نتایج جستجو برای: azomethine
تعداد نتایج: 799 فیلتر نتایج به سال:
Azomethine ylides were generated from Schiffs bases of S-allylcysteine methyl ester and their intramolecular 1,3-dipolar cycloadditions were studied. These reactions led to the synthesis of thieno[3,4b]pyrrole derivatives in good yield.
N-Metallated azomethine ylide generated from methyl (E)-N-benzylideneglycinate, LiBr and triethylamine underwent cycloaddition to quinolyl , -unsaturated ketones with excellent diastereoselectivity to afford new functionalised 3-pyrrolidinylquinoline derivatives.
In the title compound, C(15)H(18)N(2)O(4), the aromatic rings on the azomethine double bond are trans to each other [C-C=N-C torsion angle = -178.29 (12)°] and they are approximately coplanar, the dihedral angle between them being 5.0 (1)°.
The title compound, C(15)H(20)BrN(3)O(2)S, crystallizes in the thio-amide form and adopts an E,E conformation with respect to the azomethine and hydrazinic bonds, respectively. The mol-ecules are paired through N-H⋯O and O-H⋯S hydrogen bonds, leading to the formation of centrosymmetric dimers in the crystal. These dimers are stacked along the a axis and are inter-connected through N-H⋯S hydroge...
A direct and facile synthesis of highly functional 5-aza-spiro[2,4]heptanes, a valuable structural motif for drug discovery, is developed via catalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time.
Generation of azomethine imine and its scope in regioselective 1,3-dipolar cycloaddition (DC) of imine with PhIO toward highly substituted Delta(2)-1,2,4-triazoline, 1,2,4-triazole, and their fused, chiral, and sugar-based analogues are demonstrated.
The generation of azomethine ylides from the readily accessible hemiaminals 3 and 8 or from iminium salt 10 was studied. Compounds 8 gave anti- and syn-cycloadducts containing the quinocarcin core through a catalyst-free dehydration process.
[3+2] Cycloaddition of azomethine imines with electron-deficient terminal alkynes was smoothly catalyzed by a chiral bis(imidazolidine)pyridine-CuOAc complex to give bicyclic pyrazolo[1,2-a]pyrazolone derivatives with up to 74% ee.
Condensation of an aldehyde with an α-amino-ester, followed by a tandem process involving cyclization to a seven-membered ring, deprotonation to an intermediate azomethine ylide and intramolecular dipolar cycloaddition gave tricyclic products related to stenine and neostenine.
Generation and cycloaddition of less- or non-stabilized azomethine ylides, or nitrile ylide equivalents, via unprecedented 1,4-stannatropy of N-(tributylstannylmethyl)thioamides were achieved. The reactions with dipolarophiles, such as electron-deficient alkenes and alkynes, afforded corresponding pyrrolidine and pyrrole derivatives effectively.
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