Carbon Dioxide → HCID 20071293, compound

544 mg (2 mmol) of 2,4-dibromoglutaric anhydride, 0.5ml 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), I5 (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.

1. temperaturethe solution is then cooled in an ice bath
2. customVolatiles are evaporated in vacuo
3. stirringAfter stirring at 0° C. and room temperature for 20 min. each, the mixture
4. washis washed with aqueous KHSO4 solution
5. dry with materialdried over MgSO4
6. customevaporated
7. filtrationfiltered over silica gel

ORD record

ord-ac889f28bdb64561b703fbd14aa85973

Source dataset

uspto-grants-1990_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04946839