3401-28-3Relevant academic research and scientific papers
Entecavir intermediate and its preparation method
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Paragraph 0377-0383; 0391; 0392; 0393; 0394, (2017/12/28)
The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 8 comprises the following steps: performing hydroxyl protection group removal reaction on a compound 9 in a solvent under an acidic condition, so as to obtain the compound 8. A provided preparation method for an entecavir intermediate compound 9 comprises the following steps: performing hydroxyl protection group adding reaction on a compound 10 in an aprotic organic solvent under an alkali condition, so as to obtain the compound 9. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
A kind of preparation method of the midbody of entecavir, and intermediate
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Paragraph 0386; 0396; 0401; 0402, (2017/08/02)
The invention discloses Entecavir intermediates and a preparation method thereof. The preparation method of an Entecavir intermediate represented by a formula IV or IV' shown in descriptions comprises the following step of enabling a compound V to be subjected to amino protecting group and hydroxyl protecting group removal reaction in the presence of protonic acid in a solvent. The preparation method disclosed by the invention has the advantages that raw materials are cheap and are easily obtained, reaction conditions are mild, side reactions are few, the yield is high, the pollution to the environment is little, and the intermediates are easily purified and separated, so that the preparation method is applicable to industrial production.
Entecavir intermediate and its preparation method
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Paragraph 0380; 0385-0386; 0388; 0394, (2017/12/28)
The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 10 comprises the following steps: performing reducing reaction on an ester compound 11 in an organic solvent under the effect of a reducing agent, so as to obtain the compound 10. A provided preparation method for an entecavir intermediate compound 11 comprises the following steps: reacting a compound 12 with a hydroxyl protection reagent in an organic solvent in the presence of an acid to add a hydroxyl protection group, so as to obtain the compound 11. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
Entecavir intermediate and its preparation method
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Paragraph 0373; 0381; 0388-0389; 0391; 0395-0397, (2017/10/28)
The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 3 comprises the following steps: performing reducing reaction on a compound 4 in a solvent, so as to obtain the compound 3. A provided preparation method for an entecavir intermediate compound 4 comprises the following steps: performing transacetalation reaction on a compound 5 and a compound 18 in an organic solvent under an acid condition, so as to obtain the compound 4. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
A kind of preparation method of the midbody of entecavir, and intermediate
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Paragraph 0388; 0389; 0398, (2017/08/02)
The invention discloses Entecavir intermediates and a preparation method thereof. The preparation method of an Entecavir intermediate represented by a formula VIII shown in descriptions comprises the following step of enabling compounds IX and VIII' to be subjected to ring cleavage reaction in the presence of alkali in a non-aprotic organic solvent. The invention further discloses an Entecavir intermediate compound represented by a formula X or IX shown in descriptions. The preparation method disclosed by the invention has the advantages that raw materials are cheap and are easily obtained, the reaction conditions are mild, side reactions are few, the yield is high, the pollution to the environment is little, and the intermediates are easily purified and separated, so that the preparation method is applicable to industrial production.
Palladium-catalyzed desymmetrization of silacyclobutanes with alkynes: Enantioselective synthesis of silicon-stereogenic 1-sila-2-cyclohexenes and mechanistic considerations
Shintani, Ryo,Moriya, Kohei,Hayashi, Tamio
supporting information; experimental part, p. 2902 - 2905 (2012/07/17)
A palladium-catalyzed enantioselective desymmetrization of silacyclobutanes with alkynes has been developed to give silicon-stereogenic 1-sila-2-cyclohexenes with high enantioselectivity. The products thus obtained undergo further derivatizations with complete stereoselectivity, and a new catalytic cycle involving alkyne coordination (oxidative cyclization)- transmetalation (σ-bond metathesis)-reductive elimination has also been proposed.
SILAETHENE I. DARSTELLUNG UND CHARAKTERISIERUNG VON MONOSILACYCLOBUTANEN
Auner, N.,Grobe, J.
, p. 25 - 52 (2007/10/02)
Monosilacyclobutanes of the type RR' are prepared by ring closure reactions of 3-halopropylhalosilanes and by substitution of SiCl containing silacyclobutane rings with organometallic reagents (RMgX, LiR, NaCp).Under optimal experimental conditions yields between 50 and 95percent can be obtained by both procedures.Characterization of the compounds is accomplished by analytical (C, H, N) and NMR, IR and mass spectroscopic investigations.
