51417-51-7Relevant articles and documents
7-Pyridylindoles: Synthesis, structure, and properties
Mudadu, Maria Salvatora,Singh, Ajay,Thummel, Randolph P.
, p. 7611 - 7617 (2006)
(Chemical Equation Presented) A series of three isomeric 7-pyridylindoles (7-PIs) are prepared where the pyridine attachment is through C2, C3, or C4. These systems are prepared by a combination of the Bartoli reaction and the Stille coupling with an appropriate pyridyl stannane. By treatment with CH 3I, the 7-PIs can be converted to their pyridinium salts. Deprotonation at the NH of these salts leads to a zwitterion which, in the 4-pyridyl system, also exists as a neutral isomer. The photophysical and NMR properties of these systems are discussed. All three pyridylindoles are analyzed by X-ray crystallography and shown to exist in different states of aggregation dictated by the formation of intra- and intermolecular H-bonds.
A short synthesis of hippadine
Harrowven, David C.,Lai, Darren,Lucas, Matthew C.
, p. 1300 - 1302 (1999)
A synthesis of the pyrrolophenanthridone alkaloid hippadine is described. The approach features the use of a low temperature Ullman type coupling reaction to effect construction of the pentacyclic skeleton and an unusual methylene oxidation promoted by barium manganate.
CONDENSED HETEROAROMATIC RING SYSTEMS. XXIII. A CONCISE SYNTHESIS OF HIPPADINE
Sakamoto, Takao,Yasuhara, Akito,Kondo, Yoshinori,Yamanaka, Hiroshi
, p. 2597 - 2600 (1993)
Hippadine, a pyrrolophenanthridine alkaloid, was synthesized in 39percent overall yield of three steps using the palladium-catalyzed cross-coupling reaction of 2,6-dibromoaniline with (Z)-1-tributylstannyl-2-ethoxyethene as a key step.
Covalent Organic Frameworks toward Diverse Photocatalytic Aerobic Oxidations
Liu, Shuyang,Tian, Miao,Bu, Xiubin,Tian, Hua,Yang, Xiaobo
supporting information, p. 7738 - 7744 (2021/05/07)
Photoactive two-dimensional covalent organic frameworks (2D-COFs) have become promising heterogenous photocatalysts in visible-light-driven organic transformations. Herein, a visible-light-driven selective aerobic oxidation of various small organic molecules by using 2D-COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone-based 2D-COF-1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2-chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale-up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D-COF-1 in photocatalytic cycle.
Novel Arylindigoids by Late-Stage Derivatization of Biocatalytically Synthesized Dibromoindigo
Schnepel, Christian,Dodero, Veronica I.,Sewald, Norbert
supporting information, p. 5404 - 5411 (2021/03/03)
Indigoids represent natural product-based compounds applicable as organic semiconductors and photoresponsive materials. Yet modified indigo derivatives are difficult to access by chemical synthesis. A biocatalytic approach applying several consecutive selective C?H functionalizations was developed that selectively provides access to various indigoids: Enzymatic halogenation of l-tryptophan followed by indole generation with tryptophanase yields 5-, 6- and 7-bromoindoles. Subsequent hydroxylation using a flavin monooxygenase furnishes dibromoindigo that is derivatized by acylation. This four-step one-pot cascade gives dibromoindigo in good isolated yields. Moreover, the halogen substituent allows for late-stage diversification by cross-coupling directly performed in the crude mixture, thus enabling synthesis of a small set of 6,6’-diarylindigo derivatives. This chemoenzymatic approach provides a modular platform towards novel indigoids with attractive spectral properties.
Rh(III)-Catalyzed Selective C7 Halogenation of Indolines
Manisha,Gupta, Shiv Shankar,Dhiman, Ankit Kumar,Sharma, Upendra
, p. 5443 - 5448 (2021/10/25)
An efficient Rh-catalyzed catalytic method has been developed for selective C7 halogenation of N-pyrimidyl indolines with N-halosuccinimides (Cl, Br, I) to produce corresponding halides in good to excellent yields. The advantages of this strategy include
Pd-Catalyzed C-H Halogenation of Indolines and Tetrahydroquinolines with Removable Directing Group
Ahmad, Ashfaq,Dutta, Himangsu Sekhar,Kumar, Mohit,Khan, Afsar Ali,Raziullah,Koley, Dipankar
, p. 5870 - 5875 (2020/07/30)
Pd-catalyzed directing-group-assisted regioselective halogenations to C7 of indolines and C8 of tetrahydroquinolines were achieved in good to excellent yields. The practicality and utility of the developed method have been illustrated by various functiona
Electron Transfer Photoredox Catalysis: Development of a Photoactivated Reductive Desulfonylation of an Aza-Heteroaromatic Ring
Qiang-Liu,Liu, Yu-Xiu,Song, Hong-Jian,Wang, Qing-Min
supporting information, p. 3110 - 3115 (2020/07/04)
Herein, we report a protocol for desulfonylation of aza-heteroaromatic rings via photoinduced electron transfer and hydrogen atom transfer. This general protocol has a wide substrate range and moderate to good yields. The utility of the method was demonstrated by the chemoselective desulfonylation of a molecule containing both an aliphatic and an aromatic sulfonamide. (Figure presented.).
Synthesis of phenanthridine skeletal Amaryllidaceae alkaloids
Fan-Chiang, Tai-Ting,Wang, Hung-Kai,Hsieh, Jen-Chieh
, p. 5640 - 5645 (2016/08/17)
Strategies for the synthesis of Amaryllidaceae alkaloids, including crinasiadine, trisphaeridine, bicolorine, N-methylcrinasiadine, 5,6-dihydrobicolorine, galanthindole, lycosinine A and lycosinine B were reported. Investigation of optionally synthetic routes to approach bicolorine, 5,6-dihydrobicolorine, trisphaeridine and N-methylcrinasiadine were demonstrated as well. In addition, three structurally related alkaloids galanthindole, lycosinine A and lycosinine B were concisely prepared by using Suzuki coupling reaction as the key step.
Formal Total Synthesis of Diazonamide A by Indole Oxidative Rearrangement
David, Nadège,Pasceri, Raffaele,Kitson, Russell R. A.,Pradal, Alexandre,Moody, Christopher J.
supporting information, p. 10867 - 10876 (2016/07/27)
A short formal total synthesis of the marine natural product diazonamide A is described. The route is based on indole oxidative rearrangement, and a number of options were investigated involving migration of tyrosine or oxazole fragments upon oxidation of open chain or macrocyclic precursors. The final route proceeds from 7-bromoindole by sequential palladium-catalysed couplings of an oxazole fragment at C-2, followed by a tyrosine fragment at C-3. With the key 2,3-disubstituted indole readily in hand, formation of a macrocyclic lactam set the stage for the crucial oxidative rearrangement to a 3,3-disubstituted oxindole. Notwithstanding the concomitant formation of the unwanted indoxyl isomer, the synthesis successfully delivered, after deprotection, the key oxindole intermediate, thereby completing a formal total synthesis of diazonamide A.
