Overview of the preparation of glycidyl m-nitrobenzene sulfonate from cyclopenten-1-ylboronic acid
Cyclopenten-1-ylboronic acid can be used as a pharmaceutical synthesis intermediate and an organic synthesis intermediate, and can be used in laboratory research and development processes and chemical and pharmaceutical synthesis processes.
Preparation of cyclopenten-1-ylboronic acid
Cyclopenten-1-ylboronic acid is prepared as follows:
Preparation of the raw material 1-chlorocyclopentene in the first step: Add 374.2 (1.818mol, 1.05) pentachloride into a 2L four-neck bottle equipped with a magnetic stirrer, a thermometer, a condenser tube and an exhaust alkali liquid absorption device. Phosphorus, 863g n-heptane, heat up to 70°C, add 151.4g (1.803mol, 1eq) cyclopentanone dropwise, complete the dropping in about 2 hours, continue the reaction for half an hour, cool down to 0°C, add 6mol/L hydrogen dropwise 0.69kg of sodium oxide solution, stir for one hour, separate the upper organic layer, wash the organic layer once with saturated sodium bicarbonate, and obtain 799g of n-hexane solution of 1-chlorocyclopentene, with an internal standard yield of 81.1%;
Preparation of cyclopenten-1-ylboronic acid in the second step: add T2215.5g (1.608mol, 1.1eq) into a 5L four-neck flask equipped with mechanical stirring, thermometer, argon protection device and reflux condenser ), 22.6g of metallic lithium (311 triglyceride carbonate. 216mol, 2.2eq), g of tetrahydrofuran, cool to -10°C, add dropwise the heptane solution of 1-chlorocyclopentene (1eq), and keep the temperature -10 after the dropwise addition Stir for 11 hours at The liquid flows, and the solid is precipitated. Add 200g of n-heptane to beat at -10°C, filter, and dry to obtain 89.3g of white solid cyclopenten-1-ylboronic acid, with a yield of 54.5%.
Preparation and application of cyclopenten-1-ylboronic acid
Cyclopenten-1-ylboronic acid can be used as an intermediate in pharmaceutical synthesis, such as preparing cyclohexene-1-boronic acid pinacol ester: Mix cyclopenten-1-ylboronic acid (0.640mol) and pinacol 68.1g (0.576mol, 0.9eq) was added to 300g ethyl acetate, kept at 30°C and stirred for 1 hour. The pinacol reaction was completed. After the solvent was evaporated under reduced pressure at 45°C, it was heated to 100°C and 113.2g of the product was evaporated. , yield 85.1%, GC purity 98.7%.
