- Preparation process for 5-formylfuran-3-boronic acid
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The invention discloses a preparation process for 5-formylfuran-3-boronic acid, belonging to the technical field of synthesis of pharmaceutical intermediates. The invention aims to overcome the problem that the preparation of 5-formylfuran-3-boronic acid in the prior art is limited. According to a technical scheme in the invention, furfural acetal is used as a raw material and subjected to a metallization reaction with a metallizing agent under the action of a catalyst and under stirring; boric acid ester is added into a solvent having undergone the metallization reaction, and complete conversion is realized through stirring so as to obtain a mixture of an acetal-protected furfural-4-borate and the solvent; the mixture obtained in the previous step S2 is subjected to low-temperature distillation so as to obtain a low-boiling-point substance, the low-boiling-point substance is cooled to room temperature and then added to a perchloric acid solvent having a pH value of 0.7 to 1.1, and mixing under stirring is carried out in a low-temperature environment; a mixed solution obtained in the previous stepS3 is filtered by a needle felt to obtain a precipitate; and the precipitate is washedwith methyl isobutyl ketone and then dried under reduced pressure to obtain 5-formylfuran-3-boronic acid. The preparation process of the invention achieves the effects of high yield and high purity.
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Paragraph 0014; 0015
(2019/10/01)
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- METHOD FOR PRODUCING 2-FORMYLFURAN-4-BORONIC ACID BY THE METALATION OF 4-HALOFURFURAL ACETALS IN THE PRESENCE OF SUITABLE BORONIC ACID ESTERS OR ANHYDRIDES
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The invention relates to a method for producing furfural-4-boronic acid by the reaction of furfural acetals (I), which are substituted by halogen in position 4, with boronic acid esters or anhydrides (II), by the subsequent metalation of compound (I) and the simultaneous or subsequent reaction with a boronic acid ester or anhydride (II) to form an acetal-protected furfural-4-boronic acid ester. The product is then subjected to an acid hydrolysis, in which the acetal protection group is eliminated, to form furfural-4-boronic acid (III). In said formulae: X represents chlorine, bromine or iodine; R represents a branched, unbranched and/or cyclic, optionally substituted C1-C20 and in particular C1-C8 alkyl group, an optionally substituted C6-C12 aryl group or an optionally substituted C3-C8 cycloalkyl group, whereby the two groups R together can form a ring; R', R'', R''' independently of one another represent acylic or cyclic, branched or unbranched, optionally substituted C1-C20 alkyl groups, or optionally substituted aryl groups, whereby optionally two of the groups R', R'' and R''' together form a ring, or represent additional groups B(OR)3.
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Page/Page column 7
(2008/06/13)
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