| 100% |
at 190 - 200℃; for 2h; |
40 g of powder Zetaeta were washed with dilute hydrochloric acid once, H20 washed 3 times, washed once in methanol, acetone and once with 20 Mm Hg and 100 degrees Celsius for 10 minutes after drying, remove the nitrogen 25 g was added to 100 ml three Zetaeta Round-bottomed flask containing a catalytic amount of iodine was added 6 ml of anhydrous benzene was heated and stirred at reflux, was added over 45 minutes containing 8.35 grams, 0.05 mole of ethyl bromoacetate and 8.89 g XI, 0 06 mol triethylorthoformate XII. After the dropwise addition, the treated again take Zetaeta 6.25 g flour added to the system, after the reaction was refluxed for 6 hours, the reaction solution was transferred to a 100 ml ice-water and 50 g, excess acetic acid was added, the ether layer was separated, with washed with saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and concentrated under 1.5 mm Hg vacuum distillation, 79-81 ° C was collected as a colorless oil distillate 3, 3-ethoxy-propionate esters XIII2 8 g, yield 29.4percent; collected above to give the 2.8 g 3, 3-ethoxypropionate XIII at 190-200 degrees Celsius was heated under reflux for 2 hours with a delicate smell ., colorless liquid of ethyl acrylate, 3- XIV2 2 g, yield 100percent;. the 2.2 g, 152 mmol of ethyl acrylate, 3- XIV added to 7.5 ml of water and 7.5 ml two six ring oxygen mixed solvent, -10 degrees centigrade to cool large, slowly added 2.97 g after 16.72 mmol of NBS, the reaction 1 hour at room temperature, then 1.15 g, 15.2 mmol) was added thiourea after 1 hour at 80 ° C, ice-cooling, after addition of an excess of ammonia brown solid appeared, suction filtered to give a solid, after washing with water and drying give 1.4 g 2-aminothiazol-5-carboxylate XV of sitting Jie, The yield was 53.8percent |
| 62.1 g |
With potassium hydrogensulfate; at 100℃; for 5h;Inert atmosphere; Green chemistry; |
In a three-necked flask, 91 g (0.5 mol) of trichloroacetyl chloride was added, and 54 g (0.75 mol) of vinyl ether was slowly added dropwise, and the mixture was dropped for about 1.5 hours. The temperature was controlled at 30 ° C for 5 hours, and then steamed under 40 ° C. The low-boiling by-product is obtained; after steaming, 66 g (0.65 mol) of triethylamine and 100 g of ethanol are added, and the reaction is kept at 35 ° C for 5 h, filtered, and the cake is recovered. The filtrate is evaporated under reduced pressure at 50 ° C or less; Add 6.8 g (0.05 mol) of potassium hydrogen sulfate, raise the temperature to 100 ° C, pass nitrogen gas, the flow rate of nitrogen is 300 mL / min, keep the reaction for 5 h, the reaction is finished, and distilled under reduced pressure to obtain 62.1 g of ethyl 3-ethoxyacrylate. The rate was 86.1percent, and the purity by gas phase normalization was 98.8percent |
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