Yield:622405-78-1 71%

Reaction Conditions:

with triethylamine in dichloromethane at 0 - 20;

Steps:

3

Example 3 Preparation of 1-(4,7,10,13-tetraoxatetradecan-1-oyloxy)pyrrolidine-2,5-dione 2,5,8,11-tetraoxatetradecan-14-oic acid (40 g, 169 mmol) (example 4) was dissolved in methylene chloride (200 mL), cooled to 0 to 5° C. and N,N'-dimethyl formamide (5 mL). Added slowly thionyl chloride (26.2 g, 220 mmol) was added by maintaining the temperature at 0 to 5° C. The reaction mixture was refluxed at 40 to 45° C. for 2 hours. The solvent was evaporated under vacuum and the syrup (acid chloride) obtained was dissolved in methylene chloride (40 mL). In a separate 500 ml 3-necked round bottom flask N-Hydroxy succinimide (13.6 g, 118 mmol) in methylene chloride (100 ml) was taken, the mass was cooled to 0 to 5° C. and triethylamine (22.2 g, 220 mmol) was added. Added slowly the acid chloride obtained above at 0 to 5° C. The temperature of the reaction mixture was brought to room temperature and stirred for 3 hours. The reaction completion was monitored by TLC (Thin layer chromatography). The mass was acidified to pH 4-5 and product was extracted to methylene chloride (100 ml×3). Combined organic layer was washed with 1.5 M HCl solution, water, followed by 10% sodium bicarbonate solution and saturated sodium chloride solution. The organic layer was dried over sodium sulphate and treated with neutral alumina (10% w.r.t [with respect to] starting material) and charcoal (10% w.r.t starting material) and filtered over celite. The filtrate was concentrated under vacuum to remove the solvent completely to obtain 1-(4,7,10,13-tetraoxatetradecan-1-oyloxy)pyrrolidine-2,5-dione (40 g, 71%).

References:

US2011/118480,2011,A1 Location in patent:Page/Page column 5