Methylsempervirine chloride (11), the quaternary salt from the markedly hypotensive alkaloid sempervirine (I & Ia) on treatment with selenium yields N-methylyobyrine (111) and yobyrine (IV). On refluxing with sodium borohydride in methanol I1 furnishes methylhexahydrosempervirine in which the position of the double bond may be at &4, 15(in analogy to the formation of arecoline from methyl nicotinate) or possibly at A15. 20 (IX) or ...
