Efficient synthesis and spectroscopy of 3,3‐dimethyl‐2,3,4,5,10,11‐hexahydro‐8‐[(o‐; and p‐methyl)phenoxy]‐11‐[(o‐; and p‐substituted)phenyl]‐1H‐dibezo‐[b,e][1,4]diazepin‐1‐ones