143064-84-0Relevant academic research and scientific papers
Synthesis of pyrroles from benzyl isocyanoacetate
Lash,Bellettini,Bastian,Couch
, p. 170 - 172 (1994)
Benzyl esters of 5-unsubstituted pyrrole-2-carboxylic acids were prepared in excellent yields by the base-catalyzed condensation of benzyl isocyanoacetate with α-acetoxynitro compounds, or nitro-alkenes, in refluxing tetrahydrofuran. These pyrrolic products are important intermediates in the synthesis of porphyrins and related compounds.
Total synthesis of cyclopentenoporphyrins of sedimentary origin: deoxophylloerythroetioporphyrin, chlorophyll c fossils and related compounds.
Bauder, Claude,Ocampo, Ruben,Callot, Henry J.
, p. 5135 - 5150 (2007/10/02)
This article describes the total synthesis of seven porphyrins, fossils of chlorophyll derivatives, isolated from sedimentary sources and possess five-membered rings fused to the porphyrin nucleus, this additional ring being placed between positions 13,15 or 15,17.This ring was built from vinyl, hydroxyethyl or isopropenyl groups under strong acidic conditions. Key words: sedimentary porphyrins, chlorophyll geochemistry, total synthesis, E-ring formation.
Porphyrins with Exocyclic Rings. 2. Synthesis of Geochemically Significant Tetrahydrobenzoporphyrins from 4,5,6,7-Tetrahydro-2H-isoindoles
May, Donald A.,Lash, Timothy D.
, p. 4820 - 4828 (2007/10/02)
Benzo- and tetrahydrobenzoporphyrins are widespread constituents of oil shales and petroleum.Although the origins of these materials are not known, a case is made for divinylchlorophyll a, a widespread pigment in marine algae, being the precursor to many of these geoporphyrins.Total syntheses of four tetrahydrobenzoporphyrins related to etioporphyrin III are described.Tetrahydroisoindoles were prepared by condensation of isocyanoacetates with 1-nitrocyclohexene in the presence of DBU or by reaction of aminomalonates with 2-formylcyclohexanone.Condensation of 3-unsubstituted 4,5,6,7-tetrahydro-2H-isoindoles 23c and 23d with (acetoxymethyl)pyrroles in the presence of Montmorillonite clay gave dipyrrylmethanes 28a and 36a in excellent yield.Hydrogenolysis of the benzyl esters and subsequent acid-catalyzed condensation with pyrrole aldehydes 37a and /or 37b gave a series of a,c-biladiene dihydrobromides.Copper(II) mediated cyclization of the a,c-biladienes 32, 33, 35, and 38, followed by demetallation with 15percent sulfuric acid-trifluoroacetic acid, gave four isomeric tetrahydrobenzoporphyrins 10-13 in unusually high yield.This work provides a general route for the synthesis of these important porphyrin molecular fossils.
