Synthesis of Pyrrole Phosphonate Esters: Emphasis on Pyrrole NH Acids and Dialkylacetylenic Esters Substitution
Authors
Abstract:
Reaction of dialkyl acetylenedicarboxylates 1a-c andpyrrole derivatives 2a-e in the presence of triphenylphosphite (TPP) was investigated and the effect of the pyrrole substitution was established. Diastereoselectivity is observed with pyrroles, 2a,b, yieldingphosphonate ester derivatives 3a-f and 4,and their relative configuration is determined by 1H/13C and 31P NMR and confirmed by single X-ray diffraction. Similar reactions with higher degree of substitution of the pyrrole, 2c,e showed no diastereoselectivity.
similar resources
synthesis of pyrrole phosphonate esters: emphasis on pyrrole nh acids and dialkylacetylenic esters substitution
reaction of dialkyl acetylenedicarboxylates 1a-c andpyrrole derivatives 2a-e in the presence of triphenylphosphite (tpp) was investigated and the effect of the pyrrole substitution was established. diastereoselectivity is observed with pyrroles, 2a,b, yieldingphosphonate ester derivatives 3a-f and 4,and their relative configuration is determined by 1h/13c and 31p nmr and confirmed by single x-r...
full textConversion of 4-oxoproline esters to 4-substituted pyrrole-2-carboxylic acid esters.
The Grignard, Wittig, Tebbe, Horner-Emmons, and Reformatsky reactions of the 4-oxoproline esters gave the corresponding 4-alylated or 4-alkylidenated products, respectively. The products were properly treated with bases to cause aromatization, giving 4-substituted pyrrole-2-carboxylic acid esters such as methyl 4-methylpyrrole-2-carboxylate, which is a trail pheromone of Atta texana.
full textA Solvent-Induced Reversal of Regioselectivity in the Suzuki Coupling of Pyrrole Esters
During a study of the regioselectivity of the Suzuki coupling of dihalopyrrole esters, the first instance of a reversal of regioselectivity based upon a change in reaction solvent has been observed. It is believed that this change in regioselectivity is due to a change in solvation of the pyrrole ester, since a change in chemical shift values is observed for the C3 and C5 protons upon going fro...
full textA direct preparation of N-unsubstituted pyrrole-2,5-dicarboxylates from 2-azidocarboxylic esters.
A new and easy method for synthesis of symmetric pyrrole-2,5-dicarboxylate derivatives via a simple titanium(IV)-mediated oxidative dimerization of 2-azidocarboxylic esters is described. The process involves a transformation of titanium(IV) enolates into nonisolated 2-iminoesters, which undergo an oxidative coupling and ring closure to give the aromatic pyrrole system. A mechanism, scope and li...
full textSynthesis of fatty acyl CoA and other thiol esters using N-hydroxysuccinimide esters of fatty acids.
N-Hydroxysuccinimide esters of long-chain fatty acids have been used to synthesize the CoA and thioglycolic acid thiol esters of palmitic and 3-ketopalmitic acids in high yield and with a minimum of untoward side reactions.
full textLONG-ACTING CONTRACEPTIVE AGENTS: TESTOSTERONE ESTERS OF CYCLOALKYLCARBOXYLIC ACIDS
The synthesis of twenty five esters of testosterone (17β -hydroxyandrost- 4-en-3-one) is described. All esters are derivatives of cycloalkycarboxylic acids. Some of the esters possess α- , β -and/or & - substitution in the ester side-chain. The work was undertaken in order to evaluate long-acting male antifertility effect of such esters. Most of the compounds, especially compound No.1, wer...
full textMy Resources
Journal title
volume 27 issue 1
pages 105- 113
publication date 2008-03-01
By following a journal you will be notified via email when a new issue of this journal is published.
Hosted on Doprax cloud platform doprax.com
copyright © 2015-2023