Ethanol → 2,3,8,9-Tetrahydro-5-(3,4,5-trimethoxyphenyl)-9-[(3,4,5-trimethoxyphenyl)methylene]-5H,6H-pyrano[4,3-d]thiazolo[3,2-a]pyrimidine

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Reaction Steps

A stirred solution of tetrahydro-3,5-bis[(3,4,5-trimethoxyphenyl)methylene]-4H-pyran-4-one (3.0 g, 6.5 mmole) and 2-amino-2-thiazoline (0.8 g, 7.8 mmole) in 75 ml of CHCl3 is heated at reflux for 44 hours. After cooling, the solution is filtered to remove a small amount of insoluble material. The solvent is evaporated to give an oily residue which solidifies when treated with a small amount of EtOH. The yield is 2.2 g, m.p. 166°-168°. Crystallization from 10 ml of MeCN gives 1.5 g (42%) of light yellow solid, m.p. 153°-155°. The m.p. of a sample of this material does not change when recrystallized from MeCN.

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