- Development of an efficient process for 3,6-dihydro-2h-pyran-4-boronic acid pinacol ester
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An efficient process for the synthesis of 3,6-dihydro-2H-pyran-4-boronic acid pinacol ester has been developed in one-pot manner. Starting from the condensation of 4-tetrahydropyranone with hydrazine hydrate, the subsequent treatment of hydrazone with copper(II) bromide-triethylamine and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) conveniently gave 4-bromo-3,6-dihydro-2H-pyran, which was then conducted through palladium-catalyzed borylation to afford the desired product using a low loading of a Pd catalyst.
- Xue, Feng,Zhu, Yong,Li, Chang-Gong
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- Nickel-Catalyzed Conversion of Enol Triflates into Alkenyl Halides
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A Ni-catalyzed halogenation of enol triflates was developed and it enables the synthesis of a broad range of alkenyl iodides, bromides, and chlorides under mild reaction conditions. The reaction utilizes inexpensive, bench-stable Ni(OAc)2?4 H2O as a precatalyst and proceeds at room temperature in the presence of sub-stoichiometric Zn and either 1,5-cyclooctadiene or 4-(N,N-dimethylamino)pyridine.
- Hofstra, Julie L.,Poremba, Kelsey E.,Shimozono, Alex M.,Reisman, Sarah E.
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supporting information
p. 14901 - 14905
(2019/11/11)
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- Preparation method of heteroatom-containing cyclohexene halide
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The invention discloses a preparation method of a heteroatom-containing cyclohexene halide, belonging to the field of synthesis of fine chemical intermediates. According to the preparation method, cyclohexanone containing heteroatoms is used as a raw material, and gem-dihalide or alkenyl halide is mainly generated in a halogenating reagent; and after an additive is added into organic alkali, and hydrogen halide is removed to generate cyclohexene halide containing heteroatoms. The method is simple in process; the operation of purifying a mixture in traditional methods is avoided; and a productis fully utilized. Under close-to-elimination condition of gem-dibromide, an additive is added to overcome the problem of difficulties in gem-dichloride elimination is by adding, and the purpose of controlling regioselectivity is achieved through steric hindrance of different alkalis.
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Paragraph 0039-0041
(2019/12/25)
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- A 3,6-dihydro -2H-pyran-4-boronic acid frequency method for the synthesis of ester
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The invention discloses a synthetic method of 3,6-dihydro-2H-pyran-4-boronic acid pinacol ester, which comprises the following steps: 1) carrying out a reaction of tetrahydro-4H-pyran-4-one and hydrazine hydrate in a solvent to generate single ketone hydrazone; 2) carrying out a reaction of the single ketone hydrazone and copper bromide in a solvent in the presence of triethylamine to obtain a dibromo intermediate; 3) carrying out an elimination reaction of the dibromo intermediate and an alkali in a solvent to obtain an alkenyl bromide compound; 4) carrying out a Suzuki-Miyaura reaction of the alkenyl bromide compound and bis(pinacolato)diboron in a solvent in the presence of a palladium complex to obtain the product. The synthetic method of the invention is simple, and low in cost, adopts no dangerous raw materials, and is safe and suitable for large-scale production.
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Paragraph 0052-0054
(2017/03/25)
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- Method for synthesizing 3, 6-dihydro-2H-pyrazine (thiazine) furan-4-boric acid ester
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The invention discloses a method for synthesizing 3, 6-dihydro-2H-pyrazine (thiazine) furan-4-boric acid ester. According to the method, tetrahydropyrazole (thiazine) furan-4-ketone serves as the raw material, generates hydrazone with p-toluenesulfonhydrazide, then reacts with NBS/organic alkali to generate alkenyl bromide and next forms Grignard reagent with magnesium metal, after the Grignard reagent is formed, boron reagent is added for a reaction, and the 3, 6-dihydro-2H-pyrazine (thiazine) furan-4-boric acid ester is obtained. By means of the method, ultralow temperature, column chromatography and palladium catalyzed coupling in a literature method are avoided, raw materials are easy to obtain, cost is low, conditions are mild, and the method has potential industrial application and amplification prospect.
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Paragraph 0014
(2016/10/31)
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- HETEROCYCLICALLY SUBSTITUTED ARYL COMPOUNDS AS HIF INHIBITORS
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The present application relates to novel aryl compounds with heterocyclic substituents, processes for their preparation, their use for treatment and/or prevention of diseases and their use for the preparation of medicaments for treatment and/or prevention
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Paragraph 1214; 1215; 1216; 1217
(2013/08/14)
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