Synthetic method of difluoromethyl substituted oxane-2-one
A synthesis method and technology of difluoromethyl, applied in the direction of organic chemistry, etc., can solve the problems of unstable volatility of compound 2, difficult to control, and long reaction period, and achieve the increase of atom economy, convenient monitoring of central control, shortening Synthesis Cycle Effects
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[0022] Raw material preparation
[0023] 1. Preparation of (S)-2-oxo-3-trityloxazolidine-4-carbaldehyde
[0024] The preparation of step (1), N-trityl-L-serine methyl ester
[0025] Disperse L-serine methyl ester hydrochloride (300g, 1.93mol) in dichloromethane (2.5L), add triethylamine (391g, 3.86mol), control the internal temperature between 0 and 10°C, and add three Dichloromethane solution (1.5L) of phenylchloromethane (541g, 1.93mol) was added dropwise and then raised to room temperature to react overnight. Slowly pour the reaction solution into saturated brine (2L), stir and separate the layers, separate the organic phase, add DCM (2×1L) to the aqueous phase for extraction, combine the organic phases and wash with saturated sodium chloride (2L). Dry over sodium sulfate, concentrate, and suck to dryness to obtain white solid N-trityl-L-serine methyl ester (590 g, yield 84.5%).
[0026] Step (2), the preparation of (S)-2-oxo-3-trityl oxazolidine-4-carboxylic acid methyl...
Embodiment 1
[0036] Step (1): Preparation of (S)-4-(difluoromethyl)-3-trityloxazolidin-2-one
[0037]
[0038] At room temperature, (S)-2-oxo-3-tritylazolidine-4-carbaldehyde (500g, 1.27mol) was dissolved in DCM (10L), and under the protection of an inert gas, the reaction solution was cooled and controlled The reaction temperature does not exceed 10°C, slowly inject DAST (253ml, 1.9mol), after the addition is complete, rise to 30-35°C for reaction, and monitor the reaction by color development of phosphomolybdic acid on a silica gel plate. After the reaction was completed, the reaction solution was slowly poured into ice-saturated aqueous sodium bicarbonate solution (8L), the drop rate was controlled, and the internal temperature was controlled to be less than 40°C. After the quenching was complete, the mixture was stirred and layered, and dichloromethane (3L× 3) Extraction, combined organic phases, washed with saturated sodium chloride (2.5×2L), dried over anhydrous sodium sulfate, co...
Embodiment 2
[0043] Step (1): Preparation of (R)-4-(difluoromethyl)-3-trityloxazolidin-2-one
[0044]
[0045] At room temperature, (R)-2-oxo-3-tritylazolidine-4-carbaldehyde (2g, 5.59mmol) was dissolved in toluene (20ml), under the protection of an inert gas, the reaction liquid was cooled, controlled The reaction temperature did not exceed 10°C, and BAST (2.5ml, 13.98mmol) was slowly injected. After the addition, it was raised to 35°C for reaction, and the reaction was monitored by phosphomolybdic acid color development on a silica gel plate. After the reaction was completed, a white solid (R)-4-(difluoromethyl)-3-trityloxazolidin-2-one (1.91g, yield 90% , ESI / MS: m / z=381 (M+H) + ).
[0046] Step (2): Preparation of (R)-4-(difluoromethyl)oxazolidin-2-one
[0047]
[0048] At room temperature, (R)-4-(difluoromethyl)-3-trityloxazolidin-2-one (1.9g, 5.00mmol) was dissolved in dichloromethane (20ml), and hydrochloric acid was added Gas, continue to stir until the reaction is comple...
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