A Novel Conversion of 3,7-Disubstituted 2H,6H-Tetrahydro-1,5,3,7-diselenadiazocines to 4-Substituted 1,2,4-Diselenazolidines by Treating with Oxidizing Agents

Abstract

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1,2-Dications in Organic Main Group Systems

“…Dealkylation of intermediate diselenonium dication 164 was suggested as the key step in the oxidative synthesis of 1,2,4-diselenazolidines 165 from eight-membered heterocycles 163 …”

“…137 Dealkylation of intermediate diselenonium dication 164 was suggested as the key step in the oxidative synthesis of 1,2,4-diselenazolidines 165 from eightmembered heterocycles 163. 198 Dealkylation is the main direction in the decomposition of mixed dications 166-168. Stability of these dications strongly depends on the nature of the chalcogen and substituents.…”

Intra- and intermolecular Se...X (X = Se, O) interactions in selenium-containing heterocycles: 3-benzoylimino-5-(morpholin-4-yl)-1,2,4-diselenazole

“…The bond lengths within the 1,2,4-diselenazole ring (Table 2) are comparable with those in 3-dimethylamino-5-phenyl-1,2,4diselenazolium tetrachloroniccolate (Rosenbaum et al, 1992), although the Se-Se bond in (I) is about 0.09 Å longer than that in the earlier report [2.293 (1) Å ]. There are no other structures containing an unfused 1,2,4-diselenazole ring recorded in the Cambridge Structural Database (CSD, Version 5.35 of 2013 plus two updates; Allen, 2002), although a structure incorporating a 1,2,4-diselenazolidine ring (all bonds in the ring are saturated; Takikawa et al, 1995Takikawa et al, , 2006 has an Se-Se distance of 2.331 (2) Å , while the Se-C and C-N bonds are about 0.15 and 0.07 Å longer, respectively, than those in the 1,2,4-diselenazoles.…”

Novel Thiofomylation of Primary and Secondary Amines Using N-Aryl-1,2,3,4,5,7-Pentathiazocanes

“…1-6 A dichloromethane solution of 2 was then treated with bromine-elemental sulfur or disulfur dichloride (S 2 Cl 2 ) at −78 • C, and in both cases, N-aryl-1,2,3,4,5,7-pentathiazocanes 1a-d were efficiently obtained through oxidative ring contraction of 1,5,3,7-dichalcogenadiazocines as shown in Scheme 2. 7,8 Conversion of 2 into 1 was assumed to proceed through a mechanism involving in situ formation of 1,5,3,7-dithiadiazabicyclo[3.3.0]octane-type mesocyclic dications 3 [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] followed by ring contraction and sulfur insertion. [27][28][29][30] Scheme 2 Preparation of N-aryl-1,2,3,4,5,7-pentathiazocanes 1.…”