85684-93-1Relevant academic research and scientific papers
The Protecting-Directing Role of the Trityl Group in Syntheses of Pyrrole Derivatives: Efficient Preparations of 1-H-Pyrrole-3-carboxylic Acid and 3-Acyl, 3-Amino, and 3-Bromo-1-tritylpyrroles
Chadwick, Derek J.,Hodgson, Simon T.
, p. 93 - 102 (2007/10/02)
Trifluoroacetylation, formylation, and bromination of 1-tritylpyrrile occur regioselectively at the 3-position in high yields.Quantitative hydrolysis of the 3-trifluoroacetyl derivative and removal of the trityl group from the resulting acid with sodium in liquid ammonia furnishes a new, short, high-yielding synthessis of the simple 1-H-pyrrole-3-carboxylic acid. 1-Tritylpyrrole-3-carboxylic acid has been converted efficiently into 3-aminopyrroles via Curtius rearrangement of the derived azide: 3-amino-1-tritylpyrrole appears to exist in solution exclusively as its imino-Δ4-pyrroline tautomer. 1-H-3-t-Butyloxycarbonylaminopyrrole udergoes trifluoroacetylation regioselectively at the 2-position.Metallation of 1-tritylpyrrole with butyl-lithium in hexamethylphosphoric triamide gives rise to the unexpected products 9-phenylfluorene, 1-methoxycarbonylpyrrole and methyl triphenylmethylacetate (after work-up of the lithio-intermediates with carbon dioxide and methylation of the resulting acids).
