Preparation method of (1R, 3S)-3-aminocyclopentanolhydrochloride
A technology of aminocyclopentanol hydrochloride and cyclopentadiene, which is applied in the field of preparation of -3-aminocyclopentanol hydrochloride, can solve the problem of inability to obtain optical activity, high price of sodium periodate, and low industrialization prospects and other problems, to achieve the effect of obvious cost advantage, convenient operation and control, and high optical purity
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Embodiment 1
[0035] Preparation of (1R,3S)-3-aminocyclopentanol hydrochloride from R-mandelic acid as starting material
[0036] Step 1: Preparation of R-mandelic acid-protected hydroxylamine
[0037] Mix R-mandelic acid (21.0 g, 0.14 mol) and absolute ethanol (100 mL) in a 250 mL single-necked round-bottomed flask, then add concentrated sulfuric acid catalyst (3.0 mL); then the whole system was refluxed for 4 hours and depressurized The organic solvent was removed by rotary evaporation, and then the residue was dissolved in dichloromethane (200 mL), washed with saturated NaHCO3, brine, and dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain 23 g of a colorless oil: R - Ethyl Mandelate.
[0038] In another reaction flask, add hydroxylamine hydrochloride (19 g, 0.27 mol) and anhydrous methanol (100 mL), and then add potassium hydroxide (25 g, 0.45 mol) in methanol (80 mL) dropwise solution, a large amount of white solids were produced; filtered to remove the white soli...
Embodiment 2
[0046] Preparation of (1R,3S)-3-aminocyclopentanol hydrochloride from L-phenylalanine as starting material
[0047] Step 1: Preparation of L-phenylalanine-protected hydroxylamine
[0048] Mix L-phenylalanine (37 g, 0.14 mol) with absolute ethanol (100 mL) in a 250 mL single-necked round bottom flask, and then add SOCl 2 (25 g, 0.21 mol) was added dropwise into the reaction flask; then the whole system was refluxed for 5 hours, and the organic solvent was removed by rotary evaporation under reduced pressure to obtain L-phenylalanine ethyl ester hydrochloride. Then L-phenylalanine ethyl ester hydrochloride was mixed with sodium bicarbonate (35 g, 0.42 mol) and methanol 150 mL in the reaction flask, and di-tert-butyl dicarbonate (35 g, 0.16 mol ) into this mixture. The reaction was stirred overnight at room temperature, extracted three times with ethyl acetate, and the organic phases were combined, dried, filtered, and distilled under reduced pressure to obtain 35 g of L-Boc-ph...
Embodiment 3
[0057] Preparation of (1R,3S)-3-aminocyclopentanol hydrochloride from L-proline as starting material
[0058] Step 1: Preparation of L-proline-protected hydroxylamine
[0059] Mix L-proline (16 g, 0.14 mol) with absolute ethanol (100 mL) in a 250 mL single-necked round bottom flask, and then add SOCl 2 (25 g, 0.21 mol) was added dropwise into the reaction flask; then the whole system was refluxed for 5 hours, and the organic solvent was removed by rotary evaporation under reduced pressure to obtain L-proline ethyl ester hydrochloride. Then L-proline ethyl ester hydrochloride, sodium bicarbonate (35 g, 0.42 mol) and methanol 150 mL were mixed in the reaction flask, and di-tert-butyl dicarbonate (35 g, 0.16 mol ) into this mixture. The reaction was stirred overnight at room temperature, extracted three times with ethyl acetate, and the organic phases were combined, dried, filtered, and distilled under reduced pressure to obtain 27 g of L-Boc-proline ethyl ester, with a yield o...
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