反应详情

The method for synthesis of 2 was modified from that of Bayer and Wilchek. In brief, biotin (1; 0.31 g, 1.26 mmol) was completely dissolved in DMF (9 mL) with gentle warming. After cooling the 1 solution to room temperature without reprecipitation, it was added to N,N′-dicyclohexylcarbodiimide (DCC; 0.26 g, 1.28 mmol) and pyridine (0.10 mL, 1.26 mmol) while stirring for 5 min at room temperature, followed by the addition of N-hydroxysuccinimide (NHS; 0.19 g, 1.65 mmol) with continuous stirring for 24 h. The reaction product was filtered and concentrated under reduced pressure. The obtained solid was redissolved in 2-propanol (50 mL) with gentle heating, cooled down to room temperature, and reprecipitated at 4° C. overnight. The product was scraped out of the glassware, washed with cold 2-propanol, and air dried to give 2 as white solid (0.36 g; 82.4%). 1H NMR (400 MHz) (DMSO) δ: 6.46 (s, 1H, CONH), 6.39 (s, 1H, CONH), 4.31 (t, 1H, CHN), 4.16 (t, 1H, CHN), 3.12 (dd, 1H, CHS), 2.83 (s, 4H, CH2 of NHS), 2.71 (d, 1H, CHHS), 2.69 (t, 2H, CH2CO), 2.59 (d, 1H, CHHS), 1.43-1.68 (m, 6H). 13C NMR (100.67 MHz) (DMSO) δ: 170.42, 162.85, 61.01, 59.28, 55.33, 30.08, 27.91, 27.68, 25.51. HRMS (ESI) calculated for C14H19N3O5S, [M+Na]+ 364.0943 (calcd.), 364.0940 (found).

1. customThe method for synthesis of 2
2. customwithout reprecipitation, it
3. stirringwith continuous stirring for 24 h
4. filtrationThe reaction product was filtered
5. concentrationconcentrated under reduced pressure
6. dissolutionThe obtained solid was redissolved in 2-propanol (50 mL) with gentle heating
7. temperaturecooled down to room temperature
8. customreprecipitated at 4° C. overnight
9. washwashed with cold 2-propanol, and air
10. customdried