Hydrochloric Acid → Methyl 6-[(isopropoxycarbonyl)amino]indane-5-carboxylate

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Reaction Steps

To a solution of a mixture of methyl 6-aminoindane-5-carboxylate and methyl 5-aminoindane-4-carboxylate (760 mg, 3.98 mmol), and pyridine (805 uL, 9.95 mmol) in CH2Cl2 (8 mL) at 0° C. under N2 was added isopropyl chloroformate (1 M in toluene) (3.98 mL, 3.98 mmol). The resulting mixture was stirred at room temperature for 16 h. 1M HCl was added to the reaction mixture and the organic layer was separated. The aqueous layer was extracted with CH2Cl2 (2×). The combined organic layers were dried (Na2SO4) and concentrated in vacuo. The residue was purified by flash chromatography (Si, hexanes/EtOAc) to afford methyl 6-[(isopropoxycarbonyl)amino]indane-5-carboxylate. LCMS calc.=300.1; found=299.9 (M+Na)+. 1H NMR (500 MHz, CDCl3) δ 10.43 (s, 1H); 8.34 (s, 1H); 7.86 (s, 1H); 5.06-5.00 (m, 1H); 3.92 (s, 3H); 2.96 (t, J=7.5 Hz, 2H); 2.88 (t, J=7.4 Hz, 2H); 2.13-2.07 (m, 2H); 1.33 (d, J=6.2 Hz, 6H). Methyl 5-[(isopropoxycarbonyl)amino]indane-4-carboxylate was isolated as a by-product. LCMS calc.=300.1; found=299.9 (M+Na)+. 1H NMR (500 MHz, CDCl3) a 10.07 (s, 1H); 8.21 (d, J=8.4 Hz, 1H); 7.36 (d, J=8.4 Hz, 1H); 5.06-5.00 (m, 1H); 3.93 (s, 3H); 3.19 (t, J=7.5 Hz, 2H); 2.89 (t, J=7.5 Hz, 2H); 2.08-2.02 (m, 2H); 1.32 (d, J=6.2 Hz, 6H).

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