Mannich reactions of activated 4,6-dimethoxyindoles

Abstract

Mannich reactions of 4,6-dimethoxy-2,3-disubstituted indoles with bis(aminol)ethers catalysed by trifluoroacetic anhydride give pyrroloquinazoline derivatives through reaction at C7 and N1. 3-(4-Chlorophenyl)-4,6-dimethoxyindoles with electron withdrawing substituents at C7 react with formaldehyde and dimethylamine to give the corresponding 2-dimethylaminomethyl derivatives. They also react with N,Nbis(methoxymethyl)benzylamine catalysed by trichloromethylsilane to give Mannich base C2-linked diindole compounds. More strongly acidic conditions (e.g. trifluoroacetic anhydride) favour the formation of 2,2'diindolylmethanes, which are preferably generated from the indoles by reaction with formaldehyde in methanolic hydrochloric acid. Reactions of a Mannich base C2-linked diindole 7,7'-dicarbaldehyde with 1,2diaminobenzene and 1,2-diaminoethane give macrocyclic diimines, and a nickel(II) complex of one of these is reported.

Synthesis of New Methoxy Actived Mono and Bis-indole Compounds

“…As a result of the reaction, the desired product solidified in solution and was subjected to direct filtration. Compound 8 was obtained in high yield without any purification [36][37]. In the last step of the synthesis chain, the bis-indole 8 was heated with NBS in chloroform.…”

Pengembangan Sustainable Education Melalui Proyek Sanggar Literasi di Panti Asuhan PAKYM Surakarta

“…Dengan membaca, seseorang akan mendapatkan wawasan yang lebih luas dan dapat mengembangkan intelektual yang dimiliki pembaca. Adapun, menulis dalam konteks literasi adalah manifestasi dan apa yang dibaca, dipahami dan dialami (Purap & Purwono, 2021). Maka dari itu, budaya literasi di masyarakat harus ditanamkan sejak dini.…”

Indole macrocycles formed by diindolylmethane ring closure

“…We have previously shown that indolylesters can be prepared by the reaction of trichloroacetylindoles with alcohols. 20 Suitable precursors for macrocyclic compounds would be diindolyl diesters or diamides. Therefore two equivalents of the 7-trichloroacetylindole 1 21 were reacted with one equivalent of ethylene glycol in acetone containing potassium carbonate to give the diindolyl diester 2 in 75% yield (Scheme 1).…”

“…We have also shown that 2,2'-diindolylmethanes can be readily prepared from 3,7-disubstituted-4,6-dimethoxyindoles by the acid-catalysed reaction with formaldehyde or aryl aldehydes. 10,15,20,22 In general, alkyl aldehydes either fail to react or follow other paths. Consequently the diindolyl diester 2 was heated under reflux with formaldehyde in methanol containing concentrated hydrochloric acid, but no reaction occurred and the starting material remained intact.…”