the latter 's alpha-hydrogen atoms were exchanged for deuteriums by treatment with d2o-meod mixture catalysed with sodium carbonate , and 2,2,4,4-tetradeuterated 3-ketone formed was reduced by sodium borodeuteride into 2,2,3,4,4-pentadeuterated pregnanediol 20-silyl ether .
C0020275
hydrogen
C0011744
deuteriums