Studies with condensed aminothiophenes: Further investigation on the reactivity of condensed aminothiophenes toward electron poor and acetylenes under microwave heating

Abstract

The reaction of aminothienopyridazines 8a,b, aminothienocoumarin 13 and aminothienonaphthopyran 14 with enaminones 9, 17 and 20a,b under microwave irradiation affords either a mixture of both condensations C‐1 alkylation products 15 and 16 or amino moiety alkylation and diethylamine elimination or only one of these products depending on nature of substituents on the thiophene ring. On the other hand reaction of these condensed aminothiophenes with 3‐dimethylaminoacrylaldehyde afforded 24 and 25.

Recent developments in chemical reactivity of N,N-dimethylenamino ketones as synthons for various heterocycles

“…54 Further conrmation of this structure assignment was obtained via successful conversion of 90b into the thiophene 91 through hydrolysis of the alkylated amino moiety (Scheme 27). 56 Dienone 19 underwent analogous reactions with aminothienopyridazines 88a,b in a microwave oven at 560 W for 90 seconds to give rise to the expected N-alkylated products 92a,b. 56 A similar treatment of 6a with benzothienocoumarin 93 led to the corresponding enaminone 94 (Scheme 28).…”

“…56 Dienone 19 underwent analogous reactions with aminothienopyridazines 88a,b in a microwave oven at 560 W for 90 seconds to give rise to the expected N-alkylated products 92a,b. 56 A similar treatment of 6a with benzothienocoumarin 93 led to the corresponding enaminone 94 (Scheme 28). 56 Aminothiophene derivatives 85, 88a,b and 93 reacted with the N,N-dimethylenamino ketones 95a,b in a similar fashion yielding the corresponding secondary enaminones 95a,b, 96ad and 97a,b (Scheme 29).…”

“…56 A similar treatment of 6a with benzothienocoumarin 93 led to the corresponding enaminone 94 (Scheme 28). 56 Aminothiophene derivatives 85, 88a,b and 93 reacted with the N,N-dimethylenamino ketones 95a,b in a similar fashion yielding the corresponding secondary enaminones 95a,b, 96ad and 97a,b (Scheme 29). 56 In contrast to the behavior of aminothiophene toward N,Ndimethylenamino ketones, interaction 55 of compounds 1d,e with 88a in acetic acid at reux for three hours gave C-1 alkylation products 99a,b instead of the N-alkylated derivatives 98a,b that would be expected by analogy with the other reports 42,56 on the reactivity of nitrogen nucleophiles toward electron poor olens (Scheme 30).…”

“…56 Aminothiophene derivatives 85, 88a,b and 93 reacted with the N,N-dimethylenamino ketones 95a,b in a similar fashion yielding the corresponding secondary enaminones 95a,b, 96ad and 97a,b (Scheme 29). 56 In contrast to the behavior of aminothiophene toward N,Ndimethylenamino ketones, interaction 55 of compounds 1d,e with 88a in acetic acid at reux for three hours gave C-1 alkylation products 99a,b instead of the N-alkylated derivatives 98a,b that would be expected by analogy with the other reports 42,56 on the reactivity of nitrogen nucleophiles toward electron poor olens (Scheme 30). Similar to the behavior of 73a toward 1d,e enaminoketone 23 reacted with thienocoumarin 85 under microwave heating in the presence of few drops of acetic acid to produce only the C-1 alkylation product 100.…”

Solvent‐free one‐pot synthesis of some azo disperse dyes under microwave irradiation: Dyeing of polyester fabrics

“…Here, a simple synthetic method for azo disperse dyes was carried out in one pot in the presence or absence of solvents by inducing with microwave irradiation. Because of the easy availability of microwave ovens, microwave irradiation has been recently used to promote various types of organic reactions19, 20 including those in the absence of solvents “dry media,”21, 22 which were carried out often on solid mineral supports. The application of microwave technique to the synthesis of azo disperse dyes in the solid state without any mineral support were studied and found that the reaction occurred in a very short time with high yields.…”