Zur Synthese von 3-Amino-pyrrolen durch Thorpe-Ziegler-Cyclisierung

Abstract

On the Synthesis of 3‐Amino‐pyrroles by Thorpe‐Ziegler‐Cyclization N‐Aryl and alkylaminomethylene cyanacetic acid derivatives 1 react with α‐halogencarbonyl compounds 2 in the presence of potassium carbonate/sodium ethoxide to yield the substituted 3‐amino‐pyrroles 6. Using the same principle of cyclization pyrrole derivatives 6 can also be obtained by reaction of β‐chloro‐ and β‐alkoxymethylenemalononitriles 4 with β‐aminocarbonyl compounds 5. From the malononitrile derivatives 1 containing the methylthio group in the β‐position, and α‐halogen ketones 7, the 2‐dicyanomethylene oxazolines 8 arise which undergo alkoholysis by treatment with sodium alkoxide to form the 3‐amino‐5‐alkoxy‐pyrrole derivatives 9.

An efficient synthesis of 2,3,6,7-tetrasubstituted 4,6-dihydro-4-oxo-3H-pyrrolo[3,4-d]pyrimidin-7-carbonitrile derivatives

“…The ethyl 4-amino-5-cyano-1-phenyl-1H-pyrrole-3-carboxylate 2, easily prepared by reaction of compound 1 28 with bromoacetonitrile under basic conditions, was converted into iminophosphorane 3 via reaction with triphenylphosphine, hexachloroethane and triethylamine in dry acetonitrile in good yield (Scheme 1).…”

Synthesis of New Tacrine Analogues from 4‐Amino‐1H‐pyrrole‐3‐carbonitrile

“…The preparation of 2-substituted 3-amino-1H-pyrrole-4-carbonitriles 3 by using ahalo ketones (or a-halo nitriles or esters) in anhydrous DMF in the presence of K 2 CO 3 as the base has been well described in the literature [13]. Here, we report the preparation of compounds 3 by a modification of the method described previously using Et 3 N (TEA) as the base [14].…”

“…-In continuation of our interest in the chemistry of b,benamino nitriles, the results aimed at exploring the potential utility of 3-anilino-2-cyanoacrylonitrile in the synthesis of heterocycles are reported here. The b,b-enamino nitriles 2, which were synthesized by known methods [12], are converted into the corresponding 3-amino-1H-pyrrole derivatives 3 by reaction with a-halogenated ketones, nitriles, or esters under basic conditions, a Thorpe -Ziegler cyclization (Scheme 1) [13] [14].…”

Efficient and Selective Construction of Pyrrolo[3,2-d]pyrimidine Derivatives

“…Compound 2 was obtained from the reaction of ethyl cyanocaetate with aniline and ethyl orthoformate in the presence of K 2 CO 3 , followed by reaction with ethyl 2-bromoacetate according to a literature report. 32 White crystals (yield: 82%); mp: 69-70°C (Lit. mp: 66-68 °C).…”