18102-31-3Relevant academic research and scientific papers
Tandem Oxidative Phenol Dearomatization/Formal [3+2] Annulation Protocol en Route to Highly Functionalized Benzothiophenes
Chittimalla, Santhosh Kumar,Bandi, Chennakesavulu
, p. 1051 - 1056 (2017)
A new strategy for the synthesis of benzothiophenes through formal [3+2] annulation of sulfanylacetaldehyde and cyclohexa-2,4-dien-1-one monoketals has been developed. This approach relies on the ease of aromatization of tetrahydrobenzothiophenone derivatives prepared by the aforementioned protocol. Given the ready accessibility of various substituted cyclohexa-2,4-dien-1-one monoketals, a range of benzothiophene derivatives became available.
Total synthesis of the isoquinolinium metabolite ETM-204 of Trabectidin
Breinbauer, Rolf,Gissing, Simon,Lembacher-Fadum, Christian,Pour, Georg
, (2021/10/23)
Ecteinascidin-743 (Trabectidin, Trabectedin, Yondelis) is a synthetically obtained pharmaceutical drug originally isolated from a marine tunicate. Trabectedin is used for the chemotherapy of soft-tissue sarcoma and ovarian cancer. Th
Role of Catalyst Support's Physicochemical Properties on Catalytic Transfer Hydrogenation over Palladium Catalysts
Batalha, Nuno,Fraga, Gabriel,Hasan, M. D.,Konarova, Muxina,Laycock, Bronwyn,Pratt, Steven,Santos, Mirella S.
, p. 5191 - 5202 (2021/10/29)
Catalytic transfer hydrogenation (CTH) is a promising reaction for valorisation of bio-based feedstocks via hydrogenation without needing to use H2. Unlike standard hydrogenation, CTH occurs via dehydrogenation (DHD) of a hydrogen donor (H-donor) and hydrogenation (HYD) of a substrate. Therefore, the “ideal” CTH catalyst must balance the catalysis of both reactions to maximize the hydrogen transfer between H-donor and substrate with minimal H2 loss to gas (high atom efficiency). Additionally, the H-donor must be highly stable to prevent secondary reactions with the substrate. Herein we study the impact of the catalyst's properties on CTH of guaiacol using bicyclohexyl, a liquid organic hydrogen carrier, as a H-donor. The reaction was promoted by palladium dispersed on three typical support materials (γ-Al2O3, MgO, and SiO2). The performance of these catalysts in the conversion of bicyclohexyl and guaiacol was evaluated, allowing to estimate the H-transfer efficiency, as well as the potential for recycling the spent H-donor (bicyclohexyl). The apparent activation energies for DHD of bicyclohexyl and HYD of guaiacol revealed that slow DHD combined with fast HYD, as is the case with Pd/MgO, favours hydrogen transfer efficiency and selectivity towards hydrogenated products. In addition, an investigation of the DHD of bicyclohexyl and HYD of guaiacol independently showed that the affinity between the organic molecules and the support significantly impacts CTH. Indeed, Pd/SiO2 was highly active for both reactions individually and almost inactive for CTH. Consequently, these findings highlight the importance of the interaction between solvent-substrate-support in designing catalysts for transfer hydrogenation.
SUBSTITUTED-N-HETEROARYL COMPOUNDS AND USES THEREOF
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Page/Page column 63; 77, (2020/01/24)
The present disclosure relates generally to compounds useful for the treatment and/or enhancement of cognitive function and negative symptoms associated with central nervous system disorders where the circuitry involving fast spiking PV+ interneurons and the production of cortical gamma oscillations is disrupted. The subject disclosure enables the manufacture of medicaments as well as compositions containing same for use in methods of therapy and prophylaxis of cognitive dysfunction and negative symptoms.
SUBSTITUTED-PYRIDINYL COMPOUNDS AND USES THEREOF
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Page/Page column 37; 91-92, (2020/01/10)
The present application relates generally to compounds useful for the treatment and/or enhancement of cognitive dysfunction and negative symptoms associated with CNS disorders where the circuitry involving fast spiking PV+ interneurons and the production of cortical gamma oscillations is disrupted. The subject disclosure enables the manufacture of medicaments as well as compositions containing same for use in methods of therapy and prophylaxis of cognitive dysfunction and negative symptoms.
Tuning the Reactivity of Peroxo Anhydrides for Aromatic C-H Bond Oxidation
Pilevar, Afsaneh,Hosseini, Abolfazl,?ekutor, Marina,Hausmann, Heike,Becker, Jonathan,Turke, Kevin,Schreiner, Peter R.
, p. 10070 - 10079 (2018/09/06)
Phenol moieties are key structural motifs in many areas of chemical research from polymers to pharmaceuticals. Herein, we report on the design and use of a structurally demanding cyclic peroxide (spiro[bicyclo[2.2.1]heptane-2,4′-[1,2]dioxolane]-3′,5′-dione, P4) for the direct hydroxylation of aromatic substrates. The new peroxide benefits from high thermal stability and can be synthesized from readily available starting materials. The aromatic C-H oxidation using P4 exhibits generally good yields (up to 96%) and appreciable regioselectivities.
α-Halogenation as a Strategy to Functionalize Cyclohexa-2,4-dienones
Chittimalla, Santhosh Kumar,Koodalingam, Manikandan,Gadi, Vinod Kumar,Anaspure, Prasad
, p. 475 - 480 (2017/02/24)
A facile pyridine-mediated α-halogenation approach to functionalize cyclohexa-2,4-dienones is developed. A range of reactions, including organometallic coupling protocols, have been applied on these newly obtained halogenated cyclohexa-2,4-dienones, and the results are presented herein.
Examination of Selectivity in the Oxidation of ortho- and meta-Disubstituted Benzenes by CYP102A1 (P450 Bm3) Variants
Munday, Samuel D.,Dezvarei, Shaghayegh,Lau, Ian C.-K.,Bell, Stephen G.
, p. 2512 - 2522 (2017/07/12)
Cytochrome P450 CYP102A1 (P450 Bm3) variants were used to investigate the products arising from the P450 catalysed oxidation of a range of disubstituted benzenes. The variants used all generated increased levels of metabolites compared to the wild-type enzyme. With ortho-halotoluenes up to six different metabolites could be identified whereas the oxidation of 2-methoxytoluene generated only two aromatic oxidation products. Addition of an ethyl group markedly shifted the selectivity for oxidation to the more reactive benzylic position. Epoxidation of an alkene was also preferred to aromatic oxidation in 2-methylstyrene. Significant minor products arising from the migration of one substituent to a different position on the benzene ring were formed during certain P450-catalysed substrate turnovers. For example, 2-bromo-6-methylphenol was formed from the turnover of 2-bromotoluene and the dearomatisation product 6-ethyl-6-methylcyclohex-2,4-dienone was generated from the oxidation of 2-ethyltoluene. The RLYF/A330P variant altered the product distribution enabling the generation of certain metabolites in higher quantities. Using this variant produced 4-methyl-2-ethylphenol from 3-ethyltoluene with ≥90 % selectivity and with a biocatalytic activity suitable for scale-up of the reaction.
Access to 3-arylindoles through a tandem one-pot protocol involving dearomatization, a regioselective michael addition reaction, and rearomatization
Chittimalla, Santhosh Kumar,Bandi, Chennakesavulu,Putturu, Sireesha,Kuppusamy, Rajesh,Boellaard, Kevin Christopher,Tan, David Chu Aan,Lum, Demi Ming Jie
, p. 2565 - 2575 (2014/05/06)
A facile, general and rapid protocol for the introduction of oxygenated aryls at the 3-position of indoles is described. This approach consists of a tandem dearomatization, a regioselective Michael addition reaction, and rearomatization in a one-pot three-step sequence to obtain 3-arylindoles in good yields. A non-metal mediated detour method for installing oxygenated aryls at the 3-position of indoles is described. Copyright
Facile and regioselective dealkylation of alkyl aryl ethers using niobium(V) pentachloride
Sudo, Yukinori,Arai, Shigeru,Nishida, Atsushi
, p. 752 - 758 (2007/10/03)
A simple and facile method for the cleavage of carbon-oxygen bonds promoted by niobium pentachloride(V) is described. Excellent yields and regioselectivities were observed with various alkyl aryl ethers to give the phenols. NMR studies revealed the formation of monoaryloxy niobium salt(V), and a neighboring-group effect may play a significant role in the regioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
