A Facile Solvent Free Claisen-Schmidt Reaction: Synthesis of α,α′-bis-(Substituted-benzylidene)cycloalkanones and α,α′-bis-(Substituted-alkylidene)cycloalkanones

Abstract

Solvent-free Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes (aryl aldehydes) using solid NaOH (20 mol%) and applying a grinding technique were studied. Quantitative yields (96–98%) of α,α'-bis-(substituted-benzylidene)cycloalkanones were obtained. Aliphatic aldehydes also provided α,α'-bis-(substituted-alkylidene)cycloalkanones in very good yields with minor amounts of α-(substituted-alkylidene)cycloalkanones. The catalytic performance of solid NaOH was examined. The molar ratio of NaOH was optimized. The catalytic effect of solid NaOH was also evaluated by comparing it with KOH, NaOAc, and NH4OAc and it turns out that 20 mol% of solid NaOH was good enough to catalyze the Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes. Additionally, the regioselectivity of the Claisen-Schmidt reaction of acetone with benzaldehyde was examined. Using the same method, we could synthesize the corresponding bis-benzylidene- and mono-benzylideneacetone separately in 98% and 96% yields, respectively.

Synthesis, Characterization, and Biological Evaluation of Some Novel Quinoxaline Derivatives as Antiviral Agents

“…Thermal cyclocondensation of oxyacetic acid derivative with thiocarbodihydrazide was carried out on neat . Also, successful cyclocondensation through the utility of NaOH plates was reported . Based on these findings, the ethyl dihydroquinoxalinyl acetate 1a was ground with semicarazide HCl and sodium hydroxide plates, at room temperature.…”

“…[(2-oxo-1,2,3,4-tetrahydroquinoxalin-3-yl)hydrazine-2-yl]but-2-enedioate(13), diethyl-2-[(6-methyl-2-oxo-1,2,3,4-tetrahydroquinoxalin-3-yl)acetohydrazin-2yl]but-2-enedioate(15) Compounds 13 and 15 were prepared by mixing hydrazide derivative 12 or acetohydrazides 14b with diethylacetylenedicarboxylate (1 mmol of each) in acetic acid reflux for 1 h. TheArch. Pharm.…”

Green Synthesis Senyawa Imina dari Vanillin and Anilina dengan Katalis Alami Air Jeruk Nipis (Citrus aurantifolia)

“…Adapun beberapa kelebihan green synthesis adalah ekonomis, mudah, ramah lingkungan dan efisien. Sintesis senyawa imina dapat dilakukan dengan beberapa metode yaitu melalui metode penggerusan (Rahman, Ali, Jahng, & Kadi, 2012), penggunaan pelarut air (Naqvi, Shahnawaaz, Rao, Seth & Sharma 2009), dan penggunaan katalis asam alami (Patil, Jadhav, & Deshmukh, 2011a;Patil, Jadhav, & Patil, 2012). Sintesis beberapa senyawa imina dilakukan dengan bantuan katalis air lemon dan menghasilkan produk imina sebesar 72-100% (Patil et al, 2011a;Patil et al, 2012).…”

Economically Viable and Efficient Catalysts for Esterification and Cross Aldol Condensation Reactions under Mild Conditions

“…An another important chemical product, α,α’‐bis(arylidene)‐cycloalkanone derivatives, have also attracted much attention because of their uses as precursors for the synthesis of jet fuel high‐density cycloalkane, pyrimidine derivatives, interesting biological activities such as cholesterol‐lowering, quinine reductase inducer, and antiparasitic properties, and application as new organic materials in nonlinear optical systems, units of liquid‐crystalline polymers, and cytotoxic analogs . The crossed aldol condensation reaction between cycloalkanones and aryl aldehydes, also referred to as Claisen Schmidt reaction has been established as the best synthetic route toward α,α’‐bis(arylidene)cycloalkanones . Most of the catalysts such as [Cp 2 ZrH 2 ], [Cp 2 TiPh 2 ], bis ( p ‐methoxy‐phenyl)telluroxide (BMPTO), [RuCl 3 ], [SmI 3 ], TiCl 3 (CF 3 SO 3 ), La 3+ ‐immobilized organic solid, [KF‐Al 2 O 3 ], [Mg(HSO 4 ) 2 ], [FeCl 3 ], [BF 3 ⋅OEt 2 ], [InCl 3 ], [TMSCl/NaI], [TMSCl/Pd−C], [SOCl 2 ], [Yb(OTf) 3 ], [K 2 CO 3 /PEG‐400] molecular I 2 , [Cu(OTf) 2 ], silica chloride, silica‐supported phosphorus pentoxide (P 2 O 5 /SiO 2 ) or silicaphosphinoxide (silphox, [POCl 3‐n (SiO 2 ) n ]) as heterogeneous reagents, 1‐methyl‐3(2‐(sulfooxy)ethyl)‐1 H ‐imidazol‐3‐iumchloride, and Et 3 N in the presence of [LiClO 4 ] used for this transformation are expensive, toxic, and require harsh reaction conditions.…”