An Unexpected Synthesis of Novel Oxygen-Bridged 1,5-Benzothiazepine Derivatives and their Reductive Five-Membered-Ring Opening
摘要:
A convenient procedure is reported for the preparation of benzofuro-annelated 2-phenyl-1,5-benzothiazepine derivatives by oxidative cyclocondensation of phenolic beta-diketones with o-aminothiophenol in DMSO. The regiochemistry of these compounds is proven by HMBC signals and the existence of a five-bond F-19,C-13-2 coupling. Surprisingly, treatment with LiAlH4 at room temperature led to a double reduction under opening of the five-membered ring. Refluxing such solutions with a higher amount of LiAlH4 gave rise to a further reduced derivative possessing the trans-configuration. All structures (regio- and stereochemistry) were assigned an the basis of NMR spectroscopic data.
An Unexpected Synthesis of Novel Oxygen-Bridged 1,5-Benzothiazepine Derivatives and their Reductive Five-Membered-Ring Opening
摘要:
A convenient procedure is reported for the preparation of benzofuro-annelated 2-phenyl-1,5-benzothiazepine derivatives by oxidative cyclocondensation of phenolic beta-diketones with o-aminothiophenol in DMSO. The regiochemistry of these compounds is proven by HMBC signals and the existence of a five-bond F-19,C-13-2 coupling. Surprisingly, treatment with LiAlH4 at room temperature led to a double reduction under opening of the five-membered ring. Refluxing such solutions with a higher amount of LiAlH4 gave rise to a further reduced derivative possessing the trans-configuration. All structures (regio- and stereochemistry) were assigned an the basis of NMR spectroscopic data.
A convenient procedure is reported for the preparation of benzofuro-annelated 2-phenyl-1,5-benzothiazepine derivatives by oxidative cyclocondensation of phenolic beta-diketones with o-aminothiophenol in DMSO. The regiochemistry of these compounds is proven by HMBC signals and the existence of a five-bond F-19,C-13-2 coupling. Surprisingly, treatment with LiAlH4 at room temperature led to a double reduction under opening of the five-membered ring. Refluxing such solutions with a higher amount of LiAlH4 gave rise to a further reduced derivative possessing the trans-configuration. All structures (regio- and stereochemistry) were assigned an the basis of NMR spectroscopic data.