This review describes the formation of six-membered heterocyclic compounds and their fused analogues under microwave activation using modern organic transformations including cyclocondensation, cycloaddition, multicomponents and other modular reactions. The review is divided according to the main heterocycle types in order of increasing complexity, starting with heterocyclic systems containing ...

The use of methanesulfonic acid as solvent and catalyst in the cyclocondensation of 1,2-dialkoxybenzenes with 3-methylbut-2-enoyl chloride to afford indanones 3, thus allowing the prepara­ tion of indenes 4 with improved overall yields, is reported. Additionally, structure of dimeric compound 7 a, formed in high yield by thermal treatment of 4a has been determined by combination of spectroscopi...

A general and efficient phosphorous acid-catalyzed cyclocondensation of β-ketoesters with o-aminobenzamides via selective C-C bond cleavage leading to quinazolinones is developed. This reaction proceeds smoothly under metal- and oxidant-free conditions, giving both 2-alkyl- and 2-aryl-substituted quinazolinones in excellent yields. This strategy can also be applied to the synthesis of other N-h...

A palladium-catalyzed intermolecular cascade (4+3) cyclocondensation of salicylaldehydes and vinylcyclopropanes is reported. key feature the reaction use a phosphonate group as an acceptor moiety on cyclopropane, exploiting its propensity to undergo olefination with aldehydes. Subsequent O-allylation enabled formation range substituted benzoxepinsWith novel chiral ligand, products were obtained...

LiNH2BH3-promoted reductive opening of 8-substituted phenylglycinol-derived oxazolopiperidone lactams leads to enantiopure 4-substituted-5-aminopentanols, which are used as starting building blocks in the synthesis of the Haliclona alkaloids haliclorensin C, haliclorensin, and halitulin (formal). The starting lactams are easily accessible by a cyclocondensation reaction of (R)-phenylglycinol wi...

In the present work, bakers yeast catalyzed efficient synthesis of 2-amino-2-chromenes in methanol is presented. Here ultrasonication has dual role i.e. as a source energy for reaction and tool disruption cells. The cyclocondensation been essentially carried under neutral conditions, thus reducing possibility unwanted side reactions.

microwave-assisted three component cyclocondensation reactions of aldehydes, amides and dienophiles in the presence of acetic anhydride and para-toluenesulfonic acid as a catalyst to afford the highly substituted cyclohexene derivatives, in relatively good yields after several minutes are reported.

A synthesis of functionalized fused pyrimidine derivatives from the respective ortho-nitroaromatic carboximes is described. Commercially available nitroarenes were transformed according to a known manner into the ortho-nitroaromatic carboximes. Selective catalytic reduction of the nitro group in these compounds followed by condensation of the amines formed with various orthoesters, resulted in ...

ABSTRACT A series of novel 5-substituted 2-[2-(pyridyl)ethenyl]-1,3,4-oxadiazoles were efficiently synthesized by cyclocondensation of the appropriate 3-(pyridyl)acrylohydrazides with triethyl orthoesters in the presence of glacial acetic acid. The products were identified by means of spectroscopic methods and their pKA ionization constants were determined. The influence of substituents on the ...