One-pot synthesis of novel pyrido[2,3-d]pyrimidines using HAp-encapsulated-γ-Fe2O3 supported sulfonic acid nanocatalyst under solvent-free conditions

Novel pyrido[2,3-d]pyrimidine derivatives were synthesized through a one-pot three-component approach using HAp-encapsulated-γ-Fe2O3[γ-Fe2O3@HAp-SO3H]catalyzed condensation of 6-arnino-2-（methylthio or ethylthio）pyrimidin-4（3H）-one,Meldrum＇s acid and aryl aldehydes at 60 ℃ and under solvent-free conditions.In this protocol the use of nanocatalyst provided a green,useful and rapid method to generate the products in short reaction times and excellent yields（88%-94%）.     

Highly efficient and green synthesis of 14-aryl(alkyl)-14H-dibenzo[a,j]xanthene and 1,8-dioxooctahydroxanthene derivatives catalyzed by reusable zirconyl triflate [ZrO(OTf)2]under solvent-free conditions

An efficient,convenient and green method has been introduced for the preparation of 14-aryl（alkyl）-14H-dibenzo[a,j]xanthene and 1,8-dioxooctahydroxanthene derivatives by the reaction of aldehydes with 2-naphthol and 5,5-dimethyl-1,3-cyclohexanedione, respectively,in the presence of ZrO（OTf）₂ as a reusable catalyst under solvent-free conditions.In addition,very short reaction times, excellent yields,straightforward procedure,and relatively non-toxicity of the catalyst are other noteworthy advantages of the present method.     

Novel one-pot synthesis of 4H-chromene derivatives using amino functionalized silica gel catalyst

A simple, efficient, and environmentally benign method for the synthesis of 4H-chromene derivatives was developed using well ordered and recoverable amino functionalized silica gel as a base catalyst. The 4H-chromene derivatives were obtained in short time and excellent yield(87%–96%) by three component reaction of aldehydes, malononitrile and cyclic 1,3-diketones in water at 70 8C.     

Zinc oxide nanoparticles:A highly efficient and readily recyclable catalyst for the synthesis of xanthenes

A novel and efficient route for the synthesis of 1,8-dioxooctahydroxanthenes and 14-aryl-14H-dibenzo[a,j]xanthenes is described through one-pot multi-component reaction of dimedone and 2-naphthol with various aryl aldehydes using ZnO nanoparticles under solvent-free conditions.This method provides a novel and improved pathway for the synthesis of xanthenes in the terms of excellent yields,short reaction times,reusability and low catalyst loading.     

Silica supported sodium hydrogen sulfate （NaHSO4/SiO2）： A mild and efficient reusable catalyst for the synthesis of aryl-14-H-dibenzo [aj]xanthenes under solvent-flee conditions

A simple and efficient procedure for the preparation of aryl- 14-H-dibenzo [aj]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes, in the presence of silica supported sodium hydrogen sulfate （NaHSO4/SiO2） as a catalyst and in the absence of solvent has been developed. The present method offers several advantages such as excellent yields, short reaction time （10-30min）, mild condition, simple work-up, and the use of a cheap and environmentally friendly catalyst with remarkable reusability.     

A new facile synthesis of shikalkin

A short and convergent approach for the synthesis of shikalkin （dl-shikonin） is presented. Stobbe reaction was employed to construct the aromatic skeleton 6. This is followed by a practical method to prepare the key epoxides 9 from aldehydes 8 in high yield. Finally, shikalkin is achieved by Grignard reaction and oxidation.     

Ultrasound-assisted one-pot synthesis of 2,4,5-triarylimidazole derivatives catalyzed by ceric (Ⅳ) ammonium nitrate in aqueous media

2,4,5-Triarylimidazoles could be obtained in excellent yields by the one-pot three-component condensation of benzil/benzoin, aldehydes and ammonium acetate in the presence of catalytic amount of the inexpensive,readily available and non-toxic ceric(Ⅳ) ammonium nitrate(CAN) in aqueous media under ultrasound at room temperature.In this reaction the products were obtained in short reaction time and easy operation under mild conditions.     

高效、可重复使用的多相催化剂SiO_2-NaHSO_4用于水中三组分一锅法合成八氢喹唑啉-2,5-二酮(英文)

An environmentally benign method for the synthesis of octahydro-quinazolin-2,5-diones by the reaction of aromatic aldehydes,dimedone,and urea in the presence of SiO2-NaHSO4 is reported.SiO2-NaHSO4 acts as an efficient,mild,and recyclable heterogeneous catalyst to give excellent yields within a short reaction time in water at 60-80℃.     

The convenient synthesis of 4-arylmethylidene-4,5-dihydro-3-phenylisoxazol-5-ones

4-Arylmethylidene-4,5-dihydro-3-phenylisoxazol-5-ones were synthesized by the convenient three-component reaction of ethyl benzoylacetate,hydroxylamine and aromatic aldehydes in the presence of pyridine.The target compounds were also obtained by the reaction between 3-phenylisoxazol-5-one and aromatic aldehydes at 105℃under solvent free condition.Yields of products depended considerably on the aldehyde used.     

Fe（HSO4）3： An efficient,heterogeneous and reusable catalyst for the synthesis of 14-aryl- or alkyl- 14H-dibenzo[a,j]xanthenes

Fe（HSO4）3 has been used as an efficient and recyclable catalyst for the one-pot synthesis of 14-aryl- or alkyl-14Hdibenzo[aj]xanthene derivatives by the reaction of 2-naphtol and aldehydes. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products were obtained in good to excellent yields.     

A General, Highly Efficient Ullmann C-O Coupling Reaction under Microwave Irradiation and the Effects of Water

A general, rapid and highly efficient method for the synthesis of diaryl ethers under the assistance of microwave irradiation was described. A series of diaryl ethers were prepared by direct coupling of phenols and aryl halides in good to excellent yields in anhydrous DMF or NMP at 150 ℃ within 20 rain. The presence of water was found to have a significant impact on the Ullmann C-O coupling reaction between aryl halides and phenols under microwave irradiation.     

以聚(4-乙烯基吡啶)硫酸氢盐为催化剂三组分一锅法合成苯并[f]茚并喹啉(英文)

7‐Aryl‐8H‐benzo[f]indeno[2,1‐b]quinoline‐8‐one derivatives were synthesized by means of a one‐pot condensation of 2‐naphthylamine, aromatic aldehydes, and indane‐1,3‐dione in ethanol under refluxing conditions in the presence of poly(4‐vinylpyridinium) hydrogen sulfate, a solid acid catalyst. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst could be recycled and reused four times without significant loss of activity. The structure of the novel compounds was confirmed by IR, 1H NMR, and 13C NMR spec-troscopy and elemental analysis.     

Nano-sulfated zirconia as an efficient, recyclable and environmentally benign catalyst for one-pot three component synthesis of amidoalkyl naphthols

One pot synthesis of amidoalkyl naphthols by reaction of aromatic aldehydes,2-naphthol and amide/urea using nano-sulfated zirconia as a catalyst is reported.The reaction was carried out under solvent-free conditions.The method gave good yields of amidoalkyl naphthols in short reaction time.The catalyst is recycled for five consecutive times without loss of activity.     

PEG-OSO3H as an efficient and recyclable catalyst for the synthesis of β-amino carbonyl compounds via the Mannich reaction in PEG-H2O

Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO₃H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H₂O（1:1） as environment-friendly solvents.The reactions were completed in short times and mild reaction conditions with good to excellent yields.     

Rapid Synthesis of 1,2,3,4-Tetrahydropyrimidin-2-ones Using Zn（NH2SO3）2 as a Catalyst under Microwave Irradiation

Rapid synthesis of 1,2,3,4-tetrahydropyrimidin-2-ones （THPO） from aromatic aldehydes, β-ketoester and urea （or thiourea） using zinc sulfamate as the catalyst under microwave irradiation was described here. Compared with the classical Biginelli reaction, this new method consistently has the advantages of good yields （76%-96%）, short reaction time （3-15 min）, no corrosion to equipments, ease of manipulation, and low cost catalyst.     

Reduced Species （HSO2^-, SO2^·-） Promoted One-Pot Efficient Synthesis of Phenyl Alkyl Selenides

Reduced species （HSO2^-, SO2^·-） promoted one-pot synthesis of phenyl alkyl selenides has been developed. This synthetic method was achieved by reactions of diphenyl diselenide with alkyl halides at room temperature. It is noteworthy that the reactions were operated under mild reaction conditions, required short time, and got good resuits. A single electron transfer reaction mechanism was proposed for the reaction.     

硅胶硫酸:一种在温和及无溶剂条件下一锅法合成1,4-二氢吡啶的高效多相催化剂(英文)

A series of 1,4-dihydropyridines have been prepared by a one-pot condensation of aldehydes,ethyl acetoacetate,and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at room temperature under solvent-free condition. This new protocol has the advantage of short reaction time and excellent yields,and is an environmentally benign route to the synthesis of 1,4-dihydropyridines.     

A Novel, Simple and Efficient Synthesis of Ferrocenyl Enones and Alkynols

Propargylic alcohols are versatile precursors to many organic molecules including natural products and pharmaceutical compounds.[1] In our continuing interest in the development of practical methods for synthesis of ferrocene derivatives, we decided to investigate the efficiencies of ferrocenylacetylene addition to aromatic aldehydes under t-BuOKcatalyzed condition.[2] Interestingly, we found that the usually reliable coupling reaction between terminal alkyne of type 1 and aromatic aldehydes of type 2 does not furnish the expected propargylic alcohols, but that the isomeric aryl enones 3are found in high yield and very short reaction time (10～20 min). This provided a promising protocol for preparation of ferrocenyl chalcones in a practical, economical and mild sense compared with the traditional method. To the best of our knowledge, this unusual reaction was first observed for the addition of ferrocenylacetylene to aldehyde in a base-catalyzed manner (Eq. 1).     

Propylphosphonic anhydride(T3P~) catalyzed one-pot synthesis of α-aminonitriles

The Strecker reaction was performed via a one-pot three component condensation of hetero aromatic/aromatic aldehydes, secondary amines and trimetylsilyl cyanide in the presence of propylphosphonic anhydride(T3P~) to accomplish the corresponding a-aminonitriles. The main advantages of this method are very short reaction time and excellent yields.     

Boron（Ⅲ） Tribromide or Tianium （Ⅳ） Bromide and Lewis Base Promoted Baylis—Hillman Reaction

It was found that,when the Baylis-Hillman reaction of arylaldehydes with methyl vinyl ketone was carried out at below -20℃ in the presence of boron (Ⅲ） tribromide or titanium (Ⅳ） bromide using a catalytic amount of Lewis base such as amine,the brominated compounds and the Baylis-Hillman adducts could be obtained as the major products in good yields for various aryl aldehydes.But at room temperature,the elimination products were the major products.In addition,the palladium catalyzed allylic substitution reactions of the elimination products were also examined.