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. Author manuscript; available in PMC: 2007 Oct 21.
Published in final edited form as: Drug Metab Dispos. 2005 Dec 28;34(3):483–494. doi: 10.1124/dmd.105.006643

TABLE 3. Metabolites of S-1 identified in rat urine of 0 to 24 h (using mobile phase system 1).

Numbers in bold are values of m/z for basic mass peaks in the corresponding MS spectrum.

Metabolite
Identification		 Retention
Time		 [M - H]− MS/MS Sites of Biotransformation or Confirmed Structure
 min  M/z m/z
 1* 15.56 213 111 3-(4-Fluorophenoxy)-2-hydroxy-2-methyl-propanoic acid
 2 20.87 591 415; MS3 of 415→287, 127; MS4 of 287→229, 215, 203, 197 Nitro reduction, di-methylation on N (phenylamine or amide) or hydroxyl group connected to the chiral center, mono-hydroxylation on the B-ring and glucuronidation
 3 21.66 579 403; MS3 of 403→143 Nitro reduction, di-hydroxylation on the B-ring and glucuronidation
 4 21.69 563 387; MS3 of 387→259, 245, 127 Nitro reduction, mono-hydroxylation on the B-ring and glucuronidation
 5 28.17 575 399; MS3 of 399→287, 259 203; MS4 of 287→229 Nitro reduction, di-methylation on N or O (containing H) and glucuronidation
 6 29.00 301 221; MS3 of 221→3191, 171 Mono-hydroxylation on 4-nitro-3-trifluoromethyl-phenylamine and sulfation
 7 29.18 415 287, 203, 127; MS3 of 287→229, 215, 197; MS4 of 229→172 Nitro reduction, di-methylation on N (phenylamine or amide) and/or hydroxyl group connected to the chiral center or mono-methylation with oxidation to ketone on alkyl C adjacent to the ether linkage and mono-hydroxylation on the B-ring
 8 29.44 547 435, 371, 259, 231, 201, 175; MS3 of 435→277, 231, 175; MS4 of 277→231, 171 Nitro reduction and glucuronidation
 9 30.59 467 387, 127; MS3 of 387→259, 127 Nitro reduction, mono-hydroxylation on the B-ring and sulfation
10 31.86 415 287, 259, 229, 203; MS3 of 287→244, 229, 215, 203, 189; MS4 of 229→201, 189 Nitro reduction, di-methylation on N (phenylamine or amide) and/or hydroxyl group connected to the chiral center or mono-methylation with oxidation to ketone on alkyl C adjacent to the ether linkage and mono-hydroxylation on the B-ring
11 32.30 483 403; MS3 of 403→143 Nitro reduction, di-hydroxylation on the B-ring and sulfation
12 32.43 467 387; MS3 of 387→259, 127 Nitro reduction, mono-hydroxylation on the B-ring and sulfation
13 34.65 483 403; MS3 of 403→275, 259, 221; MS4 of 275→255, 201 Nitro reduction, mono-hydroxylation on the A-ring or phenylamine on the A-ring, mono-hydroxylation on the B-ring and sulfation
14 34.90 263 221; MS3 of 221→191, 171 Mono-hydroxylation on N in the acetamide group or on the benzene ring of N-(4-nitro-3-trifluoromethyl-phenyl)-acetamide
15 35.03 343 263; MS3 of 263→221; MS4 of 221→191, 171 Mono-hydroxylation on N in the acetamide group or on the benzene ring of N-(4-nitro-3-trifluoromethyl-phenyl)-acetamide and sulfation
16 36.5 467 387; MS3 of 387→275, 255, 191, 171, 111; MS4 of 275→255, 191 Nitro reduction, mono-hydroxylation on the A-ring or phenylamine on the A-ring and sulfation
17 36.66 387 307, 275, 259, 127 Nitro reduction and mono-hydroxylation on the B-ring
18 37.20 263 221; MS3 of 221→191, 171 Mono-hydroxylation on N in the acetamide group or on the benzene ring of N-(4-nitro-3-trifluoromethyl-phenyl)-acetamide
19 38.07 513 433; MS3 of 433→307, 289, 261, 227, 205, 143 Di-hydroxylation on alkyl C adjacent to the ether linkage and the B-ring and sulfation
20 38.55 415 287, 127; MS3 of 287→259, 245, 229, 217, 203, 201; MS4 of 229→189 Nitro reduction, di-methylation on N (phenylamine or amide) and/or hydroxyl group connected to the chiral center or mono-methylation with oxidation to ketone on alkyl C adjacent to the ether linkage and mono-hydroxylation on the B-ring
21 38.69 387 259, 127; MS3 of 259→229, 201, 175 Nitro reduction and mono-hydroxylation on the B-ring
22 39 513 433; MS3 of 433→275, 204 Nitro reduction, mono-hydroxylation on the A-ring or phenylamine on the A-ring, di-hydroxylation on the B-ring with methylation on one hydroxyl group and sulfation
23 40.43 513 433; MS3 of 433→289, 261, 227, 205, 143 Di-hydroxylation on the B-ring and sulfation
24 40.91 577 401; MS3 of 401→289, 261, 205; MS4 of 261→246, 218, 204, 190 Glucuronidation of S-1
25 41.74 247 205
26 41.89 513 433; MS3 of 433→289, 275, 227, 205, 183, 143 Nitro reduction, mono-hydroxylation on the A-ring or phenylamine on the A-ring, methylation on N in amide bond, di-hydroxylation on the B-ring and sulfation
27 42.78 403 143 Nitro reduction and di-hydroxylation on the B-ring
28 43.64 385 273, 245, 225, 217, 189; MS3 of 245→225, 205, 203; MS4 of 225→205 Nitro reduction, methylation on N or O (containing H)
29 44.5 387 259, 201, 127; Nitro reduction and mono-hydroxylation on the B-ring
30 45.49 497 417; MS3 of 417→289, 205, 127; MS4 of 205→175 Mono-hydroxylation on the B-ring and sulfation
31 45.52 387 275, 255, 191, 111; MS3 of 275→255 Nitro reduction and mono-hydroxylation on the A-ring or phenylamine on the A-ring
32 46.62 371 259, 231, 111; MS3 of 259→229, 201, 175 Nitro reduction
33 47.31 385 273, 245, 225, 217, 189; MS3 of 245→225, 203 Nitro reduction, methylation on N or O (containing H)
34 47.9 563 307; MS3 of 307→289, 261, 205 Sulfation and glucuronidation of 2,3-dihydroxy-2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]-propanamide
35 51.50 417 289, 261, 205; MS3 of 289→261; MS4 of 261→246, 218, 204, 190 Mono-hydroxylation on alkyl C adjacent to the ether linkage
36 55.55 417 305, 289, 261, 205, 127; MS3 of 261→246, 218, 204, 190 Mono-hydroxylation on the B-ring
37 66.26 452 407, 289, 261; MS3 of 289→261, 244, 233, 231, 205 O-Dephenylation (the B-ring) and mercapturic acid conjugation [2-Acetylamino-3-[1-hydroxy-2-(4-nitro-3-(trifluoromethyl)phenylcarbamoyl)-propylsulfanyl]-propanoic acid]
*

indicates that the structure of the metabolite has been confirmed using a synthetic standard in LC-MSn.