pyrrole-based amino acids have been prepared through the microwave assisted Paal–Knorr reaction of 1–4 ketoesters derived from the corresponding β-ketoester with a functional homologation. The carboxylic group is located in position 3 of the pyrrole, whereas the amino group, protected with the Cbz moiety, is present on the side chain in positions 1 or 2. These compounds were used to prepare constrained oligopeptides
Microwave-Assisted Paal−Knorr Reaction. A Rapid Approach to Substituted Pyrroles and Furans
作者:Giacomo Minetto、Luca F. Raveglia、Maurizio Taddei
DOI:10.1021/ol0362820
日期:2004.2.1
An array of tetrasubstituted pyrroles (and trisubstituted furans) was obtained using a simple three-step procedure. Functional homologation of beta-ketoester with an aldehyde followed by oxidation gave a series of differently substituted 1,4-dicarbonyl compounds that can be rapidly cyclized with the Paal-Knorr procedure carried out under microwave irradiation.
REISSIG H.-U., TETRAHEDRON LETT., 1981, 22, NO 31, 2981-2984