1-Fmoc-piperazine hydrobromide

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-{(4-pentyl-benzyl)-[3-(4-trifluoromethyl-phenyl)-acryloyl]-amino}-(S)-3-phenyl-propionic acid (1.5 g, 2.86 mmol) and TBTU (1.1 g, 3.43 mmol) was dissolved in acetonitrile (30 mL) and DIPEA (1.5 mL, 8.6 mmol) and stirred at rt for 5 min, followed by the addition of Fmoc-piperazine hydrobromide (1.22 g, 3.15 mmol). The reaction mixture was stirred at rt for 16 h and concentrated under reduced pressure. The residue was dissolved in EtOAc (150 ml) and washed with brine (100 ml), dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (silicagel, EtOAc/heptane=3/7) to give 1.75 g (75%) of 4-(2-{(4-pentyl-benzyl)-[3-(4-trifluoromethyl-phenyl)-acryloyl]-amino}-(S)-3-phenyl-propionyl)-piperazine-1-carboxylic acid 9H-fluoren-9-ylmethyl ester. LC-MS: tR=1.25 min; [M+H]+=814.5. concentrated under reduced pressure The residue was dissolved in EtOAc (150 ml) washed with brine (100 ml) dried over magnesium sulfate filtered concentrated under reduced pressure The crude product was purified by column chromatography (silicagel, EtOAc/heptane=3/7)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-{(4-pentyl-benzyl)-[3-(4-trifluoromethyl-phenyl)-acryloyl]-amino}-(S)-3-phenyl-propionic acid (1.5 g, 2.86 mmol) and TBTU (1.1 g, 3.43 mmol) was dissolved in acetonitrile (30 mL) and DIPEA (1.5 mL, 8.6 mmol) and stirred at rt for 5 min, followed by the addition of Fmoc-piperazine hydrobromide (1.22 g, 3.15 mmol). The reaction mixture was stirred at rt for 16 h and concentrated under reduced pressure. The residue was dissolved in EtOAc (150 ml) and washed with brine (100 ml), dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (silicagel, EtOAc/heptane=3/7) to give 1.75 g (75%) of 4-(2-{(4-pentyl-benzyl)-[3-(4-trifluoromethyl-phenyl)-acryloyl]-amino}-(S)-3-phenyl-propionyl)-piperazine-1-carboxylic acid 9H-fluoren-9-ylmethyl ester. LC-MS: tR=1.25 min; [M+H]+=814.5. concentrated under reduced pressure The residue was dissolved in EtOAc (150 ml) washed with brine (100 ml) dried over magnesium sulfate filtered concentrated under reduced pressure The crude product was purified by column chromatography (silicagel, EtOAc/heptane=3/7)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 1.47 g (4.7 mmol) N-Fmoc-piperazine (obtained from N-Fmoc-piperazine hydrobromide by treatment with aqueous NaHCO3 and extraction with TBME, drying the organic layer over Na2SO4 and evaporation under reduced pressure at <30° C.) in 18 ml CH2Cl2 at 0° C. was added dropwise to a solution of 1.51 g (4.7 mmol) (RS)-carbonic acid 4-benzyloxy-benzyl ester 1-chloro-ethyl ester in 57 ml of CH2Cl2. The reaction is slightly exothermic and a colourless precipitate is formed. After 1 h at 0° C. the mixture was allowed to warm to rt and stirred for further 62 h. Then the reaction is quenched with 2.35 ml 4M K2CO3, filtered over a plug of Na2SO4 and evaporated. The crude product (2.67 g) was purified by flash-chromatography on silica gel with hexane/AcOEt 50:50 as eluent: 1.54 g (60%) RO-72-0160/000 as yellow solid. IR (Nujol): 1699 cm−1. 1H-NMR (CDCl3): 3.25–3.60 br, 8H; 4.23 t, J=6.4 Hz, 1H; 4.48 d, J=6.4 Hz, 2H; 5.06 s and 5.07 s, 4H; 6.97 d, J=8.4 Hz, 2H, 7.26–7.45, m 11H, 7.55 d, J=7.6 Hz, 2H and 7.76 d, J=7.6 Hz, 2H. MS (ISP): 566.4 (M+NH4)+; 571.4 (M+Na)+.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-{(4-pentyl-benzyl)-[3-(4-trifluoromethyl-phenyl)-acryloyl]-amino}-(S)-3-phenyl-propionic acid (1.5 g, 2.86 mmol) and TBTU (1.1 g, 3.43 mmol) was dissolved in acetonitrile (30 mL) and DIPEA (1.5 mL, 8.6 mmol) and stirred at rt for 5 min, followed by the addition of Fmoc-piperazine hydrobromide (1.22 g, 3.15 mmol). The reaction mixture was stirred at rt for 16 h and concentrated under reduced pressure. The residue was dissolved in EtOAc (150 ml) and washed with brine (100 ml), dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (silicagel, EtOAc/heptane=3/7) to give 1.75 g (75%) of 4-(2-{(4-pentyl-benzyl)-[3-(4-trifluoromethyl-phenyl)-acryloyl]-amino}-(S)-3-phenyl-propionyl)-piperazine-1-carboxylic acid 9H-fluoren-9-ylmethyl ester. LC-MS: tR=1.25 min; [M+H]+=814.5. concentrated under reduced pressure The residue was dissolved in EtOAc (150 ml) washed with brine (100 ml) dried over magnesium sulfate filtered concentrated under reduced pressure The crude product was purified by column chromatography (silicagel, EtOAc/heptane=3/7)