p-Toluenesulfonic acid → 1-(2,2-Dimethyl-1,3-dioxolan-4-yl)ethanol

To a vigorously stirring suspension of 1,2,4-butanetriol (5.8 g, 54.6 mmol) in dichloromethane (20 mL) was added 2,2-dimethoxypropane (6.8 mL, 54.6 mmol) and catalytic p-toluenesulfonic acid. After 5 minutes, the solution became homogenous and was allowed to stir for an additional 30 minutes. The reaction mixture was then concentrated in vacuo to afford (2,2-Dimethyl-[1,3]dioxolan-4-yl)-ethanol (7.72 g, 96.7%). To a stirring solution of (2,2-Dimethyl-[1,3]dioxolan-4-yl)-ethanol (6.95 g, 47.5 mmol), triphenylphosphine (12.5 g, 47.5 mmol) and N-hydroxyphthalimide in freshly distilled tetrahydrofuran (200 mL) at 0° C. was slowly added (over 20 minutes) diethylazodicarboxylate. The dark red solution was allowed to stir for 2 hours at 0° C. and then allowed to warm to room temperature while stirring for 17 hours. The yellow solution was concentrated in vacuo and dissolved in chloroform (100 mL). The solids were filtered and filtrate concentrated. This filtration was repeated twice. The remaining yellow oil was purified on silica gel eluting with hexanes-ethyl acetate (4:1) to afford 2-[2-(2,2-Dimethyl-[1,3]dioxolan-4-yl)-ethoxy]-isoindole-1,3-dione (8.1 g, 58.7%). To a stirring solution of 2-[2-(2,2-Dimethyl-[1,3]dioxolan-4-yl)-ethoxy]-isoindole-1,3-dione (0.86 g, 2.95 mmol) in dichloromethane (10 mL) at 0° C. was added methylhydrazine (0.16 mL, 2.95 mmol). The resultant solution was allowed to warm to room temperature and stirred for 3 days. The resulting suspension was diluted with diethyl ether (20 mL) and filtered. The filtrate concentrated in vacuo to afford O-(2,2-dimethyl-[1,3]dioxolan-4-ylethyl)-hydroxylamine (0.36 g, 75.3%): 1H NMR (400 MHz; CDCl3) δ 4.18 (quint, 1H, J=5.9), 4.07 (dd, 1H, J=5.9, 7.8), 3.86 (t, 2H, J=6.2), 3.56 (t, 1H, J=7.6), 1.89 (m, 2H), 1.36 (s, 3H), 1.20 (s, 3H); MS(APCI+)=162.

1. stirringto stir for an additional 30 minutes
2. concentrationThe reaction mixture was then concentrated in vacuo

ORD record

ord-27c65cbde12648b6bd6436fc8a8dc78b

Source dataset

uspto-grants-2005_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06960614B2