- Preparation method of 5,5-dimethyl-3-methylene pyrrolidine-2-ketone
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The invention discloses a preparation method of 5,5-dimethyl-3-methylene pyrrolidine-2-ketone. The preparation method comprises the following steps: (S1) under the action of strong organic alkali, formaldehyde and a compound I generate condensation reaction to obtain a compound II; (S2) the compound II and a halogenating reagent generate halogenating reaction to obtain a compound III; (S3) under the action of the strong organic alkali, the compound III and 2-nitropropane generate substitution reaction to obtain a nitryl-containing compound IV; (S4) the compound IV carries out domino reaction of reducing nitryl and closing rings under the action of a catalyst and a reducing agent to obtain the 5,5-dimethyl-3-methylene pyrrolidine-2-ketone. The preparation method disclosed by the invention has the beneficial effects that the synthetic steps are fewer, the implementation is simple and easy, no harsh reaction condition is needed, the process route is novel, the yield is more than 50%, andthe reaction heat and gas generation is well controlled. The preparation method disclosed by the invention has the characteristics of novel process route, relatively mild reaction conditions, easy expansion, large-scale production and the like.
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- PRODUCTION OF MONATIN ENANTIOMERS
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Methods for the preparation of the high intensity sweetener, monatin, 3-(1-amino-1,3-dicarboxy-3-hydroxy-but-4-yl)indole, its salts and internal condensation products thereof, including methods applicable to the large-scale production of monatin are described.
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Page/Page column 7
(2009/04/24)
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- PROCESS FOR PREPARING L-NUCLEIC ACID DERIVATIVES AND INTERMEDIATES THEREOF
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A novel method has been found to produce 2,2′-anhydro-1-(β-L-arabinofuranosyl)thymine as a novel useful intermediate compound. A novel method has been further found to produce thymidine from 2,2′-anhydro-1-(β-L-arabinofuranosyl)thymine. According to these methods, synthesis of various L-nucleic acid derivatives, synthesis of which has been difficult till now, is possible.
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Page/Page column 4
(2009/01/24)
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- Practical preparation of 2-halomethyl-allyl carboxylates
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An improved, efficient preparation of 2-(halomethyl)allyl carboxylates starting from diethyl bis(hydroxymethyl) malonate and hydrobromic acid is reported. The allylic halogen of 2-(chloromethyl)acrylate and 2-(bromomethyl)acrylate are readily exchanged during esterification.
- Sun, Chong-Si,Cheng, Hsiu-Yi,Lin, Yu-Shiang,Hou, Duen-Ren
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p. 435 - 438
(2008/12/22)
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- L-NUCLEIC ACID DERIVATIVES AND PROCESSES FOR THE SYNTHESIS THEREOF
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A novel method has been found to produce 2,2'-anhydro-1-(β-L-arabinofuranosyl)thymine as a novel useful intermediate compound. A novel method has been further found to produce thymidine from 2,2'-anhydro-1-(β-L-arabinofuranosyl)thymine. A novel method has been further found to L-2'-deoxyribose derivatives as a useful synthetic intermediate through L-2,2'-anhydro-5,6-dihydrocyclouridine derivative. According to these methods, synthesis of various L-nucleic acid derivatives, synthesis of which has been difficult till now.
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Page/Page column 17-18
(2008/06/13)
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