2-Pyridinecarboxaldehyde → (s)-1-(9h-Fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(pyridin-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A suspension of Fmoc-Lys-OH.HCl (4.859 g, 12 mmol) and 2-pyridinecarboxaldehyde (1.285 g, 12 mmol) in DCE (100 mL) was refluxed for 30 min under nitrogen. The reaction mixture was cooled to 0° C., and treated sequentially with NaBH(OAc)3 (6.36 g, 30 mmol) and crude tert-butyl glyoxalate (2.34 g, 18 mmol) The reaction mixture was stirred at room temperature for overnight and decomposed with water. The reaction mixture was extracted with DCM. The organic layer was dried and concentrated under reduced pressure. The residue was purified by flash chromatography over silica gel to afford ((S)-1-(9H-fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(pyridin-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid (1.924 g, 28%). 1H NMR (400 MHz, CDCl3) 8.89 (d, J=4.4 Hz, 1H), 8.06 (d, J=8.0 Hz, 1H), 8.02 (d, J=7.6 Hz, 2H), 7.88 (t, J=5.8 Hz, 2H), 7.81 (d, J=7.6 Hz, 1H), 7.66 (t, J=7.4 Hz, 2H), 7.60-7.53 (m, 4H), 6.03 (d, J=7.2 Hz, 1H), 4.67-4.22 (m, 8H), 3.64-3.53 (m, 2H), 3.12 (t, J=6.8 Hz, 2H), 2.19-2.08 (m, 2H), 1.92-1.79 (m, 2H), 1.73 (s, 9H); MS (ESI), 564 (M+H)+.

Provenance & Evidence