In the present work, which is a continuation of investigations already carried out in [i, 7], results are presented of a study of the reaction of 17~-hydroxy-3-oxoandrosta-l,4diene-178-carbonitrile (IV) with methyl-lithium. In the literature [5-I0], similar reactions have been described for 17~-hydroxy-3-oxo-androst-4-ene-178-carbonitrile (Ib). To selectively carry out nucleophilic addition reaction of methyl-lithium at the nitrile group and to obtain pregnane derivatives, the carbonyl group at C 3 is protected by the formation of ketals~ enamines and enol ethers. In the case of cyanohydrin of androstadienedione IV, no effective protection for a "crosswise" congugated system was found in the literature [9]. These At, 4ketones do not form ketals, thioketals, enamines and enol ethers. Although obtainable in high yields, 3-methoxyimines and semicarbazones cannot be used, since their hydrolysis is usually difficult and ineffective. It is known [2] that under Grignard reaction conditions, at lowtemperatures (-15 - 0~ and at a minimal excess of methylmagnesium bromide, this dienone system is less reactive than the A1e-20-oxo group conjugated with the double bond. Thus, 6-methyl-steroids can be obtained without preliminary protection of the 3-keto group. The aim of the present work was to compare the reactivities of the nitrile group and the dienone system under conditions of a condensation reaction with methyl-lithium to evaluate the possible use of androstadienedione (ADD, V~ for preparing pregnanes by the method of a cyanohydrin synthesis. To protect the 17~-hydroxy group, butoxyethyl ethers II and VI were prepared. In the reaction of the corresponding cyanohydrins Ia and IV with butyl vinyl ether, a mixture of diastereomers is formed, with, according to PMR spectroscopy data, practically equal contents of R- and S-isomers. This mixture was used without isolation at the condensation stage with an ether solution of methyl-lithium. In the case of 17~-(l-butoxy)et hoxy-3,3-ethylenedioxyandrost-5-ene-178 carbonitrile (If), the nucleophilic addition reaction at the nitrile group was carried out under conditions~ milder than those described in [5, I0]. Low temperatures (-30~ were used, while the acetal CH~