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Method for synthesizing p-menthane-3,9-diol
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A synthesis method and a menthane technology, applied in the field of organic chemical synthesis, can solve problems such as high requirements for equipment and personnel protection, cumbersome process, cumbersome reaction, etc., and achieve the effects of high yield, simplified operation process, and simplified preparation process
Active Publication Date: 2014-04-16
CHINA TOBACCO HUNAN INDAL CORP
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[0004] The disadvantages of the first method are: complicated process and high cost: hydroboration requires anhydrous and oxygen-free conditions to prepare diborane on the spot through the complex reaction of sodium borohydride and boron trifluoride ether, which requires equipment and The protection requirement of personnel is high, and reagent is expensive (Casanovas, J., Namba, A M., et al., J.Org.Chem.2001, 66, 3775-3782; Schmid, G., Hofheinz, W., J. Am.Chem.Soc., 1983,105:624-625); 3-alcohol hydroxyl needs protection and deprotection
The disadvantage of the second method is: epoxidation of isopulegol, catalyzed ring isomerization of methyl epoxy to allyl alcohol with lithium ethylenediamine under anhydrous conditions, and then catalytic hydrogenation of carbon-carbon double bonds to obtain the target product, A total of three-step reactions are required, and the reaction formula is as follows (schemel) (Schulte-Elte, K H., Ohloff, G., Helv. Chim. Acta, 1961, 50 (21): 153-165)
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Embodiment 1
[0020] In a 100 mL autoclave, add 1.0 g (5.9 mmol) of 8,9-epoxyisopulegol and 2 mL of methanol, add 0.3 g of Raney nickel, and feed 48 atm of hydrogen. The reaction was stirred at 60° C. for 5 hours. After the reaction was completed, the reaction liquid was poured out carefully. After filtration, concentration and column chromatography, the yield of p-menthane-3,9-diol was 64%. The spectral data of p-menthane-3,9-diol are: 1 H NMR: δ0.81-1.06(m, 2H), 0.92(d, J=6.8Hz, 3H), 0.96(d, J=7.2Hz, 3H), 1.16-1.28(m, 1H), 1.31-1.45 (m, 2H), 1.54-1.65 (m, 2H), 1.84 (s, 1H), 1.94-1.97 (m, 1H), 3.43 (dt, J=4.4, J=10.2, 1H), 3.55-3.65 ( m, 2H), 3.95 (s, br, 2H). MS m / z (100%): 172 (m + , 2), 81(100).
Embodiment 2
[0022] In a 100 mL autoclave, add 1.0 g (5.9 mmol) of 8,9-epoxyisopulegol and 3 mL of ethanol, add 0.3 g of Raney nickel, and feed 48 atm of hydrogen. The reaction was stirred at 60° C. for 5 hours. After the reaction was completed, the reaction liquid was poured out carefully. After filtration, concentration and column chromatography, the yield of p-menthane-3,9-diol was 66%. The spectral data of p-menthane-3,9-diol are the same as in Example 1.
Embodiment 3
[0024] In the 100mL autoclave, add 1.0g (5.9mmol) 8,9-epoxyisopulegol and 4mL of methanol and water (volume ratio is 1 / 1) mixed solvent, add Raney nickel 0.3g, pass into 80atm hydrogen. The reaction was stirred at 150° C. for 3 hours, and the reaction was completed. The aftertreatment was the same as in Example 1, and the yield of p-menthane-3,9-diol was 73%. The spectral data of p-menthane-3,9-diol are the same as in Example 1.
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Abstract
The invention discloses a method for synthesizing p-menthane-3,9-diol[2-(1-methyl-2-hydroxyl)ethyl-5-methylcyclohexan-1-ol]. The method comprises the following steps of: performing epoxidation reaction on isopulegol serving as a raw material to obtain 8,9-epoxy isopulegol, and performing selective reduction on the 8,9-epoxy isopulegol by a raney nickel catalytic hydrogenation method to obtain p-menthane-3,9-diol. The invention has the advantages that: the synthesis process is simple, reaction conditions are mild, and the method is easy and convenient to operate, environment-friendly and suitable for industrially producing the p-menthane-3,9-diol on a large scale.
Description
technical field [0001] The invention belongs to the technical field of organic chemical synthesis, and in particular relates to a method for synthesizing p-menthane-3,9-diol [2-(1-methyl-2-hydroxy)ethyl-5-methanol with isopulegol as a raw material. Cyclohexan-1-ol] method. Background technique [0002] P-menthane-3,9-diol has special aroma and cool feeling, it can be used as a useful intermediate in organic synthesis, such as for the preparation of dihydromenthalide. [0003] From isopulegol to synthesize p-menthane-3, the synthetic method of 9-diol is divided into two kinds: (1) take isopulegol as raw material, after the 3-hydroxyl is protected, by hydroboration-oxidation reaction, deprotection , make p-menthane-3,9-diol; (2) take isopulegol as raw material, available peroxide epoxidation synthesis 8,9-epoxy isopulegol (Waddell T.G., Ross P.A.J.Org .Chem., 1987,52:4802-4804; Schulte-Elte, K H., Ohloff, G., Helv.Chim.Acta, 1961,50(21):153-165.), then diisopropyl Catalyzed...
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