Methanesulfonic Acid → 5-deoxy-6,6-dimethyl-D-threo-hexulose

Participants

Reaction Steps

3-hydroxy-3-methylbutanal dimethyl acetal (640 mg, 4.3 mmol) was hydrolyzed in 19 mL of H2O with CH3SO2OH (100 μL). After 4 h the hydrolysis was complete as determined by GC (50° C., 1 min to 250° C. at 15° C./ min, DB-U; tR of acetal 4.2 min, aldehyde 2.0 min). FDP-Na3 (573 mg, 1.04 mmol) was added to the solution, and the pH was adjusted to 6.5. FDP aldolase (400 units) and TPI (100 units) were added and allowed to react for 16 h. Following the same workup procedure as used in Example 1 to remove the phosphate group, the crude sugar was extracted by vigorously stirring the residue with methanol and filtering (3×50 mL). The methanol was removed under water aspirator vacuum, and the residue, 5-deoxy-6,6-dimethyl-D-threo-hexulose, having the following structure: ##STR10## was chromatographed (silica gel, water saturated ethyl acetate), yield 0.20 g (1.04 mmol, 50%): [α]25D -21.8° C. (c 0.40, H2O); 1H-NMR (200 MHz, D2O) δ 1.03, 1.20 (s, 6 H, CH3), 1.37 (dd, J=13 Hz, J=11.8 Hz, 1 H, axial H at C5), 1.83 (dd, J=13 Hz, J=4.7Hz, 1 H, equatorial H at C5), 3.15, 3.42 (d, J=11.8 Hz, 2 H, CH2OD), 3.27 (d, J=9.8 Hz, 1 H, C3), 3.91 (ddd, J=9.8 Hz, J=11.8 Hz, J=4.7 Hz, 1 H, C4); 13C-NMR (50 MHz, D2O) δ 27.14 31.11 (CH3), 43.66 (C5), 64.21, 65.82, 72.06, 75.08 (Cl, 3, 4, 6), 98.92 (C2). Anal. Calcd for C8H16O5 : C, 50.04; H, 8.4. Found: C, 50.2; H, 8.4.

Provenance & Evidence