3274-56-4Relevant articles and documents
Gold(I)-Catalyzed Cascade Hydroarylation/Cycloaromatization to Indolizines via Pyridine Ring Construction
Li, Xiangdong,Xie, Xin,Liu, Yuanhong
, p. 3688 - 3699 (2016)
An efficient and atom-economic method for the synthesis of multisubstituted indolizines via gold-catalyzed cascade hydroarylation/cycloaromatization reaction of α-(N-pyrrolyl)ketones with alkynes is described. The reaction is realized through the construction of the pyridine ring of indolizines, which allows the regioselective incorporation of a wide range of functionalities on the pyridine unit.
Efficient Far-Red/Near-IR Absorbing BODIPY Photocages by Blocking Unproductive Conical Intersections
Shrestha, Pradeep,Dissanayake, Komadhie C.,Gehrmann, Elizabeth J.,Wijesooriya, Chamari S.,Mukhopadhyay, Atreyee,Smith, Emily A.,Winter, Arthur H.
supporting information, p. 15505 - 15512 (2020/10/20)
Photocages are light-sensitive chemical protecting groups that give investigators control over activation of biomolecules using targeted light irradiation. A compelling application of far-red/near-IR absorbing photocages is their potential for deep tissue activation of biomolecules and phototherapeutics. Toward this goal, we recently reported BODIPY photocages that absorb near-IR light. However, these photocages have reduced photorelease efficiencies compared to shorter-wavelength absorbing photocages, which has hindered their application. Because photochemistry is a zero-sum competition of rates, improvement of the quantum yield of a photoreaction can be achieved either by making the desired photoreaction more efficient or by hobbling competitive decay channels. This latter strategy of inhibiting unproductive decay channels was pursued to improve the release efficiency of long-wavelength absorbing BODIPY photocages by synthesizing structures that block access to unproductive singlet internal conversion conical intersections, which have recently been located for simple BODIPY structures from excited state dynamic simulations. This strategy led to the synthesis of new conformationally restrained boron-methylated BODIPY photocages that absorb light strongly around 700 nm. In the best case, a photocage was identified with an extinction coefficient of 124000 M-1 cm-1, a quantum yield of photorelease of 3.8%, and an overall quantum efficiency of 4650 M-1 cm-1 at 680 nm. This derivative has a quantum efficiency that is 50-fold higher than the best known BODIPY photocages absorbing >600 nm, validating the effectiveness of a strategy for designing efficient photoreactions by thwarting competitive excited state decay channels. Furthermore, 1,7-diaryl substitutions were found to improve the quantum yields of photorelease by excited state participation and blocking ion pair recombination by internal nucleophilic trapping. No cellular toxicity (trypan blue exclusion) was observed at 20 μM, and photoactivation was demonstrated in HeLa cells using red light.
Preparation method of 2,4-di-substituted pyrrole derivative
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Paragraph 0020; 0021; 0022; 0023, (2018/07/30)
The invention discloses a preparation method of a 2,4-di-substituted pyrrole derivative. The reaction equation is shown in the description. By adopting the method, a pyrrole derivative with a plurality of substituents which is difficult to obtain with other methods can be synthesized.
α-Unsubstituted Pyrroles by NHC-Catalyzed Three-Component Coupling: Direct Synthesis of a Versatile Atorvastatin Derivative
Fleige, Mirco,Glorius, Frank
supporting information, p. 10773 - 10776 (2017/08/22)
A practical one-pot cascade reaction protocol provides direct access to valuable 1,2,4-trisubstituted pyrroles. The process involves an N-heterocyclic carbene (NHC)-catalyzed Stetter-type hydroformylation using glycolaldehyde dimer as a novel C1 building-block, followed by a Paal-Knorr condensation with primary amines. The reaction makes use of simple and commercially available starting-materials and catalyst, an important feature regarding applicability and utility. Low catalyst loading under mild reaction conditions afforded a variety of 1,2,4-substituted pyrroles in a transition-metal-free reaction with high step economy and good yields. This methodology is applied in the synthesis of a versatile Atorvastatin precursor, in which a variety of modifications at the pyrrole core structure are possible.
