Preparation and characterization spiro-benzoisothiazole-pyrazoles, spiro-benzoisothiazole-isoxazoles, and pyrazole-benzenesulfonamides from dilithiated hydrazones or dilithiated oximes with methyl 2-(aminosulfonyl)benzoate

WCC 14

Anna C. Dawsey1, Charles F. Beam1, John D. Knight, jdknight@edisto.cofc.edu1, Clyde Metz, metzc@cofc.edu1, and William T. Pennington Jr., BILLP@exchange.clemson.edu2. (1) Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424, (2) Department of Chemistry, Clemson University, Hunter Research Laboratories, Clemson, SC 29634-0973
Several 1,4-dianion type activated intermediates were condensed-cyclized with methyl 2-(aminosulfonyl)benzoate to afford spiro-azoles or pyrazole-benzenesulfonamides: [1] dilithiated C(alpha), N-carbomethoxyhydrazones were condensed with methyl 2-(aminosulfonyl)benzoate to afford intermediates that were isolated and not characterized but cyclized with acetic anhydride to spiro-benzoisothiazole-pyrazoles, which also included an N-acetylation; [2] dilithiated C(alpha),N-carbo-tert-butoxyhydrazones were treated with methyl 2-(aminosulfonyl)benzoate followed by cyclization with 6 M hydrochloric acid, hydrolysis and decarboxylation to give NH-pyrazole-benzenesulfonamides; [3] dilithiated C(alpha),N-phenylhydrazones were condensed with methyl 2-(aminosulfonyl)benzoate, followed by cyclization with 3M hydrochloric acid afforded N-phenylpyrazole-benzenesulfonamides; and [4] dilithiated C(alpha),O-oximes were treated with methyl 2-(aminosulfonyl)benzoate, followed by cyclization with 3 M hydrochloric acid, and spiro-benzoisothiazole-isoxazoles resulted.

The structural elucidation of the spiro-azoles and pyrazole-benzenesulfonamides products was based upon absorption spectra and confirmed by X-ray crystallographic analysis. Mechanistic intermediates to describe the reaction may include C-acylated intermediates that cyclize to spiro-azoles or pyrazole-benzenesulfonamides.

 

The Merck Index Women in Chemistry
2:30 PM-4:30 PM, Monday, August 18, 2008 Pennsylvania Convention Center -- Hall C, Poster

Women Chemists Committee

The 236th ACS National Meeting, Philadelphia, PA, August 17-21, 2008