New approaches to side-chain fluorinated bioimidazoles: 4-alkynylimidazoles as substrates for fluorination
作者:Bohumil Dolensky、Kenneth L Kirk
DOI:10.1016/s0022-1139(03)00197-0
日期:2003.11
3b met with failure. Reduction of the ester gave the hydroxymethyl-substituted acetylene 4. Addition of “FBr” to this substrate and reductive removal of bromine from the product produced fluoroolefins 12, precursors to E- and Z-β-fluorourocanic acids. The same fluoroolefins can be used as intermediates in the synthesis of β-fluorohistidinols.
已经制备了4-炔基咪唑,并且已经研究了它们作为“ FBr”添加底物(NBS + Et 3 N·3HF)的行为。容易Markownikov除了ethylnylimidazole 2得到fluorobromoolefin 9A,对于2-咪唑基-2-氟-1-乙烯基部分的电势的合成子。2的锂盐与草酸二乙酯反应生成咪唑基丙炔酸酯3b。但是,由于酯官能团的失活作用,所有试图向3b中添加“ FBr”的尝试都失败了。酯的还原得到羟甲基取代的乙炔4。向该底物添加“ FBr”,并从产物中还原除去溴,制得氟代烯烃12,氟代烯烃12是E-和Z -β-氟尿烷酸的前体。相同的氟代烯烃可以用作合成β-氟组氨酸的中间体。