Synthesis
The general procedure for the synthesis of 5-bromo-2-methylisodihydroindol-1-one from methyl 4-bromo-2-(bromomethyl)benzoate (1.2 g, 3.0 mmol) and methylamine (2.0 M THF solution, 10 mL, 20 mmol) is as follows:
1. add a THF solution of methyl 4-bromo-2-(bromomethyl)benzoate and methylamine to the reaction tube.
2. the reaction tube was sealed, the mixture was stirred and heated at 50 °C overnight.
3. Upon completion of the reaction, the mixture was cooled to room temperature.
4. The reaction mixture was filtered and the precipitate was washed with THF.
5. The filtrate was concentrated under vacuum to give the crude product.
6. The crude product was purified by column chromatography using 0-100% ethyl acetate/heptane as eluent to afford 5-bromo-2-methylisodihydroindol-1-one (623 mg, 2.75 mmol, 71% yield) as a white solid.
The product characterization data are as follows:
1H NMR (CDCl3, 400MHz) δ/ppm: 7.73-7.68 (1H, m), 7.64-7.56 (2H, m), 4.36 (2H, s), 3.19 (3H, s).
MS Method 3: RT: 3.18min, m/z 226.0/228.0 [M + H]+.
References
[1] Patent: WO2016/51193, 2016, A1. Location in patent: Paragraph 00527; 00530; 00531
[2] Patent: US10112955, 2018, B2. Location in patent: Page/Page column 29
[3] Patent: WO2013/148603, 2013, A1. Location in patent: Paragraph 0233-0234
[4] Patent: EP3406612, 2018, A1. Location in patent: Paragraph 0086; 0087
