- Acid activated montmorillonite K-10 mediated intramolecular acylation: Simple and convenient synthesis of 4-chromanones
-
3-Aryloxyproionic acids undergo intramolecular cyclization in the presence of AA.Mont.K-10 in toluene under reflux for 30–45 min in good to excellent yields. Phenyl ring bearing various substituents at the ortho, meta, para positions undergo this cyclization reaction. This method involves simple work up and amenable for large scale preparations. The heterogeneous acid treated catalyst can be regenerated and used for up to three cycles with minimum loss of activity.
- Begum, Ayisha F.,Balasubramanian, Kalpattu K.,Shanmugasundaram, Bhagavathy
-
-
- Synthesis and anti-inflammatory activity of 2-oxo-2H-chromenyl and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates
-
Cycloaddition reaction of 4-chloro-2-oxo-2H-chromene-3-carbaldehydes (3a-g) and 4-chloro-2H-chromene-3-carbaldehydes (7a-h) with activated alkynes (4a-b) provided the 2-oxo-2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (5a-n) and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (8a-p). All the prepared compounds were screened for anti-inflammatory activity. In vitro anti-inflammatory activity data demonstrated that the compounds 5g, 5i, 5k-l and 8f are effective among the tested compounds against TNF-α (1.108 ± 0.002, 0.423 ± 0.022, 0.047 ± 0.001, 0.070 ± 0.002 and 0.142 ± 0.001 μM) in comparison with standard compound Prednisolone (0.033 ± 0.002 μM). Based on in vitro results, three compounds (5i, 5k and 8f) have been selected for in vivo experiments and these compounds are identified as better compounds with respect to anti-inflammatory activity in LPS induced mice model. Compound 5i was identified as potent and showed significant reduction in TNF-α and IL-6.
- Bhimapaka, China Raju,Karri, Shailaja,Kuncha, Madhusudana,Kurma, Siva Hariprasad,Sistla, Ramakrishna
-
-
- Redox-Neutral Coupling between Two C(sp3)?H Bonds Enabled by 1,4-Palladium Shift for the Synthesis of Fused Heterocycles
-
The intramolecular coupling of two C(sp3)?H bonds to forge a C(sp3)?C(sp3) bond is enabled by 1,4-Pd shift from a trisubstituted aryl bromide. Contrary to most C(sp3)?C(sp3) cross-dehydrogenative couplings, this reaction operates under redox-neutral conditions, with the C?Br bond acting as an internal oxidant. Furthermore, it allows the coupling between two moderately acidic primary or secondary C?H bonds, which are adjacent to an oxygen or nitrogen atom on one side, and benzylic or adjacent to a carbonyl group on the other side. A variety of valuable fused heterocycles were obtained from easily accessible ortho-bromophenol and aniline precursors. The second C?H bond cleavage was successfully replaced with carbonyl insertion to generate other types of C(sp3)-C(sp3) bonds.
- Rocaboy, Ronan,Anastasiou, Ioannis,Baudoin, Olivier
-
supporting information
p. 14625 - 14628
(2019/09/16)
-
- Synthesis of Flavanones via Palladium(II)-Catalyzed One-Pot β-Arylation of Chromanones with Arylboronic Acids
-
A total of 47 flavanones were expediently synthesized via one-pot β-arylation of chromanones, a class of simple ketones possessing chemically unactivated β sites, with arylboronic acids via tandem palladium(II) catalysis. This reaction provides a novel route to various flavanones, including natural products such as naringenin trimethyl ether, in yields up to 92percent.
- Cho, Yang Yil,Jang, Hyu Jeong,Kim, Dong Hwan,Kim, Nam Yong,Kim, Nam-Jung,Kim, Young Min,Lee, Soo Jin,Lee, Yong Sup,Park, Boyoung Y.,Son, Seung Hwan,Yoo, Hyung-Seok
-
supporting information
p. 10012 - 10023
(2019/08/30)
-
- Catalytic Transfer Hydrogenation Using Biomass as Hydrogen Source
-
We developed an operationally simple method for the direct use of biomass-derived chemical entities in a fundamentally important process, such as hydrogenation. Various carbohydrates, starch, and lignin were used for stereoselective hydrogenation. Employing a transition metal catalyst and a novel catalytic system, the reduction of alkynes, alkenes, and carbonyl groups with high yields was demonstrated. The regioselective hydrogenation to access different stereoisomers was established by simple variations in the reaction conditions. This work is based on an unprecedented catalytic system and represents a straightforward application of biomass as a reducing reagent in chemical reactions.
- Antonchick, Andrey P.,Manna, Srimanta
-
p. 3094 - 3098
(2018/09/14)
-
- Hydrated ferric sulfate-catalyzed reactions of indole with aldehydes, ketones, cyclic ketones, and chromanones: Synthesis of bisindoles and trisindoles
-
Hydrated ferric sulfate [Fe2(SO4)3·xH2O] has been found to be an efficient catalyst for condensation of bisindoles or trisindoles with aliphatic or aryl aldehydes and ketones including methyl and ethyl-alkyl ketones, methyl aryl ketones, cyclic ketones, and 4-chromanones in 19–96% yields. Trisindoles and 2,2'-alkylidenebisindoles were obtained from indole-3-carbaldehydes or 3-methylindole in 72–84% yields. A total of 43 substrates was employed, giving 33 bisindoles, 3 trisindoles, and one 2:2 product; seventeen of these are new. The best results were obtained from heating ethanolic suspensions, with Fe2(SO4)3·xH2O loaded at 60 mg per mmol of electrophiles. The reaction times were typically 1–4 h, while hindered electrophiles required 8–24 h. These conditions were strong enough to promote 2:1 condensation of indole with substrates without forming higher-order byproducts, with few exceptions. This strategy features tolerance by the catalyst of a wide range of functional groups, readily available starting materials, simple operation, mild reaction conditions, and is environmentally friendly.
- Noland, Wayland E.,Kumar, Honnaiah Vijay,Flick, Grant C.,Aspros, Cole L.,Yoon, Jong Hyeon,Wilt, Andre C.,Dehkordi, Nasim,Thao, Sheng,Schneerer, Andrew K.,Gao, Siming,Tritch, Kenneth J.
-
p. 3913 - 3922
(2017/06/13)
-
- Synthesis, characterization, and antimicrobial activity of novel substituted 2H-chromenyl acrylates
-
The present study deals with conventional Witting olefination of 2H-chromene-3-carbaldehydes with stabilized ylide in the presence of dichloromethane to afford (2E)-ethyl-3-(4-chloro-2H-chromen-3-yl) acrylate derivatives. All the products were found to have E-geometry at C=C bond. The synthesized compounds were characterized by spectral data such as IR, 1H NMR and MS. Compounds were screened for antimicrobial activity against strains of gram positive, gram negative bacterial and fungal strains. All compounds showed good antibacterial and antifungal activity.
- Subhashini,Ravi,Cherupally,China Raju,Reddy,Bee
-
p. 2900 - 2905
(2017/03/22)
-
- Rapid synthesis of 4-arylchromenes from ortho-substituted alkynols: A versatile access to restricted iso combretastatin A-4 analogues as antitumor agents
-
Potent anticancer 4-arylchromene agents 6, as restricted isoCA-4 analogues, were prepared with excellent yields by a rapid and versatile synthetic pathway. First, in the presence of PTSA in EtOH, a variety of arylalkynols 9 were transformed into substitut
- Renko, Dolor,Provot, Olivier,Rasolofonjatovo, Evelia,Bignon, Jér?me,Rodrigo, Jordi,Dubois, Jo?lle,Brion, Jean-Daniel,Hamze, Abdallah,Alami, Mouad
-
p. 834 - 844
(2015/03/13)
-
- FeCl3 and ether mediated direct intramolecular acylation of esters and their application in efficient preparation of xanthone and chromone derivatives
-
The direct intramolecular acylation of esters was developed by using the combined system of FeCl3 with Cl2CHOCH3. This unique cooperative system offered a new and efficient approach to biologically important xanthone and chromone derivatives with regioselectivity. Examples were reported, and control experiments were carried out to examine the effect of the benzyl esters and Cl2CHOCH3.
- Jiang, Neng,Li, Su-Yi,Xie, Sai-Sai,Yao, Hequan,Sun, Hongbin,Wang, Xiao-Bing,Kong, Ling-Yi
-
p. 63632 - 63641
(2015/02/19)
-
- A facile solvent free synthesis of 3-arylidenechroman-4-ones using grinding technique
-
An efficient method for the synthesis of 3-arylidenechroman-4-ones has been developed under solvent free conditions using grinding technique. Grinding of variously substituted chroman-4-ones with aromatic aldehydes in presence of anhydrous barium hydroxide at room temperature give 3-arylidenechroman-4-ones in high yield (75-92%). Products are obtained by just acidification of the reaction mixture in ice cold water. Reaction in solid state, with enhanced rate, high selectivity and manipulative simplicity are the attractive features of this environmentally benign protocol. The chroman-4-one derivatives required for the reaction have been obtained by polyphosphoric acid (PPA) catalysed cyclisation of phenoxypropanoic acids under microwave irradiations.
- Kumar, Suresh,Makrandi, Jagdish K.
-
experimental part
p. 1251 - 1256
(2012/05/20)
-
- The enantiospecific synthesis of chromanes and isochromanes using a variant of an intramolecular Nicholas reaction
-
The enantiospecific synthesis of chromanes and isochromanes obtained from an intramolecular Nicholas cyclisation reaction is discussed. During the course of this study we observed the formation of chroman-4-ones from a CAN deprotection step of a dioxolane and this is also discussed.
- Tyrrell, Elizabeth,Mazloumi, Khatebeh,Banti, Donatella,Sajdak, Paulina,Sinclair, Alex,Le Gresley, Adam
-
experimental part
p. 4280 - 4282
(2012/09/22)
-
- Chroman Compound, Processes for Its Preparation, and Its Pharmaceutical Use
-
The present invention provided a chroman compound, the method of its preparation and pharmaceutical applications. The compound are represented by formula (I) and its pharmaceutical salt, where in :x is for O or S; n is for 2, 3 or 4; R1 is 6-situ or 7-situ halogen, C1-4alkyl, C1-4alkyoxyl, benzyloxy, acylamino; R2 is nitrogen-containing pentatomic or hexahydric substituted heterocyclic ring. The compound is useful to prepare anti-arrhythmic drugs, the reaction conditions of the method are mild, the raw material are plenty and easy to be obtained, and the operation and post-treatment are simple.
- -
-
Page/Page column 7
(2008/06/13)
-
- Chemoselective Reduction of α,βUnsaturated Aldehydes, Ketones, Carboxylic Acids, and Esters with Nickel Boride in Methanol-Water
-
A facile procedure for the conjugate reduction of α,β -unsaturated aldehydes, ketones, carboxylic acids, and esters is reported with nickel boride generated in situ from NiCl2·6H 2O/NaBH4 in methanol-water at ambient temperature.
- Khurana, Jitender Mohan,Sharma, Purnima
-
p. 549 - 552
(2007/10/03)
-
- Preparation of 6-substituted 4-chromanones
-
Disclosed is a practical and efficient process for preparing 6-substituted 4-chromanones from phenolic acrylate ester compounds derivable from para-substituted phenolic or thiophenolic compounds and beta-unsubstituted acrylic acid compounds which are esterifiable therewith. The process includes effecting rearrangement of a phenolic or thiophenolic acrylate ester in the presence of a rearrangement effective amount of hydrogen fluoride to the corresponding hydroxy - or mercapto (vinyl ketone) wherein the carbonyl carbon atom of the vinyl carboxy group is directly attached to the benzene ring ortho to the hydroxy or mercapto group. Thereafter, the vinyl ketone is cyclized to the corresponding 6-substituted 4-chromanone in the presence of a cyclization-effective amount of hydrogen fluoride. The 6-substituted 4-chromanones prepared by the process are useful as intermediates for preparing pharmaceutical agents.
- -
-
-
- THERMAL BEHAVIOUR OF ARYL γ-HALOPROPARGYL ETHERS
-
A systematic study of the behaviour of aryl γ-halopropargyl ethers under thermal condition was undertaken.Aryl γ-bromopropargyl ethers 2 underwent unique transformation in N,N-diethylaniline (215 deg C, 6 h) giving rise to a mixture of products 3,4 and 5,whereas, under similar conditions aryl γ-chloropropargyl ethers 8, afforded 4-chlorochromenes, 9.A remarkable substituent and solvent effect has been observed in the thermolysis of these aryl γ-bromo and γ-chloropropargyl ethers, rendering this transformation as a method for the synthesis of a number of substituted 4-bromochromenes 3, 4-chlorochromenes 9 and chroman-4-ones 7.In contrast, solution thermolysis of aryl γ-iodopropargyl ether 11 afforded aryl propargyl ether 1 as the major product.
- Ariamala, G.,Balasubramanian, K. K.
-
p. 309 - 318
(2007/10/02)
-
- A Novel and Convenient Mercury(II) Mediated Synthesis of Chroman-4-ones
-
A simple route to chroman-4-ones from γ-bromopropynyl aryl ethers (1) using mercury(II) trifluoroacetate as a catalyst is described.
- Gopalsamy, Ariamala,Balasubramanian, K. K.
-
-
- A SIMPLE ROUTE FOR THE SYNTHESIS OF 4-CHLOROCHROMENES AND CHROMAN-4-ONES
-
A one pot synthesis of a number of 4-chlorochromenes and chroman-4-ones was achived from γ-chloropropargyl aryl ethers proceeding through Claisen rearrangement, depending upon the solvent of choice.
- Ariamala, G.,Balasubramanian, K.K.
-
p. 3487 - 3488
(2007/10/02)
-
- UNEXPECTED FORMATION OF CHROMAN-4-ONES DURING THE SYNTHESIS OF 4-HYDROXYMETHYL-2H-CHROMENES FROM 4-ARYLOXYBUT-2-YN-1-OLS
-
The unexpected formation of chroman-4-ones by refluxing 4-aryloxybut-2-yn-1-ols in diethylaniline has been studied, 4-hydroxymethyl-2H-chromene and chroman-4-carboxaldehyde derivatives being estbalished as intermediates.
- Camps, P.,Lluch, M.A.,Climent, M.J.,Miranda, M.A.
-
p. 2041 - 2042
(2007/10/02)
-
- A New Class of Antiarrhythmic Agents: Mannich Bases of 3,4-Dihydro-1-benzoxepin-5(2H)-ones and Related Compounds
-
Mannich bases derived from 3,4-dihydro-1-benzoxepin-5(2H)-ones, chromanones and 6,7,8,9-tetrahydrobenzocyclohepten-5(H)-one have been synthesised and shown to possess marked antiarrhythmic activity; 3,4-dihydro-7-methyl-4-(1-piperidinomethyl)- and 3,4-dih
- Khanna, J. M.,Tandon, V. K.,Kar, K.,Sur, R. N.
-
-
