Dibromomaleimide → Di-dansyl-cystamine maleimide

Participants

Reaction Steps

A round bottomed flask was charged with di-dansyl cystamine (100 mg, 0.16 mmol), TCEP (46 mg, 1 eq) and MeOH (10 ml). The reaction mixture was stirred at ambient temperature under argon for 3 hrs. Dibromomaleimide (36 mg, 0.9 eq), in MeOH (5 ml) was then added to the reaction mixture. After 30 mins NaOAc (56 mg, 4 eq), was added to the reaction mixture and the solvent evaporated in vacuo. The residue was worked up with DCM and brine. The organic layers were combined, dried (MgSO4), filtered and concentrated in vacuo. Purification by flash chromatography (silica gel, 0-20% EtOAc-DCM) afforded the desired compound as a yellow gum (40 mg, 40%). 1HNMR (CDCl3, 600 MHz), δ8.5 (2H, d J 8.5 Hz aromatic H's), δ8.2 (4H, m aromatic H's), δ7.53 (1H, s CONH), δ7.46 (4H, m, aromatic H's), δ7.1 (2H, d, J=7.4 Hz aromatic H's), δ5.65 (2H, t, J 6.27 SO2NH), δ3.3 (4H, t, J 6.0 SCH2), δ3.17 (4H, q, J 6.0 NHCH2), δ2.8 (12H, s NCH3); 13CNMR (CDCl3, 150 MHz), 6165.9, 152.0, 136.5, 134.7, 130.7, 129.94, 129.85, 129.62, 129.57, 128.63, 123.3, 118.8, 115.4, 45.5, 43.6, 31.8; IR (cm−1) 3288 (br) 1720 (s) MS (Na+) m/z relative intensity: 736 (M, 100); Exact mass calculated for [C32H35N5O6NaS4] requires m/z 736.1368. Found 736.1390 (Na+).

Provenance & Evidence