Synthetic method for benidipine hydrochloride intermediate

A technology of a dipine intermediate and a synthesis method, applied in the direction of organic chemistry and the like, can solve the problems of waste of raw materials, few reports on the preparation method of compound A, increase the difficulty of purification, etc., and achieve the effects of high yield and simple operation.

Inactive Publication Date: 2015-04-22
天津长源医药科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] From the above route analysis, both Scheme 1 and Scheme 2 use 3-hydroxypiperidine, and 3-hydroxypiperidine itself has two alcoholic hydroxyl groups and secondary amino groups that can participate in the reaction and have similar activities, so it will generate the desired product. 3-hydroxypiperidine is relatively expensive compared to the current market price of benidipine hydrochloride raw materials, so these two routes are not the preferred route
The following three routes have their own advantages, but they all use compound A (chemical name: acetoacetic acid (1-benzyl-3-piperidinyl) ester) for synthesis, and so far, compound A's Preparation methods are rarely reported

Method used

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  • Synthetic method for benidipine hydrochloride intermediate
  • Synthetic method for benidipine hydrochloride intermediate
  • Synthetic method for benidipine hydrochloride intermediate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Preparation of 1-benzyl-3-hydroxypyridine halide:

[0031] Add methanol (10 L), 3-hydroxypyridine (1 kg) and benzyl bromide (2.15 kg) into a stirred 20 L reaction flask in sequence, heat to reflux, and complete the reaction in 3 hours, then directly concentrate under reduced pressure and distill out the methanol , washed with petroleum ether, filtered, and dried to obtain 2.73 kg of white solid.

[0032] LCMS (ESI): 186 [M-Br - ]

[0033] Add acetonitrile (150 mL), 3-hydroxypyridine (10 g) and benzyl chloride (19.9 g) to a 250 mL reaction flask in sequence, heat to reflux, and the reaction is complete in 2 hours, and directly concentrate under reduced pressure and distill out acetonitrile. Slurry and wash with petroleum ether, filter, and dry to obtain 22.6 g of white solid.

Embodiment 2

[0035] Preparation of 1-benzyl-3-piperidinol:

[0036] Add methanol (10 L) and 1-benzyl-3-hydroxypyridinium bromide (500 g) into the reaction flask, add sodium borohydride (215 g) in batches, the temperature does not exceed 25 ° C, after the addition, Heat to reflux, react for 4 hours, the reaction is complete, cool to 0~10°C, add hydrochloric acid dropwise, adjust the pH value to 8, concentrate under reduced pressure to remove the solvent, add ethyl acetate and saturated saline to dissolve, separate the liquid, and use ethyl acetate The product in the aqueous phase was extracted twice with ester, and the ethyl acetate phase was combined, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness to obtain 342.6 g of light yellow oil.

[0037] LCMS (ESI): 192 [M+H + ]

[0038] Add ethanol (1 L) and 1-benzyl-3-hydroxypyridinium chloride (50 g) to the reaction flask, add sodium borohydride (43 g) in batches, the temperature does not exceed 25 ° C, after the add...

Embodiment 3

[0040] Preparation of (1-benzyl-3-piperidinyl)acetoacetate:

[0041] Add 1-benzyl-3-piperidinol (600 g), toluene (6 L), ethyl acetoacetate (490.2 g), and boric acid (19.5 g) into a 10 L reaction flask, heat to reflux overnight, and perform HPLC Detection, 1-benzyl-3-piperidinol remaining 26.2%, add atmospheric distillation device, steam the ethanol generated by the reaction, complete the reaction in 2 hours, cool to 0~10°C, adjust the pH value to about 3, Extract the product with water (1 L×2), combine the aqueous phases, and adjust the pH value of the aqueous phase to about 7, extract with ethyl acetate (1 L×2), combine the organic phases, and wash with saturated brine (500 mL× 2) Wash, dry with anhydrous sodium sulfate, filter, and concentrate to dryness to obtain 786.1 g of yellow oil.

[0042] LCMS (ESI): 276 [M+H + ]

[0043] 1 HNMR (DMSO, 400M): δ=1.26-1.83(m,4H), 2.09-2.13(m,2H), 2.17(s,3H), 2.50-2.53(m,1H), 2.66-2.80(m, 1H), 3.56(s, 2H), 3.48(s, 2H), 4.72-4.76(m, ...

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Abstract

The invention discloses a synthetic method for a benidipine hydrochloride intermediate. The synthetic method comprises performing a nucleophilic substitution reaction on 3-hydroxypyridine and a benzyl halide under a solvent refluxing condition, so as to generate 1-benzyl-3-hydroxypyridiniumhalide; taking an alcohol as a solvent and reducing 1-benzyl-3-hydroxypyridiniumhalide to generate 1-benzyl-3-piperidinol; then performing transesterification reaction on 1-benzyl-3-piperidinol and ethyl acetoacetate under a refluxing condition by taking toluene as a solvent in the presence/absence of a catalyst, and under the condition that less than 30% of the alcohol is left, performing normal-pressure distillation until the alcohol completely finishes reaction, so as to obtain the product. The synthetic method is simple and has the three-step total yield of 80% or more, and all employed materials are industrialized products and are cheap and easily obtained, and the quality is easily controlled.

Description

technical field [0001] The invention belongs to the technical field of pharmaceutical chemical synthesis, and relates to a synthesis method of a benidipine hydrochloride intermediate. Background technique [0002] Benidipine hydrochloride, the molecular formula is C 28 h 32 ClN 3 o 6 , the chemical name is (R,R)-(+ / -)-2,6-dimethyl-4-(3-nitrobenzene)-1,4-dihydro-3,5-pyridinedicarboxylic acid- Methyl-(R)-1-benzyl-3-piperidinyl ester hydrochloride, the structural formula is as follows: [0003] [0004] Benidipine hydrochloride is a dihydropyridine calcium ion antagonist, which binds to the dihydropyridine receptor binding site and has efficient and specific inhibitory effect on calcium ion channels. Benidipine hydrochloride not only inhibits muscle-type (L-type) calcium ion channels, but also inhibits voltage-dependent N-type and T-type calcium ion channels, and is currently the only calcium ion antagonist that has effects on the above three channels agent. In additi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D211/42C07D211/90
CPCC07D211/42C07D211/90
Inventor 迟方飞应子祥刘文娟莫岚
Owner 天津长源医药科技有限公司
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