Synthesis
General procedure for the synthesis of α-bromo-γ-butyrolactone from γ-butyrolactone (bromination step): in a 1000 mL reaction vessel equipped with a stirring device, refluxing device, thermometer, dropping funnel, and nitrogen introduction tube, 200 g (2.32 mol) of γ-butyrolactone and 2.76 g (0.086 mol based on 3.7 mol% of γ-butyrolactone) of sulfur were added as the catalyst. 431 g (2.70 mol) of bromine was loaded into a dropping funnel. Stirring was initiated, the reaction temperature was controlled not to exceed 40 °C, and the bromine was slowly added dropwise. After the dropwise addition was completed, the reaction temperature was raised to about 90 °C and the reaction was maintained at this temperature for 1 hour. Subsequently, the temperature was raised to about 110°C and the reaction was continued for 3 hours.
References
[1] Patent: JP5837752, 2015, B2. Location in patent: Paragraph 0052; 0079-0081; 0082; 0085; 0086; 0088
[2] Journal of Porphyrins and Phthalocyanines, 2010, vol. 14, # 1, p. 89 - 100
[3] Bioorganic and Medicinal Chemistry Letters, 2011, vol. 21, # 10, p. 3074 - 3077
[4] Synlett, 2005, # 17, p. 2648 - 2652
[5] Organic Letters, 2011, vol. 13, # 14, p. 3670 - 3673
