Dibromomaleimide → Bromo-dansyl-cystamine maleimide

Participants

Reaction Steps

A round bottomed flask was charged with di-dansyl cystamine (48 mg, 0.08 mmol), TCEP (23 mg, 1 eq), and MeOH (10 ml). The reaction mixture was stirred at ambient temperature under argon for 3 hrs. Dibromomaleimide (41 mg, 2 eq) in MeOH (10 ml), was added to the reaction mixture. After 16 hrs, the reaction mixture was concentrated in vacuo. The residue was worked up with DCM and brine. The organic layers were combined, dried (MgSO4) and purified by flash chromatography (silica gel, 0-15% EtOAC-DCM) to yield the desired compound (17 mg, 22%). 1HNMR (CDCl3, 600 MHz), δ8.5 (1H, d J 8.5 Hz aromatic H's), δ8.2 (2H, m aromatic H's), δ7.6 (1H, s CONH), δ7.53 (2H, m, aromatic H's), δ7.15 (1H, d, J=7.4 Hz aromatic H's), δ5.30 (1H, t, J 5.6 SO2NH), δ3.38 (2H, t, J 6.3 SCH2), δ3.26 (2H, q, J 6.3 NHCH2), δ2.88 (6H, s NCH3); 13CNMR (CDCl3, 150 MHz), δ165.5, 162.9, 152.2, 142.5, 134.5, 130.95, 129.94, 129.92, 129.5, 128.7, 123.3, 119.0, 118.5, 115.4, 45.5, 43.7, 30.5; IR (cm−1) 3295 (br) 1726 (s) MS (ES+) m/z relative intensity: 485 (M, 100); Exact mass calculated for [C18H19N3O4S2Br] requires m/z 484.0000. Found 783.9982.

Provenance & Evidence