- A practical one-pot synthesis of coumarins in aqueous sodium bicarbonate via intramolecular Wittig reaction at room temperature
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An efficient, simple and relatively inexpensive method for the synthesis of coumarins in aqueous sodium bicarbonate at ambient temperature has been developed. It features an intramolecular Wittig reaction of substituted 2-formylphenyl 2-bromoacetate in saturated aqueous sodium bicarbonate. Its advantages include benign reaction conditions, easy work-up and good overall yield with short reaction time. Various substituted coumarins have been synthesized by utilizing this methodology. This journal is
- Belavagi, Ningaraddi S.,Deshapande, Narahari,Sunagar, Manjunath G.,Khazi, Imtiyaz Ahmed M.
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- Amine-catalyzed cascade synthesis of 3,4-diunsubstituted coumarins
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We disclose an efficient route to synthesize 3,4-diunsubstituted coumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes were tested, and the corresponding coumarin products were obtained in good to high yields under mild and metal-free reaction conditions. We disclose an efficient route to synthesize 3,4-diunsubstituted coumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes are tested, and the corresponding coumarin products are obtained in good to high yields under mild and metal-free reaction conditions. Copyright
- Wei, Jia,Wang, Pengcheng,Jia, Qianfa,Huang, Jiaoyao,Du, Zhiyun,Zhang, Kun,Wang, Jian
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- Tandem aldehyde-alkyne-amine coupling/cycloisomerization: A new synthesis of coumarins
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Cu-catalyzed A3 coupling of ethoxyacetylene, pyrrolidine and salicylaldehydes led to a concomitant cycloisomerization followed by hydrolysis of the resultant vinyl ether to afford coumarins in a cascade process. The reaction proceeded through exclusive 6-endo-dig cyclization and is compatible with halo and keto groups giving coumarins in good to moderate yields.
- Reddy, Maddi Sridhar,Thirupathi, Nuligonda,Haribabu, Madala
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- Gold(I)-Catalyzed Intramolecular Hydroarylation of Phenol-Derived Propiolates and Certain Related Ethers as a Route to Selectively Functionalized Coumarins and 2 H-Chromenes
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Methods are reported for the efficient assembly of a series of phenol-derived propiolates, including the parent system 56, and their Au(I)-catalyzed cyclization (intramolecular hydroarylation) to give the corresponding coumarins (e.g., 1). Simple syntheses of natural products such as ayapin (144) and scoparone (145) have been realized by such means, and the first of these subject to single-crystal X-ray analysis. A related process is described for the conversion of propargyl ethers such as 156 into the isomeric 2H-chromene precocene I (159), a naturally occurring inhibitor of juvenile hormone biosynthesis.
- Cervi, Aymeric,Vo, Yen,Chai, Christina L. L.,Banwell, Martin G.,Lan, Ping,Willis, Anthony C.
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p. 178 - 198
(2020/12/22)
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- Fe(III)-Catalyzed Decarboxylative C3-Difluoroarylmethylation of Coumarins with α,α-Difluoroarylacetic Acids
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A facile Fe(III)-catalyzed oxidative decarboxylative radical coupling reaction of α,α-difluoroarylacetic acids with coumarins has been developed. This transformation, which provides a series of C-3 difluoroarylmethylated coumarins containing various functional groups in moderate-to-good yields, features easily accessible starting materials and operational simplicity.
- Chen, Zhiwei,Bai, Xiang,Sun, Jie,Xu, Yicheng
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supporting information
p. 7674 - 7682
(2020/07/15)
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- Visible-light-induced regioselective alkylation of coumarins via decarboxylative coupling with N-hydroxyphthalimide esters
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An efficient photocatalytic decarboxylative 3-position alkylation of coumarins by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. A variety of NHP esters derived from aliphatic carboxylic acids (primary, secondary, and tertiary) has been proved to be tolerated for this decarboxylation process, affording a broad scope of 3-alkylated coumarin derivatives in moderate to excellent yields. This protocol was highlighted by its mild conditions, readily available starting materials, operational simplicity, and wide functional group tolerance.
- Jin, Can,Yan, Zhiyang,Sun, Bin,Yang, Jin
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supporting information
p. 2064 - 2068
(2019/04/11)
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- Iron-Catalyzed Regioselective Decarboxylative Alkylation of Coumarins and Chromones with Alkyl Diacyl Peroxides
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A facile iron-catalyzed decarboxylative radical coupling of alkyl diacyl peroxides with coumarins or chromones has been developed, affording a highly efficient approach to synthesize a variety of α-alkylated coumarins and β-alkylated chromones. The reaction proceeded smoothly without adding any ligand or additive and provided the corresponding products containing a wide scope of functional groups in moderate to excellent yields. This protocol was highlighted by its high regioselectivity, readily available starting materials, and operational simplicity.
- Jin, Can,Sun, Bin,Xu, Tengwei,Yan, Zhiyang,Zhang, Xun
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supporting information
p. 1585 - 1591
(2019/08/07)
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- Fabrication of an amyloid fibril-palladium nanocomposite: A sustainable catalyst for C-H activation and the electrooxidation of ethanol
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Amyloids are highly ordered nanofibrils and their tensile strength is similar to that of steel, which makes them resistant to extreme pH and temperature. Based on this rationale, we demonstrate a facile synthesis of palladium, copper, platinum, gold and silver nanocomposites using α-Synuclein (α-Syn) fibrils as a template. We showed that an α-Syn-fibril-palladium nanoparticles (α-Syn-PdNPs) composite can be used as a heterogeneous catalyst in C-H bond activation and the electrooxidation of ethanol. The study demonstrated α-Syn-PdNPs to be a superior heterogeneous catalyst for the synthesis of pharmaceutically valuable benzofuran, naphthofuran, coumarin and N-arylindole via C-H activation. Further, the electrooxidation of ethanol using α-Syn-PdNPs displayed an electrochemically active surface area of 160.6 m2 g-1, which is much higher than the previously reported values for supported Pd nanocomposites.
- Jayarajan, Ramasamy,Kumar, Rakesh,Gupta, Jagriti,Dev, Gayathri,Kadu, Pradeep,Chatterjee, Debdeep,Bahadur, Dhirendra,Maiti, Debabrata,Maji, Samir K.
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supporting information
p. 4486 - 4493
(2019/03/06)
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- Microwave-Assisted Synthesis of Phenylpropanoids and Coumarins: Total Synthesis of Osthol
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Herein we describe a one-pot microwave-assisted method for the synthesis of cinnamic acid and coumarin derivatives. The synthesis begins with an aldehyde synthon, and the chosen reaction conditions determine whether a cinnamic acid or coumarin derivative is formed. A regioselective Claisen rearrangement was also efficiently incorporated into the synthetic sequence to further increase the complexity of the product. Notably, this approach provides high product yields and selectivities without the need of a phenol protecting group.
- Konrádová, Daniela,Kozubíková, Hana,Dole?al, Karel,Pospí?il, Ji?í
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supporting information
p. 5204 - 5213
(2017/09/29)
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- Metal-free, Br?nsted acid-mediated synthesis of coumarin derivatives from phenols and propiolic acids
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A novel synthesis of coumarin derivatives by Br?nsted acid-mediated condensation and intramolecular cyclization of phenols and propiolic acids was reported. This transformation requires the use of TfOH in place of a conventional metal mediator, and it occurs under mild conditions and provides rapid access to coumarin derivatives in good yields.
- Choi, Hyuck,Kim, Jaehyun,Lee, Kooyeon
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supporting information
p. 3600 - 3603
(2016/07/21)
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- Process for preparing coumarin derivatives using phenol and propiolic acid
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Provided is a manufacturing method of coumarin derivative. The manufacturing method of coumarin derivative comprises a step of making a phenol compound react with a propiolic acid compound. According to the present invention, the manufacturing method of coumarin derivative is quick and efficient, and is useful to fields requiring synthesis of coumarin derivatives of various structures.COPYRIGHT KIPO 2016
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Paragraph 0125; 0126
(2017/01/12)
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- Cp?Co(III)-Catalyzed Annulations of 2-Alkenylphenols with CO: Mild Access to Coumarin Derivatives
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Cp?Co(III)-catalyzed annulations of 2-alkenylphenols with CO for the synthesis of coumarin derivatives have been developed. The reaction features mild reaction conditions, broad substrate scope, and good functional group tolerance. Preliminary mechanistic studies were conducted, suggesting that C-H activation is the turnover limiting step. Furthermore, the efficiency of this reaction was demonstrated by the rapid total synthesis of three natural products herniarin, xanthyletin, and seselin.
- Liu, Xu-Ge,Zhang, Shang-Shi,Jiang, Chun-Yong,Wu, Jia-Qiang,Li, Qingjiang,Wang, Honggen
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supporting information
p. 5404 - 5407
(2015/11/18)
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- Gold-catalyzed dearomative spirocyclization of aryl alkynoate esters
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Aryl alkynoate esters undergo gold-catalyzed spirocyclization under mild conditions, affording spirolactones in high yields. This approach obviates the need for stoichiometric halogenating reagents typically employed for alkyne activation in related trans
- Aparece, Mark D.,Vadola, Paul A.
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supporting information
p. 6008 - 6011
(2015/01/08)
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- Straightforward assembly of benzoxepines by means of a rhodium(III)- catalyzed C-H functionalization of o-vinylphenols
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Readily available o-vinylphenols undergo a formal (5 + 2) cycloaddition to alkynes when treated with catalytic amounts of [Cp*RhCl2] 2 and Cu(OAc)2. The reaction, which involves the cleavage of the terminal C-H bond of the alkenyl moiety, generates highly valuable benzoxepine skeletons in a practical, versatile, and atom-economical manner. Using carbon monoxide instead of an alkyne as reaction partner leads to coumarin products which formally result from a (5 + 1) cycloaddition.
- Seoane, Andres,Casanova, Noelia,Quinones, Noelia,Mascarenas, Jose L.,Gulias, Moises
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p. 834 - 837
(2014/02/14)
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- Palladium-catalyzed synthesis of benzofurans and coumarins from phenols and olefins
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Triple C-H functionalization: Palladium-catalyzed synthesis of benzofurans and coumarins by reacting phenols and unactivated olefins is described. The reaction comprises sequential C-H functionalization and shows diverse functional group compatibility. Preliminary mechanistic studies shed light into the possible mechanisms. Copyright
- Sharma, Upendra,Naveen, Togati,Maji, Arun,Manna, Srimanta,Maiti, Debabrata
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supporting information
p. 12669 - 12673
(2013/12/04)
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- Synthetic models related to methoxalen and menthofuran-cytochrome P450 (CYP) 2A6 interactions. Benzofuran and coumarin derivatives as potent and selective inhibitors of CYP2A6
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Human microsomal cytochrome P450 (CYP) 2A6 contributes extensively to nicotine detoxication but also activates tobacco-specific procarcinogens to mutagenic products. We prepared a series of benzofuran and coumarin derivatives that have inhibitory effects on the activity of human CYP2A6. The reported compounds methoxalen and menthofuran had potent inhibitory effects on the activity of CYP2A6 with IC50 values of 0.47 μM and 1.27 μM, respectively. Synthetic benzofuran (4-methoxybenzofuran: IC50=2.20 μM) and coumarin (5-methoxycoumarin: IC50=0.13 μM and 6-methoxycoumarin: IC50=0.64 μM) derivatives, which have more selective effects than those of methoxalen and menthofuran, exhibited comparable activities against CYP2A6. These compounds can be used as a lead compounds in the design of CYP2A6 inhibitor drugs to reduce smoking and tobacco-related cancers.
- Yamaguchi, Yuki,Akimoto, Ichie,Motegi, Kyoko,Yoshimura, Teruki,Wada, Keiji,Nishizono, Naozumi,Oda, Kazuaki
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p. 997 - 1001
(2013/11/19)
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- Synthesis of substituted coumarins and 2-quinolinones by cycloisomerisation of (hydroxy/aminophenyl)propargyl alcohols
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A new cycloisomerization strategy for the synthesis of coumarins and quinolinones is described. The addition of ethoxyacetylide to 2-hydroxyacetophenones directly resulted in 4-substituted coumarins by 6-endo-dig cycloisomerisation of the intermediate 3-ethoxy-1-(2-hydroxyphenyl)- 2-propyn-1-ols. Under similar conditions, 2-aminoacetophenone produced 2-ethoxyquinoline, a masked quinolinone, which was converted into the quinolinone by acid treatment. N-Protected intermediate 8 was isolated and converted into the quinolinone [with In(OTf)3 or H2SO 4] or the 3-iodo-2-quinolinone (with I2 and H +).
- Sridhar Reddy, Maddi,Thirupathi, Nuligonda,Babu, Madala Hari
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p. 5803 - 5809
(2012/11/07)
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- The Au(I)-catalyzed intramolecular hydroarylation of terminal alkynes under mild conditions: Application to the synthesis of 2H-chromenes, coumarins, benzofurans, and dihydroquinolines
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(Chemical Equation Presented) Operationally simple Au(I)-catalyzed intramolecular hydroarylation (IMHA) reactions of terminal alkynes that proceed in high yield and under very mild conditions are described. These processes involve low catalyst loadings, mild reaction temperatures, and short reaction times, require no cocatalysts or additives, and allow for the generation of a number of important heterocyclic motifs from readily accessible starting materials.
- Menon, Rajeev S.,Findlay, Alison D.,Bissember, Alex C.,Banwell, Martin G.
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supporting information; experimental part
p. 8901 - 8903
(2010/03/01)
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- A novel synthesis of coumarins employing triphenyl(α-carboxymethylene)phosphorane imidazolide as a C-2 synthon
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A novel one-pot synthesis of coumarins via intramolecular Wittig cyclization from the reaction of phenolic compounds containing ortho-carbonyl group and triphenyl(α-carboxymethylene)phosphorane imidazolide is described.
- Upadhyay, Puspesh K.,Kumar, Pradeep
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scheme or table
p. 236 - 238
(2009/05/11)
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- Synthesis and biological evaluation of alkoxycoumarins as novel nematicidal constituents
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We synthesized all of the monomethoxycoumarins, 5-alkoxycoumarins and their derivatives, and investigated their nematicidal activity against the phytopathogenic nematode, Bursaphelenchus xylophilus. Among the compounds, 5-ethoxycoumarin showed the highest nematicidal activity. Furthermore, 5-ethoxycoumarin was comparatively harmless against both the brine shrimps, Artemia salina, and the Japanese killifish, Oryzias latipes.
- Takaishi, Kazuto,Izumi, Minoru,Baba, Naomichi,Kawazu, Kazuyoshi,Nakajima, Shuhei
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supporting information; experimental part
p. 5614 - 5617
(2009/05/30)
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- Synthesis of coumarins by Pt-catalyzed hydroarylation of propiolic acids with phenols
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Synthesis of coumarins from phenols and propiolic acids was examined by using a Pt catalyst such as PtCl2/AgOTf, K2PtCl4/AgOTf, and K2PtCl4/AgOAc. Propiolic acid reacted even with less reactive phenols in trifluoroacetic acid to give coumarins and dihydrocoumarins. In the case of substituted propiolic acids, phenylpropiolic acid and 2-octynoic acid, the reactions proceeded selectively to afford coumarins in good to high yields.
- Oyamada, Juzo,Kitamura, Tsugio
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p. 6918 - 6925
(2007/10/03)
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- A convenient synthesis of coumarins by palladium(II)-catalyzed reaction of phenols with propiolic acids
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A direct route to coumarin derivatives from phenols and propiolic acids has been developed. Phenols react with propiolic acids in the presence of Pd(OAc)2 as a catalyst to give coumarins in good yields. The simple process occurs under mild conditions without any additives.
- Kotani, Masashi,Yamamoto, Kiyomi,Oyamada, Juzo,Fujiwara, Yuzo,Kitamura, Tsugio
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p. 1466 - 1470
(2007/10/03)
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- Synthesis of coumarins by ring-closing metathesis using Grubbs' catalyst
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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
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p. 4199 - 4201
(2007/10/03)
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- PdII-Catalyzed Reaction of Phenols with Propiolic Esters. A Single-Step Synthesis of Coumarins
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The intermolecular reaction of phenols with propiolic esters in TFA in the presence of a Pd(OAc)2 catalyst, affording coumarin derivatives, is described. An exclusive formation of 5,6,7-trimethoxy-4-phenylcoumarin was observed in the reaction of 3,4,5-trimethoxyphenol and ethyl phenylpropiolate with a catalytic amount of Pd(OAc)2. The reaction in the absence of Pd(OAc)2 did not give any coumarin at all. Coumarin derivatives were obtained in high yields in the cases of electron-rich phenols, such as 3,4-methylenedioxyphenol, 3-methoxyphenol, 2-naphthol, and 3,5-dimethoxyphenol. Furthermore, the reaction of some phenols with various 2-alkynoates or with diethyl acetylenedicarboxylate gave the corresponding coumarins in good-to-high yields.
- Kitamura, Tsugio,Yamamoto, Kiyomi,Kotani, Masashi,Oyamada, Juzo,Jia, Chengguo,Fujiwara, Yuzo
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p. 1889 - 1895
(2007/10/03)
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- Convenient synthesis of a simple coumarin from salicylaldehyde and wittig reagent. IV: Improved synthetic method of substituted coumarins
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The reaction of salicylaldehydes (2) with Horner-Wadsworth-Emmons (HWE) or Ando-HWE reagents was attempted to afford intramolecular phosphonate derivatives (6). A new synthetic method for coumarins (1) was achieved by using protected 2.
- Takeuchi, Yasuo,Ueda, Norihiro,Uesugi, Koji,Abe, Hitoshi,Nishioka, Hiromi,Harayama, Takashi
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p. 217 - 224
(2007/10/03)
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- CARBAPENEM DERIVATIVES CONTAINING A BICYCLIC KETONE SUBSTITUENT AND THEIR USE AS ANTI-INFECTIVES
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The present invention relates to carbapenems and provides a compound of the formula (I) wherein R1 is hydroxymethyl, 1-hydroxyethyl or 1-fluoroethyl; R2 is hydrogen or C1-4alkyl; X1 is oxygen or sulphur; and A is of the formula which is optionally substituted on either ring and wherein B is of the formula -CH2-C(=0)-(CH2)n-, -C(=0)-(CH2)n1-, -C(=0)-CH=CH-X2-, -C(=O)CH2CH2X2_(CH2)nC(=O)NH- or -CH=CHC(=O)NH wherein n is 1 or 2, n1 is 2 or 3 and X2 is NH, O or S; and a pharmaceutically acceptable salt or an in vivo hydrolysable ester thereof, processes for their preparation, intermediates in their preparation, their use as therapeutic agents and pharmaceutical compositions containing them
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- Carbapenem derivatives containing a bicyclic substituent, process for their preparation, and their use
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The present invention relates to carbapenems and provides a compound of the formula (I) wherein R1is hydroxymethyl, 1-hydroxyethyl or 1-fluoroethyl; R2is hydrogen or C1 4alkyl; X1is oxygen or sulphur; and Ais of the formula which is optionally substituted on either ring and wherein B is of the formula -CH2-C(=O)-(CH2)n-, -C(=O)-(CH2)n1-, -C(=O)-CH=CH-X2-, -C(=O)CH2CH2X2-, -(CH2)nC(=0)NH- or -CH=CHC(=O)NH- wherein n is 1 or 2, n1 is 2 or 3 and X2 is NH, 0 or S; and a pharmaceutically acceptable salt or an in vivohydrolysable ester thereof, processes for their preparation, intermediates in their preparation, their use as therapeutic agents and pharmaceutical compositions containing them.
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- A Convenient Synthesis of a Simple Coumarin from Salicylaldehyde and Wittig Reagent (I): A Synthesis of Methoxy- and Hydroxycoumarins
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Reaction of methoxy- and hydroxysalicylaldehydes (1) with phosphorane in diethylaniline under reflux gave only coumarins (3) in high yields except for 3-methoxysalicylaldehyde (1b).It was clarified that methoxy group(s) at C4 and C6 on 1 facilitated the formation of 3.
- Harayama, Takashi,Katsuno, Keiko,Nishioka, Hiromi,Fujii, Masako,Nishita, Yoshitaka,et al.
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p. 613 - 622
(2007/10/02)
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- A convenient synthesis of a simple coumarin
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Reaction of salicylaldehydes (1) with carbethoxymethylenephosphorane in diethylaniline under reflux gave coumarins (3) in excellent yields. Methoxy substituent at C'4 on salicylaldehyde (1) facilitated the formation of coumarin from trans-cinnamate (2), which is first prepared by reaction of 1 with Wittig reagent.
- Ishii,Kaneko,Miyazaki,Harayama
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p. 3100 - 3102
(2007/10/02)
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- Enolethers, XVIII. - A Simple Synthesis of Coumarins
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In boiling 1,2-dichloroethane 3-ethoxyacryloyl chloride (1) reacts with phenols 2 to yield 3-ethoxyacrylates 3, which by treatment with conc. sulfuric acid/10percent SO3 cyclize to give coumarins 9 in good yields.The methoxy-substituted compounds 3d and 3k do not react to coumarins 9 with H2SO4/SO3 but with POCl3/H2O at room temperature.
- Ziegler, Thomas,Moehler, Hans,Effenberger, Franz
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p. 373 - 378
(2007/10/02)
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- Selective ortho-Alkylation of Phenols with Sulphoxides via Sigmatropic Rearrangement: Synthesis of Coumarins
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ortho-Alkylphenols have been prepared from phenol and dialkyl sulphoxides via sigmatropic rearrangement, using thionyl chloride or phenyl chlorosulphinate as an activator of sulphoxides.In the same manner, ortho-phenylthiomethylphenol has been prepared in good yields.When ethyl phenyl sulphoxide, diallyl sulphoxide, and methyl methylsulphinylacetate were used as sulphoxides, none of the expected products were obtained.Salicylaldehyde has been prepared in moderate yield, when methyl methylthiomethyl sulphoxide was used as a sulphoxide. 3-(2-Hydroxyphenyl)propionic acid derivatives, which were obtained from substituted phenols and dimethyl 3,3'-sulphynyldipropionate, have been cyclized to give the corresponding coumarins in good yields.
- Sato, Kikumasa,Inoue, Seiichi,Ozawa, Kimio,Kobayashi, Tohru,Ota, Tomomi,Tazaki, Michiko
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p. 1753 - 1756
(2007/10/02)
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