4414-76-0Relevant academic research and scientific papers
Titanium(III)-Catalyzed Reductive Decyanation of Geminal Dinitriles by a Non-Free-Radical Mechanism
Weweler, Jens,Younas, Sara L.,Streuff, Jan
supporting information, p. 17700 - 17703 (2019/11/13)
A titanium-catalyzed mono-decyanation of geminal dinitriles is reported. The reaction proceeds under mild conditions, tolerates numerous functional groups, and can be applied to quaternary malononitriles. A corresponding desulfonylation is demonstrated as well. Mechanistic experiments support a catalyst-controlled cleavage without the formation of free radicals, which is in sharp contrast to traditional stoichiometric radical decyanations. The involvement of two TiIII species in the C?C cleavage is proposed, and the beneficial role of added ZnCl2 and 2,4,6-collidine hydrochloride is investigated.
Access to Spirocyclized Oxindoles and Indolenines via Palladium-Catalyzed Cascade Reactions of Propargyl Carbonates with 2-Oxotryptamines and Tryptamines
Nibbs, Antoinette E.,Montgomery, Thomas D.,Zhu, Ye,Rawal, Viresh H.
, p. 4928 - 4941 (2015/06/02)
(Chemical Equation Presented). Reported here are methods for the direct construction of a range of spirocyclized oxindoles and indolenines in good to excellent yields. Specifically, we report the palladium-catalyzed reactions of oxindoles and indoles, both functioning as bis-nucleophiles, with propargyl carbonates to afford spirocyclic products having an exocyclic double bond on the newly formed ring. The reaction proceeds through a process wherein the first nucleophilic unit on the oxindole or indole reacts with an allenyl-palladium species, formed from oxidative addition of Pd(0) to propargyl carbonates, to generate a π-allyl palladium intermediate that then reacts further with the second nucleophilic component of the oxindole or indole. The cascade process forges two bonds en route to spirocyclized oxindole and indolenine products. The use of chiral phosphines renders the cyclization sequence enantioselective, providing spirocyclic products with modest to good enantioselectivities.
Aqueous Titanium Trichloride Promoted Reductive Cyclization of o-Nitrostyrenes to Indoles: Development and Application to the Synthesis of Rizatriptan and Aspidospermidine
Tong, Shuo,Xu, Zhengren,Mamboury, Mathias,Wang, Qian,Zhu, Jieping
, p. 11809 - 11812 (2015/10/05)
Treatment of o-nitrostyrenes with aqueous TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)-H amination process. A range of functions such as halides (Cl, Br), carbonyl (ester, carbamate), cyano, hydroxy, and amino groups were tolerated. From β,β-disubstituted o-nitrostyrenes, 2,3-disubstituted indoles were formed by a domino reduction/cyclization/migration process. Mild conditions, simple experimental procedure, ready accessibility of the starting materials and good to excellent yields characterize the present transformation. The methodology was used as a key step in a concise synthesis of rizatriptan and a formal total synthesis of aspidospermidine. Mild and efficient treatment of o-nitrostyrenes with aqueous TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)-Hamination process. A concise synthesis of a marketed drug (rizatriptan) and a formal total synthesis of aspidospermidine featuring this novel N-heterocyclization process are reported.
Tryptophan 2,3-dioxygenase (TDO) inhibitors. 3-(2-(pyridyl)ethenyl)indoles as potential anticancer immunomodulators
Dolu?i?, Eduard,Larrieu, Pierre,Moineaux, Laurence,Stroobant, Vincent,Pilotte, Luc,Colau, Didier,Pochet, Lionel,Van Den Eynde, Beno?t,Masereel, Bernard,Wouters, Johan,Frédérick, Rapha?l
supporting information; experimental part, p. 5320 - 5334 (2011/10/02)
Tryptophan catabolism mediated by indoleamine 2,3-dioxygenase (IDO) is an important mechanism of peripheral immune tolerance contributing to tumoral immune resistance. IDO inhibition is thus an active area of research in drug development. Recently, our group has shown that tryptophan 2,3-dioxygenase (TDO), an unrelated hepatic enzyme also catalyzing the first step of tryptophan degradation, is also expressed in many tumors and that this expression prevents tumor rejection by locally depleting tryptophan. Herein, we report a structure-activity study on a series of 3-(2-(pyridyl)ethenyl)indoles. More than 70 novel derivatives were synthesized, and their TDO inhibitory potency was evaluated. The rationalization of the structure-activity relationships (SARs) revealed essential features to attain high TDO inhibition and notably a dense H-bond network mainly involving His55 and Thr254 residues. Our study led to the identification of a very promising compound (58) displaying good TDO inhibition (Ki = 5.5 μM), high selectivity, and good oral bioavailability. Indeed, 58 was chosen for preclinical evaluation.
Indolyl-3-acetaldoxime dehydratase from the phytopathogenic fungus Sclerotinia sclerotiorum: Purification, characterization, and substrate specificity
Pedras, M. Soledade C.,Minic, Zoran,Thongbam, Premila D.,Bhaskar, Vangala,Montaut, Sabine
experimental part, p. 1952 - 1962 (2011/06/26)
The purification and characterization of indolyl-3-acetaldoxime dehydratase produced by the plant fungal pathogen Sclerotinia sclerotiorum is described. The substrate specificity indicates that it is an indolyl-3-acetaldoxime dehydratase (IAD, EC 4.99.1.6), which catalyzes transformation of indolyl-3-acetaldoxime to indolyl-3-acetonitrile. The enzyme showed Michaelis-Menten kinetics and had an apparent molecular mass of 44 kDa. The amino acid sequence of IAD, determined using LC-ESI-MS/MS, identified it as the protein SS1G-01653 from S. sclerotiorum. IADSs was highly homologous (84% amino acid identity) to the hypothetical protein BC1G-14775 from Botryotinia fuckeliana B05.10. In addition, similarity to the phenylacetaldoxime dehydratases from Gibberella zeae (33% amino acid identity) and Bacillus sp. (20% amino acid identity) was noted. The specific activity of IADSs increased about 17-fold upon addition of Na2S2O4 under anaerobic conditions, but in the absence of Na2S2O 4 no significant change was observed, whether aerobic or anaerobic conditions were used. As with other aldoxime dehydratases isolated from microbes, the role of IADSs in fungal plant pathogens is not clear, but given its substrate specificity, it appears unlikely that IADSs is a general xenobiotic detoxifying enzyme.
Synthesis of 3-substituted indoles promoted by pulverization-activation method catalyzed by Bi(NO3)3·5H2O
Khodaei, Mohammad M.,Mohammadpoor-Baltork, Iraj,Memarian, Hamid R.,Khosropour, Ahmad R.,Nikoofar, Kobra,Ghanbary, Parvin
, p. 377 - 381 (2008/09/20)
(Chemical Equation Presented) A new, facile, efficient, "green" and chemoselective procedure for the synthesis of indole derivatives has been developed with pulverization-activation method catalyzed by Bi(NO 3)3·5H2O (PAMC- Bi(NO3) 3·5H2O) through grinding of indoles with aldehydes or Michael acceptors in the presence of catalytic amounts of Bi(NO 3)3·5H2O under solvent-free conditions.
Borrowing hydrogen: Indirect "Wittig" olefination for the formation of C-C bonds from alcohols
Black, Phillip J.,Edwards, Michael G.,Williams, Jonathan M. J.
, p. 4367 - 4378 (2007/10/03)
The successful development of an indirect three-step domino sequence for the formation of C-C bonds from alcohol substrates is described. An iridium-catalysed dehydrogenation of alcohol 1 affords the intermediate aldehyde 2. The desired C-C bond can then be formed by a facile Wittig olefination, yielding the intermediate alkene 3. In the final step the alkene is hydrogenated to afford the indirect Wittig product, the alkane 4. The key to this process is the concept of borrowing hydrogen; hydrogen removed in the initial dehydrogenation step is simply borrowed by the iridium catalyst. Functioning as a hydrogen reservoir, the catalyst facilitates C-C bond formation before subsequently returning the borrowed hydrogen in the final step. Herein we present full details of our examination into both the substrate and reaction scope and the limitations of the catalytic cycle. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Efficient michael addition of indoles using bismuthyl perchlorate as catalyst
Mohammadpoor-Baltork, Iraj,Reza Memarian, Hamid,Reza Khosropour, Ahmad,Nikoofar, Kobra
, p. 1837 - 1843 (2007/10/03)
An efficient method for Michael addition of indoles hasbeen developed using bismuthyl perchlorate (BiOClO4·xH2O) as catalyst. The reaction proceeds to give 3-substituted indoles excellently stirring indoles and Michael acceptors in acetonitrile in the presence of the catalyst at room temperature or in much shorter reaction times under sonication at ambient temperature.{A figure is presented}.
Conjugate addition of indoles and thiols with electron-deficient olefins catalyzed by Bi(OTf)3
Alam, M. Mujahid,Varala, Ravi,Adapa, Srinivas R.
, p. 5115 - 5119 (2007/10/03)
Conjugate addition of indoles and thiols with a variety of electron-deficient olefins mediated by a catalytic amount of Bi(OTf)3 at ambient temperature to afford the corresponding Michael adducts in good to excellent yields with high selectivity is reported.
Syntheses of 5a′-homo-vinblastine and congeners designed to establish structural determinants for isolation of atropisomers
Kuehne,Cowen,Xu,Borman
, p. 5303 - 5316 (2007/10/03)
The syntheses of 5a′-homo-vinblastine (3a) and its C-20′ methyl congener 62a were achieved. In contrast to vinblastine, these compounds did not allow isolation of atropisomers because of their lower conformational inversion barrier. However, annelation of a six-membered ring to the conformationally mobile D′-piperidine ring provided an isolated atropisomer 81a, which could be converted to its lower energy conformation 65a on heating. The 5a′-homo-vinblastine congeners 3a, 62a, and 65a showed vinblastine-like inhibition of tubulin polymerization and cytotoxicity to L1210 leukemia cells, albeit at lower potency for the latter activity, than that found with the corresponding compounds in the vinblastine series.
