A kind of cleaning preparation method of 4-hydroxymethylthiazole and intermediate thereof
A technology of tetramethylpiperidine and alkyl, which is applied in the field of clean preparation of 4-hydroxymethylthiazole, can solve problems such as skin burns and dermatitis, irritating lachrymatory, strong irritation, etc., and achieves less side effects , The reaction is simple and easy to operate, and the effect of reducing production costs
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Embodiment 1
[0072] The preparation of embodiment 1 acetate-3-chloro-2-hydroxyl propyl ester (compound IV)
[0073] In a 250mL three-necked flask, add epichlorohydrin (4.6g, 49.7mmol) and acetonitrile (50mL), then add acetic acid (3.9g, 64.9mmol) and tetrabutylammonium bromide (161mg, 0.5mmol), the system Heat to reflux. After the reaction was detected by TLC, the solvent was evaporated under reduced pressure, and the crude product was added to 50 mL of 5% potassium carbonate aqueous solution, and then added to 60 mL of ethyl acetate for extraction. After the organic phase was concentrated, the product was distilled under reduced pressure to obtain 6.1 g of a colorless liquid with a yield of 80.4% and a purity of 98.2% by HPLC. 1 H NMR (CDCl 3 ): δ4.22(d, J=8.0Hz, 2H), 4.10-4.06(m, 1H), 3.69-3.59(m, 2H), 2.78(d, J=8.0Hz, 1H), 2.12(s, 3H).
Embodiment 2
[0074] The preparation of embodiment 2 acetic acid-3-chloro-2-carbonyl propyl ester (compound III)
[0075] In a 250mL three-necked flask, add acetic acid-3-chloro-2-hydroxypropyl ester (5.0g, 32.8mmol), TEMPO (180mg, 1.2mmol), sodium bicarbonate (7.6g, 90.5mmol), ethyl acetate 50mL and water 20mL, the system was cooled to 4°C, and an aqueous solution (10mL) of sodium hypochlorite (3.6g, 48.3mmol) was added dropwise. After the dropwise addition, keep the system temperature and continue to stir for about half an hour, then add 20 mL of 5% sodium thiosulfate aqueous solution. Then the organic phase was separated, dried with anhydrous sodium sulfate, and the crude product was concentrated and distilled under reduced pressure to obtain 4.1 g of a colorless oily product with a yield of 83.0% and a purity of 99.2% by HPLC. 1 H NMR (CDCl 3 ), δ4.87(s,2H), 4.13(s,2H), 2.17(s,3H).
Embodiment 3
[0076] The preparation of embodiment 3 phenylacetic acid-3-bromo-2-carbonyl propyl ester (compound III)
[0077] In a 100mL three-necked flask, add phenylacetic acid-3-bromo-2-hydroxypropyl ester (5.0g, 18.3mmol), TEMPO (157.6mg, 0.9mmol), sodium bicarbonate (4.6g, 54.8mmol), bromide Potassium (3.4g, 28.6mmol), ethyl acetate 25mL and water 10mL, the system was cooled to 4°C, and sodium hypochlorite (2.1g, 28.2mmol) aqueous solution (5mL) was added dropwise. After the dropwise addition, keep the system temperature and continue to stir for about half an hour, then add 10 mL of 5% sodium thiosulfate aqueous solution. Then the organic phase was separated, dried with anhydrous sodium sulfate, and the crude product was concentrated and distilled under reduced pressure to obtain 4.7 g of a colorless oily product with a yield of 94.7% and an HPLC purity of 99.1%.
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