- Harnessing Thorpe–Ingold Dialkylation to Access High-Hill-Percentage pH Probes
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Sensitivity is an important parameter for a molecular probe. Hill-type pH probes exhibit improved detection sensitivity compared to the traditional pH probes following the Henderson–Hasselbalch equation. Exploiting positive cooperativity, we recently devised a novel molecular scaffold (PHX) to offer such an unconventional Hill-type pH titration profile. We previously confirmed that PHX is not a pure Hill-type probe yet. Only 64% of its absorbance/fluorescence turn-on is the result of a Hill-type pathway. The remaining 36% is from an undesired Henderson–Hasselbalch-type pathway (HH pathway). In this work, the Thorpe–Ingold dialkylation was harnessed to further suppress the percent contribution of the HH pathway down to 16%. We also propose that PHX is a viable molecular model for assessing the efficacy of the steric compressing effect induced by different Thorpe–Ingold dialkylations.
- Huang, Yunxia,Luo, Xiao,Qian, Xuhong,Xiao, Yansheng,Yang, Youjun,Zeng, Zhenhua
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- Microwave accelerated the solvent-free synthesis of 4-aryl-3,4-dihydrocoumarin via the tandem reaction of cinnamic acids with phenols catalyzed by Amberlyst 15 resin
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Amberlyst 15 resin supported the tandem reaction of cinnamic acids with phenols under solvent-free reaction condition has been introduced to afford 4-aryl-3,4-dihydrocoumarin (neoflavanone) derivatives. The efficiency of solid acidic sulfonic resin (A-15) has been illustrated in two reaction activation methods such as microwave irradiation and conventional heating. The important roles of Amberlyst 15 have been emphasized strongly through the high yields of 4-aryl-3,4-dihydrocoumarin in the shorter time under the assistance of microwave irradiation than of conventional heating, and its high recovery and reusability for six catalyst runs. The original catalyst as well as the recycled catalyst were characterized by XRD and FE-SEM to study the correlation of the surface of reused catalyst and its recyclability.
- Le, Huu-Phuoc,Duong, Cong-Thang,Nguyen, Xuan-Triet,Luu, Thi Xuan Thi
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p. 2187 - 2203
(2021/07/02)
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- Ir-catalyzed asymmetric hydrogenation of 3-arylindenones for the synthesis of chiral 3-arylindanones
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An efficient synthesis of chiral 3-arylindanones via iridium-catalyzed asymmetric hydrogenation of 3-arylindenones has been developed. The reaction showed good compatibility with various functional groups, delivering a variety of 3-arylindanones in excellent yields and with good enantioselectivities. The reaction was also carried out on a gram-scale, delivering the product in quantitative yield. In addition, the products can be easily derivatized and transformed into natural products and pharmaceutical agents.
- Yan, Jun,Nie, Yu,Gao, Feng,Yuan, Qianjia,Xie, Fang,Zhang, Wanbin
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supporting information
(2021/02/27)
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- Asymmetric Hydroesterification of Diarylmethyl Carbinols
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An efficient asymmetric hydroesterfication of diarylmethyl carbinols is developed for the first time with a Pd-WingPhos catalyst, resulting in a series of chiral 4-aryl-3,4-dihydrocoumarins in excellent enantioselectivities and good yields. The method features mild reaction conditions, a broad substrate scope, use of easily accessible starting materials, and low palladium loadings. A plausible stereochemical model is also proposed with the Pd-WingPhos catalyst. This method has enabled a 4-step asymmetric synthesis of (R)-tolterodine from readily available starting materials.
- Tian, Duanshuai,Xu, Ronghua,Zhu, Jinbin,Huang, Jianxun,Dong, Wei,Claverie, Jerome,Tang, Wenjun
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p. 6305 - 6309
(2021/02/09)
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- Organic Br?nsted acid-catalyzed cycloadditions of o-quinone methides with 1, 3-dicarbonlys: Facile access to xanthenones and chromanones
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The in-situ generation of o-quinone methides and their inverse-electron-demand Diels–Alder reaction in the presence of pentacarboxycyclopentadiene—an organic Br?nsted acid—has been reported. The synthesis of xanthenones and chromanones in good to excellen
- Kokkuvayil Vasu, Radhakrishnan,Parameswaran, Sasikumar,Puthiyaparambath, Sharathna,Suresh Varma, Sanjay,Thoppe Sivakumar, Priyadarshini
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- Palladium Nanoparticles-Catalyzed Synthesis of Indanone Derivatives via Intramolecular Reductive Heck Reaction
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An efficient protocol for the straightforward, single-step synthesis of 3-aryl-1-indanones from 2′-iodochalcone via reductive Heck reaction using phosphine free, stable and reusable binaphthyl stabilized palladium nanoparticle (Pd-BNP) as a catalyst has been described. An immense array of substrate scope with electron-rich and deficient 2′-iodochalcones have been synthesized. Further derivatization of product indanones have been achieved successfully. The heterogeneous nature of the Pd-BNP has been validated by centrifugation test and mercury poisoning experiment. Pd-BNP has been successfully recycled up to 5 cycles without any significant loss in reaction yield and particle size of nanoparticles, confirmed by TEM analysis. (Figure presented.).
- Parveen, Naziya,Sekar, Govindasamy
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p. 4581 - 4595
(2019/09/03)
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- Organocatalyst-Mediated Dynamic Kinetic Enantioselective Acylation of 2-Chromanols
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We recently developed a novel chiral catalyst-directed dynamic kinetic diastereoselective acylation of hemiacetals for the synthesis of carbohydrates. In this update, we describe a catalytic method for the dynamic kinetic enantioselective acylation of 2-c
- Glazier, Daniel A.,Schroeder, John M.,Liu, Jitian,Tang, Weiping
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supporting information
p. 4646 - 4649
(2018/11/10)
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- The second-generation synthesis of BICMAP analogues
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We previously reported the synthesis of BICMAP (1a) via 6-diphenylphosphino-2,3-dihydrobenzofuran as a key intermediate. However, we did not successfully synthesize BICMAP analogues via a similar synthetic route. Herein we report the second-generation syn
- Mino, Takashi,Watanabe, Kohei,Akiyama, Takumu,Mizutani, Yuki,Miura, Kazuki,Hashimoto, Masatoshi,Yoshida, Yasushi,Sakamoto, Masami
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p. 3871 - 3878
(2018/06/06)
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- Hexafluoroisopropanol and Acetyl Chloride Promoted Catalytic Hydroarylation with Phenols
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We report a catalytic hydroarylation method to convert phenols to dihydrocoumarins in hexafluoroisopropanol (HFIP) using acid generated from sub-stoichiometric amounts of acetyl chloride as catalyst. Attractive elements include easy set-up and isolation, and applicability to a range of phenols including natural product substrates.
- Roy, Sudeshna,Motiwala, Hashim F.,Koshlap, Karl M.,Aubé, Jeffrey
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supporting information
p. 306 - 315
(2017/12/07)
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- Hydroarylation of cinnamic acid with phenols catalyzed by acidic ionic liquid [H-NMP]HSO4: computational assessment on substituent effect
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Hydroarylation of cinnamic acid with different substituted phenols, in the presence of acidic ionic liquid, N-methyl-2-pyrrolidonum hydrosulfate ([H-NMP]HSO4) gave the corresponding dihydrocoumarins in high yields and excellent selectivity. Amo
- Zadsirjan, Vahideh,Heravi, Majid M.,Tajbakhsh, Mahmoud,Oskooie, Hossein A.,Shiri, Morteza,Hosseinnejad, Tayebeh
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p. 6407 - 6422
(2016/07/06)
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- Single-step synthesis of 4-phenyl and 3,4-dihydro-4-phenyl coumarins using a recyclable Preyssler heteropolyacid catalyst under solvent-free reaction conditions
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4-Phenyl and 3,4-dihydro-4-phenylcoumarins were prepared by direct esterification of phenols with phenylpropiolic and cinnamic acids, respectively, using a compound with Preyssler structure (H14P5NaW30O110) (PA)
- Escobar, Anglica M.,Ruiz, Diego M.,Autino, Juan C.,Romanelli, Gustavo P.
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p. 10109 - 10123
(2016/01/12)
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- A palladium-catalyzed enantioselective hydroesterification of alkenylphenols with phenyl formate. A facile approach to optically active dihydrocoumarins
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An effective palladium-catalyzed enantioselective hydroesterification of alkenylphenols with phenyl formate as a CO source is described. A variety of optically active dihydrocoumarins can be obtained in generally high yields with up to 91% ee.
- Li, Jingfu,Chang, Wenju,Ren, Wenlong,Liu, Wei,Wang, Haining,Shi, Yian
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supporting information
p. 10341 - 10347
(2015/10/28)
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- Catalytic Asymmetric Addition of Meldrum's Acid, Malononitrile, and 1,3-Dicarbonyls to ortho-Quinone Methides Generated In Situ under Basic Conditions
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A new approach to the utilization of highly reactive and unstable ortho-quinone methides (o-QMs) in catalytic asymmetric settings is presented. The enantioselective reactions are catalysed by bifunctional organocatalysts, and the o-QM intermediates are formed in situ from 2-sulfonylalkyl phenols through base-promoted elimination of sulfinic acid. The use of mild Bronsted basic conditions for transiently generating o-QMs in catalytic asymmetric processes is unprecedented, and allows engaging productively in the reactions nucleophiles such as Meldrum's acid, malononitrile and 1,3-dicarbonyls. The catalytic transformations give new and general entries to 3,4-dihydrocoumarins, 4H-chromenes and xanthenones. These frameworks are recurring structures in natural product and medicinal chemistry, as testified by the formal syntheses of (R)-tolterodine and (S)-4-methoxydalbergione from the catalytic adducts.
- Caruana, Lorenzo,Mondatori, Martina,Corti, Vasco,Morales, Sara,Mazzanti, Andrea,Fochi, Mariafrancesca,Bernardi, Luca
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supporting information
p. 6037 - 6041
(2015/04/14)
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- BICMAP-rhodium(I)-catalyzed asymmetric 1,4-addition of arylboronic acids to coumarins
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Rhodium(I)-catalyzed asymmetric 1,4-addition of arylboronic acids 2 to coumarins 1 using (S)-BICMAP as a chiral ligand gave the desired 4-arylchroman-2-one derivatives 2 in good yields and with high enantioselectivities (up to 99% ee).
- Mino, Takashi,Miura, Kazuki,Taguchi, Hiroyuki,Watanabe, Kohei,Sakamoto, Masami
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p. 1065 - 1068
(2015/10/19)
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- Imidazole derivatives as accelerators for ruthenium-catalyzed hydroesterification and hydrocarbamoylation of alkenes: Extensive ligand screening and mechanistic study
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Imidazole derivatives are effective ligands for promoting the [Ru3(CO)12]-catalyzed hydroesterification of alkenes using formates. Extensive ligand screening was performed to identify 2-hydroxymethylated imidazole as the optimal ligand. Neither carbon monoxide gas nor a directing group was required, and the reaction also showed a wide substrate generality. The Ru-imidazole catalyst system also promoted intramolecular hydrocarbamoylation to afford lactams. A Ru-imidazole complex was unambiguously analyzed by X-ray crystallography, and it had a trinuclear structure derived from one [Ru3(CO)12] and two ligands. This complex was also successfully used for hydroesterification. The mechanism was examined in detail by using D- and 13C-labeled formates, indicating that the hydroesterification reaction proceeds by a decarbonylation-recarbonylation pathway. Effective imidazole assistant: [Ru3(CO)12]-catalyzed hydroesterification of alkenes by using formates is drastically accelerated by imidazole derivatives and exhibits a broad substrate scope for both alkenes and formates. The Ru-imidazole complex also catalyzes the intramolecular hydrocarbamoylation of alkenes.
- Konishi, Hideyuki,Muto, Takashi,Ueda, Tsuyoshi,Yamada, Yayoi,Yamaguchi, Miyuki,Manabe, Kei
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p. 836 - 845
(2015/03/14)
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- Molecular iodine catalyst promoted synthesis of chromans and 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling
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Molecular iodine as an inexpensive catalyst is described in the construction of 2-substituted or 2,2-disubstituted chromans and 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling. For the synthesis of chromans, phenols and allylic alcohols were refluxed in chloroform in presence of 20 mol % I2 while [3+3] cyclocoupling of phenols and cinnamic acids proceeded to give 4-aryl-3,4-dihydrobenzopyran-2-ones using 30 mol % I2. Later reaction occurs via a tandem hydroarylation- esterification process at 120-130°C under solvent free conditions. Chromans were obtained in 20-92% yields and substituted 4-aryl-3,4-dihydrobenzopyran-2- ones were obtained in 5-85% yields.
- Naik, Mayuri M.,Kamat, Durga P.,Tilve, Santosh G.,Kamat, Vijayendra P.
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p. 5221 - 5233
(2014/07/08)
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- Molecular iodine catalyst promoted synthesis of chromans and 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling
-
Molecular iodine as an inexpensive catalyst is described in the construction of 2-substituted or 2,2-disubstituted chromans and 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling. For the synthesis of chromans, phenols and allylic alcohols were refluxed in chloroform in presence of 20 mol % I2while [3+3] cyclocoupling of phenols and cinnamic acids proceeded to give 4-aryl-3,4-dihydrobenzopyran-2-ones using 30 mol % I2. Later reaction occurs via a tandem hydroarylation-esterification process at 120-130 °C under solvent free conditions. Chromans were obtained in 20-92% yields and substituted 4-aryl-3,4-dihydrobenzopyran-2-ones were obtained in 5-85% yields.
- Naik, Mayuri M.,Kamat, Durga P.,Tilve, Santosh G.,Kamat, Vijayendra P.
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p. 5221 - 5233
(2014/12/10)
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- Lewis acid promoted dual bond formation: Facile synthesis of dihydrocoumarins and spiro-tetracyclic dihydrocoumarins
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Lewis acid (FeCl3) mediated dual bond (C-C and C-O) formation for synthesis of 3,4-dihydrocoumarins is presented. This method has successfully delivered a number of dihydrocoumarins containing dense functionalities on the aromatic ring. Significantly, the present method enabled achieving dihydrocoumarins with tertiary as well as quaternary carbon atoms at the benzylic position. Gratifyingly, the novel spiro-tetracyclic lactones have also been dextrously prepared using this process. the Partner Organisations 2014.
- Niharika, Pedireddi,Ramulu, Bokka Venkat,Satyanarayana, Gedu
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p. 4347 - 4360
(2014/06/23)
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- A palladium-catalyzed regioselective hydroesterification of alkenylphenols to lactones with phenyl formate as CO source
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An effective Pd(OAc)2-PPh3 catalyzed hydroesterification of alkenylphenols with phenyl formate as CO surrogate is described. A variety of lactones are obtained in generally high yields with high regioselectivities. In one case, 76% ee is obtained with a chiral ligand.
- Wang, Haining,Dong, Ben,Wang, Yang,Li, Jingfu,Shi, Yian
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supporting information
p. 186 - 189
(2014/01/23)
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- Solvent-free synthesis of 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling of phenols with cinnamic acid catalyzed by molecular iodine
-
Molecular iodine was used as a catalyst in the [3+3] cyclocoupling of phenols and cinnamic acids which proceeds via a tandem esterification- hydroarylation process at 120-130 °C under solvent-free conditions. Substituted 4-aryl-3,4-dihydrobenzopyran-2-one
- Kamat, Durga P.,Tilve, Santosh G.,Kamat, Vijayendra P.
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experimental part
p. 4469 - 4472
(2012/09/22)
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- Remarkable improvement achieved by imidazole derivatives in ruthenium-catalyzed hydroesterification of alkenes using formates
-
Imidazole derivatives are revealed to be effective ligands in the Ru-catalyzed hydroesterification of alkenes using formates, affording one-carbonelongated esters in high yields. Further, intramolecular hydroesterification was successfully performed to give lactones for the first time. Imidazole derivatives can contribute to promote the reaction as well as to suppress the undesired decarbonylation of formate. Toxic CO gas, a directing group, and large excess alkenes are not required.
- Konishi, Hideyuki,Muto, Takashi,Manabe, Kei,Ueda, Tsuyoshi
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supporting information
p. 4722 - 4725,4
(2012/12/12)
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- TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes: A novel method for the solid-phase synthesis of dihydrocoumarins and coumarins
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TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succinimidyl selenide as the selenium source. This catalytic process provides an efficient method for the regioselective synthesis of dihydrocoumarins possessing a seleno-functionality, followed by traceless cleavage of selenium linker to provide dihydrocoumarins and coumarins in good yields and purities.
- Tang,Li, Wen,Gao, Zhang Yong,Gu, Xi
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experimental part
p. 631 - 634
(2012/07/03)
-
- Palladium-catalyzed oxidative heck coupling reaction for direct synthesis of 4-arylcoumarins using coumarins and arylboronic acids
-
An efficient protocol for the direct synthesis of 4-arylcoumarins via palladium-catalyzed oxidative Heck coupling reaction of coumarins and arylboronic acids was developed. 4-Arylcoumarins were obtained in moderate to excellent yields, and the reaction also showed tolerance toward functional groups such as hydro, methoxy, diethylamino, nitro, and chloro groups.
- Li, Yaming,Qi, Zisong,Wang, Huifeng,Fu, Xinmei,Duan, Chunying
-
supporting information; experimental part
p. 2053 - 2057
(2012/04/04)
-
- Selective synthesis of 3,4-dihydrocoumarins and chalcones from substituted aryl cinnamic esters
-
Coumarins are ubiquitous in plant kingdom and have been used as antitumor, antifungals, anticoagulants, insecticides. Chalcones are also widespread in plant kingdom and have been known to possess diverse biological activities; antibacterial, antifungal, antitumor and anti-inflammatory, etc. As they are considered as important natural products, numerous synthetic approaches have been reported up to the present. We devise a new selective method of preparing dihydrocoumarins and chalcones from aryl cinnamates by the selection of reagents. Dihydrocoumarin derivatives were prepared selectively by using intramolecular cyclization catalyzed by p-toluene sulfonic acid. Also, chalcones were prepared by Fries-rearrangement catalyzed by TiCl4. This method can be used for preparing various coumarin & chalcone compounds.
- Jeon, Jae-Ho,Yang, Deok-Mo,Jun, Jong-Gab
-
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- Copper-catalyzed asymmetric 1,4-hydroboration of coumarins with pinacolborane: Asymmetric synthesis of dihydrocoumarins
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An efficient asymmetric addition of pinacolborane to 4-substituted coumarins proceeded with high enantioselectivity in the presence of a copper(I)-QuinoxP complex as a catalyst to produce the corresponding 1,4-hydroboration products. Treatment of the intermediates with electrophiles, without isolation, resulted in enantioenriched dihydrocoumarins. The utility of this protocol was demonstrated in the formal synthesis of biologically active molecules.
- Kima, Hyohyun,Yuna, Jaesook
-
scheme or table
p. 1881 - 1885
(2010/10/20)
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- Rhodium-catalyzed domino conjugate addition-cyclization reactions for the synthesis of a variety of N- and O-heterocycles: Arylboroxines as effective carbon nucleophiles
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Facile and efficient Rh(I)-catalyzed domino conjugate addition-cyclization reactions of olefins bearing two electrophilic sites and a pendant nucleophile with organoboroxines have been developed to afford a variety of N- and O-heterocycles, such as 3,4-dihydroquinolin-2(1H)-ones, 3,4-dihydrocoumarins, and pyrrolidin-2-ones, which constitute important motifs in biologically active natural and synthetic organic compounds.
- Park, Ja Ock,Youn, So Won
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supporting information; experimental part
p. 2258 - 2261
(2010/07/17)
-
- Direct oxidative cyclization of 3-arylpropionic acids using PIFA or Oxone: synthesis of 3,4-dihydrocoumarins
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The direct oxidative cyclization of 3-arylpropionic acids using PIFA or Oxone is reported. In the presence of BF3·OEt2, the reaction of 3-arylpropionic acids with PIFA or Oxone proceeded smoothly at 30 °C to give 3,4-dihydrocoumarins
- Gu, Yonghong,Xue, Kun
-
supporting information; experimental part
p. 192 - 196
(2010/03/04)
-
- Microwave-assisted one-pot synthesis of dihydrocoumarins from phenols and cinnamoyl chloride
-
A facile approach has been developed for the synthesis of dihydrocoumarin derivatives through the reaction of phenols and cinnamoyl chloride in the presence of ecofriendly solid-acid catalyst montmorillonite K-10 via a tandem esterification-Friedel-Crafts
- Zhang, Zhen,Ma, Yuan,Zhao, Yufen
-
experimental part
p. 1091 - 1095
(2009/04/04)
-
- p-Toluenesulfonic acid mediated hydroarylation of cinnamic acids with anisoles and phenols under metal and solvent-free conditions
-
Hydroarylation of cinnamic acids with anisoles and phenols mediated by p-toluenesulfonic acid (p-TSA) under metal and solvent-free conditions gave 3-(4-methoxyphenyl)-3-phenylpropanoic acids and dihydrocoumarins, respectively, in high yields and excellent selectivity.
- Jagdale, Arun R.,Sudalai, Arumugam
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p. 4895 - 4898
(2008/02/08)
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- Enantioselective synthesis of 3-arylindan-1-ones via intramolecular C-H insertion reactions of -diazo--ketoesters catalyzed by chiral dirhodium(II) carboxylates
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A new, catalytic enantioselective route to 3-arylindan-1-ones, versatile intermediates for the synthesis of a number of bioactive and pharmaceutically interesting molecules, was developed by exploiting the chiral dirhodium(II) complex-catalyzed intramolec
- Natori, Yoshihiro,Anada, Masahiro,Nakamura, Seiichi,Nambu, Hisanori,Hashimoto, Shunichi
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p. 635 - 646
(2008/02/02)
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- Chiral [2.2.2] dienes as ligands for Rh(I) in conjugate additions of boronic acids to a wide range of acceptors
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We document a series of investigations that led to new substituted [2.2.2]-diene ligands which display high selectivity in Rh(I)-catalyzed conjugate addition reactions to substrates not previously examined with diene ligands. Moreover, we disclose an unexpected, interesting effect that results from the introduction of a third C=C onto the ligand scaffold (cf. 1).
- Defieber, Christian,Paquin, Jean-Francois,Serna, Sonia,Carreira, Erick M.
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p. 3873 - 3876
(2007/10/03)
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- An efficient synthesis of neoflavonoid antioxidants based on Montmorillonite K-10 catalysis
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A new approach to synthesis of neoflavonoids, based on a high yielding Montmorillonite K-10 catalyzed lactone ring forming cyclization process, is described. The utility of this methodology is exemplified by its employment in the preparation of the substituted 4-phenylneoflavonoids 1-8. The free radical scavenging properties of these substances were evaluated. The neoflavonoids 1 and 5, which mimic esculetin-type antioxidants, were observed to quench hydrazyl free radicals.
- Lee,Tseng,Lee
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p. 2247 - 2254
(2007/10/03)
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- The reactions of phenols with α,β-unsaturated aromatic acids in presence of polyphosphoric acid: Synthetic and mechanistic studies
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The reactions of cinnamic acid with phenol itself, catechol, hydroquinone, pyrogallol and 2-naphthol in presence PPA were studied and that with resorcinol was reinvestigated. With phenol itself and hydroquinone were obtained 3,4-dihydro-4-phenylcoumarin (1r) and 6-hydroxy-3,4-dihydro-4-phenylcoumarin (1s), respectively, as the sole products. Catechol and pyrogallol, on the other hand, afforded, besides the corresponding 3,4-dihydrocoumarins, viz. 8-hydroxy-3,4-dihydro-4-phenylcoumarin (1t) and 7,8-dihydroxy-3,4-dihydro-4-phenylcoumarin (1u), as the major products, 5,6-dihydroxy-3-phenylindanone (5b) and the chalcone 1-(2′,3′,4′-trihydroxy)-3-phenylpropan-2-en-1-one (3d), respectively, as minor products. But contrary to earlier observation, resorcinol was found to give 7-hydroxy-3,4-dihydro-4-phenylcoumarin (1v) instead of 7-hydroxyflavanone (4e). 2-Naphthol, on the other hand, afforded the chalcone derivative 1-|2′-hydroxynaphthyl|-3-phenylpropan-2-ene-1-one (7) as the exclusive product. The yields of the major products in the above reactions were 50-67% except that with phenol itself yielding 1r in 40% yield. The structures of all the products 1r, 1s, 1t, 1u, 1v, 3d, 5b and 7 were established from their various spectral (IR, 1H and 13C NMR and mass) data. Evidence for plausible mechanisms of formation of the above products was provided.
- Majumder,Chatterjee,Mukhoti
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p. 743 - 755
(2007/10/03)
-
- Synthesis of substituted (±)-3,4-dihydrocoumarins using H-Y zeolite
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Synthesis of substituted (±)-3,4 Dihydrocoumarins were prepared with the reaction between substituted cinnamic acid and phenol catalysed by eco- friendly solid-acid catalyst H-Y zeolite involving esterification followed by ring closure.
- Shukla, Manojkumar R.,Patil, Prashant N.,Wadgaonkar, Prakash P.,Joshi, Prafulla N.,Salunkhe, Manikrao M.
-
-
- Synthesis and structural elucidation of (±)-3,4-dihydrocoumarins by 2D- NOESY spectrum
-
(±)-3,4-Dihydrocoumarins have been synthesized in high yield and the structures are confirmed by 2D-NOESY spectrum.
- Shukla,Padiya,Patil,Salunkhe
-
p. 372 - 375
(2007/10/03)
-
- Highly Efficient and Single Step Synthesis of 4-Phenylcoumarins and 3,4-Dihydro-4-phenylcoumarins over Montmorillonite K-10 Clay, under Microwave Irradiation
-
A simple, elegant and one-pot synthesis of 3,4-dihydro-4-phenylcoumarins, 4-phenylcoumarins and their derivatives by making use of solid support, montmorillonite K-10 clay in conjunction with microwave irradiation is described.
- Singh, Jasvinder,Kaur, Jasamrit,Nayyar, Sandeep,Kad, Goverdhan L.
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p. 280 - 281
(2007/10/03)
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- Palladium in organic synthesis: Part IV-Palladium (0) catalyzed arylation of coumarin
-
Palladium (0)-catalyzed insertion of bromobenzene and 4-bromoanisole to coumarin affords 3-arylcoumarins (2) and 4-aryl-3,4-dihydrocoumarins (3).
- Mitra, Jayati,Mitra, Alok Kumar
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p. 588 - 589
(2007/10/03)
-
- α, β-Unsaturated N-Acylureas as Useful Intermediates for the Synthesis of Indanones, Chromanones and Coumarins
-
α,β-Unsaturated N-acylureas, viz-N-formamido-2-butenamide (I), N-formamido-3-methyl-2-butenamide (II) and N-formamido-3-phenyl-2-propenamide (III) react with aryl alkyl ethers in the presence of PPA to afford the corresponding crotonophenones and chalcones (IV) at lower temperature and 1-indanones (V) at a higher temperature.Reactions of I and II with phenols in the presence of PPA afford the 4-chromanones (VI), while III gives 3,4-dihydro-4-phenylcoumarins (VII) in excellent yields.
- Ramana, M. M. V.,Kudav, N. A.
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p. 339 - 341
(2007/10/02)
-