An efficient, regiocontrolled synthesis of 5-aryl-2-carbethoxypyrroles from 3-aryl-3-chloropropeniminium salts

Five‐Membered Heterocycles: Pyrrole and Related Systems

“…A related reaction involving the salt 91, which is readily available from 3-acetylthiophene, leads to the thienylpyrrole 92 (Scheme 4.28) [134]. Similar chemistry has also been employed for the preparation of 5-arylpyrrole-2-carboxylates [135] and of various 3,4-disubstituted pyrrole-2-carboxylates [136]. Since its introduction, the van Leusen pyrrole synthesis has enjoyed considerable popularity, as it provides convenient access to 3,4-disubstituted pyrroles from the [137].…”

Conjugated Azomethine Ylides

“…[52] Regiochemically controlled synthesis of substituted pyrroles can be achieved via 1,5-electrocyclization of vinyl azomethine ylides formed from the condensation of vinylogous Scheme 24. iminium salts or their derivatives with α-amino esters (Scheme 25). [53][54][55] Reaction of 2-arylvinamidinium salts 110a with sarcosine gives 4-aryl-2-ethoxycarbonyl-N-substituted pyrroles 111, whereas starting with 1-arylvinamidinium salts 110b yields 2,3-disubstituted pyrroles 112. However, the reaction of 1-arylvinamidinium salts 110b with glycine ethyl ester leads to 2,5-disubstituted pyrroles 114.…”

Synthesis and Cytotoxicity of 2,4-Disubstituted and 2,3,4-Trisubstituted Brominated Pyrroles in Murine and Human Cultured Tumor Cells

“…The starting materials (2,4-disubstituted pyrroles) used in the following procedures have been previously reported [1][2][3][4] . All purified compounds gave a single spot upon TLC analysis on silica gel 7GF with an ethyl acetate/hexane mixture [30/70] as eluent.…”

“…Previously, we have described the regiochemically controlled synthesis of a variety of highly functionalized pyrroles [1][2][3][4] which are structurally related to a number of bioactive marine natural products [5,6] . We have recently reported the cytotoxicity of some of these derivatives in murine and human tumor cultured cells [7] including suspended as well as selected solid tumors.…”