81697-89-4Relevant articles and documents
PYRROLE CHEMISTRY. XXIV. THE VILSMEIER FORMYLATION AND CYANATION OF PYRROLE ACETALS. A SYNTHESIS OF PYRROLE-2,3,5-TRICARBOXALDEHYDE
Loader, Charles E.,Barnett, Graham H.,Anderson, Hugh J.
, p. 383 - 389 (2007/10/02)
The preparation of the acetals of a number of pyrrole mono- and dicarboxaldehydes is described.It is shown that, provided the reactivity of the unsubstituted ring positions on the pyrrole nucleus is not too low, a carboxaldehyde or a carbonitrile group may be substituted on the pyrrole ring using the Vilsmeier reaction or chlorosulfonyl isocyanate respectively. Vilsmeier formylation of the diacetal, 2,4-di(5,5-dimethyl-1,3-dioxan-2-yl)-pyrrole, followed by hydrolysis gave pyrrole-2,3,5-tricarboxaldehyde.