Indoles via Knoevenagel–Hemetsberger reaction sequence

Indole‐2‐carboxamide Derivatives as Potent Urotensin‐II Receptor (UT) Antagonists

“…The general synthetic route used for the preparation of substituted indole‐2‐carboxamide derivatives 2–8 is outlined in Scheme . The substituted ethyl indole‐2‐carboxylates 9 , employing previously reported methods, were reacted with alkyl or sulfonyl halide in the presence of potassium carbonate as base in N,N ‐dimethylformamide (DMF) to give corresponding indole‐2‐carboxylates 10 including methyl, ethyl, benzyl, methylsulfonyl, and benzenesulfonyl groups at 1‐position. In addition, 1‐aryl substituted indoles were readily synthesized by copper mediated N ‐arylation reactions of 10 with several aryl boronic acids using pyridine .…”

Pyrroloindole-Based Dynamic Combinatorial Chemistry

“…It is aromatic (14 π electrons) and bears cysteine appendages on the α, α' positions that confer it water solubility and ability to be involved in disulfide exchange (Figure 1). The initial synthesis of the core followed a previously published procedure [55]. The first step involved the formation of ethyl azidoacetate 2, which was used in a Knoevenagel-type condensation with terephthaldehyde to yield compound 4.…”

“…The final building block L-PI was obtained in 8 steps, none of which required laborious purification (experimental details in Supplementary Materials Section 1). The initial synthesis of the core followed a previously published procedure [55]. The first step involved the formation of ethyl azidoacetate 2, which was used in a Knoevenagel-type condensation with terephthaldehyde to yield compound 4.…”

Synthesis of Linearly Fused Benzodipyrrole Based Organic Materials

“…Liotta et al prepared the pyrrolo[2,3- f ]indole scaffold starting from terephthaldehyde 164 . This compound is condensed with two equivalents of ethyl-2-azidoacetate 165 , after which the obtained compound 166 is thermally closed by nitrene insertion to obtain the final pyrrolo[2,3- f ]indole 167 in 72% yield (Scheme 44) [94].…”