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Abstract

Porosity and acidity of molecular sieve Al-MCM-41 (ca. 30 A pore diameter) plays a crucial role in the synthesis of novel calix(4)pyrroles; for the first time, Al-MCM-41 has been used as a solid acid catalyst to produce a number of calix(4)pyrroles with good selectivity ad yields where zeolite HY (ca. 7.6 A pore diameter) yields mainly the linear chain dimer and no cyclic products.

Use of Graphite Oxide and Graphene Oxide as Catalysts in the Synthesis of Dipyrromethane and Calix[4]pyrrole

“…The reaction of 1 with cyclohexanone ( 2b ) gave the corresponding dipyrromethane 3b in 70% yield. An analogous condensation of pyrrole and 2b in dichloromethane in the presence of the solid acid zeolite HY gave dipyrromethane 3b in 63% yield, along with other products, whereas the same reaction in the presence of HZSM in dichloromethane gave dipyrromethane 3b and calix[4]pyrrole 4b in 53 and 11% yield, respectively [52]. The reaction of 1 with 2a in the presence of Al-MCM-41 zeolite gave 3a and 4a in 12 and 70% yield, respectively [52].…”

“…An analogous condensation of pyrrole and 2b in dichloromethane in the presence of the solid acid zeolite HY gave dipyrromethane 3b in 63% yield, along with other products, whereas the same reaction in the presence of HZSM in dichloromethane gave dipyrromethane 3b and calix[4]pyrrole 4b in 53 and 11% yield, respectively [52]. The reaction of 1 with 2a in the presence of Al-MCM-41 zeolite gave 3a and 4a in 12 and 70% yield, respectively [52]. The reaction of the above in the presence of Amberlyst TM -15 gave 4a and N-confused calix[4]pyrrole in 83 and 14% yield, respectively [55].…”

“…This was also confirmed by reaction of 3a with 2b with the formation of 5 in 17% yield. (Table 1) [52]. The reaction of 1 and 2a was performed in other polar solvents and the results are reported in Table 1.…”

“…They are synthesized by condensation of pyrroles with dialkylketones in the presence of aqueous acids [48,49], Lewis acids [50,51] and solid acids including zeolites [52], molecular sieves [53,54] and Amberlyst-15 [55] under different reaction conditions. Although various solid acids have been used in the synthesis of different calix[4]pyrroles, to the best of our knowledge graphite oxide and graphene oxides have not been used for this purpose.…”

A General Strategy for the Rational Design of Size‐Selective Mesoporous Catalysts

“…[10] Kishna et al demonstrated the shape-selective synthesis of calix [4]pyrrols over a Lewis acidic MCM-41 catalyst. [11] The tailoring of mesoporous materials for size-selective adsorption and drug delivery has found widespread interest. [12] Some mesoporous materials (e.g.…”