- Structure-Odor Activity Studies on Derivatives of Aromatic and Oxygenated Monoterpenoids Synthesized by Modifying p-Cymene
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Thymoquinone was recently reported as having a unique pencil-like odor and being the impact compound for the cedar-like and cedar wood-based product smell such as pencils. The compounds thymol and carvacrol are structurally related odorants commonly found in plants and foods such as thyme and oregano, also having a significant contribution to their overall aroma. However, a systematic elucidation of the sensory properties in this class of oxygenated, aromatic monoterpenoids has not been carried out. To close this gap and gain new insights into structure-odor relationships leading to pencil-like and woody odors, 19 structurally related derivatives of p-cymene starting from thymol and carvacrol were synthesized and characterized. The compounds had odor thresholds ranging from 2.0 ng/L air to 388.8 ng/L air, being lowest for thymol and carvacrol and highest for thymohydroquinone. The compounds smelled mostly thyme-like, oregano-like, and pencil-like with phenolic, earthy, and medicinal variations in their odor character, which could be successfully linked to structural motifs.
- Schreiner, Linda,Bauer, Johannes,Ortner, Eva,Buettner, Andrea
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supporting information
p. 834 - 842
(2020/03/30)
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- 4,5-Dimethyl-2-Iodoxybenzenesulfonic Acid Catalyzed Site-Selective Oxidation of 2-Substituted Phenols to 1,2-Quinols
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A site-selective hydroxylative dearomatization of 2-substituted phenols to either 1,2-benzoquinols or their cyclodimers, catalyzed by 4,5-dimethyl-2-iodoxybenzenesulfonic acid with Oxone, has been developed. Natural products such as biscarvacrol and lacinilene C methyl ether could be synthesized efficiently under mild reaction conditions. Furthermore, both the reaction rate and site selectivity could be further improved by the introduction of a trialkylsilylmethyl substituent at the 2-position of phenols. The corresponding 1,2-quinols could be transformed into various useful structural motifs by [4+2] cycloaddition cascade reactions.
- Uyanik, Muhammet,Mutsuga, Tatsuya,Ishihara, Kazuaki
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supporting information
p. 3956 - 3960
(2017/03/27)
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- A Catalyst-Controlled Aerobic Coupling of ortho-Quinones and Phenols Applied to the Synthesis of Aryl Ethers
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ortho-Quinones are underutilized six-carbon-atom building blocks. We herein describe an approach for controlling their reactivity with copper that gives rise to a catalytic aerobic cross-coupling with phenols. The resulting aryl ethers are generated in high yield across a broad substrate scope under mild conditions. This method represents a unique example where the covalent modification of an ortho-quinone is catalyzed by a transition metal, creating new opportunities for their utilization in synthesis.
- Huang, Zheng,Lumb, Jean-Philip
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supporting information
p. 11543 - 11547
(2016/11/17)
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- The formation of orthoquinones in the dimethyldioxirane oxidation of phenols
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The dimethyldioxirane oxidation of selected phenols provides the corresponding orthoquinones. This conversion proceeds via the related arenediols, which are cleanly oxidized to the quinones by this oxidant.
- Crandall, Jack K.,Zucco, Martine,Scott Kirsch,Coppert, David M.
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p. 5441 - 5444
(2007/10/02)
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- COMPARATIVE OXIDATION OF PHENOLS WITH BENZENESELENINIC ANHYDRIDE AND WITH BENZENESELENINIC ACID
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Oxidation of phenols by benzeneseleninic acid 2 in methylene dichloride leads to the para-quinones, whereas oxidation by benzeneseleninic anhydride 1 is confirmed to afford the corresponding ortho-quinones.Addition of indole, as a phenylselenium (II) trapping agent, inhibits the formation of phenylselenoquinones in the oxidation with 1 or 2.
- Barton, Derek H. R.,Finet, Jean-Pierre,Thomas, Martial
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p. 6397 - 6406
(2007/10/02)
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- Oxidation of Phenols, Pyrocatechols, and Hydroquinones to ortho-Quinones using Benzeneseleninic Anhydride
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Benzeneseleninic anhydride has been used as a mild oxidising reagent to convert phenols into o-quinones including some examples where the p-position is unblocked.The method is limited to the production of o-quinones which are not susceptible to futher reaction.Pyrocatechols and hydroquinones can also be oxidised to the corresponding quinones in excellent yield using benzeneseleninic anhydride.
- Barton, Derek H. R.,Brewster, Andrew G.,Ley, Steven V.,Read, Christine M.,Rosenfeld, Moshe N.
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p. 1473 - 1476
(2007/10/02)
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