201023-86-1Relevant articles and documents
An expeditious and highly efficient synthesis of substituted pyrroles using a low melting deep eutectic mixture
Alvi, Shakeel,Ali, Rashid
, p. 9732 - 9745 (2021/12/01)
An expeditious green method for the synthesis of diverse valued substituted pyrroles through a Paal-Knorr condensation reaction, using a variety of amines and 2,5-hexanedione/2,5-dimethoxytetrahydrofuran in the presence of a low melting mixture ofN,N’-dimethylurea andL-(+)-tartaric acid (which acts as a dual catalyst/solvent system), has fruitfully been revealed. Herein, we have disclosed the applicability of this simple yet effective strategy for the generation of mono- and dipyrroles in good to excellent yields. Moreover,C3-symmetric tripyrrolo-truxene derivatives have also been assembled by means of cyclotrimerization, Paal-Knorr and Clauson-Kaas reactions as crucial steps. Interestingly, the melting mixture was recovered and reused with only a gradual decrease in the catalytic activity (over four cycles) without any significant drop in the yield of the product. This particular methodology is simple, rapid, environmental friendly, and high yielding for the generation of a variety of pyrroles. To the best of our knowledge, the present work reveals the fastest greener method reported up to this date for the construction of substituted pyrroles by utilizing the Paal-Knorr synthetic protocol, achieving impressive yields under operationally simple reaction conditions without involving any precarious/dangerous catalysts or unsafe volatile organic solvents.
Greener Paal-Knorr Pyrrole Synthesis by Mechanical Activation
Akelis, Liudvikas,Rousseau, Jolanta,Juskenas, Robertas,Dodonova, Jelena,Rousseau, Cyril,Menuel, Stphane,Prevost, Dominique,Tumkeviius, Sigitas,Monflier, Eric,Hapiot, Frdric
, p. 31 - 35 (2016/01/20)
A straightforward and solventless synthesis of pyrroles was developed by using mechanochemical activation and a biosourced organic acid as the catalyst. Relative to traditional Paal-Knorr methodologies, various N-substituted pyrroles were obtained in very short reaction times. By reaction with unreactive diketones, desymmetrized aliphatic and aromatic compounds were also synthesized.
Paal-knorr pyrrole synthesis in water
Akbaslar, Dilek,Demirkol, Onur,Giray, Sultan
supporting information, p. 1323 - 1332 (2014/04/17)
Water was a suitable medium for Paal-Knorr pyrrole cyclocondensation. Hexa-2,5-dione was reacted with several aliphatic and aromatic primary amines, affording N-substituted 2,5-dimethyl pyrrole derivatives in good to excellent yields. An efficient, green method using water either as environmentally friendly solvent or catalyst was presented.
