- New synthesis of polyfluoroalkyl racemic α-amino acids
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We describe here a new synthesis of racemic α-amino acids containing polyfluorinated aliphatic long chain RF(CH2)3Y (RF = C2F5, C6F13, C 8F17) (Y = CH(NH2)COOH) based on So?rensen's method. The radical addition of perfluoroalkyl iodides R FI (RF = C2F5, C6F 13, C8F17) at room temperature to ethyl-2-carbetoxy-2-phthalimido-pent-4-enoate 3 was first initiated by Et 3B/O2. Then, the reduction of adducts 4a-c using Et 3B/O2/Bu3SnH leads to ethyl-2-carbetoxy-2- phthalimido-5-perfluoroalkyl-pentanoate 5a-c under mild conditions. Experimental conditions for optimisation of the iodoperfluoroalkylation step using Et 3B/O2 were studied. Finally, deprotection of 5a-c gave the desired products 6a-c in good yields.
- Delon,Laurent,Blancou
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- Synthesis method of ticagrelor intermediate
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The invention provides a synthesis method of a ticagrelor intermediate 1. By selecting a more stable amino protecting group, the formation of by-products in the cyclization step is favorably controlled, the reaction conditions in each step are mild, the conversion rate is higher, the cost is effectively reduced, and the method is suitable for industrial production.
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Paragraph 0044-0046
(2020/06/16)
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- Synthesis of Carboranyl Phenylalanine for Potential Use in Neutron Capture Therapy of Melanoma
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A phenylalanine derivative incorporating the 1,2-dicarba-closo-dodecaborane (12) cage has been synthesised by the alkylation of diethyl formamidomalonate with benzyl bromide in the presence of sodium ethoxide followed by the removal of the protecting groups by hydrolysis and decarboxylation.The closo-carborane species was converted into the anionic nido-form to produce a more water-soluble form of the compound.
- Prashar, Jognandan K.,Moore, Douglas E.
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p. 1051 - 1054
(2007/10/02)
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- The biosynthesis of the streptolidine moiety in streptothricin F
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A series of arginines specifically labeled either with 13C and 15N or with 2H were synthesized and fed to Streptomyces L-1689-23. The streptothricin F isolated in each case was analyzed by either 13C or 2H NMR, respectively, in order to determine the labeling pattern obtained. From these results, it appears that arginine is metabolized to a β-ketoarginine, possibly via a pyridoxal phosphate adduct, and then via cyclization, reduction, rearrangement, and hydroxylation to the streptolidine moiety. The pathway described can also account for the formation of other known antibiotics, and for β-hydroxy-γ-amino acids, generally.
- Martinkus,Tann,Gould
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p. 3493 - 3505
(2007/10/02)
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