N-Bromosuccinimide assisted oxidation of 5-aminopyrazoles: formation of bis diazenylderivatives

3-Aminopyrroles and their application in the synthesis of pyrrolo[3,2-d]pyrimidine (9-deazapurine) derivatives

“…For example, the 1 H NMR spectrum of compound 4a showed the absence of a signal for a methylene function and the presence of a two protons D 2 O exchangeable signal at δ = 6.11 ppm for the amino function and a singlet for the pyrrole 5-H proton at δ = 7.84 ppm. 13 C NMR and mass spectra of compound 4a are in agreement with the proposed structure. When the reaction was carried out in excess of chloroacetonitrile, the N-substituted product 5 was obtained (Scheme 1).…”

“…The structure of compounds 4a-d was established on the basis of elemental analysis, IR, mass, 1 H and 13 C NMR spectral data studies (cf. Experimental Section).…”

“…IR spectra were registered on a Perkin Elmer FTIR-1600 using Nujol emulsions between NaCl plates. 1 H NMR (300 or 400 MHz) and 13 C NMR (75.4 or 100.62 MHz) spectra were recorded in deuterated dimethylsulfoxide [D 6 ]DMSO or deuterated chloroform CDCl 3 on a Varian Unity Plus Spectrometer using tetramethylsilane (TMS) as an internal reference, and results are expressed as δ values. Double resonance, HMQC and HMBC experiments were carried out for complete assignment of proton and carbon signals in the NMR spectra, whenever possible.…”

“…[5][6][7][8][9] Recently we described several efficient approaches to heteroaromatic systems using functionally substituted enamine precursors. [10][11][12][13][14] In continuation to our interest in the chemistry of β,β-enaminonitriles we report here the results of our work aimed at exploring the potential utility of 3-anilino-2-cyanoacrylonitrile in the heterocyclic synthesis. The synthesized β,β-enaminonitriles 2 are converted into the corresponding 3-aminopyrrole derivatives by reaction with α-haloketones under basic conditions, a Thorpe-Ziegler cyclization.…”

Synthesis of 3-indolylazoles and meridianin derivatives from indolyl enaminonitriles

“…Following our interest in the chemistry of -enaminonitriles, [10][11][12][13] in this manuscript we describe our most recent results that explore the potential of 3(2E)-3-dimethylamino-2-(1H-indol-3-yl)-propenoate in the synthesis of 5´-cyanomeridianin C, G and 3-heteroarylindoles. Commercially available indole and indole-3-carboxaldehyde were employed as the starting materials giving access to the meridianin analogs 4a-c in a straightforward three-step synthesis following the Bredereck approach 7 (Scheme 1), and to 14 from one-pot synthesis as shown in Scheme 3.…”