The oil prepared in Step 10 (1.5 g, 5.95 mmol) was dissolved under argon in methanol (22 mL). To this solution was added 2-dimethylaminoethanethiol hydrochloride (843 mg, 5.95 mmol), piperidine (0.78 mL, 7.85 mmol) and benzyltrimethylammonium hydroxide (0.25 mL, 0.6 mmol), and the mixture was stirred at room temperature for 16 hours. The solvent was removed on a rotary evaporator and then the residue was purified by flash chromotography on silica gel, eluting with 20:1 CH2Cl2 :MeOH to give the pure title compound (0.5 g, 24% yield). 1H NMR: 300 MHz spectrum consistent with proposed structure. Anal: calcd. for C21H27NO2S+0.2H2O: C, 69.85; H, 7.65; N, 3.88. Found: C, 69.58; H, 7.60; N, 3.98.
