Synthesis and characterization of novel pyridyl/naphthyl/(diphenyl) methylseleno substituted alkanoic acids: X-ray structure of 2-pyridylselenoethanoic acid, 2-naphthylselenoethanoic acid and 2-(diphenyl) methylselenoethanoic acid

A number of novel and synthetically important pyridyl/naphthyl/(diphenyl) methylseleno substituted alkanoic acids (20-25) have been synthesized using an efficient and operationally simple strategy. Starting substrates, ethyl pyridyl/naphthyl/(diphenyl) methylseleno substituted alkanoates (8-13) were easily prepared by treatment of ethyl chloroalkanoates 7(a-c) with nucleophilic selenium reagent RSeNa+, generated from the cleavage of dipyridyl/dinaphthyl/bis(diphenylmethyl) diselenide (1-6) with sodium borohydride in ethanol. The ethyl pyridyl/naphthyl/(diphenyl) methylseleno substituted alkanoates (8-13) on basic hydrolysis and subsequent acidification afford pyridyl/naphthyl/(diphenyl) methylseleno substituted alkanoic acids (20-25) in excellent yields. These selenoalkanoates (8-13) and selenoalkanoic acids (20-25) have been characterized by elemental analysis and various spectroscopic techniques viz. NMR (H-1, C-13 and Se-77), IR and mass spectrometry. The molecular structure of 2-pyridylselenoethanoic acid (20a), 2-naphthylselenoethanoic acid (23a) and 2-(diphenyl) methylselenoethanoic acid (24a) has also been established with the help of single crystal X-ray analysis. (C) 2008 Elsevier B. V. All rights reserved.