Chemistry of cross-conjugated dienones

Reaction of 6-arylidene-2,2-dimethylcyclohexanones with phenylhydrazine. Molecular and crystal structures of 3-(4-halophenyl)-1-phenyl-4,5,6,7-tetrahydro-(2H)-indazoles

“…10,11 The conventional procedure for the synthesis of compounds I involves the nucleophilic addition of hydrazines or (thio)semicarbazides to 2 aryl idenecycloalkanones or 2,6 bis(arylidenecyclohexanones) followed by the cyclocondensation of the adduct. 12 In order to search for new fungicides, we continued our investigation of the cyclocondensation of 6 arylidene 2,2 dimethylcyclohexanones with 1,2 dinucleophiles by studying the reactions of these ketones with phenylhydr azine under different conditions.The reactions of phenylhydrazine with a series of 2,6 bis(arylidenecyclohexanones) 1 have been studied ear lier. 13 These reactions afforded hexahydroindazoles 2 as the major products along with dehydrogenated com pounds, viz., 1 phenyl substituted tetrahydroindazoles 3, as the minor products (Scheme 1).…”

“…10,11 The conventional procedure for the synthesis of compounds I involves the nucleophilic addition of hydrazines or (thio)semicarbazides to 2 aryl idenecycloalkanones or 2,6 bis(arylidenecyclohexanones) followed by the cyclocondensation of the adduct. 12 In order to search for new fungicides, we continued our investigation of the cyclocondensation of 6 arylidene 2,2 dimethylcyclohexanones with 1,2 dinucleophiles by studying the reactions of these ketones with phenylhydr azine under different conditions.…”

Lewis Acids as Mild and Effective Catalysts for the Synthesis of 3,5‐Bis[(hetero)arylidene]piperidin‐4‐ones

“…Therefore, if the starting substrates bear acid-or base-labile substituents such as CN, P(O)(OR) 2 , COOR, some heterocyclic moieties (e.g., furanyl) etc., the use of the above conditions would be unsuitable. Thus, several improvements have been achieved in the synthesis of bis(heteroarylidene)cycloalkanones by application of KF-supported reagents under microwave or ultrasonic irradiation [3], Pd/C-mediated synthesis [4], and Lewis acid catalysis including Me 3 SiI (TMSI) [5], Yb(OTf) 3 [6], LiClO 4 in the presence of amines [7], and MgBr 2 · Et 2 O/ MeOH/Et 3 N [8], as well as SmI 3 [9] and FeCl 3 [10] in ionic liquids.…”

“…Introduction. -In the last decade, derivatives of bis(heteroarylidene)cycloalkanones and the related bis(heteroarylidene)piperidin-4-ones attracted remarkable interest due to their high and diverse biological activities such as antiviral, antitumor, radical-scavenging, and antimutagen properties [1], as well as their application as ligands for the construction of coordination polymers [2]. Regarding the bioactivities, the conjugated 1,5-di(hetero)aryl-3-oxopenta-1,4-dienyl pharmacophore group in these compounds is assumed to interact with cellular constituents, since the nature of the (hetero)aryl substituents and those attached to the heterocyclic N-atom in the related piperidinone derivatives affects their potency.…”

Novel Linear Bis-Crown Receptors with Cross-Conjugated and Conjugated Central Cores

“…Cross-conjugated dienones -derivatives of cyclic ketones [12] -attract the attention of researchers due to their rich synthetic chemistry, primarily for the production of heterocycles, [13][14][15] and wide opportunities for application, especially in biology, agriculture and the creation of new materials. [16][17][18][19][20][21][22] Recently, cross-conjugated dienones with pyridine substituents have been used as ligands to produce discrete and polymeric coordination compounds.…”