19813-45-7Relevant academic research and scientific papers
The reactivity of (Z)-5-acetyl-3-aryl-2,3-dihydro-2-[(thioacyl)methylene]-1,3,4-thiadiazoles: A surprising base-induced conversion into 3-(N-arylamino)thiophenes
Benincori, Tiziana,Pilati, Tullio,Rizzo, Simona,Sada, Mara,Sannicolo, Franco
, p. 2480 - 2487 (2003)
We report the reactivity shown by two classes of rarely investigated heterocycles, the 5-acetyl-2,3-dihydro-3-phenyl-2-(phenylmethylene)-1,3,4-thiadiazoles (6) and the 5-alkanoyl-3-aryl-2,3-dihydro-2-[(thioacyl)methylene]-1,3,4-thiadiazoles 1a-e. In both cases, strong bases promote cleavage of the thiadiazole ring with loss of thiocyanate anion, generating N-arylketeneimines and N-aryl(thioacyl)keteneimines 5, respectively. These very reactive species undergo either nucleophilic addition or [4+2] cycloaddition reactions involving the thioacyl function. The most surprising result was found in the reactions of the 5-acetyl-3-aryl-2,3-dihydro-2-[(thioacyl)methylene]-1,3,4-thiadiazoles 1a,d,e, which afford 3-(arylamino)thiophenes 2, 10, and 14 as the main products. This serendipitous transformation, which seems to be rather general, probably involves an intermediate step in which the acetyl group of the substrates is converted into ketene. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Reactions of thioesters with organic azides - A novel access to imidates and thioimidates
Mloston,Romanski,Heimgartner
, p. 975 - 982 (2007/10/03)
The reaction of O-methyl thiocarboxylates 8a, b with organic azides at 110°C yielded the corresponding imidates of type 9, which were easily hydrolyzed to give amides 10. The formation of 9 can be rationalized by a 1,3-dipolar cycloaddition of the azide with the C=S group, followed by the "twofold extrusion" of N2 and S. The analogous reaction with methyl dithiobenzoate (11) led to thioimidates 13. On heating, the latter were transformed into thioamides 12.
