Reduction of o-hydroxyaromatic carboxylic acids through ethoxycarbonyl derivatives with sodium borohydride.

Minami, Norio; Kijima, Shizumasa

doi:10.1248/cpb.27.816

Cited by 20 publications

(11 citation statements)

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“…Although the two routes just described were already satisfactory, we eventually found a much more effective route to 1 based on the report by Minami and Kijima of the reduction of salicylic acids to the corresponding 2-methylphenols. [13] According to this method, the salicylic acid is converted upon reaction with ethyl chloroformate into a bis-ethoxycarbonyl derivative, whose treatment with sodium borohydride in aqueous THF directly affords the 2-methylphenol in moderate to good yields. The latter step is supposed to proceed through an initial reduction of the carboxylic site of the mixed anhydride moiety to the corresponding benzyloxy anion, followed by migration of the residual carbonate group from the phenolic to the alcoholic oxygen atom.…”

Section: Resultsmentioning

confidence: 99%

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D₃)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D₃‐α‐Tocopherol

et al. 2004

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Different routes are described for the synthesis of 4‐benzyloxy‐2‐D3‐phenol, a key building block in the preparation of D3‐δ‐tocopherol. Conditions for the improvement of Minami’s reduction are also given, allowing a straightforward route to the title compound and a new synthesis of R,R,R‐5‐D3‐α‐tocopherol in good yields, starting from widely available R,R,R‐α‐tocopherol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Section: Resultsmentioning

confidence: 99%

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D₃)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D₃‐α‐Tocopherol

et al. 2004

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“…The preparation procedure and spectroscopic data for substrates 2b – 2d , 2g are described below. 1-Methyl-2-hydroxy naphthalene 15 is also known and was prepared from 2-naphthol.…”

Section: Methodsmentioning

confidence: 99%

Visible Light and Hydroxynaphthylbenzimidazoline Promoted Transition-Metal-Catalyst-Free Desulfonylation of N-Sulfonylamides and N-Sulfonylamines

et al. 2018

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A visible light promoted process for desulfonylation of N-sulfonylamides and -amines has been developed, in which 1,3-dimethyl-2-hydroxynaphthylbenzimidazoline (HONap-BIH) serves as a light absorbing, electron and hydrogen atom donor, and a household white light-emitting diode serves as a light source. The process transforms various N-sulfonylamide and -amine substrates to desulfonylated products in moderate to excellent yields. The observation that the fluorescence of 1-methyl-2-naphthoxy anion is efficiently quenched by the substrates suggests that the mechanism for the photoinduced desulfonylation reaction begins with photoexcitation of the naphthoxide chromophore in HONap-BIH, which generates an excited species via intramolecular proton transfer between the HONap and BIH moieties. This process triggers single electron transfer to the substrate, which promotes loss of the sulfonyl group to form the free amide or amine. The results of studies employing radical probe substrates as well as DFT calculations suggest that selective nitrogen-sulfur bond cleavage of the substrate radical anion generates either a pair of an amide or amine anion and a sulfonyl radical or that of an amidyl or aminyl radical and sulfinate anion, depending on the nature of the N-substituent on the substrate. An intermolecular version of this protocol, in which 1-methyl-2-naphthol and 1,3-dimethyl-2-phenylbenzimidazoline are used concomitantly, was also examined.

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“…For the synthesis of the designed alkynyloxy-substituted xanthones 1a and 2a (Scheme ), 4-methoxy-2-methylphenol, obtained from the reduction of 2-hydroxy-5-methoxybenzaldehyde, or the commercially available 3-methoxy-5-methylphenol was reacted with 2-chlorobenzoic acid under Ullmann reaction conditions to give the corresponding diarylethers, which were then cyclized by treatment with polyphosphoric acid to obtain the xanthone cores ( 4 , 7 ). Bromination of the methyl group with NBS and subsequent reaction with imidazole allowed obtaining the intermediates 5 and 8 , which were then demethylated with AlCl 3 to give the corresponding hydroxyl derivatives 6 and 9 and successively alkylated with 1-bromo-2-pentyne to get the final compounds.…”

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confidence: 99%

Targeting Orthosteric and Allosteric Pockets of Aromatase via Dual-Mode Novel Azole Inhibitors

Caciolla

Spinello

Martini

et al. 2020

ACS Med. Chem. Lett.

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Breast cancer (BC) is the most diffused cancer type in women and the second leading cause of death among the female population. Effective strategies to fight estrogen responsive (ER+) BC, which represents 70% of all BC cases, rely on estrogen deprivation, via the inhibition of the aromatase enzyme, or the modulation of its cognate estrogen receptor. Current clinical therapies significantly increased patient survival time. Nevertheless, the onset of resistance in metastatic BC patients undergoing prolonged treatments is becoming a current clinical challenge, urgently demanding to devise innovative strategies. In this context, here we designed, synthesized, and performed in vitro inhibitory tests on the aromatase enzyme and distinct ER+/ER– BC cell line types of novel azole bridged xanthones. These compounds are active in the low μM range and behave as dual-mode inhibitors, targeting both the orthosteric and the allosteric sites of the enzyme placed along one access channel. Classical and quantum-classical molecular dynamics simulations of the new compounds, as compared with selected steroidal and nonsteroidal inhibitors, provide a rationale to the observed inhibitory potency and supply the guidelines to boost the activity of inhibitors able to exploit coordination to iron and occupation of the access channel to modulate estrogen production.

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Reduction of o-hydroxyaromatic carboxylic acids through ethoxycarbonyl derivatives with sodium borohydride.

Cited by 20 publications

References 0 publications

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D₃)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D₃‐α‐Tocopherol

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D₃)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D₃‐α‐Tocopherol

Visible Light and Hydroxynaphthylbenzimidazoline Promoted Transition-Metal-Catalyst-Free Desulfonylation of N-Sulfonylamides and N-Sulfonylamines

Targeting Orthosteric and Allosteric Pockets of Aromatase via Dual-Mode Novel Azole Inhibitors

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Reduction of o-hydroxyaromatic carboxylic acids through ethoxycarbonyl derivatives with sodium borohydride.

Cited by 20 publications

References 0 publications

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D3)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D3‐α‐Tocopherol

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D3)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D3‐α‐Tocopherol

Visible Light and Hydroxynaphthylbenzimidazoline Promoted Transition-Metal-Catalyst-Free Desulfonylation of N-Sulfonylamides and N-Sulfonylamines

Targeting Orthosteric and Allosteric Pockets of Aromatase via Dual-Mode Novel Azole Inhibitors

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Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D₃)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D₃‐α‐Tocopherol

Approaches to the Preparation of 4‐Benzyloxy‐2‐(α,α,α‐D₃)methylphenol, a Building Block for Labeled δ‐Tocopherol, and a New Synthesis ofR,R,R‐5‐D₃‐α‐Tocopherol