72. The halogenation of methyl pyrrole-2-carboxylate and of some related pyrroles

Abstract

Hodge and Rickards. The Halogenation of Methyl Pyrrole-2-carboxylate and ofSome Related Pyrroles.

Synthesis and anti‐staphylococcal activity of new halogenated pyrroles related to Pyrrolomycins F

“…The unusual chemical shift of 3-proton, more shielded than that expected from 2-carbonyl pyrroles, was due to the anisotropic effect of phenyl ring, twisted with respect to the plane of pyrrolic ring. According to what previously observed by P. Hodge and R. W. Rickards [14], the introduction of chlorine (or bromine) substituents into pyrrole rings cause only minor shifts in the resonance frequencies of the remaining hydrogens. On the contrary, the reaction of 8 with two molar equivalent of NCS gave the 4,5-dichloroderivative 9 (chemical shift for H-3 = 6.84…”

Pyoluteorin, a synthesis

“…The nuclear magnetic resonance (n.m.r.) spectra of these compounds were in agreement with their structures and followed from those of the starting dichloropyrrole esters (7). Although a pure sample of 2 was not obtained here, its spectrum was easily determined from that of its mixture with the isomeric ether 9 and that of pure 9.…”

Biologically active metabolites from Agelas mauritiana

“…This compound belonged to a different class of compounds and was identified as methyl N-methyl-4,5-dibromopyrrole-2-carboxylate (11) based on its 'H and 13C nmr spectra. This methyl ester is known as a synthetic product (12). It is possible that the ester is an artefact derived from the free acid, since similar observations have been made for 4,5-dibromopyrrole-2-carboxylic acid (13).…”