New discoveries in chemical research and development in 2021. Chemo-enzymatic cascade processes are invaluable due to their ability to rapidly construct high-value products from available feedstock chemicals in a one-pot relay manner. 1157938-97-0, name is 1-(2,5-Difluorophenyl)-2-(1H-1,2,4-triazol-1-yl)ethanone belongs to triazoles compound, it is a common compound, a new synthetic route is introduced below. SDS of cas: 1157938-97-0
a) Preparation of a Stock-solution of lithium-diisopropylamide (LDA) in tetrahydrofuran (THF): Diisopropylamine (716 mg, 7,1 mmol, 1.05 eq) was dissolved in anhydrous THF (21.3 mL) and the resulting solution was cooled to -78 C under a nitrogen atmosphere. Subsequently, -BuLi (2,7 M solution in w-heptane, 2.5 mL, 6.7 mmol, 1,0 eq) was added in a drop wise fashion over 15 minutes and the reaction mixture was stirred at -78 C for an additional 15 minutes. Then the solution was warmed to 0 C and stirred for 30 minutes after which the stock solution was cooled to -78 C again, b) Coupling reaction: The thus obtained LDA-solution (3,66 mL, 0.98 mmol, 1.1 eq) was transferred to a Schlenk vessel and ethylpropionate (100 mg, 0.98 mmol, 1.1 eq.) was added in a drop wise fashion at -78 C under a nitrogen atmosphere. The resulting mixture was stirred at -78 C for 30 minutes and then l-(2,5-difluorophenyl)-2-(lH-l,2,4-triazol-l-yl)ethanone (200 mg, 0.90 mmol, 1.0 eq.) in THF (3.66 mL) was added in a drop wise fashion over 15 minutes. The reaction mixture was stirred for 2 hours at -78 C and then quenched with acetic acid and warmed to room temperature. The mixture was diluted with aqueous saturated NH4C1 and ethylacetate. The aqueous layer was extracted with ethylacetate (2x) and the combined organic layers were washed with brine, dried (Na2S04), filtered and concentrated in vacuo to give a yellow oil containing the racemic ester I with a diastereomeric excess of 29% in favour of the desired RR/SS diastereomer. Further purification by column chromatography (-heptane/EtOAc/MeOH 60/40/5 v/v/v) provided the RR/SS diastereomer (light yellow solid) as well as the RS/SR diastereomer (off-white solid) in a combined overall yield of 179 mg (0.55 mmol, 61%).
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Reference:
Patent; BASILEA PHARMACEUTICA AG; VAN SUMMEREN, Ruben; VAESSEN, Harrie; MINK, Daniel; WASER, Mario; WO2014/23623; (2014); A1;,
1,2,3-Triazole – Wikipedia,
Triazoles – an overview | ScienceDirect Topics