ethyl 1,4,6,7-tetrahydropyrano[4,3-c]pyrazole-3-carboxylate

Ethyl 2-oxo-2-(4-oxotetrahydro-2H-pyran-3-yl)acetate (2) (1.1 kg) was added to glacial acetic acid (1.0 kg).The temperature was controlled at 20-30 ° C, and hydrazine hydrate (910 g, 14.4 mol, 2.9 eq.) was slowly added dropwise. After the dropwise addition, the reaction was stirred overnight at this temperature.After the TLC reaction was completed, water (10 L) and ethyl acetate (5 L) were added. The pH was adjusted with solid sodium carbonate (8-9).After the adjustment, stirring for 30 min, layering. The aqueous layer was extracted with ethyl acetate (5L*2). All organic layers were combined and washed with brine (5 L).Concentrate under reduced pressure until substantially no liquid is discharged, and petroleum ether (2 L) is added for beating. filter, The white crude solid 1, 4, 6, 7-tetrahydropyrano[4, 3-c]pyrazole-3-carboxylic acid ethyl ester (3) (915 g, UPLC purity: 99percent) was obtained.Ethyl 2-oxo-2-(4-oxotetrahydro-2H-pyran-3-yl)acetate (2) (1.1 kg) was added to glacial acetic acid (1.0 kg).The temperature was controlled at 20-30 ° C, and hydrazine hydrate (910 g, 14.4 mol, 2.9 eq.) was slowly added dropwise. After the dropwise addition, the reaction was stirred overnight at this temperature.After the TLC reaction was completed, water (10 L) and ethyl acetate (5 L) were added. The pH was adjusted with solid sodium carbonate (8-9).After the adjustment, stirring for 30 min, layering. The aqueous layer was extracted with ethyl acetate (5L*2). All organic layers were combined and washed with brine (5 L).Concentrate under reduced pressure until substantially no liquid is discharged, and petroleum ether (2 L) is added for beating. filter, The white crude solid 1, 4, 6, 7-tetrahydropyrano[4, 3-c]pyrazole-3-carboxylic acid ethyl ester (3) (915 g, UPLC purity: 99percent) was obtained.

Molecular Weight:196.20
XLogP3:0.5
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:3
Exact Mass:196.08479225
Monoisotopic Mass:196.08479225
Topological Polar Surface Area:64.2
Heavy Atom Count:14
Complexity:222
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes