نتایج جستجو برای: azomethine
تعداد نتایج: 799 فیلتر نتایج به سال:
We provide a comprehensive account of the 1,3-dipolar cycloaddition reactions of azomethine ylides with carbonyl dipolarophiles. Many different azomethine ylides have been studied, including stabilized and non-stabilized ylides. Of the carbonyl dipolarophiles, aldehydes including formaldehyde are the most studied, although there are now examples of cycloadditions with ketones, ketenes and carbo...
Azomethine (C=N) and azo (N=N) scaffolds are a part of structural units in poly(p-phenylene azomethine) (PAM) azo) (PAZ), respectively. Poly(p-phenylene vinylene) (PPV) is known to be one luminescent π-conjugated polymers, meanwhile PAM PAZ, which the aza-substituted PPV analogues, regarded as weak or no emissive materials. However, by boron complexation, intense emission can induced. Furthermo...
Cycloaddition is a fundamental transformation, featuring the assembly of complex cyclic molecules with multiple stereocenters. We report here silver-catalyzed [3+2]-cycloaddition 2,3-disubstituted cyclobutenones an array azomethine ylide...
A wide range of new dipoles and catalysts have been used in 1,3-dipolar cycloadditions of N-metalated azomethine ylides onto C60 yielding a full stereodivergent synthesis of pyrrolidino[60]fullerenes with complete diastereoselectivities and very high enantioselectivities. The use of less-explored chiral α-iminoamides as starting 1,3-dipoles leads to an interesting double asymmetric induction re...
A strategy for exo and enantioselective 1,3-dipolar cycloaddition of azomethine imines to 2-acryloyl-3-pyrazolidinone is described. The corresponding cycloadducts are isolated with high diastereoselectivities (up to >96:4 exo/endo) and enantioselectivities (up to 98% ee).
Conjugate acids of cyclic (amino)(phosphino)carbenes (P-NHCs) have been prepared, and several different processes have been observed during their deprotonation, which include the formation of a metastable P-NHC, an azomethine ylide, and a bicyclic phosphirane.
The title compound, C(21)H(26)N(2)O(4), adopts an E configuration with respect to the azomethine C=N bonds. The dihedral angle between the two rings is 8.16 (8)°. The crystal structure is stabilized by weak inter-molecular C-H⋯O inter-actions.
In the title compound, C(19)H(20)N(2)O(6), the azomethine [C=N = 1.269 (2) Å] double bond adopts an E conformation and the dihedral angle between the planes of the benzene rings is 17.41 (11)°. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R(2) (2)(16) loops. The dimers are connected by C-H⋯O and C-H⋯N hydrogen bonds, forming sheets lying parallel to (100).
The aromatic rings attached to the azomethine double bond in the title compound, C(14)H(17)N(3)O, are trans to each other [C-C=N-C torsion angle = 179.5 (1)°], and they are approximately coplanar [dihedral angle between the five- and six-membered rings = 13.7 (1)°].
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