| 摘要 |
<p>1307736 Laevorotatory 6-phenyl-2,3,5,6- tetrahydroimidazo-[2,1 -b]-thiazole RHONEPOULENC SA 1 June 1970 [2 June 1969] 26411/70 Heading C2C A process for the -separation of the laevorotatory isomer of the racemic base 6-phenyl - 2,3,5,6-tetrahydroimidazo-[2,1-b] -thiazole in the form of its l-dibenzoyltartrate salt comprises reacting in solution in water or an aliphatic alcohol of 1 to 3 carbon atoms diluted by at least 10% by volume of water, the racemic 6-phenyl- 2,3,5,6 - tetrahydroimidazo - [2,1 - b] - thiazole, or a salt thereof with an optically inactive acid with a quantity of 1-dibenzoyltartaric acid or when a salt of the racemic base is used, a salt thereof, which is 0À5 to 0À7 times the amount theoretically required for complete conversion of the racemic base into the corresponding salts of 1-dibenzoyl tartaric acid with respectively the dextrorotatory and laevorotatory isomers of the base and recovering the neutral 1-dibenzoyltartrate of the 6-phenyl.2,3,5,6-tetrahydro. imidazo-[2,1-b]-thiazole by fractional crystallization from water or an aliphatic alcohol of 1 to 3 carbon atoms diluted by at least 10% by volume of water. The l-dibenzoy-ltartrate is subsequently converted to the free laevorotatory isomer of 6-phenyl-2,3,5,6-tetrahydroimidazo- [2,1=b]-thiazole by methods known per se. An example is furnished. Reference has been directed by the Comptroller to Specification 1,226,253.</p> |
