Zur Chemoselektivität der Reaktion von 2,4‐disubstituierten Thiosemicarbaziden mit Carbonylverbindungen — eine neue Synthese von Triazolidin‐3‐thionen

Novel Synthesis of 1,3‐Thiazine and Pyrimidinethione Derivatives from (1‐Aryl ethylidene)hydrazinecarbothioamides and Tetracyanoethylene

“…Sharp singlet signal with three protons resonates at 2.34 ppm, because of methyl group, in addition to the phenyl protons at 7.36–7.93 ppm. The 13 C NMR spectra of the isolated products 7a , 7b , 7c confirmed the absence of CS signals but revealed the following signals (for example 7a ) 115.83, 116.57 ppm (cyano groups at thiazine‐C‐5 and C‐6), 158.77 ppm (external CN), 162.07 ppm (thiazine‐C‐2), 20.87 (thiazine‐C‐6), thiazine‐C‐4 and C‐5 resonate at 59.82 and 166.25 ppm, respectively are in accordance with the observed trends in δ values for C‐atoms in push–pull alkenes . The mass spectrometry fragmentation of isolated products 7a , 7b , 7c was studied under electron ionization.…”

Synthesis of Spiro(indenepyrazole) and Indenotriazinone Derivatives from 4-substituted Thiosemicarbazides and (1,3-dioxo-2,3-dihydro-1H-Inden-2-Ylidene)Propanedinitrile

“…A value which should be expected for structure 9 is 4.5 ppm as given in the literature. 27 On the other hand, the 1 H-NMR spectrum of 7a shows the presence of pyrazole-NH at (δ H = 10.95 ppm) due to cojungation with π-system. Furthermore, in the 13 C NMR of 7a-f, the pyrazole-C-5′ is regularly downfield shifted [7a (C-5′ = 174.68), 7b (C-5′ = 173.66), 7c (C-5′ = 170.31), 7d (C-5′ = 173.65), 7e (C-5′ = 173.54), 7f (C-5′ = 172.82) compared to pyrazole-C-3′ in compounds 9 (which has been resonated with range 158.45-158.64).…”

Thiosemicarbazides in heterocyclization

“…Heating of substituted thiosemicarbazide 1 in ethanol in presence of sodium ethoxide gave the corresponding 4 H ‐5‐mercapto‐3‐phenyl‐1,2,4‐triazole 154 in good yield [96]. …”