One-pot synthesis of 2-substituted thieno[3,2-b]indoles from 3-aminothiophene-2-carboxylates through in situ generated 3-aminothiophenes

Recent advances in the synthesis of thienoindole analogs and their diverse applications

“…It involves two steps, where the first step is the saponification of 3-aminoester with NaOH, and in the second step, this sodium salt reacts with arylhydrazine in glacial CH 3 COOH. In the latter step, decarboxylation of 3-aminothiophene-2-carboxylic acid takes place to give 3-aminothiophene, which further reacts with arylhydrazines under acidic conditions to form arylhydrazone, ultimately undergoing Fischer indolization to give the desired product 58 73.…”

An Effective Route to Dithieno[3,2-b:2′,3′-d]thiophene-Based Hexaheteroacenes

“…We recently reported an effective one-pot procedure for the synthesis of thieno[3,2-b]indole-containing compounds, including ring-fused structures, by the acid-promoted reaction of arylhydrazines with 2-unsubstituted 3-aminothiophenes generated in situ from 3-aminothiophene-2-carboxylates, which acted as synthetic equivalents of thiophen-3(2H)-ones. 42,43 We therefore selected the 3-amino-substituted BTTT molecules 7 as potential substrates for the construction of BTTTIs. Compounds 7a-c were synthesized from the corresponding benzo[b]thieno[2,3-d]thiophene-2-carboxylates 1a-c (Scheme 2).…”

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

“…Several routes have been reported to access these key compounds, the most developed being for the indole [14] derivatives using the Fischer indole synthesis involving sigmatropic rearrangements [15][16][17][18], nucleophilic and electrophilic cyclizations [19][20][21][22][23][24][25], reductive and oxidative cyclizations [26,27], and transition-metal catalysis [28][29][30][31][32][33][34][35][36][37]. There are fewer ways to [9], indolone [10], and cinnoline [11] derivatives).…”