7654-06-0Relevant articles and documents
AZIRIDINE-AZIRINE TRANSFORMATION BY 1,2-ELIMINATION via AN AZIRIDINYL CARBANION INTERMEDIATE
Atkinson, Robert S.,Kelly, Brian J.
, p. 2703 - 2704 (1989)
Desilylation of aziridine (5) by treatment with cesium fluoride in dry dimethylformamide in the presence of benzaldehyde followed by oxidation with manganese dioxide gives the benzoylaziridine (11) in 80percent yield: in the absence of benzaldehyde, the presumed aziridinyl carbanion intermediate (9) gives the aziridine (7) (58percent).
Copper-Catalyzed Sulfonyl Azide-Alkyne Cycloaddition Reactions: Simultaneous Generation and Trapping of Copper-Triazoles and -Ketenimines for the Synthesis of Triazolopyrimidines
Nallagangula, Madhu,Namitharan, Kayambu
, p. 3536 - 3539 (2017)
First simultaneous generation and utilization of both copper-triazole and -ketenimine intermediates in copper-catalyzed sulfonyl azide-alkyne cycloaddition reactions is achieved for the one-pot synthesis of triazolopyrimidines via a novel copper-catalyzed
Copper-Catalyzed Ring-Expansion Cascade of Azirines with Alkynes: Synthesis of Multisubstituted Pyridines at Room Temperature
Sujatha, Chandragiri,Bhatt, Chandra Shekar,Ravva, Mahesh Kumar,Suresh, Anil K.,Namitharan, Kayambu
, p. 3241 - 3244 (2018)
The first intermolecular ring-expansion cascade of azirines with alkynes for the synthesis of pyridines, enabled by a copper/triethylamine catalytic system via simultaneous generation and utilization of yne-enamine and skipped-yne-imine intermediates, is reported. Experimental as well as computational mechanistic studies revealed that the role of triethylamine is crucial in deciding the reaction pathway toward the pyridine products. This process offers a novel, one-step, direct, and practical strategy for the rapid construction of highly substituted pyridines under exceedingly mild conditions, and an installed alkyne functionality.
Synthesis of Isoquinoline Derivatives via Palladium-Catalyzed C?H/C?N Bond Activation of N-Acyl Hydrazones with α-Substituted Vinyl Azides
Jiang, Huanfeng,Nie, Biao,Ren, Qingyun,Wu, Wanqing,Zeng, Wei,Zhang, Ji,Zhang, Yingjun
, (2020/02/25)
A palladium-catalyzed cyclization of N-acetyl hydrazones with vinyl azides has been developed. Various substituted isoquinolines, including diverse fused isoquinolines can be prepared via this protocol in moderate to good yields. Mechanistic studies suggest that α-substituted vinyl azide serves as an internal nitrogen source. Also, C?H bond activation and C?N bond cleavage have been realized using hydrazone as directing group. (Figure presented.).
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.
, 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.
