Sulfamic acid: a novel and efficient catalyst for the synthesis of aryl-14H-dibenzo[a.j]xanthenes under conventional heating and microwave irradiation

A DABCO Derived Ionic Liquid Based on Tetrafluoroborate Anion: Preparation, Characterization and Evaluation of its Catalytic Activity in the Synthesis of 14-Aryl-14H-dibenzo[a, j]xanthenes

“…No product was obtained in the absence of the catalyst (entry 1) and only a trace amount of the product was obtained in the presence of the catalyst at room temperature (entry 5) indicating that the catalyst and temperature are necessary for the reaction. Increasing the amount of the catalyst and reaction temperature up to 3 mol % (based on 4-chlorobenzaldehyde) and 100 °C, respectively, increased the yield of the product 3e, whereas further increase in both catalyst amount and temperature was found to have an inhibitory effect on the formation of the product (entries [10][11][12][13][14].…”

“…The IR spectra were obtained using a Tensor 27 Bruker spectrophotometer as KBr disks. The 1 H NMR (500 MHz) and 13 C NMR (125 MHz) spectra were recorded with a Bruker DRX500 spectrometer. Mass spectra were also obtained using a FINNIGAN-MAT 8430 mass spectrometer operating at an ionization potential of 70 eV.…”

Ultrasound assisted synthesis of tetrahydrobenzo[c]xanthene-11-ones using CAN as catalyst

“…Different catalysts such as sulfamic acid [10], p-TSA [11], selectfluor TM [12], iodine [13], silica sulfuric acid [14], Yb(OTf) 3 [15] and ionic liquids [16] find application in the synthesis of benzo [a]xanthenes. The existing methods have not been conceded for the synthesis of tetrahydrobenzo [c]xanthene-11-ones from a-naphthol (Scheme 1), this is because, the electron density at the b-position of the a-naphthol is not sufficient for the formation of the corresponding ortho-Quinone Methides (o-QMs, Scheme 2) under these conditions.…”

Calcium Chloride/HCl An Efficient Co-catalytic System For Synthesis Xanthene Under Microwave Condition

“…To suppress these drawbacks, the search of a new and efficient catalyst with high catalytic activity, short reaction time, recyclability, and simple reaction condition for the preparation of xanthenes under neutral mild and practical conditions is of key interest. An improvement in reaction procedure is made by reacting 2-naphthol with alkyl/aryl aldehydes employing various catalysts such as Bronsted acids, [25][26][27] solid supported reagent, [28,29] Metal salt, [30,31] Metal triflate, [32] I2 , [33] Phosphosulfonic acid, [34] trichloroisocyanuric acid, (TCCA), [35] Vanadatesulfuric acid, [36] HBF4-SiO2. [37] However, some these methods are suffer from one or more shortcomings like expensive and toxic catalyst, acidic condition, long reaction time, low yield, preparation of catalyst require in some cases, use of heavy and toxic metal.…”