Synthesis of Polyfunctional Aromatic Ring Systems (Phloroglucide Analogs) under Microwave Irradiation

Khalafi‐Nezhad, Ali; Rad, Mohammad Navid Soltani; Hakimelahi, G. H.

doi:10.1002/hlca.200390192

Cited by 19 publications

(9 citation statements)

References 15 publications

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“…To an aqueous solution of NaOH (25%, 50 ml) containing p ‐chlorophenol (Moshfegh et al., 1982b; Khalafi‐Nezhad et al., 2003) (2.8 g, 0.1 mol) and methanol (25 ml) formalin (38%, 90 ml) was added. The reaction mixture was stirred at 60–80°C for 1 h and then was cooled to room temperature for 24 h. Then a mixture of water (50 ml) and acetic acid (15 ml) was added.…”

Section: Chemistrymentioning

confidence: 99%

“…However, due to availability of other effective drugs with known risk and contraindications, thus, the phenolic agents have not found a general therapeutic application and they are mostly used as disinfectants (Hugo and Russel, 1992;Gennaro, 1995). In recent decades, synthesis of the tri-and tetracycles and their roles as antimicrobial agents is in the focus of the pharmaceutical investigations (Moshfegh et al, 1990;Phan et al, 2001;Khalafi-Nezhad et al, 2003). The presence of essential functional groups in a suitable spatial arrangement for chelating metal ions of enzymes is a feature in some of the phenolic tri-or tetracycles that could be effective at the beginning of wound healing.…”

Section: Introductionmentioning

confidence: 99%

“…The presence of essential functional groups in a suitable spatial arrangement for chelating metal ions of enzymes is a feature in some of the phenolic tri‐ or tetracycles that could be effective at the beginning of wound healing. For this reason, several antibacterial phloroglucide analogues were synthesized in the Chemistry Department of Shiraz University (Moshfegh et al., 1982a,b,c; Khalafi‐Nezhad et al., 2003). Based on the above criteria, 4‐chloro‐2,6‐bis‐(2‐hydroxyl‐benzyl)‐phenol (CBHBP) was synthesized in this laboratory with a new method.…”

Section: Introductionmentioning

confidence: 99%

“…The mixture was transferred to a test tube and irradiated in the microwave oven for 40 s at 400 W. The crude products were suspended in boiling H 2 O to dissolve ZnC1 2 and unreacted phenols. The mixture was then filtered and the solid was purified using column chromatography on silica-gel, eluted with (EtOAc/n-hexane) (1:3) attained pure product 3 (0.67 g, 73%) (Khalafi-Nezhad et al, 2003).…”

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confidence: 99%

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Effects of 4‐chloro‐2,6‐bis‐(2‐hydroxyl‐benzyl)‐phenol on Healing of Skin Wounds and Growth of Bacteria

Oryan

Khalafi-Nezhad

Toloo

et al. 2007

Journal of Veterinary Medicine Series A

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In this investigation, the effects of synthesized 4-chloro-2,6-bis-(2-hydroxyl-benzyl)-phenol (CBHBP) on cutaneous wound healing and growth of some of the wound contaminating microorganisms were studied. The antibacterial effects of this compound were then evaluated on Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and Klebsiella spp., using solid dilution method. It was demonstrated that CBHBP has a significant antimicrobial activity against S. aureus but it is not effective in the case of other microorganisms studied in this experiment. The effect of local administration of CBHBP on healing of a standard full-thickness 2 cm skin incision of skeletally mature rats was evaluated. Histological changes together with mechanical properties and dry weight content of the healing tissues at the site of the lesions were assessed in treated and untreated animals. It was observed that the injured area of the treated animals was more organized and showed more fibroblasts and less inflammatory cells. Much better maturation criteria in treated tissues were observed in comparison with those of the untreated ones which contained numerous polymorphonuclear inflammatory cells after 14 days post-injury. Many infiltrated macrophages and lymphocytes were present even 28 days after injury induction in the haphazardly organized dermis and also in subcutaneous tissues of the untreated animals. The percentage dry weight content of the treated lesions at 14 days post-injury was remarkably higher than those of the untreated animals. The results of biomechanical tensile testing showed that the ultimate tensile strength and stress of the injured skin of the treated animals were higher than those of the untreated ones. From these results, it could be concluded that CBHBP can be effective on wound healing and may be considered as a treatment regimen after evaluating its mechanism of action as well as testing its contraindications.

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Section: Chemistrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of 4‐chloro‐2,6‐bis‐(2‐hydroxyl‐benzyl)‐phenol on Healing of Skin Wounds and Growth of Bacteria

Oryan

Khalafi-Nezhad

Toloo

et al. 2007

Journal of Veterinary Medicine Series A

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“…15 We also investigated the condensation of C3-substituted-2-naphthols and phenols with MW irradiation and found that the mixtures in acetonitrile at 150°C in the presence of potassium carbonate under MW irradiation conditions gave the desired products with good yields (eq 3). …”

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confidence: 99%

Iron-catalyzed Asymmetric Aerobic Oxidative Dearomatizing Spirocyclization of Methylenebis(arenol)s

Kim¹,

Oguma²,

Fujitomo³

et al. 2016

Chem. Lett.

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Iron-catalyzed asymmetric oxidative dearomatization of methylenebis(arenol)s, readily prepared from salicyl alcohol and naphthol derivatives under microwave irradiation, was developed using dioxygen in air as an oxidant. Various enantioenriched spirocyclic compounds were obtained with up to 89% chemical yield and 87% ee. Keywords: Asymmetric oxidation | Dearomatization | SpirocyclizationAsymmetric oxidative dearomatization is highly valuable and reliable tool for the construction of complicated ring structures in an enantioselective manner.1 To date, various catalytic methodologies such as oxidative DielsAlder reaction and oxidative nucleophilic dearomatization have been extensively developed and demonstrated to be highly efficient in the synthesis of natural products and chiral resources. In 2008, Kita and co-workers have achieved a significant breakthrough in this field by inducing the enantioselective oxidative dearomatizing intramolecular spirocyclization of phenol derivatives using a conformationally rigid chiral hypervalent iodine reagent as a stoichiometric oxidant or as a catalyst.2 Thereafter, Uyanik and Ishihara et al. reported a highly enantioselective catalytic Kita spirocyclization using a conformationally flexible C 2 -symmetric chiral iodoarene as a catalyst.3 Subsequent to these studies, several chiral hypervalent iodine compounds have been synthesized and the catalysis of asymmetric oxidative dearomatizing spirocyclization has been intensively studied. 4 However, most of these hypervalent iodine-catalyzed spirocyclizations use low atom-efficient meta-chloroperbenzoic acid as the terminal oxidant. Thus, highly atom-efficient and environmentally friendly methodologies for oxidative dearomatizing spirocyclization are strongly required.Very recently, Ishihara et al. have reported a reaction using highly atom-economic and environmentally friendly oxidants such as hydrogen peroxide as terminal oxidants with good to high enantioselectivity. 5 On the other hand, we also found that iron(salan) complexes are efficient catalysts for the asymmetric oxidative coupling of 2-naphthols and dearomatization of 1-alkyl-2-naphthols via nucleophilic addition of nitroalkanes (Scheme 1, eq 1), 6 and dearomatizing spirocyclization of 1-methyl-2-naphthols with phenol derivatives (Scheme 1, eq 2). 7Note that iron-catalyzed asymmetric dearomatizations can use dioxygen, which is the most abundant, ubiquitous and atomefficient oxidant, as a hydrogen accepter. On the basis of previous mechanistic studies, we propose that the oxidative spirocyclization proceeds via the following steps: (a) single electron transfer (SET) from 2-naphthols to molecular oxygen to afford a radical cationic species A, 9 (b) hydrogen atom abstraction (HAT) to generate an ortho-quinone methide (o-QM) B, (c) FriedelCrafts-type alkylation 10 followed by rearomatization to afford a methylenebis(arenol) C, and (d) a second intramolecular oxidative dearomatizationspirocyclization to afford D (Figure 1).11 Although this tandem o-QM formation/Michael addi...

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Iron‐Catalyzed Asymmetric Inter‐ and Intramolecular Aerobic Oxidative Dearomatizing Spirocyclization of 2‐Naphthols

et al. 2019

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Highly chemo‐ and enantioselective inter‐ and intra‐molecular oxidative dearomatizing spirocyclization of 1‐alkyl‐2‐naphthols with O2 as the hydrogen acceptor was achieved using an iron catalyst. In the iron complex 1‐catalyzed reaction, 1‐methyl‐2‐naphthols 2 in the presence of phenol derivatives as the nucleophile was selectively oxidized, producing the spirocyclic ketones with good to high enantioselectivities via a tandem strategy. Pre‐synthesized 1,1′‐methylbis(arenol)s 6 and 7, intermediates of the tandem strategy were also converted to the desired products with chemo‐ and enantioselectivity.

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Synthesis of Polyfunctional Aromatic Ring Systems (Phloroglucide Analogs) under Microwave Irradiation

Cited by 19 publications

References 15 publications

Effects of 4‐chloro‐2,6‐bis‐(2‐hydroxyl‐benzyl)‐phenol on Healing of Skin Wounds and Growth of Bacteria

Effects of 4‐chloro‐2,6‐bis‐(2‐hydroxyl‐benzyl)‐phenol on Healing of Skin Wounds and Growth of Bacteria

Iron-catalyzed Asymmetric Aerobic Oxidative Dearomatizing Spirocyclization of Methylenebis(arenol)s

Iron‐Catalyzed Asymmetric Inter‐ and Intramolecular Aerobic Oxidative Dearomatizing Spirocyclization of 2‐Naphthols

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