Description
1-(2-hydroxymethyl)-1-H-pyrrole-2,5-dione is a synthetic building block for adding an maleimide group with a hydroxyl handle. The hydroxyl group enables further derivatization or replacement with other reactive functional groups.
Synthesis
General procedure for the synthesis of N-(2-hydroxyethyl)maleimide (HEMI) from 3a,4,7,7a-tetrahydro-2-(2'-hydroxyethyl)-4,7-epoxy-1H-isoindole-1,3(2H)-dione (HEMI-A): 0.19 mol (40 g) of HEMI-A was mixed with 227 g of xylene and 0.005 g of methylhydroquinone ( MEHQ, as antioxidant) was mixed. The reaction was heated under nitrogen protection at reflux at 130 °C for 3 h and 15 min to convert HEMI-A to HEMI with a conversion of 98.7% and a reaction yield of about 98.7%. After completion of the reaction, the reactor was cooled to room temperature, the reaction mixture was filtered and the solid product was washed with 15 g of xylene. The washed solid was dried under vacuum to give 25.1 g of HEMI in 93% yield based on HEMI-A. The purity of HEMI was confirmed to be greater than 99% by 1H-NMR analysis. The mother liquor and wash liquor were combined and the total mass was determined to be 230.2 g, which contained 1.17 g of HEMI, which can be recovered or recycled as described above.
References
[1] Patent: WO2007/44169, 2007, A1. Location in patent: Page/Page column 10
[2] Dyes and Pigments, 2017, vol. 145, p. 518 - 527
[3] Organic Letters, 2011, vol. 13, # 16, p. 4364 - 4367
[4] Advanced Functional Materials, 2014, vol. 24, # 33, p. 5261 - 5268,8
[5] Journal of Controlled Release, 2018, vol. 285, p. 187 - 199
