butyl 2,2-dimethyl-4-oxo-3H-pyran-6-carboxylate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of Indalon (230 mg) and 2R,5R-5-butyl-methyl-2-(5-methylfuran-2-yl) imidazolidin-4-one (55 mg) in dry ether (4.6 mL) was stirred and cooled at ice bath temp (0-4° C.) as t-Butyl Hantzch ester (346 mg) and trichloroacetic acid (32 mg) were added sequentially. The resulted yellow solution was stirred at ice bath temp for 3 days, and monitored by TLC. The reaction mix was passed through a short pad of silica gel and eluted with ether (60 mL). Concentration of the ether and purified by flash chromatography (20% EtOAc in Hexane) gave 204 mg (88%) of the product as oil: 1H NMR (400 MHz, CDCl3) δ 4.46 (dd, 1H, J=4.0, 11.0 Hz), 4.19 (td, 2H, J=2.7, 6.7 Hz), 2.58 (dd, 1H, J=1.6, 14.0 Hz), 2.56 (d, 1H, J=13.2), 2.50 (s, H, J=13.2 Hz), 2.32 (dd, 1H, J=1.6, 14.0 Hz), 1.64 (m, 2H), 1.46 (s, 3H), 1.37 (m, 2H), 1.23 (s, 3H), 0.94 (t, 3H, J=7.4 Hz); 13C NMR (CDCl3, 100 MHz) ä 205.2, 170.1, 76.2, 70.0, 65.4, 52.9, 43.5, 30.5, 28.6, 28.0, 23.8, 19.0, 13.6. were added sequentially The reaction mix eluted with ether (60 mL) Concentration of the ether and purified by flash chromatography (20% EtOAc in Hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of Indalon (230 mg) and 2R,5R-5-butyl-methyl-2-(5-methylfuran-2-yl) imidazolidin-4-one (55 mg) in dry ether (4.6 mL) was stirred and cooled at ice bath temp (0-4° C.) as t-Butyl Hantzch ester (346 mg) and trichloroacetic acid (32 mg) were added sequentially. The resulted yellow solution was stirred at ice bath temp for 3 days, and monitored by TLC. The reaction mix was passed through a short pad of silica gel and eluted with ether (60 mL). Concentration of the ether and purified by flash chromatography (20% EtOAc in Hexane) gave 204 mg (88%) of the product as oil: 1H NMR (400 MHz, CDCl3) δ 4.46 (dd, 1H, J=4.0, 11.0 Hz), 4.19 (td, 2H, J=2.7, 6.7 Hz), 2.58 (dd, 1H, J=1.6, 14.0 Hz), 2.56 (d, 1H, J=13.2), 2.50 (s, H, J=13.2 Hz), 2.32 (dd, 1H, J=1.6, 14.0 Hz), 1.64 (m, 2H), 1.46 (s, 3H), 1.37 (m, 2H), 1.23 (s, 3H), 0.94 (t, 3H, J=7.4 Hz); 13C NMR (CDCl3, 100 MHz) ä 205.2, 170.1, 76.2, 70.0, 65.4, 52.9, 43.5, 30.5, 28.6, 28.0, 23.8, 19.0, 13.6. were added sequentially The reaction mix eluted with ether (60 mL) Concentration of the ether and purified by flash chromatography (20% EtOAc in Hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of Indalon (230 mg) and 2R,5R-5-butyl-methyl-2-(5-methylfuran-2-yl) imidazolidin-4-one (55 mg) in dry ether (4.6 mL) was stirred and cooled at ice bath temp (0-4° C.) as t-Butyl Hantzch ester (346 mg) and trichloroacetic acid (32 mg) were added sequentially. The resulted yellow solution was stirred at ice bath temp for 3 days, and monitored by TLC. The reaction mix was passed through a short pad of silica gel and eluted with ether (60 mL). Concentration of the ether and purified by flash chromatography (20% EtOAc in Hexane) gave 204 mg (88%) of the product as oil: 1H NMR (400 MHz, CDCl3) δ 4.46 (dd, 1H, J=4.0, 11.0 Hz), 4.19 (td, 2H, J=2.7, 6.7 Hz), 2.58 (dd, 1H, J=1.6, 14.0 Hz), 2.56 (d, 1H, J=13.2), 2.50 (s, H, J=13.2 Hz), 2.32 (dd, 1H, J=1.6, 14.0 Hz), 1.64 (m, 2H), 1.46 (s, 3H), 1.37 (m, 2H), 1.23 (s, 3H), 0.94 (t, 3H, J=7.4 Hz); 13C NMR (CDCl3, 100 MHz) ä 205.2, 170.1, 76.2, 70.0, 65.4, 52.9, 43.5, 30.5, 28.6, 28.0, 23.8, 19.0, 13.6. were added sequentially The reaction mix eluted with ether (60 mL) Concentration of the ether and purified by flash chromatography (20% EtOAc in Hexane)