C[Al](C)C.[Cl-].[NH4+:6].[CH:7]1([C:12]#[N:13])[CH2:11][CH2:10][CH2:9][CH2:8]1.C[O:15][C:16]([CH:18]1[CH2:22][CH2:21][CH2:20][C:19]1=O)=O.C([O-])([O-])=O.[K+].[K+]>C1(C)C=CC=CC=1.CO>[CH:7]1([C:12]2[N:6]=[C:16]([OH:15])[C:18]3[CH2:22][CH2:21][CH2:20][C:19]=3[N:13]=2)[CH2:11][CH2:10][CH2:9][CH2:8]1A solution of trimethylaluminum in toluene (2M, 25 mL, 50 mmol) was added slowly under nitrogen to a suspension of ammonium chloride (2.9 g, 54 mmol) in anhydrous toluene at 0° C.-5° C. The mixture was then stirred at a temperature in the range of 15° C. to 40° C. for 20 min before addition of a solution of cyclopentanecarbonitrile (3.13 mL, 30 mmol) in toluene. The resulting mixture was then heated at 80° C. under stirring for 10 hours. Thereafter, the mixture was cooled to a temperature in the range of 15° C. to 40° C. MeOH was slowly added to quench the reaction and stirred at a temperature in the range of 15° C. to 40° C. for 1 hour. Thereafter, the precipitate was filtered and washed with MeOH (3×30 mL). The filtrate and the washings were combined and concentrated under reduced pressure. After drying under vacuum, the crude solid (3.5 g) was dissolved in anhydrous EtOH (20 mL). Methyl-2-oxo-cyclopentanecarboxylate (3.1 mL, 25 mmol) and K2CO3 (4.14 g, 30 mmol) were added sequentially to this solution and the mixture was heated to reflux for a period over 6-15 hours. Thereafter, volatiles were evaporated under reduced pressure and the mixture was diluted with ice-water under stirring. The resultant precipitate was filtered, washed thoroughly with water followed by ether and dried under vacuum (4.6 g, 95.4% yield).
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