Thiazolone 3.4- dimethyl

The application of thermolytic reactions (e.g. Diels-Alder and reverse Diels-Alder processes) for the synthesis of fluoro-organic compounds has been reviewed. The cycloaddition of the meso-ionic dithiolone or thiazolone compounds (209 X = S or NPh) with the Diels-Alder adduct of cyclo-octatetraene and dimethyl acetylenedicarboxylate occurs at the cyclobutene ring to give the exo-adducts (210). Pyrolysis of compounds (210) yields dimethyl phthalate and 7,9-diheteratricyclo[4,2, 1,0 ]non-3-en-8-ones (211 X = S or NPh) by retro-[4-t- 2] addition. The similar additions of (209) and related compounds to dimethyl 7-oxabicyclo[2,2,l]-hepta-2,5-diene-2,3-dicarboxylate afforded [4 -1-2] adducts which on pyrolysis suffered double thermal fragmentation e.g. loss of XCO and 3,4-dimethoxycarbonyl-furan) to afford five-membered aromatic heterocyclics. ... 

N,N-Diphenyl-N -(4-phenyl-2-thiazolyl) hydrazine refluxed briefly with p-nitroso-dimethylaniline in glacial acetic acid-ethanol (1 1) 4-phenyl-5-(p-dimethyl-aminophenylimino)-2-thiazolone diphenylhydrazone. Y 94%. F. e. s. H. Beyer, W. Schindler, and K. Leverenz, B. 91, 2438 (1958). 

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