共查询到20条相似文献,搜索用时 31 毫秒
1.
Reduction of 2-(polyfluoroalkyl)chromones by sodium borohydride in methanol gives cis-2-(polyfluoroalkyl)chroman-4-ols in high yields, which are easily oxidized by chromic acid to 2-(polyfluoroalkyl)chroman-4-ones.
The latter are of interest as the starting materials for the preparation of novel RF-containing chromane derivatives. 相似文献
2.
An efficient and straightforward approach for the synthesis of carbamoylated chroman-4-ones has been well-developed. The reaction is triggered through the generation of carbamoyl radicals from oxamic acids under metal-free conditions, which subsequently undergoes decarboxylative radical cascade cyclization on 2-(allyloxy)arylaldehydes to afford various amide-containing chroman-4-one scaffolds with high functional group tolerance and a broad substrate scope. 相似文献
3.
(Chromon-3-yl)bis(indol-3-yl)methanes and E-2-hydroxy-3-(1-methylpyrrol-2-ylmethylene)chroman-4-ones have been obtained in good yields from 3-formylchromones on reaction with indoles and N-methylpyrrole under solvent-free conditions. 相似文献
4.
(Chromon-3-yl)bis(indol-3-yl)methanes and E-2-hydroxy-3-(1-methylpyrrol-2-ylmethylene)chroman-4-ones have been obtained in good yields from 3-formylchromones on reaction with indoles and N-methylpyrrole under solvent-free conditions. Reactions of (chromon-3-yl)bis(indol-3-yl)methanes with guanidine carbonate and hydrazine hydrate proceed with the participation of the chromone ring system and lead to the formation of the corresponding pyrimidines and pyrazoles bearing the bis(indol-3-yl)methyl moiety. 相似文献
5.
《中国化学快报》2020,31(12):3255-3258
An efficient method for the synthesis of functionalized chroman-4-ones induced by visible light via the radical cyclization reaction of sulfinic acids and o-(allyloxy)arylaldehydes at room temperature was described. The corresponding products were isolated with moderate to good yields. Radical mechanism was proposed for this transformation. Anti-microbial activity of some desired compounds were screened. 相似文献
6.
I. V. Ukrainets O. V. Gorokhova L. V. Sidorenko 《Chemistry of Heterocyclic Compounds》2005,41(8):1019-1021
The behavior of 2-chloro-4-hydroxy- and 4-chloro-2-oxoquinoline-3-carboxylic acids under acid catalyzed esterification conditions
with methanol has been studied. A method is proposed for obtaining 2-chloro-4-hydroxyquinoline-3-carboxylic acid ethyl ester.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1195–1197, August, 2005. 相似文献
7.
3-Hydroxymethylene derivatives of 2-substituted chroman-4-ones rearrange to 3-alkenylchromones under acid-base conditions. 相似文献
8.
Agisho Habtamu Abebe Hairat Suboot Zaki Mehvash 《Monatshefte für Chemie / Chemical Monthly》2020,151(4):599-603
Monatshefte für Chemie - Chemical Monthly - A transition metal-free and efficient TBHP/TBAI-mediated protocol has been developed for the synthesis of 4H-chromen-4-ones from chroman-4-ones via... 相似文献
9.
Herein, we describe the synthesis of a variety of chiral hybrid pyrrolidine-chromanone polycyclic derivatives. A convenient (3+2)-annulation of azomethine ylides with chromone-3-carboxylic acid realized under Brønsted base catalysis produced highly functionalized products in high yields with good stereoselectivities through asymmetric, intermolecular, and decarboxylative (3+2)-cyclization. 相似文献
10.
An efficient and practical decarboxylative cross-coupling reaction of quinolin-4(1H)-one 3-carboxylic acids with (hetero)aryl halides has been established. Under a bimetallic system of PdBr(2) and silver carbonate, the protocol proved to be general, and a variety of 3-(hetero)aryl 4-quinolinones and related heterocycles, such as 3-aryl-1,8-naphthyridin-4(1H)-ones, 3-arylcoumarins, 3-arylquinolin-2(1H)-ones, and 2-arylchromones, can be prepared in good to excellent yields. 相似文献
11.
A facile photochemical preparation of 5-, 6-, and 7-substituted chroman-4-ones from aryl 3-methyl-2-butenoate esters is described. The two-phase base-catalyzed method relies upon two consecutive processes in one-pot reaction through a photo-Fries rearrangement and a based-catalyzed intramolecular oxa-Michael addition to afford the desired products. 相似文献
12.
Guang-Hui Li Qing-Qing Han Yuan-Yuan Sun De-Mao Chen Zu-Li Wang Xin-Ming Xu Xian-Yong Yu 《中国化学快报》2021,31(12):3255-3258
An efficient method for the synthesis of functionalized chroman-4-ones induced by visible light via the radical cyclization reaction of sulfinic acids and o-(allyloxy)arylaldehydes at room temperature was described. The corresponding products were isolated with moderate to good yields. Radical mechanism was proposed for this transformation. Anti-microbial activity of some desired compounds were screened. 相似文献
13.
Denis R. St. Laurent 《Tetrahedron letters》2004,45(9):1907-1910
Cyclization of unsymmetrical thioureas affords 3-(heteroaryl)-iminothiazolidin-4-ones with excellent levels of regiocontrol. In the absence of base, 2-(pyridylmethyl) and 2-(aminomethyl)benzimidazolyl substituents on the thiourea scavenge acid that is generated upon sulfur alkylation with bromoesters. The resulting conjugate acid plays an important role in influencing the regiochemical outcome and overall rate of the reaction. 相似文献
14.
Kevin J. Hodgetts 《Tetrahedron》2005,61(28):6860-6870
Two approaches to optically active 2-substituted chromans and chroman-4-ones are described. The first utilized an intermolecular Mitsunobu reaction of a homochiral halopropanol and 2-bromophenol followed by cyclization to the 2-substituted chroman. In addition, a double lithiation procedure was developed to introduce additional functionality to the chroman. The second approach utilized an intramolecular Mitsunobu cyclization to give the 2-substituted chroman-4-one nucleus. The methodologies were applied to the syntheses of several biologically active natural and synthetic products. 相似文献
15.
16.
Boris I. Usachev Sergey A. UsachevGerd-Volker Röschenthaler Vyacheslav Ya. Sosnovskikh 《Tetrahedron letters》2011,52(50):6723-6725
4-Aryl-6-(trifluoromethyl)-2H-pyran-2-ones and ethyl 4-aryl-6-(trifluoromethyl)-2-oxo-2H-pyran-3-carboxylates react with sodium azide to produce highly functionalized CF3-1,2,3-triazoles: 3-[5-(trifluoromethyl)-1,2,3-triazol-4-yl]cinnamic acids and monoethyl esters of [5-(trifluoromethyl)-1,2,3-triazol-4-yl]arylmethylidene malonic acids. 相似文献
17.
Pranab Haldar 《Tetrahedron letters》2008,49(22):3659-3662
An efficient and mild protocol for one-pot decarboxylative hydroxylation/alkoxylation of 1,3-diaryl-5-oxo-pyrrolidine-2-carboxylic acids to trans-5-hydroxy-1,4-diarylpyrrolidin-2-ones and 5-alkoxy-1,4-diaryl-1,5-dihydropyrrol-2-ones at room temperature using CAN in organo-aqueous solvent has been developed. 相似文献
18.
3-(2-氧代环烷基)丙酸与(R)-2-硫代四氢噻唑-4-羧酸乙酯的反应李叶芝,田颜清,黄化民(吉林大学化学,长春,130023)关键词(R)-2-硫代四氢噻唑-4-羧酸乙酯,N-3-(2-氧代环烷基)丙酰-2-硫代四氢噻唑-4-羧酸乙酯,环合反应,... 相似文献
19.
20.
Sirisilla Raju Venkateswara Rao Batchu R. Vasu Dev P. Rajender Kumar Manojit Pal 《Tetrahedron letters》2006,47(1):83-88
We describe here, the first palladium-mediated tandem C-C bond forming reaction between 3-iodothiophene-2-carboxylic acid and terminal alkynes to afford the unexpected 5-substituted 4-alkynylthieno[2,3-c]pyran-7-ones in good yields. 相似文献