Diisopropylethylamine → Biotin-PEG2-NH-Boc

Participants

Reaction Steps

A solution of vitamin H (Biotin) (2.2 g, 9 mmol), O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HBTU) (3 g, 8 mmol), and DIPEA (1.8 mL, 10 mmol) in DMF (100 mL) was stirred for 10 minutes at room temperature before being adding dropwise to a solution of N-Boc-3,6-dioxaoctane-1,8-diamine (1.5 g, 6 mmol, 1). The reaction mixture was stirred for 1 hour at room temperature, after which the DMF was removed in vacuo to give an oily residue, which was purified by flash silica gel column chromatography (CH2Cl2/CH3OH, 25/1, v/v) to afford N-Boc-N′-biotinyl-3,6-dioxaoctane-1,8-diamine (2.0 g, 90%). 1H NMR (300 MHz, CD3OD): δ 4.5 (m, 1H), 4.3 (m, 1H), 3.6 (s, 4H), 3.54 (tt, 4H), 3.39 (t, 2H), 3.26 (t, 2H), 2.9 (dd, 1H), 2.7 (d, 1H), 2.2 (t, 2H), 1.7-1.5 (m, 8H), 1.4 (s, 9H); MALDI HRMS: m/z 497.2416 [M+Na+]. Calcd for C21H38N4NaO6S 497.2410.

Provenance & Evidence