- METHOD FOR SYNTHESIZING NOVEL COMPOUNDS DERIVED FROM 3-HYDROXY-CYCLOPENTYL ACETIC ACID
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The present invention relates to compounds of formula (I): in which R1 is a hydrogen atom, a phenyl radical, or a straight or branched, saturated or unsaturated hydrocarbon radical having 1 to 8 carbon atoms.
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Paragraph 0263; 0264; 0265; 0266
(2018/03/25)
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- Cyclic ketones, their preparation and their use in the synthesis of amino acids
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A method is provided for making an enantiomerically pure of the formula: in which R and R′ represent C1?C10 alkyl, C2?C10 alkenyl or C3?C10 cycloalkyl and the wedges signify (S)- or (R)-stereochemistry, the substituents in compound (II) being trans. Conjugate addition is carried out between an organometallic nucleophile that provides a group R as defined above and (R)-4-acetoxycyclopent-2-en-1-one, (S)-4-acetoxycyclopent-2-en-1-one or a similar compound in which acetoxy is replaced by another leaving group to give, e.g. in the case of the acetoxy compound, a trans 3,4-disubstituted addition product of formula III or IV; The acetyl group is eliminated from the addition product to give an (R)- or (S)-4-alkyl or 4-alkenyl cyclopent-2-en-1-one the compound of formula is then to be hydrogenated to give a cyclopentanone of formula (I) or conjugate addition of a second organometallic nucleophile that provides a group R′ as defined above to the compound of the above formula may be carried out to give a trans 3,4-disubstituted addition product of formula (II). One of the above compounds may be converted e.g. via an intermediate (XV)-(XVIII) (in which the substituents R and R′ and the wedges have the meanings indicated above) to a gabapentin analogue of one of the formulae shown below: in which the substituents R and R′ and the wedges also have the meanings indicated above.
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- A CONVENIENT METHOD FOR THE PRODUCTION OF 2-SUBSTITUTED 2-CYCLOPENTEN-1-ONES FROM ALKYL (ALKENYL) 2-CHLOROCYCLOPROPYL KETONES
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2-Substituted 2-cyclopenten-1-ones were obtained with good yields by the reaction of the respective 2-chlorocyclopropyl ketones with an aqueous solution of sodium hydroxide.
- Kulinkovich, O. G.,Sorokin, V. L.
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p. 196 - 197
(2007/10/02)
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- Synthesis of 2-Alkyl-2-cyclopenten-1-ones. A Versatile Kinetic Alkylation-Ozonolysis Procedure for the Preparation of γ-Ketoaldehydes
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A range of 2-alkyl-2-cyclopenten-1-ones including the prostaglandin precursor 2-(6-methoxycarbonylhexyl)-2-cyclopenten-1-one and the jasmonoid precursor 2--2-cyclopenten-1-one, have been prepared by a short synthetic route which begins with 6-methyl-5-hepten-2-one and generates the key 1,4-ketoaldehyde intermediates by a kinetic alkylation-ozonolysis procedure.
- Geraghty, Niall W. A.,Morris, Noreen M.
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p. 603 - 607
(2007/10/02)
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- A Regioselective Synthesis of Cyclopentenones from 4-Thianone
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Alkyl-substituted 3-cyclopentenones 4 and 5 were prepared in moderate to good yields starting from 4-thianone by the selective alkylation and Ramberg-Baecklund-type reactions.One route starts with 6-alkyl-1,4-dioxa-8-thiaspirodecane 8,8-dioxides (8) and another with 7-alkyl-1,4-dioxa-7-(p-tolylsulfonyl)-8-thiaspirodecane 8,8-dioxides (15), followed by acid-catalyzed cleavage of the 1,3-dioxolane ring of 1,4-dioxaspironon-7-enes 9 and 16 to afford 4 and 5.
- Matsuyama, Haruo,Miyazawa, Yasuyuki,Takei, Yuji,Kobayashi, Michio
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p. 1703 - 1710
(2007/10/02)
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- TETRAHYDROTHIOPYRAN-4-ONE. A USEFUL 5 C SYNTHON FOR THE SYNTHESIS OF 3-CYCLOPENTENONES
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2-Alkyl-3-cyclopentenones were prepared in moderate yields starting from tetrahydrothiopyran-4-one by the one-pot Ramberg-Baecklung reaction of 6-alkyl-1,4-dioxa-8-thiaspirodecane-8,8-dioxides, followed by acid catalyzed de-dioxolanation.
- Matsuyama, Haruo,Miyazawa, Yasuyuki,Takei, Yuji,Kobayashi, Michio
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p. 833 - 836
(2007/10/02)
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- FACILE SYNTHESIS OF 2-SUBSTITUTED CYCLOPENTENONES
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An efficient synthesis of 2-substituted cyclopentenones is reported.Key reactions are the cyclopropanation of 2,2-dimethyl-3(2H)-furanone and subsequent conversion to the title compounds by oxidative fragmentation.
- Baldwin, S. W.,Blomquist, H. R.
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p. 3883 - 3886
(2007/10/02)
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