Reference of 87661-20-9,Some common heterocyclic compound, 87661-20-9, name is tert-Butyl cyclopropanecarboxylate, molecular formula is C8H14O2, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Example 4ATert-Butyl(+/-)-1-(4-bromopentyl)cyclopropanecarboxylate 21.2 ml (52.7 mmol) of a 2.5 M solution of n-butyllithium in n-hexane were added dropwise to a solution, cooled to -78 C., of 7.4 ml (52.7 mmol) of diisopropylamine in 20 ml of abs. THF. During the addition, the reaction temperature was kept below -60 C. After 30 min of stirring at -60 C. to -70 C., this solution was added dropwise to a solution, cooled to -78 C., of 5.0 g (35.2 mmol) of tert-butyl cyclopropanecarboxylate and 16.2 g (70.3 mmol) of 1,4-dibromopentane in 20 ml of abs. THF. After the end of the addition, cooling was removed and the mixture was slowly warmed to RT with stirring. After a further 4 h of stirring at RT, the reaction mixture was added to saturated aqueous ammonium chloride solution. The mixture was extracted three times with dichloromethane. The combined organic phases were dried over magnesium sulfate and concentrated under reduced pressure. The product was purified by chromatography on silica gel (mobile phase gradient cyclohexane/dichloromethane 50:1 to 5:1). This gave, in two batches, in total 5.73 g (53.6% of theory) of the target compound.MS (DCI): m/z=308/310 (M+NH4)+.GC-MS (Method 1): Rt=4.82 min; m/z=234 (M-C4H8)+.1H-NMR (400 MHz, DMSO-d6): delta=4.29 (q, 1H), 1.78-1.71 (m, 2H), 1.67 (d, 3H), 1.65-1.43 (m, 4H), 1.39 (s, 9H), 0.98 (m, 2H), 0.67 (m, 2H).
The synthetic route of 87661-20-9 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; BAYER PHARMA AKTIENGESELLSCHAFT; US2012/28971; (2012); A1;,
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics