With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.287193-07-1,Ethyl 4-oxotetrahydro-2H-pyran-2-carboxylate,as a common compound, the synthetic route is as follows.
To a solution of 4-oxo-tetrahydro-2H-pyran-2-carboxylic acid ethyl (0.6 g, 3.5 mmol) in absolute ethanol (6 ml) was added sulfur (0.12 g, 3.85 mmol) and tert-butyl cyanoacetate (0.64 g, 4.55 mmol). The solution was stirred under nitrogen in a 50 C. oil bath and morpholin (0.61 ml, 7.0 mmol) was added. The reaction was stirred for 18 hours and then cooled to ambient temperature and excess sulfur removed by filtration. The filtrate was concentrated in vacuo and reconstituted in ethyl acetate (50 ml). The organic phase was washed with brine (2*10 ml), dried (Na2SO4), filtered, and the solvent evaporated in vacuo. The residue was purified by silica gel chromatography using a gradient of ethyl acetate/hexane (20 to 25% gradient) as eluent. Pure fraction of the two isomers were collected and the solvent evaporated in vacuo which afforded 0.47 g of 2-amino-4,7-dihydro-5H-thieno[2,3-c]pyran-3,5-dicarboxylic acid 3-tert-butyl ester 5-ethyl ester (A) and 0.3 g of 2-amino-4,7-dihydro-5H-thieno[2,3-c]pyran-3,7-dicarboxylic acid 3-tert-butyl ester 7-ethyl ester (B) in 62% combined yield. (A)1H-NMR (300 MHz, CDCl3) delta 5.96 (bs, 2H), 4.77-4.61 (m, 2H), 4.32-4.18 (m, 3H), 3.19-3.12 (m, 1H), 2.90-2.80 (m, 1H), 1.52 (s, 9H), 1.29 (t, 3H, J=7 Hz).(B)1H-NMR (300 MHz, CDCl3) delta 5.10 (s, 1H), 4.28-4.13 (m, 3H), 3.98-3.91 (m, 1H), 2.82-2.76 (m, 2H), 1.51 (s, 9H), 1.31 (t, 3H, J=7 Hz)., 287193-07-1
As the paragraph descriping shows that 287193-07-1 is playing an increasingly important role.
Reference£º
Patent; Novo Nordisk A/S; US7019026; (2006); B1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics