5-Aryl-2-furancarbaldehyde Hydrazones and Related Compounds

Abstract

A series of 5-aryl-2-furancarbaldehyde 2,6-dialkylphenylhydrazones (Ia - Iv) and dimethylhydrazones (IIa - IIf) as well as related compound benzo[b]furan-2-carbaldehyde dimethylhydrazone (III) were prepared. Compounds Ia - Iv were synthesized by condensing 5-aryl-2-furancarbaldehydes with 2,6-dialkylphenylhydrazines, compounds IIa - IIf were obtained from the same starting compounds and N,N-dimethylhydrazine. The intermediate 5-aryl-2-furancarbaldehydes were prepared by reaction of aryldiazonium chlorides with 2-furancarbaldehyde. The structure of the compounds were proven by 1H, 13C and 15N NMR spectra.

Synthesis and Reactions of Furo[2,3-b]pyrroles

“…The parent furo [2,3-b]pyrrole has not been reported. In the past we were interested in syntheses and studies of the reactions of furo [3,2-b]pyrroles and their benzo or dibenzo derivatives [4][5][6][7][8][9].…”

Effect of microwave irradiation on reaction of furo[3,2-b]pyrrole and furo[2,3-b]pyrrole-2-carbaldehydes with some active methylene compounds

“…1 In continuation of our program aimed at developing efficient syntheses of fused oxygen-nitrogen containing heterocycles we have reported the use of substituted furo [3,2-b] and furo [2,3-b]pyrroles in the synthesis. [2][3][4][5][6][7][8] In our previous studies, 6 comparing the course of Diels-at C2 results in the reactivity of both systems being comparable.…”

“…This paper presents a synthesis of methyl 6-(methoxymethyl)furo [3,2-b]pyrrole-5-carboxylate (1d), which was obtained more effectively by direct substitution of in situ prepared sodium salt of 1a in DMF, and its formylation under the condition used in ref. 2 In this reaction, 2-formylated product 2d was Methyl 2-(4-oxo-2-thioxothiazolidin-5-ylidene)methyl-4H-furo[3,2-b]pyrrole-5-carboxylate (4a) and its 4-Me, 4-Bn and 4-MOM derivatives 4b-4d were obtained by reactions of 2a-2d with 2-thioxothiazolidine-4-one (rhodanine) in acetic acid in the presence of freshly fused potassium acetate (Scheme 2).…”

“…For example condensations of thiohydantoin with aromatic aldehydes without solvents 10 and substituted 3-formylchromones in acetic anhydride 11 under microwave irradiation have been described. Results and Discussion In our previous paper 2 , we described the preparation of 1b and 1c from methyl 4H-furo [3,2-b]pyrrole-5-carboxylate (1a) under phase transfer catalysis conditions and the formylation of these compounds under conditions of the Vilsmeier reaction. This paper presents a synthesis of methyl 6-(methoxymethyl)furo [3,2-b]pyrrole-5-carboxylate (1d), which was obtained more effectively by direct substitution of in situ prepared sodium salt of 1a in DMF, and its formylation under the condition used in ref.…”

“…The aim of this study was to synthesise some new condensation products of furo [3,2-b]pyrrole (2) and furo [2,3-b]pyrrole-type aldehydes (3) by reaction with active methylene compounds (Schemes 2 and 3) and to compare the "classical" method with the effect of microwave irradiation and to find conditions in to increase the yield of the condensations. As it was shown before, 9 microwave irradiation can shorten the duration of condensation reactions.…”