With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.23462-75-1,Dihydro-2H-pyran-3(4H)-one,as a common compound, the synthetic route is as follows.
23462-75-1, Cap- 177a and Cap- 177b, step a1, 1,3,3-Tetramethylguanidine (0.985 niL, 7.85 mmol) was added to a stirred solution of methyl 2-(benzyloxycarbonylamino)-2-(dimethoxyphosphoryl)acetate (2.0 g, 6.0 mmol) in EtOAc (40 mL) and the mixture was stirred at rt under 2 for 10 min. Then dihydro-2H-pyran-3(4H)-one (0.604 g, 6.04 mmol) was added and the mixture was stirred at rt for 16 h. The reaction mixture was then cooled in freezer for 10 min and neutralized with aq. citric acid (1.5 g in 20 mL water). The two phases were partitioned and the organic layer was washed with 0.25 N aq.HCl and brine, and then dried (MgS04) and concentrated to a colorless oil. The crude material was purified by flash silica chromatography (loading solvent: DCM, eluted withEtOAc/Hexanes, gradient from 20% to 30% EtOAc) to yield two isomeric products: The first eluted product was (Z)-methyl 2-(benzyloxycarbonylamino)-2-(2H-pyran- 3(4H,5H,6H)-ylidene)acetate (490 mg) (white solid), and the second was (E)-methyl 2-(benzyloxycarbonylamino)-2-(2H-pyran-3(4H,5H,6H)-ylidene)acetate (433 mg) (white solid). LC-MS retention time 1.398 min (for Z-isomer) and 1.378min (for E- isomer); m/z 304.08 (for Z-isomer) and 304.16 (for E-isomer) (MH-). LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with aPHENOMENEX Luna lOu C18 3.0x50mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 4 mL/min, a gradient of 100% Solvent A / 0% Solvent B to 0% Solvent A / 100% Solvent B, a gradient time of 3 min, a hold time of 1 min, and an analysis time of 4 min where Solvent A was 5% MeOH / 95% H2O / 10 mM ammonium acetate and Solvent B was 5%> H20 / 95%> MeOH / 10 mM ammonium acetate. MS data was determined using a MICROMASS Platform for LC in electrospray mode. ? NMR (400 MHz, chloroform-d) (for Z-isomer) delta ppm 7.30 – 7.44 (m, 5 H), 6.18 (br. s., 1 H), 5.10 – 5.17 (m, 2 H), 4.22 (s, 2 H), 3.78 (br. s., 3 H), 2.93 – 3.02 (m, 2 H), 1.80 (dt, J=l 1.7, 5.8 Hz, 2 H), 1.62 (s, 2 H). XH NMR (400 MHz, chloroform-d) (for E-isomer) delta ppm 7.31 – 7.44 (m, 5 H), 6.12 (br. s., 1 H), 5.13 – 5.17 (m, 2 H), 4.64 (br. s., 2 H), 3.70 – 3.82 (m, 5 H), 2.49 (t, J=6.5 Hz, 2 H), 1.80 (br. s., 2 H). (Note: the absolute regiochemistry was determined by XH NMR shifts and coupling constants).
The synthetic route of 23462-75-1 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; BRISTOL-MYERS SQUIBB COMPANY; BELEMA, Makonen; SRINIVASU, Pothukanuri; BENDER, John A.; LOPEZ, Omar D.; CHEN, Qi; RAMPULLA, Richard A.; GUPTA, Samayamunthula Venkata Satya Arun Kumar; MEANWELL, Nicholas A.; WO2012/21591; (2012); A1;,
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