An efficient synthesis of β-ketoesters via transesterification and its application in Biginelli reaction under solvent-free,catalyst-free conditions

A simple and efficient transesterification process for the synthesis of β-ketoester derivatives has been achieved by the reaction of methyl β-ketoester with higher alcohols at 110 °C under solvent-free, catalyst-free conditions and its application in synthesis of 3,4-dihydropyrimidin-2(1H)-ones C-5 ester derivatives via Biginelli reaction has been described.     

A regio- and stereoselective three-component synthesis of 5-(trifluoromethyl)-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidine derivatives under solvent-free conditions

An efficient one-pot method for regio- and stereoselective synthesis of 5-(trifluoromethyl)-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidines under solvent-free and catalyst-free conditions has been developed. The method involves employing a three-component condensation reaction of an aromatic aldehyde and ethyl 4,4,4-trifluoro-3-oxobutanoate or 1,1,1-trifluoropentane-2,4-dione in the presence of 1,2,4-triazol-3-amine at 90°C.     

A catalyst- and solvent-free selective approach to biologically important quinazolines and benzo[g]quinazoline

A solvent-free and catalyst-free approach towards the selective synthesis of quinazolines and benzo[g] quinazolines has been developed using conventional microwave oven with excellent yields and reproducibilty.     

Visible light irradiation promoted catalyst-free and solvent-free synthesis of pyrano[2,3-d]pyrimidine scaffolds at room temperature

A catalyst-free and solvent-free synthetic route for convenient one-pot synthesizing pyrano[2,3-d] pyrimidine scaffolds through Knoevenagel-Michael cyclocondensation is reported using visible light irradiation as a green promoter at room temperature based on green chemistry principles. Completing the reactions takes thoroughly less time while obtaining the products in outstanding yields. This green method includes the application of non-hazardous reaction circumstances, direct work-up without column chromatographic separation, catalyst-free, solvent-free, cost effective, simple synthesis, one-pot procedure, and high atom-economy.     

Solvent-free and transition metal catalyst-free synthesis of indolo[1,2-f]phenanthridine from 6-chlorophenanthridine

A new easily scalable synthesis of the important for materials chemistry indolo[1,2-f]phenanthridine from commercially available 6-chlorophenanthridine was developed. The suggested transition metal catalyst-free and solvent-free procedure is more ecologically friendly and cost efficient then the known methods. The yields of indolo[1,2-f]phenanthridine synthesized from 6-chlorophenanthridine in three steps were 20% and 26% if the cyclization was carried out solvent-free and in THF in the presence of lithium 2,2,6,6-tetramethylpiperidide, respectively.

     

An efficient synthesis of 3-benzylquinazolin-4(1H)-one derivatives under catalyst-free and solvent-free conditions

Abstract

An efficient and convenient method for the preparation of 3-benzylquinazolin-4(1H)-one derivatives under solvent-free and catalyst-free conditions by the reaction of isatoic anhydride, benzylamine, and aromatic aldehydes was reported. In reported papers, ammonia water, ammonium salt, and aromatic amine were often used to synthesize quinazolin-4(1H)-one derivative, but benzylamine was seldom used in this synthesis. This article offers a green method for the synthesis of 3-benzylquinazolin-4(1H)-one derivative used benzylamine as starting material. This methodology has the advantages of short reaction time, mild reaction conditions, easy work-up, and environmental friendliness.     

A simple approach to benzothiazoles from 2-chloronitrobenzene,elemental sulfur,and aliphatic amine under solvent-free and catalyst-free conditions

A novel solvent-free and catalyst-free synthesis of benzothiazoles from 2-chloronitrobenzene, elemental sulfur, and aliphatic amine has been developed. The reaction tolerated a wide range of functionalities, and various benzothiazoles were synthesized in moderate to good yields in the absence of external oxidant or reductant.     

Catalyst- and solvent-free mechanochemical synthesis of isoxazoles from N-hydroxybenzimidoyl chlorides and enamino carbonyl compounds

A regioselective, solvent-free and catalyst-free synthesis of isoxazoles has been successfully developed under ball milling conditions. Milling the mixtures of N-hydroxybenzimidoyl chlorides and enamino carbonyl compounds in a ball mill at a frequency of 14.6?Hz for 20–60?min afforded isoxazoles in up to 86% yields. A possible reaction mechanism leading to the formation of the observed isoxazoles is proposed.     

Microwave-assisted solvent-free and catalyst-free Kabachnik-Fields reactions for α-amino phosphonates

A highly efficient solvent-free and catalyst-free method for the synthesis of α-amino phosphonates is developed by a microwave-assisted three-component Kabachnik-Fields reaction involving aldehyde, amine, and dimethyl phosphite.     

Catalyst and solvent-free, ultrasound promoted rapid protocol for the one-pot synthesis of α-aminophosphonates at room temperature

An ultrasound promoted easy, efficient, and environment friendly process has been devised for the synthesis of α-aminophosphonates within seconds through a one-pot three-component condensation of the aldehydes, amines, and triethylphosphite. The desired products were obtained in excellent yields and in high purity under solvent-free and catalyst-free conditions. Study with various aldehydes and amines reveals that ultrasound radiation plays a key role in the direct synthesis of α-aminophosphonates.     

Direct Synthesis of Allylic Thioethers Under Greener Conditions: A Solvent- and Catalyst-Free Approach

We present herein a new catalyst-free and solvent-free approach for the synthesis of allylic thioethers directly from allylic alcohols and thiols. The methodology allows the synthesis of different allylic thioethers in good to excellent yields under microwave irradiation. Theoretical calculations for the allylic carbocation helped to explain the regioselectivity observed when nonsymmetric substrates are used in the reaction.     

Facile,catalyst-free,microwave-assisted access toward the synthesis of 2-aryl/alkyl-3-(1H-benzo[d]imidazol-2-yl)-2, 3-dihydroquinazolin-4(1H)-ones

An efficient, catalyst-free, microwave-assisted approach has been developed for the synthesis of 2-aryl/alkyl-3-(1H-benzo[d]imidazol-2-yl)-2,3-dihydroquinazolin-4(1H)-one derivatives by condensing 2-aminobenzamides with various aliphatic, aromatic, and heterocyclic aldehydes. This catalyst-free approach exhibited good functional group compatibility and produced the desired products in good to excellent yields in just 10–20?min. This approach can be seen as a better alternative of the metal-catalyzed protocols used for the synthesis of this class of compounds. The formation of desired compound has also been confirmed by X-ray analysis.     

芳基咪唑并[4,5-f][1,10]菲咯啉的无溶剂绿色合成研究

以菲咯啉二酮、苯甲醛及其衍生物和醋酸铵为原料,采用无溶剂绿色研磨工艺,合成了芳基咪唑并菲咯啉化合物.通过对不同反应条件的筛选,得到一条高效、简便、绿色的合成芳基咪唑并菲咯啉化合物路线,不同的芳醛与菲咯啉二酮都可以较高的收率得到相应的芳基咪唑并[4,5-f][1,10]菲咯啉.     

Facile Method for One-Step Synthesis of 2,4,5-Triarylimidazoles Under Catalyst-Free,Solvent-Free,and Microwave-Irradiation Conditions

A green and efficient method for the synthesis of 2,4,5-triarylimidazoles by one-step condensation reaction of benzil, aromatic aldehyde, and ammonium acetate under catalyst-free, solvent-free, and microwave-irradiation conditions is reported. This method had many dramatic advantages, such as the short reaction time (3–5 min), good yields (80–99%), environmental friendliness, and convenient operation.     

Simple and Efficient Procedure for the Synthesis of Symmetrical Bis-Schiff Bases of 5,5′-Methylenebis(2-aminothiazole) Under Solvent-Free Conditions

A simple and efficient procedure for the synthesis of symmetrical bis-Schiff bases has been described that employs a condensation reaction of symmetrical primary bis-amine of 5,5′-methylenebis(2-aminothiazole) with a series of aromatic aldehyde derivatives under solvent-free conditions at elevated temperature. The advantages of these reactions are simplicity of the reaction procedure, short reaction times, simple workup, catalyst-free conditions, and pure products in good to excellent yields. Details of the reaction conditions are discussed.     

Catalyst-free and solvent-free method for the synthesis of quinoxalines under microwave irradiation

A facile procedure for the synthesis.of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. Thereactions were carried out catalyst-free, solvent-free and under microwave irradiation conditions in high yield (84-98%) with short time (3-6 rain) and environmental benign, as well as convenient operation. The structures of all the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, mass spectral data.     

Microwave-Assisted Catalyst-Free and Solvent-Free Method for the Synthesis of Quinoxalines

A green and efficient procedure for the synthesis of quinoxalines is reported starting from benzil and 1,2-diaminobenzene. The reactions were carried out under catalyst-free, solvent-free, and microwave-irradiation conditions, affording the corresponding quinoxalines. This method had many dramatic advantages, such as the short reaction time (2–6 min), high yields (71–98%), and environmental friendliness, as well as convenient operation.     

A mild and novel synthesis of functionalized fused imidazole analogues under environmentally benign reaction media

A mild and novel approach is described for the synthesis of functionalized fused imidazole analogues in solvent-free and catalyst-free condition in ionic liquid. The short reaction time, good isolated yields, generality and environmentally benign reaction media are the significant features of this protocol.     

无溶剂无催化条件下一锅合成芳酰基腈化合物

无溶剂无催化剂条件下,以芳香酸、二氯亚砜和铁氰化钾为原料,经氯化、氰化两步一锅合成了一系列芳酰基腈化合物。 考察了氰化过程中反应温度、反应时间对产率的影响。 实验结果表明,其最佳反应条件为：反应温度为180 ℃,反应时间为2 h,产物收率达71%~92%。 产物经IR、1H NMR和13C NMR分析确认。 本方法具有工艺操作简单、产率高、无溶剂无催化和环境友好等优点。     

Dual role of ammonium acetate for solvent-free synthesis of 1,3-disubstituted-2,3-dihydro-1H-naphth-[1,2e] [1,3]-oxazine

Abstract

Ammonium acetate plays a dual role for the solvent-free synthesis of 1,3-oxazine under neat heating at 60°C and under microwave irradiation with excellent yields. The synthetic strategy involved the formation of a Betti base which upon condensation with aromatic aldehydes gives the preferred oxazine ring. The present protocol contributes remarkable advantages, such as solvent- and catalyst-free reaction conditions, simple work-up procedures, shorter reaction times, and environmentally benign methodology.