Synthesis and Characterization of Some New 1-(3-(heterocyclic-2-yl)-4,5-dihydroisoxazol-5-yl)Pentane-1,2,3,4,5-Pentaol Derivatives from New Chalcone

The synthesis and characterization of some novel chalcone and isoxazole derivatives has been presented. Isoxazoles (D-F) have been prepared from chalcones (A-C) by treating with hydroxylamine hydrochloride . The structure of isoxazoles has been characterized by spectral analysis by FT-IR and 1 H NMR spectroscopy.


Introduction
Heterocyclic compounds are very widely distributed in nature, and are essential to life in various ways. Particularly these compounds are important because of the wide variety of physiological activities associated with this class of substances. Heterocyclic rings are present in several compounds, e. g, most of the members of vitamin B complex, antibiotics, chlorophyll, haemin, other plant pigments, amino acids and proteins, drugs, dye stuffs, enzymes, the genetic material DNA etc.
The paramount importance of heterocycles in nature product chemistry and pharmacology constantly drive the search for new methods for the construction of heterocyclic unit viz., isoxazoles and pyrazoles. These isoxazoles and pyrazoles were prepared from chalcones which are important intermediate products and they also possess biological and pharmacological activities [1] .

Experimental
General. IR spectra recorded on FT.IR SHIMADZU model 8400,. 1 H NMR spectra were acquired with a SHIMADZU ( 1 HNMR : 400 MHz) (University of Tahran ,Iran). The chemical shifts were referenced to tetra methyl silane (TMS) as an internal reference. Mass spectra were acquired with a SHIMADZU (University of Tahran ,Iran).

Synthesis of chalcone derivatives (A-C)
General procedure. A mixture of glucose (0.05) mole with (0.005) mole of 2-acetyl heterocyclic derivatives were dissolved in ethanolic sodium hydroxide (10 ml) the mixture was stering for 3 hrs.. The precipitate obtained was filtered, washed and recrystallized from ethanol. To afford the pure products (A-C).

Results and discussion
Treatment of 2-acetyl heterocyclic derivatives with glucose in boiling ethanol gave chalcone derivatives (A-C) (scheme 1) in (80-87)% yield. The structures of these derivatives were characterized from their FT-IR and 1 H NMR spectra. The FT-IR spectra of chalcone compounds (A-C) were characterized by the appearance of the absorption band of chalcone that was attributed to the (C=C) stretching which appeared at (1566-1600) cm -1 These fact confirmed the correct expected chemical structure of these compounds. All the IR spectra of chalcone compounds (A-C) showed a band at (1662-1674) cm -1 which related to (C=O) stretching of chalcone , The OH stretching of glucose showed a band within the range (3417-3448) cm -1 .