To a solution of (1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalene-4-carboxylic acid 4-hydroxy-3,5-dimethyl-benzylamide (8.9 mg, 0.025 mmol) in isopropanol (1 mL) is added 2 N aq. NaOH (100 μL), NaI (1 mg, 0.007 mmol) and (S)-3-chloro-propane-1,2-diol (11.1 mg, 0.1 mmol). The reaction mixture is heated to 90° C. and shaken for 8 h before it is cooled to rt. Formic acid (0.2 mL) is added and the reaction mixture is separated by prep. HPLC to give (1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalene-4-carboxylic acid 4-((S)-2,3-dihydroxy-propoxy)-3,5-dimethyl-benzylamide (3.7 mg) as a colourless lyophilisate. LC-MS: tR=0.94 min, [M+1]+=430.27.
