Method for synthesizing chloramphenicol
A synthesis method and technology of chloramphenicol, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of production cost, increase of three wastes, and long synthesis route of chloramphenicol, and achieve cheap raw materials, Raw materials are easily available and the total yield is high
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Embodiment 1
[0031] 1 of the preparation of embodiment 1 (R)-2-nitro-1-phenylethanol
[0032] 0.9 g of copper trifluoromethanesulfonate Cu(OTf)2 (0.25 mmol), 1.2 g of ligand {2,6-bis[(S)-4-isopropyl-1-phenyl-4,5-bis Hydrogen-1H-2-imidazolyl]pyridine} (2.6mmol) and 20ml of 1,4-dioxane were added to a 100ml single-necked flask, and the nitrogen flow was kept constant after replacing the air inside with nitrogen. After magnetic stirring for 2 hours, Cool in an ice bath, add 2.7 grams of benzaldehyde (25mmol), 15 grams of nitromethane (250mmol) and N-methylmorpholine (0.27 milliliters, 2.5mmol) successively, and the reaction solution was stirred in an ice bath for 24 hours. After the chromatographic detection of no raw material benzaldehyde spots, then the volatile solvent was removed by distillation under reduced pressure, the catalyst was removed by silica gel filtration, and the filtrate was concentrated to obtain 4.3 grams of product, with a yield of 97%, and the e.e value was 97% as deter...
Embodiment 2
[0033] The 2 of the preparation method of embodiment 2 (R)-2-nitro-1-phenylethanol
[0034] In a 100 ml single-necked flask, add 0.5 g of 1-[2-(4S)-4-R-4,5-dihydro-2-oxazoline-ethyl]piperidine, 0.09 g of trifluoromethanesulfonate For copper (CuOTf), replace the air inside with nitrogen and keep the nitrogen flow constant. After 3 hours of magnetic stirring, cool in an ice bath, add 2.7 g of benzaldehyde (2 mol) and 15 g of nitromethane (6 mol) to anhydrous di A mixture was formed in methyl sulfoxide, and then the reaction solution was stirred in an ice bath for 12 hours. After thin-plate chromatography detected no raw material benzaldehyde spots, the volatile solvent was removed by distillation under reduced pressure, the catalyst was removed by silica gel filtration, and the filtrate was concentrated to obtain The product was 4.2 grams, the yield was 92%, and the e.e value determined by HPLC was 97%.
Embodiment 3
[0035] Example 3 Preparation of (1R, 2R)-2-nitro-1-phenyl-1,3-propanediol 1
[0036] Add 20 ml of 1,4-dioxane into a 100 ml single-necked flask, replace the air inside with nitrogen and keep the nitrogen flow constant, stir magnetically and add 0.75 g of paraformaldehyde (25 mmol), 4.2 g of (R)-2 -Nitro-1-phenylethanol (25mmol) and N-methylmorpholine (0.27 ml, 2.5mmol), the reaction solution was stirred in an ice bath for 24 hours, no raw material (R)-2- was detected by thin plate chromatography After the nitro-1-phenylethanol spots, then the volatile solvent was removed by distillation under reduced pressure, purified by silica gel filtration, and the filtrate was concentrated to obtain 4.2 grams of product, with a yield of 85%, 1H NMR (acetone-d6) δ: 3.46 (ddd, J=3.2, 7.9, 12.0Hz, 1H), 3.70(s, 1H), 3.90(ddd, J=6.5, 9.2, 12.0Hz, 1H), 4.19~4.23(m, 2H), 4.84(ddd, J= 3.2, 9.2, 9.2Hz, 1H), 5.08 (d, J = 9.2Hz, 1H), 5.03~5.11 (m, 1H), 7.31~7.48 (m, 5H). 13C NMR (acetone-d6) δ: 61...
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