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. 2025 Mar 18;99(6):2355–2366. doi: 10.1007/s00204-025-04018-y

Table 2.

MDMB-4CN-BUTINACA metabolites with biotransformation; molecular formulas; mean retention times; exact (calculated) masses of the protonated molecules; mass errors from all samples; peak areas after 1-, 3-, and 5-h incubations for two replicate samples; the percentage of the total peak area of metabolites across all incubations; and major fragment ions (also indicative of biotransformation)

Met # Biotransformation Formula Mean RT (min) Exact mass [M + H]+ (m/z) Average mass error (ppm) #1 peak area ( × 103) #2 peak area ( × 103) % Major fragment ions
1 h 3 h 5 h 1 h 3 h 5 h
MDMB-4CN-BUTINACA C20H26N4O3 9.33 371.2078 28.46 14,300 251 936 15,200 284 934 145.0396, 226.0975
M1 Ester hydrolysis C19H24N4O3 7.42 357.1921 10.40 10,200 11,400 12,400 10,300 11,800 12,800 78.6 145.0396, 226.0975
M2 Ester hydrolysis + dehyd C19H22N4O3 7.21 355.1765 2.30 3440 429 799 3590 489 987 11.1 145.0396, 226.0975
M3 Ester hydrolysis + monoOH (tert-butyl) C19H24N4O4 5.49 373.1870 1.03 383 775 733 380 804 829 4.5 145.0396, 226.0975
M4 Ester hydrolysis + dehyd + monoOH (tert-butyl) C19H22N4O4 6.26 371.1714 −0.77 296 306 304 302 316 345 2.1 145.0396, 226.0975
M5 Decyanation to carboxylic acid C19H25N3O5 7.78 376.1867 −0.17 356 186 100 363 212 157 1.6 87.0441, 145.0396, 231.0764
M6 Ester hydrolysis + decyanation to carboxylic acid C18H23N3O5 6.12 362.1710 −1.62 60 133 102 59 142 119 0.7 87.0441, 145.0396, 231.0764
M7 Ester hydrolysis + GLUC C25H32N4O9 5.86 533.2242 −2.13 45 94 126 42 96 130 0.6 145.0397, 226.0971
M8 Carboxylation (tert-butyl) C20H24N4O5 6.67 401.1819 −1.36 38 45 47 36 44 44 0.3 55.0542, 145.0396, 226.0975
M9 Ester hydrolysis + decyanation to alcohol C18H25N3O4 6.21 348.1918 −3.24 21 38 29 21 42 35 0.2 73.0648, 86.0964, 145.0396, 217.0972
M10 MonoOH (tert-butyl) + GLUC C26H34N4O10 5.23 563.2348 −1.59 27 32 29 30 33 25 0.2 145.0396, 226.0975
M11 Dihydrodiol (indazole) C20H28N4O5 5.73 405.2132 −2.92 31 n.d n.d 31 n.d 23 0.1 161.0346, 242.0924, 260.1030
M12 N-dealkylation + ester hydrolysis C14H17N3O3 5.71 276.1343 −2.94 n.d n.d 22 n.d 22 n.d 0.1 86.0964, 145.0396

Metabolites are ordered from most to least abundant by average peak area across all incubations

n.d. not detected