Synlett 2021; 32(11): 1146-1150
DOI: 10.1055/a-1492-8216
letter

Heterocycle–Heterocycle Strategy for 4,5-Disubstituted Pyrrolidine 2,3-Diones: Reductive Rearrangement Approach from Isoxazole Esters

a   Syngenta Biosciences Pvt. Ltd. Santa Monica Works, Corlim, ­Ilhas, Goa 403110, India
b   Department of Chemistry, Mangalore University, Mangalagangothri, 574199, Karnataka, India
,
Vaibhav Jadhav
a   Syngenta Biosciences Pvt. Ltd. Santa Monica Works, Corlim, ­Ilhas, Goa 403110, India
,
Mukul Lal
a   Syngenta Biosciences Pvt. Ltd. Santa Monica Works, Corlim, ­Ilhas, Goa 403110, India
b   Department of Chemistry, Mangalore University, Mangalagangothri, 574199, Karnataka, India
› Author Affiliations


Abstract

The work demonstrates the heterocycle–heterocycle interconversion strategy to access 4,5-disubstituted 3-hydroxy-2-pyrrolidinone in moderate to good yields (50–80%). The approach has a distinct advantage over a multicomponent reaction approach as it allows access to unsubstituted 3-hydroxy-2-pyrrolidinone at the nitrogen position for further functionalization.

Supporting Information



Publication History

Received: 10 April 2021

Accepted after revision: 27 April 2021

Accepted Manuscript online:
27 April 2021

Article published online:
10 May 2021

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  • References and Notes

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    • 5b Levy SB, Alekshun MN, Podlogar BL, Ohemeng K, Verma AK, Warchol T, Bhatia B, Bowser T, Grier M. US Patent Appl. US2005124678 (A1), 2005
  • 7 Kamath P, Viner RC, Smith SC, Lal M. Synlett 2017; 28: 1341
  • 10 General Procedure for the Synthesis of Isoxazoles 6To a solution of oxime (1.0 mmol, 1.0 equiv.) in DMF (2.0 mL) at room temperature was added N-chlorosuccinimide (1.1 mmol, 1.1 equiv.) and stirred for 60 min. Dimethylacetylenedicarboxylate (DMAD) was added in one portion (1.1 mmol, 1.1 equiv.). Then, a solution of triethylamine (1.0 mmol, 1 equiv.) in DMF (1.0 mL) was added. The solution was stirred at RT till the reaction completes. The reaction mass poured into ice water, stirred for 10 min and extracted with ethyl acetate. The combined organic layer was washed with brine solution, dried over anhydrous sodium sulfate, and concentrated in vacuum. Purification if necessary was done by column chromatography using cyclohexane and ethyl acetate as mobile phase. §#BLD#§Dimethyl 3-Phenylisoxazole-4,5-dicarboxylate (6a)
  • 11 Prepared using the general procedure by starting with benzaldehyde oxime (3.0 mmol). Off-white solid, 71% yield; mp 62–64 °C. 1H NMR (400 MHz, CDCl3): δ = 7.71–7.70 (d, J = 7.3 Hz, 2 H), 7.54–7.46 (m, 3 H), 4.10 (s, 3 H), 3.92 (s, 3 H) ppm. 13C NMR (101 MHz, CDCl3): δ = 161.8, 161.2, 159.3, 156.4, 130.6, 128.8, 128.1, 126.8, 116.04, 53.3, 53.1 ppm. HRMS (ESI): m/z [M + H]+ calcd for C13H11NO5: 261.0637; found: 261.0634.
  • 12 General Procedure for the Synthesis of Pyrrolidine Diones 1a–lTo a solution of isoxazole ester (0.5 g) in acetic acid (5.0 mL) was added portionwise Fe powder (10.0 equiv.) at 100 °C. During the addition, the colorless solution turned to dark brown. The reaction was monitored by LC–MS and after complete conversion the reaction mass was cooled to RT and poured into saturated aqueous sodium bicarbonate solution (50.0 mL). The mixture was filtered over a bed of Celite and the filtrate was extracted with diethyl ether before acidification with concd HCl to pH 1. During acidification the color of the solution turned from pale yellow to red and colorless at pH 1. The product was extracted to ethyl acetate layer and concentrated to get target molecule as solid (50–80%).Methyl-4-hydroxy-5-oxo-2-phenyl-1,2-dihydropyrrole-3-carboxylate (1a)Prepared using the general procedure by starting with dimethyl 3-phenylisoxazole-4,5-dicarboxylate (3.0 mmol). Off-white solid, 71% yield; decomposes above 140 °C. 1H NMR (400 MHz, DMSO-d 6): δ = 11.44 (s, 1 H), 9.27 (s, 1 H), 7.35–7.18 (m, 5 H), 5.18 (s, 1 H), 3.53 (s, 3 H) ppm. 13C NMR (101 MHz, DMSO-d 6): δ = 166.3, 162.7, 154.2, 138.4, 128.3, 127.8, 127.1, 112.1, 56.4, 50.9 ppm. HRMS (ESI): m/z [M + H]+ calcd for C12H11NO4: 233.0688; found: 233.0684.