Optimum Performance Laminar Chromatography OPLC A new high resolution, high throughput tool in catalysis and process chemistry 1

1

1

2

3

N. Bryson , W. Amoyal , M. Manach , H. Korb , K. Ouchi 1 2 3

Bionisis SA, 18-20 Ave. Edouard Herriot, 92350 Le Plessis-Robinson, France, [email protected] Bionisis, Inc., 135 Sullivan Road, Salem, CT 06420, USA MC Medical Inc., 5-25, Nishishinjuku 7-chome, Shinjuku-ku, 160-8355 Tokyo, Japan, [email protected]

Introduction Optimum Performance Laminar Chromatography OPLCTM is a high resolution screening tool for optimization and discovery in solution phase synthetic processes. Often process development requires the analysis of a large number of reaction conditions (solvent, temperature ...). OPLC is a high-performance chromatographic technique that can analyze several samples and standards in a single run and methods are readily scaled up for micropreparative separations. This work describes 3 examples where OPLC provided a performance advantage in screening after chemical synthesis and catalysis: o for the separation of a pharmaceutically relevant diastereo-isomer o the discovery of new catalytic systems o the optimization of catalytic activity

Separation of Diastereo-isomers A chiral polycyclic ketone intermediate was reduced by hydrogenation to a pharmaceutically relevant diasteriomeric mixture of alcohols. Several different reaction conditions were tested in order to optimize the relative ratio of the desired isomer. OPLC was investigated as a tool to analyze enantiomeric purity, and as a preparative tool to recover the major isomer and confirm its conformation.

Analytical Separation 5 µl of a 5 mg/ml solution of the sample was deposited on HTSorbTM BSLA003 column (50x200 mm, Silica 60 5 µm). The desired pure diastereo-isomer was spotted alongside for comparison. The column was analyzed using a mixture of 33%EtOAc in heptane. Similar conditions were used in TLC without resolving the components (see figure). The compounds attained a distance 1/2 the column length (Rf 0.17) after 3 column volumes of solvent and the diastereo-isomers are well separated. Improved selectivity came as a result of a weaker eluting solvent and "over-run" conditions, impossible with TLC. Densitometry showed a 65:35 ratio of diastereo-isomers identical to HPLC results.

Fraction collection Fraction collection was performed to confirm the product purity/yield/conformation by loading 200 µl of a 10% solution of the diastereo-isomers (20 mg) on an HTSorb column BSLA001 20x20 Silica60 5µm column. The flowrate was increased proportionally to correspond to the increased width of the column and the elution volume was calculated to bring the samples to the exit channel (ie 7 column volumes or 28 ml).Ten fractions of 0.6 ml were collected. Only fractions 1-2 and 6-8 contained UV-active substances. Fractions 3-5 and 9-10 were void. As there was no fluorescence remaining on the plate after the run, the recovery yield was high and the column was re-used for analytical control. Only the fractions containing a UV active species were anlayzed (3 µl). Overall, with OPLC: o The method required