Table 2.
Regio- and stereospecific HB-amination of optically active 3 in HCOONH4 buffer (pH 8.5, 1 M, 0.5 mL) containing NAD+ (1 mM) at 30 °C and different enzyme concentrations (ADH/Ch1-AmDH) for 48 h
| Entry | Sub. | Con. [mM] | ADH | ADH : Ch1-AmDH [μM] | Conv.a [%] | Producta [%] | erb [%] | dr [SS: RR/RS: SR]b |
|---|---|---|---|---|---|---|---|---|
| 1 | 1S,2S-3 | 20 | Aa-ADH | 70:35 | >99 | 98 ± 1 | >99.5 : <0.5 | 1:4/0: 95c |
| 2 | 1S,2R-3 | 15 | Bs-BDHA | 50 : 50 | >99 | 95 ± 1 | >99.5 : <0.5 | 0 : 2.4/0 : 97.6c |
| 3 | 1R,2R-3 | 20 | Ls-ADH | 24 : 60 | >99 | 98 ± 1 | >99.5 : <0.5 | n.d. : >99.5/n.d. : n.d. |
| 4 | 1R,2R-3 | 20 | Ls-ADH | 35 : 70 | >99 | 99 ± 1 | >99.5 : <0.5 | n.d. : >99.5/n.d. : n.d. |
| 5 | 1R,2S-3 | 5 | Aa-ADH | 50 : 50 | 80 ± 5 | 75 ± 5 | >99.5 : <0.5 | 0: >99.5/0:0 |
a
Measured by GC-FID; the error represents experimental deviation over two independent measurements and it does not directly refer to the intrinsic instrumental detection limit that is even more accurate.
b
Measured by RP-HPLC after derivatization with a chiral reagent.
c
dr due to initial optical purity of substrate.