3-amino-2,2-dimethylpropanoic acid;hydrochloride

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

Procedure: A solution of 3-amino-2,2-dimethylpropanoic acid hydrochloride (1.0 g, 6.5 mmol, 1.0 eq.) in 10 mL of 10% Na2CO3 was added to a solution of 1-{[(9H-fluoren-9-ylmethoxy)carbonyl]oxy}pyrrolidine-2,5-dione (2.3 g, 6.5 mmol, 1.0 eq.) in 10 mL of DME. The reaction was allowed to stir at room temperature overnight. Reaction was concentrated to a smaller volume and then washed two times with ether. The aqueous layer was acidified to pH<2 with concentrated HCl and then extracted three times with a 10% methanol 90% dichloromethane solution. The organics where combined before being washed with 1M HCl and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo producing #124 (2.2 g, 98%) as a white solid. LC-MS (Protocol Q1): m/z 362.0 [M+Na+] retention time=0.89 minutes. Reaction was concentrated to a smaller volume washed two times with ether extracted three times with a 10% methanol 90% dichloromethane solution before being washed with 1M HCl and brine The organic layer was dried over sodium sulfate concentrated in vacuo

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

Procedure: To 3-amino-2,2-dimethylpropanoic acid, hydrochloride salt (250 mg, 1.63 mmol, 1 eq.) in dichloromethane (4 mL, 0.4 M) was added diisopropylethylamine (859 μL, 4.88 mmol, 3 eq.) followed by (9H-fluoren-9-ylmethoxy)carbonyl chloride (473 mg, 1.79 mmol, 1.1 eq.) The reaction was stirred for 18 hours and then concentrated in vacuo. The residue was taken up in ethyl acetate (3 mL) and washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine. The organic layer was dried over sodium sulfate, filtered, and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #93 (250 mg, 45%) as an oil. 1H NMR (400 MHz, DMSO-d6) δ 12.22 (s, 1H), 7.89 (d, J=7.4 Hz, 2H), 7.72 (d, J=7.4 Hz, 2H), 7.38-7.44 (m, 2H), 7.27-7.35 (m, 3H), 4.18-4.30 (m, 3H), 3.16 (d, J=6.2 Hz, 2H), 1.05 (s, 6H). concentrated in vacuo washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine The organic layer was dried over sodium sulfate filtered purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane)

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

Procedure: To 3-amino-2,2-dimethylpropanoic acid, hydrochloride salt (250 mg, 1.63 mmol, 1 eq.) in dichloromethane (4 mL, 0.4 M) was added diisopropylethylamine (859 μL, 4.88 mmol, 3 eq.) followed by (9H-fluoren-9-ylmethoxy)carbonyl chloride (473 mg, 1.79 mmol, 1.1 eq.) The reaction was stirred for 18 hours and then concentrated in vacuo. The residue was taken up in ethyl acetate (3 mL) and washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine. The organic layer was dried over sodium sulfate, filtered, and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #93 (250 mg, 45%) as an oil. 1H NMR (400 MHz, DMSO-d6) δ 12.22 (s, 1H), 7.89 (d, J=7.4 Hz, 2H), 7.72 (d, J=7.4 Hz, 2H), 7.38-7.44 (m, 2H), 7.27-7.35 (m, 3H), 4.18-4.30 (m, 3H), 3.16 (d, J=6.2 Hz, 2H), 1.05 (s, 6H). concentrated in vacuo washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine The organic layer was dried over sodium sulfate filtered purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane)

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

Procedure: To 3-amino-2,2-dimethylpropanoic acid, hydrochloride salt (250 mg, 1.63 mmol, 1 eq.) in dichloromethane (4 mL, 0.4 M) was added diisopropylethylamine (859 μL, 4.88 mmol, 3 eq.) followed by (9H-fluoren-9-ylmethoxy)carbonyl chloride (473 mg, 1.79 mmol, 1.1 eq.) The reaction was stirred for 18 hours and then concentrated in vacuo. The residue was taken up in ethyl acetate (3 mL) and washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine. The organic layer was dried over sodium sulfate, filtered, and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #93 (250 mg, 45%) as an oil. 1H NMR (400 MHz, DMSO-d6) δ 12.22 (s, 1H), 7.89 (d, J=7.4 Hz, 2H), 7.72 (d, J=7.4 Hz, 2H), 7.38-7.44 (m, 2H), 7.27-7.35 (m, 3H), 4.18-4.30 (m, 3H), 3.16 (d, J=6.2 Hz, 2H), 1.05 (s, 6H). concentrated in vacuo washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine The organic layer was dried over sodium sulfate filtered purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane)

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

Procedure: A solution of 3-amino-2,2-dimethylpropanoic acid hydrochloride (1.0 g, 6.5 mmol, 1.0 eq.) in 10 mL of 10% Na2CO3 was added to a solution of 1-{[(9H-fluoren-9-ylmethoxy)carbonyl]oxy}pyrrolidine-2,5-dione (2.3 g, 6.5 mmol, 1.0 eq.) in 10 mL of DME. The reaction was allowed to stir at room temperature overnight. Reaction was concentrated to a smaller volume and then washed two times with ether. The aqueous layer was acidified to pH<2 with concentrated HCl and then extracted three times with a 10% methanol 90% dichloromethane solution. The organics where combined before being washed with 1M HCl and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo producing #124 (2.2 g, 98%) as a white solid. LC-MS (Protocol Q1): m/z 362.0 [M+Na+] retention time=0.89 minutes. Reaction was concentrated to a smaller volume washed two times with ether extracted three times with a 10% methanol 90% dichloromethane solution before being washed with 1M HCl and brine The organic layer was dried over sodium sulfate concentrated in vacuo

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

Procedure: To 3-amino-2,2-dimethylpropanoic acid, hydrochloride salt (250 mg, 1.63 mmol, 1 eq.) in dichloromethane (4 mL, 0.4 M) was added diisopropylethylamine (859 μL, 4.88 mmol, 3 eq.) followed by (9H-fluoren-9-ylmethoxy)carbonyl chloride (473 mg, 1.79 mmol, 1.1 eq.) The reaction was stirred for 18 hours and then concentrated in vacuo. The residue was taken up in ethyl acetate (3 mL) and washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine. The organic layer was dried over sodium sulfate, filtered, and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #93 (250 mg, 45%) as an oil. 1H NMR (400 MHz, DMSO-d6) δ 12.22 (s, 1H), 7.89 (d, J=7.4 Hz, 2H), 7.72 (d, J=7.4 Hz, 2H), 7.38-7.44 (m, 2H), 7.27-7.35 (m, 3H), 4.18-4.30 (m, 3H), 3.16 (d, J=6.2 Hz, 2H), 1.05 (s, 6H). concentrated in vacuo washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine The organic layer was dried over sodium sulfate filtered purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane)