58861-48-6Relevant articles and documents
Synthesis of Substituted Thiophenes through Dehydration and Heterocyclization of Alkynols
Chen, Lu,Chen, Zebin,Huang, Yubing,Ji, Xiaoliang,Li, Jiaming,Li, Jian,Li, Yibiao,Liu, Qiang,Liu, Yang
supporting information, p. 3555 - 3566 (2022/03/14)
A protocol was described for obtaining a variety of substituted thiophenes with functional potential via metal-free dehydration and sulfur cyclization of alkynols with elemental sulfur (S8) or EtOCS2K in moderate-to-good yields. The method provides the base-free generation of a trisulfur radical anion (S3?-) and its addition to alkynes as an initiator. This research broadens the applications of S3?-in the synthesis of sulfur-containing heterocycles.
Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
, p. 15665 - 15673 (2021/11/16)
Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
Preparation method of intermediate
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, (2020/06/29)
The invention discloses a preparation method for a Canagliflozin intermediate. The preparation method comprises the steps that substituted bromobenzene as a starting material is reacted with bisdiboron to prepare a boride, and then the Canagliflozin intermediate is prepared through a Suzuki coupling reaction, a Friedel-Crafts acylation reaction and a reduction reaction. The preparation method hasthe advantages that the intermediate product CZ-2 is prepared through the Suzuki coupling reaction, the conditions are mild and easy to operate and control, and the product yield and the product purity are high; aryl methyl is introduced through the Friedel-Crafts acylation reaction, a main chain is built, by means of the route, the yield is high, technological conditions are easy to control, andthe preparation method is suitable for large-scale industrial production.
Carbazole based Electron Donor Acceptor (EDA) catalysis for the synthesis of biaryl and aryl-heteroaryl compounds
Annes, Sesuraj Babiola,Ramesh, Subburethinam,Saravanan, Subramanian,Saritha, Rajendhiran
, p. 2510 - 2515 (2020/04/15)
A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl-heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.
Preparation method of canagliflozin intermediate 2-(4-fluorophenyl) thiophene
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Paragraph 0032-0066, (2021/01/04)
The invention relates to a preparation method of canagliflozin intermediate 2-(-4fluorophenyl) thiophene. The method comprises the following steps of: (1) enabling 2-bromothiophene to react with magnesium chips in a THF solvent to generate 2-thienyl magnesium bromide Grignard liquid; (2) carrying out catalytic Kumada coupling reaction on the 2-thienyl magnesium bromide Grignard liquid and p-fluorobromobenzene in the presence of a nickel or palladium complex as a catalyst, so as to obtain the 2-(-4fluorophenyl) thiophene. The method is good in product quality, high in yield, mild in reaction condition, simple to operate and easy to industrialize.
Access to Substituted Thiophenes through Xanthate-Mediated Vinyl C(sp2)-Br Bond Cleavage and Heterocyclization of Bromoenynes
Huang, Guoling,Li, Jian,Li, Jianrong,Li, Jiaming,Sun, Minghua,Zhou, Peng,Chen, Lu,Huang, Yubing,Jiang, Shaohua,Li, Yibiao
, p. 13037 - 13049 (2020/11/26)
An environmentally sustainable strategy for the chemoselective heterocyclization of bromoenynes through a transition-metal-free sulfuration/cyclization process is reported. Using inexpensive and safe EtOCS2K as a thiol surrogate and tetrabutylphosphonium bromide and H2O as a mixed solvent, the reaction provided a range of substituted thiophenes in moderate to good yields. In addition, 2,3,4,5-tetrasubstituted thiophenes were able to be prepared under mild reaction conditions by electrophilic heterocyclization with NH4I and EtOCS2K in good yields.
Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
supporting information, p. 1922 - 1927 (2020/02/04)
The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
METHOD FOR PRODUCING HALOGEN COMPOUND
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Paragraph 0121; 0122; 0123; 0124; 0125, (2019/06/25)
PROBLEM TO BE SOLVED: To provide a highly efficient and economically advantageous method for producing a halogen compound. SOLUTION: Provided is a method for converting a benzene derivative represented by the following formula (1) into a halogen compound by reacting the benzene derivative and a first halogenating agent selected from hydrogen halides and halide salts in the presence of at least one acid selected from sulfuric acid, methanesulfonic acid and trifluoromethanesulfonic acid and an oxidizing agent, or by reacting the benzene derivative and a second halogenating agent selected from N-halogen succinimide and 1,3-dihalogen-5,5-dimethylhydantoin in the presence of at least one acid selected from sulfuric acid and methanesulfonic acid. [In the formula, R1's are alkyl groups or the like; n is an integer of 1 to 4; and R2 is an aromatic ring group which may have a substituent group or a heterocyclic group which may have a substituent group.] SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
Orthogonal Nanoparticle Catalysis with Organogermanes
Fricke, Christoph,Sherborne, Grant J.,Funes-Ardoiz, Ignacio,Senol, Erdem,Guven, Sinem,Schoenebeck, Franziska
supporting information, p. 17788 - 17795 (2019/11/13)
Although nanoparticles are widely used as catalysts, little is known about their potential ability to trigger privileged transformations as compared to homogeneous molecular or bulk heterogeneous catalysts. We herein demonstrate (and rationalize) that nanoparticles display orthogonal reactivity to molecular catalysts in the cross-coupling of aryl halides with aryl germanes. While the aryl germanes are unreactive in LnPd0/LnPdII catalysis and allow selective functionalization of established coupling partners in their presence, they display superior reactivity under Pd nanoparticle conditions, outcompeting established coupling partners (such as ArBPin and ArBMIDA) and allowing air-tolerant, base-free, and orthogonal access to valuable and challenging biaryl motifs. As opposed to the notoriously unstable polyfluoroaryl- and 2-pyridylboronic acids, the corresponding germanes are highly stable and readily coupled. Our mechanistic and computational studies provide unambiguous support of nanoparticle catalysis and suggest that owing to the electron richness of aryl germanes, they preferentially react by electrophilic aromatic substitution, and in turn are preferentially activated by the more electrophilic nanoparticles.
Gold-Catalyzed C-H Functionalization with Aryl Germanes
Fricke, Christoph,Dahiya, Amit,Reid, William B.,Schoenebeck, Franziska
, p. 9231 - 9236 (2019/10/11)
The development of orthogonal Csp2-Csp2 coupling regimes to the omnipresent Pd-catalysis class would enable an additional dimension of modularity in the construction of densely functionalized biaryl motifs. In this context, the identification of potent functional groups for selective transformations is in high demand. Although organogermanium compounds are generally believed to be of low reactivity in homogenous catalysis, this report discloses the highly efficient and orthogonal reactivity of aryl germanes with arenes under gold catalysis. The method is characterized by mildness, the employment of an air- and moisture-stable gold catalyst, and robustness. Our mechanistic studies show that aryl germanes are highly reactive with Au(I) and Au(III). Our computational data suggest that the origin of this reactivity primarily lies in the relatively low bond dissociation energy and as such low distortion energy to reach the key bond activating transition state.
