Acetic Acid → Benzyl (2,2-dimethoxyethyl)[2-(4-hydroxy-2-oxo-2,3-dihydro-1,3-benzothiazol-7-yl)ethyl]carbamate

Participants

Reaction Steps

60% Aqueous dimethoxyacetaldehyde (7.0 ml, 40 mmol) was added dropwise over 1 min to a solution of 7-(2-aminoethyl)-4-hydroxy-1,3-benzothiazol-2(3H)-one hydrochloride (10.0 g, 40 mmol) in a mixture of THF (100 ml) and water (50 ml). The reaction was stirred for 30 min, AcOH (2.4 ml, 40 mmol) added, followed by sodium cyanoborohydride (5.1 g, 80 mmol) and stirred for 20 h. The mixture was quenched with water (50 ml), EtOAc (100 ml) added, followed by NaHCO3 (13.6 g, 160 mmol) and the mixture stirred for 15 min. Benzyl chloridocarbonate (6.0 ml, 40 mmol) was then added and the reaction stirred for a further 3 h. The mixture was adjusted to pH7 with 2M HCl, extracted with EtOAc (3×100 ml), washed with water and brine, dried (MgSO4), filtered and evaporated in vacuo. The residue was purified by chromatography on silica with 10% (0.1% aqNH3/MeOH)/DCM as eluant to give the sub-title compound as a colourless oil. Yield (6.0 g).

Provenance & Evidence