Studies of heterocyclic compounds. Part 26. Synthesis of 1,6,6aλ⁴-triheterapentalenes from isothiazole-5-carbaldehyde

Fused 1,2,3‐Thiadiazoles

“…75 Stable 1:1 complexes between these compounds 200 and 1,3,5-trinitrobenzene were obtained. Methylation of 199 with methyl fluorosulfonate furnished the thiatriazapentalene 200 in excellent yield.…”

Base-induced reactions of isothiazolium salts with active 5-methyl or 5-methylene groups

“…The comparison of various spectroscopic data with those of typical thiadiazapentalenes shows that all compounds 5 obtained by our synthesis retain the same basic structural features independent of the substituents on the phenyl rings. Apart from the correct elemental analyses, 'H-NMR shows the signals for the proton in 6-position in a range of S = 7.9-8.1 pprn as it is typical for thiadiazapentalenes [1,9]. The main characteristics of the 13C-spectra are given by the chemical shifts for the signals of the C-3 and C-3b atoms, which are at relatively high field between S = 109.3-112.3 ppm and 6 = 110.…”

“…Yield ( 9, 23.4, 26.2, 27.4 (d, C-5,6,7,8) 1 -(4-Bromophenyl)-3-methyl-9-phenyl[4,5,6,7/-tetrahydrobenzo[d]thieno[3,2,- (9,22.9,23.4,26.2,27.4 (t,6,7,8) WI.…”

Oximes of five-membered heterocyclic compounds with two heteroatoms 2. Reactions and biological activity (Review)

“…In aqueous sodium carbonate the para-toluenesulfonate of isothiazole oxime 64 gives the bicyclic product 65 with a yield of 87% [110]. Heterocyclic systems containing an isoxazole and pyrazole (or imidazole) fragment were obtained successfully from pyrazole and imidazole oximes (111)(112)(113)(114).…”