To a solution of 2 g testosterone in a mixture of 8 ml pyridine and 8 ml acetone, cooled to -10° C., was added dropwise in a nitrogen atmosphere a solution of 4 ml α-methyl-decanoyl-chloride in 12 ml acetone. The mixture was stirred for 16 hours at 0° C., whereafter 4 ml pyridine and 8 ml water were added to the mixture. The mixture was stirred for 1 hour at 0° C. and 2 hours at 45° C. and then poured out in 200 ml ice-water. Extraction with diethylether neutralisation of the extracts, evaporation of the diethylether and chromatography of the residue on silicagel with toluene/ethylacetate 8/2 gave 3.0 g testosterone α-methyl-caprate in the form of an oil with [α]D20 =+77.0° (in methylenechloride) and εmol 16.800 (λmax 240 mμ).
