40651-95-4Relevant articles and documents
Facile Access to 1,4-Disubstituted Pyrrolo[1,2- a ]pyrazines from α-Aminoacetonitriles
Basha, Mushkin,Belema, Makonen,Dhar, T. G. Murali,Gupta, Anuradha,Gupta, Arun Kumar,Indasi, Gopi Kumar,Karmakar, Ananta,Mathur, Arvind,Meanwell, Nicholas A.,Ramalingam, Sridharan,Rampulla, Richard
supporting information, p. 441 - 449 (2020/01/23)
An efficient and practical synthetic protocol for the synthesis of 1,4-disubstituted pyrrolo[1,2- a ]pyrazine derivatives is described that originates from α-substituted pyrroloacetonitriles which, in turn, are readily available from aryl and alkyl aldehydes. The α-pyrroloacetonitriles were subjected to a Friedel-Crafts acylation with methyl chlorooxoacetate followed by reduction of the nitrile group under Pd-catalyzed hydrogenation conditions and finally aromatization with DDQ leading to the desired pyrrolo[1,2- a ]pyrazine derivatives. This method was generalized and successfully applied to various aryl, heteroaryl, and alkyl substrates. The developed protocol provides direct and convenient access to 1,4-disubstituted ring systems in moderate to good overall yields (51-68percent) without the need for purification of the intermediates. Further functionalization via the stepwise halogenation (bromination, iodination) and nitration was also demonstrated. In addition, the potential of the ester functionality for elaboration was demonstrated by manipulating into heterocyclic ring systems, exemplified by conversion into benzoxazole derivatives.
Pyrroles and indolizidines from deprotonated α-(alkylideneamino) nitriles
Schaefer, Ines,Opatz, Till
experimental part, p. 1691 - 1704 (2011/07/29)
Their ready availability from simple starting materials in only two synthetic steps and their versatility as building blocks for the construction of highly substituted amines and N-heterocycles renders α-(alkylideneamino) nitriles useful synthetic intermediates. Herein, short syntheses of tri- and tetrasubstituted pyrroles including the northern half of the HMG-CoA reductase inhibitor atorvastatin as well as an access to 3-substituted indolizidines will be described. Georg Thieme Verlag Stuttgart - New York.