A powerful, practical and chemoselective synthesis of 2-anilinoalkanols catalyzed by Bi(TFA)3 or Bi(OTf)3 in the presence of molten TBAB

Development of a novel carboxamide-based off–on switch fluorescence sensor: Hg2+, Zn2+ and Cd2+

Here, the carboxamide ligand N-(thiazole-2-yl) picolinamide (L) was synthesized in an ionic liquid tetrabutylammonium bromide (TBAB) as the benign reaction medium.

Recent developments on ultrasound assisted catalyst-free organic synthesis

Mother Nature needs to be protected from ever increasing chemical pollutions associated with synthetic organic processes. The fundamental challenge for today's methodologists is to make their protocols more environmentally benign and sustainable by avoiding the extensive use of hazardous reagents and solvents, harsh reaction conditions, and toxic metal catalysts. However, the people of the twenty-first century are well aware about the side effects of those hazardous substances used and generated by the chemical processes. As a result, the last decade has seen a tremendous outburst in modifying chemical processes to make them 'sustainable' for the betterment of our environment. Catalysts play a crucial role in organic synthesis and thus they find huge applications and uses. Scientists' continuously trying to modify the catalysts to reduce their toxicity level, but the most benign way is to design an organic reaction without catalyst(s), if possible. It is worthy to mention that the involvement of ultrasound in organic synthesis is sometimes fulfilling this goal. In many occasions the applications of ultrasound can avoid the use of catalysts in organic reactions. Such beneficial features as a whole have motivated the organic chemists to apply ultrasonic irradiation in more heights and as a results, in recent past, there were immense applications of ultrasound in organic reactions for the synthesis of diverse organic scaffolds under catalyst-free condition. The present review summarizes the latest developments on ultrasound assisted catalyst-free organic synthesis reported so far.

Applications of bismuth(III) compounds in organic synthesis

This review article summarizes the applications of bismuth(III) compounds in organic synthesis since 2002. Although there are an increasing number of reports on applications of bismuth(III) salts in polymerization reactions, and their importance is acknowledged, they are not included in this review. This review is largely organized by the reaction type although some reactions can clearly be placed in multiple sections. While every effort has been made to include all relevant reports in this field, any omission is inadvertent and we apologize in advance for the same (358 references).

Ultrasound promoted aminolysis of epoxides in aqueous media: a rapid procedure with no pH adjustment for additive-free synthesis of beta-aminoalcohols

An efficient and environmentally friendly procedure promoted by ultrasound irradiation is developed for stereoselective ring opening of various epoxides with aromatic and aliphatic amines under aqueous conditions in the presence of no catalyst or additive. Chemoselectivity of the protocol is shown by competition of piperidine and aniline to react with different epoxides resulting in exclusive formation of the respective products of piperidine.

Green Methodology with Ionic Liquids as a Media for Efficient Synthesis of Polyamides Derived from 4-(4-Dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione and Diacid Chlorides2

Ionic liquids (ILs) represent a fascinating and potentially very valuable group of new solvents, which have the benefit of zero vapor pressure and therefore easier handling than many conventional solvents. They are attracting a lot of attention as volatile organic compound-free solvents, eco-friendly and green media. Room-temperature ionic liquids (RTILs) and particularly those based on substituted imidazolium cations, which can be synthesized easily from the commercially available starting material N-trimethylsilylimidazole and alkyl halides, are currently being extensively studied for a variety of applications. In this study a facile and efficient synthesis of heterocyclic polyamides by polycondensation of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione with various commercially available aliphatic diacid chlorides in the presence of RTILs and molten tetrabutylammonium bromide as an IL was performed. The effect of various reaction parameters, including the nature of the ILs, the amount of IL, the reaction temperature, and the reaction time were investigated to optimize the conditions for the preparation of heterocyclic polyamides. The polymerization proceeded well in ILs without any catalyst and polyamides were obtained with high yields and moderate inherent viscosities. A comparative study between the effects exerted by different ILs and the conventional polymerization method is also reported.

Zinc(II) perchlorate hexahydrate catalyzed opening of epoxide ring by amines: applications to synthesis of (RS)/(R)-propranolols and (RS)/(R)/(S)-naftopidils

Commercially available zinc(II) perchlorate hexahydrate [Zn(ClO4)2.6H2O] was found to be a new and highly efficient catalyst for opening of epoxide rings by amines affording 2-amino alcohols in high yields under solvent-free conditions and with excellent chemo-, regio-, and stereoselectivities. For unsymmetrical epoxides, the regioselectivity was influenced by the electronic and steric factors associated with the epoxides and the amines. A complementarity in the regioselectivity was observed during the reaction of styrene oxide with aromatic and aliphatic amines: aromatic amines provided amino alcohols from nucleophilic attack at the benzylic carbon as major products whereas aliphatic amines resulted in formation of the amino alcohols through reaction at the terminal carbon atom of the epoxide ring as the major/sole products. Reaction of aniline with various glycidic ethers gave the amino alcohols by regioselective nucleophilic attack at the terminal carbon atom of the epoxide ring as the only/major product. Zinc(II) perchlorate hexahydrate was found to be the best catalyst compared to other metal perchlorates. The counteranion modulated the catalytic property of the various Zn(II) compounds that followed the order Zn(ClO4)2.(6)H2O>>Zn(BF4)2 approximately Zn(OTf)2>>ZnI2>ZnBr2>ZnCl2>Zn(OAc)2>Zn(CO3)2 in parallelism with the acidic strength of the corresponding protic acids (except for TfOH). The applicability of the methodology was demonstrated by the synthesis of cardiovascular drugs propranolol and naftopidil as racemates and optically active enantiomers.

A novel enamination of β-dicarbonyl compounds catalyzed by Bi(TFA)3 immobilized on molten TBAB

Enamination of a wide variety of primary amines was successfully carried out in the presence of catalytic amounts of bismuth(III) trifluoroacetate immobilized on molten tetrabutylammonium bromide as "green" media under mild conditions. This new system of the catalyst is recyclable and reusable. Generally, the results of the reaction in tetrabutylammonium bromide is better than the previously obtained results in water because of their yields and reaction times.Key words: amine, bismuth compounds, β-dicarbonyl compounds, enamination, ionic liquid.