Facile Microwave-Assisted Synthesis of Cyclic Amidinium Salts

Abstract

The cyclization of N,N'-dialkyl or diaryl ethane-1,2-diamines or propane-1,3-diamines with inorganic ammonium salts and orthoesters proceeds briskly under microwave irradiation to afford the corresponding imidazolinium or tetrahydropyrimidinium salts. The transformation is highly versatile and tolerates a wide range of substituents and counterions. It could be scaled from 1 to 50 mmol without any difficulty. Because the workup is equally rapid and straightforward, this experimental procedure provides fast and convenient access to an important class of heterocyclic compounds that have found numerous applications as N-heterocyclic carbene precursors, organocatalysts, and ionic liquids.

Recent N-Atom Containing Compounds from Indo-Pacific Invertebrates

“…To the best of our knowledge, the only naturally reported tetrahydropyrimidinium ring, as in haliclorensin B, is the pyrrole-derived alkaloid N -methylmanzacidin C isolated from the sponge Axinella bre V istyla [52]. Indeed, the tetrahydropyrimidinium ring by itself is known synthetically [53,54]. Haliclorensin C joins two other marine, naturally occurring azacycloalkanes, i.e.…”

Microwave‐Assisted Synthesis of 1,3‐Dimesitylimidazolinium Chloride

“…In these experiments, recourse to an amine free base together with an inorganic ammonium salt as starting materials provided an easy way to vary the nature of the counterion (Table 2). 10 Indeed, bulky polyatomic anions such as BF 4 -, PF 6 -, TfO -, or Tf 2 Ncould be introduced directly using readily available ammonium salts, thereby eliminating the need for subsequent ion exchange.…”

“…Microwave-assisted synthesis of 1,3-diarylimidazolinium chlorides. Microwave-assisted synthesis of cyclic amidinium salts 10. Somenath Chowdhury grew up in Majirdanga, India.He obtained his M.Sc.…”

Synthesis and investigation of new cyclic haloamidinium salts

“…NMR spectra were recorded at 30°C on a Bruker Avance 500 ( 1 H, 500 MHz; 13 1a [43], 1b [29], 1c [44], 13 [43], and 15 [45] were synthesized according to literature procedures, and spectral data were consistent.…”