نتایج جستجو برای: alternative substituents
تعداد نتایج: 311992 فیلتر نتایج به سال:
The title compound, C(10)H(19)NO(3), is a disubstituted piperidine bearing substituents in two equatorial positions. One of the substituents is a hy-droxy group bound to nitro-gen and the second a tert-butyl ester group bound to the carbon next to the endocyclic nitro-gen. Enanti-omers of the title compound form hydrogen-bridged dimers across a center of inversion.
Pseudopotential SCF calculations for YaC-X, Y =H, F; X=H, F, CI, PH2, PF2 and a simple model, simulating the substituents by a homogeneous, electric field, are presented in order to rationalize the substitution effect on the C-X bond.
The synthesis and structural characterization of a series of tripodal tris(phosphine) ligands, containing SiMe2 elbow groups, is described. The significant steric congestion in these ligands, due to the silylmethyl substituents, is manifest both in the solid-state structures and in the solution NMR spectra of the free ligands. Variable temperature 1H{31P} NMR studies of one of the ligands, CH3C...
The title compound, C24H21N3O3, crystallizes with two unique but closely r.m.s. overlay fit = 0.215 Å) comparable mol-ecules (1 and 2) in the asymmetric unit of the triclinic unit cell. In molecule 1, the dihedral angles between the central imidazlole ring and the benzene-ring substituents are 42.51 (9), 45.41 (9) and 56.92 (8)°, respectively. Comparable data for molecule 2 are 39.36 (10), 34.4...
Soil-dwelling, nitrogen-fixing rhizobia signal their presence to legume hosts by secreting lipo-chitooligomers (LCOs) that are decorated with a variety of chemical substituents. It has long been assumed, but never empirically shown, that the LCO backbone is synthesized first by NodC, NodB, and NodA, followed by addition of one or more substituents by other Nod proteins. By analyzing a collectio...
Keywords: Pyrrolodiazine Fluorescence Blue luminophores Microwave Cyc\oadditions A fast, efficient, general and environmentally friendly method for preparation of highly fluorescent derivatives containing the pyrrolodiazine moiety using microwave (MW) irradiation, in liquid phase, is reported. Under MW irradiation the yields are much higher, sometimes substantially (by almost double) and, the a...
Novel heteroleptic naphthalo-phthalocyaninates of lutetium possessing a symmetrical substituted naphthalocyanine deck were synthesized on the basis of two preformed synthetic blocks: naphthalocyanine ligand and lutetium phthalocyaninates. The compounds obtained were characterized by (1)H NMR and high-resolution MALDI-TOF/TOF mass spectrometry. The correlation between the nature of the substitue...
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