1291293 Steroid carbonates E I DU PONT DE NEMOURS & CO. 29 May 1970 26143/70 Headings C2C and C2U The invention comprises compounds of formula wherein each of R<SP>1</SP> to R<SP>5</SP> is H or Me, and each of the bonds a, b and c is single or double, with the provisos that (i) when R<SP>3</SP> is H, at least one of a and b is a single bond, (ii) when b is a single bond, any 2-methyl group (R<SP>1</SP>) is α-oriented, (iii) when any one of R<SP>1</SP>, R<SP>2</SP> and R<SP>4</SP> is Me, the others are each H, (iv) when R<SP>2</SP> is Me, b is a double bond, and (v) when a is a single bond, the 5-hydrogen atom is α-oriented. Preparation of compounds I is by reacting an appropriate steroid 17-haloformate with an appropriate bicyclic alcohol, or by reacting an appropriate steroid 17-ol with an appropriate bicyclic haloformate. The steroidal and bicyclic haloformate starting compounds are prepared from the corresponding alcohols by reaction with carbonyl halides. 4 - Methylbicyclo[2.2.2]octane- 1 - methanol is prepared from 4 - methylbicyclo[2.2.2]octane- 1-carboxylic acid via the ethyl ester of the latter. The 17 - (4 - methylbicyclo[2.2.2]octane-1. carboxylate) of 19-nortestosterone is disclosed by way of comparison. Compounds I are said to possess myotrophic and androgenic activity, and may be made up with carriers into pharmaceutical compositions for oral and parenteral administration.