25809-80-7

Upstream product

• 551-93-9 2-aminoacetophenone 
• 103-71-9 phenyl isocyanate 
• 52670-38-9 2-ethynylaniline 
• 1224970-00-6 1-(o-ethynylphenyl)-3-phenylurea 
• 1610702-03-8 N-(4-methylene-1H-benzo[d][1,3]oxazin-2(4H)-ylidene)aniline 

Relevant academic research and scientific papers

Well-Defined Dinuclear Gold Complexes for Preorganization-Induced Selective Dual Gold Catalysis

The synthesis, reactivity, and potential of well-defined dinuclear gold complexes as precursors for dual gold catalysis are explored. Using the preorganizing abilities of the ditopic PNHPiPr(LH) ligand, dinuclear AuI–AuIcomplex 1 and mixed-valent AuI–AuIIIcomplex 2 provide access to structurally characterized chlorido-bridged cationic species 3 and 4 upon halide abstraction. For 2, this transformation involves unprecedented two-electron oxidation of the redox-active ligand, generating a highly rigidified environment for the Au2core. Facile reaction with phenylacetylene affords the σ,π-activated phenylacetylide complex 5. When applied in the dual gold heterocycloaddition of a urea-functionalized alkyne, well-defined precatalyst 3 provides high regioselectivities for the anti-Markovnikov product, even at low catalyst loadings, and outperforms common mononuclear AuIsystems. This proof-of-concept demonstrates the benefit of preorganization of two gold centers to enforce selective non-classical σ,π-activation with bifunctional substrates.

Facile preparation of 3-substituted 2-quinazolinones via electrogenerated base

A new series of 3,4-disubstituted quinazolin-2-ones, with potential T-type calcium channel antagonist activity, and new 4-methylene-quinazolin-2-ones, promising catalysts as N-heterocyclic olefins, have been prepared in good yield by a simple reaction between 2-aminobenzophenone, or 2-aminoacetophenone, and cyanomethyl anion electrogenerated by acetonitrile reduction at a graphite electrode, followed by the addition of different organic isocyanates and subsequent heterocyclization.

Preparation method of 4-methylene quinazolinone (thione) derivatives

The invention discloses a preparation method of 4-methylene quinazolinone (thione) derivatives. The preparation method comprises the following steps: dissolving 2-aminoacetophenone derivatives with different substituents and phenyl iso (thio) cyanate deri

Gold(I)-catalyzed reactions of 1-(ortho-alkynylaryl)ureas: Highly selective heterocyclization and synthesis of mixed N,O-acetals

Readily available 1-(ortho-ethynylaryl)urea derivatives undergo a selective gold/silver {[AuCl(IPr)]/AgSbF6} catalyzed N-6-exo-dig or N-5- endo-dig heterocyclization process in dimethylform-amide (DMF) at 60 8C. Benzoxazine derivatives, i.e., the products of O-6-exo-dig ring closure through the urea oxygen, could be observed under catalytic conditions only when the N-3 basicity was substantially diminished, but were readily isolable in stoichiometric processes carried out at low temperature. The open chain amino O,O-acetals and a series of new cyclic mixed N,O-acetals containing the trifluoroethyl group were synthesized when the reactions were performed in ethanol or trifluoro-ethanol, respectively, as solvent. The procedure allows for an easy access to this versatile class of key intermediates in organic synthesis from simple starting materials. The effect of using either DMF or protic solvents on the course of the reactions is reported.

Competitive gold-activation modes in terminal alkynes: An experimental and mechanistic study

The competition between π- and dual σ,π-gold-activation modes is revealed in the gold(I)-catalyzed heterocyclization of 1-(o-ethynylaryl)urea. A noticeable effect of various ligands in gold complexes on the choice of these activation modes is described. The cationic [Au(IPr)]+ (IPr=2,6-bis(diisopropylphenyl)imidazol-2-ylidene) complex cleanly promotes the π activation of terminal alkynes, whereas [Au(PtBu3)]+ favors intermediate σ,π species. In this experimental and mechanistic study, which includes kinetic and cross-over experiments, several σ-gold, σ,π-gold, and other gold polynuclear reaction intermediates have been isolated and identified by NMR spectroscopy, X-ray diffraction, or MALDI spectrometry. The ligand control in the simultaneous or alternative π- and σ,π-activation modes is also supported by deuterium-labeling experiments. Copyright

NHC-stabilized gold(I) complexes: Suitable catalysts for 6-exo-dig heterocyclization of 1-(o-Ethynylaryl)ureas

Figure presented 3-substituted 1-(o-ethynylaryl)ureas 1 selectively undergo either 6-exo-dig or 5-endo-dig cyclization (to give 4-methylene-3,4-quinazolin- 2-ones 2 or indoles 3, respectively) depending on the choice of the metal, ligand, and reaction conditions. The best results (up to 96% yield) in the preparation of the hydroamination products 2 are achieved with the highly bulky NHC-stabilized cationic gold(I) complex [Au(IPr)]+. Conversely, ureas bearing an internal alkyne lead to the 5-endo-dig cyclization mode regardless of the gold(I) complex employed. Whereas the nature of the substituent at N-3 does not have any influence on the regiochemistry observed, it does, in some cases, affect the efficiency of these transformations.