With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.137076-54-1,2-(4,7,10-Tris(2-(tert-butoxy)-2-oxoethyl)-1,4,7,10-tetraazacyclododecan-1-yl)acetic acid,as a common compound, the synthetic route is as follows.
solution of DOTA tri-t-butyl ester (0.972 g, 1.70 mmol), HBTU (0.772 g, 2.04 mmol), HOBt (0.312 g, 2.04 mmol), and DIEA (0.59 niL, 5.9 mmol) in anhydrous DMF (8.0 mL) was stirred at room temperature under nitrogen for 20 minutes. The product of Part B (1.38 g, 1.70 mmol) was added in one portion. Additional HBTU (0.772 g, 2.04 mmol) was added after 1 hour and the reaction was stirred for an additional 3 hours. The reaction mixture was quenched with 10% citric acid (20 mL) and diluted with dichloromethane (30 mL). The aqueous layer was extracted with dichloromethane (3 x 30 mL). The combined organic extracts were washed consecutively with 10% citric acid (30 mL), saturated NaHCO3 (3 x 30 mL), and saturated NaCl (3 x 30 mL), dried (MgSO4), filtered, and concentrated to give a yellow oil. The oil was purified by flash chromatography over silica gel, eluting with ethyl acetate to give the title compound as a colorless oil (0.746 g, 48%). 1H NMR (4:1 CDCl3:DMSO-<4): delta 7.54 (m, 2H), 7.41 (m, 2H), 7.17 (m, 2H), 7.08 (m, 2H), 4.15 (d, 2H), 4.02 (m, IH), 2.97 (m, 2H), 2.68-2.45 (m, 24H), 2.00 (t, 2H), 1.44 (t, 2H), 1.30-1.11 (m, 31H). MS (ESI): 461.9 (100, M+2H), 922.5 (80, M+H)., 137076-54-1
As the paragraph descriping shows that 137076-54-1 is playing an increasingly important role.
Reference£º
Patent; BRISTOL-MYERS SQUIBB PHARMA COMPANY; WO2007/5491; (2007); A1;,
Metal catalyst and ligand design
Ligand Template Strategies for Catalyst Encapsulation – NCBI