Reactivity of new precursors of quinone methides

Loubinoux, B.; Miazimbakana, Joseph; Gérardin, Philippe

doi:10.1016/s0040-4039(00)99619-9

Cited by 40 publications

(22 citation statements)

References 6 publications

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“…This confirms results already obtained with model reagents (Loubinoux et al 1989). This occurred at both 25 °C and 45 °C with the wood but with the cellulose only at 45 °C.…”

Section: Resultssupporting

confidence: 92%

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Short Note

1992

Holzforschung

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“…This confirms results already obtained with model reagents (Loubinoux et al 1989). This occurred at both 25 °C and 45 °C with the wood but with the cellulose only at 45 °C.…”

Section: Resultssupporting

confidence: 92%

“…Certain phenols are converted under mild conditions to quinone methides which react with diverse nucleophiles (Loubinoux et al 1989). Certain phenols are converted under mild conditions to quinone methides which react with diverse nucleophiles (Loubinoux et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Short Note

1992

Holzforschung

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“…The formation of 13a and 13b has been interpreted as proceeding via the electrocyclization of the intermediate ortho-quinone methide with the a-double bond as shown in structure 14 of Scheme 5 (37,38). Alkylation of ortho-quinone methides ortho-Quinone methide is known to react not only as heterodiene in the Diels-Alder reaction but also as a Michael acceptor (5,17,19). Previously we reported the reaction of 2-phenyl-1,3,2-benzodioxaborins with an alcohol, an alkylthiol, or tert-butylamine borane in the presence of a Lewis acid or protic acid to give the corresponding 2-substituted phenols (2 1).…”

Section: Synthesis Of Cannabinoidsmentioning

confidence: 99%

“…Intramolecular trapping of these quinone methides by otherwise unreactive dienophiles has also been documented (12)(13)(14)(15)(16)(17)(18). In the presence of nucleophiles, ortho-quinone methides generated in situ undergo Michael addition to give ortho-substituted phenols (5,17,19).…”

Section: Introductionmentioning

confidence: 98%

Reactions of 2-phenyl-4H-1,3,2-benzodioxaborin, a stable ortho-quinone methide precursor

Chambers¹,

Crawford²,

Williams³

et al. 1992

Can. J. Chem.

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Thermolysis of 1-phenyl-4H-1,3,2-benzodioxaborins generated the corresponding ortho-quinone methides, which were found to undergo intermolecular cycloaddition reactions with ethyl vinyl ether, dihydropyran, p-methylstyrene, cyclohexene, and 1-ethoxy-1-z-trimethylsiloxy-1-propenes to give various substituted chromans. Intramolecular trapping of the quinone methides with an olefin led to the syntheses of several analogs of tetrahydrocannabinols. ortho-Quinone methides, generated by treatment of the 2-phenyl-4H-1,3,2-benzodioxaborins with a Lewis acid, react with various nucleophiles to give the corresponding 1,4-addition products. Thus, alkyl and aryl thiols, alcohols, amine, hydride, ally1 trimethylsilane, acetophenone, and diethylmalonate as well as some aryl compounds react with the quinone methide to give various 2-substituted phenols. Intramolecular reaction of the quinone methide with an aryl group led to the preparation of some 4-phenylchromans and tetralins. La thermolyse des 2-phknyl-4H-1,3,2-benzodioxaborines conduit aux ortho-quinomkthanes correspondantes qui subissent des rkactions de cycloaddition interrnolkculaires avec l'ethoxykthkne, le dihydropyrane, le p-mkthylstyrkne, le cyclohexkne et les 1 -6thoxy-1 -z-trimkthylsiloxyprop-1 -knes pour conduire a divers chromanes substituks. Le pikgeage intrarnolkculaire des quinomkthanes avec une olefine permet la synthkse de plusieurs analogues des tktrahydrocannabinols. Les ortho-quinomkthanes, prCparCs par traitement des 2-phknyl-4H-1,3,2-benzodioxaborines avec un acide de Lewis, rkagissent avec divers nuclkophiles pour donner les produits d'additions-1,4 correspondants. Ainsi, les alkyl-et aryl-thiols, les alcools, les amines, les hydrures, l'allyltrim~thylsilane, I'acCtophknone et le malonate d'kthyle ainsi que certains composks aromatiques rkagissent avec le quinomkthane pour conduire a divers phknols substituks en position 2. La reaction intramolCculaire des quinomkthanes avec un groupe aryle conduit a la prkparation de quelques 4-phknylchromanes et de tktralines.[Traduit par la rkdaction]

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“…Through bioassay-guided separation, three new 8-9Ј linked neolignans, 1 (0.0048% from the dried rhizomes), 2 (0.0011%), and 3 (0.0010%), and a sesquineolignan, 4 (0.0015%), were isolated together with 10 known constituents, 1ЈS-1Ј-acetoxychavicol acetate 11) (5, 1.10%), 1ЈS-1Ј-acetoxyeugenol acetate 11) (6, 0.038%), 1ЈS-1Ј-hydroxychavicol acetate 12) (7, 0.048%), chavicol b-D-glucopyranoside 13) (8, 0.023%), methyleugenol 14) (9, 0.0006%), transp-hydroxycinnamaldehyde 15) (10, 0.028%), trans-p-coumaryl alcohol 16) (11, 0.052%), trans-p-hydroxycinnamyl acetate 17) (12, 0.021%), trans-p-coumaryl diacetate 11) (13, 0.015%), and p-hydroxybenzaldehyde 14) (14, 0.0047%). Structure of Galanganal (1) Galanganal (1) was isolated as a white powder.…”

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confidence: 99%

Inhibitors of Nitric Oxide Production from the Rhizomes of Alpinia galanga: Structures of New 8-9' Linked Neolignans and Sesquineolignan

et al. 2005

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The 80% aqueous acetone extract from the rhizomes of Alpinia galanga showed nitric oxide (NO) production inhibitory activities in mouse peritoneal macrophages. From the aqueous acetone extract, three new 8-9 linked neolignans, galanganal, galanganols A and B, and a sesquineolignan, galanganol C, were isolated together with nine known phenylpropanoids and p-hydroxybenzaldehyde. The structures of new neolignans were determined on the basis of physicochemical and chemical evidence. In addition, the inhibitory effects of the constituents from the rhizomes of A. galanga on NO production induced by lipopolysaccharide in mouse peritoneal macrophages were examined. Among them, galanganal (IC 50 ‫86؍‬ m mM), galanganols B (88 m mM) and C (33 m mM), 1S-1-acetoxychavicol acetate (2.3 m mM), 1S-1-acetoxyeugenol acetate (11 m mM), trans-p-hydroxycinnamaldehyde (ca. 20 m mM), trans-p-coumaryl alcohol (72 m mM), and trans-p-coumaryl diacetate (19 m mM) were found to show inhibitory activity.

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Reactivity of new precursors of quinone methides

Cited by 40 publications

References 6 publications

Short Note

Short Note

Reactions of 2-phenyl-4H-1,3,2-benzodioxaborin, a stable ortho-quinone methide precursor

Inhibitors of Nitric Oxide Production from the Rhizomes of Alpinia galanga: Structures of New 8-9' Linked Neolignans and Sesquineolignan

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