A generalised route for the synthesis of β-furyl-α,β-unsaturated aldehydes through Suzuki reactions

A general method for the synthesis of β-(2-furyl)-α,β-unsaturated aldehydes is described using the Suzuki coupling reaction of furan-2-boronic acids and β-bromo-α,β-unsaturated aldehyde derivatives.     

Pd/C-Catalyzed coupling and cyclization of β-bromo-α,β-unsaturated carboxylic acids with terminal alkynes leading to alkylidenefuranones

Palladium-catalyzed coupling of β-bromo-α,β-unsaturated carboxylic acids with terminal alkynes and subsequent regioselective 5-exo-dig cyclization produces (Z)-alkylidenefuranones in good yields.     

Microwave-promoted one-pot synthesis of 4H-thiopyrans from α,β-unsaturated ketones via a three-component reaction

An efficient one-pot synthesis of substituted 4H-thiopyrans has been accomplished from a three-component reaction of α,β-unsaturated ketones, Lawesson’s reagent and alkynes under microwave irradiation.     

Microwave-assisted efficient, one-pot, three-component synthesis of 3,5-disubstituted 1,2,4-oxadiazoles under solvent-free conditions

A novel synthesis of 1,2,4-oxadiazoles is described from a one-pot, three-component reaction between nitriles, hydroxylamine, and aldehydes under microwave irradiation and solvent-free conditions in excellent yields.     

An efficient room temperature preparation of bromo difluorovinylzinc reagent (CF2CBrZnCl) and a high yield one-pot synthesis of α-bromo-β,β-difluorostyrenes

A high yield room temperature preparation of the1-bromo-2,2-difluorovinylzinc reagent [CF₂CBrZnCl] (>89%) was achieved via insitu metallation of CF₃CH₂Br or CF₂CHBr with LDA in presence of ZnCl₂. Palladium catalyzed cross-coupling of this zinc reagent with aryl iodides provides α-bromo-β,β-trifluorostyrenes (ArCBrCF₂) in 64-86% isolated yields, in an essentially ‘one-pot’ procedure.     

Diastereoselective approach to novel octahydroisoquinolones and an extension to its one-pot synthesis

The present Letter describes the use of β-lactams for the synthesis of functionalized β-amino esters and their transformation to trisubstituted octahydroisoquinolone derivatives in good yields with an extension to their one-pot synthesis.     

The general approach for the synthesis of substituted cyclobutenyl- and norbornadienyllithiums containing masked trifluoromethyl group

α,β-Unsaturated trifluoromethylketones of cyclobutene number containing trimethylstannyl substituent in β-position were firstly prepared by the addition of trimethylstannyllithium to the corresponding trifluoromethylenaminoketones. The protection of carbonyl function under basic conditions conserving the organometallic substituent was elaborated. The generation of corresponding organolithiums by Sn-Li exchange and their reactivity was studied.     

A facile synthesis of steroidal D-ring fused pyrazolo[1,5-a]pyrimidines

A facile method for the synthesis of steroidal D-ring fused pyrazolo[1,5-a]pyrimidines through a microwave mediated reaction between steroidal β-bromovinyl aldehydes and pyrazoloamines using palladium(II) catalyst has been described.     

Microwave-assisted fast and efficient synthesis of some crown ethers

13-Crown-4,16-crown-5,dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields.Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect.     

Recent developments in the metal catalysed cross-coupling reactions for the synthesis of the enone system of chalcones

For the last two decades, chalcones and their derivatives have attracted special interest among researchers due to their pharmaceutical properties. Numerous research works have been still going on to improve the methodologies of chalcone synthesis. Chalcone has displayed a remarkable curative efficiency to cure numerous diseases and it continues to show promise for new drug investigations. This review highlights the metal catalysed cross-coupling reactions for the synthesis of chalcone and its derivatives from 2009 to 2020.     

One pot synthesis of unsymmetrical dihydropyridines by green,catalyst free and environmentally benign protocol

Abstract

A facile and ecofriendly synthesis of β-enamino esters is reported by reaction of both aliphatic and aromatic amines with β-keto esters by refluxing in ethanol in absence of any catalyst. Addition of α,β-unsaturated aldehydes to the reaction mixture leads to the formation of unsymmetrical dihydropyridine derivatives which generally are metal free hydrogen sources for asymmetric reduction reactions.     

Microwave-assisted synthesis utilizing supported reagents: a rapid and versatile synthesis of 1,5-diarylpyrazoles

The application of microwave heating to a silica-assisted solution-phase synthesis technique has been utilized to develop a rapid and efficient two-step protocol for the preparation of pyrazoles from aryl methyl ketone and aryl hydrazine monomers.     

An efficient method for the synthesis of gem-difluoroolefins

A series of gem-difluoroolefin derivatives were synthesized in moderate to good yields by the reaction of α,α-difluoro-β-carbonyl benzothiazol-2-yl sulfones (DFBTs) with various carbon nucleophiles. Using dl-proline as organocatalyst, the reaction of DFBT with acetone gave a tertiary alcohol, which could be further converted to the corresponding difluoroolefin by LDA.     

Microreactors for the synthesis of fluorinated materials

The utility of microreactor for the synthesis of α-fluoro-α,β-unsaturated esters, trifluoromethylation and Michael addition reaction, is described.     

Microwave-assisted synthesis of fused heterocycles incorporating trifluoromethyl moiety

4,4,4-Trifluoro-1-(thien-2-yl)butane-1,3-dione (1) reacts with 5-aminopyrazole, 1,2,4-aminotriazole and 2-aminobenzimidazole derivatives, in the presence of triethylorthoformate under pressurized microwave irradiation to afford the corresponding trifluoromethyl derivatives of pyrazolo[1,5-a]pyrimidine, 1,2,4-triazolo[1,5-a]pyrimidine, and pyrimido[1,2-a]benzimidazoles. Also, compound 1 couples readily with azole diazonium salts to give pyrazolo[5,1-c]triazine, benzimidazo[5,1-c]1,2,4-triazine, and triazolo[3,4-c]1,2,4-triazine derivatives incorporating trifluoromethyl group.     

Copper-mediated synthesis of α-trifluoromethylthio- and seleno-α,β-unsaturated carbonyl compounds

A novel route to the synthesis of α-trifluoromethylthio- and seleno-α,β-unsaturated carbonyl compounds via a copper-mediated trifluoromethylthiolation/trifluoromethylselenolation of α-halo-α,β-unsaturated carbonyl substrates is reported.     

InBr3-catalyzed stereoselective synthesis of trans-2,6-disubstituted 3,6-dihydro-2H-pyrans

A new method for the stereoselective synthesis of trans-2,6-disubstituted 3,6-dihydro-2H-pyrans with a variety of substitution patterns is described, involving Lewis acid induced tandem allylation or cyanation of δ-hydroxy-α,β-unsaturated aldehydes to produce dihydropyrans in good yields and with trans-selectivity. This method is very useful for the synthesis of trans-2,6-disubstituted dihydropyran ring-containing natural products such as laulimalide, scytophycin C and many others.     

Microwave-assisted selective and efficient synthesis of 1,3,5-triazinyl mono and bisureas

An efficient and sustainable microwave-assisted approach for the one-step preparation of a wide range of 1,3,5-triazinyl mono- and bisureas has been developed, combining solvent-free conditions and microwave irradiation. In these conditions the very unreactive amino groups of 1,3,5-triazine-2,4-diamines successfully react with phenylisocyanate to yield selectively mono and bisureas.     

Efficient one-pot synthesis of anti-HIV and anti-tumour β-carbolines

Thermal electrocyclisation of the azahexatriene system has been used as a key step for the synthesis of anti-HIV and anti-tumour compounds, harman, derivatives of harman and 1-aryl-β-carbolines. A one-pot reaction sequence was used to furnish these compounds in good yield.     

左氧氟沙星3-芳苄叉基-喹啉-4-酮衍生物的合成及抗肿瘤活性

为进一步发现提高氟喹诺酮抗肿瘤活性的有效结构修饰策略,基于片段药物设计原理,通过喹啉-4(1H)-酮与芳香醛缩合反应合成了(S)-6-氟-7-(4-甲基-哌嗪-基)-8,1-(1,3-氧丙基)-3-芳苄叉基-2,3-二氢-喹啉-4(1H)-酮(3a-3l)目标化合物。 体外抗肿瘤活性结果表明,所合成的12个新化合物的活性均强于母体左氧氟沙星,其中F、Cl、Br取代的卤苯基化合物对人肝癌细胞株(SMMC-7721)和人胰腺癌细胞株(Capan-1)的半数抑制浓度(IC₅₀)低于其它取代基化合物,尤其是氯苯基化合物(3k)与对照抗肿瘤药阿霉素活性相当。 为此,芳苄叉基替代C-3羧基构建的3-芳苄叉基-喹啉-4-酮化合物有助于提高氟喹诺酮的抗肿瘤活性,提示α,β-不饱和酮片段作为一个有发展前景的氟喹诺酮的候选修饰基团值得进一步发展。