Chlorotrimethylsilane Mediated Synthesis of 5-(2-Hydroxybenzoyl)pyrimidines from 3-Formylchromones

Reactivity of some 3‐substituted‐6,8‐dimethylchromones toward some nucleophilic reagents

“…Also, treatment of carboxaldehyde 1 with 2‐aminobenzimidazole yielded pyrimido[1,2‐ a ] benzimidazole derivative 7 (Scheme 1). 28 Compound 7 was confirmed from the mass spectrum and showed the molecular ion peak, as the base peak, at m/z 317. Its 1 H NMR spectrum revealed two specific singlet signals attributed to H‐4 pyrimidine and H‐6 pyrimidine at δ 7.52 and 7.63, respectively.…”

“…Reaction of 6,8‐dimethylchromone‐3‐carboxaldehyde ( 1 ) with 3‐amino‐1,2,4‐triazole, in boiling ethanol, afforded triazolo[1,5‐ a ]pyrimidine derivative 6 (Scheme 1). 28 The reaction proceeds through condensation of the amino group with the aldehyde group, intermediate A , followed by nucleophilic attack at C‐2 position with γ‐pyrone ring opening. The 1 H NMR spectrum of compound 6 consists of seven singlet signals, in addition to D 2 O exchangeable signal attributed to the OH proton at δ 11.78.…”

Heterocyclizations of β-alkoxy, β-diaminoalkyl, and related β-functionalized enones (enals) with NCN-binucleophiles

“…The scope of this type of heterocyclization was extended to derivatives substituted by benzene ring [179], the corresponding ketochromones [180], di-and trifluoromethyl ketones [181,182], glyoxylate [183], which all underwent recyclization with NCN binucleophiles [182]. Aside from the common reaction conditions for the heterocyclization with NCN binucleophiles, which typically relied on using alkali or alcoholates (rarely, K2CO3 or Et3N) as bases, significant synthetic advances were achieved by using TMSCl in DMF, which was disclosed in a series of papers by Volochnyuk, Ryabukhin, and co-workers [184][185][186][187][188]. Recyclization of carbonyl-substituted 4Н-chromenes and 1Н-benzo[f]chromenes by the treatment with amidines and guanidines has also been reported [189].…”

Facile Synthesis of N‐(Benzyl‐1H‐1,2,3‐Triazol‐5‐yl) Methyl)‐4‐(6‐Methoxybenzo [d] Thiazol‐2‐yl)‐2‐Nitrobenzamides via Click Chemistry

“…Benzothiazole scaffold derivatives consist of fused bicyclic ring systems. Benzothiazoles are an important class of potential organic molecules in medicinal chemistry because of their extensive range of activity such as neuron protective , anti‐convulsive , anti‐glutamate , anti‐malarial , anthelmintic , anti‐tubercular , analgesic, anti‐inflammatory , antimicrobial , and anti‐cancer effect . In this context, promising biological profile molecules that are synthetically accessible have attracted the attention of medicinal organic chemists.…”