نتایج جستجو برای: heterocycle
تعداد نتایج: 914 فیلتر نتایج به سال:
The title compound, C(21)H(18)ClN, was synthesized by an enanti-oselective Brønsted acid-catalysed transfer hydrogenation reaction. The six-membered heterocycle adopts a half-chair conformation. It has the biphenyl residue in an axial position. The two rings of the biphenyl residue are almost coplanar [dihedral angle = 2.65 (9)°]. The crystal packing is stabilized by N-H⋯Cl hydrogen bonds, whic...
In the title adduct, C5H5NO·C8H12O4, the heterocycle exists in its zwitterionic form. The cyclo-hexane ring exhibits a chair conformation with the carb-oxy-lic acid groups in equatorial and axial orientations. In the crystal, mol-ecules are linked through charge-assisted O-H⋯O(-), N(+)-H⋯O(-) and N(+)-H⋯O hydrogen bonds, and an additional series of C-H⋯O contacts, giving a pleated two-dimension...
In the title compound, C(22)H(23)NO(4)·C(2)H(6)O, the pyridyl ring is aligned at 89.39 (2) and 87.41 (2)° with respect to the benzene rings, and the three rings connected to the methine C atom are arranged in a propeller-like conformation. The heterocycle is linked to the solvent mol-ecule by an O-H⋯N hydrogen bond.
The quinazolinone nucleus represents, among the class of fused heterocycles, a very important scaffold to obtain molecules with biological activities. A review literature revealed how such kind coming from natural or synthetic source, are associated wide range This is mainly directed towards 4-(3H)-quinazolinones N-3 substituted five membered heterocycle in which all possible combinations nitro...
The 2-pyrone moiety can be found in a large number of natural products with wide range biological activities, including antibiotic, antifungal, cytotoxic, neurotoxic, phytotoxic, anti-inflammatory and cardiotonic effects. With its heterocyclic structure encompassing the chemical nature conjugated dienes, lactones, Michael acceptors arenes, it undergo great variety transformations such as cycloa...
This study establishes a new trans-metal-trapping (TMT) procedure based on a mixture of LiTMP (the base) and tris(trimethylsilylmethyl)gallium [Ga(CH2 SiMe3 )3 , GaR3 ] (the trap) that, operating in a tandem manner, is effective for the regioselective deprotonation of sensitive diazines in hydrocarbon solution, as illustrated through reactions of pyrazine, pyridazine, and pyrimidine, as well as...
An enantioselective organocatalytic process for the one-step synthesis of poly-substituted 1,2,4-triazolines is reported. The heterocycle formation is believed to go through a step-wise mechanism of nucleophilic addition of an azlactone to an azodicarboxylate in the presence of an organic base catalyst, followed by a TMSCHN2 mediated heterocyclization. Both theoretical calculations and experime...
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