6-BROMO-2',3',5',6'-TETRAHYDROSPIRO[INDOLINE-3,4'-PYRAN]-2-ONE

A mixture of tert-butyl 6-bromo-2-oxo-2', 3', 5', 6'-tetrahydrospiro[indoline-3, 4'-pyran]-1-carboxylate (preparation 8b, 4.20 g, 11.0 mmol) and a 5M solution of hydrogen chloride in 1, 4-dioxane (25 mL) was stirred at room temperature. A mixture of tert-butyl 6-bromo-2-oxo-2', 3', 5', 6'-tetrahydrospiro[indoline-3, 4'-pyran]-1-carboxylate (preparation 6b, 4.20 g, 11.0 mmol) and a 5M solution of hydrogen chloride in 1, 4-dioxane (25 mL) was stirred at room temperature. After 5 hours, the mixture was concentrated in vacuo to give the title compound (3.20 g, 98percent) as a pale pink solid. LRMS (m/z): 278/280 (M-1)Methyl 4-(4-bromo-2-nitrophenyl)-tetrahydro-2H-pyran-4-carboxylate A.98 (6.67 g, 19.4 mmol) was dissolved in acetic acid (97 mL), Fe powder (5.42 g, 96.97 mmol) was added and the resultant mixture was stirred at 100 n-BuLi (2M in hexane, 22.6 mL, 45.27 mmol) was added drop wise at -40°C to a solution of 6-bromo-indolin-2-one (3 g, 14.14 mmol) and diisopropylamine (6.3 mL, 45.27 mmol) in THF (60 mL). The mixture was stirred for 45 min at -40°C, 1-bromo-2-(2-bromoethoxy)ethane was added drop wise at this temperature and stirring was continued at RT for 16 h. The reaction mixture was quenched with 4N hydrogen chloride solution (40 mL) and the aqueous phase was separated and extracted with EtOAc (3x 60 mL). The combined organic layers were washed with brine (50 mL), dried over Na2S04 and concentrated. The raw product was triturated with hexane (20 mL) and filtered. The filter was washed with hexane/EtOAc = 4:1 (100 mL) affording the target compound as light brown solid. Yield: 1.2 g (31 percent). HPLC (method 1 ): Rt = 2.94 min, m/z [M+H]+ = 282.1 (MW calc. 282.13).

Molecular Weight:282.13
XLogP3:1.7
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:2
Exact Mass:281.00514
Monoisotopic Mass:281.00514
Topological Polar Surface Area:38.3
Heavy Atom Count:16
Complexity:301
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes