869-09-0

3479-80-9

31358-13-1

The general procedure for the synthesis of dimethyl cis-azetidine-2,4-dicarboxylate (CAS:31358-13-1) from 2,4-dibromopentanedioic acid is as follows: Example 3: Preparation of dimethyl cis-azetidine-2,4-dicarboxylate 1. 1.14 g (3.93 mmol) of 2,4-dibromopentanedioic acid, 1 mL of methanol, 1.2 mL of carbon tetrachloride (CCl4), and 1 drop of concentrated hydrochloric acid were mixed. 2. The reaction mixture was refluxed in the presence of sulfuric acid for 8 hours. 3. Upon completion of the reaction, an aqueous post-treatment is performed: extraction with dichloromethane (CH2Cl2) and saturated sodium bicarbonate (NaHCO3) solution. 4. The organic phase was filtered through a silica gel column and the solvent was evaporated to give 0.87 g (70% yield) of dimethyl 2,4-dibromoglutarate. Product characterization data: 1H NMR (CDCl3): δ 3.82 (s, 6H); dl-isomer: δ 4.53 (dd, 2H, J = 6.5, 8 Hz), 2.68 (dd, 2H, J = 6.5, 8 Hz); endo isomer: δ 4.41 (t, 2H, J = 7.5 Hz), 2.89 (dt, 1H, J = 7.5 (t), 14.5 (d Hz), 2.64 (dt, 1H, J = 7.5(t), 14.5(d)Hz); dl/meso = 3:1. IR (neat, cm-1): 3004, 2955, 1740, 1437, 1300, 1267, 1215, 1156, 851.