Synthesis and Structure of a New Semisynthetic Taraxerone Derivative Fused to a Pyrazine Ring through the C2–C3 Bond

A new semisynthetic derivative of natural taraxerone fused to a pyrazine ring through the C 2 –C 3 bond, (4a R ,6b R ,14a R ,16a S )-2,2,4a,6b,9,9,14a,16a-octamethyl-1,2,3,4,4a,5,6b,7,8,8a,9,14,14a,14b,15,16,16a,16boctadecahydrochryseno[1,2- g ]quinoxaline, has been synthesized by the Willgerodt–Kindler reaction, and its structure was determined by X-ray analysis and NMR spectroscopy.