Synthesis
To a solution of (3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid (5.0 g, 24.5 mmol) in THF (100 ML, 20.x.) was added TBTU (11.8 g, 1.5 equiv), N-methylmorpholine (NMM, 4.1 mL, 1.5 equiv) and the mixture was stirred at 20° C. for 30 min. Morpholine (3.2 mL, 1.5 equiv) was added, and the reaction mixture was stirred at 20° C. for an additional 6h. The solid was filtered off by filtration, and the cake was washed with THF (10 mL, 2.x. .x.2). The organic solution was concentrated under a vacuum. The residue was purified by silica gel column chromatography (hexanes: EtOAc, from 1:4 to 4: 1) to afford 4.3 g of the desired morpholine amide (((3AS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)(morpholino)methanone) as a white solid.
References
[1] Patent: US2009/30198, 2009, A1. Location in patent: Page/Page column 8
[2] Patent: US2010/16422, 2010, A1. Location in patent: Page/Page column 4
[3] Patent: EP2332947, 2011, A1. Location in patent: Page/Page column 6-7
[4] Patent: EP2661256, 2018, B1. Location in patent: Paragraph 0091
[5] Patent: CN106892948, 2017, A. Location in patent: Paragraph 0195; 0196; 0197; 0198
