Preparation method of 5,5-difluoro-3-substituted piperidine derivative
A technology of derivatives and piperidine, which is applied in the field of synthesis of organic compounds, can solve problems such as inability to realize industrialized production, difficulty in product purification, and single product, and achieve the effects of avoiding difficult product separation, mild reaction conditions, and single product
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Embodiment 1
[0073] Embodiment 1: Preparation of ethyl N-benzyl-5,5-difluoro-4-hydroxyl-3-piperidinecarboxylate (3)
[0074]
[0075] 55 g of ethyl N-benzyl-5,5-difluoro-4-carbonyl-3-piperidinecarboxylate (2) was dissolved in 1 L of toluene, 10.5 g of sodium borohydride was added at room temperature, and stirred at room temperature for 72 hours under nitrogen protection. After the reaction, add 300ml of water, adjust the pH value to 8 with 1N dilute hydrochloric acid, separate the liquids, extract the aqueous phase with ethyl acetate (500ml*2), combine the organic phases, dry and concentrate with sodium sulfate, and recrystallize with ethyl acetate petroleum ether , to obtain ethyl N-benzyl-5,5-difluoro-4-hydroxy-3-piperidinecarboxylate (3) cis-trans isomerism mixture 39.6g, yield 72%.
[0076] cis-N-benzyl-5,5-difluoro-4-hydroxy-3-piperidinecarboxylic acid ethyl ester (3-1): 1 HNMR(300MHzCDCl3)δ(ppm)7.34~7.26(br,5H),4.30~4.23(br,1H),4.23~4.16(dd,2H),3.74~3.57(dd,2H),3.01~2.89(br, 4H)...
Embodiment 2
[0079] Example 2: Preparation of ethyl N-benzyl-5,5-difluoro-4-methylsulfonyloxy-3-piperidinecarboxylate (3a)
[0080]
[0081] N-benzyl-5,5-difluoro-4-hydroxy-3-piperidinecarboxylic acid ethyl ester (3) 20g was dissolved in 150ml dry tetrahydrofuran, added 16.8g triethylamine, 0.1g DMAP, cooled to 5 °C, 9.5 g of methanesulfonyl chloride was added dropwise. After the drop, the reaction liquid naturally rose to room temperature and reacted at room temperature for 15 hours. After the reaction, the reaction solution was poured into 100ml of ice water, separated, the aqueous layer was extracted with ethyl acetate (100ml*2), the organic layers were combined, dried and concentrated over sodium sulfate to obtain N-benzyl-5,5-difluoro- Ethyl 4-methylsulfonyloxy-3-piperidinecarboxylate (3a) 21 g of crude product.
Embodiment 3
[0082] Example 3: Preparation of N-benzyl-5,5-difluoro-3-ethoxycarbonyl-1,2,5,6-tetrahydropyridine (4)
[0083]
[0084] Ethyl N-benzyl-5,5-difluoro-4-methylsulfonyloxy-3-piperidinecarboxylate (3a) 21 g of the crude product was dissolved in 100 ml of dry pyridine, followed by the addition of 6.3 g of potassium tert-butoxide, nitrogen Heated to reflux under protection for 8 hours. After the reaction was cooled to room temperature, it was poured into 100ml of ice water, extracted with ethyl acetate (100ml*3), the organic layer was dried and concentrated, and the residue was purified by column chromatography (ethyl acetate / petroleum ether) to obtain N-benzyl-5, 10.2 g of 5-difluoro-3-ethoxycarbonyl-1,2,5,6-tetrahydropyridine (4), yield 65%.
[0085] 1 HNMR (300MHz CDCl 3 )δ(ppm)7.35~7.26(m,5H),6.78(s,1H),4.28~4.22(dd,2H),3.75(s,2H),3.36~3.32(m,2H),2.91~2.86( t,2H),1.33~1.29(t,3H);
[0086] MS-ESI:cal.281;found:282(M+H + ).
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More 