471-90-9Relevant articles and documents
Synthesis of chlorins and bacteriochlorins from cycloaddition reactions with porphyrins
Cavaleiro, José A. S.,Monteiro, Carlos J. P.,Moura, Nuno M. M.,P. M. S. Neves, M. Gra?a,Tomé, Augusto C.
, (2022/02/10)
Chlorins and bacteriochlorins are reduced porphyrin-type derivatives displaying characteristic structural, physical, and chemical features. Such features make chlorins and bacteriochlorins key “players” in several fields, and specifically in medicine as p
PROCESS FOR MANUFACTURING A SUBSTITUTED CYCLOHEXANECARBONITRILE
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Page/Page column 10, (2021/03/19)
A process for manufacturing a substituted cyclohexanecarbonitrile said process comprising the following steps: - reacting the corresponding substituted cyclohexanecarboxylic acid with thionyl chloride to make the corresponding acyl chloride; and simultaneously or subsequently - reacting the chloride with sulfonamide in sulfolane as solvent to make the substituted cyclohexanecarbonitrile.
Synthesis of three putative kairomones of the beech leaf-mining weevil Orchestes fagi (L.)
Mayo,Silk,Abeysekera,MaGee
supporting information, p. 1124 - 1132 (2016/07/21)
The beech leaf-mining weevil, Orchestes fagi (L.), also known as the beech flea weevil, is a common and widespread pest of beech, Fagus sylvatica L., in its native Europe. It now appears to be well established in Nova Scotia, Canada. We report a novel synthesis of 9-geranyl-p-cymene and syntheses of 9-geranyl-α-terpinene and 1,1-dimethyl-3-methylene-2-vinylcyclohexane, making partial use of known methods. All three of these compounds are found in beech leaf volatiles and/or wood and are putative kairomones of the beech leaf-mining weevil.
β-Carotene autoxidation: Oxygen copolymerization, non-vitamin A products, and immunological activity
Burton, Graham W.,Daroszewski, Janusz,Nickerson, James G.,Johnston, James B.,Mogg, Trevor J.,Nikiforov, Grigory B.
supporting information, p. 305 - 316 (2014/05/06)
Carotenoids are reported to have immunological effects independent of vitamin A activity. Although antioxidant activity has been suggested as a basis of action, the ability of carotenoids to autoxidize to numerous non-vitamin A products with immunological activity is an alternative yet to be fully explored. We have undertaken a systematic study of β-carotene autoxidation and tested the product mixture for immunological activity. Autoxidation proceeds predominantly by oxygen copolymerization, leading to a defined, reproducible product corresponding to net uptake of almost 8 molar equivalents of oxygen. The product, termed OxC-beta, empirical formula C40H60O 15 versus C40H56 for β-carotene, contains more than 30% oxygen (w/w) and 85% β-carotene oxygen copolymers (w/w) as well as minor amounts of many C8-C18 norisoprenoid compounds. No vitamin A or higher molecular weight norisoprenoids are present. The predominance of polymeric products has not been reported previously. The polymer appears to be a less polymerized form of sporopollenin, a biopolymer found in exines of spores and pollen. Autoxidations of lycopene and canthaxanthin show a similar predominance of polymeric products. OxC-beta exhibits immunological activity in a PCR gene expression array, indicating that carotenoid oxidation produces non-vitamin A products with immunomodulatory potential.
Syntheses of the enantiomers of γ-cyclogeranic acid, γ-cyclocitral, and γ-damascone: Enantioselective protonation of enolates
Fehr,Galindo
, p. 539 - 552 (2007/10/02)
(R)- and (S)-γ-cyclogeranic acid ((R)- and (S)-9, resp.) were obtained by resolution of the racemate, and their absolute configurations determined by chemical correlation. The γ-acids (R)- and (S)-9 were converted into (R)- and (S)-methyl γ-cyclogeranate ((R)- and (S)-6, resp.), and (R)- and (S)-γ-damascone ((R)- and (S)-5, resp.). A more direct entry to (R)- and (S)-9 consisted in the enantioselective protonation of a thiol ester enolate with (-)- or (+)-N-isopropylephedrine ((-)- or (+)-20) and subsequent hydrolysis of the (R)- and (S)-S-phenyl γ-thiocyclogeranate ((R)- and (S)-24, resp.; 97% ee). The esters (R)- and (S)-24 were also used as precursors of (R)- and (S)-γ-damascone ((R)- and (S)-5, resp.). Alternatively, (S)-5 (75% ee) was obtained by enantioselective protonation of ketone enolate 29 with (-)-N- isopropylephedrine ((-)-20). Organoleptic evaluation demonstrated that the (S)-enantiomers of methyl γ-cyclogeranate and γ-damascone are markedly superior to their (R)-enantiomers.
HETEROCUMULENES IN ACYLATION REACTIONS. 1. MECHANISM OF ACID HYDROLYSIS OF 2,6,6-TRIMETHYL-1-CARBONYLCYCLOHEX-2-ENE AND ITS THIO AND N-ISOPROPYLIMINO ANALOGS
Lyashchuk, S. N.,Skrypnik, Yu. G.,Bezrodnyi, B. P.
, p. 109 - 114 (2007/10/02)
It was established that γ-protonation of the substrate takes place preferentially during the acid hydrolysis of 2,6,6-trimethyl-1-carbonylcyclohex-2-ene and its thio and N-isopropylimino analogs.The contribution from γ-protonation increases with increase in the polarity of the medium, the activity of H+, and the electronegativity of the heteroatom.The experimental results were confirmed by theoretical calculations (MNDO).
Hydration Reactivity of Persistent Conjugated Ketenes
Allen, Annette D.,Stevenson, Andrew,Tidwell, Thomas T.
, p. 2843 - 2848 (2007/10/02)
The acid, neutral, and base hydrations of the crowded alkenylketene 1 and the arylketenes i-PrCPh=C=O (2) and t-BuCPh=C=O (3) have been measured, together with solvent isotope effects and general acid catalysis of the hydration of 1.The arylketenes 2 and 3 are the first for which acid-catalyzed hydration has been demonstrated.These ketenes show significantly lower reactivity than simple ketenes, and this is interpreted as the result of both steric and electronic factors operating in mechanisms involving rate-limiting proton transfer to carbon (the γ-carbon in 1) for the acid-catalyzed reaction, while both the neutral and hydroxide-induced reactions involve rate-limiting nucleophilic attack in the plane of the ketene on the carbonyl carbon.
Condensation of β-Cyclocitral with Benzaldehyde
Frank, Arlen W.
, p. 549 - 554 (2007/10/02)
β-Cyclocitral 1b condenses with benzaldehyde in the presence of base catalysts giving the 2-benzopyrans 4, 5 and 6, and in the presence of acid catalysts giving exclusively the aldehyde 7.The cyclocitrals 1a and 1b are both isomerized by strong base anion exchange resin, but their aldehyde-protected derivatives 2 and 3 are not.Some tests used to characterize the aldehydes and their condensation products are described.
