- Conjugate addition of grignard reagents to thiochromones catalyzed by copper salts: A unified approach to both 2-alkylthiochroman-4-one and thioflavanone
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Grignard reagents undergo conjugate addition to thiochromones catalyzed by copper salts to afford 2-substituted-thiochroman-4-ones, both 2-alkylthiochroman-4-ones and thioflavanones (2-arylthiochroman-4-ones), in good yields with trimethylsilyl chloride (TMSCl) as an additive. The best yields of 1,4-adducts can be attained with CuCN-2LiCl as the copper source. Excellent yields of 2-alkyl-substituted thiochroman-4-ones and thioflavanones (2-aryl substituted) are attained with a broad range of Grignard reagents. This approach works well with both alkyl and aromatic Grignard reagents, thus providing a unified synthetic approach to privileged 2-substituted thiochroman-4-ones and a potential valuable precursor for further synthetic applications towards many pharmaceutically active molecules. The use of commercially available and/or readily prepared Grignard reagents will expedite the synthesis of a large library of both 2-alkyl substituted thiochroman-4-ones and thioflavanones for additional synthetic applications.
- Austin, Nataleigh,Bellinger, Tania J.,Deese, Nichele,Guo, Fenghai,Harvin, Teavian,Hukins, Dabria T.,Pickens-Flynn, Ti'Bran,Tutein, Mai Ling C. Tang Yuk,Whitaker, Samuel H.
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- Hydrazone derivatives enhance antileishmanial activity of thiochroman-4-ones
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Cutaneous leishmaniasis (CL) is a neglected tropical disease, which causes severe skin lesions. Due to the lack of effective vaccines, and toxicity or reduced effectiveness of available drugs in addition to complex and prolonged treatments, there is an urgent need to develop alternatives for the treatment for CL with different mechanisms of action. In our effort to search for new promising hits against Leishmania parasites we prepared 18 acyl hydrazone derivatives of thiochroman-4-ones. Compounds were evaluated for their in vitro antileishmanial activity against the intracellular amastigote form of Leishmania panamensis and cytotoxic activity against human monocytes (U-937 ATCC CRL-1593.2). Our results show that derivatization of the thiochroman-4-ones with acyl hydrazones significantly enhances the antileishmanial activity. Among the compounds tested semicarbazone and thiosemicarbazone derivatives of thioflavanone 19 and 20 displayed the highest antileishmanial activities, with EC50 values of 5.4 and 5.1 μM and low cytotoxicities (100.2 and 50.1 μM respectively), resulting in higher indexes of selectivity (IS).
- Vargas, Esteban,Echeverri, Fernando,Upegui, Yulieth A.,Robledo, Sara M.,Qui?ones, Wiston
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- Development of conjugate addition of lithium dialkylcuprates to thiochromones: Synthesis of 2-alkylthiochroman-4-ones and additional synthetic applications
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Lithium dialkylcuprates undergo conjugate addition to thiochromones to afford 2-alkylthiochroman-4-ones in good yields. This approach provide an efficient and general synthetic approach to privileged sulfur-containing structural motifs and valuable precursors for many pharmaceuticals, starting from common substrates-thiochromones. Good yields of 2-alkyl-substituted thiochroman-4-ones are attained with lithium dialkylcuprates, lithium alkylcyanocuprates or substoichiometric amount of copper salts. The use of commercially available inexpensive alkyllithium reagents will expedite the synthesis of a large library of 2-alkyl substituted thiochroman-4-ones for additional synthetic applications.
- Bass, Shekinah A.,Parker, Dynasty M.,Bellinger, Tania J.,Eaton, Aireal S.,Dibble, Angelica S.,Koroma, Kaata L.,Sekyi, Sylvia A.,Pollard, David A.,Guo, Fenghai
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- COMPOUNDS FOR USE AS AN ANTI-BACTERIAL OR ANTI-FUNGAL AGENT AND AS A ZINC SENSOR
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The present invention relates to a compound, which can be used as an anti-bacterial and/or an anti-fungal agent as well as a zinc sensor. Moreover, the present invention relates to a pharmaceutical composition comprising said compound and methods for treating bacterial or fungal infections in mammals.
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Paragraph 0102; 0103; 0104
(2018/01/18)
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- Synthesis and evaluation of thiochroman-4-one derivatives as potential leishmanicidal agents
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The S-containing heterocyclic compounds benzothiopyrans or thiochromones stand out as having promising biological activities due to their structural relationship with chromones (benzopyrans), which are widely known as privileged scaffolds in medicinal chemistry. In this work, we report the synthesis of 35 thiochromone derivatives and the in vitro antileishmanial and cytotoxic activities. Compounds were tested against intracellular amastigotes of Leishmania panamensis and cytotoxic activity against human monocytes (U-937 ATCC CRL-1593.2). Compounds bearing a vinyl sulfone moiety, 4h, 4i, 4j, 4k, 4l and 4m, displayed the highest antileishmanial activity, with EC50 values lower than 10 μM and an index of selectivity over 100 for compounds 4j and 4l. When the double bond or the sulfone moiety was removed, the activity decreased. Our results show that thiochromones bearing a vinyl sulfone moiety are endowed with high antileishmanial activity and low cytotoxicity.
- Vargas, Esteban,Echeverri, Fernando,Vélez, Iván D.,Robledo, Sara M.,Qui?ones, Wiston
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- Rh-Catalyzed Conjugate Addition of Arylzinc Chlorides to Thiochromones: A Highly Enantioselective Pathway for Accessing Chiral Thioflavanones
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A highly efficient asymmetric synthesis of chiral thioflavanones is developed via conjugate addition of arylzinc reagents to thiochromones using Rh(COD)Cl2/(R)-3,4,5-MeO-MeOBIPHEP catalyst. This method overcomes catalyst poisoning and substrate inertness and affords a series of chiral thioflavanones (2-arylthiochroman-4-ones) in good yields (up to 91% yield) with excellent ee values (up to 97% ee). The established asymmetric synthesis paves the way for further pharmaceutical studies.
- Meng, Ling,Jin, Ming Yu,Wang, Jun
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supporting information
p. 4986 - 4989
(2016/10/14)
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- Superelectrophilic Activation of Crotonic/Methacrylic Acids: Direct Access to Thiochroman-4-ones from Benzenethiols by Microwave-Assisted One-Pot Alkylation/Cyclic Acylation
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An efficient microwave-assisted protocol for the synthesis of 2-/3-methylthiochroman-4-ones by superacid-catalyzed alkylation followed by cyclic acylation (cyclization via intramolecular acylation) is described. Using easily accessible benzenethiols and crotonic acid/methacrylic acid with triflic acid (as catalyst of choice for needed optimal acidity), the reaction was tuned toward the formation of the cyclized products in good selectivity and yield. A mechanism involving the formation of carbenium-carboxonium superelectrophilic species is suggested.
- Vaghoo, Habiba,Prakash, G. K. Surya,Narayanan, Arjun,Choudhary, Rohit,Paknia, Farzaneh,Mathew, Thomas,Olah, George A.
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p. 6170 - 6173
(2016/01/09)
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- Direct aromatic tert-butylation during the synthesis of thiochroman-4-ones
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The synthesis of thiochroman-4-ones from thiophenols and 3-methylbut-2-enoic acid effected by methane sulphonic acid is accompanied by tert-butylation of the aromatic ring. 3-Arylthiobutanoic acids, available using β-butyrolactone, are efficiently cyclised in the same manner.
- Clayton, Stephen E.,Gabbutt, Christopher D.,Hepworth, John D.,Mark Heron
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p. 939 - 946
(2007/10/02)
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- Therapeutic [1]benzothiopyrano[4,3-c]pyrazoles
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This invention relates to compounds of formula I wherein R1 represents hydrogen or together with R2 represents a bond; R2 together with either one of R1 and R3 represents a bond; R3 represe
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