SUPPORTING INFORMATION
Design, Synthesis and Evaluation of Fe-S Targeted
Adenosine 5’-Phosphosulfate Reductase Inhibitors
Hanumantharao Paritalaa, Yuta Suzukib, Kate S. Carrolla,*
a
Department of Chemistry, The Scripps Research Institute, Jupiter, Florida, 33458, USA
b
Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109, USA
*
Corresponding author
Address:
Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter,
Florida, 33458, USA
Email: kcarroll@scripps.edu
Phone: 561-228-2460
Fax: 561-228-2919
Synthesis of intermediates for 4a-4h and 8a-8h.
Synthesis of hydroxamates
General procedure for synthesis of hydroxamate derivatives
Bromoalkyl
carboxylates
(1
eq,
2mmol)
was
solubilized
in
7ml
of
dichloromethane and added oxalylchloride (2 eq, 4mmol) at 0oC. After five
minutes of stirring added 10µL of dimethylformamide as catalyst. The reaction
was slowly brought to rt and the reaction progress was monitored by LC/MS by
adding a small fraction of reaction mixture to ethanol and by monitoring the
formation of subsequent ethyl ester. The reaction was concentrated up on
completion and dried under high vacuum without any further purification to
remove volatile organic materials. The dried material was solubilized in 10ml of
dimethylformamide and charged with hydroxylamine hydrochloride (2eq, 2mmol)
at rt and added diisopropylethylamine (2.5 eq, 2.5mmol) at rt and continued the
reaction towards completion. The reaction was monitored on LC/MS and
quenched after the reaction making no further progress. The contents were dried
and purified using silica gel column chromatography using 20% ethylacetate in
hexane as mobile phase. c: 1H NMR (CDCl3, 400 MHz):  = 8.0 (s, 1H), 3.51 (t,
J = 6.0, 2H), 2.34 (t, J = 7.0, 2H), 2.07 (m, 3H);
13C
NMR (CDCl3, 125 MHz):  =
170.1, 32.0, 30.3, 28.5, Mass calculated for C4H8BrNO2 182.0158. Observed
(M+H) = 183.65; (M-H) = 181.21. d: 1H NMR (CDCl3, 400 MHz):  = 8.0 (s, 1H),
4.19 (s, 1H), 2.01(s, 1H).
13C
NMR (CDCl3, 125 MHz):  = 168.2, 24.5, Mass
calculated for C2H2BrNO2 153.9627. Observed (M+H) = 154.24; (M-H) = 152.76.
Synthesis of alkylthioates
Synthesis of e
1,5-dibromopentane (2eq, 3mmol) was solubilized in 10 ml of dimethylformamide
and treated with potassium thioacetate (1eq, 1.5mmol) at rt. To the stirred
suspension added sodium hydride (2eq, 2mmol) at 0 oC and allowed the reaction
to occur at 0 oC for 30 minutes and slowly brought the reaction to rt. The reaction
was monitored by LC/MS till no further progress was found. The reaction was
quenched by adding 10 ml of water to the reaction mixture and the contents were
extracted with ethyl acetate. The combined ethyl acetate fractions were
concentrated and purified using flash chromatography using 10% ethyl acetate in
hexanes. 1H NMR (CDCl3, 400 MHz):  = 3.51 (t, J = 6.8, 2H), 3.24 (t, J = 6.6,
2H), 2.34 (s, 3H), 1.83 (m, 4H), 1.29 (q, J = 6.1, 2H);
13C
NMR (CDCl3, 125
MHz):  = 193.1, 33.7, 32.4, 30.3, 29.2, 28.5, 27.2. Mass calculated for
C7H13BrOS 225.1465. Observed (M+H) = 226.52; (M-H) = 224.54.
Synthesis of f
To a well-stirred solution of the corresponding carboxylic acid (2.1 mmol),
PPh3 (2.2 mmol), and NBS (2.2 mmol) in CHCl3 (5 mL) (stirred for 10 min) was
added benzyltriethylammonium tetrathiomolybdate 1 (3 mmol) followed by
dichloroethane (1 mmol). The reaction was complete after 12 h at rt (28° C).
Diethyl ether (20 mL) was added to the reaction mixture, which was then filtered
through a Celite pad. The residue was again extracted with DCM (5 mL) followed
by extraction with diethyl ether (20 mL) and filtered again through a Celite pad.
The combined extract was evaporated and the residue was purified by column
chromatography on silica gel to give f [35].
Synthesis of alkyltriazole derivatives
General procedure for synthesis of g and h
1,4-dibromobutane (2eq, 4 mmol) was solubilized in 7ml of dimethylformamide
and added triazole (1eq, 2mmol) was and stirred for 10 minutes at rt and the
reaction mixture was cooled to 0o C and added sodium hydride (1eq, 2mmol).
The reaction was monitored till no further progress was found on LC/MS. The
reaction was quenched by adding water and by washing with saturated
ammonium chloride solution. The aqueous liquor was then extracted with ethyl
acetate and the combined ethyl acetate extracts were dried, concentrated and
purified by silica gel column using 25% ethyl acetate in hexanes as mobile
phase. g: 1H NMR (CDCl3, 400 MHz):  = 7.63 (q, J = 5.5, 2H), 4.46 (t, J = 6.8,
2H), 3.51 (t, J = 6.6, 2H), 1.82 (m, 4H),
13C
NMR (CDCl3, 125 MHz):  = 130.1,
128.1, 51.2, 33.7, 32.4, 30.2, 26.8. Mass calculated for C 6H10BrN3 204.0677.
Observed (M+H) = 205.52; (M-H) = 203.42. h: 1H NMR (CDCl3, 400 MHz):  =
8.77 (s, 1H), 8.06 (s, 1H), 4.46 (t, J = 6.8, 2H), 3.51 (t, J = 6.6, 2H), 1.82 (m, 4H).
13C
NMR (CDCl3, 125 MHz):  = 151.1, 147.2, 50.1, 33.4, 32.4, 29.2, 26.8. Mass
calculated for C6H10BrN3 204.0677. Observed (M+H) = 205.52; (M-H) = 203.12.;
(M-H) = 224.24.
Synthesis of intermediates for 13-16
Synthesis of hydroxy alkyl carboxylates
Synthesis of compound S1 (n=2 – 3). A solution of NaOH (1.2 eq) was added
to lactone (1 equiv) at rt, and it was stirred for 24 h [52]. The solution was
concentrated in vacuo, and the product was used for solid phase synthesis
without purification.
S1 (n=2): The general procedure described for the synthesis of S1 (n=2) was
followed using -butyrolactone (824 uL; 10.8 mmol) to afford 1.24 g (9.8 mmol, 91
%) of product. Rf: 0.0 (ethyl acetate). 1H NMR (DMSO-d6, 400 MHz):  = 6.22 (t,
J = 4.0, 1H), 3.39 (m, 2H), 2.02 (t, J = 6.0, 2H), 1.57 (m, 2H); ESI-LRMS calcd.
For C4H7Na2O3 (M + Na+) 149.0, found 149.0.
S1 (n=3): The general procedure described for the synthesis of S1 (n=3) was
followed using (delta)-valerolactone (1.08 g; 10.8 mmol) to afford 1.50 g (10.7
mmol, 99 %) of product. The analytical data matched previously reported
data.[52]
Synthesis of hydroxyl alkyl triazole analog moieties
Synthesis of compound S2 (n=1 – 4). To solution of alcohol (1 equiv) in CHCl3
(100 mL) was added TEA (1.2 equiv) followed by tert-butyldimethysilyl chloride
(TBMSCl) (1.1 equiv) and DMAP (0.3 equiv) at rt under Ar.[53] The reaction
mixture was stirred at rt for 10 h. The reaction mixture was then diluted with Et2O
(30 mL), washed with 10% aqueous HCl solution (3  30 mL) followed by brine
(30 mL), dried over Na2SO3, and concentrated in vacuo. The resulting residue
was purified by silica gel chromatography eluting with 3:1 hexanes/ethyl acetate
to provide the compound S2.
S2 (n=1): The general procedure described for the synthesis of S2 (n=1) was
followed using 3-bromo-1-propanol (1.50 mL, 17.2 mmol) to afford 3.70 g (14.6
mmol, 85 %) of product. Rf: 0.73 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3,
500 MHz):  = 3.73 (t, J = 5.5, 2H), 3.51 (t, J = 6.5, 2H), 2.03 (m, 2H), 0.89 (s,
9H), 0.06 (s, 6H);
13C
NMR (CDCl3, 125 MHz):  = 60.4, 35.5, 30.6, 25.9, 18.3, -
5.4.
S2 (n=2): The general procedure described for the synthesis of S2 (n=2) was
followed using 4-bromo-1-butanol (2.75 mL, 19.2 mmol) to afford 3.72 g (13.9
mmol, 73 %) of product. Rf: 0.74 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3,
500 MHz):  = 3.64 (t, J = 6.0, 2H), 3.45 (t, J = 7.0, 2H), 1.95 (m, 2H), 1.65 (m,
2H), 0.89 (s, 9H), 0.05 (s, 6H);
29.5, 25.9, 18.3, -5.3.
13C
NMR (CDCl3, 125 MHz):  = 62.1, 34.0, 31.3,
S2 (n=3): The general procedure described for the synthesis of S2 (n=3) was
followed 5-bromo-1-pentanol (1.45 mL, 12.0 mmol) to afford 2.19 g (8.62 mmol,
72 %) of product. Rf: 0.73 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3, 300
MHz):  = 3.61 (t, J = 6.3, 2H), 3.40 (t, J = 6.9, 2H), 1.87 (m, 2H), 1.50 (m, 4H),
0.89 (s, 9H), 0.04 (s, 6H).
S2 (n=4): The general procedure described for the synthesis of S2 (n=4) was
followed using 6-bromo-1-hexanol (1.51 mL, 11.0 mmol) to afford 1.92 g (6.5
mmol, 59 %) of product. The analytical data matched previously reported data
[53].
Synthesis of compound S3 (n=1 – 4). To a suspension of NaH (1.2 equiv) in
DMF (30 mL) was added 1H-1,2,3-triazole (1.1 equiv) at rt under N2, and stirred
for 1.5 h. Compound S2 (1 equiv) was added to the reaction mixture and stirred
15 h. The reaction was completed with the ratio of 1:2 product/side product due
to the nucleophilicity of 2-N on 1H-1,2,3-triazole. The reaction mixture was
concentrated in vacuo, and then diluted with EtOAc (30 mL), washed with water
(3  30 mL), and dried over Na2SO3, and concentrated in vacuo. The resulting
residue was purified by silica chromatography, eluting with 3:1 hexanes:ethyl
acetate to 1:1 hexanes:ethyl acetate, to provide the compound S3.
S3 (n=1): The general procedure described for the synthesis of S3 (n=1) was
followed using compound S2 (n=1) (3.20 g, 12.6 mmol) to afford 849 mg (3.52
mmol, 28 %) of product. Rf: 0.14 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3,
400 MHz):  = 7.69 (s, 1H), 7.57 (s, 1H), 4.51 (t, J = 7.2, 2H), 3.60 (t, J = 6.0,
2H), 2.11 (m, 2H), 0.90 (s, 9H), 0.05 (s, 6H);
13C
NMR (CDCl3, 100 MHz):  =
133.5, 123.7, 59.0, 46.7, 32.9, 25.8, 18.1, -5.5. ESI-LRMS calcd. For
C11H24N3OSi (M + H+) 242.2, found 242.1.
S3 (n=2): The general procedure described for the synthesis of S3 (n=2) was
followed using compound S2 (n=2) (3.50 g, 13.1 mmol) to afford 861 mg (26 %)
of product. Rf: 0.13 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3, 400 MHz):  =
7.65 (s, 1H), 7.53 (s, 1H), 4.39 (t, J = 7.2, 2H), 3.59 (t, J = 6.0, 2H), 1.95 (m, 2H),
1.49 (m, 2H), 0.84 (s, 9H), -0.01 (s, 6H);
13C
NMR (CDCl3, 100 MHz):  = 133.6,
123.1, 62.1, 49.9, 29.3, 27.0, 25.8, 18.2, -5.5. ESI-LRMS calcd. For
C12H25N3NaOSi (M + Na+) 278.2, found 278.1.
S3 (n=3): The general procedure described for the synthesis of S3 (n=3) was
followed using compound S1 (n=3) (2.18 g, 7.75 mmol) to afford 492 mg (25 %)
of product. Rf: 0.19 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3, 300 MHz):  =
7.66 (s, 1H), 7.52 (s, 1H), 4.36 (t, J = 7.2, 2H), 3.57 (t, J = 6.0, 2H), 1.91 (m, 2H),
1.55 (m, 2H), 1.35 (m, 2H), 0.85 (s, 9H), 0.01 (s, 6H). ESI-LRMS calcd. For
C13H28N3OSi (M + H+) 270.2, found 270.2.
S3 (n=4): The general procedure described for the synthesis of S3 (n=4) was
followed using compound S1 (n=4) (1.92 g, 6.52 mmol) to afford 655 mg (35 %)
of product. Rf: 0.11 (3:1 hexanes/ethyl acetate); 1H NMR (CDCl3, 400 MHz):  =
7.66 (s, 1H), 7.55 (s, 1H), 4.36 (t, J = 7.6, 2H), 3.56 (t, J = 6.4, 2H), 1.90 (m, 2H),
1.46 (m, 2H), 1.34 (m, 4H), 0.85 (s, 9H), 0.01 (s, 6H). ESI-LRMS calcd. For
C13H28N3OSi (M + H+) 284.2, found 284.2.
Synthesis of compound S4 (n=1 – 4). To solution of compound S3 (1 equiv) in
THF was added 1M TBAF in THF (1.3 equiv) and stirred at rt for 10 h. The
solution was concentrated in vacuo and purified by silica chromatography eluting
with 9:1 ethyl acetate/methanol to provide the compound S4.
S4 (n=1): Procedure was followed using compound S3 (n=1) (547 mg, 2.27
mmol) to afford 272 mg (2.14 mmol, 94 %) of product. Rf: 0.38 (9:1 ethyl
acetate/methanol); 1H NMR (CDCl3, 300 MHz):  = 7.61 (s, 1H), 7.60 (m, 1H),
4.48 (m, 2H), 3.57 (m, 2H), 2.07 (m, 2H);
13C
NMR (CDCl3, 100 MHz):  = 133.4,
124.0, 58.1, 46.8, 32.6. ESI-LRMS calcd. For C5H10N3O (M + H+) 128.1, found
128.1.
S4 (n=2): The general procedure described for the synthesis of S4 (n=1) was
followed using compound S3 (n=2) (834 mg, 3.37 mmol) to afford 424 mg (3.01
mmol, 95 %) of product. Rf: 0.41 (9:1 ethyl acetate/methanol); 1H NMR (DMSOd6, 400 MHz):  = 7.99 (s, 1H), 7.72 (s, 1H), 4.48 (t, J = 7.2, 2H), 3.58 (t, J = 6.8,
2H), 1.99 (m, 2H), 1.52 (m, 2H). ESI-LRMS calcd. For C6H12N3O (M + H+) 142.1,
found 142.1.
S4 (n=3): The general procedure described for the synthesis of S4 (n=3) was
followed using compound S3 (n=3) (492 mg, 1.83 mmol) to afford 270 mg (1.74
mmol, 95 %) of product. Rf: 0.34 (9:1 ethyl acetate/methanol); 1H NMR (CDCl3,
300 MHz):  = 7.69 (s, 1H), 7.55 (s, 1H) 4.40 (t, J = 7.2, 2H), 3.58 (t, J = 3.9, 2H),
1.95 (m, 2H), 1.60 (m, 2H) (m, 2H), 1.40 (m, 2H). ESI-LRMS calcd. For
C8H16N3O (M + H+) 156.1, found 156.1.
S4 (n=4): The general procedure described for the synthesis of S4 (n=4) was
followed using compound S3 (n=4) (1.92 g, 6.52 mmol) to afford 655 mg (35 %)
of product. Rf: 0.38 (9:1 ethyl acetate/methanol); 1H NMR (CDCl3, 300 MHz):  =
7.64 (s, 1H), 7.53 (s, 1H) 4.35 (t, J = 6.9, 2H), 3.58 (t, J = 6.3, 2H), 2.41 (s, 1H),
1.88 (m, 2H), 1.51 (m, 2H), 1.34 (m, 4H). ESI-LRMS calcd. For C8H16N3O (M +
H+) 170.1, found 170.1.