反应详情

The process is performed as in Example 2, starting with N-(tert-butyl)-N′-[(1S)-2-hydroxy-1-(3-nitrobenzyl)ethyl]thiourea in 80 cm3 of aqueous 6N hydrochloric acid. The heating time is 7 hours. The product is isolated in an identical manner and then purified by chromatography under an argon pressure of 80 kPa, on a column of silica gel (particle size 40-63μ; diameter 3.5 cm; height 30 cm), eluting with a dichloromethane/methanol mixture (95/5 by volume). The fractions corresponding to the expected product are collected. These fractions are combined and then concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C. 3.90 g of (−)-(4S)-4-(3-nitrobenzyl)-4,5-dihydro-1,3-thiazol-2-ylamine hydrochloride are obtained in the form of a white solid melting at 220° C. (αD20=−18.4±0.05 at a concentration of 0.5% in methanol).

1. customThe product is isolated in an identical manner
2. custompurified by chromatography under an argon pressure of 80 kPa
3. washon a column of silica gel (particle size 40-63μ; diameter 3.5 cm; height 30 cm), eluting with a dichloromethane/methanol mixture (95/5 by volume)
4. customThe fractions corresponding to the expected product are collected
5. concentrationconcentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C