Coniine, as racemate or as pure enantiomer, paralyzes muscles when one or the other molecule blocks the nicotinic receptor on the post-synaptic membrane of the neuromuscular junction.
Subsequent studies of the racemates showed that the central stimulant activity is associated with the threo racemate and were focused on the separation and interconversion of the erythro isomer into the more active threo isomer.
In contrast to the two pure enantiomers, which have identical physical properties except for the direction of rotation of plane-polarized light, a racemate sometimes has different properties from either of the pure enantiomers.
Praziquantel is administered as a racemate, but only the ( " R " )-enantiomer is biologically active; the enantiomers may be separated using a resolution of an amine obtained from praziquantel.
The administration of the racemate results in the overall ? 1 agonism responsible for its activity . ( + )-Dobutamine also has mild ? 2 agonist activity, which makes it useful as a vasodilator.
In order to separate out the S-enantiomer of Example 20 from the racemate, Example 20 is dissolved in ethyl acetate and treated with chiral resolution reagent 1 ( " )-?-methylbenzylamine.
In the first reported example, a nine-step procedure produces the substance as a racemate ( in contrast, the naturally occurring compound is the ( + )-enantiomer; the ( " )-enantiomer does not occur naturally ).
EMA400 had an IC of 75.2 nM for rat ATR and an IC of 2.9x10 nM for rat ATR . EMA400, a racemate, was separated into EMA401, the S-enantiomer of EMA400, and EMA402, the R-enantiomer of EMA400.
In making their determinations, courts have looked at factors including : ( i ) whether the racemate was known in the prior art; ( ii ) the difficulty in resolving the enantiomer; ( iii ) the stereoselectivity of the relevant receptor; and ( iv ) other secondary considerations of non-obviousness such as commercial success, unexpected results, and satisfaction of long-felt needs in the art.
Inventors at Warner-Lambert Company LLC substituted 1, 2, 3, 4-tetrahydroisoquinoline with various functional groups to create numerous compounds of formula I that had improved affinity for ATR . EMA400, the racemate drug to EMA401, was originally Compound 6, one of the 48 compounds of formula I . Compound 6 had higher binding affinity for ATR, compared to the other 48 compounds, with an IC value of 2.8 nM in a rabbit uterus binding assay.