- Total Synthesis of Suillusin
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The first total synthesis of the fungal natural product suillusin is reported. The key features of the synthesis include a Michael-benzoin multicatalytic cascade that assembles the entire carbon framework in a single step, and a Rubottom-Swern oxidation s
- Zhang, Meng Yao,Malins, Lara R.,Ward, Jas S.,Barrow, Russell A.
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- Design and synthesis of dual active neovibsanin derivatives based on a chemical structure merging method
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A hybrid compound consisting of neovibsanin and trans-banglene was designed according to a structure merging method and synthesized via a sequence of key steps including a Diels–Alder cycloaddition, stereoselective alkynylation, and intramolecular oxa-Mic
- Fukuyama, Yoshiyasu,Imagawa, Hiroshi,Kasai, Yusuke,Kishimoto, Suguru,Kubo, Miwa,Matsui, Nobuaki,Yamamoto, Hirofumi,Yanagimoto, Tsuyoshi
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- Hendrickson reagent induced rearrangement of aryl propargyl alcohols to α,β-unsaturated aldehydes
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The Hendrickson reagent (triphenylphosphonium anhydride trifluoromethanesulfonate), prepared from the reaction of triphenylphosphine oxide (Ph3PO) and triflic anhydride (Tf2O) (2:1 stoichiometry), promotes dehydrations and various coupling reactions. The reagent has been used to transform oximes to nitriles and to prepare esters, amides and many other functional groups through the intermediacy of an alkoxyphosphonium salt. The reagent proved useful in heterocycle synthesis of thiazolines, imidazolines, quinoline precursors, isoquinolines, β-carbolines, phenanthridines, 11H-indolo[3,2-c]quinolines, quinoline-lactones, furoquinolinones, and indolizino[1,2-b]quinolin-9(11H)-ones. Moreover, the reagent has been key to the successful total synthesis of several natural products. Aryl propargyl alcohols with a terminal α-acetylenic group undergo rapid conversion to the corresponding α,β-unsaturated aldehydes at room temperature in dichloromethane in the presence of one equivalent of triphenylphosphonium anhydride trifluoromethanesulfonate. The reaction involved adding freshly distilled Tf2O (1.0 mmol) to a solution of Ph3PO (2.0 mmol) in CH2Cl2 (10 mL) at 0oC under N2 atmosphere. After stirring for 10 min, the propargyl alcohol (1.0 mmol) was added as a CH2Cl2 solution (2 mL), followed by the addition of water and Et3N (2.0 mmol) and further stirring at room temperature for 1h. Subsequent workup with 5% NaHCO3 (20 mL) and purification afforded α,β-unsaturated aldehydes. Eighteen aryl propargyl alcohol substrates with a terminal α-acetylenic group were transformed in good to excellent yields (71-85%) to enals. The methodology proved successful with secondary and tertiary alcohols with stereoselectivity favouring exclusively the E isomer. All the synthesized compounds are known and were characterized (1H,13C, and M.P) and compared to literature values. The method offers several advantages such as exclusive stereoselectivity, short reaction time, good yield, mild reaction conditions, and simple operational procedure.
- Moussa, Ziad,Aljuhani, Ateyatallah
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p. 845 - 853
(2018/11/06)
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- Copper-catalyzed formylation of alkenyl C-H bonds using BrCHCl2 as a stoichiometric formylating reagent
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The first example of copper-catalyzed direct formylation of alkenyl C-H bonds for the facile synthesis of α,β-unsaturated aldehydes has been developed. This transformation has demonstrated high reactivity, mild reaction conditions and a broad substrate scope. BrCHCl2 is expected to be developed as an efficient stoichiometric C1 building block in organic synthesis.
- Bao, Yan,Wang, Gao-Yin,Zhang, Ya-Xuan,Bian, Kang-Jie,Wang, Xi-Sheng
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p. 2986 - 2990
(2018/03/23)
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- Unravelling Some of the Key Transformations in the Hydrothermal Liquefaction of Lignin
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Using both experimental and computational methods, focusing on intermediates and model compounds, some of the main features of the reaction mechanisms that operate during the hydrothermal processing of lignin were elucidated. Key reaction pathways and their connection to different structural features of lignin were proposed. Under neutral conditions, subcritical water was demonstrated to act as a bifunctional acid/base catalyst for the dissection of lignin structures. In a complex web of mutually dependent interactions, guaiacyl units within lignin were shown to significantly affect overall lignin reactivity.
- Lui, Matthew Y.,Chan, Bun,Yuen, Alexander K. L.,Masters, Anthony F.,Montoya, Alejandro,Maschmeyer, Thomas
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p. 2140 - 2144
(2017/05/29)
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- Supported palladium nanoparticles as switchable catalyst for aldehyde conjugate/s and acetate ester syntheses from alcohols
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Polymer-supported Pd(0) (Pd@PS) nanoparticles (NPs) were explored as a switchable catalyst for oxidative aldehyde conjugate/s (AC/s) and acetate esters (AEs) syntheses from alcohols. Using the same substrates, the catalyst in the presence of oxygen and K2CO3 participated in AC/s synthesis, and in the presence of traces of air and NaOtBu, unusual AEs products were obtained.
- Kumar, Sandeep,Chaudhary, Abha,Bandna,Bhattacherjee, Dhananjay,Thakur, Vandna,Das, Pralay
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supporting information
p. 3242 - 3245
(2017/07/12)
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- Stereoselective organocatalytic oxidation of alcohols to enals: A homologation method to prepare polyenes
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A novel method for organocatalytic oxidation through oxidative enamine catalysis was developed with excellent compatibility for the direct syntheses of enals from simple saturated alcohols. By using this amine-catalyzed IBX-oxidation, a wide range of aromatic and aliphatic substituted enals were successfully generated in high yields and exclusively stereoselective E-geometry. Moreover, varying the solvents and/or the loading amounts of IBX allowed for the selective oxidation of alcohols and aldehydes. Importantly, the homologous application of this method provided a selective and efficient way of preparing various highly sensitive conjugated polyene frameworks, which are enriched in natural products.
- Chen, Xiaobei,Zhang, Yinan,Wan, Huixin,Wang, Wei,Zhang, Shilei
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supporting information
p. 3532 - 3535
(2016/03/04)
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- Novel chromone and xanthone derivatives: Synthesis and ROS/RNS scavenging activities
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Chromones and xanthones are oxygen-containing heterocyclic compounds acknowledged by their antioxidant properties. In an effort to develop novel agents with improved activity, a series of compounds belonging to these chemical classes were prepared. Their syntheses involve the condensation of appropriate 2-methyl-4H-chromen-4-ones, obtained via Baker-Venkataraman rearrangement, with (E)-3-(3,4-dimethoxyphenyl)acrylaldehyde to provide the corresponding 2-[(1E,3E)-4-(3,4-dimethoxyphenyl)buta-1,3-dien-1-yl]-4H-chromen-4-ones. Subsequent electrocyclization and oxidation of these compounds led to the synthesis of 1-aryl-9H-xanthen-9-ones. After cleavage of the protecting groups, hydroxylated chromones and xanthones were assessed as scavenging agents against both reactive oxygen species (ROS) [superoxide radical (O2?-), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen (1O2), and peroxyl radical (ROO?)] and reactive nitrogen species (RNS) [nitric oxide (?NO) and peroxynitrite anion (ONOO-)]. Generally, all the tested new hydroxylated chromones and xanthones exhibited scavenger effects dependent on the concentration, with IC50 values found in the micromolar range. Some of them were shown to have improved scavenging activity when compared with previously reported analogues, allowing the inference of preliminary conclusions on the structure-activity relationship.
- Proen?a, Carina,Albuquerque, Hélio M.T.,Ribeiro, Daniela,Freitas, Marisa,Santos, Clementina M.M.,Silva, Artur M.S.,Fernandes, Eduarda
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p. 381 - 392
(2016/04/06)
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- New polyhydroxylated flavon-3-ols and 3-hydroxy-2-styrylchromones: Synthesis and ROS/RNS scavenging activities
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New polyhydroxylated flavon-3-ols and 3-hydroxy-2-styrylchromones were prepared and assessed as reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavengers. The synthetic strategy involved the preparation of 2′-hydroxychalcones and 2′-hyd
- Sousa, Joana L.C.,Proen?a, Carina,Freitas, Marisa,Fernandes, Eduarda,Silva, Artur M.S.
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p. 250 - 259
(2016/06/01)
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- Electronic and steric effects on the intramolecular Schmidt reaction of alkyl azides with secondary benzyl alcohols
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The intramolecular Schmidt reaction of simple azido secondary benzyl alcohols has been realized for the first time. Investigation of the electronic and steric effects of the substrates on the product outcome was conducted. Unique intramolecular Schmidt rearrangements were observed with the formation of a cinnamaldehyde derivative and aryl aldehydes, respectively. Using this protocol, an efficient synthesis of dihydrobenzotriazine derivatives was achieved. Moreover, a practical approach to 2-aryl-1-pyrrolines was also accessed.
- Sun, Xiaowei,Gao, Chengzhe,Zhang, Fan,Song, Zhuang,Kong, Lingyi,Wen, Xiaoan,Sun, Hongbin
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p. 643 - 649
(2014/02/14)
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- Synthesis of methoxylated goniothalamin, aza-goniothalamin and γ-pyrones and their in vitro evaluation against human cancer cells
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The present work describes the preparation of three novel series of compounds based on the structure of goniothalamin, a natural styryl lactone which has been found to display cytotoxic and antiproliferative activities against a variety of cancer cell lines. A focused library of 29 novel goniothalamin analogues was prepared and evaluated against seven human cancer cell lines. While the γ-pyrones and the aza-goniothalamin analogues were less potent than the lead compound, 2,4-dimethoxy analogue 88 has shown to be more potent in vitro than goniothalamin against all cancer cell lines evaluated. Furthermore, it was more potent than doxorubicin against NCI-ADR/RES, OVCAR-03 and HT-29 while being less toxic to human keratinocytes (HaCat). The 3,5-dimethoxy analogue 90 and 2,4,5-trimethoxy analogue 92 also displayed promising antiproliferative activity when compared to goniothalamin (1). These results provide new elements for the design and synthesis of novel representatives of this family of natural compounds.
- Barcelos, Rosimeire Coura,Pastre, Julio Cezar,Caixeta, Vanessa,Vendramini-Costa, Débora Barbosa,De Carvalho, Jo?o Ernesto,Pilli, Ronaldo Aloise
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p. 3635 - 3651
(2012/07/27)
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- An efficient route to xanthine based A2A adenosine receptor antagonists and functional derivatives
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A one-pot route to 8-substituted xanthines has been developed from 5,6-diaminouracils and carboxaldehydes. Yields are good and the process applicable to a range of substrates including a family of A2A adenosine receptor antagonists. A new route to the KW-6002 family of antagonists is presented including a pro-drug variant, and application to related image contrast agents developed.
- Labeaume, Paul,Dong, Ma,Sitkovsky, Michail,Jones, Elizabeth V.,Thomas, Rhiannon,Sadler, Sara,Kallmerten, Amy E.,Jones, Graham B.
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supporting information; experimental part
p. 4155 - 4157
(2010/10/21)
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- Total synthesis of (+)-virgatusin via AlCl3-catalyzed [3+2] cycloaddition
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The AlCl3-catalyzed cycloaddition of a donor-acceptor (don-acc) cyclopropane and piperonal succinctly provides the core of virgatusin in a selective, high-yielding manner. The Royal Society of Chemistry 2009.
- Sanders, Shanina D.,Ruiz-Olalla, Andrea,Johnson, Jeffrey S.
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supporting information; experimental part
p. 5135 - 5137
(2009/12/08)
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- COMPOUNDS WITH (SUBSTITUTED PHENYL)-PROPENAL MOIETY, THEIR DERIVATIVES, BIOLOGICAL ACTIVITY, AND USES THEREOF
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The present invention includes compounds, pharmaceuticals and cosmetics having at least one (substituted phenyl)-propenal moiety. The compounds and compositions of the present invention are useful in the treatment or prevention of many medical conditions such as androgen associated conditions. The present invention also includes methods of treating a medical condition including an androgen associated condition, using at least one of the disclosed compounds.
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Page/Page column 30; 46-48
(2008/12/07)
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- Antitumor agents. 250. Design and synthesis of new curcumin analogues as potential anti-prostate cancer agents
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In a continuing study of curcumin analogues as potential drug candidates to treat prostate cancer at both androgen-dependent and androgen-refractory stages, we designed and synthesized over 40 new analogues classified into four series: monophenyl analogues (series A), heterocycle-containing analogues (series B), analogues bearing various substituents on the phenyl rings (series C), and analogues with various linkers (series D). These new compounds were tested for cytotoxicity against two human prostate cancer cell lines, androgen-dependent LNCaP and androgen-independent PC-3. Antiandrogenic activity was also evaluated in LNCaP cells and PC-3 cells transfected with wild-type androgen receptor. Ten compounds possessed potent cytotoxicity against both LNCaP and PC-3 cells, seven only against LNCaP, and one solely against PC-3. This study established an advanced structure-activity relationship (SAR), and these correlations will guide the further design of new curcumin analogues with better anti-prostate cancer activity.
- Lin, Li,Shi, Qian,Nyarko, Alexander K.,Bastow, Kenneth F.,Wu, Chin-Chung,Su, Ching-Yuan,Shih, Charles C.-Y.,Lee, Kuo-Hsiung
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p. 3963 - 3972
(2007/10/03)
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- Efficient one-pot, two-step synthesis of (E)-cinnmaldehydes by dehydrogenation-oxidation of arylpropanes using DDQ under ultrasonic irradiation
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A general, efficient and new approach to the synthesis of cinnamaldehydes with trans-selectivity has been accomplished starting from arylpropanes. One-pot, two-step dehydrogenation and oxidation of arylpropanes with excess DDQ in dioxane containing a few drops of acetic acid gave (E)-cinnmaldehydes under ultrasound irradiation.
- Joshi, Bhupendra P.,Sharma, Anuj,Sinha, Arun K.
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p. 2590 - 2593
(2007/10/03)
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- Ultrasound-assisted convenient synthesis of hypolipidemic active natural methoxylated (E)-arylalkenes and arylalkanones
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An ultrasound-assisted convenient method was developed for the conversion of toxic methoxylated cis-isomer of arylalkenes into its hypolipidemic active trans-isomer. Treatment of cis-isomer or mixture of all three isomers (1a-1j) with ammonium formate and 10% Pd/C gave arylalkanes (2a-2j), which upon oxidation with DDQ in anhydrous dioxane containing a little amount of silica gel, provided (E)-arylalkenes (3a-3g) in 42-72% yield depending upon the substituents attached at the aryl ring. The same method, upon addition of a few drops of water, provided hypolipidemic active arylalkanones (3h-3j) in 59-65% yield.
- Joshi, Bhupendra P.,Sharma, Anuj,Sinha, Arun K.
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p. 3075 - 3080
(2007/10/03)
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- NOVEL COMPOUNDS FOR MODULATING CELL PROLIFERATION
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Novel styrylacrylonitrile compounds which are useful in treating a variety of cell proliferative disorders such as cancer are disclosed.
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Page/Page column 89-90
(2008/06/13)
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- A new lead compound for abscisic acid biosynthesis inhibitors targeting 9-cis-epoxycarotenoid dioxygenase
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9-cis-Epoxycarotenoid dioxygenase (NCED), a key enzyme in abscisic acid (ABA) biosynthesis, cleaves the olefinic double bond of 9-cis-epoxycarotenoid. Several analogues of nordihydroguaiaretic acid (NDGA) were designed and synthesized, and their efficacy
- Han, Sun-Young,Kitahata, Nobutaka,Saito, Tamio,Kobayashi, Masatomo,Shinozaki, Kazuo,Yoshida, Shigeo,Asami, Tadao
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p. 3033 - 3036
(2007/10/03)
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- Utilization of 1-Aryl-2,2-dibromocyclopropanes in synthetic approaches to phenanthroquinolizidine and phenanthroindolizidine alkaloids
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The 1-aryl-2,2-dibromocyclopropane 8 was treated with silver acetate in acetic acid to give the allylic acetate 19. Exposure of the derived chloride 26 to racemic 2-piperidinemethanol (7) then afforded the allylic amine 6, which engaged in a Pd(0)-catalyz
- Banwel, Martin G.,Sydnes, Magne O.
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p. 537 - 548
(2007/10/03)
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- Tyrenes: Synthesis of new antiproliferative compounds with an extended conjugation
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A series of substituted styryl-acrylonitriles was designed and synthesized. The new compounds, called tyrenes, were tested for the ability to inhibit acute lymphocytic leukemia (ALL) cancer cell growth, as well as on their toxicity to normal bone marrow (NBM) cells. The results showed that 3,4-dihydroxystyryl- acrylonitriles, in particular CR-4, revealed great potency as antitumor agents, and also exhibited low toxicity to normal cells. The effectiveness of these compounds with extended conjugation may be due to their possible functioning as reactive Michael acceptors.
- Demin, Peter,Rounova, Olga,Grunberger, Thomas,Cimpean, Lorand,Sharfe, Nigel,Roifman, Chaim M.
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p. 3019 - 3026
(2007/10/03)
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- Novel compounds for modulating cell proliferation
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Novel styrylacrylonitrile compounds which are useful in treating a variety of cell proliferative disorders such as cancer are disclosed. The compounds are of the Formula I:
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- Antimutagenic Activity of Phenylpropanoids from Clove (Syzygium aromaticum)
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Phenylpropanoids that possess antimutagenic activity were isolated from the buds of clove (Syzygium aromaticum). The isolated compounds suppressed the expression of the umu gene following the induction of SOS response in the Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compounds were mainly localized in the ethyl acetate extract fraction of the processed clove. This ethyl acetate fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compounds. Electron impact mass spectrometry, IR, and 1H and 136 NMR spectroscopy were then used to delineate the structures of the compounds that confer the observed antimutagenic activity. The secondary suppressive compounds were identified as dehydrodieugenol (1) and trans-coniferyl aldehyde (2). When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, compound 1 suppressed 58% of the umu gene expression as compared to the controls at a concentration of 0.60 μmol/mL, with an ID50 (50% inhibitory dose) value of 0.48 μmol/mL, and compound 2 suppressed 63% of the umu gene expression as compared to the controls at a concentration of 1.20 μmol/mL, with an ID50 value of 0.76 μmol/mL. Additionally, compounds 1 and 2 were tested for their ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes, and aflatoxin B1 (AfB1) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver metabolizing enzymes and activated Trp-P-1 and UV irradiation. Compounds 1 and 2 showed dramatic reductions in their mutagenic potential of all of the aforementioned chemicals or treatment. For the search of the structure-activity relationship, the derivatives of 1 and 2 (1a and 2a-c) were also assayed with all mutagens. Finally, the antimutagenic activities of compounds 1, 1a, 2, and 2a-c against furylfuramide, Trp-P-1, and activated Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain.
- Miyazawa, Mitsuo,Hisama, Masayoshi
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p. 6413 - 6422
(2007/10/03)
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- Process for the preparation of substituted trans-cinnamaldehyde, a natural yellow dye, from phenylpropane derivatives
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The present invention relates to the preparation of substituted trans-cinnamaldehyde, a natural yellow dye from Phenylpropane derivatives having R2-R3-R4-R5-R6 substitution, wherein R2 to R6 equal or different, being hydrogen or hydroxy or acyl or halogen or alkyl or heterocyclic or aryl or dioxymethylene or alkoxy groups, etc., by oxidizing the said phenylpropane derivatives using a oxidising agent such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or p-chloranil or pyridinium chlorochromate (PCC) or tBuOOH or or CrO3 with a catalytic amount of inorganic/organic acid or alumina, celite, and silica gel as a solid support for microwave irradiation and thus substituted trans-cinnamaldehydes, a natural yellow dye, are obtained in high yield ranging from 68-82%.
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- Convenient method for the preparation of crown ether cinnamaldehydes
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A convenient route from crown ether benzaldehydes to novel crown ether cinnamaldehydes with different combinations of O and S heteroatoms in the macrocycle consisting in mild reduction of the appropriate cinnamic acid chloride has been elaborated.
- Vedernikov, Artem I.,Gromov, Sergey P.
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p. 889 - 892
(2007/10/03)
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- Process for the solid phase synthesis of aldehyde, ketone, oxime, amine, hydroxamic acid and αβ-unsaturated carboxylic acid and aldehyde compounds
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This invention is directed to a process for the solid phase synthesis of aldehyde, ketone, oxime, amine, hydroxamic acid and α,β-unsaturated carboxylic acid and aldehyde compounds and to polymeric hydroxylamine resin compounds useful therefor.
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- Structure-activity relationship of piperine and its synthetic analogues for their inhibitory potentials of rat hepatic microsomal constitutive and inducible cytochrome P450 activities
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Inhibitors of drug metabolism have important implications in pharmaco- toxicology and agriculture. We have reported earlier that piperine, a major alkaloid of black and long peppers inhibits both constitutive and inducible cytochrome P450 (CYP)-dependent drug metabolising enzymes. In the present study, an attempt has been made to prepare several novel synthetic analogues so as to relate various modifications in the parent molecule to the inhibition of CYP activities. Two types of mono-oxygenase reactions arylhydrocarbon hydroxylase (AHH) and 7-methoxycoumarin-O-demethylase (MOCD) have been studied. Inhibition studies were investigated in rat microsomal fraction prepared from untreated, 3MC- and PB- treated rat liver in vitro. Modifications were introduced into the piperine molecule: (i) in the phenyl nucleus, (ii) in the side chain and (iii) in the basic moiety. Thus, 38 compounds have been subjected to such studies, and simultaneously an attempt has also been made to arrive at the structure-activity relationship of synthetic analogues. In general, most of the inhibitory potential of the parent molecule is lost with modification in either of the three components of piperine. Saturation of the side chain resulted in significantly enhanced inhibition of CYP while modifications in the phenyl and basic moieties in few analogues offered maximal selectivity in inhibiting either constitutive or inducible CYP activities. Thus few novel analogues as CYP inactivators have been synthesized which may have important consequences in pharmacokinetics and bioavailability of drugs. (C) 2000 Elsevier Science Ltd.
- Koul, Surrinder,Koul, Jawahir L.,Taneja, Subhash C.,Dhar, Kanaya L.,Jamwal, Deshvir S.,Singh, Kuldeep,Reen, Rashmeet K.,Singh, Jaswant
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p. 251 - 268
(2007/10/03)
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- Parallel synthesis of aldehydes and ketone facilitated by a new solid- phase Weinreb amide
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This paper describes a novel supported Weinreb amide resin that facilitates parallel synthesis of aldehydes and ketones on a scale useful for chemical library synthesis. This new resin makes it possible to produce custom aldehydes and ketones from a wide range of carboxylic acids, including N-BOC-amino acids. A variety of commercially unavailable aldehydes are easily synthesized in parallel and obtained in high purity via a simple filtration workup, thus facilitating parallel synthesis of lead optimization libraries that typically require custom synthesis of aldehyde intermediates for development of structure-activity relationships. To demonstrate the utility of this method, we synthesized a small library based on a supported Horner- Emmons reagent. This is the first time it has been shown that aldehydes generated via a supported Weinreb amide could be used directly as reagents in chemical library synthesis employing moisture-sensitive reactions. The analogous solution reaction is not suited for parallel synthesis because of the laborious extractive workup procedure necessary and, at times, the instability of these reactive intermediates.
- Salvino, Joseph M.,Mervic, Miljenko,Mason, Helen J.,Kiesow, Terence,Teager, David,Airey, John,Labaudiniere, Richard
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p. 1823 - 1830
(2007/10/03)
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- Synthesis of cinnamaldehydes, esters of cinnamic acids and acylals of cinnamaldehydes by oxidation of arylpropenes with 2,3-dicyano-5,6- dichlorobenzoquinone (DDQ)
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1-Arylpropenes and 3-arylpropenes give cinnamaldehydes (yield= 80%) on oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in the presence of water. The conversion to aldehydes is promoted by electron-donating groups at the aromatic ring. On DDQ oxidation in the presence of methanol, methyl esters of cinnamic acids are the predominant products. DDQ oxidation of 1- or 3-(3,4-dimethoxyphenyl)-1-propene in the presence of acetic acid gives an acylal [the diacetate of (E)-3-(3,4-dimethoxyphenyl)-2-propene-1, 1-diol].
- Iliefski, Tommy,Li, Shiming,Lundquist, Knut
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p. 2413 - 2416
(2007/10/03)
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- Phase transfer Wittig reaction with 1,3-dioxolan-2-yl-methyltriphenyl phosphonium salts: An efficient method for vinylogation of aromatic aldehydes
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Aldehydes were efficiently transformed into allylic dioxolanes by a Wittig-type reaction, using 1,3-dioxolan-2-yl-methyltriphenylphosphonium bromide under phase transfer conditions. The substituent kinetic effects were studied, and related to Hammett values and electrochemical potentials.
- Daubresse, Nicolas,Francesch, Charlette,Rolando, Christian
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p. 10761 - 10770
(2007/10/03)
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- Synthesis of cinnamaldehydes by oxidation of arylpropenes with 2,3-dichloro-5,6-dicyanoquinone
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Alkoxylated 1-aryl-1-propenes [1-(4-methoxyphenyl)-1-propene, 1-(3,4-dimethoxyphenyl)-1-propene, 1-(3,4,5-trimethoxyphenyl)-1-propene] and 3-aryl-1-propenes [3-(4-methoxyphenyl)-1-propene, 3-(3,4-dimethoxyphenyl)-1-propene 3-(3,4,5-trimethoxyphenyl)-1-propene] gave cinnamaldehydes in 71-84% yield on treatment with 2,3-dichloro-5,6-dicyanoquinone (DDQ) (slight excess) at room temperature for 0.5-2 h in the two-phase system dichloromethane-water (4:1). Arylpropenes lacking electron-donating alkoxy groups (1-phenyl-1-propene, 3-phenyl-1-propene) or carrying an acetoxy group [1-(4-acetoxy-3-methoxyphenyl)-1-propene, 3-(4-acetoxy-3-methoxyphenyl)-1-propene] were converted into cinnamaldehydes in low to moderate yields on oxidation with a large excess of DDQ in combination with long reaction times (> 12 h). All the 1-aryl-1-propones examined were rapidly converted into a mixture of mono-and bis-(3-aryl-2-propenyl) ethers of 2,3-dichloro-5,6-dicyanohydroquinone (DDHQ) on DDQ oxidation. The rate of formation of DDHQ ethers from alkoxy-substituted 3-aryl-1-propenes was slightly lower. 3-Phenyl-1-propene and also 3-(4-acetoxy-3-methoxyphenyl)-1-propene were largely unchanged at the initial stage of the oxidation. Significant differences in the compositions of the DDHQ ether mixtures obtained from 1-aryl-1-propenes and 3-aryl-1-propones were not observed. Acta Chemica Scandinavica 1998.
- Iliefski, Tommy,Li, Shiming,Lundquist, Knut
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p. 1177 - 1182
(2007/10/03)
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- Synthesis of Alkylphenols and -catechols from Plectranthus albidus (Labiatae)
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In the preceding paper, we described the isolation and structure elucidation of a series of even-numbered phenol- or pyrocatechol-derived 1-arylalkane-5-ones.To establish the assigned structures unambiguously and to have larger quantities available for physiological testing, the following compounds were prepared: in the alkylphenol series, 1-(4'-hydroxyphenyl)tetradecan-5-one (2a), 1-(4'-hydroxyphenyl)hexadecan-5-one (2b), and 1-(4'-hydroxyphenyl)octadecan-5-one (2c); in the alkylcatechol series, 1-(3',4'-dihydroxyphenyl)decan-5-one (3a; not isolated as a natural compound), 1-(3',4'-dihydroxyphenyl)dodecan-5-one (3b), 1-(3',4'-dihydroxyphenyl)tetradecan-5-one (3c), 1-(3',4'-dihydroxyphenyl)hexadecan-5-one (3d), 1-(3',4'-dihydroxyphenyl)octadecan-5-one (3e), and 1-(3',4'-dihydroxyphenyl)icosan-5-one (3f); in the alkenylphenol series, (Z)-1-(4'-hydroxyphenyl)octadec-13-en-5-one (4a) and (E)-1-(4'-hydroxyphenyl)octadec-13-en-5-one (4b); in the alkenylcatechol series, (E,E)-1-(3',4'-dihydroxyphenyl)deca-1,3-dien-5-one (1) and (Z)-1-(3',4'-dihydroxyphenyl)octadec-13-en-5-one (5).All compounds proved to be identical with the previously assigned structures.Compound 1 was synthesized by regioselective aldol condensation of heptan-2-one with (E)-3-(3',4'-dimethoxyphenyl)prop-2-enal (6d; Scheme 1), the phenols 2a-c and the catechols 3a-f by addition of the corresponding alkyl Grignard reagent to 5-(4'-methoxyphenyl)- or 5-(3',4'-dimethoxyphenyl)pentanal (17c and 18c, resp.; Scheme 4), and the olefins 4a, 4b and 5 from 17c or 18c via the 9-O-silyl-protected 13-(4'-methoxyphenyl)- or 13-(3',4'-dimethoxyphenyl)tridecanals (26 and 27, resp.) and Wittig olefination as the key steps (Scheme 5).
- Buergi, Christoph,Liu, Gui,Rueedi, Peter
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p. 1901 - 1915
(2007/10/02)
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- CHEMISTRY OF ENOL ETHERS. LVI. CONDENSATION OF THE ACETALS OF AROMATIC ALDEHYDES WITH 1-ETHOXY-1,3-BUTADIENE. SYNTHESIS OF ARYLPOLYENE ALDEHYDES
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The condensation of a series of acetals of aromatic aldehydes (benzaldehyde, 4-methoxy and 3,4-dimethoxybenzaldehyde) with 1-ethoxy-1,3-butadiene was investigated.Successful realization of the reaction requires the presence of electron-donating goups in t
- Makin, S. M.,Shavrygina, O. A.,Dobretsova, E. K.,Ermakova, G. A.,Dymshakova, G. M.
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p. 651 - 656
(2007/10/02)
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