- Synthesis of pharmaceutical drugs from cardanol derived from cashew nut shell liquid
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Cardanol from cashew nut shell liquid extracted from cashew nut shells was successfully converted into various useful pharmaceutical drugs, such as norfenefrine, rac-phenylephrine, etilefrine and fenoprofene. 3-Vinylphenol, the key intermediate for the synthesis of these drugs, was synthesised from cardanol by ethenolysis to 3-non-8-enylphenol followed by isomerising ethenolysis. The metathesis reaction worked very well using DCM, but the greener solvent, 2-methyl tetrahydrofuran, also gave very similar results. Hydroxyamination of 3-vinylphenol with an iron porphyrin catalyst afforded norfenefrine in over 70% yield. Methylation and ethylation of norfenefrine afforded rac-phenylephrine and etilefrine respectively. A sequence of C-O coupling, isomerising metathesis and selective methoxycarbonylation afforded fenoprofene in good yield. A comparison of the routes described in this paper with some standard literature syntheses of 3-vinylphenol and of the drug molecules shows significant environmental advantages in terms of precursors, yields, number of steps, conditions and the use of catalysts. The Atom Economy of our processes is generally similar or significantly superior to those of the literature processes mainly because the side products produced during synthesis of 3-vinylphenol (1-octeme, 1,4-cyclohexadiene and propene) are easily separable and of commercial value, especially as they are bio-derived. The E Factor for the production of 2-vinylphenol by our process is also very low compared with those of previously reported syntheses.
- Shi, Yiping,Kamer, Paul C. J.,Cole-Hamilton, David J.
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supporting information
p. 1043 - 1053
(2019/03/12)
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- Method for synthesizing metaraminol bitartrate
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The invention provides a process for synthesizing metaraminol bitartrate. The process comprises the following steps: taking carbobenzoxy-L-alanine as a raw material, carrying out a cyclization reaction, and carrying out a reaction with a Grignard reagent so as to prepare an intermediate (4S)-N-carbobenzoxy-5-(3-(benzyloxy)phenyl)-5-hydroxy-4-methyloxazolane; carrying out a hydrolytic ring-opening reaction on the intermediate, and producing (2S)-2-(carbobenzoxy)amino-1-(3-benzyloxyphenyl)-1-acetone; carrying out a reduction reaction on the (2S)-2-(carbobenzoxy)amino-1-(3-benzyloxyphenyl)-1-acetone so as to obtain (1R,2S)-2-(carbobenzoxy)amino-1-(3-benzyloxyphenyl)-1-propanol; performing deprotection on the (1R,2S)-2-(carbobenzoxy)amino-1-(3-benzyloxyphenyl)-1-propanol so as to obtain metaraminol; finally, performing salt formation on metaraminol and L-tartaric acid, thereby obtaining the metaraminol bitartrate. According to the method disclosed by the invention, usage of an expensive catalyst and chiral resolution can be avoided, and the cost is greatly reduced; by utilizing chemical synthesis, industrial production of optical pure metaraminol bitartrate becomes possible.
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Paragraph 0019; 0022
(2017/11/18)
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- Enzymatic and Chemoenzymatic Three-Step Cascades for the Synthesis of Stereochemically Complementary Trisubstituted Tetrahydroisoquinolines
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Chemoenzymatic and enzymatic cascade reactions enable the synthesis of complex stereocomplementary 1,3,4-trisubstituted tetrahydroisoquinolines (THIQs) with three chiral centers in a step-efficient and selective manner without intermediate purification. The cascade employs inexpensive substrates (3-hydroxybenzaldehyde and pyruvate), and involves a carboligation step, a subsequent transamination, and finally a Pictet–Spengler reaction with a carbonyl cosubstrate. Appropriate selection of the carboligase and transaminase enzymes enabled the biocatalytic formation of (1R,2S)-metaraminol. Subsequent cyclization catalyzed either enzymatically by a norcoclaurine synthase or chemically by phosphate resulted in opposite stereoselectivities in the products at the C1 position, thus providing access to both orientations of the THIQ C1 substituent. This highlights the importance of selecting from both chemo- and biocatalysts for optimal results.
- Erdmann, Vanessa,Lichman, Benjamin R.,Zhao, Jianxiong,Simon, Robert C.,Kroutil, Wolfgang,Ward, John M.,Hailes, Helen C.,Rother, D?rte
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supporting information
p. 12503 - 12507
(2017/09/13)
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- Synthesis method of metaraminol bitartrate
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The invention discloses a synthesis method of metaraminol bitartrate, which comprises the following steps of: (1) additive reaction of nitroethane and hydroxybenzaldehyde, (2) additive reaction post-treatment and purification, (3) catalytic hydrogenation and (4) salification, wherein a catalysis system adopted by the additive reaction is copper acetate monohydrate, amine and chiral alkali; the amine in the catalysis system is N,N-diisopropylethylamine and/or triethylamine; the temperature and time of the additive reaction are 0-10 DEG C and 4-6h respectively; pH (potential of hydrogen) of a reaction system is adjusted to 6-7 by acetic acid in the additive reaction post-treatment and purification. On the one hand, N,N-diisopropylethylaine and the like are used to substitute imidazole to form the catalysis system with chiral alkali and copper acetate monohydrate, on the other hand, the pH of the system after the additive reaction is adjusted to 6-7, so that a higher-yield target product can be obtained.
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Paragraph 0017
(2017/07/19)
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- A heavy tartaric acid metaraminol synthetic method
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The invention discloses a synthesis method of metaraminol bitartrate, and in particular provides a method for synthesizing metaraminol bitartrate by using a chiral catalysis method. The synthesis method comprises the steps: catalyzing a chiral addition reaction of hydroxybenzaldehyde and nitroethane by using a chiral catalyst system consisting of cinchona alkaloid, copper acetate hydrate and less imidazole to obtain an addition product with a dominant required spatial configuration, and then reducing nitro by using hydrogen in the presence of Pd-C to obtain amine to obtain aramine, and salifying the aramine with L(+)-tartaric acid to obtain a final product metaraminol bitartrate. According to the synthesis method, an enzyme catalyst is prevented from being used, a raw material of the synthesis reaction is easily available, the chiral catalyst is easily purchased or prepared self, the synthesis steps are relatively less, the chiral control efficiency is higher, the enantioselectivity is high, the yield is good, the reaction operation is easily controlled, and is safe and reliable, and the foundation is laid for the later industrialized amplification production.
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Paragraph 0048; 0049
(2017/02/09)
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- ASSAYS FOR AMPHETAMINE AND METHAMPHETAMINE
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Methods, compositions and kits are disclosed. The compounds disclosed comprise an amphetamine moiety and a methamphetamine moiety linked together by a first linking group. A second linking group depends from the first linking group and comprises a functional group. The distance of the amphetamine moiety and the methamphetamine moiety from the point of linkage of the second linking group to the first linking group is approximately the same. The compounds may be linked to labels and used in assays for the detection of amphetamine and/or methamphetamine in samples suspected of containing these drugs.
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Page/Page column 41-42; 7/8
(2010/02/14)
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