Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 15801-69-1, name is 4-Bromo-1,3,5-trimethyl-1H-pyrazole, A new synthetic method of this compound is introduced below., HPLC of Formula: C6H9BrN2
Step e: preparation of (2R,4S)-4-(tert-butyl-dimethyl-silanyloxy)-2-[hydroxy-(l,3,5- trimethyl-lH-pyrazol-4-yI)-methyl]-pyrrolidine-l-carboxylic acid benzyl ester[01 15] To a solution of 4-bromo-l,3,5-trimethyl- l H-pyrazole (950 mg, 5.0 mmol) in tetrahydrofuran (25 mL) is added n-butyllithium (2.1 mL, 2.5 M in hexane) at -78C and the resulting solution is stirred for 30 minutes. A solution of (2R,4S)-4-(tert-butyl-dimethyl- silanyloxy)-2-formyl-pyrrolidine-l -carboxylic acid benzyl ester (4 mmol) in tetrahydrofuran (5 mL) is added and the reaction mixture is slowly warmed to 0C over 30 minutes, stirred for 30 minutes, and quenched with ice water (40 mL). The organic layer is separated and the aqueous layer is extracted three times with ethyl acetate (60 mL). The combined organic phases are washed with a saturated sodium chloride solution, dried over magnesium sulfate, filtered and concentrated. The crude material is purified with a silica gel column chromatography (40-100% ethyl acetate/heptanes) to provide (2R,4S)-4-(tert-butyl-dimethyl-silanyloxy)-2-[hydroxy-(l,3,5- trimethyl-lH-pyrazol-4-yl)-methyl]-pyrrolidine- l -carboxylic acid benzyl ester (280 mg, 12%) as a light yellow oil. LC-MS: 474.1 (M+l).
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.