Advances in Imidazole Chemistry

Five‐Membered Heterocycles: 1,3‐Azoles

“…Similarly, thiazoles are attacked in acidic media by methyl and propyl radicals to give 2-substituted derivatives in moderate yields, with smaller amounts of 5-substitution. Similar reactions occur with acyl radicals, for example with the CONH 2 radical from formamide [305].…”

Six‐Membered Heterocycles: Triazines, Tetrazines and Other Polyaza Systems

“…Direct halogenation of the parent 1,2,4-triazine (2) has not been reported, and any electron-donating substituents present will not necessarily counteract the inherent resistance of the ring to electrophilic substitution [319,320]. An oxo substituent at the 5-position is sufficiently activating to permit the 6-bromination of some 1,2,4-triazin-5-ones and -3,5-diones [183].…”

“…Formation of triazine N-oxides by reaction of amidooxime with ethyl orthoacetate gives poor yields [661]. The reactivity of 1,3,5-triazine (3) has been thoroughly reviewed [26,39,41,474,662] and the chemistry of melamine, cyanuric acid and cyanuric halides has also been reviewed [34,35,120,663]. In general, many of the reactions of 1,3,5-triazines reflect the chemistry of the ring substituents.…”

“…The reactions are probably not electrophilic [35,39,43,320,674]. Treatment of 1,3,5-triazine with chlorine or bromine at room temperature gives rise to perhalides [43].…”

Nematicidal, larvicidal and antimicrobial activities of some new mannich base imidazole derivatives

“…Naturally occurring and synthetic imidazole derivatives are an important class of heterocycles that are known to exhibit various biological activities [1]. The imidazole nucleus is a major component in a variety of drugs, including angiotensin II receptor antagonists, anti-inflammatory agents, protein kinase inhibitors, and fungicides [2].…”