- Pd-Catalyzed ipso, meta-Dimethylation of ortho-Substituted Iodoarenes via a Base-Controlled C-H Activation Cascade with Dimethyl Carbonate as the Methyl Source
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A methyl group can have a profound impact on the pharmacological properties of organic molecules. Hence, developing methylation methods and methylating reagents is essential in medicinal chemistry. We report a palladium-catalyzed dimethylation reaction of ortho-substituted iodoarenes using dimethyl carbonate as a methyl source. In the presence of K2CO3 as a base, iodoarenes are dimethylated at the ipso- and meta-positions of the iodo group, which represents a novel strategy for meta-C-H methylation. With KOAc as the base, subsequent oxidative C(sp3)-H/C(sp3)-H coupling occurs; in this case, the overall transformation achieves triple C-H activation to form three new C-C bonds. These reactions allow expedient access to 2,6-dimethylated phenols, 2,3-dihydrobenzofurans, and indanes, which are ubiquitous structural motifs and essential synthetic intermediates of biologically and pharmacologically active compounds.
- Wu, Zhuo,Wei, Feng,Wan, Bin,Zhang, Yanghui
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p. 4524 - 4530
(2021/05/04)
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- Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum
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The volatiles emitted by the ascomycetes Hypoxylon griseobrunneum and Hypoxylon macrocarpum (Hypoxylaceae, Xylariales) were collected by use of a closed-loop stripping apparatus (CLSA) and analysed by GC-MS. The main compound class of both species were polysubstituted benzene derivatives. Their structures could only be unambiguously determined by comparison to all isomers with different substitution patterns. The substitution pattern of the main compound from H. griseobrunneum, the new natural product 2,4,5-trimethylanisole, was explainable by a polyketide biosynthesis mechanism that was supported by a feeding experiment with (methyl-2H3)methionine.
- Rinkel, Jan,Babczyk, Alexander,Wang, Tao,Stadler, Marc,Dickschat, Jeroen S.
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p. 2974 - 2990
(2019/01/05)
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- Design, Conformation, and Crystallography of 2-Naphthyl Phenyl Ethers as Potent Anti-HIV Agents
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Catechol diethers that incorporate a 7-cyano-2-naphthyl substituent are reported as non-nucleoside inhibitors of HIV-1 reverse transcriptase (NNRTIs). Many of the compounds have 1-10 nM potencies toward wild-type HIV-1. An interesting conformational effect allows two unique conformers for the naphthyl group in complexes with HIV-RT. X-ray crystal structures for 4a and 4f illustrate the alternatives.
- Lee, Won-Gil,Chan, Albert H.,Spasov, Krasimir A.,Anderson, Karen S.,Jorgensen, William L.
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supporting information
p. 1156 - 1160
(2016/12/16)
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- Methylation of phenol and its derivatives with dimethyl carbonate in the presence of Mn2(CO)10, W(CO)6, and Co2(CO)8
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Aryl methyl ethers were synthesized by reactions of phenol, substituted phenols, and α- and β-naphthols with dimethyl carbonate in the presence of manganese, tungsten, and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of aryl methyl ethers.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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p. 330 - 334
(2015/05/04)
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- Substituted Sulfonamide Compounds
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Substituted sulfonamide compounds corresponding to the formula I wherein m, n, p, Q, R1, R2, R3, R4, X, Y and Z have the respective meanings defined herein, pharmaceutical compositions containing such compounds, a process for their preparation, and the use of such compounds for the treatment and/or inhibition of pain and other conditions mediated by bradykinin receptor 1 (B1R) and/or bradykinin receptor 2 (B2R).
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Page/Page column 26
(2009/07/25)
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- Tetrahydroindenoindole compounds useful in the treatment of conditions associated with free radical formation
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The invention concerns compounds and their enantiomers of the formula IA or IB STR1 and pharmaceutically acceptable salts thereof wherein each of R1, R2, R3, R4, R6, R7, R8, R9, R10, R11 and R12 is independently selected from hydrogen or an alkyl group containing 1-6 carbon atoms and R5 is an alkoxy group containing 1-6 carbon atoms. The invention further concerns pharmaceutical compositions comprising the active compounds and methods employing the compounds for the treatment of conditions associated with free radical formation.
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- Indenoindole compounds
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Cis-fused compounds of the formula I wherein R is methoxy or ethoxy, when R is methoxy, R1 is methyl and R2 and R3 are both hydrogen or both methyl, and when R is ethoxy, R1 is hydrogen and R2 and R3 are both methyl, and enantiomers and salts thereof are
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- REACTION OF 1,2,4-TRIMETHYLBENZENE WITH PERACETIC ACID
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The oxidation of 1,2,4-trimethylbenzene with peracetic acid leads to the formation of trimethylphenols and hydroquinones, which undergo transformations to the corresponding benzoquinones and products from oxidative cleavage of the ring.The controlling stage of the process is the electrophilic hydroxylation of 1,2,4-trimethylbenzene.
- Kharchuk, V. G.,Kolenko, I. P.,Petrov, L. A.,Gus'kova, L. M.
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p. 2071 - 2078
(2007/10/02)
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- Synthesis of Substituted Dibenzophospholes. Part 2. Syntheses of Intermediate Biphenyls and Quaterphenyls
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A general procedure for synthesis of 4",6'-dialkoxy-2',2"-diamino-m-quaterphenyls has been established.Copper(I) t-butoxide is used to prepare 2,6-dinitrophenyls from 1,3-dinitrobenzene and aryl iodides.One of the nitro-groups is then exchanged for a methoxy-group by sodium methoxide in hexamethylohosphoramide; the resulting 2-methoxy-6-nitrobiphenyls are then iodinated in the 5-position.Ullmann coupling then gives the dinitroquaterphenyls which are reduced to the diamines.An alternative route from 2,2',4,4'-tetranitrobiphenyl was explored; arylation was easy but alkoxydenitration was indiscriminate.Some 71 new derivatives of biphenyl, terphenyl, and quterphenyl are reported.
- Cornforth, John,Sierakowski, Andrew F.,Wallace Timothy W.
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p. 2299 - 2316
(2007/10/02)
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