Melohemsines A-I, melodinus-type alkaloids from Melodinus hemsleyanus

Abstract

Melohemsines A-I (<bold>1–9</bold>) were obtained from <italic>Melodinus hemsleyanus</italic>. <bold>1</bold> is the first melodinus-type alkaloid possessing a 6/6/5/5/6/3 six ring skeleton system. <bold>2</bold> and <bold>3</bold> are the first natural melodinus-type alkaloids with a reduction of two carbon units at C-20.