1 CZH C2-hydroperoxy-coelenterazine 1.000 2 V1W V-coelenterazine 0.944 3 CZB (2s,8r)-8-benzyl-2-(4-bromobenzyl)-2-hydroperoxy-6-(4-hydroxyphenyl)-7,8-dihydroimidazo[1,2-a]pyrazin-3(2h)-one 0.943 4 CZI (2r)-8-benzyl-2-hydroperoxy-6-(4-hydroxyphenyl)-2-(4-iodobenzyl)-7,8-dihydroimidazo[1,2-a]pyrazin-3(2h)-one 0.943 5 CTZ C2-hydroxy-coelenterazine 0.914 6 CZP (8r)-8-(cyclopentylmethyl)-2-hydroperoxy-2-(4-hydroxybenzyl)-6-(4-hydroxyphenyl)-7,8-dihydroimidazo[1,2-a]pyrazin-3(2h) -one 0.914 7 9A3 (2s)-8-benzyl-2-hydroperoxy-6-(4-hydroxyphenyl)-2-{[4-(trifluoromethyl)phenyl]methyl}imidazo[1,2-a]pyrazin-3(2h)-one 0.868 8 CZN (2s,8r)-8-benzyl-2-hydroperoxy-6-(4-hydroxyphenyl)-2-(2-naphthylmethyl)-7,8-dihydroimidazo[1,2-a]pyrazin-3(2h)-one 0.868 9 9Z5 (4s)-8-benzyl-2-[(furan-2-yl)methyl]-3-methoxy-6-phenylimidazo[1,2-a]pyrazine 0.730