Utility and Synthetic Uses of Mannich Reaction: An Efficient Route for Synthesis of Thiadiazino‐[1,3,5][3,2‐a]benzimidazoles

The Mannich reaction in the synthesis of N,S-containing heterocycles. 7. Effective one-pot synthesis of derivatives of spiro[3,5,7,11-tetraazatricyclo-[7.3.1.02,7]tridec-2-ene-13,4′-piperidine]

“…It follows from multitudinous data in the literature that aminomethylation of 2-mercaptoazoles and -azines is a general method for the preparation of condensed derivatives of 1,3,5-thiadazines. In particular, derivatives of sym-triazolo [3,4-b][1, 3,5]thiadiazine [9][10][11][12][13][14][15][16], thiazolo [3',4':1,5][1,2,4]triazolo [3,4-b][1, 3,5]thiadiazine [17], imidazo[2,1-b][1, 3,5]thiadiazine [18,19], 1,2,4-triazino [3,2- 3,5]thiadiazine [19], and 1,3,5-thiadiazino[3,2-a]benzimidazole [20] have been obtained by "double" Mannich condensations. We have shown previously with a series of 2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates that, depending on the structure of the substrate, aminomethylation can lead to the formation of _______ * For 3,5]thiadiazine [21,22], 3,7-diazabicyclo[3.3.1]nonane [23], or tricyclic products [24].…”

Synthesis of partially hydrogenated 1,3,5-thiadiazines by Mannich reaction

“…Chemistry of Heterocyclic Compounds 2015, 51 (2), [109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] were observed, and the major products were dithiazines 20. Aniline and meta-substituted anilines under these conditions tended to form mixtures of compounds 13, 20, and 22 in various ratios (Scheme 5), with the fraction of dithiazines 20 increasing after longer reaction time; complete conversion of amine was achieved after 10 h. In general, it was noted 37а that 3,5-diaryl-substituted perhydro-1,3,5-thiadiazines were more stable than 3,5-dialkyl analogs, which readily disproportionated with the formation of dithiazines.…”

“…The reaction was sensitive both to the reactant ratio and reaction temperature, as well as the amount of catalyst used. Derivatives of perhydro-1,3,5-thiadiazine 38 could be Chemistry of Heterocyclic Compounds 2015, 51 (2), [109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] obtained in up to 66% yield by heating (thio)urea with a mixture of CH 2 O and H 2 S (1 : 2 : 1 ratio) in the presence of n-BuONa (4 equiv) (Scheme 12). 43,84 It has been noted 43 that mostly macrocyclic condensation products were obtained under different conditions.…”

“…The attempts to transform the latter into thiadiazines by the action of excess CH 2 O over a wide range of рН or treatment with CH 2 Cl 2 in the presence of bases were not successful. 117 Among the reactions of other condensed However, we should note that the synthesis of 1,3,5-thiadiazines from derivatives of cyanopyridine-2-thiolate and the respective thiones is not universally applicable. For example, structural analogs of thiolate 77, containing strong electron-withdrawing substituents (CN, CO 2 R) at position 5, did not produce pyridothiadiazine derivatives under the indicated conditions, probably due to the decreased nucleophilicity of sulfur atom.…”

“…15 The most widely used compound of THTT series is 3,5-dimethyltetrahydro-1,3,5-thiadiazine-2-thione (5), known by the trade names Dazomet, Tiazone (in USSR), Basamid, Mylone, DMTT, and applied as highly potent soil fumigant, fungicide, herbicide, and powerful insecticide, as well as for the prevention of biofilm accumulation in paper industry. 16 Chemistry of Heterocyclic Compounds 2015, 51 (2), [109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] Translated from Khimiya Geterotsiklicheskikh Soedinenii, 2015, 51 (2), [109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] rapidly decomposes by forming MeNCS, MeNH 2 , СН 2 О, and Н 2 S, which provide for its fumigant activity. 18, 19 It has also been reported that thiazone 5 has ovicidal activity against...…”