ChemicalBook CAS DataBase List (1R,2R)-1-(tert-butoxycarbonylamino)-2-(difluoromethyl)cyclopropanecarboxylic acid

(1R,2R)-1-(tert-butoxycarbonylamino)-2-(difluoromethyl)cyclopropanecarboxylic acid synthesis

6synthesis methods

Product Name:(1R,2R)-1-(tert-butoxycarbonylamino)-2-(difluoromethyl)cyclopropanecarboxylic acid
CAS Number:1152134-45-6
Molecular formula:C10H15F2NO4
Molecular Weight:251.23

Ethanamine, N-[(3,5-dichlorophenyl)methylene]-2,2-diethoxy-

1000210-73-0
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(1R,2R)-1-(tert-butoxycarbonylamino)-2-(difluoromethyl)cyclopropanecarboxylic acid

1152134-45-6
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Yield: 95%

Reaction Conditions:

Stage #1:(1R,2R)-ethyl 1-(bis(tert-butoxycarbonyl)amino)-2-(difluoromethyl)cyclopropanecarboxylate with water;lithium hydroxide in tetrahydrofuran;methanol at 20;
Stage #2: with hydrogenchloride in water; pH=3

Steps:

1.4.2
A mixture of (1R,2R)-ethyl 1-(bis(tert-butoxycarbonyl)amino)-2-(difluoromethyl)cyclopropanecarboxylate (540 mg, 1.423 mmol) in Tetrahydrofuran (7 mL) and MeOH (7.00 mL) was added 2M LiOH (3.56 mL, 7.12 mmol) in water and stirred at rt over the weekend. It was then extracted with ether, the aqueous layer was acidified with 1N HCl until pH=3. It was then extracted with ethyl acetate, dried over MgSO₄, filtered and concentrated to yield W=340 mg (95%) off-white solid. ¹HNMR (500 MHz, MeOD) δ ppm 1.39-1.54 (m, 10H,) 1.64-1.87 (m, 1H), 1.88-2.11 (m, 1H,) 5.91 (t, J=55.85 Hz, 1H).

References:

Bristol-Myers Squibb Company US2010/150866, 2010, A1 Location in patent:Page/Page column 12

259217-95-3 Synthesis