Substituted calix (4) pyrroles and process for the synthesis of calix (4) pyrroles over molecular sieve catalysts
AssigneeCouncil of Scientific and Industrial Research
InventorsKondapuram Vijaya Raghavan, Shivanand Janardan Kulkarni, Motkuri Radha Kishan, Nagabandi Srinivas
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Abstract
The present invention relates to novel calix pyrroles and a process for synthesis of calix (4) pyrroles by reacting pyrrole with cyclic or acyclic ketones in dichloro methane (DCM) solvent over molecular sieve catalysts which provides an eco-friendly, more economical and selective heterogeneous method.
Claims29
A method of preparing a calix(4) pyrrole, said method comprising:
- (a) refluxing a pyrrole with an acyclic or cyclic ketone in the presence of a molecular sieve catalyst in an organic solvent at a temperature of about 100° C. for a period of between about 10 to about 72 hours;
- (b) cooling the reaction mixture of step (a) to room temperature;
- (c) filtering the solution of step (b) and washing the residue with an organic solvent to recover catalyst and to obtain a mother liquor;
- (d) evaporating to dryness the mother liquor of step (c) to obtain a solid;
- (e) washing the solid of step (d) with deionized water;
- (f) drying the washed solid of step (e) in air, followed by calcining at 373° K in air;
- and
- (g) purifying the calcined product of step (f) by column chromatography to obtain the calix (4) pyrrole.
A method for preparing a calix (4) pyrrole, said method comprising mixing a pyrrole with an acyclic or cyclic ketone over a molecular sieve solid acid catalyst, subjecting the mixture to microwave radiation for about 3 to about 10 minutes, and optionally, refluxing with a solvent to extract the calix (4) pyrrole.
Dependencies are inferred from the claim text.