ORGANIC SPECTROSCOPY INTERNATIONAL: 3-[(S)-1 -(4-bromophenyl)ethyl]-Trans-9-hydroxy-1 -oxa-3- azaspiro[5.5]undecan-2-one.

Sodium borohydride (47 mg) is added to 3-[(S)-1 -(4-bromo-phenyl)-ethyl]-1 -oxa-3- aza-spiro[5.5]undecane-2,9-dione (0.45 g) dissolved in tetrahydrofuran (4.5 mL) and water (0.6 mL) at room temperature. The mixture is stirred at room temperature for 2 h and then diluted with diethyl ether and acidified with 1 M aqueous hydrochloric acid. The organic phase is separated, washed with aqueous K₂CO3 solution and brine, and dried (Na₂SO₄). The solvent is evaporated and the residue is submitted to HPLC on reversed phase (methanol/water) to give the title compound in a ca. 9:1 mixture with 3-[(S)-1 -(4-bromophenyl)ethyl]-frans-9-hydroxy-1 -oxa-3- azaspiro[5.5]undecan-2-one. Yield: 0.25 g (55% of theory); LC (method 1 ): t_R= 3.42 min;

Mass spectrum (ESI⁺): m/z = 368/370 (Br) [M+H]⁺;

¹H NMR (400 MHz, DMSO- d₆) δ 1 .33-1 .55 (m, 4H) superimposed on 1 .47 (d, J = 7.1 Hz, 3H), 1 .55-1 .87 (m, 6H), 2.66-2.76 (m, 1 H), 3.13-3.22 (m, 1 H), 3.45 (m_c, 1 H), 4.53 (d, J = 4.5 Hz, 1 H), 5.44 (q, J = 7.1 Hz, 1 H), 7.25 (d, J = 8.4 Hz, 2H), 7.55 (d, J = 8.4 Hz, 2H).

http://www.google.com/patents/EP2585444A1?cl=en