Synthesis of thiadiazabicyclane and bis-1,3,5-dithiazinane by cyclothiomethylation of aliphatic diamines with CH2O and H2S

Cyclocondensation of aliphatic diamines with CH₂O and H₂S (1:3:2 ratio, 0 °C) was carried out to give thiadiazabicyclanes and dithiadiazabicyclanes (1:6:4 ratio), which were previously difficult to synthesize. Symmetric α,ω-bis-1,3,5-dithiazinanes were synthesized at 80 °C by this reaction. The stereochemistry of thiadiazabicyclanes was assigned by ¹H and ¹³C NMR spectroscopy and by theoretical DFT calculations, and of bis-dithiazinanes by X-ray diffraction study in the solid state.     

Stereoelectronic effects in N-C-S and N-N-C systems: experimental and ab initio AIM study

The energy of stereoelectronic interactions in N-C-S and N-N-C systems in tetrahydro[1,3,4]thiadiazolo[3,4- c][1,3,4]thiadiazole was estimated by means of R. W. Bader's quantum theory of "atoms in molecules" (AIM) and natural bond orbital analysis (NBO). The results were compared with those obtained by analysis of rho( r) derived from high-resolution X-ray diffraction data. The analysis of the data obtained allowed one to find a correlation between geometric characteristics of the stereoelectronic interactions, NBO mixing energies and the AIM properties of atoms. Significant variations of nitrogen atom atomic basin populations in different conformers were explained by sterical interactions between their electron lone pairs.     

Cyclothiomethylation of primary amines with formaldehyde and hydrogen sulfide to nitrogen- and sulfur-containing heterocycles (review)

Published data and the authors' own experimental results on the synthesis of nitrogen- and sulfur-containing heterocycles based on the cyclothiomethylation of amines with formaldehyde and H₂S are reviewed. Features of the three-component condensation are discussed in relation to the nature and structure of the initial amines and also the reaction conditions.     

Heterocyclization of hydrazine with acetaldehyde and H2S

Hydrazine is regioselectively condensed with a mixture of acetaldehyde and H₂S at a temperature below −10 °C to form 2,4,6,8-tetramethyl-3,7-dithia-1,5-diazabicyclo[3.3.0]-octane. The reaction at 0 °C with the reverse order of mixing of the starting reagents affords 2,4,6-trimethyl(1,3,5-dithiazinan-5-yl)amine as the major product.     

Thiomethylation of amino alcohols using formaldehyde and hydrogen sulfide

Three-component condensations of formaldehyde with hydrogen sulfide and hydroxylamine or amino alcohols at a ratio of 3:2:1 give 47–73% of N-hydroxy(or hydroxyalkyl)-1,3,5-dithiazinanes. The reactions of CH₂O with H₂S and hydroxylamine or α-amino alcohols at a ratio of 4:3:1 involve both amino and hydroxy groups, leading to the corresponding dithiazinanes. 4-Aminobutan-1-ol reacts with CH₂O and H₂S under analogous conditions only at the amino group to form 4-(1,3,5-dithiazinan-5-yl)butan-1-ol.     

Multicomponent condensation of aliphatic amines with formaldehyde and hydrogen sulfide

Cyclothiomethylation of primary aliphatic amines with the reagent H₂S-CH₂O (2:3) in aqueous medium mainly gave substituted dithiazines; oxathiazines and dioxazines were obtained from butylamine and ethanolamine. Under the chosen reaction conditions, ethylenediamine was converted into 5-[2-(perhydro-1,3,5-dithiazin-5-yl)ethyl]perhydro-1,3,5-dithiazine or substituted thiazetidine and oxazetidine, depending on the order of mixing of the starting reagents.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 423–427, February, 2005.     

Cyclothiomethylation of aryl hydrazines with formaldehyde and hydrogen sulfide

Cyclothiomethylation of phenyl hydrazine with CH₂O and H₂S in a ratio of 1: 3: 2 in an acidic medium (HCl) afforded previously unknown 3-phenyl-1,3,4-thiadiazolidine (35% yield) and N-phenyl(perhydro-1,3,5-dithiazin-5-yl)amine (35% yield). The analogous reaction in an alkaline medium (BuONa) produced N-phenyl(perhydro-1,3-thiazetidin-3-yl)amine (22% yield). The reaction of 1,2-diphenyl hydrazine with CH₂O and H₂S in an alkaline medium gave 1,2,4,5-tetraphenylhexahydro-1,2,4,5-tetrazine and previously unknown 3,4-diphenyl-1,3,4-thiadiazolidine and 5,6-diphenyltetrahydro-1,3,5,6-dithiadiazepine in 39 and 22% yields, respectively. Cyclothiomethylation of benzyl hydrazine afforded previously unknown bis[(6-benzyl-4,2,6-thiadiazolidin-2-yl)methyl] sulfide (60% yield) and N-benzyl(perhydro-1,3,5-dithiazin-5-yl)amine (19% yield). The reaction of tosyl hydrazine produced 3-[(p-tolyl)sulfonyl]-1,3,4-thiadiazolidine, N-(perhydro-1,3,5-dithiazin-5-yl)-p-tolylsulfonamide, and 3,7-bis(p-tolylsulfonylamino)-1,5-dithia-3,7-diazacyclooctane in 21, 38, and 41% yields, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1758–1767, October, 2006.     

Multicomponent heterocyclization of carboxamides with H2S and CH2O

Multicomponent heterocyclization of aliphatic amides with H₂S and CH₂O (1:3:2) in water-organic solvent mixture in the presence of BuONa led to the formation of 1,3,5-dithiazinane in high yield (30–95%) and with high selectivity (100%). Under these conditions benzamide gave 3,5-dibenzoyl-1,3,5-thiadiazinane in 74% yield, whereas due to ortho-effect the acetylsalicylamide with H₂S and CH₂O in a system BuOH-H₂O without BuONa formed N-acetylsalicyloyl-1,3,5-dithiazinane (80%). Heterocyclization of α-aminosuccinic acid monoamide depending on the H₂S and CH₂O concentration occurred either at one or both NH₂ yielding respectively mono-or bisdithiazinanes.