Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• variety of small molecules and to bind strongly to metal centers, thereby affording very robust catalysts [9][10][11][12]. Another category of stable carbenes that has emerged in the new millennium is made of mesoionic compounds, for which no reasonable canonical resonance form can be drawn in the absence

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• its N-methyl derivatives by the t-BuOH/HClO4 system followed by the treatment of the tetrazolium salts by alkali. The mesoionic compounds have been found to show a higher reactivity of the exocyclic N atom in comparison with 5-aminotetrazoles. The compounds reacted with 1,2-dibromoethane and 5

• : aminotetrazoles; DFT; mesoionic compounds; UV–vis spectra; X-ray analysis; Introduction 5-Aminotetrazoles are one of the most available and valuable tetrazole derivatives. So, due to the thermal stability and high nitrogen content the parent 5-aminotetrazole (1, Figure 1) is of practical interest as a gas

• tetrazole-5-aminides were carried out as a part of studies of mesoionic compounds [22][23][24]. Earlier, we reported the facile preparation of 1,3-di-tert-butyltetrazolium-5-aminide [25], which was later used for the synthesis of the first tetrazolium halocuprate [26] and also shown to react with bromine

Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

• Jan Szabo,
• Julian Greiner and
• Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

• hydrogenation of an N-benzyl derivative. Crystal structure analyses of a 4-benzylamino-1,2,4-triazolium-3-hydrazinide and of two derived 1,2,4-triazolium salts are presented. Keywords: guanidines; mesoionic compounds; triaminoguanidinium salts; 1,2,4-triazolium-3-aminides; Introduction Easily accessible by

• -3-aminide, depending on the reaction conditions. Because of the long-standing interest in the bond structure of mesoionic compounds, we have also conducted some structural and spectroscopic studies of the new 1,2,4-triazolium-3-aminides and the 3-amino-1,2,4-triazolium salts derived thereof [33

• . Both the use of a weak base and a mild reaction temperature favor the formation of 6 at the expense of competitively formed mesoionic compounds 7. This can be seen for the acylation of 4 with benzoyl chloride, where an elevated temperature was required for a sufficiently fast conversion and a mixture

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

• Ming Liu,
• Jan C. Namyslo,
• Martin Nieger,
• Mika Polamo and
• Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

• been prepared from mesoionic compounds (Figure 1). The carbenes 3 [31] and 4 [32][33] originate from a conjugated ylide and a cross-conjugated mesomeric betaine, respectively. A review elucidates the interconversions of mesomeric betaines to different types of N-heterocyclic carbenes (NHC, aNHC, rNHC

Synthesis of 3-(phenylazo)-1,2,4-triazoles by a nucleophilic reaction of primary amines with 5-chloro- 2,3-diphenyltetrazolium salt via mesoionic 2,3-diphenyltetrazolium- 5-aminides

• Shuki Araki,
• Satoshi Hirose,
• Yoshikazu Konishi,
• Masatoshi Nogura and
• Tsunehisa Hirashita

Beilstein J. Org. Chem. 2009, 5, No. 8, doi:10.3762/bjoc.5.8

• mechanism is proposed for the formation of the triazoles via Type B mesoionic tetrazolium-5-aminides. Keywords: formazan; mesoionic compounds; nucleophilic substitution; tetrazolium; 1,2,4-triazole; Introduction Mesoionic compounds can be classified into two families, type A and type B mesoions, according

• to their electronic arrangements [1][2][3][4][5]. Type B mesoionic compounds are less common compared with type A mesoions. The 5-chloro-1,3-diphenyltetrazolium salt (1) has been proved to be a versatile precursor to several type A 1,3-diphenyltetrazolium mesoionic compounds, because the chlorine