Carbon Dioxide → HCID 20071293, compound

Participants

Reaction Steps

544 mg (2 mmol) Of 2,4-dibromoglutaric anhydride, 0.5 ml of CH2Cl2, and 85 μl (2.1 mmol) of methanol are stirred in a capped vial at room temperature for 5.5 hours, after which time the IR spectrum indicates the absence of starting materials. 5 ml of benzene and 10 μl of DMF are added, the solution is then cooled in an ice bath, and 0.19 ml (2.2 mmol) of oxalyl chloride in 2 ml of benzene are added dropwise. Stirring is continued for 15 min. at 0° C. and for 45 min. at room temperature, after which time gas evolution (HCl, CO, CO2) virtually ceases. Volatiles are evaporated in vacuo, and the residue is taken up in 2 ml of CH2Cl2. This solution is added dropwise with ice cooling to a solution of 0.47 ml(5 mmol) of tert.-butanol, 0.35 ml (2.5 mmol) of triethylamine, and 12.2 mg (0.1 mmol) of 4-dimethylaminopyridine in 3 ml of CH2Cl2. After stirring at 0° C. and room temperature for 20 min. each, the mixture is washed with aqueous KHSO4 solution, dried over MgSO4, evaporated, and filtered over silica gel to afford 410 mg (57%) of t-butyl methyl 2,4-dibromoglutarate. 1H NMR (CDCl3): δ4.52, 4.41, 4.40, 4.27 (each t, 1H, J=7.5), 3.81 (s, 3H), 1.49 (s,9H); dl isomer: δ2.61 (t, 2H, J=7.5); meso isomer: δ 2.83 (dt, 1H, J=7.5 (t), 15 (d)), 2.58 (dt, 1H, J=7.5 (t), 15 (d)); dl/meso=2:1. IR (neat): 2980, 1742, 1437, 1370, 1277, 1150, 843 cm-1.

Provenance & Evidence