نتایج جستجو برای: heterocyclic
تعداد نتایج: 9423 فیلتر نتایج به سال:
Heterocyclic compounds are those cyclic compounds in which one or more of the ring carbons are replaced by another atom. The non-carbon atoms in such rings are referred to as ‘‘heteroatoms.’’ Such bicyclic heterocyclic compounds containing pyrrole ring with benzene ring fused to a,b-position are known as Indoles. Indole has a benzene ring and pyrrole ring sharing one double bond. It is a hetero...
Unexpected and unprecedented directed remote lateral lithiation at one CH(CH3)2 of the 3-(2,6-di-isopropylphenyl) wingtip took place upon the reaction of functionalised N-heterocyclic carbene-type molecules with excess of LiCH2SiMe3, leading to dilithiated dianionic 4-amido-N-heterocyclic carbenes. DFT calculations show that the nature of the isolated species are under thermodynamic control.
Aryl aldehyde activation: Oxidative activation of 2-methylindole-3-carboxaldehyde (I) through N-heterocyclic carbene (NHC) organocatalysis generates heterocyclic ortho-quinodimethane (II) as a key intermediate. This intermediate then undergoes formal [4+2] cycloaddition with trifluoromethyl ketones or isatins to form polycyclic lactones containing a quaternary carbon center.
Oxazolidinone is a five-member heterocyclic ring exhibiting potential medicinal properties with preferential antibacterial activity. Scientists reported various synthetic procedures for this heterocyclic structure. Current review articles tried to cover each and every potential aspect of oxazolidinone like synthetic routes, pharmacological mechanism of action, medicinal properties, and current ...
An improved total synthesis of (-)-julocrotine in three steps from Cbz-glutamine, in 51% overall yield, is presented. To demonstrate the potential of the heterocyclic moiety for diversity oriented synthesis, a series of (-)-julocrotine analogues was synthesized by employing the heterocyclic precursor as an amino input in Ugi four-component reactions (Ugi-4CR) [1].
A wide range of 2-pyridyl and other difficult-to-access heterocyclic N-methyliminodiacetic acid boronates can be readily prepared from the corresponding bromides via a new method involving direct transligation of 2-heterocyclic trialkoxyborate salts with N-methyliminodiacetic acid (MIDA) at elevated temperatures.
Dimesitylphosphinoisoprene 9a reacts with a series of R-B(C6F5)2 boron Lewis acids by isomerization and subsequent 1,4-P/B addition to give the heterocyclic phosphonium/borate zwitterionic products 13. Subsequent hydride abstraction from the isoprenyl derived methyl group by trityl cation proceeds with elimination of the R-B(C6F5)2 reagent to give the heterocyclic phosphonium system 20.
The results of two epidemiological studies suggest that high intake of heterocyclic amines, which are formed on the surface of meats cooked at high temperatures, might be associated with increased risk of esophageal or cardia cancers. Our aim was to further investigate heterocyclic amine intake and risk of these cancers. We examined data from a nationwide, population-based, case-control study o...
The results presented in this account deal with the synthesis of acyclic αor β-aminophosphonates or phosphinates and with the synthesis of heterocyclic compounds, where the phosphorus and/or the nitrogen atoms can be embedded in the heterocyclic core, showing new perspectives in bioactive molecules.
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