III (Me represents methyl) is used as a raw material compound, a compound expressed by formula IV having a skeleton expressed by the formula II is formed.