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

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Reaction Steps

7-(2-Aminoethyl)-4-hydroxy-1,3-benzothiazol-2(3H)-one hydrochloride (5.0 g, 20.2 mmol) was dissolved in a mixture of MeOH (50 ml) and water (25 ml), NaHCO3 (1.7 g, 20.2 mmol) added, followed by 60% aqueous dimethoxyacetaldehyde (3.5 ml, 20.2 mmol) and the mixture stirred for 20 min Sodium cyanoborohydride (91 mg, 1.6 mmol) was added and the mixture stirred for 20 h. EtOAc (125 ml) and water (75 ml) were added, followed by NaHCO3 (1.7 g, 20.2 mmol) and benzyl chloridocarbonate (3.0 ml, 20.2 mmol). The mixture was stirred for 2 h, adjusted to pH7 with 2M HCl, extracted with EtOAc (3×100 ml), washed with brine, dried (MgSO4), filtered and evaporated in vacuo. The residue was purified by chromatography on silica with 10% (0.1% aqNH3/MeOH)/DCM as eluent to give the sub-title compound as a colourless oil. Yield (6.0 g).

Provenance & Evidence