Efficient Synthesis of 2‐Arylamino‐2‐imidazolines and 2‐Ami‐ nobenzimidazoles with Aminoiminomethanesulfonic Acid Derivatives

Abstract

A highly efficient synthesis of 2-arylamino-2-imidazolines and 2-aminobenzimidazoles from aminoiminomethanesulfonic acid derivatives is described. The method is simple and practical, generating imidazoline and benzimidazoline derivatives in excellent isolated yields.

Recent Advances in the Synthesis of Imidazolines (2009–2020)

“…In 2011, Zhang et al reported another synthesis of 2-imidazolines from the reaction of ethylenediamine (34) with aromatic nitriles (33) (Scheme 8). [32] This synthetic approach was assisted by reusable cupric indole-3-acetate (Cu(II)-(IAA) 2 ) catalyst in the solvent-free condition under either reflux or microwave irradiation.…”

“…Mohanazadeh et al demonstrated the synthesis of 2-arylamino-2-imidazolines (46) from a reaction between amino(phenylimino)methanesulfonic acid derivatives (44) and ethylenediamine (45) under mild reaction conditions (Scheme 12). [34] The reaction used 2-propanol or water as reaction medium, where 2propanol affords better yields (80-93%) of the imidazoline products (yields in water 54-77%). Under optimized conditions, only halogen-substituted (p-ClPh, p-BrPh, 2,6-Cl 2 Ph) aromatic moieties were incorporated in the acid derivates.…”

Polymer-Supported Stereoselective Synthesis of Benzimidazolinopiperazinones

“…The aromatic part of 1,2-dihydrobenzo[4,5]imidazo[1,2- a ]pyrazin-3(4 H )-ones II , benzimidazoles, were synthesized several times, in solution − and on solid phase. − Benzimidazole derivatives can serve as angiotensin II receptor antagonists, as inhibitors of trypsin-like serine protease (factor Xa), and as antibacterial agents . The synthesis of benzimidazolines and their closely related compounds, 2-oxo/thioderivatives and spiro-benzimidazolines, has also been described. ,− …”

Lessons Learned from the Explosion that Occurred during the Synthesis of Diaminomethanesulfonic Acid: Discussion and Preventative Strategies

“…The syntheses of diaminomethanesulfonic acid under other conditions based on this method were reported in some of the literature (Scheme A). − In addition to this route, diaminomethanesulfonic acid was also synthesized from thiourea with several different conditions (Scheme B). − …”

“… a (a) AcOOH, AcOH, −20 °C, ambient temperature, 2 h; , (b) H 2 O 2 , 20 °C, 2 h; (c) AcOOH, MeOH, 24 h, ambient temperature; (d) Na 2 MoO 4 , H 2 O 2 , NaCl, H 2 O, 0–30 °C; (e) H 2 SO 4 , H 2 O 2 , Ac 2 O, MeOH, H 2 O, 20 °C, 48 h; (f) HCl, H 2 SeO 3 …”