cas 579-60-2, O-EUGENOL | Articles data

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Subsupercritical Water Generated by Inductive Heating Inside Flow Reactors Facilitates the Claisen Rearrangement
Claisen rearrangement of electron-deficient O-allylated phenols, including fluorine-modified phenols, is facilitated in aqueous media at high temperatures and pressures under flow conditions, as opposed to organic solvents. The O-allylation of phenols can be coupled with the Claisen rearrangement in an integrated flow system.
Oltmanns, Mona,Kirschning, Andreas
supporting information
p. 1942 - 1946
(2020/11/13)

Synthesis and First-Time Assessment of o-Eugenol Derivatives against Mycobacterium tuberculosis
In this work, we report the first-time assessment of o-eugenol, 6-allyl-2-methoxyphenol, and their selected derivatives, against Mycobacterium tuberculosis H37RV, using the MABA susceptibility test. The bromo, nitro, O-alkylated, and reduced derivatives were obtained by standard methods and were characterized by spectroscopic and mass spectral data. Structure–activity relationships were investigated, with the most active derivatives being 4,5-dibromo-2-methoxy-6-propylphenol (139 μM) and 2-methoxy-3-nitro-6-propylphenol (237 μM). This study provides important information on the rational design of new lead anti-TB drugs based on o-eugenol derivatives.
Moraes, Adriana Marques,da Silva, Emerson Teixeira,Wardell, James L.,de Souza, Marcus V. N.
p. 633 - 638
(2020/07/30)

Semisynthetic Phenol Derivatives Obtained from Natural Phenols: Antimicrobial Activity and Molecular Properties
Semisynthetic phenol derivatives were obtained from the natural phenols: thymol, carvacrol, eugenol, and guaiacol through catalytic oxychlorination, Williamson synthesis, and aromatic Claisen rearrangement. The compounds characterization was carried out by 1H NMR, 13C NMR, and mass spectrometry. The natural phenols and their semisynthetic derivatives were tested for their antimicrobial activity against the bacteria: Staphylococcus aureus, Escherichia coli, Listeria innocua, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Salmonella enterica ssp. enterica, and Bacillus cereus. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were determined using concentrations from 220 to 3.44 μg mL-1. Most of the tested compounds presented MIC values ≤220 μg mL-1 for all the bacteria used in the assays. The molecular properties of the compounds were computed with the PM6 method. Through principle components analysis, the natural phenols and their semisynthetic derivatives with higher antimicrobial potential were grouped.
Pinheiro, Patrícia Fontes,Menini, Luciana Alves Parreira,Bernardes, Patrícia Campos,Saraiva, Sérgio Henriques,Carneiro, José Walkimar Mesquita,Costa, Adilson Vidal,Arruda, Társila Rodrigues,Lage, Mateus Ribeiro,Gon?alves, Patrícia Martins,Bernardes, Carolina De Oliveira,Alvarenga, Elson Santiago,Menini, Luciano
p. 323 - 330
(2018/01/17)

Palladium-Catalyzed Fluoroalkylative Cyclization of Olefins
A palladium-catalyzed fluoroalkylative cyclization of olefins with readily available Rf-I reagents to afford the corresponding fluoroalkylated 2,3-dihydrobenzofuran and indolin derivatives with moderate to excellent yields is reported. This novel procedure provides an efficient method for the construction of Csp3-CF2 and C-O/N bonds in one step. A wide range of functional groups are tolerated. It is proposed that a radical/SET (single electron transfer) pathway proceeding via the fluoroalkyl radical may be involved in the catalytic cycle.
Liao, Jianhua,Fan, Lianfeng,Guo, Wei,Zhang, Zhenming,Li, Jiawei,Zhu, Chuanle,Ren, Yanwei,Wu, Wanqing,Jiang, Huanfeng
supporting information
p. 1008 - 1011
(2017/03/15)

Boosting effect of ortho-propenyl substituent on the antioxidant activity of natural phenols
Seven new antioxidants derived from natural or synthetic phenols have been designed as alternatives to BHT and BHA antioxidants. Influence of various substituents at the ortho, meta and para positions of the aromatic core of phenols on the bond dissociation enthalpy of the ArO-H bond was evaluated using a DFT method B3LYP/6-311++G(2d,2p)//B3LYP/6-311G(d,p). This prediction highlighted the ortho-propenyl group as the best substituent to decrease the bond dissociation enthalpy (BDE) value. The rate constants of hydrogen transfer from these phenols to DPPH radical in a non-polar and non-protic solvent have been measured and were found to be in agreement with the BDE calculations. For o-propenyl derivatives from 2-tert-butyl-4-methylphenol, BHA, creosol, isoeugenol and di-o-propenyl p-cresol, fewer radicals were trapped by a single phenol molecule, i.e. a lower stoichiometric number. Reaction mechanisms involving the evolution of the primary phenoxyl radical ArO are proposed to rationalise these effects.
Marteau, Clémentine,Guitard, Romain,Penverne, Christophe,Favier, Dominique,Nardello-Rataj, Véronique,Aubry, Jean-Marie
supporting information
p. 418 - 427
(2015/10/19)

O-eugenol: A versatile molecule for production of polyfunctional alkenes via organometallic catalysis
In this study, the synthesis and cross metathesis of o-eugenol (2-allyl-6-methoxy phenol) has been investigated. Synthesis was conducted through two stages of reaction. The first step in the synthetic procedure was to obtain the intermediate 1-but-3-enyl-2-methoxy benzene. Then the heating of the obtained intermediate will initiate will initiate a [3,3] sigmatropic rearrangement to give the o-eugenol with a good yield. The ruthenium-catalyzed cross-metathesis of o-eugenol derivatives with electron deficient olefins including methyl acrylate, acrylonitrile and acrylamides was also reported. In addition the polymerization of 1-allyl-2-(allyloxy)-3-methoxybenzene was possible by acyclic diene metathesis and this allowed to synthesize a polymer from a natural substrate. All the resulting structures were supported by the spectroscopic data.
Al-Ayed, Abdullah Sulaiman,Hamdi, Naceur,Peruzzini, Maurizio
p. 960 - 964
(2016/03/01)

Eugenol synthesis method
The invention belongs to the field of organic synthesis and particularly relates to a eugenol synthesis method. According to the eugenol synthesis method, guaiacol and allyl chloride are used as raw materials and are subjected to a catalytic reaction through a catalyst THLD to generate eugenol; an experiment testifies that the eugenol is synthesized by using the novel composite catalyst THLD, so that the conversion rate of the guaiacol and the yield of the eugenol are greatly improved, the conversion rate of the guaiacol reaches to 98 percent and the yield of the eugenol reaches to 88 percent.
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Paragraph 0042; 0043; 0044; 0045; 0046

(2016/10/08)

CLAISEN REARRANGEMENT OF ALLYL ARYL ETHERS CATALYSED BY ALKALINE-EARTH-METAL SALT
Disclosed is an effective catalytic process for carrying out a Claisen rearrangement reaction, comprising reacting an allyl aryl ether in the presence of a metal salt catalyst, wherein the metal salt catalyst is an alkaline-earth-metal triflate salt or an alkaline-earth-metal triflimide salt, wherein the alkaline-earth-metal is selected from a group consisting of magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba).
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Paragraph 0041

(2016/04/26)

A diastereoselective route to trans-2-aryl-2,3-dihydrobenzofurans through sequential cross-metathesis/isomerization/allylboration reactions: Synthesis of bioactive neolignans
A new highly diastereoselective synthetic route to trans-2,3-dihydrobenzofuran systems, in particular those bearing an aryl substituent at the C2 position, is described. The cornerstone of our strategy is the implementation of a cross-metathesis/isomerization/allylboration sequence starting from 2-allyl-substituted phenols and aldehydes. After an intramolecular Mitsunobu cyclization step, the anti-homoallylic alcohols allow the synthesis of the desired skeleton in a stereoselective fashion. As an illustration, we used this strategy for the preparation of the dihydrodehydrodiconiferyl alcohol (1a), a natural dihydrobenzofuran neolignan, as well as for a formal synthesis of its O-demethylated derivative 1b. An enantioselective version of this approach employing a chiral phosphoric acid in the allylboration step is also studied.
Hemelaere, Rémy,Carreaux, Fran?ois,Carboni, Bertrand
supporting information
p. 2470 - 2481
(2015/04/22)

PROCESS FOR PREPARING SYNTHETIC PARA-EUGENOL
Processes are provided for preparing synthetic para-eugenol and polysiloxane- polycarbonate copolymers including the synthetic para-eugenol. In an embodiment, a process for synthesizing para-eugenol can comprise: a) hydrolyzing methyl 5-allyl-3- methoxysalicylate to form 5-allyl-3-methoxysalicylic acid; b) decarboxylating the 5-allyl-3- methoxysalicylic acid to form a product comprising para-eugenol. The polysiloxane- polycarbonate copolymer prepared by the process may be isolated by, for example, anti- solvent precipitation followed by vacuum drying.
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Paragraph 0119-0121

(2015/02/25)

PdI2-catalyzed regioselective cyclocarbonylation of 2-allyl phenols to dihydrocoumarins
A simple, efficient, and regioselective synthesis of 3-methyl-3,4-dihydrocoumarins is reported. The reaction of 2-allyl phenols with synthesis gas was catalyzed by PdI2, and 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphaadamantane (L1) and 1,3,5,7-tetramethyl-6-tetradecyl-2,4,8-trioxa-6-phosphaadamantane (L2) were effective as ligands, affording good product selectivity in all cases.
Amzquita-Valencia, Manuel,Alper, Howard
supporting information
p. 5827 - 5829
(2015/01/08)

Enantioselective synthesis of benzofurans and benzoxazines via an olefin cross-metathesis-intramolecular oxo-Michael reaction
Chiral phosphoric acid and Hoveyda-Grubbs II were found to catalyze an olefin cross-metathesis-intramolecular oxo-Michael cascade reaction of the ortho-allylphenols and enones to provide a variety of benzofuran and benzoxazine derivatives in moderate to good yields and enantioselectivity.
Zhang, Jun-Wei,Cai, Quan,Gu, Qing,Shi, Xiao-Xin,You, Shu-Li
supporting information
p. 7750 - 7752
(2013/09/02)

Microwave-assisted zeolite catalyzed claisen rearrangement of allyl aryl ethers under solvent-free conditions
Claisen rearrangement of allyl aryl ethers has been studied extensively over various zeolites under microwave activation and solvent free conditions at 80°C. Hβ-zeolite is found to be an efficient catalyst for the rearrangement. The reaction gives ω-rearranged product selectively instead of expected further cyclized dihydrobenzofuran derivative.
Deodhar, Deepak K.,Tipnis, Amol S.,Samant, Shriniwas D
experimental part
p. 1552 - 1555
(2011/02/23)

Agonists and antagonists of antennal responses of gypsy moth (Lymantria dispar) to the pheromone (+)-disparlure and other odorants
Insects use the sense of smell to guide many behaviors that are important for their survival. The gypsy moth uses a pheromone to bring females and males together over long distances. Male moth antennae are equipped with innervated sensory hairs that selectively respond to pheromone components and other odors. Host plant odors, in particular, are detected by moths and sometimes cause an enhancement of the antennal and behavioral responses of the moths to their pheromone. Inspired by naturally occurring agonists and antagonists of insect pheromone responses, we have screened, by electroantennogram (EAG) recordings, a collection of compound sets and of individual compounds. We have detected interference of some compounds with the EAG responses of male gypsy moth antennae to the pheromone. We describe three activities: (1) short-term inhibition or enhancement of mixed compound + pheromone plumes, (2) long-term inhibition of pure pheromone plumes following a mixed compound + pheromone plume, and (3) inhibition of the recovery phase of mixed compound + pheromone plumes. Long-term inhibition was robust, decayed within 30 s, and correlated with the inhibition of recovery: for both activities clear structure-activity patterns were detected. The commercial repellent N,N-diethyltoluamide (DEET) was included for comparison. The most active and reproducible short-term inhibitor was a mixture of 1 -allyl-2,4-dimethoxybenzene and 2-allyl-1,3-dimethoxybenzene. The most active long-term inhibitors were a set of 1-alkoxy-4-propoxybenzenes, DEET, and 1-ethoxy-4-propoxybenzene. DEET was more specific in the olfactory responses it inhibited than 1-ethoxy-4-propoxybenzene, and DEET did not inhibit recovery, whereas 1-ethoxy-4-propoxybenzene did. Target sites for the three activities are discussed.
Plettner, Erika,Gries, Regine
body text
p. 3708 - 3719
(2011/07/30)

Dialkoxybenzene and dialkoxyallylbenzene feeding and oviposition deterrents against the cabbage looper, trichoplusia ni: Potential insect behavior control agents
The antifeedant, oviposition deterrent, and toxic effects of individual dialkoxybenzene compounds/sets and of hydroxy- or alkoxy-substituted allylbenzenes, obtained through Claisen rearrangement of substituted allyloxybenzenes, were assessed against the cabbage looper, Trichoplusia ni, in laboratory bioassays. Most of the compounds/sets strongly deterred larval feeding, with some exhibiting mild toxic and oviposition deterrent effects as well. Some of the compounds/sets were more active than the commercial insect repellent, DEET (N,N-diethyl-m-toluamide), as both feeding and oviposition deterrents against the cabbage looper. On the basis of the obtained oviposition data a general hypothesis was proposed regarding the oviposition sites: one binding mode with the alkyl and allyl groups on the same side of the benzene ring resulted in deterrence, the other with alkyl and allyl groups on opposite sides of the benzene ring resulted in stimulation. The results suggest some structure-activity relationships useful in improving the efficacy of the compounds and designing new, nontoxic insect control agents for agriculture.
Akhtar, Yasmin,Yu, Yang,Isman, Murray B.,Plettner, Erika
scheme or table
p. 4983 - 4991
(2011/08/06)

Stereoselective construction of substituted chromans by palladium-catalyzed cyclization of propargylic carbonates with 2-(2-Hydroxyphenyl)acetates
Highly substituted chromans have been constructed In a highly stereoselective manner by a palladium-catalyzed reaction of propargylic carbonates with 2-(2-hydroxyphenyl)acetates. Enantioselective reactions also successfully proceeded to give the optically active chromans with high enantioselectivity.
Yoshida, Masahiro,Higuchi, Mariko,Shishido, Kozo
supporting information; experimental part
p. 4752 - 4755
(2009/12/09)

Selective O-deallylation of o-allyloxyanisoles
o-Allyloxyanisoles are selectively and easily deallylated by treatment with sec- or tert-butyllithium at low temperature. The reaction is proposed to proceed through a tandem intermolecular carbolithiation-β;-elimination process, which can also be considered an SN2′ attack of the organolithium on the allyl ether.
Sanz, Roberto,Martínez, Alberto,Marcos, César,Fa?ańas, Francisco J.
experimental part
p. 1957 - 1960
(2009/05/26)

Synthesis of aromatic spiroacetals related to γ-rubromycin based on a 3H-spiro[1-benzofuran-2,2′-chromane] skeleton
The synthesis of a series of aromatic 5,6-benzannelated and naphthyl-benzannelated spiroacetals related to the spiroacetal unit present in the quinonoid antibiotic γ-rubromycin is reported. The key steps include the use of Sonogashira coupling to construct an aryl acetylene that is coupled to an aryl aldehyde forming a propargyl alcohol intermediate. Hydrogenation of the resultant alkynol followed by oxidation produces a masked dihydroxyketone that upon treatment with silica-supported sodium hydrogen sulfate undergoes concomitant deprotection and cyclisation to afford the desired fused aromatic spiroacetal.
Tsang, Kit Yee,Brimble, Margaret A.
p. 6015 - 6034
(2008/02/02)

Microwave-accelerated Claisen rearrangement in bicyclic imidazolium [b-3C-im][NTf2] ionic liquid
With microwaves, a chemically stable ionic liquid [b-3C-im][NTf2] recently developed in our laboratory was used as solvent and successfully applied to accelerate Claisen rearrangement reactions at high temperatures. In the presence of Lewis acid MgCl2, these thermal rearrangements could be achieved in similar reaction times but at lower temperature. For the microwaved reactions studied in this work, without scarifying isolated yields, the reaction times were significantly reduced from hours (by conventional heating) to ≤3 min. Our result also demonstrated that [b-3C-im][NTf2] ionic liquid was a useful solvent substitute and could be recycled multiple times for the studied rearrangement reaction at elevated temperatures.
Lin, Yung-Lun,Cheng, Jen-Yen,Chu, Yen-Ho
p. 10949 - 10957
(2008/02/13)

A facile synthesis of fused aromatic spiroacetals based on the 3,4,3′,4′-tetrahydro-2,2′-spirobis(2H-1-benzopyran) skeleton
The facile synthesis of a series of aromatic 6,6-spiroacetals based on the parent 3,4,3′,4′-tetrahydro-2,2′-spirobis(2H-1-benzopyran) heterocyclic system is reported. Key steps included the use of a Sonogashira coupling for the synthesis of an aryl acetylene that was coupled to an aryl aldehyde to form a propargyl alcohol intermediate. Hydrogenation of the alkynol followed by oxidation produced a masked dihydroxy ketone that upon treatment with trimethylsilyl bromide underwent deprotection and cyclisation to the fused aromatic spiroacetal.
Brimble, Margaret A.,Flowers, Christopher L.,Trzoss, Michael,Tsang, Kit Y.
p. 5883 - 5896
(2007/10/03)

Studies towards the total synthesis of Sch 56036; isoquinolinone synthesis and the synthesis of phenanthrenes
The isoquinolinone hemisphere of Sch 56036 has been prepared using a modified Pomeranz-Fritsch reaction and the synthesis of the phenanthrene core has been modelled via a Suzuki coupling and subsequent ring closing metathesis.
Walker, Edward R.,Leung, Shing Y.,Barrett, Anthony G.M.
p. 6537 - 6540
(2007/10/03)

DIHYDROBENZOFURANYL ALKANAMINE DERIVATIVES AS 5HT2C AGONISTS
Compounds of Formula (I) or pharmaceutically acceptable salts thereof are provided: Formula (I) which are agonists or partial agonists of the 2C subtype of brain serotonin receptors. The compounds, and compositions containing the compounds, can be used to treat a variety of central nervous system disorders such as schizophrenia.
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Page/Page column 58-59

(2008/06/13)

Bismuth(III) triflate: Novel and efficient catalyst for Claisen and Fries rearrangements of allyl ethers and phenyl esters
Bismuth(III) triflate catalyzed Claisen and Fries rearrangements of allyl phenyl ethers and phenyl acetates have been presented. The reaction proceeds smoothly and yields corresponding rearranged products in good yields. The bismuth triflate displays higher activity over the corresponding La, Yb, and Sc triflates.
Sreedhar,Swapna,Sridhar
p. 1433 - 1440
(2007/10/03)

Synthesis of coumarins by ring-closing metathesis using Grubbs' catalyst
A novel generally applicable synthesis of coumarins from phenolic substrates utilizing ring-closing metathesis is described. This sequence involves O-allylation of phenols followed by ortho-Claisen rearrangement, subsequent based-induced isomerization affording 2-(1-propenyl)phenols, acylation with acryloyl chloride, and finally ring-closing metathesis (RCM) with Grubbs' second generation catalyst.
Nguyen Van, Tuyen,Debenedetti, Silvia,De Kimpe, Norbert
p. 4199 - 4201
(2007/10/03)

Use of a Sonogashira - Acetylide Coupling Strategy for the Synthesis of the Aromatic Spiroketal Skeleton of γ-Rubromycin
(Equation presented) The synthesis of the fused aromatic spiroketal core of γ-rubromycin is described via addition of an aryl acetylide fragment to an aryl acetaldehyde fragment. In turn, the aryl acetylene precursor was readily prepared with use of a Sonogashira reaction.
Tsang, Kit Y.,Brimble, Margaret A.,Bremner, John B.
p. 4425 - 4427
(2007/10/03)

Water-Accelerated Claisen Rearrangements
Allyl aryl ethers undergo accelerated Claisen and [1,3] rearrangements in the presence of a mixture of trialkylalanes and water or aluminoxanes. The ratio of ortho-, meta-, and pora-Claisen products depends to a large extent on the presence of water and to a much lesser extent on the nature of the alane.
Wipf, Peter,Rodriguez, Sonia
p. 434 - 440
(2007/10/03)

Synthesis of the bisbenzannelated spiroketal core of the γ-rubromycins. The use of a novel Nef-type reaction mediated by Pearlman's catalyst
The synthesis of the bisbenzannelated spiroketal core 6 of γ-rubromycin 1 from the substituted nitrostyrene 20 was achieved by using a novel Nef-type reaction mediated by Pearlman's catalyst. The precursor 28 was synthesised from readily prepared starting materials using Henry condensation chemistry. The product 6 was found to exist in two conformations in solution as shown by NMR spectroscopy.
Capecchi, Tanya,De Koning, Charles B.,Michael, Joseph P.
p. 2681 - 2688
(2007/10/03)

Alternative Lewis acids to effect Claisen rearrangement
Yb(OTf)3 and DIBAL-H are developed as alternative Lewis acids for effecting Claisen rearrangement of allyl, crotyl and prenyl aryl ethers.
Sharma,Ilangovan,Sreenivas, Punna,Mahalingam
p. 615 - 618
(2007/10/03)

Facile synthesis of 5,6-dimethoxy-1-tetralone
A facile synthesis of 5,6-dimethoxy-1-tetralone, a key intermediate in the synthesis of an antidepressant compound, ABT-200, was developed from the inexpensive starting material guaiacol.
Lahiri, Saswata,Ramarao,Rao, B. Venkateswara,Rao, A.V. Rama,Chorghade, Mukund S.
p. 71 - 72
(2013/09/08)

Synthesis of Naturally Occuring 5-Allyl-2-aryl-7-methoxybenzofurans and 2-Aryl-5-(3-hydroxypropyl)-7-methoxybenzofurans
A convenient and general procedure is described for the synthesis of 5-allyl-2-aryl-7-methoxybenzofurans (8a-e) from 2-allyloxy-3-methoxybenzaldehyde (3).The compounds 8a and 8b on hydraboration followed by oxidation provide the naturally occuring benzofurans (1a and 1b)
Mali, Raghao S.,Massey, Archna Patience
p. 1109 - 1120
(2007/10/03)

Nitroalkenes as precursors to the aromatic spiroketal skeleton of γ- rubromycin. A Nef-type reaction mediated by Pearlman's catalyst
The first synthesis of the benzannelated spiroketal core of γ- rubromycin using Henry condensations and a novel Nef-type reaction induced by Pearlman's catalyst is described.
Capecchi, Tanya,De Koning, Charles B.,Michael, Joseph P.
p. 5429 - 5432
(2007/10/03)

Studies of the Claisen Rearrangement. VII. Catalytic Effect of Alkaline-earth-metal Salts on the Claisen Rearrangements of o- and p-Allyloxyphenol
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Hayashi, Takatoshi,Okada, Yutaka,Inaba, Takeshi
p. 1758 - 1770
(2007/10/02)

Synthesis of Isoquinoline Derivatives by a Tandem Aza-Wittig/Electrocyclization Strategy and Preparation of the Unknown 1,9-Diazaphenalene Ring by a Consecutive Electrocyclic Ring Closure/Claisen Rearrangement/Intramolecular Amination Process
Treatment of iminophosphorane 3, derived from ethyl α-azido-2-(allyloxy)cinnamate, with aromatic isocyanates in toluene at 150 deg C leads to the corresponding isoquinoline derivatives 5 by a tandem electrocyclic ring closure/Claisen rearrangement of the intermediate carbodiimide.Fremy's salt promoted oxidation of compounds 5 yields the 5,8-isoquinolinequinone allides 6, which by heating undergo cyclization to 2H-pyranoisoquinolines 7.Iminophosphorane 14, derived from ethyl α-azido-2-(allyloxy)-3-methoxycinnamate, reacts with aromatic isocyanates to give thecorresponding carbodiimides, which by thermal treatment at 150 deg C undergo a consecutive electrocyclic ring closure/Claisen rearrangement/intramolecular amination process to give 1,9-diazaphenalene derivatives 18 in moderate yields.
Molina, Pedro,Alajarin, Mateo,Vidal, Angel
p. 6140 - 6147
(2007/10/02)

Microwave-Induced Reactions of Organic Substrates in the Cage of Zeolites
Microwave irradiation of compounds 1, 7, 15, 19, 23, and 24 adsorbed on Y zeolites has been studied.The reaction rate of the corresponding rearrangement, dehydrogenation and dehydration is dramatically enhanced as compared with reactions under thermal conditions.
Ipaktschi, Junes,Brueck, Matthias
p. 1591 - 1593
(2007/10/02)

BIOMIMETIC RADICAL CYCLISATIONS: SYNTHESIS AND BIOSYNTHESIS OF BENZODIHYDRO-PYRANES AND -FURANS
Aryloxymethylene radicals generated by decarboxilation of the thiohydroxamate esters derived from acids (8a), (10a), and (12) undergo 6-endo cyclisation yielding (9), (11), and (14) respectively, mimicking the unusual biosynthetic reactions involved in formation of (1), (3), and (4) in nature.
Walkington, Andrew J.,Whiting, Donald A.
p. 4731 - 4734
(2007/10/02)

Synthesis of methyl 2,3-dihydro-2-benzofurancarboxylates from o-allylphenols via 2-(phenylthiomethyl)-2,3-dihydrobenzofurans
A method for synthesizing methyl 2,3-dihydro-2-benzofurancarboxylates rom o-allylphenols is described.The reaction of 6allyl-2,3-dichlorophenol (3) with benzenesulfenyl chloride (PhSCl) in acetonitrile gave a mixture of PhSCl -adducts, which was heated in aqueous acetonitrile then with sodium bicarbonate to obtain 6,7-dichloro-2-(phenylmethyl)-2,3-dihydrobenzofuran (6). α-Dichlorination of the phenylthiomethyl group of 6 and subsequent methanolysis gave the methyl ester 5 in high yield.The generality of this synthetic method was examined by the conversion of o-allylphenols 11 having various substituents on the benzene ring into the corresponding methyl ester 23.Cyclization of 11 to sulfides 12 could be achived similerly to the case of 3.However, in the subsequent conversions of 12 to 23, selective α-dichlorination followed by methanolysis could be achived only with 12 substituted with an electron-withdrawing group such as a chloro or nitro group.Keywords - oallylphenils; methyl 2,3-dihydro-2-benzofurancarboxylate; 2-(phenylthiomethyl)-2,3-dihydrobenzofuran; benzenesulfenyl chloride; α-chlorination; methanolysis.
Yodo, Mitsuaki,Harada, Hiroshi
p. 2361 - 2368
(2007/10/02)

APPLICATION OF COMMERCIAL MICROWAVE OVENS TO ORGANIC SYNTHESIS.
Commercial microwave ovens have been safely used to dramatically reduce the reaction times (at comparable yield) of Diels-Alder, Claisen, and ene reactions.Significant solvent effects were also observed.
Giguere, Raymond J.,Bray, Terry L.,Duncan, Scott M.
p. 4945 - 4948
(2007/10/02)

Process for preparing o-alkoxy-p-allylphenols
In a process for preparing an o-alkoxy-p-allylphenol comprising reaction of an o-alkoxyphenol with an allyl halide in the presence of an aqueous solution of an alkali metal hydroxide or alkaline earth metal hydroxide, the improvement which comprises employing a copper-containing compound such as a water-soluble copper salt, an ammine copper complex salt etc., as the catalyst. The process for preparing an o-alkoxy-p-allylphenol which comprises reaction of an o-alkoxyphenol with an allyl halide in an aqueous ammonia is also disclosed.
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(2008/06/13)