- 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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p. 1043 - 1053
(2019/03/12)
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- A feasibility study on the synthesis of phenylephrine via ruthenium-catalyzed homogeneous asymmetric hydrogenation
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We report a feasibility study on a new route to (R)-phenylephrine, based on the ruthenium-catalyzed asymmetric hydrogenation of an aminoketone precursor. The direct and fast asymmetric reduction of aminoketones or their hydrochloride salts is achievable at low catalyst loadings (molar substrate to catalyst ratio, S/C, >25,000/1, TOF up to 25,000 h-1) with high enantioselectivity (>95% ee), without the need for N-protection nor isolation of the free base prior to reaction.
- McGarrity, John F.,Zanotti-Gerosa, Antonio
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experimental part
p. 2479 - 2486
(2011/02/22)
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- SUBSTITUTED PHENETHYLAMINES
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Disclosed herein are substituted phenethylamine alpha adrenergic receptor modulators of Formula I, process of preparation thereof, pharmaceutical compositions thereof, and methods of use thereof.
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Page/Page column 30
(2009/01/20)
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