Water → HCID 123277194, compound

A mixture of 4-amino-2-fluoro-N-methylbenzamide (1.68 g, 10 mmol), H2SO4 (0.68 mL) and water (13 mL) was gently heated until all components were completely dissolved. The mixture was cooled under stirring to 0-5° C., and NaNO2 (0.7 g, 10 mmol) dissolved in water (2 mL) was then added dropwise. The resulting mixture was stirred at 0-5° C. for 0.5 h and then slowly poured into a solution of KI (5 g) in cold water (20 mL). The solution was then heated up to 80° C. and stirred for 0.5 h. After cooling, it was treated with 30 mL of chloroform and filtered. The organic layer was washed with a 5% Na2SO3 solution, dried over Na2SO4, and rotovapped. Column chromatography on silica gel (hexane/EtOAc=6:1) afforded 2.33 g (83%) of 2-fluoro-4-iodo-N-methylbenzamide (4.1). MS (ESI) [M+H]+ 280. 1H NMR (400 MHz, DMSO-d6) δ 8.25 (m, 1H), 7.73 (d, J=10.0 Hz, 1H), 7.65 (d, J=7.8 Hz, 1H), 7.37 (t, J=7.8 Hz, 1H), 2.75 (d, J=4.4 Hz, 3H). A solution of compound 4.1 (9 g, 32 mmol) in DMF (25 mL) was added to an ice-cooled suspension of NaH (1.48 g, 36.8 mmol, 60% in oil, washed with hexane) dissolved in DMF (50 mL). The resulting mixture was vigorously stirred for 0.5 h in an ice bath, then SEM-chloride (6.46 g, 39 mmol) was added and the mixture was continuously stirred overnight at the ambient temperature. After the reaction was completed, the mixture was poured into water (400 mL) and the obtained product was extracted with benzene (2×200 mL), washed with water, dried over Na2SO4, and then filtered through a 3-cm layer of silica gel washing with 5:1 hexane/EtOAc. The solvent was evaporated in vacuum providing 11 g (84%) of 2-fluoro-4-iodo-N-methyl-N-[2-(trimethylsilyl)ethoxymethyl]benzamide (6.1). MS (ESI) [M+H]+ 520. 1H NMR (400 MHz, CDCl3) δ 7.58 (m, 1H), 7.52 (m, 1H), 7.12 (m, 1H), 5.01 (s, 0.8H), 4.58 (s, 1.2H), 3.63 (t, J=8.2 Hz, 0.8H), 3.31 (t, J=8.2 Hz, 1.2H), 3.14 (s, 1.8H), 2.92 (d, J=0.8 Hz, 1.2H), 0.99 (t, J=8.2 Hz, 0.8H), 0.82 (t, J=8.2 Hz, 1.2H), 0.04 (s, 3.6H), −0.01 (s, 5.4H). A mixture of 6.69 g (51 mmol) of amino acid (R)-4.2 or 9.55 g of (R)-4.3, 17.4 g (42.5 mmol) of 6.1, 1.62 g (8.5 mmol) of CuI, 23.5 g (0.17 mol) of K2CO3, 36 mL of water, 145 mL of DMF, and 3-5 drops of Et3N was stirred for 10 min, then 6.56 g (46.8 mmol) of 2-acetylcyclohexanone was added and the stirring continued at 100° C. for 24 h. After cooling, the mixture was rotovapped, the residue was treated with 200 mL of water and acidified with hydrochloric acid to pH 2-3 (˜30 mL). Then, 200 ml, of ether was added, the mixture was stirred for 0.5 h, and the resulting precipitate was filtered off, washed with 50 mL of ether, and dried in vacuum to give 10.7 g (65% from acid (R)-4.2) of (R)-3-(3-fluoro-4-{methyl[2-(trimethylsilyl)ethoxymethyl]carbamoyl}phenylamino)-tetrahydrofuran-3-carboxylic acid ((R)-6) (55% from ester (R)-4.3). MS (ESI) [M+H]+ 413. 1H NMR (400 MHz, DMSO-d6) δ 12.97 (brs, 1H), 7.07 (m, 2H), 6.31 (brs, 1H), 6.17 (brs, 1H), 4.85 (brs, 0.67H), 4.60 (brs, 1.33H), 4.10 (brs, 1H), 3.87 (brs, 3H), 3.51 (brs, 0.67H), 3.24 (brs, 1.33H), 2.93 (s, 2H), 2.86 (brs, 1H), 2.56 (brs, 1H), 2.16 (brs, 1H), 0.89 (brs, 0.67H), 0.73 (brs, 1.33H), 0.03 (m, 9H).

1. temperaturecooled
2. waitthe mixture was continuously stirred overnight at the ambient temperature
3. extractionthe obtained product was extracted with benzene (2×200 mL)
4. washwashed with water
5. dry with materialdried over Na2SO4
6. filtrationfiltered through a 3-cm layer of silica gel washing with 5:1 hexane/EtOAc
7. customThe solvent was evaporated in vacuum

ORD record

ord-332eda45644e437db211426814fe8e7b

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09073874B2