5- Ethoxy-3-pyrrolin-2-one

Yavari and Bayat used similar fiinctionahty and replaced the aldol condensation with a Wittig reaction to prepare 3-ethoxy-3-pyrrolin-2-ones in a type ce fashion (Scheme 92 2002SC2527). Treatment of... 

DM AD (303) with oxamate 358 in the presence of triphenylphosphine gives the 3-ethoxy-3-pyrrolin-2-one 360 (2002SC2527) this reaction presumably proceeds via the Michael adduct 359, which then undergoes an intramolecular Wittig reaction. 

The checkers data are given. The submitters recovered 4.7-11.4 g. of succinimide and collected 15.6-21.2 g. (44-60% based on sodium ethoxide in Part A) of product, b.p. 65-70° (0.05 mm.). Based on the amount of unrecovered succinimide, the yield of product obtained by the checkers and submitters was 49-61% and 68-69%, respectively. The product is best stored in a freezer. If sufficient care is taken to exclude moisture, 2-ethoxy-pyrrolin-5-one is stable indefinitely. 

Irradiation of a ferf-butyl alcohol solution of 2-ethoxy-pyrroline-5-one (12) with Vycor filtered light from a 450-W mercury lamp results in formation of ferf-butyl N-(ethoxycyclopropyl) carbamate (13) in 73% isolated yield17,18 When the irradiation is conducted in the non-hydroxylic solvent, tetrahydrofuran, 1-ethoxycyclo-propyl isocyanate (20) can be isolated in 78% yield. Both 13 and 20 can be prepared in synthetically useful quantities. 

Ethoxypyrrolin-5-one l-Pyrrolin-5-one, 2-ethoxy- (8) 2H-Pyrrol-2-one, 5-ethoxy-3,4-dihydro- (9) (29473-56-1) tert-Butyl N-(l-ethoxycyclopropyl)carbamate Cyclopropanecar-bamic acid, 1-ethoxy-, tert-butyl ester (8) Carbamic acid, (1-ethoxycyclopropyl)-, 1,1-dimethylethyl ester (9) (28750-48-3 41879-49-6)... 

Cyclic imidate esters, 2-ethoxypyrrolin-5-one and 2-ethoxy-1II -indol-3-one, undergo 1,3-dipolar cycloaddition reactions with nitrile oxides, the reaction site being at the pyrroline C=N bond (317). Rigid and sterically congested pyrroline spiro compounds 148 demonstrate complete diastereofacial selection in site and regiospecific cycloaddition reactions with nitrile oxides to give products 149 (318). 

Pyroglutamics acids (5-oxoproHnes) can serve as precursors to 3-pyrro-Hn-2-ones via a similar formation of iminium intermediates and isomerization. Haidar and Ray discovered a direct conversion of pyroglutamic acid 464 to the 5-ethoxy-3-pyrrolin-2-one 466 by treatment with CAN and ethanol (Scheme 126 2008TL3659). The mechanism of the reaction likely involves the formation of iminium intermediate 465. Rigo and coworkers observed that the treatment of pyroglutamic acids with trifluoroacetic... 

---