2,8-Dithia-dibenzo[e,h]azulenes and Their 8-Oxa Analogs. Synthesis and Anti-inflammatory Activity

Novel tetracyclic imidazole derivatives: Synthesis, dynamic NMR study, and anti‐inflammatory evaluation

“…From 7i and 7j under the same conditions are obtained 8i and 8j . Both sets of hydroxymethyl imidazole derivatives are converted to dialkylaminoalkyl ethers 9a , 9b , 9c , 9d , 9e , 9f , 9g , 9h , 9i , 9j , 9k , 9l , 9m , 9n , 9o , 9p , 9r , 9s , 9t , 9v on treatment with ω‐chloroalkyl‐dimethylamines under phase transfer conditions in the presence of benzyltriethylammonium chloride (BTEAC), Scheme [4, 29].…”

“…In the frame of our project aimed toward synthesis, structure determination of tetracyclic imidazoles, and screening of their activity on the selected biological targets, we entered the study of a large series of dibenzo‐oxepin‐ and dibenzo‐thiepin imidazole derivatives. In our previous articles we have reported on the synthesis, properties, and preliminary biological results of oxa‐, aza‐, and thia‐dibenzoazulenes, characterized by the annulated furane I [2], pyrrole II , III [3], and thiophene IV , V [4] ring (Fig. 1).…”

Dibenzo[b,f]oxepin‐10(11H)‐one and dibenzo[b,f]thiepin‐10(11H)‐one as useful synthons in the synthesis of various dibenzo[e,h]azulenes

“…Starting ketones 1a , 1b , 1c are oxidized with selenium dioxide to corresponding 1,2‐diketones 4a , 4b , 4c , which are condensed with dimethyl 2,2′‐thiodiacetate in the presence of potassium tert ‐butoxide in tert ‐butanol. This method, known as Hinsberg thiophene synthesis [24], provides tetracyclic, 1,3‐disubstituted 2‐thia‐dibenzo[ e , h ]azulenes 5a , 5b , 5c , 5d [15].…”

“…When symmetrical α‐diketones 4a , 4b were submitted to reaction, half‐esters of thiophene dicarboxylic acids 5a , 5b were obtained in good yields [15]. However, the use of unsymmetrically substituted α‐diketone 1c is complicated by the formation of approximately 50:50 isomeric mixture of 5c and 5d as a result of chemical equivalence of the two carbonyl groups (Scheme 3) [15]. α,α′‐Dicarboxyl‐substituted thiophenes 5 are promising platform for further derivatization toward anticipated target molecules [27].…”

“…Broad biological activity prompted the use of dibenzo[ b,f ]oxepines and dibenzo[ b,f ]thiepines as key building blocks in synthesis of various polycyclic compounds [10–12]. Recently, synthesis and biological activity of several novel heterocyclic dibenzo[ e,h ]azulene scaffolds have been reported [13–16]. Following literature findings that several different heterocycles can be synthesized from a single substrate [17, 18], an extensive survey of the synthesis of various heterocyclic dibenzo[ e,h ]azulenes resulted in efficient and all‐purpose strategy for the synthesis of dibenzoxepino[5,6]‐ and dibenzothiepino[5,6]‐fused five‐membered heterocycles originating from the common precursors, dibenzo[ b,f ]oxepine‐10(11 H )‐one and its sulfur analogue.…”