Reaction Steps
EDC (2.24 g, 11.68 mmol) was added to a suspension of 2-(1H-tetrazol-1-yl)-6,7-dihydro-5H-cyclopenta[d]pyrimidine-5-carboxylic acid [I-67] (2.51 g, 9.73 mmol) and 6-fluoro-2-methyl-3-[(3S,9aR)-octahydropyrazino[2,1-c][1,4]oxazin-3-yl]benzonitrile [I-40C-1] (2.81 g, 10.21 mmol) in dichloromethane (25 mL). The reaction mixture was stirred at RT for 1.5 hours. Most of the solvent was evaporated. The residue was dissolved in EtOAc and washed with water, NaHCO3 solution and brine, dried (Na2SO4), filtered, and the solvent evaporated to afford a crude mixture of the two diastereomers. The crude product was purified on silica (220 g cartridge) with gradient elution from CH2Cl2 (solvent A) to 50% CH2Cl2:MeOH 90:10 (solvent B) to afford a mixture of the title diastereomers which were separated by chiral preparative SFC HPLC (SFC on Chiralpak IC column, Diacel Chemical Industries, LTD., 30×250 mm, 60% 2:1 MeOH:MeCN/CO2, 70 mL/min., 100 bar, sample in DCM/MeCN, 35C, 254 nm) to afford the separated aza-indane diastereomers: Isomer 2A, faster eluting, and Isomer 2B, slower eluting. Stereochemical assignment at the aza-indane chiral center was made by X-ray crystallography of the slower eluting isomer. Isomer A was dissolved in 1 mL acetonitrile and 1 eq. 1 M HCl in ether was added, and. the solid was filtered to yield the hydrochloride salt. Isomer 2A HCl salt: NMR 500 MHz (CD3OD+D2O) (mixture amide rotamers) 10.04 (s, 1H); 8.72 (s, 0.4H); 8.68 (s, 0.6H); 7.81-7.88 (m, 1H); 7.25-7.31 (m, 1H); 5.12 (t, 1H); 4.63-4.75 (m, 1.5H); 4.40-4.46 (m, 1H); 4.33-4.38 (dd, 0.5H); 4.23-4.28 (dd, 0.5H); 3.72-3.90 (m, 2H); 3.42-3.52 (m, 3H); 3.14-3.28 (m, 3H); 2.84-3.1 (m, 2H); 2.86-2.97 (m, 1H); 2.73-2.82 (m, 1H); 2.60 (s, 3H); 2.50-2.35 (m, 1H); LC/MS 512 (M+Na), 490 (M+H), 462 (M+H−N2): The HCl salt of Isomer 2B was made in a similar fashion. Isomer 2B HCl salt: NMR 500 MHz (CD3OD+D2O) (mixture amide rotamers) 10.0 (s, 1H); 8.7 (s, 1H); 7.82-7.86 (dd, 1H); 7.29 (t, 1H); 5.26 d, 1H); 4.66-4.76 (m, 1H); 4.49-4.54 (m, 1H); 4.45-4.59 (m, 1H); 4.35 (d, 0.5H); 3.90-4.03 (m, 1H); 3.76-3.88 (m, 0.5H); 3.11-3.43 (m, 5.5H); 2.88-3.00 (m, 0.5H); 2.70-2.82 (m, 1H); 2.63 (s, 3H); 2.21-2.40 (m, 1H); LC/MS 512 (M+Na), 490 (M+H), 42 (M+H−N2).
