Brazilian Chemistry: always shining brightly!

Synthetic Exploration of α‐Diazo γ‐Butyrolactams

“…Alternatively, this transformation may proceed via protonation of the α‐diazocarbonyl moiety followed by elimination of a nitrogen molecule. 3‐Pyrrolin‐2‐ones are versatile substrates for addition of organometallic compounds, Michael addition and 1,3‐dipolar cycloaddition . At the same time, the principal methods employed in their preparation are olefin metathesis and oxidative elimination of α‐phenylselenyl lactams , .…”

Efficient Synthesis of Highly Functionalised 5-oxo-4,5-Dihydro-1H-Pyrroles and 5-Oxo-2,5-Dihydro-1H-Pyrroles Derivatives

“…IR spectra were measured on a Shimadzu IR-460 spectrometer. 1 H and 13 C NMR spectra were measured (CDCl 3 solution) with a Bruker DRX-300 Avance spectrometer at 300.13 and 75.467 MHz, respectively. Elemental analyses were performed using a Heraeus CHN-O-Rapid analyzer.…”

“…Compound 6 apparently isomerises under the reaction conditions to produce the 5-oxo-4,5-dihydropyrrole ring system (4) (Scheme 2). 1 H NMR spectroscopy was used to distinguish structure 4 from the primary adduct, the 5-oxo-2,5-dihydropyrrole derivative (6). Thus, each of the products exhibited a methine hydrogen resonance at about δ = 5.16 and 5.12 ppm.…”

“…Then, the positively charged ion is attacked by the conjugate base of the NH-acid to form phosphorane 10, which is converted to pyrrole derivative 8. 1 H NMR spectroscopy was used to distinguish structure 8 from the 5-oxo-4,5-dihydropyrrole derivative. Thus, each of the products exhibited a methine hydrogen resonance at about δ = 5.34, 5.32 and 5.33 ppm.…”

“…N-Substituted pyrrolines derivatives are important starting materials for the preparation of a variety of biologically active compounds due to their ability to react as acceptors in conjugate addition reactions of organocuprates, enolates and nitrogen nucleophiles, beyond suffering hydroxylation, epoxidation, cyclopropanation and cycloaddition reactions. [1][2][3][4][5][6] Fivemembered ring lactams have successfully been used in routes to various alkaloids and are suitable precursors for unusual γ-amino acids such as statine and its analogues. [7][8][9][10][11][12][13][14][15][16][17] Despite their wide applicability, available routes for the synthesis of N-substituted pyrrolines derivatives are limited.…”