- One-step novel synthesis of methylene bisphenols and methylene bisnaphthols using Lewis acid mediated rearrangement
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Mono- and di-substituted isomeric methylene bisphenols and methylene bisnaphthols have been synthesized by rearrangement of the corresponding O-methoxyacetyl derivatives of phenols and naphthols, respectively, in presence of aluminium chloride under dry conditions. The chemistry observed is different from the usual Fries rearrangement reaction and involves an intermolecular rearrangement. The reactions reported here also reflect the influence of substituents present in the substrate as is supported by the substitution of the bridging methylene at a position meta to the phenolic hydroxyl in some of the minor products formed along-side the majorly formed ortho substituted products.
- Kumar, Sandeep,Mehta, Shilpika Bali
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- Synthesis and antimicrobial activities of halogenated bis(hydroxyphenyl)methanes
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A series of halophenols was prepared by the reaction of bis(hydroxyphenyl)methanes with effective halogenating agents such as bromine and sulfuryl chloride. One of these compounds, a biologically active halophenol-2,2′,3,3′-tetrabromo-4,4′,5,5′-tetrahydroxydiphenylmethane (1)-frequently isolated from red algae, was synthesized for the first time. Other halophenols included several novel compounds, together with known derivatives that were synthesized from the phenolic intermediates, bis(3,4-dihydroxyphenyl)methane (5) and bis(2-hydroxyphenyl)methane (14). All of the synthesized compounds were tested for antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. The preliminary structure-activity relationship was investigated in order to determine the essential structural requirements for their antimicrobial activity. Of all these halophenols, 2,2′,3,3′,6-pentabromo-4,4′,5,5′-tetrahydroxydiphenylmethane (8) was found to be the most active against Candida albicans, Aspergillus fumigatus, Trichophyton rubrum, and Trichophyton mentagrophytes while 3,3′,5,5′-tetrachloro-2,2′-dihydroxydiphenylmethane (18) exerted a powerful antibacterial effect against Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Proteus vulgaris, and Salmonella typhimurium.
- Oh, Ki-Bong,Lee, Ji Hye,Lee, Jong Wook,Yoon, Kyung-Mi,Chung, Soon-Chun,Jeon, Heung Bae,Shin, Jongheon,Lee, Hyi-Seung
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scheme or table
p. 945 - 948
(2009/09/06)
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- Anticalculus composition
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This invention relates to an improved composition for inhibiting dental plaque and calculus formation, comprising zinc ions and a non-toxic, organoleptically acceptable antibacterial agent in an orally acceptable medium, and to a process for retarding the growth of dental plaque and calculus by application to the teeth of the above composition.
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