Synthesis of Novel 2,3-Dihydroimidazo[2,1-<i>b</i>][1,3]oxazoles Through Intramolecular Nucleophilic<i>ipso</i>-Substitution in 2-Alkylsulfonylimidazoles
作者:José M. Villalgordo、Pilar Moreno、Montserrat Heras、Miguel Maestro
DOI:10.1055/s-2002-35982
日期:——
Readily available 2-(benzylsulfanyl)imidazoles 6, were studied as potential precursors toward the synthesis of novel diversely substituted 2,3-dihydroimidazo[2,1-b][1,3]oxazoles. Thus, the reaction between enolates derived from 6 and different electrophiles as well as the addition of Grignard reagents to the carbonyl group in 6 were explored. The formation of the fused imidazoxazoles 20 under mild conditions was successfully accomplished taking advantage of the key role played by the 2-alkylsulfonyl moiety in 19 as an efficient leaving group in intramolecular nucleophilic ipso-substitution reactions.
现成的2-(苄基硫基)咪唑6被研究为合成新型多种取代的2,3-二氢咪唑并[2,1-b][1,3]恶唑的前体。因此,探索了6衍生的烯醇与不同亲电体的反应以及将格氏试剂添加到6中的羰基。利用19中2-烷基磺酰基部分在分子内亲核同位素取代反应中作为有效离开基团的关键作用,在温和条件下成功完成了稠合咪唑恶唑20的形成。