Method for synthesizing 1,7-diazaspiro[4.5]decane with protective group
A diazaspiro and synthetic method technology, applied in the field 1, can solve the problems of difficult purification of intermediates, impossibility of large-scale production, harsh reaction conditions, etc., and achieve the effects of easy industrial operation, high yield and few reaction steps
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Embodiment 1
[0026]
[0027] 1. Synthesis of N-benzyloxycarbonyl-3-piperidine oxime
[0028]
[0029] A mixture of N-benzyloxycarbonyl-3-piperidone (259 g, 1.11 mol), hydroxylamine hydrochloride (234 g, 3.33 mol) and sodium acetate (272 g, 3.33 mol) in ethanol (2000 ml) and water (600 ml ) Stir at room temperature (10-30°C) overnight. TLC monitors the completion of the reaction. Concentrate under reduced pressure to remove ethanol. The residue is extracted with ethyl acetate, washed with water, dried, and concentrated. The crude product is obtained by column chromatography to obtain N-benzyloxycarbonyl-3 - Piperidine oxime colorless oil 146.65 g (40%).
[0030] 1 H NMR (400MHz, CDCl 3 )d ppm: δ7.258-7.362 (m, 5H), δ5.134-5.154 (m, 2H), δ4.094-4.147 (m, 2H), δ3.533-3.580 (m, 2H), δ2. 603-2.636(m, 1H), δ2.364-2.396(m, 1H), δ1.744-1.772(m, 2H).
[0031] 2.1 Synthesis of N-benzyloxycarbonyl-3-nitropiperidine:
[0032]
[0033] Urea hydroperoxide (47.3 grams, 0.6 moles) was dissol...
Embodiment 2
[0065]
[0066] Synthesis reference of N-tert-butoxycarbonyl-4-nitropiperidine Example 1 Operation steps 1 and 2.
[0067] 1. Synthesis of methyl N-tert-butoxycarbonyl-3-(3-nitropiperidin-3-yl)propionate:
[0068]
[0069] Dissolve N-tert-butoxycarbonyl-3-nitropiperidine (46 g, 0.20 mol) in tert-butanol (350 ml) and add Trition B methanol solution (32 ml) dropwise at room temperature, then add methyl acrylate (17.5 g, 0.20 mol). The reaction solution was stirred overnight at room temperature. The reaction was monitored by TLC. After the reaction was completed, tert-butanol was removed by concentration, and the residue was adjusted to weak acidity with hydrochloric acid solution. Extracted with ethyl acetate, washed with water, dried, and concentrated under reduced pressure to obtain a crude product, which was separated by column chromatography to obtain a yellow oily substance N-tert-butoxycarbonyl-3-(3-nitropiperidin-3-yl)propionic acid methyl ester 40.17 grams (63....
Embodiment 3
[0077]
[0078] Synthetic reference of N-benzyloxycarbonyl-3-nitropiperidine Example 1 Operation steps 1 and 2.
[0079] 1. Synthesis of N-benzyloxycarbonyl-3-propionyl-3-nitropiperidine
[0080]
[0081] N-benzyloxycarbonyl-3-nitropiperidine (10.99 g, 41.6 mmol) and triethylamine (0.42 g, 4.16 mmol) were dissolved in 50 ml of acetonitrile, and acrolein (3.73 g , 133 mmol) and 10 ml of acetonitrile, stirred overnight. TLC (petroleum ether / ethyl acetate=1:1) showed that the starting material disappeared and the reaction was complete. After concentration, the crude product was purified by silica gel column to obtain 6.5 g (51.1%) of N-benzyloxycarbonyl-3-propanalyl-3-nitropiperidine as a yellow oil.
[0082] 2. Synthesis of N-benzyloxycarbonyl-1,7-diazaspiro[4,5]decane
[0083]
[0084] Mix N-benzyloxycarbonyl-3-propanalyl-3-nitropiperidine (4.67 g, 15.3 mmol) and 1.0 g of Raney Ni in 25 ml of ethanol, and stir overnight at 20-25 ° C under hydrogen pressure of 30 Ps...
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