已经设计和制备了一系列结合有1,4-二苯基-1,2,3-三唑的酰胺衍生物。X射线晶体学和(1D和2D)1 H NMR研究表明,这些化合物折叠成稳定的U形构象,这是由三唑C-5 H原子之间形成的三中心分子内C–H···O氢键驱动的和两个醚O原子。这种折叠结构使该1,4-二苯基-1,2,3-三唑骨架成为用作β-turn模拟物的良好候选者。为了证明这一点,已经进一步证明了由该β-转角基序诱导的β-发夹结构的形成。
已经设计和制备了一系列结合有1,4-二苯基-1,2,3-三唑的酰胺衍生物。X射线晶体学和(1D和2D)1 H NMR研究表明,这些化合物折叠成稳定的U形构象,这是由三唑C-5 H原子之间形成的三中心分子内C–H···O氢键驱动的和两个醚O原子。这种折叠结构使该1,4-二苯基-1,2,3-三唑骨架成为用作β-turn模拟物的良好候选者。为了证明这一点,已经进一步证明了由该β-转角基序诱导的β-发夹结构的形成。
An enantioselective addition reaction of alkynyl esters with imines was developed under asymmetric autotandem catalysis with a chiral Brønsted base. A chiral bis(guanidino)iminophosphorane organosuperbase, which has much higher basicity than that of conventional chiral organic bases, efficiently promoted both the intramolecular cyclization for the construction of a benzofuran ring or a benzothiophene
The regioselective cyclization/dehydration sequence of ortho diketo phenoxyethers induced by DBU has been explored. The results demonstrated a high degree of selectivity with preference for 6-exo-trig cyclization leading to the formation of gamma-benzopyranone derivatives in good yield. (C) 2013 Elsevier Ltd. All rights reserved.