A new one-pot preparation of 4-tetrazolyl-3,4-dihydroquinazolines
has been reported. The Ugi-azide reactions of 2-azidobenzaldehydes,
amines, trimethylsilyl azide, and isocyanides produced azide intermediates
without separation, which were treated with isocyanides to give 4-tetrazolyl-3,4-dihydroquinazoline
derivatives through a sequential Palladium-catalyzed azide-isocyanide
cross-coupling/cyclization reaction in moderate to good yields. The
biological evaluation demonstrated that compound 6c inhibited
breast cancer cells well and displayed broad applications for synthesis
and medicinal chemistry.
A new, one-pot method for the synthesis of 4H-3,1-benzoxazine derivatives has been developed. The Passerini-azide reactions of 2-azidobenzaldehydes, trimethylsilyl azide, and isocyanides produced azide intermediate without separation, which then reacted with isocyanides to give 4H-3,1-benzoxazine derivatives via a tandem one-pot palladium-catalyzed azide–isocyanide coupling/cyclization reaction in moderate to good yields.
An efficient asymmetric [4+2] cyclization of α,β-unsaturated 2-acyl imidazoles with ortho‐hydroxyphenyl‐substituted para‐quinone methide derivatives catalyzed by a chiral-at-metal rhodium complex has been developed. The enantioenriched chroman derivatives bearing three contiguous...
A simple one pot synthesis of polysubstituted pyrroles via ketenimine formation/Ag(I)-catalyzed alkyne cycloisomerisation has been developed. The easily accessible phosphorane ylide derivatives reacted with isocyanates, producing highly active ketenimines that were then treated with amines, which afforded substituted pyrroles by a 5-exo-dig cyclization/isomerization in the presence of a Ag(I) catalyst in good overall yields.
Two new half-sandwich zirconium(IV) complexes bearing salicylaldimine ligands of the type Cp*Zr[2-t Bu-4-R-6-(CH=N i Pr)C 6 H 2 O]Cl 2 [R=H(1), t Bu(2)] were prepared by the reaction of Cp*ZrCl 3 with the corresponding lithium of salicylaldimine ligands 2-t Bu-4-R-6-(CH=N i Pr)C 6 H 2 OLi[R=H(LiLa), t Bu(LiLb)]. Complexes 1 and 2 were characterized by 1 H NMR, 13 C NMR spectroscopy and elemental analysis. When activated with Al i Bu 3 and Ph 3 CB(C 6 F 5 ) 4 , both complexes 1 and 2 exhibited reasonable catalytic activities for ethylene polymerization, producing polyethylenes with moderate molecular weight. Complexes 1 and 2 also exhibited reasonable catalytic activities for ethylene copolymerization with 1-hexene, producing poly(ethylene-co-1-hexene)s with moderate molecular weight and reasonable 1-hexene content.
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