Electric Literature of 153597-59-2,Some common heterocyclic compound, 153597-59-2, name is Ethyl 6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine-2-carboxylate, molecular formula is C9H12N2O3, 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.
N-Bromosuccinimide (6.00 g, 33.7 mmol) was added portion-wise to a solution of C2 (6.00 g, 30.6 mmol) in acetonitrile (100 mL). After the reaction mixture had been stirred at 50 C for 1 hour, it was allowed to cool to room temperature, concentrated in vacuo, and partitioned between ethyl acetate (200 mL) and water (150 mL). The organic layer was washed with water (150 mL) and with saturated aqueous sodium chloride solution (100 mL), dried over magnesium sulfate, filtered, and concentrated in vacuo. Silica gel chromatography (Gradient: 20% to 80% ethyl acetate in heptane) provided material that contained residual succinimide; this was dissolved in ethyl acetate (100 mL), washed with water (2 x 100 mL) and with saturated aqueous sodium chloride solution (100 mL), dried over magnesium sulfate, filtered and concentrated under reduced pressure. The resulting yellow solid was triturated with pentane to afford the product as a white powder. Yield: 6.00 g, 21.8 mmol, 71 %. LCMS m/z 276.9 (0287) (bromine isotope pattern observed) [M+H]+. 1H NMR (400 MHz, CDCI3) delta 4.44-4.40 (m, 2H), 4.42 (q, J=7.1 Hz, 2H), 4.26 (t, J=6.2 Hz, 2H), 2.36-2.29 (m, 2H), 1 .41 (t, J=7.1 Hz, 3H).
The synthetic route of 153597-59-2 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; PFIZER INC.; CHAPPIE, Thomas Allen; PATEL, Nandini Chaturbhai; VERHOEST, Patrick Robert; HELAL, Christopher John; SCIABOLA, Simone; LACHAPELLE, Erik Alphie; WAGER, Travis T.; HAYWARD, Matthew Merrill; (127 pag.)WO2017/145013; (2017); A1;,
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