Toluene diisocyanate manufacturer Knowledge Preparation method of di-tert-butyl azidooxalic acid_Kain Industrial Additive

Preparation method of di-tert-butyl azidooxalic acid_Kain Industrial Additive

Background and overview[1]

Di-tert-butyl azidooxalic acid can be used as a pharmaceutical synthesis intermediate. If di-tert-butylazidooxalic acid is inhaled, move the patient to fresh air; if skin contact occurs, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical attention if you feel unwell; if contact with eyes , you should separate your eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse your mouth immediately, do not induce vomiting, and seek medical attention immediately.

Preparation[1]

Di-tert-butyl azidooxalic acid is prepared as follows:

The specific steps are as follows: under ice bath conditions, drop a 50ml solution of hydrazine monohydrate (5.85g, 85%, 200mmol) into a 50ml methanol solution of BOC anhydride (48g, 220mmol) within 30 minutes, and the resulting mixed solution Stir at room temperature for 3 hours, spin dry the methanol, and add 250 ml of n-hexane. The resulting white solid is suction filtered and washed with n-hexane to obtain 19.34 g of white solid di-tert-butyl azide oxalic acid with a yield of 84%. 1H NMR (300MHz, CDCl3): δ = 6.60 (s, 2H), 1.47 (s, 9H); 13C NMR (50MHz, CDCl3) δ = 156.0, 84.1, 28.3.

Apply[1]

Di-tert-butyl azidooxalic acid can be used as a pharmaceutical synthesis intermediate. If the following reaction occurs:

The specific steps are as follows: di-tert-butyl azidooxalic acid (11.6g, 50mmol), 50ml sodium hydroxide aqueous solution (30%wt), 1,2-dichloroethane (100ml), catalytic amount of tetrabutyl Ammonium bromide (0.5g) was mixed. The mixture was heated at 55°C for 10 hours, cooled, and the organic phase was separated. The aqueous phase was extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, spin-dried to dry the solvent, and column chromatographed (petroleum) Ether: ethyl acetate = 10:1) to obtain a colorless viscous liquid (13.8 g, yield 75%). 1H NMR (300MHz, CDCl3): δ=3.53–3.97(m,8H),1.49(m,18H).

Main reference materials

[1] CN201410570945.7 A complex containing hydrazine-type nitrogen and phosphorus ligands and its application in the catalytic hydrogenation of esters. Application date 20141023, Wuhan Kaitris Technology Co., Ltd.

This article is from the Internet, does not represent the position of Toluene diisocyanate reproduced please specify the source.https://www.chemicalchem.com/archives/3097

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