Ethyl 3-cyclopropylprop-2-ynoate → (S)-2-(4-Bicyclo[3.3.1]non-9-yl-phenoxymethyl)-5-cyclopropyl-2,3-dihydro-oxazolo[3,2-a]pyrimidin-7-one

To a solution of (S)-5-(4-bicyclo[3.3.1]non-9-yl-phenoxymethyl)-4,5-dihydro-oxazol-2-ylamine (0.7 g, 2.23 mmol) (Example 20) in ethanol (40 mL) was added 0.462 g (3.35 mmol) of cyclopropyl-propynoic acid ethyl ester (Example 99). The reaction mixture was stirred at 82° C. for 30 minutes. The reaction mixture was concentrated and purified by chromatography on silica gel, eluting with MeOH/CH2Cl2 to afford 0.145 g of the title compound. [α]D25 −10.51 (c 0.5, CHCl3).