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Green protocols for the syntheses of 3,3′-arylidenebis-4-hydroxycoumarins and dimethyl ((substituted phenyl) (phenylamino)methyl) phosphonates have been first time developed using biocatalyst, CAL-B (lipase). These are carried at room temperature under stirring and are convenient and cost effective. The developed protocols are environmentally acceptable and are giving better to excellent yields of the titled products.

In the present work, bakers yeast catalyzed efficient synthesis of 2-amino-2-chromenes in methanol is presented. Here the ultrasonication has dual role i.e. as a source of energy for the reaction and tool for the disruption of the yeast cells. The cyclocondensation has been essentially carried under neutral conditions, thus reducing the possibility of unwanted side reactions.

Water mediated and baker’s yeast catalyzed, efficient synthetic routes have been first time developed for multicomponent cyclocondensations leading to bioactive tetrahydrobenzo[a]xanthene-11-ones (4a–h) and pyrazolo[3,4-b]quinolines (7a–i). The developed protocols are conducted at room temperature and gave better to excellent yields of the titled compounds. The biocatalytical resource, activated baker’s yeast is readily available, and biodegradable. These protocols are more convenient, scalable, and obey most of the green principles also. The developed protocols are cost effective and better in operation than existing ones.

A series of new 2-(4-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)benzo[d]thiazoles and 2-(4-((4-(benzo[d]thiazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazol-1-yl)-N-phenylacetamides (5a–t) have been synthesized via a copper fluorapatite (CuFAP) catalysed click reaction. The compounds (5a–t) were synthesized using freshly prepared 2-aryl-4-hydroxybenzothiazole (1) as a starting material. 2-Aryl-4-hydroxybenzothiazole (1) was condensed with propargyl bromide (2) in N,N-dimethylformamide in the presence of potassium carbonate to obtain a key intermediate, benzothiazolyl phenoxymethylalkyne (3). This alkyne (3) was then separately subjected to subsequent click chemistry with freshly prepared aryl/benzyl azides and substituted 2-azido-N-phenylacetamides (4a–t) in the presence of copper fluorapatite (CuFAP) and triethyl amine and good to excellent yields of the title compounds (5a–t) were obtained. All the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and HRMS analyses. All the synthesized compounds were found to be effective against human breast carcinoma (MCF-7) cells. Among them, compounds 5e, 5h, 5j, 5o and 5p were found to be strong inhibitors for the growth of MCF-7 cells with IC50 values of 10.14, 9.84, 10.06, 10.13 and 9.19 μg mL−1, respectively. In addition, compounds 5a, 5c, 5d, 5e, 5f, 5k, 5n, 5o and 5q have shown activity against a multidrug resistant pathogenic strain of E. coli with MIC values of 7.99, 8.44, 8.11, 8.06, 8.54, 9.40, 8.02, 9.25 and 10.62 μg mL−1, respectively.

An efficient and simple one-pot protocol has been developed for synthesis of substituted derivatives of 2-hydrazono-4-thiazolidinone-5-acetic acids 4a–j and 6a–g by cyclocondensation of aryl/pyrazolyl aldehyde, thiosemicarbazide and maleic anhydride in acetonitrile in the presence of readily available whole cell biocatalyst, baker’s yeast (Saccharomyces cerevisiae). The reaction is enhanced by ultrasonication.

A convenient synthesis of 6-amino-2 H ,4 H -pyrano[2,3- с ]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes ( 1a-o ) malanonitrile ( 2 ), ethyl acetoacetate ( 3 ), and hydrazine hydrate ( 4 ) in freshly prepared deep eutectic solvent, DES (choline chloride:urea). This protocol has afforded corresponding pyrano[2,3- с ]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.

Novel one-pot synthetic protocol has been developed for obtaining 2, 3-disubstituted 1,4-benzothiazines with excellent yields, carrying cyclocondensation of 1,3-dicarbonyl compounds with substituted 2-(2-(2-aminophenyl)disulfanyl)benzenamines, under supramolecular catalysis of β-Cyclodextrin (β-CD) in water at neutral pH. The role of β-CD in accelerating the cyclocondensation has been demonstrated. This biomimic catalyzed route is simple, economic, relatively rapid and environmentally benign.

A convenient one-pot, rapid and scalable synthetic protocol has been developed for recently reported anti-inflammatory agents, thiazole-substituted pyrazolyl-4-thiazolidinones. Quantitative multicomponent cyclocondensation of 3-(4-methyl-2-substituted thiazol-5-yl)-1-phenyl-1H-pyrazole-4-carbaldehydes (5a, b), amines and mercaptoacetic acid has been carried out in safer medium, diisopropylethylammonium acetate, at room temperature. The optimisation details of the developed novel protocol are recorded.

A simple and efficient protocol developed for the synthesis of 5-substituted 1H-tetrazole derivatives through [2+3] cycloaddition reaction between benzonitriles and sodium azide using diisopropylethylammonium acetate as a recyclable reaction medium is described. The reactions proceed well at 80 °C and provide the corresponding tetrazoles in good to excellent yields (up to 94% yield). Developed method has notable advantages, such as simple and mild conditions, easy workup, reusability with consistent catalytic activity, and safer alternative to hazardous, corrosive conventional Lewis acid catalysts.

An efficient synthesis of 5-arylidine-2,4-thiazolidinediones has been developed using dicationic ionic liquid as green medium and catalyst. This method performed well for the condensation of both aryl as well as heteryl aldehydes with 2,4-thiazolidinedione and gave 5-arylidine-2,4-thiazolidinediones with excellent yields.

An efficient and simple one pot method has been developed for the synthesis of 1,4-benzothiazines by allowing the condensation of 2-aminobenzenethiols and 1,3-dicarbonyls using cheaper biocatalyst, baker's yeast. The role of ultrasonication in the rate expediting of the condensation has been discussed.

Cyclocondensation of 2-aminothiophenol and various aryl/heteryl aldehydes was carried in polyethylene glycol-400 as a catalyst and reaction medium at room temperature to obtain 2-aryl substituted benzothiazoles with excellent yields.

Cyclocondensation of 2-aminothiophenol and aryl/heteryl aldehydes has been carried using biomimetic catalyst, β- Cyclodextrin in water and obtained 2-aryl/heteryl benzothiazoles with better to excellent yields. This biomimetic catalyzed route is simple, economic, and environmentally benign.

The condensation of 5-[4′-(2″-halo-ethoxy)benzylidenyl]-2,4-thiazolidinediones 2 when separately carried with different 2-amino thiazoles 3 and different sulphanilamides 4 in DMF, using potassium hydroxide in the presence of a catalytic amount of a phase transfer catalyst, gave new 5-[4′-(4″-aryl-thiazol-2″-yl-aminoethoxy)-3′/5′-substituted benzylidenyl]-2,4-thiazolidinediones 5 and 5-[4′-(2″/4″-sulphonamidophenyl aminoethoxy)-3′/5′-substituted benzylidenyl]-2,4-thiazolidinediones 6 derivatives in good yields, respectively. The structures of all new compounds were established from analytical and spectral data. All the reaction sequences were carried under microwave irradiation, as an efficient tool. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:151–156, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20528

Baker’s yeast catalyzed one-pot three-component cyclocondensation of aryl aldehydes, malononitrile, and β-dicarbonyls in organic medium has been carried out to obtain polyfunctionalized 4H-pyrans. The reaction has been carried out at room temperature in organic solvent, dimethylacetamide and the products obtained in good to moderate yields with simple work up procedure.

An efficient solvent-free cyclocondensation route for condensing mercaptoacetic acid with quinazolinyl-substituted azomethines has been developed using silica chloride as a catalyst for obtaining heteryl-substituted 4-thiazolidinones. The route is found to be rapid, relatively economical, and eco-friendly. The precursors, quinazolinyl azomethines have been obtained in multisteps starting from quinazolinone.

The cyclocondensation of 2-aminothiophenol and aldehydes has been carried out in dichloromethane using bakers’ yeast as a catalyst for obtaining 2-aryl/heteryl benzothiazoles in good yields.

Baker’s yeast catalyzed one-pot three-component cyclocondensation of aryl aldehydes, malononitrile, and β-dicarbonyls in organic medium has been carried out to obtain polyfunctionalized 4H-pyrans. The reaction has been carried out at room temperature in organic solvent, dimethylacetamide and the products obtained in good to moderate yields with simple work up procedure.

Silica chloride catalysted one pot cyclocondensation of aldehydes, ethyl acetoacetate and phenyl hydrazine leading to substituted pyrazoles has been reported.

Title compounds (IV) are conveniently synthesized by a one-pot multicomponent Biginelli reaction using a dicationic ionic liquid as medium and catalyst.

An efficient synthesis of 5-arylidine-2,4-thiazolidinediones has been developed using dicationic ionic liquid as green medium and catalyst. This method performed well for the condensation of both aryl as well as heteryl aldehydes with 2,4-thiazolidinedione and gave 5-arylidine-2,4-thiazolidinediones with excellent yields.

Silica chloride catalysted one pot cyclocondensation of aldehydes, ethyl acetoacetate and phenyl hydrazine leading to substituted pyrazoles has been reported.

Saccharomyces cerevisiae (baker’s yeast) catalyzed one-pot three component cyclocondensation of aryl aldehydes, amines, and thioglycolic acid in organic medium leading to 2,3-diaryl 4-thiazolidinones has been carried out for the first time.

Baker′s yeast offers an eco-friendly protocol for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds.

The title compounds, e.g. (III), are prepared by a simple, economic and environmentally benign procedure.

under microwave irradiation conditions using polyethylene glycol 400 as reaction medium and catalyst

An efficient solvent-free cyclocondensation route for condensing mercaptoacetic acid with quinazolinyl-substituted azomethines has been developed using silica chloride as a catalyst for obtaining heteryl-substituted 4-thiazolidinones. The route is found to be rapid, relatively economical, and eco-friendly. The precursors, quinazolinyl azomethines have been obtained in multisteps starting from quinazolinone.

The condensation of 5-[4′-(2″-halo-ethoxy)benzylidenyl]-2,4-thiazolidinediones 2 when separately carried with different 2-amino thiazoles 3 and different sulphanilamides 4 in DMF, using potassium hydroxide in the presence of a catalytic amount of a phase transfer catalyst, gave new 5-[4′-(4″-aryl-thiazol-2″-yl-aminoethoxy)-3′/5′-substituted benzylidenyl]-2,4-thiazolidinediones 5 and 5-[4′-(2″/4″-sulphonamidophenyl aminoethoxy)-3′/5′-substituted benzylidenyl]-2,4-thiazolidinediones 6 derivatives in good yields, respectively. The structures of all new compounds were established from analytical and spectral data. All the reaction sequences were carried under microwave irradiation, as an efficient tool. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:151–156, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20528

The cyclocondensation of 2-aminothiophenol and aldehydes has been carried out in dichloromethane using bakers’ yeast as a catalyst for obtaining 2-aryl/heteryl benzothiazoles in good yields.

A rapid, solvent free synthetic strategy for the oxidative cyclocondensation of 2-aminobenzenethiols and 1,3-dicarbonyls using a catalytic amount of hydrazine hydrate has been developed in order to obtain 2,3-disubstituted-1,4-benzothiazines in high yields (83–96%).