Synthesis and Reactivity of N-Vinyl-1,2,3-dithiazolimines

Synthesis of condensed thiazoles. (Review)

“…The synthesis of pyrrolothiazines 93 and 94 with good yields (80%) from mercaptopyrrole 92 with phenyl isocyanate and p-chlorobenzoyl chloride has also been used [63]. As also in the case of thienothiazoles [57,58], one of the most attractive general methods for the synthesis of pyrrolothiazines is the oxidation of the corresponding monothiooxamides with K 3 [Fe(CN) 6 ] in alkaline solutions. This method was used for the creation of a thiazole ring based on aminopyrroles.…”

“…The thiazolopyridines 142-144 were obtained by oxidation of the pyridine 141 with potassium hexacyanoferrate in an alkaline medium [100]. As in the case of the synthesis of thienothiazoles [57,58], this method can be applied more successfully to the cyclization of monothiooxamides of the pyridine series. Thus, it was used for the production of thiazolo [4,5-b]-and thiazolo [5,4-b]pyridine-2-carboxamides.…”

“…The latter are easily obtained during the reaction of a wide range of amines with chloroacetamides and sulfur in the presence of triethylamine by a modification of the procedure in [49][50][51][52][53][54][55].…”

“…[Fe(CN) 6 ] at 20°C led to good yields of the 2-carbamoylthieno[3,2-d]thiazoles 73[57]. carboxy-2-methylthiophene (74b), including the production of the intermediate 2-aminothiophenes 75[79], was likewise described in[58].The authors point out that the cyclization of the monothiooximes 76 to the thiazole system takes place at 0°C in a 2% solution of sodium hydroxide, and the 2-carbamoylthieno[2,3-d]thiazoles 77 are formed with satisfactory yields[58].…”

Quantum-chemical study of the electronic structure and reactivity of 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylic acid methyl ester

“…An attractive method for adding functional groups to thienopyrroles is to introduce acyl groups which then can be converted to various functional groups, including heterocyclic moieties. However, a serious and poorly studied problem is how to carry out regioselective reactions with thienopyrroles having free positions on both the thiophene ring and the pyrrole ring.Earlier we showed that in the presence of a two-fold excess of AlCl 3 , acylation of 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylic methyl ester (1) occurs regioselectively at the 3 position of the diheterocycle, yielding the product 2, while when equimolar amounts of AlCl 3 and thienopyrrole are used, a mixture of 3-and 6-acyl derivatives 2 and 3 is formed (Scheme 1) [4].With the aim of estimating the effect of structural and electronic factors on the selectivity of acylation, in this paper we compare the calculated heats of reaction and the experimentally established percentages of isomers formed, and also the calculated electron density distributions in complexes of thienopyrrole with AlCl 3 and possible routes for electrophilic attack in nonpolar and polar solvents.The calculations were performed using the MOPAC program [5] by the standard semiempirical quantum-chemical method MNDO with full optimization of the geometry for the molecules of thienopyrrole 1, monoketones 2, 3, complexes with aluminum chloride 4-8, and σ-complexes 9, 10 (Scheme 2). …”