A simple efficient and neat synthesis of α-hydroxy phosphonates has been accomplished from aromatic/ heterocyclic aldehydes and diethyl phosphite using KHSO4 as a catalyst under solvent-free conditions at ambient temperature. These compounds are characterized by spectral and analytical data and tested for their anti-oxidant activity.
Coumarin and 7-hydroxy coumarins have great significance as natural fragrances, having a characteristic odour like vanilla beans and their hydroxy position at 7 has importance in biosynthesis. Treatment of 8-formyl-7-hydroxy coumarin with N,Ndisubstituted cyano acetamides in the presence of piperidine afforded novel 8-substituted-7-hydroxy coumarin derivatives. Their structures were characterized by IR, 1 H, 13 C NMR, mass spectral and elemental analysis data. Two out of these 12 compounds, i.e. 2-Cyano-3-(7-hydroxy-2-oxo-2H-chromen-8-yl)-N-[2-(2-methoxy-phenoxy)-ethyl]-acrylamide and 2-Cyano-N-(2,5-dihydro-thiazol-2-yl)-3-(7-hydroxy-2-oxo-2H-chromen-8-yl)-acryl amide showed enhanced in vitro antifungal activity against Candida albicans and Aspergillus niger vis-à-vis standard, i.e. fluconazole, and enhanced in vitro antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa vis-à-vis standard, i.e. norfloxacin.
Aldehydes and ketones undergo smooth coupling with (4E)-3-benzyl-5-phenylpent-4-en-1-ol in the presence of scandium(III) triflate (10 mol%) and 4-toluenesulfonic acid (30 mol%) to give the corresponding trans-fused hexahydro-1H-benzo[g]isochromenes in good yields with excellent selectivity. This is the first example of the synthesis of a trans-fused hexahydro-1H-benzo[g]isochromene derivatives from an aldehyde and (4E)-3-benzyl-5-phenylpent-4-en-1-ol through tandem Prins and Friedel-Crafts cyclizations.
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