Potassium Carbonate → Methyl 5-chloro-2-ethynylbenzoate

To a solution of methyl 5-chloro-2-[2-(trimethylsilyl)ethynyl]benzoate (10 g, 37.5 mmol) in Methanol (150 ml) was added K2CO3 (10.36 g, 75 mmol) at room temperature and in air. The reaction mixture was stirred for 1 hour before being concentrated under reduced pressure. The residue was dissolved in deionized water (50 ml) and EtOAc (50 ml). The phases were separated and the aqueous layer was extracted with EtOAc (2×50 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by FCC (50 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 9:1 Heptane:EtOAc) to give 5.75 g (55.2%) of methyl 5-chloro-2-ethynylbenzoate as an orange oil that solidified upon standing. This material contained 30% of ethyl ester which was suitable for use without any further purification. LC-MS 38%, 1.98 min (3 minute LC-MS method), m/z=195.0/196.9, 1H NMR (500 MHz, Chloroform-d) δ ppm 7.93 (d, J=2.2 Hz, 1H), 7.55 (d, J=8.3 Hz, 1H), 7.45 (dd, J=8.3, 2.3 Hz, 1H), 3.94 (s, 3H), 3.43 (s, 1H).

1. concentrationbefore being concentrated under reduced pressure
2. dissolutionThe residue was dissolved in deionized water (50 ml)
3. customThe phases were separated
4. extractionthe aqueous layer was extracted with EtOAc (2×50 ml)
5. dry with materialThe combined organic extracts were dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by FCC (50 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 9:1 Heptane:EtOAc)

ORD record

ord-0367de1a19f6469f843263c4033c734d

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08410088B2