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【答案】应助回帖
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cdpxiaoniao: 金币+40, 翻译EPI+1, ★★★很有帮助, 谢谢 2016-07-17 10:06:27
Codeinone
(a) We introduced 40g 发烟盐酸 into 300 ml dry isopropyl ether, agitated and cooled to -15C. We introduced in the as-prepared solution of 50 g recrystallized thebaine and dissolved in 230 ml CH2Cl2. We allowed the temperature increase to 0C, and we keep the reaction during 3 h. We poured this solution into an agitated suspension of 94 g sodium bicarbonate in 300 ml water, and we adjusted the PH at 8 with diluted NaOH solution. We decanted the organic layer and we extracted the aqueous solution with 100 ml and then 50 ml CH2Cl2. We washed with water of the obtained extracts, and we dried them with the help of sodium sulfate. After filtration, we evaporated the solvent under vacuum by ensuring that the temperature of the bath not exceed 45C, and then we stirred the solid residue in 80 ml methanol. We obtained 26 g brute codeinode at about 90 %, F=180C, (产率=50%). By recritallization in ethyl acetate, we obtained a pure codeine F=185C, alphaD = -204C (ethanol); the reference indicates that F=185-186C, alphaD = -205C (14).
(b) We dissolved 140 g dry HBr in 600 ml di-n-butyl ether at -15C. Rapidly, we add into this solution, a solution of 124 g thebaine dissolved in 600 ml CH2Cl2 cooled at -10C. The temperature increase to 0C, we keep the reaction during 5 min, then we poured the reacted mixture into an aqueous suspension of ice finely pounded and sodium bicarbonate (154 g), and we isolated the codeinone in the manner similar to the above described. We get 93 g codeinone F=175C at about 90 % (产率=79%). A recrystallization give the pure codeine F=184C, alphaD = -202C (1% in ethanol). |
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