by use of erythro- and threo-9,10- ( 2 ) h ( 2 ) - , -12,13- ( 2 ) h ( 2 ) - and -15,16- ( 2 ) h ( 2 ) -labelled precursors , it was demonstrated that the pair of hydrogen atoms removed from each of these positions had the cis relative configuration .
C0011744
h ( 2
C0020275
hydrogen