Diisopropylethylamine → Biotin

Participants

Reaction Steps

3A-LK resin (0.1 g, 0.065 mmol) was washed with DMF. The ivDde protecting group was removed with 4% NH2NH2 in DMF (5 min, 10 min). After washing with DMF (3×5 mL), MeOH (3×15 mL), and DMF (3×5 mL), a solution of biotin-OSu (67 mg, 0.195 mmol) and DIEA (68 μL, 0.39 mmol) in DMF (2 mL) was added to the beads. The coupling proceeded at room temperature for 3 h. Kaiser test was negative. The beads were washed with DMF (5×5 mL), MeOH (3×5 mL), and DCM (3×5 mL). The beads were then dried under vacuum for 1 h before adding a cleavage mixture of 95% TFA: 2.5% water: 2.5% triisopropylsilane. The cleavage reaction was conducted at room temperature for 2 h. The liquid was collected and precipitated with diethyl ether. The crude product was purified using preparative RP-HPLC and lyophilized to give the designed product. ESI-MS, m/z 1699 (MH+).

Provenance & Evidence