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ChemicalBook CAS DataBase List SNC 80

SNC 80 synthesis

8synthesis methods
-

Yield: 35%

Reaction Conditions:

Stage #1:N,N-diethyl-4-formylbenzamide;(-)-(2R,5S)-1-allyl-2,5-dimethylpiperazine with 1,2,3-Benzotriazole in toluene for 2 - 3 h;Heating / reflux;
Stage #2:(3-methoxyphenyl)magnesium bromide at 0 - 20; for 1.5 h;
Stage #3: with water;ammonium chloride

Steps:

3
Benzotriazole (22.3 g, 187.5 mmol), 4-formyl-N,N-diethylbenzamide (38.5 g, 187.5 mmol, from Example 1), and (2R,5S)-l-allyl-2,5-dimethylpiperazine (28.9 g, 187.5 mmol, Chirotech EPO Division of Dowpharma, The Dow Chemical Company, Cambridge, England) were added to toluene (2000 mL) in a 5 L flask with condenser and Dean-Stark trap. The reaction was heated at reflux with removal of water for 2 - 3 hours and distillation was continued to reduce the reaction volume to approximately 600 mL. The resulting mixture was cooled to room temperature, 800 mL of anhydrous tetrahydrofuran was added, and the solution was cooled to O0C. The solution was stirred at O0C during slow addition of 300 mL of 1.0 M 3- methoxyphenylmagnesium bromide (300 mmol, Aldrich Chemical). The reaction was allowed to warm to room temperature and stirring was continued for 1.5 hours. Saturated ammonium chloride solution (90 mL) was added with stirring, followed by 100 g of anhydrous magnesium sulfate. After 1 hr the suspension was filtered, washing with 300 mL of tetrahydrofuran. The filtrate was concentrated to dryness, redissolved in 2000 mL of ethyl acetate, and washed sequentially with 1 M sodium hydroxide (4 x 800 mL), water (3 x 1000 mL) and saturated sodium chloride (500 mL). The ethyl acetate solution was dried over anhydrous sodium sulfate and the solvent was removed under vacuum to give a brown oil. Ethyl acetate was added to the oil with swirling until a mobile solution was obtained. Seed crystals of the desired product were added to catalyze crystallization. The resulting crystals were collected by filtration to give 21.01 g. Subsequent concentration and crystallization of mother liquors gave two additional crops of crystals (3.70 g and 4.94 g) for a total of 29.65 g (35%) of 4-((alpha-R)-alpha-((2S,5R)- 4-allyl-2,5-dimethyl-l-piperazinyl)-3-methoxybenzyl)-N,N-diethylbenzamide.

References:

Location in patent:Page/Page column 23-24

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