p-Toluenesulfonic acid → 4-Methylbenzene-1-sulfonic acid--(3S)-3-aminooxetan-2-one (1/1)

Participants

Reaction Steps

BOC-L-serine β-lactone (600. mg, 3.20 mmol) and anhydrous p-toluenesulfonic acid (579 mg, 3.36 mmol) were treated with distilled CF3COOH (10 mL) at 0°-5° C. for 10 min. Removal of solvent in vacuo as above provided a white crystalline residue which was triturated with dry Et2O (20 mL) and filtered to yield (S)-3-amino-2oxetanone p-toluene sulfonic acid salt (806 mg, 97%). This material was analytically pure; however, if desired, recrystallization could be effected from DMF/Et2O (25° C.→-20° C.): mp (~4° C./min) 135° C. (darkening), 173° C. (dec. rapid); [α]D25 -15.9 (±0.1)° (c 2.2, DMF); IR 3040 (s, vbr), 1838 (vs), 1600 (w), 1585 (w), 1550 (m) cm-1 ; IR (pH 6.8, aqueous solution) 1820 cm-1 ; IR (DMF solution) 1830 cm-1 ; 1H NMR (300 MHz, d7 -DMF)δ 7.66 (d, 2H, 8.0 Hz, o-ArH), 7.15 (d, 2H, 8.0 Hz, m-ArH), 5.53 (dd, 1H, 4.6, 6.5 Hz, CH), 4.74 (m, 1H, CHHO), 4.68 (m, 1H, CHHO), 3.70 (vbr s, 3H, NH3 +), 2.31 (s, 3H, ArCH3); 13C NMR (75.5 MHz, d7-DMF) δ 165.84, 145.12, 139.14, 128.67, 126.08, 64.70, 57.45, 20.70. Anal. Calc. for C10H13NO5S: C, 46.32; H, 5.05; N, 5.04; S, 12.37. Found: C, 46.44; H, 5.14; N, 5.24; S, 12.41; POSFAB-MS (glycerol) 88 (MH+ =C3H6NO2), 180 (MH+ (gly)), 260 (MH+ (TsOH)). The enantiomeric (R)- 3-amino-2-oxetanone salt was produced in an identical manner from BOC-D-serine β-lactone prepared from BOC-D-serine.

Provenance & Evidence