A synthesis of the haptens of the long acting oral contraceptive quinestrol and its metabolic product ethynylestradiol has been described.Norlutin was used as the Starting material and oxidized according to the method of yeild the ld the 6-oso-ethynylestradiol,which was than reached with cyclopentyl bromide to give-the 6-oxo-ethynylestradiol.Both 6-oxo-ethynylestradiol and 6-oxo-quinestrol were then reacted respectively with carhoxy-methoxylamine hemihydro-chloride to give the corresponding 6-(O-carboxymethyl) oxime derivatives of 6-oxo-quinestrol and 6-oxo-ethynylestradiol.