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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.

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. &nbsp

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.

Substituted phenacyl chlorides (1a–f) were cyclocondensed with nucleophiles thiourea (2a) and thiobenzamide (2b) in presence of baker’s yeast (Saccharomyces cerevisiae) as whole-cell enzyme source in acetonitrile at room temperature to obtain 4-(4-substituted phenyl)thiazol-2-amines (3a–f) and 4-(substituted phenyl)-2-phenylthiazoles (4a–f), respectively. Moreover, substituted phenacyl chlorides also reacted with nucleophiles 2-amino-1,3,4-thiadiazole (2c), o-phenylenediamine (2d), 1-amino-2-mercapto-5-phenyl triazole (2e), and pyridin-2-amine (2f) at room temperature in presence of baker’s yeast to give fused heterocycles 6-(4-substituted phenyl)-2-phenylimidazo[2,1-b][1,3,4]thiadiazoles (5a–f), 2-(4-substituted phenyl)quinoxalines (6a–f), 6-(4-substituted phenyl)-3-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines (7a–f), and 2-(4-substituted phenyl)H-imidazo[1,2-a]pyridines (8a–f), respectively. The experimental conditions for these cyclocondensations were optimized to obtain the biodynamic heterocycles in high yield. The unique features of this work are use of baker’s yeast as a cheap and readily available natural source of biocatalyst, noticeable rate acceleration, convenient route to products, cost effectiveness, and scalability.

In a search of new potentially active antitubercular agents here we have synthesized 3-substituted phenyl-2-(4-(tetrazolo[1,5-a]quinolin-4-ylmethoxy)phenyl)thiazolidin-4-ones (8a–l) and evaluated their antibacterial, particularly antitubercular activity. These have been conveniently synthesized by performing one–pot cyclocondensation of 4-(tetrazolo[1,5-a]quinolin-4-ylmethoxy)benzaldehyde, anilines and mercaptoacetic acid in dicationic ionic liquid, (3-methyl-1-[3-(methyl-1H-imidazolium-1-yl)propyl]-1H-imidazolium dibromide [C3(MIM)2–2Br]) and obtained excellent yields of (8a–l). 4-Thiazolidinones (8a–l) were thoroughly characterized by their spectral analyses. These compounds have been screened for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Ra and Mycobacterium bovis (BCG). The compounds 8a, 8c, and 8e exhibited notable in vitro antitubercular activity compare to the reference, Rifampicin. Molecular docking study has also been performed to know the binding mode of these analogs in to the active site of DprE1 enzyme. The synthesized compounds were also evaluated for their in vitro antibacterial activity and amongst them compound 8k has shown moderate activity against both gram-negative and gram-positive bacterial strains.

New bithiazolyl hydrazones (6a-l) have been first time synthesized by carrying novel one pot cyclocondensation of 5-acyl thiazoles (1a-b), thiosemicarbazide (2) and substituted phenacyl chlorides (4a-f) in freshly prepared ionic liquid, diisopropyl ethyl ammonium acetate (DIPEAc) at room temperature. The newly synthesized compounds have been evaluated for their antitubercular activity and the compounds 3b, 6a, 6b, 6d, 6e, 6f, 6g, and 6l have displayed noticeable antitubercular activity compared to Rifampicin with tolerable cytotoxicity. All these compounds were also screened for their antibacterial activity and found that, compounds 6j and 6k have exhibited a very good antibacterial activity. Molecular docking study has shown better harmony with the evaluation trend shown by these compounds under in vitro antitubercular screening.

Amino pyrimidines have been synthesized by a one-pot procedure under environmentally friendly reaction conditions at room temperature. The use of aqueous PEG-400 circumvents the problems associated with the toxic, hazardous organic solvents and oxidizing agents.

We report synthesis and in vivo antihyperglycemic evaluation of new 3-substituted phenyl-2-(4-(tetrazolo[1,5-a]quinolin-4-ylmethoxy)phenyl)thiazolidin-4-ones (8a–l). The title 4-thiazolidinones were synthesized by one-pot cyclocondensation of new 4-(tetrazolo[1,5-a]quinolin-4-ylmethoxy)benzaldehyde (5), anilines, and mercaptoacetic acid in PEG-400. The required aldehyde (5) was also synthesized, starting from 2-chloroquinoline-3-carbaldehyde via a successive multistep route. The newly synthesized products were thoroughly characterized based on their spectral data. Amongst them, compounds 8a–g, j exhibited notable in vivo antihyperglycemic activity. Compounds 8f, g showed percentage improvement in oral glucose tolerance of 18.9 and 20.7, respectively, compared with 28.3 for the reference metformin.

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.

Emergence of multidrug resistant and extensively drug resistant tuberculosis has prompted to develop new molecular entities to treat the disease. A series of new 4-thiazolidinones with pyrazinyl and thiazolyl scaffolds has been synthesized, and their antitubercular activity is reported. The title 4-thiazolidinones, N-(pyrazinyl substituted thiazoloylamino)-2-aryl-4-thiazolidinones (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) have been first time prepared using pyrazinamide as a starting material via five successive steps. The purity and the structures of the intermediates (carboethoxythiazole, acid hydrazide, and azomethines) and title thiazolidinones (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) have been confirmed by TLC and spectral analyses, respectively. An antitubercular screening of the new 4-thiazolidinones has been performed on bacterial strains, Mycobacterium tuberculosis H37Ra and Mycobacterium BCG using the solutions of different concentrations of the compounds (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) and the screening results are presented. Compound 6a has displayed notable antitubercular activity.

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.

New trisubstituted pyrazoles bearing thiazolyl and thiazolidinonyl moieties have been successfully and conveniently synthesized in three steps using 5-acetyl thiazoles (1a–b) as starting materials. The route includes the synthesis of new intermediates, 4-formyl 5-thiazolyl pyrazoles (4a–b). The formyl pyrazoles on one pot cyclocondensation with anilines and thioglycolic acid have been found to yield the titled compounds (7a–j). The new pyrazoles have been screened to evaluate in vivo anti-inflammatory activity and compounds 7c, 7d, 7f, 7g, 7h, and 7i have better anti-inflammatory activity than reference drug Celecoxib. The synthetic details and results of anti-inflammatory activity are discussed.

Here we report a novel Baker yeast catalysed one pot cyclocondensation, carried at room temperature in ethanol for obtaining high yields of polyfunctionalised pyridines, 2-amino-4-aryl-3,5-dicyano-6-phenylthio-pyridines. The developed protocol obeys certain green principles and is scalable and cost effective.

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.

A simple and efficient protocol developed for the synthesis of 5-substituted 1H-tetrazole derivatives via [2 + 3] cycloaddition reaction between benzonitriles and sodium azide using diisopropyl ethylammonium 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.

Background: 2, 4-Thiazolidinedione (TZD), pyrazole and thiazole heterocyclic rings exhibit a wide range of pharmacological activities. Medicinal chemists use these heterocyclic moieties as scaffolds in drug designing and discovery. The existing medicaments, celecoxib and meloxicam, used for treating inflammation and pain are having, pyrazole and thiazole, respectively as key scaffolds. Pyrazoles coupled with 2, 4-thiazolidinediones may display enhanced anti-inflammatory activity. With this hope the bench work was carried out. Methods: Heterocyclic aldehydes, 3-(4-methyl-2-substituted thiazol-5-yl)-1-phenyl-1Hpyrazole- 4- carbaldehydes (4a-b) have been allowed to undergo Knoevenagel condensation with N-substituted 2,4-thiazolidinediones (5a-e) in PEG-400 in the presence of L-proline at 110°C and obtained the condensed products (6a-j). COX-2 evaluation of the titled product has been carried out using in vitro COX-2 ELISA Kit. Antibacterial activity of these compounds (6a-j) has also been determined. Results: On the basis of 1H NMR, 13C NMR and Mass spectral data of the condensed products the structures have been assigned to (Z)-5-((3-(4-methyl-2-substituted thiazol-5-yl)-1- phenyl-1H-pyrazol-4-yl)methylene) 3-substituted thiazolidine-2,4-diones (6a-j). Among the evaluated compounds (6a-j), 6f, 6g, 6h, 6i and 6j have shown notable COX-2 inhibitory activity. Conclusion: Compounds, 6a, 6b, 6c, 6d, 6e and 6f have inhibited the growth of the Bacillus cereus NCIM 2106, Bacillus subtilis NCIM 2063, Pseudomonas aeruginosa NCIM 2074, Salmonella typhimurium NCIM 2501 and Staphylococcus aureus NCIM 2079. However, compound 6f has emerged as a suitable candidate with dual properties i.e. COX-2 inhibitory and antibacterial in the present study.

Amino pyrimidines have been synthesized by a one-pot procedure under environmentally friendly reaction conditions at room temperature. The use of aqueous PEG-400 circumvents the problems associated with the toxic, hazardous organic solvents and oxidizing agents.

The environmentally friendly ultrasound promoted method offers several advantages such as operational simplicity, easy work-up procedure, shorter reaction times, and high yields.

A convenient synthetic route has been developed to synthesize 5-(4-((2-phenylthiazol-4-yl) methoxy)phenyl)3-(4-sustituted phenyl)pyrazolines (5a-f) and 5-(4-((2-phenylthiazol-4-yl)methoxy)phenyl)-3-(4-substituted phenyl)isoxazolines (6a-f) starting from 2-phenyl-4-chloromethylthiazole (1). The chloromethylthiazole (1) was first condensed with 4-hydroxy benzaldehyde (2) for obtaining 4-((2-phenylthiazol-4-yl)methoxy)benzaldehyde (3). Claisen-Smidth condensation of 4-((2-phenylthiazol-4-yl)methoxy)benzaldehyde (3) and acetophenones has been carried in alkaline alcohol and obtained 3-(4-((2-phenylthiazol-4-yl)methoxy)phenyl)-1-(4substituted phenyl)prop-2-en-1-ones (4a-f). The cyclocondensation of 2-propen-1-ones has been first time carried separately with hydrazine hydrate and hydroxylamine hydrochloride in aqueous micellar tetradecyltrimethylammonium bromide (TTAB) medium for getting the titled heterocycles with good to excellent yields.

A convenient and scalable four-step novel route has been developed for the synthesis of rosiglitazone (8), an antidiabetic drug. This multistep route requires 4-fluoro benzaldehyde (4), 2,4-thiazolidinedione (6) and 2-chloro pyridine (1) as key reactants and gives overall better yield of rosiglitazone. In addition, some steps have been accelerated, which leads to an overall time saving of 10h.

An efficient one-pot three-component cyclocondensation of 4-(p-toulyl sulfonoxy) benzaldehyde, aryl amines, and mercaptoacetic acid in polyethylene glycol 400 (PEG-400) was conducted to obtain new 2,3-disubstituted-4-thiazolidinones. This route is economical and ecofriendly. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:166–170, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20766

A convenient multi step synthetic protocol for new dihydropyrimidinones bearing quinolynyl methoxy phenyl moiety has been developed from 2-chloro-3-formyl quinolines. The last step is one-pot Big- inelli reaction of multicomponents, 4-((2-chloroquinolin-3-yl) methoxy) benzaldehydes, ethyl acetoacetate and urea mediated and catalysed by dicationic ionic liquid (3-methyl-1-(3-(methyl-1H-imidazolium-1-yl) propyl)- 1H-imidazolium dibromide (C3 (min)2 2( Br − ) )). Simple work-up procedures and moderate to good yields of the pyrimidinones and the intermediates are the merits of the route.

Synthetic route has been developed for the synthesis of new (Z)-5-[4-(2-chloroquinolin-3-yl) methoxy]benzyl-idinethiazolidine-2,4-diones (6a-h) starting from 2-chloro-3-hydroxymethyl quinolines (2a-h). The hydroxy methyl quinolines on tosylation yielded (3a-h). Condensation of the tosyl intermediates with 4-hydroxy benzaldehydes has been carried in DMF in presence of and obtained 4-quinolinyl methoxy benzaldehydes (4a-h). Conveniently Knoevenagel condensation of quinolinyl methoxy benzaldehydes (4a-h) and 2, 4-thiazolidinedione (5) has been carried in PEG-400 in presence of L-proline and obtained better yields of the titled compounds (6a-h).

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.

A convenient one-pot, three-component cyclocondensation mediated by ionic liquid for obtaining 2,3-disubstituted-4-thiazolidinones with excellent yields is reported.

There is no report on the synthesis of 2,4-thiazolidinediones bearing heteryl substituents like, piperidinyl quinolines. Keep-ing the above potent usefulness of the heterocycles in mind, here it was thought worthwhile to synthesize the titled, new quinolidinyl 2,4-thiazolidinediones with hope to obtain the molecules with potential hypoglycemic activity by developing a convenient synthetic route using readily available starting materials. It has also been reported

A facile one-pot synthesis of 2-aminothiazoles has been carried in PEG-400 as a greener medium at room temperature. This method avoids the use of lachrymatric α-bromoketones as well as the volatile, toxic organic solvents.

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

Knoevenagel condensation of various aromatic aldehydes with 2,4-thiazolidinedione has been carried out in polyethylene glycol-300. The reactions were carried out at moderate temperature with very simple isolation procedure and with better yields.

Rapid, quantitative and regioselective O-acylation/O-benzoylation of hydroxamic acids has been carried using polymer supported hydroxamate anions and acetyl/benzoyl chloride under mild conditions. The isolation of unambiguous and pure products by simple work-up is also an important feature of this method.

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.

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.

First time one-pot water-mediated synthetic route has been developed by carrying condensation of 2-chloro-3-formyl quinolines and hydrazine hydrate/phenyl hydrazine using thermal/microwave energy resources. The route is convenient, eco-friendly, and scalable.

However, these me-thods often require long reaction times and high temperature.Considering the biological significance of the oxadiazoles and need to develop an efficient route for the oxadiazoles here in the present work an attempt has been made to provide one pot method for obtaining new oxadiazoles bearing sulph- onamido phenyl pharmacophore. Therefore here we report an efficient synthesis of

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.

In the search of new antihyperglycemic agents and following rational approach of drug designing here new 2-hydrazolyl-4-thiazolidinone-5-carboxylic acids ( 4a – g ) with pyrazolyl pharmacophore have been synthesized via thia Michael addition reaction of 1-((3-(4-substituted phenyl)-1-phenyl-1 H -pyrazol-4-yl)methylene)thiosemicarbazides ( 3a – g ) with maleic anhydride. The required precursors, ( 3a – g ) were obtained by condensing known 3-(4-substituted phenyl)-1-phenyl-1 H -pyrazole-4-carbaldehydes ( 1a – g ) with thiosemicarbazide in ethanol. The newly synthesized compounds ( 4a – g ) have been evaluated for the antihyperglycemic activity in sucrose loaded rat model and among these compounds 4d , 4f and 4g have displayed significant antihyperglycemic activity.

A convenient and scalable novel route to the antidiabetic drug rosiglitazone (VI) is presented.

An efficient one-pot three-component cyclocondensation of 4-(p-toulyl sulfonoxy) benzaldehyde, aryl amines, and mercaptoacetic acid in polyethylene glycol 400 (PEG-400) was conducted to obtain new 2,3-disubstituted-4-thiazolidinones. This route is economical and ecofriendly. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:166–170, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20766