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ChemicalBook CAS DataBase List Arteether

Arteether synthesis

11synthesis methods
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Yield: 71.38%

Reaction Conditions:

Stage #1:orthoformic acid triethyl ester;dihydroartesiminin in ethanol at 20; for 0.25 h;
Stage #2: with acetyl chloride in ethanol at 10 - 15;
Stage #3: with sodium hydrogencarbonate in ethanol;water at 0 - 5; for 2 h;

Steps:

2
Dihydroartemisinin (25 g, 0.088 mole), ethanol (75 ml) and triethyl ortho formate (50 ml / 44.55 g = 0.301 mole) were stirred at ambient temperature for 15 minutes. The reaction mixture was cooled to 10-15°C and acetyl chloride (0.24 ml / 0.265 g =0.0034 mole) was added. Stirring was continued at 10-15°C for another 3hs or till the end of the reaction (monitoring by TLC). The reaction mixture was diluted with sodium bicarbonate solution (0.25g in 150 ml water). The reaction mass was then cooled to 0°C-5°C and stirred for 2 hours. The precipitated product was filtered and washed with ethanol: water (1 :1, 2 X 25 ml). The product was suck-dried and then recrystallised from ethanol: water (1:1) to get the title product as white crystalline solid. Yield: 19.6g, (71.38%); m.p.: 81°C-84°C; [α]D20: +155° to +157° (2% solution in dehydrated ethanol). HPLC purity > 99%1HNMR : δ 0.91 (doublet, 3H), δ 0.96 (doublet, 3H), δ 1.16-1.18 (triplet, 3H), δ 1.21-1.34 (multiplet, 3H), δ 1.44 (singlet, 3H), δ 1.47-1.62 (multiplet, 2H), δ 1.65-1.66 (multiplet, IH), δ 1.7-1.91 (multiplet, 3H), δ 2.01-2.06 (multiplet, IH), δ 2.32-2.38 (multiplet, IH), δ 2.62-2.64 (multiplet, IH), δ 3.43 & 3.86 (multiplet, 2H), δ 4.80 (doublet, IH), δ 5.41 (singlet, IH)

References:

CALYX CHEMICALS AND PHARMACEUTICALS LTD. WO2009/109989, 2009, A1 Location in patent:Page/Page column 10

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