Part 3: Synthesis and biological evaluation of some analogs of the antitumor agents, 2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid, and 2-{4-[(7-bromo-2-quinolinyl)oxy]phenoxy}propionic acid

Article abstract of DOI:10.1016/j.bmc.2004.11.034

2-{4-[(7-Chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid (X469) and 2-{4-[(7-bromo-2-quinolinyl)oxy]phenoxy}propionic Acid (SH80) are among the most highly and broadly active antitumor agents to have been developed in our laboratories. However, the mecha

Full text of DOI:10.1016/j.bmc.2004.11.034

Bioorganic& Medicinal Chemistry 13 (2005) 1069–1081
Part 3: Synthesis and biological evaluation of some
analogs of the antitumor agents, 2-{4-[(7-chloro-2-quinoxalinyl)-
oxy]phenoxy}propionic acid, and 2-{4-[(7-bromo-2-quinolinyl)-
oxy]phenoxy}propionic acid
Stuart T. Hazeldine, Lisa Polin, Juiwanna Kushner, Kathryn White, Thomas H. Corbett,
Jason Biehl and Jerome P. Horwitz*
Department of Internal Medicine, Division of Hematology and Oncology, Wayne State University, School of Medicine,
Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
Received 25 October 2004; accepted 17 November 2004
Abstract—2-{4-[(7-Chloro-2-quinoxalinyl)oxy]phenoxy}propionicacid (X469) and 2-{4-[(7-bromo-2-quinolinyl)oxy]phenoxy}pro-
pionic Acid (SH80) are among the most highly and broadly active antitumor agents to have been developed in our laboratories.
However, the mechanism(s) of action of these agents remain to be elucidated, which prompted our continued endeavor to delineate
a pharmacophoric pattern, from which a putative target might be deduced. Herein, we provide additional evidence that intact qui-
noxaline and quinoline rings in XK469 and SH80, respectively, are fundamental to the activities of these structures against trans-
planted tumors in mice. The consequence of further modification of the heterocyclic ring system in XK469 and SH80, leading to
[1,8]naphthyridine; pyrrolo[1,2-a]; imidazo[1,2-a]; and imidazo[1,5-a] derivatives, all deprive the parent structures of antitumor
activity. Introduction of CH3, CF3, CH3O, CO2H, or C6H5 substituents at C4 of the quinoline ring of SH80 led to weakly active
antitumor agents. Similarly, the phenanthridine analog of SH80 manifested only modest cytotoxicity. Lastly, XK469 and SH80
are both significantly more active than the corresponding regioisomeric structures, 2-{4-[(7-halo-4-quinolinyl)oxy]phenoxy)propi-
onicacids.
ꢀ 2004 Elsevier Ltd. All rights reserved.
1. Introduction
disparate mechanisms of anticancer action have been
proposed.5a–i In the absence of a validated molecular
target, our endeavor focused on the elaboration of a
pharmacophoric pattern, from which the nature of a
putative receptor might be inferred.6
2-{4-[(7-Chloro-2-quinoxalinyl)oxy]phenoxy}propionic
acid,(XK469, 1a, Fig. 1) is among the most highly and
broadly active antitumor agents to have been developed
in our laboratories.1–4 However, the mechanism of
action of 1a remains to be established, though several,
Our initial studies7–9 indicated that changes in the nat-
ure and location of substituents in ring A of 1a effected
significant differences in both the in vitro and in vivo
activities of the 2-{4-[(substituted-2-quinoxalinyl)-
oxy]phenoxy}propionicaicds. The 7-halogeno deriva-
tives (Fig. 1, 1a–d) proved to be the most active
compounds with a relative antitumor activity of
Cl ꢀ F ꢀ Br > I. On the other hand, the 3-, 5-, 6-, and
8-regioisomers of 1a were essentially all inactive.
Replacement of the quinoxaline moiety in the lead com-
pound by either a quinazoline or a [1,2,4]-benzotriazine
ring system led, in each case, to a complete loss of anti-
tumor activity. By contrast, the quinoline analogs bear-
ing a 7-halo- or a 7-methoxy substituent (Fig. 1, 2a–e),
showed levels of antitumor activities in mice
Figure 1.
Keywords: XK469; SH80; Analogs; Antitumor.
*
Corresponding author. Tel.: +1 313 833 0715x2522; fax: +1 313 831
7518; e-mail: horwitz@kci.wayne.edu
0968-0896/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2004.11.034

1070
S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
(Br > Cl > CH3O > F ꢀ I) comparable to, or greater
than those manifested by the corresponding quinoxaline
analogs. Thus, the observed orders of activity of the 7-
halogen substituent in 1 are; Cl ꢀ F ꢀ Br > I, whereas
in 2; Br > Cl > F > I. Moreover, the R-enantiomers of
both 1 and 2 proved to be the more active of the two
antipodes.
bond in ring B of 2 was apparent from the biological
evaluation of a corresponding phenanthridine derivative
(Scheme 1, 10). Moreover, the relevance of an unsubsti-
tuted site at C4 of 2 was established by determinations of
antitumor activities as a consequence of introduction of
substituents of differing electronegativities and/or steric
requirements at this position.
In summary, the criteria established, to date, for the
antitumor activity of 1 and 2 include either a (7-halo-
2-quinoxalinoxy) or a (7-halo-2-quinolinoxyl) residue,
bridged via 1,4-hydroquinone-linkage at C2 to propionic
acid.
2. Results and discussion
2.1. Synthesis
Our syntheticapproach utilized one of two methodolo-
gies: (A) successive etherification of (R,S)-methyl 2-(4-
hydroxyphenoxy)propionate (4) with the derivatives of
2-chloroquinoxaline, followed by saponification of the
intermediate ester, or (B) reaction of selected analogs
of 2-chloroquinoline, instead with (R,S)-2-(4-hydroxy-
phenoxy)propionicacid ( 9), as previously described.7–9
However, if racemic 2-propionic acid derivatives, on
biological evaluation, manifested significant antitumor
activity, the etherification(s) was repeated with the
(R)-enantiomer.
Herein, we provide additional evidence that intact qui-
noxaline and quinoline rings in 1 and 2, respectively
are fundamental to the activities of these structures
against transplanted solid tumors in mice. Secondly, it
is established that both 2a and 2b are significantly more
active than the corresponding regioisomeric 2-{4-[(7-
halo-4-quinolinyl)oxy]phenoxy}propionicacids, that is,
structures 17a and b.
The consequence of further modification of the hetero-
cyclic rings in 1a and 2a, relative to their respective
activities, was observed from the conversions of the qui-
noxaline moiety of 1a to (a) [1,8]naphthyridine; (b) pyr-
rolo[1,2-a]; (c) imidazo[1,2-a]; and (d) imidazo[1,5-a]
derivatives. The significance of an unsubstituted C3–C4
2,7-Dichloro[1,8]naphthyridine (3), obtained in three
steps (64% overall yield) as described by Newkome
et al.10 was converted by Method A to 2-{4-[(7-
chloro[1,8]naphthyridin-2-yl)oxy]phenoxy}propionic
Scheme 1. Reagents: (a) K2CO3/CH3CN (method A); (b) aq NaOH/THF; (c) aq HCl; (d) K2CO3/DMF (method B); (e) diethyl malonate; (f) EtonÕs
reagent; (g) Me2SO4, K2CO3/acetone; (h) POCl3. *Via method A.

S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1071
acid (5). Plans to prepare either the 2,7-dichloro or 2,7-
dibromo[1,5]naphthyridine analogs of 5 were aban-
doned as a consequence of the availability of only
impractical syntheses of the desired 2,7-dihalo[1,5]naph-
thyridines.11a,b Each method led to complex mixtures of
isomericproducts, affording the desired starting materi-
als in insufficient yields to provide the isomeric propi-
onic acid derivatives in quantities deemed necessary to
conduct meaningful biological evaluations.
acetone18b gave the corresponding 4-methoxy-2-quinoli-
nols in near quantitative yield. Reaction of the mixture
with POCl3, followed by flash column chromatographic
separation of the regioisomericproducts, yielded the de-
sired intermediate, 11b. Reaction of 11b with 9 led to the
anticipated product, 2-{4-[(7-bromo-4-methoxy-2-quino-
linyl)oxy]phenoxy}propionicaicd ( 12b), but in poor
(7%) yield. The major product proved to be 7-bromo-
2-chloro-4-quinolinol. A minor improvement in yield
was observed in the reaction of 11b and 4, followed by
saponification to give the acid 12b.
4,7-Dichloropyrrolo[1,2-a]quinoxaline (6a), described
by both Guillon et al.12a and Cheesman et al.,12b was
similarly converted to 2-{4-[(7-chloropyrrolo[1,2-a]qui-
The unanticipated results of the reaction of 11b and 9
may be ascribed, in accord with an interpretation pro-
vided by Belli et al.,18c to the deactivating effect of a
CH3O substituent, meta to the reaction center (C2).
The effect is enhanced by direct conjugation of the
CH3O group with a para aza function at the one posi-
tion, with a consequent reduction of the electronegative
effect of the nitrogen. In summary, the methoxy group at
C4 deactivates the chlorine substituent at C2, and ac-
counts, thereby, for resistance of the site to nucleophilic
attack.
noxalin-4-yl)oxy]phenoxy}propionicaidc (
Scheme 1,
7a). The synthesis of 2-{4-[(7-chloroimidazo[1,2-a]quin-
oxalin-4-yl)oxy]phenoxy}propionicaidc ( 7b) likewise
proceeded from 4,7-dichloroimidazo[1,2-a]quinoxaline
(6b), which, in turn, was obtained according to Johnson
et al. and Campiani et al.13a,b
The preparation of 2-{4-[(7-chloroimidazo[1,5-a]quin-
7c) utilized
oxalin-4-yl)oxy]phenoxy}propionicaidc (
the readily accessible intermediate, 7-chloro-2(1H)qui-
noxalinone7 as starting material. Treatment of the latter
with 4-methoxybenzyl chloride in DMF in the presence
of NaH, produced the desired N-benzylated derivative,
together with the readily separable O-tautomer. Interac-
tion of the N-benzyl product with tosylmethyl isocya-
nide (TMI), according to the method described by
Barrish and Spergel,14 followed by successive removal
of the 4-methoxybenzyloxy substituent, and chlorin-
ation gave 4,7-chloroimidazo[1,5-a]quinoxaline (6c).
Etherification of the latter with 4 gave 7c.
The syntheticroute to 7-bromo-2-hcloro-4-trifluoro-
methylquinoline (11c) was based upon a procedure,
described by Hamann and co-workers,19 which is
analogous to the preparation of 6-methoxy-4-trifluo-
romethyl-2-quinolinol. Proceeding, in the present case,
from the interaction of 3-bromoaniline and ethyl
4,40,400-trifluoroacetoacetate, led to a mixture (11:1; as
determined by NMR) of 7- and 5-bromo-4-trifluoro-
methyl-2-quinolinols after cyclization. Conversion of the
mixture to the corresponding 2-chloro derivatives was
achieved in the usual manner, which was readily sepa-
rated by flash column chromatography. Conversion of
11c to 2-{4-[(7-bromo-4-trifluoromethyl-2-quinolinyl)-
oxy]phenoxy}propionicaicd ( 12c) was effected by the
standard method.
The synthesis of 3-bromo-6-chlorophenanthridine (10)
utilized the methodology developed by Badger and
Sasse15 to obtain the precursory 2-amino-4-bromobi-
phenyl. The latter was converted, on treatment with tri-
phosgene, to the corresponding isocyanate derivative.
Cyclization of the latter was effected with AlCl3 in chlo-
robenzene,16 which closely followed the procedure de-
signed for the preparation of the 3-chloro analog.
Etherification of 8 with 9, via procedure B, gave 2-{4-
[(3-bromo-6-phenanthridinyl)oxy]phenoxy}propionic
acid (10).
The introduction of a 4-carboxylic acid substituent into
7-bromo-2-chloroquinoline employed the combined
methodologies of Tokunaga et al.20a and Sadler20b to
obtain 6-bromoisatin. The latter was then converted to
7-bromocinchonic acid, as described by Wetzel et al.20c
Treatment of the cinchonic acid derivative with POCl3
provided 7-bromo-2-chloro-4-quinolinecarboxylic acid
(11d), which was transformed to 2-{4-[(7-bromo-4-carb-
oxy-2-quinolinyl)oxy]phenoxy}propionicaicd ( 12d), as
described above.
Davis and co-workers17 described a facile route to 7-
bromo-2-chloro-4-methylquinoline (11a), which was uti-
lized in the present study in a reaction with 9 for the
preparation of 2-{4-[(7-bromo-4-methyl-2-quinolinyl)-
oxy]phenoxy}propionicacid ( 12a).
7-Bromo-2-chloro-4-phenylquinoline (11e) was obtained
via the readily accessible 3-bromo-2-benzoylacetani-
lide.21 Cyclization of the latter to 7-bromo-4-phenyl-2-
quinolinol was then effected in H2SO4 (46% yield) at
100 ꢁC, without (NMR) evidence of the formation of
the corresponding 5-bromo isomer. Conversion to 11e,
and then to 2-{4-[(7-bromo-4-phenyl-2-quinolinyl)-
oxy]phenoxy}propionicaidc ( 12e) was achieved, as
described above.
The synthesis of 7-bromo-2-chloro-4-methoxyquinoline
(Scheme 1, 11b) proceeded according to the methodol-
ogy of Kappe et al.,18a who previously reported the
preparation of 7-chloro-2,4-quinolinediol. Accordingly,
3-bromoaniline (13), on treatment with ethyl malonate
gave the corresponding malondianilide (14). However,
cyclization of the latter with P2O5 in methanesulfonic
acid (EatonÕs reagent), afforded a 1:1 mixture of 5-bro-
mo (15a) and 7-bromo-2,4-quinolinediol (15b), rather
than the expected18a single isomer (15b). Treatment of
the mixture with methyl sulfate and K2CO3 in refluxing
The syntheticroute to 2-{4-[(7-bromo-4-quinolinyl)-
oxy]phenoxy}propionicacid ( 17a), the positional isomer

1072
S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
of 2a, required the intermediate, 7-bromo-4-chloroquin-
oline (16a), which has been described by Krogstad and
co-workers.22 Etherification of 16a with 9 provided
17a in good yield. Moreover, the same reaction, utilizing
the facile conversion of commercially available 4,7-
dichloroquinoline (16b) to 2-{4-[(7-chloro-4-quino-
linyl)oxy]phenoxy}propionicacid ( 17b) was performed
in equally good yield.
(2.2 log kill), but required more than twice the total
dose. However, neither the end points of toxicity nor
maximum tolerated dose (MTD) were reached with
either the R-enantiomer or the racemic mixture, to
permit a direct comparison of efficacy based upon corre-
sponding maximum tolerated doses (MTDs). Moreover,
12b failed to show in vivo activity; in fact both 12a and
12b also had higher dose requirements than 2, and as
such, are not considered as improvements in terms of
efficacy and potency (Table 2).
2.2. Cytotoxic activity and discussion
All new analogs were first evaluated, as previously de-
scribed7–9 in our in vitro disk diffusion soft agar colony
formation assay to determine cytotoxicity against leuke-
mias, solid tumors, and normal cells (see Experimental
section).
3. Conclusion
Evidence is presented to demonstrate that intact quinox-
aline and quinoline rings in 1 and 2, respectively, are
fundamental to the activities of the parent structures
against transplanted tumors in mice. Thus, modifica-
tions of the heterocyclic ring system in 1a and 2a, lead-
ing to [1,8]naphthyridine (5); pyrrolo[1,2-a] (7a);
imidazo[1,2-a] (7b); and imidazo[1,5-a] (7c) derivatives,
all deprived the parent structures of antitumor activity.
Introduction of CH3, CF3, CH3O, CO2H, or C6H5 sub-
stituents at C4 of the quinoline ring of 2a led to a group
(12a–e) of weakly active antitumor agents. Similarly, the
phenanthridine analog (10) of 2a manifested only mod-
est cytotoxicity. Lastly, 2a and 2b are both significantly
more active than the corresponding regioisomeric struc-
It was shown in our prior biological evaluations7,8 that
mouse tumors, such as Panc 03 and Colon 38, re-
sponded equally well both in vitro and in vivo to active
cytotoxic agents, such as 1a. However, the naphthyri-
dine derivative (5), which manifested interesting in vitro
activity against both Colon 38 and Panc 03 tumors, was
found to be inactive following high doses in mice bear-
ing transplanted Panc03 tumors. Neither, the C –C4,
3
five-membered, fused ring, analogs of 1, that is, 7a,b,c,
nor the phenanthridine derivative 10, manifested suffi-
cient activity (see Table 1) to warrant testing in mice.
The 7-chloro and 7-bromoquinoline derivatives, 17a
and b, with alternative placement of the oxyphenoxy
linkage at C4, that is, the regioisomericanalogs of 2a
and 2b, respectively, were similarly inactive in culture.
The majority of the C4 substituted derivatives of 2
exhibited only modest cytotoxicity and poor tumor
selectivity in culture. Thus, only the 4-methyl (12a)
and 4-methoxy (12b) derivatives of 2 showed sufficient
activities in culture to merit in vivo testing (see Table
2). Though active against Colon 38 (1.1 log kill), the
racemic form of 12a was inferior to both 1a (3.9 log kill)
and 2a (2.2 log kill). The R-enantiomer of 12a was also
active, with an efficacy of 2.0 log kill, similar to (R,S)-2a
tures, 2-{4-[(7-halo-4-quinolinyl)oxy]phenoxy}propi-
onicacids, 17a and b.
4. Experimental
All commercially available solvents and reagents were
used without further purification. Melting points were
determined on a Thomas-Hoover melting point appara-
tus and are uncorrected. Infrared spectra were measured
on a Perkin-Elmer 1330 spectrometer in KBr pellets.
Optical rotations were measured on a Jasco DIP-370
polarimeter at room temperature. Nuclear magnetic
Table 1. Cytotoxicity of XK-469 analogs against leukemic cells, solid tumor cells, and normal cells in the disk-diffusion-soft-agar-colony-formation-
assay
Compound Enantiomeric lg/disk Mouse
Mouse tumors
Human tumors
Normal cells
number
form
leukemia
L1210
Panc03 Colon 38 Mam17/Adr Colon H116 Colon H15/MDR Fibroblasts
1a
1a
Racemic
R
270
235
520
510
460
505
525
450
490
540
465
470
475
515
475
0–600
0–600
>800
>950
0–900
>850
800–900
0–950
150–400
0–500
0–500
0–150
0–350
0–50
500–600
400–600
0–600
0–200
0–350
0–50
2a
R
0–750
0–550
5
7a
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
Racemic
400–800 500–600
300–450
0
0–300
0–250
0–300
0–400
7b
7c
150–200
0–600
0–400
0–350
150–300
0–100
150–300
150–300
0–250
0–300
0
0–150
150–250
0–550
0–350
0–250
0
10
100–220
250–650
100–450
100–250
0
200–350
0–650
12a
12b
12c
12d
12e
17a
17b
0–700
0–600
300–400
450–600
200
0
0
100–250
0–250
100–300
0–200
200–400
0–200
400
0–200
0–250
0–100
150–250
0–100
0
Zone units recorded: 200 units = 6.5 mm.

S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1073
Table 2. Evaluation of selected analogs of XK-469 against solid tumors of mice
Compound Enantiomeric SC tumor Number of Total dose, Drug
IV injections mg/kg deaths loss at nadir (%)
% Body wt
T/C Log10 tumor Cures Activity
number
form
cell kill
rating
1a
1a
Racemic
Racemic
Racemic
Racemic
Racemic
R
Colon 38
Panc 03
9
5
473
300
360
1200
696
840
900
0/5
0/5
0/5
0/5
0/5
0/5
0/3
À1.7%
À15.0%
0%
0
4
3.9
3.3
2.2
0.3
1.1
2.0
0.4
2/5
1/5
0/5
0/5
0/5
0/5
0/5
++++
++++
+++
À
2a
5
Colon 38
Panc 03
6
23
68
5
12
6
0%
12a
12a
12b
Colon 38
Colon 38
Colon 38
À6.6%
À2.0%
À7.5%
+
6
7
56
+++
À
Racemic
6
For a detailed description of testing methodologies, please see Ref. 4. Treatment of Colon 38 or Panc03 began 3 days postimplant of the tumors. All
analogs were water soluble and injected iv. In the case of 12a and 12b, the injection route was switched to oral administration (po) after the second
injection due to tail vein necrosis. Only three mice were injected for 12b due to limited drug supply. Treatment was stopped when weight loss was
substantial or drug supplies were exhausted. The log kill values were based on tumors that grew (cures were excluded from calculation). The cures
represent >4.0 log kill for these tumors.
resonance (1H and 13C NMR) spectra were recorded at
room temperature, and referenced to a residual solvent
signal, on either a Varian Unity 300 or Varian Mercury
400 instruments in the Department of Chemistry,
Wayne State University, Detroit, MI. Chemical shifts
are reported in parts per million downfield from tetra-
methylsilane (TMS). The splitting pattern abbreviations
are as follows: s, singlet; d, doublet; t, triplet; q, quartet;
b, broad; m, unresolved multiplet. Mass spectra were re-
corded on a MS80RFA instrument and other instru-
ments at Wayne State University. Flash column
chromatography was carried out with silica gel 200–
was complete. After it was cooled, the reaction mixture
was concentrated, water was then added, and the solu-
tion was filtered through Celite to remove insoluble
material. After it was cooled, the filtrate was acidified
with 1 M HCl to pH 3–4, and the solid was collected,
washed with ice-water, and dried or extracted with
AcOEt. The impure product was dissolved in AcOEt
and filtered through silica gel to remove the dark, very
polar contaminant. The filtrate was then concentrated,
purified by flash column chromatography (if required),
and crystallized.
˚
400 mesh, 60 A (Aldrich), and the crude product was
4.4. 2-{4-[(7-Chloro[1,8]naphthyridin-2-yl)oxy]phen-
oxy}propionic acid (5)
introduced on to the column as a CHCl3 solution.
Thin-layer chromatography was performed on What-
man PE SIL G/UV (250 lm) plates. Compounds were
visualized by use of 254 or 366 nm light and I2 vapor.
Elemental analyses were performed by M-H-W Labora-
tories, Phoenix, AZ.
The methyl ester of 5 was prepared by refluxing over-
night a mixture of 3 (0.40 g, 2.0 mmol), 4 (0.43 g,
2.2 mmol), anhydrous K2CO3 (0.36 g, 2.6 mmol), and
CH3CN (20 mL). Pure material (0.47 g, 66% yield) was
obtained after chromatography (2:1 hexanes–AcOEt)
and recrystallization from AcOEt–hexanes to give white
4.1. General method of the preparation of esters (proce-
dure A)
1
crystals. Mp 94–96 ꢁC; H NMR (400 MHz, CDCl3): d
8.11 (d, J = 8.0 Hz, 1H), 8.03 (d, J = 8.4 Hz, 1H), 7.32
(d, J = 8.8 Hz, 1H), 7.18 (d, J = 8.8 Hz, 1H), 7.17–7.12
(m, 2H), 6.92–6.86 (m, 2H), 4.73 (q, J = 6.4 Hz, 1H),
3.77 (s, 3H), 1.62 (d, J = 7.2 Hz, 3H). 13C NMR
(100 MHz, CDCl3): d 172.9, 165.4, 155.2, 154.7, 154.0,
147.2, 139.9, 139.1, 123.0, 121.8, 118.8, 116.4, 114.7,
73.4, 52.7, 18.9. IR (KBr) 1750 (C@O) cmÀ1. MS (EI)
m/z (%) 358 (M+, 100), 299 (93), 271 (89), 255 (14),
243 (10), 192 (6), 163 (60), 149 (8), 136 (10), 127 (15),
100 (8), 91 (35), 76 (6), 63 (11), 59 (8), 55 (6), 50 (5).
HRMS (EI) m/z 358.0722 (calcd for C18H15N2ClO4
358.0720). Anal. (C18H15N2ClO4) C, H, N.
A mixture of the 2(4)-chloroheterocycle, 4, anhydrous
K2CO3, and an aproticsolvent (CH CN) was refluxed
3
until the reaction was complete. The hot mixture was fil-
tered, the residue was washed with warm acetone, and
the filtrate was evaporated to dryness. The crude residue
was purified by flash column chromatography, where re-
quired, followed by crystallization.
4.2. General procedure for the hydrolysis of esters
To a solution of the ester dissolved in tetrahydrofuran
(THF), was added, in portions, 0.1 M NaOH and the
mixture was stirred overnight at room temperature.
The reaction mixture was concentrated, filtered to re-
move insoluble material, and then cooled and adjusted
to pH 3–4 with 0.25 M HCl. The solid that deposited
on further cooling was collected, washed with ice-water,
dried, and crystallized.
The methyl ester of 5 (0.43 g, 1.2 mmol), dissolved in
THF (25 mL), was hydrolyzed with 0.1 M NaOH
(25 mL, 2.5 mmol) to give 5 (0.42 g, ꢁ100%) as white
crystals
after
recrystallization
from
CHCl3.
1
Mp ꢁ 120 ꢁC (dec); H NMR (400 MHz, DMSO-d6): d
13.04 (br s, 1H), 8.49 (d, J = 9.2 Hz, 1H), 8.44 (d,
J = 8.0 Hz, 1H), 7.55 (d, J = 8.0 Hz, 1H), 7.38 (d,
J = 8.8 Hz, 1H), 7.20–7.14 (m, 2H), 6.98–6.92 (m, 2H),
4.84 (q, J = 6.8 Hz, 1H), 1.52 (d, J = 7.2 Hz, 3H). 13C
NMR (100 MHz, DMSO-d6): d 173.8, 165.6, 155.5,
154.3, 153.0, 146.9, 141.7, 141.1, 123.5, 122.0, 119.5,
116.3, 114.8, 72.6, 19.0. IR (KBr) 3420 (OH), 1715
4.3. General direct method for the preparation of acids
(procedure B)
A mixture of the 2(4)(6)-chloroheterocycle, 9, anhydrous
K2CO3, and DMF was gently refluxed until the reaction

1074
S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
(C@O) cmÀ1. MS (EI positive ion) m/z (%) 727(2M+K)
J = 2.4 Hz, 1H), 6.76 (dd, J = 8.4, 2.0 Hz, 1H), 3.89
(br s, 2H).
(15), 711(2M+Na) (26), 706(2M+NH ) (15), 689(2M+H) (54),
4
383(M+K) (18), 367(M+Na) (55), 362(2M+NH ) (11),
4
345(M+H) (100). Anal. (C17H13N2ClO4) C, H, N.
4.7. 7-Chloro-4-imidazo[1,2-a]quinoxalinol
A
mixture 1-(2-amino-4-chlorophenyl)-1H-imidazole
4.5. 2-{4-[(7-Chloro-4-pyrrolo[1,2-a]quinoxalinyl)-
oxy]phenoxy}propionic acid (7a)
(ꢁ14 mmol) and 1,10-carbonyldiimidazole (2.27 g,
14.0 mmol) in 1,2-Cl2Ph (100 mL) was heated at reflux
for 1.5 h. After cooling the solid was filtered, washed
with acetone, and dried to give (2.21 g, 72% yield) as a
The methyl ester of 7a was prepared by refluxing over-
night a mixture of 6a (0.47 g, 2.0 mmol), 4 (0.43 g,
2.2 mmol), anhydrous K2CO3 (0.36 g, 2.6 mmol), and
CH3CN (10 mL). Pure material (0.65 g, 82% yield) was
obtained after chromatography (4:1 hexanes–AcOEt)
and recrystallization from EtOH to give off-white crys-
1
brown solid. H NMR (400 MHz, DMSO-d6): d 11.91
(s, 1H), 8.51 (s, 1H), 8.10 (d, J = 9.2 Hz, 1H), 7.58 (d,
J = 1.6 Hz, 1H), 7.35 (d, J = 1.6 Hz, 1H), 7.32 (dd,
J = 8.4, 2.0 Hz, 1H).
1
tals. Mp 123–125 ꢁC; H NMR (400 MHz, CDCl3): d
4.8. 4,7-Dichloroimidazo[1,2-a]quinoxaline (6b)
7.86–7.83 (m, 1H), 7.68 (d, J = 8.8 Hz, 1H), 7.61 (d,
J = 2.4 Hz, 1H), 7.31 (dd, J = 8.8, 2.4 Hz, 1H), 7.25–
7.19 (m, 2H), 7.19–7.15 (m, 1H), 6.98–6.92 (m, 2H),
6.86–6.83 (m, 1H), 4.79 (q, J = 6.8 Hz, 1H), 3.80 (s,
3H), 1.66 (d, J = 6.4 Hz, 3H). 13C NMR (100 MHz,
CDCl3): d 172.9, 156.1, 155.1, 146.8, 136.1, 130.5,
128.1, 125.8, 125.6, 123.2, 119.2, 116.1, 115.8, 114.7,
114.0, 106.8, 73.4, 52.7, 18.9. IR (KBr) 1730 (C@O)
cmÀ1. MS (EI) m/z (%) 396 (M+, 100), 337 (32), 309
(92), 293 (14), 274 (5), 255 (5), 218 (5), 201 (50), 174
(15), 169 (9), 166 (9), 149 (7), 139 (5), 75 (5), 63 (6), 59
(7). Anal. (C21H17N2ClO4) C, H, N.
A
mixture of 7-chloro-4-imidazo[1,2-a]quinoxalinol
(2.19 g, 9.97 mmol), POCl3 (9.2 mL, 15 g, 100 mmol),
and PCl5 (4.4 g, 20 mmol) was refluxed overnight. After
cooling it was concentrated to give a brown semi-solid,
which was added to water and NaHCO3 added slowly
until pH 7. The mixture was filtered, washed with water,
and dried to give a yellow solid. This was heated with
AcOEt, the insoluble material filtered off, and the filtrate
concentrated to give (2.15 g, 91% yield) as a yellow solid.
Mp 227–229 ꢁC; 1H NMR (400 MHz, CDCl3): d 8.15 (s,
1H), 8.03 (d, J = 2.4 Hz, 1H), 7.85 (s, 1H), 7.83 (d,
J = 8.8 Hz, 1H), 7.64 (dd, J = 8.8, 2.4 Hz, 1H).
The methyl ester of 7a (0.44 g, 1.1 mmol), dissolved in
THF (20 mL), was hydrolyzed with 0.1 M NaOH
(22 mL, 2.2 mmol) to give 7a (0.41 g, 97% yield) as pale
yellow crystals after recrystallization from CHCl3. Mp
4.9. 2-{4-[(7-Chloro-4-imidazo[1,2-a]quinoxalinyl)-
oxy]phenoxy}propionic acid (7b)
1
184–185 ꢁC; H NMR (400 MHz, DMSO-d6): d 13.08
The methyl ester of 7b was prepared by refluxing for 4 h
a mixture of 6b (0.47 g, 2.0 mmol), 4 (0.41 g, 2.1 mmol),
anhydrous K2CO3 (0.36 g, 2.6 mmol), and CH3CN
(10 mL). Pure material (0.63 g, 79% yield) was obtained
after chromatography (4:1 hexanes–AcOEt) and recrys-
tallization from AcOEt to give off-white crystals. Mp
186–188 ꢁC; 1H NMR (400 MHz, CDCl3): d 8.08 (s,
1H), 7.79 (s, 1H), 7.76–7.22 (m, 2H), 7.44 (dd, J = 9.2,
1.6 Hz, 1H), 7.29–7.23 (m, 2H), 6.98–6.92 (m, 2H),
4.79 (q, J = 6.8 Hz, 1H), 3.80 (s, 3H), 1.65 (d,
J = 7.6 Hz, 3H). 13C NMR (100 MHz, CDCl3): d
172.9, 155.4, 153.5, 146.6, 135.6, 134.3, 132.7, 132.3,
128.5, 126.8, 125.1, 123.2, 116.0, 115.8, 114.1, 73.3,
52.7, 18.9. IR (KBr) 1740 (C@O) cmÀ1. MS (EI) m/z
(%) 397 (M+, 100), 368 (5), 338 (60), 310 (69), 294 (9),
283 (18), 256 (6), 236 (9), 220 (6), 202 (25), 167 (9),
152 (7), 137 (7), 129 (12), 125 (7), 123 (8), 115 (7), 111
(13), 109 (10), 100 (8), 97 (26), 95 (19), 91 (12), 83
(35), 81 (27), 73 (27), 71 (28), 69 (57), 67 (24), 63 (12),
60 (23), 57 (58), 55 (67). Anal. (C20H16N3ClO4) C, H, N.
(br s, 1H), 8.48–8.45 (m, 1H), 8.24 (d, J = 8.8 Hz, 1H),
7.51 (d, J = 2.8 Hz, 1H), 7.47 (dd, J = 8.8, 2.4 Hz, 1H),
7.26–7.20 (m, 2H), 7.09 (d, J = 4.0 Hz, 1H), 6.96–6.90
(m, 3H), 4.83 (q, J = 6.8 Hz, 1H), 1.52 (d, J = 6.4 Hz,
3H). 13C NMR (100 MHz, DMSO-d6): d 173.9, 156.2,
155.5, 146.4, 135.9, 129.9, 127.2, 126.2, 125.9, 123.6,
118.6, 118.4, 116.8, 116.0, 114.6, 107.2, 72.6, 19.0. IR
(KBr) 3420 (OH), 1705 (C@O) cmÀ1. MS (EI) m/z (%)
382 (M+, 81), 337 (9), 323 (6), 309 (100), 293 (8), 274
(9), 218 (6), 201 (63), 174 (21), 168 (7), 166 (13), 149
(10), 139 (7), 83 (5), 81 (5), 75 (7), 69 (8), 63 (9), 57
(9), 55 (10), 50 (5), 45 (6). HRMS (EI) m/z 382.0724
(M+, calcd for C20H15N2ClO4 382.0720). Anal.
(C20H15N2ClO4) H, N; C: calcd, 62.75; found 61.39.
4.6. 1-(2-Amino-4-chlorophenyl)-1H-imidazole
To a solution of NH4Cl (1.50 g, 28.0 mmol) in water
1-(4-chloro-2-nitrophenyl)-1H-imidazole13
(15 mL),
(3.13 g, 14.0 mmol) in EtOH (50 mL) was added, fol-
lowed by zincdust (9.34 g, 140 mmol) and the mixture
stirred overnight. The zincwas filtered off, washing with
hot EtOH, and the filtrate concentrated to give a dark
solid. This was mixed with AcOEt and anhydrous
MgSO4 added before filtering off the insoluble material.
The filtrate was concentrated to give (ꢁ100% crude
The methyl ester of 7b (0.58 g, 1.5 mmol), dissolved in
THF (40 mL), was hydrolyzed with 0.1 M NaOH
(29 mL, 2.9 mmol) to give 7b (0.50 g, 89% yield) as white
crystals after recrystallization from EtOH. Mp 244–
1
246 ꢁC; H NMR (400 MHz, DMSO-d6): d 13.08 (br s,
1H), 8.81 (s, 1H), 8.30 (d, J = 8.8 Hz, 1H), 7.81 (s,
1H), 7.64 (d, J = 2.4 Hz, 1H), 7.59 (dd, J = 9.2, 2.4 Hz,
1H), 7.31–7.25 (m, 2H), 6.99–6.92 (m, 2H), 4.85 (q,
J = 6.8 Hz, 1H), 1.53 (d, J = 6.4 Hz, 3H). 13C NMR
1
yield) as a brown solid. H NMR (400 MHz, CDCl3):
d 7.85 (s, 1H), 7.31 (d, J = 1.6 Hz, 1H), 7.14 (t,
J = 1.6 Hz, 1H), 7.01 (d, J = 8.0 Hz, 1H), 6.84 (d,

S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1075
(100 MHz, DMSO-d6): d 173.9, 155.6, 153.7, 146.2,
4.12. 7-Chloro-4-imidazo[1,5-a]quinoxalinol
135.2, 134.3, 132.1, 131.3, 127.3, 126.9, 125.7, 123.5,
117.9, 116.7, 116.1, 72.5, 19.0. IR (KBr) 3430 (OH),
1705 (C@O) cmÀ1. MS (EI) m/z (%) 383 (M+, 15), 339
(31), 324 (100), 310 (90), 295 (16), 283 (36), 254 (5),
220 (8), 202 (38), 191 (10), 175 (8), 167 (12), 150 (7),
148 (7), 136 (11), 124 (11), 115 (6), 110 (9), 105 (6),
100 (8), 91 (14), 81 (10), 77 (9), 75 (10), 69 (8), 65 (11),
63 (21), 57 (7), 55 (10), 53 (11), 51 (10), 45 (10). HRMS
(EI) m/z 383.0672 (M+, calcd for C19H14N3ClO4
383.0681). Anal. (C19H14N3ClO4) C, H, N.
To solution of 7-chloro-5-(4-methoxybenzyl)-4(5H)-imi-
dazo[1,5-a]quinoxalinone (0.91 g, 2.7 mmol) in TFA
(15 mL) and anisole (6 mL), TfOH (3 mL) was added
slowly and the mixture stirred overnight at room tem-
perature. The mixture was concentrated to give a red li-
quid, which was slowly poured into a mixture of
saturated NaHCO3 (25 mL) and AcOEt (25 mL). After
mixing it was filtered, washed with water and AcOEt,
and dried to give (0.50 g, 85% yield) as a tan solid.
1
Mp >300 ꢁC; H NMR (400 MHz, DMSO-d6): d 11.49
(s, 1H), 9.04 (s, 1H), 8.19 (d, J = 9.2 Hz, 1H), 7.85 (s,
1H), 7.38–7.25 (m, 2H).
4.10. 1-(4-Methoxybenzyl)-2(1H)-7-chloroquinoxalinone
and 7-chloro-2-(4-methoxybenzyloxy)quinoxaline
4.13. 4,7-Dichloroimidazo[1,5-a]quinoxaline (6c)
To
a
mixture of 7-chloro-2-quinolinone7 (0.89 g,
4.9 mmol) in anhydrous DMF at 0 ꢁC, 60% NaH
(0.30 g, 7.5 mmol) was added slowly. After 0.5 h, 4-
methoxybenzyl chloride (0.70 mL, 0.81 g, 5.1 mmol)
was added and the mixture stirred at room temperature
overnight. This was concentrated to give a brown-yellow
solid, which was mixed with water (25 mL) and ex-
tracted with AcOEt (2 · 50 mL). The combined extracts
were washed with saturated NaCl (10 mL), dried over
anhydrous MgSO4 and concentrated to give a yellow
semi-solid. The regioisomers were separated utilizing
column chromatography using 2:1 hexanes–AcOEt as
the eluent. The O-substituted product eluted first and
was recrystallized using hexanes to give (0.24 g, 16%
yield) as yellow crystals. Mp 86–88 ꢁC; 1H NMR
(400 MHz, CDCl3): d 8.45 (s, 1H), 7.92 (d, J = 8.0 Hz,
1H), 7.85 (d, J = 2.4 Hz, 1H), 7.49 (dd, J = 8.8, 2.4 Hz,
1H), 7.48–7.43 (m, 2H), 6.96–6.91 (m, 2H), 5.45 (s,
2H), 3.82 (s, 3H). 13C NMR (100 MHz, CDCl3): d
160.0, 157.8, 141.1, 140.2, 137.6, 136.1, 130.7, 130.3,
128.2, 127.6, 126.6, 114.2, 68.5, 55.5. The N-substituted
product eluted next and was recrystallized using AcOEt–
hexanes to give (0.86 g, 58% yield) as white crystals. Mp
149–150 ꢁC; 1H NMR (400 MHz, CDCl3): d 8.35 (s,
1H), 7.79 (d, J = 8.8 Hz, 1H), 7.32 (d, J = 1.6 Hz, 1H),
7.26 (dd, J = 8.0, 2.4 Hz, 1H), 7.23–7.18 (m, 2H),
6.88–6.83 (m, 2H), 5.36 (s, 2H), 3.77 (s, 3H). 13C
NMR (100 MHz, CDCl3): d 159.5, 155.1, 150.5, 137.3,
133.7, 132.4, 131.9, 128.7, 126.7, 124.5, 114.8, 114.7,
A
mixture of 7-chloro-4-imidazo[1,5-a]quinoxalinol
(0.49 g, 2.2 mmol) and POCl3 (2.0 mL, 3.4 g, 22 mmol)
was refluxed overnight. After cooling it was concen-
trated to give a brown solid, which was added to water
and NaHCO3 added slowly until pH 7. The mixture was
filtered, washed with water, and dried to give a brown
solid. This was heated with AcOEt, the insoluble mate-
rial filtered off and the filtrate concentrated to give
(0.14 g, 26% yield) as an orange solid. Mp 196–198 ꢁC
(dec); 1H NMR (400 MHz, CDCl3): d 8.70 (s, 1H),
7.93 (s, 1H), 7.90 (d, J = 2.4 Hz, 1H), 7.85 (d,
J = 8.0 Hz, 1H), 7.56 (dd, J = 8.8, 2.4 Hz, 1H).
4.14. 2-{4-[(7-Chloro-4-imidazo[1,5-a]quinoxalinyl)-
oxy]phenoxy}propionic acid (7c)
The methyl ester of 7c was prepared by refluxing for 4 h
a
mixture of 6c (0.14 g, 0.59 mmol), 4 (0.12 g,
0.61 mmol), anhydrous K2CO3 (0.11 g, 0.80 mmol)
and CH3CN (5 mL). Pure material (0.15 g, 65% yield)
was obtained after recrystallization from CH3OH to
give off-white crystals. Mp 195–197 ꢁC; 1H NMR
(400 MHz, CDCl3): d 8.69 (s, 1H), 7.94 (s, 1H), 7.80
(d, J = 9.2 Hz, 1H), 7.63 (d, J = 2.4 Hz, 1H), 7.38 (dd,
J = 9.2, 2.0 Hz, 1H), 7.23–7.18 (m, 2H), 6.97–6.92 (m,
2H), 4.79 (q, J = 7.2 Hz, 1H), 3.80 (s, 3H), 1.66 (d,
J = 7.6 Hz, 3H). 13C NMR (100 MHz, CDCl3): d
172.8, 155.5, 155.4, 146.1, 136.6, 132.6, 130.6, 128.5,
126.7, 126.6, 123.1, 122.9, 118.2, 116.1, 115.4, 73.3,
52.7, 18.9. IR (KBr) 1735 (C@O) cmÀ1. MS (EI) m/z
(%) 397 (M+, 100), 338 (62), 310 (86), 294 (15), 284
(6), 255 (7), 202 (28), 175 (26), 169 (9), 148 (12), 139
(5), 124 (6), 111 (7), 101 (7), 97 (14), 95 (10), 91 (15),
86 (9), 83 (18), 81 (15), 71 (14), 69 (26), 67 (16), 63
(11), 59 (13), 57 (29), 55 (35), 51 (7), 45 (6). Anal.
(C20H16N3ClO4) C, H, N.
55.5, 45.4. IR (KBr) 1655 (C@O) cmÀ1
.
4.11. 7-Chloro-5-(4-methoxybenzyl)-4(5H)-imidazo[1,5-
a]quinoxalinone
To a mixture of 60% NaH (0.30 g, 7.5 mmol) in anhy-
drous THF (5 mL) at 0 ꢁC, a mixture of 1-(4-methoxy-
benzyl)-2(1H)-7-chloroquinoxalinone (0.86 g, 2.9 mmol)
and p-tosylmethyl isocyanide (0.60 g, 3.0 mmol) in
anhydrous THF (10 mL) was added slowly and the mix-
ture stirred for 1 h at room temperature. After adding to
water (100 mL) the mixture was filtered, washed with
water and ether and dried to give (0.91 g, 94% yield)
The methyl ester of 7c (0.11 g, 0.27 mmol), dissolved in
THF (10 mL), was hydrolyzed with 0.1 M NaOH
(5.5 mL, 0.55 mmol) to give 7c (0.10 g, 95% yield) as
off-white crystals after recrystallization from EtOH–
1
1
as a beige solid. Mp 221–223 ꢁC; H NMR (400 MHz,
water. Mp 234–236 ꢁC; H NMR (400 MHz, DMSO-
DMSO-d6): d 9.10 (s, 1H), 8.28 (d, J = 8.4 Hz, 1H),
7.96 (s, 1H), 7.42 (s, 1H), 7.37 (d, J = 8.0 Hz, 1H),
7.22 (d, J = 8.8 Hz, 2H), 6.86 (d, J = 8.8 Hz, 2H), 5.39
(s, 2H), 3.68 (s, 3H).
d6): d 13.10 (br s, 1H), 9.29 (s, 1H), 8.33 (d,
J = 8.4 Hz, 1H), 7.96 (s, 1H), 7.56–7.52 (m, 3H), 7.28–
7.23 (m, 2H), 6.97–6.91 (m, 2H), 4.84 (q, J = 6.8 Hz,
1H), 1.52 (d, J = 6.4 Hz, 3H). 13C NMR (100 MHz,

1076
S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
DMSO-d6): d 173.8, 155.7, 145.9, 136.3, 131.6, 127.3,
126.8, 123.6, 117.6, 116.1, 72.5, 19.0. IR (KBr) 3450
(OH), 1720 (C@O) cmÀ1. MS (EI) m/z (%) 383 (M+,
97), 338 (15), 324 (8), 310 (100), 294 (7), 275 (5), 255
(9), 202 (30), 175 (29), 169 (7), 148 (13), 136 (5), 124
(6), 110 (6), 100 (5), 91 (6), 75 (7), 69 (5), 65 (6), 63
(9), 55 (7), 50 (6), 45 (5). HRMS (EI) m/z 383.0672,
(M+, calcd for C19H14N3ClO4 383.0673). Anal.
(C19H14N3ClO4), C: calcd, 59.46; found, 58.37. H: calcd,
3.68; found 4.37. N: calcd, 10.95, found, 10.44.
(0.44 g, 51% yield) was obtained after recrystallization
from CHCl3 as off-white crystals: H NMR (400 MHz,
1
DMSO-d6): d 13.08 (br s, 1H), 8.78 (d, J = 8.0 Hz,
1H), 8.60 (d, J = 8.0 Hz, 1H), 8.46 (d, J = 8.0 Hz, 1H),
7.99 (t, J = 7.6 Hz, 1H), 7.84 (t, J = 7.6 Hz, 1H), 7.75
(d, J = 2.4 Hz, 1H), 7.67 (dd, J = 8.8, 2.4 Hz, 1H),
7.29–7.24 (m, 2H), 6.99–6.93 (m, 2H), 4.85 (q,
J = 6.8 Hz, 1H), 1.53 (d, J = 7.2 Hz, 3H). 13C NMR
(100 MHz, DMSO-d6): d 173.9, 159.9, 155.4, 147.2,
143.8, 134.9, 132.9, 130.1, 129.2, 128.6, 125.4, 123.7,
123.3, 122.6, 122.2, 119.6, 116.1, 72.5, 19.1. IR (KBr)
3430 (OH), 1700 (C@O) cmÀ1. MS (EI) m/z (%) 437
(M+, 11), 393 (7), 364 (9), 273 (100), 256 (13), 229
(24), 212 (8), 195 (5), 182 (39), 177 (25), 166 (28), 164
(9), 139 (24), 137 (15), 110 (68), 97 (9), 83 (12), 81
(16), 74 (20), 69 (24), 65 (11), 60 (15), 57 (21), 55 (23),
45 (7). HRMS (EI) m/z 437.0261 (M+, calcd for
C22H16N79BrO4 437.0263). Anal. (C22H16NBrO4) C,
H, N.
4.15. 4-Bromobiphenyl 2-isocyanate
To a solution of 2-amino-4-bromobiphenyl15 (3.72 g,
15.0 mmol) in toluene (50 mL), triphosgene (1.66 g,
5.5 mmol) was added slowly and the mixture refluxed
for 1 h. After cooling it was concentrated to give
1
(4.08 g, 99% yield) as a light yellow liquid. H NMR
(400 MHz, CDCl3): d 7.50–7.37 (m, 6H), 7.35 (d,
J = 1.6 Hz, 1H), 7.20 (d, J = 9.2 Hz, 1H).
4.19. 2-{4-[(7-Bromo-4-methyl-2-quinolinyl)oxy]phen-
oxy}propionic acid (12a)
4.16. 3-Bromo-6-phenanthridinol
A
mixture of 11a (0.51 g, 2.0 mmol), 9 (0.36 g,
To a mixture of anhydrous AlCl3 (2.4 g, 18 mmol) and
PhCl (25 mL) at 100 ꢁC, 4-bromobiphenyl 2-isocyanate
(4.52 g, 16.5 mmol) in PhCl (10 mL) was added and
the mixture refluxed for 1 h. After cooling it was added
to water and the mixture boiled to remove the PhCl.
After the aqueous mixture had cooled it was filtered,
washed with water and ether, and dried to give (2.56 g,
57% yield) as a white solid. 1H NMR (400 MHz,
DMSO-d6): d 11.76 (s, 1H), 8.48 (d, J = 8.0 Hz, 1H),
8.33 (d, J = 8.8 Hz, 1H), 8.29 (dd, J = 8.0, 1.6 Hz, 1H),
7.85 (dt, J = 8.0, 1.6 Hz, 1H), 7.65 (t, J = 8.4 Hz,
1H), 7.52 (d, J = 1.6 Hz, 1H), 7.40 (dd, J = 8.4, 2.0 Hz,
1H).
2.0 mmol), anhydrous K2CO3 (0.69 g, 5.0 mmol), and
DMF (5 mL) were refluxed overnight. The pure product
(0.45 g, 56% yield) was obtained after chromatography
(1:1 hexanes–AcOEt) and recrystallization from
CHCl3–hexanes as off-white crystals. Mp 168–170 ꢁC;
1H NMR (400 MHz, DMSO-d6): d 13.07 (br s, 1H),
7.91 (d, J = 8.8 Hz, 1H), 7.77 (d, J = 1.6 Hz, 1H), 7.59
(dd, J = 9.2, 1.6 Hz, 1H), 7.16–7.10 (m, 3H), 6.92–6.88
(m, 2H), 4.82 (q, J = 6.8 Hz, 1H), 2.63 (s, 3H), 1.51 (d,
J = 7.2 Hz, 3H). 13C NMR (100 MHz, DMSO-d6): d
173.9, 162.9, 155.2, 149.5, 147.3, 147.2, 130.0, 128.2,
126.8, 125.0, 123.7, 123.3, 116.1, 113.7, 72.5, 19.1,
18.8. IR (KBr) 3420 (OH), 1715 (C@O) cmÀ1. MS
(EI) m/z (%) 401 (M+, 68), 356 (17), 342 (23), 328 (49),
314 (8), 300 (5), 250 (11), 220 (65), 204 (6), 141 (100),
114 (21), 109 (6), 102 (5), 81 (5), 75 (5), 69 (5), 63 (11),
57 (5), 55 (6), 51 (5), 45 (6). HRMS (EI): m/z 401.0265
(M+, calcd for C19H16N79BrO4 401.0263). Anal.
(C19H16NBrO4) C, H, N. (R) enantiomer: [a]D +33.4 (c
0.50, 0.1 MNaOH), 84% yield. Chiral HPLC separation
((S) enantiomer 9.4 min (R) enantiomer 12.3 min) using
4.17. 3-Bromo-6-chlorophenanthridine (8)
A
mixture of 3-bromo-6-phenanthridinol (4.44 g,
16.2 mmol) and POCl3 (7.4 mL, 12.4 g, 80.8 mmol)
was refluxed for 1 h. After cooling it was concentrated
to give a brown solid, which was added to water and
NaHCO3 added slowly until pH 7. The mixture was fil-
tered, washed with water, and dried to give an off-white
solid. This was heated with CHCl3, the insoluble mate-
rial filtered off, and the filtrate concentrated and recrys-
tallized to give (4.37 g, 92% yield) as off-white crystals.
AstecChirobioticT 250
CH3OH, 20 mM NH4NO3 at 1 mL/min with detection
at 250 nm.
· 4.6 mm, 65% H2O, 35%
1
Mp 192–194 ꢁC; H NMR (400 MHz, CDCl3): d 8.52
4.20. N,N0-Bis-(3-bromophenyl)malonamide (14)
(d, J = 8.0 Hz, 1H), 8.45 (d, J = 8.0 Hz, 1H), 8.33 (d,
J = 9.2 Hz, 1H), 8.21 (d, J = 2.4 Hz, 1H), 7.93–7.88
(m, 1H), 7.77 (dd, J = 7.2, 1.6 Hz, 1H), 7.74 (dd,
J = 8.8, 2.0 Hz, 1H).
A
mixture of 3-bromoanaline (2.78 mL, 4.30 g,
25.0 mmol) and diethyl malonate (1.92 mL, 2.00 g,
12.5 mmol) was heated at 220 ꢁC for 18 h. The resulting
brown solid was dissolved in AcOEt and filtered
through silica gel. The filtrate was concentrated to a
small volume and recrystallized from AcOEt–hexanes
to give (3.87 g, 75% yield) as cream-colored crystals.
Mp 168–170 ꢁC; H NMR (400 MHz, CDCl3): d 9.34
(s, 2H), 7.88 (s, 2H), 7.43 (d, J = 8.4 Hz, 2H), 7.28
(d, J = 8.4 Hz, 2H), 7.20 (t, J = 8.0 Hz, 2H), 3.61
(s, 2H).
4.18. 2-{4-[(3-Bromo-6-phenanthridinyl)oxy]phenoxy}-
propionic acid (10)
1
A mixture of 8 (0.58 g, 2.0 mmol), 9 (0.36 g, 2.0 mmol),
anhydrous K2CO3 (0.69 g, 5.0 mmol), and DMF
(10 mL) were refluxed overnight. (Note: aqueous solu-
tion not filtered due to low solubility.) The pure product

S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1077
4.21. 5-Bromo-4-hydroxy-2-quinolinol (15a) and
7-bromo-4-hydroxy-2-quinolinol (15b)
4.24. 2-{4-[(7-Bromo-4-methoxy-2-quinolinyl)oxy]phen-
oxy}propionic acid (12b)
N,N0-Bis-(3-bromophenyl)malonamide (4.51 g, 10.9
mmol) was dissolved in 7.7% P2O5/CH3SO3H (10 mL)
and heated at 160 ꢁC for 1.5 h. The resulting dark brown
solution was poured on ice, filtered, and washed with
water. The crude product was dissolved in 0.5 M NaOH,
the insoluble material was filtered off, and the filtrate
was acidified with concentrated HCl to pH 5. The pre-
cipitated solid was filtered and washed with cold water
to give (2.59 g, 98% yield) as a white solid (1:1 7-Br:5-
Br). Mp ꢁ 340 ꢁC; 5-Bromo-4-hydroxy-2-quinolinol;
1H NMR (400 MHz, DMSO-d6): d 11.50 (s, 1H), 11.40
(s, 1H), 7.31–7.23 (m, 3H), 5.77 (s, 1H). 7-Bromo-4-hy-
The methyl ester of 12b was prepared by refluxing for
several days a mixture of 11b (0.27 g, 1.0 mmol), 4
(0.20 g, 1.0 mmol), anhydrous K2CO3 (0.17 g,
1.3 mmol), and CH3CN (10 mL). Pure material (0.07 g,
19% yield) was obtained after chromatography (tolu-
ene!4:1 hexanes–AcOEt) and recrystallization from
AcOEt–hexanes to give white crystals. Mp 140–142 ꢁC;
1H NMR (400 MHz, CDCl3): d 7.91 (d, J = 8.8 Hz,
1H), 7.86 (d, J = 1.6 Hz, 1H), 7.43 (dd, J = 9.2, 1.6 Hz,
1H), 7.17–7.11 (m, 2H), 6.95–6.89 (m, 2H), 6.38 (s,
1H), 4.77 (q, J = 6.8 Hz, 1H), 4.00 (s, 3H), 3.79 (s,
1H), 1.64 (d, J = 7.6 Hz, 3H). 13C NMR (100 MHz,
CDCl3): d 173.0, 164.9, 164.2, 154.8, 147.9, 130.0,
127.5, 124.6, 123.4, 122.9, 118.4, 116.2, 91.3, 73.4,
56.2, 52.7, 18.9. IR (KBr) 1740 (C@O) cmÀ1. MS (EI)
m/z (%) 431 (M+, 58), 372 (27), 344 (35), 328 (5), 266
(7), 256 (8), 236 (34), 221 (9), 213 (6), 171 (16), 149
(47), 137 (7), 129 (29), 127 (10), 114 (17), 112 (12), 98
(28), 95 (15), 87 (12), 85 (18), 83 (31), 81 (35), 79 (10),
73 (44), 71 (36), 69 (82), 67 (24), 60 (44), 57 (100), 55
(79). Anal. (C20H18BrNO5) C, H, N.
1
droxy-2-quinolinol; H NMR (400 MHz, DMSO-d6): d
11.39 (s, 1H), 11.26 (s, 1H), 7.66 (d, J = 8.4 Hz, 1H),
7.41 (d, J = 1.6 Hz, 1H), 7.36 (dd, J = 7.6, 1.6 Hz, 1H),
5.72 (s, 1H).
4.22. 5-Bromo-4-methoxy-2-quinolinol and 7-bromo-4-
methoxy-2-quinolinol
A mixture of 7-bromo-(5-bromo)-4-hydroxy-2-quinol-
inol (1.99 g, 8.29 mmol) and acetone (350 mL), K2CO3
(2.29 g, 16.6 mmol), and (CH3)2SO4 (0.95 mL, 1.3 g,
10 mmol) was refluxed for 2.5 h. After removing the sol-
vent, the yellow solid was mixed with water, and neu-
tralized with 1 M HCl. The light yellow solid (2.1 g,
ꢀ 100% yield) was filtered and washed with water. 5-
Bromo-4-methoxy-2-quinolinol; 1H NMR (400 MHz,
DMSO-d6): d 11.54 (s, 1H), 7.35–7.26 (m, 3H), 5.93 (s,
1H), 3.90 (s, 3H). 7-Bromo-4-methoxy-2-quinolinol;
1H NMR (400 MHz, DMSO-d6): d 11.42 (s, 1H), 7.65
(d, J = 9.2 Hz, 1H), 7.43 (d, J = 2.8 Hz, 1H), 7.40 (dd,
J = 7.2, 1.6 Hz, 1H), 5.90 (s, 1H), 3.86 (s, 3H).
The methyl ester of 12b (0.11 g, 0.25 mmol), dissolved in
THF (5 mL), was hydrolyzed with 0.1 M NaOH (5 mL,
0.5 mmol) to give 12b (0.08 g, 76% yield) as white crys-
tals after recrystallization from CHCl3–hexanes. Mp
1
145–146 ꢁC; H NMR (400 MHz, CDCl3): d 11.28 (br
s, 1H), 7.91–7.86 (m, 2H), 7.42 (dd, J = 8.8, 2.4 Hz,
1H), 7.11–7.06 (m, 2H), 6.96–6.90 (m, 2H), 6.27 (s,
1H), 4.76 (q, J = 6.8 Hz, 1H), 3.95 (s, 3H), 1.67 (d,
J = 7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3): d
175.7, 165.1, 164.4, 154.7, 147.8, 147.5, 129.6, 127.6,
124.9, 123.5, 123.0, 118.3, 116.4, 91.1, 73.1, 56.3, 18.7.
IR (KBr) 3440 (OH), 1730 (C@O) cmÀ1. MS (EI) m/z
(%) 417 (M+, 83), 372 (24), 358 (34), 344 (74), 338 (5),
330 (11), 315 (5), 304 (5), 266 (16), 236 (100), 221 (31),
208 (8), 195 (6), 178 (5), 157 (8), 127 (22), 114 (59),
109 (9), 102 (6), 100 (7), 97 (8), 91 (7), 88 (8), 83 (11),
81 (11), 75 (15), 69 (16), 63 (22), 57 (19), 55 (20), 45
(13). HRMS (EI) m/z 419.0196 (M+, calcd for
C19H1681BrNO5, 419.0191). Anal. (C19H16BrNO5) C,
H, N. Chiral HPLC separation ((S) enantiomer
6.7 min (R) enantiomer 7.7 min) using AstecChirobiotic
T 250 · 4.6 mm, 100 CH3OH, 0.1 AcOH, 0.1 Et3N at
0.5 mL/min with detection at 236 nm.
4.23. 5-Bromo-2-chloro-4-methoxyquinoline and 7-
bromo-2-chloro-4-methoxyquinoline (11b)
The mixture of 7-bromo-(5-bromo)-4-methoxy-2-quino-
linol (2 g, 8 mmol) and POCl3 (3.6 mL, 39 mmol) was
refluxed for 1 h. After the removal of excess POCl3,
the dark brown viscous liquid was added to water, and
NaHCO3 added slowly until pH 7, followed by ex-
tracted using AcOEt (2 · 50 mL). The organiclayer
was washed with saturated NaCl (10 mL), dried over
anhydrous MgSO4, and concentrated to give a yellow
solid. The solid was purified by filtering through silica
gel with CHCl3 and the regioisomers were separated
utilizing column chromatography using toluene as the
elutent. Both regioisomers were recrystallized using
hexanes eluting first as white, needle-like crystals of 5-
bromo-2-chloro-4-methoxyquinoline (0.50 g, 23% yield).
Mp 119–120 ꢁC; 1H NMR (400 MHz, CDCl3): d 7.89 (d,
J = 7.6 Hz, 1H), 7.78 (d, J = 8.0 Hz, 1H), 7.46 (t,
J = 8.0 Hz, 1H), 6.78 (s, 1H) and followed by white
shorter crystals of 7-bromo-2-chloro-4-methoxyquino-
line (0.65 g, 30% yield). Mp 147–148 ꢁC; 1H NMR
(400 MHz, CDCl3): d 8.10 (d, J = 2.4 Hz, 1H), 7.98 (d,
J = 8.8Hz, 1H), 7.58 (dd, J = 8.8, 2.0 Hz, 1H), 6.74 (s,
1H), 4.05 (s, 3H).
4.25. N-(3-Bromophenyl)-3-(3-bromophenylamino)-4,4,4-
trifluoro-2-butenamide and ethyl 3-(3-bromophenylamino)-
4,4,4-trifluoro-2-butenoate
A mixture of 3-bromoaniline (3.7 mL, 5.8 g, 33 mmol),
ethyl
4,4,4-trifluoroacetoacetate
(5.0 mL,
6.3 g,
33 mmol), and PhCH3 (25 mL) were heated at 110 ꢁC
overnight. After cooling it was concentrated to give an
orange-yellow liquid, which was purified by column
chromatography using 10:1!4:1 hexanes–AcOEt as
the elutent. Ethyl 3-(3-bromophenylamino)-4,4,4-triflu-
1
oro-2-butenoate eluted first as a light yellow liquid. H
NMR (400 MHz, CDCl3): d 9.80 (br s, 1H), 7.39–7.04
(m, 4H), 5.39 (s, 1H), 4.25–4.17 (m, 2H), 1.34–1.25 (m,

1078
S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
3H).
N-(3-Bromophenyl)-3-(3-bromophenylamino)-
1H NMR (400 MHz, DMSO-d6): d 13.08 (br s, 1H),
7.95 (d, J = 1.6 Hz, 1H), 7.90 (bd, J = 7.2 Hz, 1H),
7.77 (dd, J = 8.8, 1.6 Hz, 1H), 7.74 (s, 1H), 7.24–7.18
(m, 2H), 6.97–6.91 (m, 2H), 4.83 (q, J = 6.4 Hz, 1H),
1.52 (d, J = 6.4 Hz, 3H). 13C NMR (100 MHz,
DMSO-d6): d 173.8, 162.1, 155.6, 148.0, 146.7, 137.2
(q, J = 32 Hz), 130.7, 130.3, 125.8, 125.2, 123.2, 123.2
(q, J = 273 Hz), 119.0, 116.2, 113.0 (d, J = 5 Hz), 72.6,
19.0. 19F NMR (376 MHz, DMSO-d6): d À61.45. IR
(KBr) 3420 (OH), 1745 (C@O) cmÀ1. MS (EI) m/z (%)
455 (M+, 97), 410 (23), 396 (20), 382 (60), 366 (10),
304 (18), 274 (54), 254 (19), 195 (20), 176 (8), 145 (8),
109 (5), 91 (5), 63 (7). HRMS (EI). m/z 456.9955
(M+, calcd for C19H13N81BrF3O4 456.9960). Anal.
(C19H13NBrF3O4) C, H, N.
4,4,4-trifluoro-2-butenamide eluted next and was recrys-
tallized using hexanes to give (4.08 g, 50% yield) as white
1
crystals. Mp 114–115 ꢁC; H NMR (400 MHz, CDCl3):
d 10.57 (br s, 1H), 7.79 (br s, 1H), 7.38–7.33 (m, 3H),
7.25–7.10 (m, 5H), 5.33 (s, 1H). 19F NMR (376 MHz,
CDCl3): d À63.5 (s).
4.26. 5-Bromo-4-trifluoromethyl-2-quinolinol and
7-bromo-4-trifluoromethyl-2-quinolinol
Cold concentrated H2SO4 (10 mL) was added to N-(3-
bromophenyl)-3-(3-bromophenylamino)-4,4,4-trifluoro-
2-butenamide (3.62 g, 7.80 mmol) and the mixture
allowed to warm to room temperature. After all of the
solid had dissolved it was heated at 100 ꢁC for 1 h. After
cooling it was poured onto ice and filtered, washing with
water, and dried to give (1.57 g, 69% yield) as a white
solid (11:1 7-Br:5-Br). 5-Bromo-4-trifluoromethyl-2-quin-
olinol; 1H NMR (400 MHz, DMSO-d6) (Partial): d
12.53 (br s, 1H), 7.64 (t, J = 4.4 Hz, 1H), 7.15 (s, 1H).
19F NMR (376 MHz, CDCl3): d À54.3 (s). 7-Bromo-4-
trifluoromethyl-2-quinolinol; 1H NMR (400 MHz,
DMSO-d6): d 12.36 (br s, 1H), 7.61–7.56 (m, 2H), 7.45
(dd, J = 8.8, 1.6 Hz, 1H), 7.00 (s, 1H). 19F NMR
(376 MHz, CDCl3): d À63.1 (s).
4.29. 7-Bromo-2-hydroxy-4-quinolinecarboxylic acid
A mixture of 6-bromoisatin20a,b (2.86 g, 12.7 mmol),
malonic acid (6.61 g, 63.5 mmol), and AcOH (125 mL)
was refluxed overnight. After cooling it was concen-
trated to give a brown solid to which water (100 mL)
was added. The mixture was filtered and washed with
water to give a brown solid. This was heated with NaH-
CO3 solution and the insoluble material filtered off. The
filtrate was acidified to pH 1 with concentrated HCl and
the mixture filtered, washed with water, and dried to
give (2.54 g, 75% yield) as a brown-yellow solid. 1H
NMR (400 MHz, DMSO-d6): d 12.14 (br s, 2H), 8.12
(d, J = 9.2 Hz, 1H), 7.54 (d, J = 2.4 Hz, 1H), 7.38 (dd,
J = 8.8, 2.4 Hz, 1H), 6.90 (s, 1H).
4.27. 7-Bromo-2-chloro-4-trifluoromethylquinoline (11c)
and 5-bromo-2-chloro-4-trifluoro-methylquinoline
The mixture of 7-bromo-(5-bromo)-4-trifluoromethyl-2-
quinolinol (1.80 g, 6.17 mmol) and POCl3 (2.9 mL,
4.9 g, 31 mmol) was refluxed for 1 h. After the removal
of excess POCl3, the dark brown viscous liquid was
added to water, and NaHCO3 added slowly until
pH 7, and the mixture was extracted using AcOEt
(2 · 50 mL). The organiclayer was washed with satu-
rated NaCl (10 mL), dried over anhydrous MgSO4,
and concentrated to give a brown-yellow solid. The solid
was purified by filtering through silica gel with CHCl3
and the regioisomers were separated utilizing column
chromatography using 20:1 hexanes–AcOEt as the
elutent. 7-Bromo-2-chloro-4-trifluoromethylquinoline
eluted first as a light yellow liquid that solidified.
(1.60 g, 84% yield). Mp 45–46 ꢁC; 1H NMR
(400 MHz, CDCl3): d 8.30 (d, J = 2.4 Hz, 1H), 7.99–
7.94 (m, 1H), 7.78 (dd, J = 8.8, 2.4 Hz, 1H), 7.70 (s,
1H). 19F NMR (376 MHz, CDCl3): d À62.1 (s). 5-Bro-
mo-2-chloro-4-trifluoromethylquinoline as a light yel-
low liquid that solidified. 1H NMR (400 MHz,
CDCl3): d 8.14–8.08 (m, 2H), 7.90 (s, 1H), 7.63 (t,
J = 8.0 Hz, 1H). 19F NMR (376 MHz, CDCl3): d
À52.3 (s).
4.30. 7-Bromo-2-chloro-4-quinolinecarboxylic acid (11d)
A mixture of 7-bromo-2-hydroxy-4-quinolinecarboxylic
acid (2.53 g, 9.44 mmol) and POCl3 (4.3 mL, 7.2 g,
47 mmol) was refluxed for 1 h. After cooling it was con-
centrated to give a black solid, which was added to
water and NaHCO3 added slowly until pH 8. The insol-
uble material was filtered off and the filtrate was acidi-
fied to pH 3 with concentrated HCl. The solid was
filtered, washed with water, and dried to give an off-
white solid. The solid was purified by filtering through
silica gel with hot AcOEt, and the filtrate concentrated
and recrystallized to give (1.56 g, 58% yield) as off-white
1
crystals. Mp 218–220 ꢁC; H NMR (400 MHz, DMSO-
d6): d 8.61 (d, J = 8.8 Hz, 1H), 8.28 (d, J = 2.4 Hz, 1H),
7.95 (s, 1H), 7.90 (dd, J = 9.2, 2.0 Hz, 1H).
4.31. 2-{4-[(7-Bromo-4-carboxy-2-quinolinyl)oxy]phen-
oxy}propionic acid (12d)
A
mixture of 11d (0.43 g, 1.5 mmol), 9 (0.27 g,
1.5 mmol), anhydrous K2CO3 (0.73 g, 5.3 mmol), and
DMF (5 mL) were refluxed overnight. The pure product
(0.53 g, 82% yield) was obtained after recrystallization
from acetone–CHCl3 as light yellow crystals. Mp 230–
4.28. 2-{4-[(7-Bromo-4-trifluoromethyl-2-quinolinyl)-
oxy]phenoxy}propionic acid (12c)
1
A
mixture of 11c (0.31 g, 1.0 mmol),
9
(0.18 g,
231 ꢁC; H NMR (400 MHz, DMSO-d6): d 13.40 (br s,
1.0 mmol), anhydrous K2CO3 (0.35 g, 2.5 mmol), and
DMF (2 mL) were refluxed overnight. The pure product
(0.11 g, 24% yield) was obtained after chromatography
(1:1 hexanes–AcOEt) and recrystallization from
CHCl3–hexanes as off-white crystals. Mp 166–168 ꢁC;
2H), 8.51 (d, J = 8.8 Hz, 1H), 7.87 (d, J = 2.4 Hz, 1H),
7.68 (dd, J = 9.2, 2.0 Hz, 1H), 7.59 (s, 1H), 7.22–7.16
(m, 2H), 6.96–6.90 (m, 2H), 4.83 (q, J = 6.8 Hz, 1H),
1.52 (d, J = 7.2 Hz, 3H). 13C NMR (100 MHz,
DMSO-d6): d 173.8, 167.1, 162.6, 155.4, 148.1, 147.1,

S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1079
141.3, 130.1, 129.5, 128.2, 124.5, 123.3, 121.7, 116.3,
115.2, 72.6, 19.0. IR (KBr) 3420 (OH), 1725 (C@O),
1705 (C@O) cmÀ1. MS (EI) m/z (%) 431 (M+, 100),
386 (26), 372 (22), 358 (61), 342 (14), 314 (21), 287 (6),
280 (18), 267 (12), 250 (41), 236 (5), 206 (23), 194 (11),
191 (5), 182 (9), 178 (11), 175 (31), 171 (7), 143 (11),
127 (42), 115 (18), 110 (19), 100 (14), 94 (16), 91 (15),
84 (17), 81 (15), 76 (16), 73 (20), 69 (27), 65 (17), 63
(18), 59 (72), 57 (31), 55 (47), 51 (15), 45 (30). HRMS
(EI) m/z 432.9984 (M+, calcd for C19H14N81BrO6
432.9984). Anal. (C19H14NBrO6) C, H, N.
DMF (2 mL) were refluxed overnight. The pure product
(0.38 g, 83% yield) was obtained after chromatography
(1:2 hexanes–AcOEt) and recrystallization from
CHCl3–hexanes as yellow crystals. Mp 152–154 ꢁC; H
1
NMR (400 MHz, DMSO-d6): d 13.07 (br s, 1H), 7.87
(d, J = 1.6 Hz, 1H), 7.64 (d, J = 8.8 Hz, 1H), 7.61–7.51
(m, 6H), 7.22–7.16 (m, 3H), 6.96–6.90 (m, 2H), 4.83
(q, J = 6.8 Hz, 1H), 1.52 (d, J = 6.4 Hz, 3H). 13C
NMR (100 MHz, DMSO-d6): d 173.9, 162.7, 155.3,
152.5, 147.9, 147.2, 137.1, 130.1, 129.9, 129.7, 129.5,
128.8, 128.0, 124.1, 123.4 (2C), 116.2, 113.5, 72.5, 19.1.
IR (KBr) 3430 (OH), 1725 (C@O) cmÀ1. MS (EI) m/z
(%) 463 (M+, 93), 418 (22), 404 (25), 390 (44), 385 (5),
374 (7), 312 (16), 299 (8), 282 (66), 254 (5), 203 (100),
190 (6), 176 (18), 165 (8), 151 (5), 110 (6), 77 (9), 69
(5), 63 (6), 57 (5), 55 (7), 51 (5). HRMS (EI) m/z
463.0414 (M+, calcd for C24H18N79BrO4 463.0419).
Anal. (C24H18NBrO4) C, H, N.
4.32. N-(3-Bromophenyl)-3-oxo-3-phenylpropionamide
A mixture of 3-bromoaniline (2.25 mL, 3.6 g, 20 mmol),
ethyl benzoylacetate (3.6 mL, 4.0 g, 20 mmol), and
PhCH3 (10 mL) were heated at 110 ꢁC overnight. After
cooling it was concentrated to give an orange-yellow
solid, which was purified by washing with 10:1 hexanes–
AcOEt followed by recrystallization from hexanes–
AcOEt to give (3.01 g, 47% yield) as white crystals.
4.36. 2-{4-[(7-Bromo-4-quinolinyl)oxy]phenoxy}propionic
acid (17a)
1
Mp 120–121 ꢁC; H NMR (400 MHz, CDCl3): d 9.48
(br s, 1H), 8.03 (d, J = 8.0 Hz, 2H), 7.89–7.86 (m, 1H),
7.66 (t, J = 8.0 Hz, 1H), 7.54 (d, J = 8.0 Hz, 1H), 7.53–
7.47 (m, 2H), 7.25 (d, J = 5.6 Hz, 1H), 7.19 (t,
J = 8.0 Hz, 1H), 4.12 (s, 2H).
A mixture of 16a (0.49 g, 2.0 mmol), 7 (0.37 g,
2.0 mmol), anhydrous K2CO3 (0.69 g, 5.0 mmol), and
DMF (5 mL) were refluxed overnight. The pure product
(0.56 g, 72% yield) was obtained after recrystallization
from AcOEt as white crystals. Mp 197–198 ꢁC; 1H
NMR (400 MHz, DMSO-d6): d 13.05 (br s, 1H), 8.67
(d, J = 4.8 Hz, 1H), 8.23 (d, J = 8.8 Hz, 1H), 8.21 (d,
J = 1.6 Hz, 1H), 7.76 (dd, J = 8.8 Hz, 1.6 Hz, 1H),
7.26–7.20 (m, 2H), 7.03–6.97 (m, 2H), 6.54 (d,
J = 5.6 Hz, 1H), 4.86 (q, J = 6.8 Hz, 1H), 1.52 (d,
J = 6.4 Hz, 3H). 13C NMR (100 MHz, DMSO-d6): d
173.7, 162.3, 156.0, 153.5, 150.4, 147.6, 131.3, 130.0,
124.4, 124.3, 122.9, 120.1, 117.1, 104.9, 72.6, 19.0. IR
(KBr) 3430 (OH), 1720 (C@O) cmÀ1. MS (EI) m/z (%)
387 (M+, 2), 256 (14), 236 (9), 213 (10), 199 (5), 194
(5), 185 (10), 171 (6), 157 (6), 152 (6), 143 (5), 138 (6),
129 (26), 125 (9), 123 (9), 115 (12), 111 (19), 101 (11),
97 (39), 95 (23), 87 (15), 85 (31), 83 (53), 81 (31), 73
(78), 71 (51), 69 (81), 67 (32), 60 (71), 57 (99), 55
(100), 45 (12). HRMS (EI) m/z 387.0102 (M+, calcd
for C18H1479BrNO4, 387.0106). Anal. (C18H14BrNO4)
H, N; C: calcd, 55.69, found 53.62. (R) enantiomer:
[a]D +44.4ꢁ (c = 0.50, 0.1 M NaOH), mp 203–204 ꢁC,
81% yield. Chiral HPLC separation ((S) enantiomer
6.6 min (R) enantiomer 8.0 min) using AstecChirobiotic
T 250 · 4.6 mm, 100 CH3OH, 0.1 AcOH, 0.1 Et3N at
0.5 mL/min with detection at 232 nm.
4.33. 7-Bromo-4-phenyl-2-quinolinol
Cold concentrated H2SO4 (10 mL) was added to N-(3-
Bromophenyl)-3-oxo-3-phenyl-propionamide
(3.00 g,
9.43 mmol) and the mixture allowed to warm to room
temperature. After all of the solid had dissolved it was
heated at 100 ꢁC for 1 h. After cooling it was poured
onto ice and filtered, washing with water, and dried to
give (1.30 g, 46% yield) as a light brown solid. 1H
NMR (400 MHz, DMSO-d6): d 11.95 (br s, 1H), 7.8–
7.2 (m, 8H), 6.41 (s, 1H).
4.34. 7-Bromo-2-chloro-4-phenylquinoline (11e)
A mixture of 7-bromo-4-phenyl-2-quinolinol (1.29 g,
4.30 mmol) and POCl3 (2.0 mL, 3.4 g, 22 mmol) was re-
fluxed for 1 h. After the removal of excess POCl3, the
dark brown semi-solid was added to water and NaH-
CO3 added slowly until pH 7, followed by extracted
using AcOEt (2 · 50 mL). The organiclayer was washed
with saturated NaCl (10 mL), dried over anhydrous
MgSO4 and concentrated to give a brown liquid. The
mixture was purified by filtering through silica gel with
CHCl3 followed by column chromatography using
10:1 hexanes–AcOEt as the elutent. The product eluted
first and was recrystallized using 2-PrOH to give
(0.75 g, 53% yield) as white crystals. Mp 121–122 ꢁC;
1H NMR (400 MHz, CDCl3): d 8.25 (d, J = 1.6 Hz,
1H), 7.74 (d, J = 9.2 Hz, 1H), 7.58 (dd, J = 9.2, 2.4 Hz,
1H), 7.56–7.52 (m, 3H), 7.48–7.44 (m, 2H), 7.35 (s, 1H).
4.37. 2-{4-[(7-Chloro-4-quinolinyl)oxy]phenoxy}propionic
acid (17b)
A
mixture of 16b (0.40 g, 2.0 mmol), 9 (0.36 g,
2.0 mmol), anhydrous K2CO3 (0.69 g, 5.0 mmol), and
DMF (5 mL) was refluxed overnight. The pure product
(0.33 g, 48% yield) was obtained after recrystallization
from AcOEt–heptane to give off-white crystals. Mp
1
4.35. 2-{4-[(7-Bromo-4-phenyl-2-quinolinyl)oxy]phen-
oxy}propionic acid (12e)
197–198 ꢁC; H NMR (400 MHz, DMSO-d6): d 13.08
(br s, 1H), 8.68 (d, J = 4.8 Hz, 1H), 8.31 (d,
J = 8.8 Hz, 1H), 8.05 (d, J = 2.4 Hz, 1H), 7.65 (dd,
J = 9.2, 1.6 Hz, 1H), 7.26–7.20 (m, 2H), 7.03–6.97 (m,
2H), 6.53 (d, J = 4.8 Hz, 1H), 4.85 (q, J = 6.8 Hz, 1H),
A
1.0 mmol), anhydrous K2CO3 (0.35 g, 2.5 mmol), and
mixture of 11e (0.32 g, 1.0 mmol),
9 (0.18 g,

1080
S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1.52 (d, J = 7.2 Hz, 3H). 13C NMR (100 MHz, DMSO-
d6): d 173.7, 162.2, 156.0, 153.5, 150.2, 147.6, 135.6,
128.0, 127.4, 124.3, 122.9, 119.8, 117.1, 104.8, 72.7,
19.0. IR (KBr) 3420 (OH), 1720 (C@O) cmÀ1. MS
(EI) m/z (%) 343 (M+, 100), 298 (10), 270 (89), 242 (5),
235 (9), 219 (6), 162 (54), 149 (6), 135 (24), 127 (10),
110 (12), 99 (17), 97 (9), 91 (7), 83 (10), 81 (8), 74 (6),
71 (8), 69 (16), 67 (6), 63 (6), 57 (16), 55 (16). HRMS
(EI) m/z 343.0616 (M+, calcd for C18H14NClO4
343.0611). Anal. (C18H14NClO4) C, H, N. (R) isomer:
[a]D +37.2ꢁ (c = 0.50, 0.1 M NaOH), mp 194–195 ꢁC,
81% yield. Chiral HPLC separation ((S) enantiomer
6.7 min (R) enantiomer 8.5 min) using AstecChirobiotic
T 250 · 4.6 mm, 100 CH3OH, 0.1 AcOH, 0.1 Et3N at
0.5 mL/min with detection at 228 nm.
stage treatment, chemotherapy was started 1–3 days
after tumor implantation while the number of cells is rel-
atively small (107 to 5 · 107 cells). Tumors were mea-
sured with a caliper twice weekly, or three times
weekly for the more rapidly growing tumors. Mice were
sacrificed when their tumors reached 1500 mg (i.e., be-
fore they could cause the animal discomfort). Tumor
weights were estimated from two-dimensional measure-
ments. Dose schedules were adjusted for toxicity;
accordingly, doses reported in Table 2 are not the same,
because of the toxicity encountered at the top dose(s), at
which time treatment was terminated for all doses.
Therefore, the highest, achieved dose is reported.
4.39.3. Tumor weight. The tumor weight (in
mg) = (a · b2)/2, where a and b are the tumor length
and width (in mm), respectively.
4.38. Biologic evaluation methods: in vitro
4.39.4. Quantified end points for assessing antitumor
activity for solid tumors. The following quantified end
points are used to assess antitumor activity.
A brief description of the methods follows. All materials
were initially tested in a disk diffusion soft agar colony
formation assay (disk assay). The disk assay is designed
to compare the relative cytotoxicity of an agent against
leukemia cells, solid tumor cells (including multidrug
resistant solid tumors), and normal cells. The inhibition
is expressed in zone units, with 200 units = 6.5 mm. On
average, a 10-fold dilution of a cytotoxic agent produces
a 330 zone unit change. Activity against a drug sensitive
leukemia (L1210 or P388) provides the reference point.
The leukemic cell can represent antiproliferative leuke-
mic active agents of past discoveries. The agent needs
greater activity against the drug insensitive solid tumors
than against the leukemia cells. Normal fibroblasts were
also used in current studies. For the operation of the
assay, the tumor cells are isolated from live tissue, that
is, a tumor growing in a mouse. The cells are then seeded
in the soft agar. The drug is placed on a filter paper disk
(standard hole punch of Whatman no 1), which is then
placed on top of the soft agar (60 mm plate). The drug
diffuses off the disk as the tumor cells are replicating,
creating a zone of inhibition of colony formation. Those
materials with sufficient cytotoxicity (>400 units) and
tumor selectivity progressed to in vivo evaluation in
tumor-bearing mice as described below.
4.39.4.1. Tumor growth delay (T À C value). T is the
median time (in days) required for the treatment group
tumors to reach a predetermined size (e.g., 1000 mg),
and C is the median time (in days) for the control group
tumors to reach the same size. Tumor-free survivors are
excluded from these calculations (cures are tabulated
separately). In our judgment, this value is the single
most important criterion of antitumor effectiveness be-
cause it allows the quantification of tumor cell kill.
4.39.4.2. Calculation of tumor cell kill. For subcutane-
ously (SC) growing tumors, the log cell kill is calculated
from the following formula: log cell kill total (gross)
T À C value in days (3.32) (Td), where T À C is the tu-
mor growth delay as described above and Td is the tu-
mor volume doubling time in days, estimated from the
best fit straight line from a log-linear growth plot of
the control group tumors in exponential growth (100–
800 mg range). The conversion of the T À C values to
log cell kill is possible because the Td of tumors regrow-
ing post treatment (Rx) approximates the Td values of
the tumors in untreated control mice.
4.39. In vivo
Duration of treatment of solid tumor, 5–20 days
Treatment was carried out against early stage pancreatic
ductal adenocarcinoma-03, and/or early colon adeno-
carcinoma 38. All are sensitive to 1.
Antitumor activity
Gross log tumor cell kill
Highly active
++++
>2.8
+++
++
+
À
2.0–2.8
1.3–1.9
0.7–1.2
<0.7
4.39.1. Tumor and animal maintenance. Mouse tumors
were maintained in the mouse strain of origin and were
transplanted into the appropriate F1 hybrid (or the
inbred mouse of origin) for therapy trials. Individual
mouse body weights for each experiment were within
5 g, and all mice were over 17 g at the start of therapy.
The mice were supplied food and water ad libitum.
Inactive
4.39.4.3. Nonquantitative determination of antitumor
activity by tumor growth inhibition (T/C value). The
treatment and control groups are measured when the
control group tumors reach approximately 700–
1200 mg in size (median of group). The median tumor
weight of each group is determined, including zeros.
The T/C value in percent is an indication of antitumor
4.39.2. Chemotherapy of solid tumors. The animals were
pooled, implanted subcutaneously with 30–60 mg tumor
fragments by a 12 gauge trocar, and again pooled before
unselective distribution to the various treatment and
control groups (five or six mice per group). For early

S. T. Hazeldine et al. / Bioorg. Med. Chem. 13 (2005) 1069–1081
1081
Commun. 2001, 280, 1155; (d) Kessel, D.; Horwitz, J. P.
Cancer Lett. 2001, 168, 141144; (e) Ding, Z.; Parchment,
R. E.; LoRusso, P. M.; Zhou, J.-Y.; Jun, L.; Lawrence, T.
S.; Yi, S.; Wu, G. S. Clin. Cancer Res. 2001, 7, 3336; (f)
Mensah-Osman, E.; Al-Katib, A. M.; Dandashi, M. H.;
Mohammed, R. M. Mol. Cancer Ther. 2002, 1, 1315; (g)
Mensah-Osman, E.; Al-Katib, A. M.; Wu, H.-Y.; Osman,
N. J.; Mohammed, R. M. Mol. Cancer Ther. 2002, 1, 1321;
(h) Lin, H.; Liu, X. Y.; Subramanian, B.; Nakeff, A.;
Valeriote, F.; Chen, B. Int. J. Cancer 2002, 97, 121; (i) Lin,
H.; Subramanian, B.; Nakeff, A.; Chen, B. Cancer
Chemother. Pharmacol. 2002, 49, 281.
effectiveness. A T/C equal to or less than 42% is consid-
ered significant antitumor activity by the Drug Evalua-
tion Branch of the Division of Cancer Treatment
(NCI). A T/C value <10% is considered to indicate
highly significant antitumor activity, and is the level
used by NCI to justify a clinical trial if toxicity, formu-
lation, and certain other requirements are met (termed
DN-2 level activity). A body weight loss nadir (mean
of group) of greater than 20% or greater than 20% drug
deaths is considered to indicate an excessively toxic dos-
age in a single course trial.
6. Strader, C. D. J. Med. Chem. 1996, 39, 1.
7. Hazeldine, S.; Polin, L.; Kushner, J.; Paluch, J.; White, K.;
Edelstein, M.; Palomino, E.; Corbett, T. H.; Horwitz, J. P.
J. Med. Chem. 2001, 44, 1758.
Acknowledgements
8. Hazeldine, S. T.; Polin, L.; Kushner, J.; White, K.;
Bouregeois, N. M.; Crantz, B.; Palomino, E.; Corbett, T.
H.; Horwitz, J. P. J. Med. Chem. 2002, 45, 3130.
9. Horwitz, J. P.; Hazeldine, S. T.; Corbett, T. H.; Polin, L.
WO Patent 03/011832, 2003.
10. Newkome, G. R.; Garbis, S. J.; Majestic, V. K.; Fronczek,
F. R.; Chiari, G. J. J. Org. Chem. 1981, 46, 833.
11. (a) Brown, E. V.; Plasz, A. C. J. Org. Chem. 1971, 36,
1331; (b) Vanahm, R. A.; Paudler, W. W. J. Org. Chem.
1975, 40, 3068.
We are grateful for the support of this research through
grants from the National Institutes of Health
(CA82341), the Virtual Discovery Program of the Bar-
bara Ann Karmanos Institute, and the Jack and Miriam
Schenkman Research Fund. Thanks are due to the Re-
source Laboratory of the Chemistry Department,
Wayne State University, Detroit, MI, wherein instru-
mental analyses were performed.
12. (a) Guillon, J.; Dellemagne, P.; Pfeiffer, B.; Renard, P.;
Manechez, D.; Kervran, A.; Rault, S. Eur. J. Med. Chem.
1998, 33, 293; (b) Cheesman, G. W. H.; Hawi, A. A.;
Varvounis, G. J. Heterocycl. Chem. 1985, 22, 423.
13. (a) Johnson, A. L.; Kauer, J. C.; Sharma, D. C.; Dorfman,
R. L. J. Med. Chem. 1969, 12, 1024; (b) Campiania, G.;
Morelli, E. S.; Gemma, S.; Nacci, V.; Butini, S.; Hamon,
M.; Novrllino, E.; Greco, G.; Cagnotto, A.; Goegan, M.;
Cervo, L.; DallaValle, F.; Fracasso, C.; Caccia, S.;
Mennini, T. J. Med. Chem. 1999, 42, 4362.
14. Barrish, J. C.; Spergel, S. H. US Patent 6,239,133, 2001.
15. Badger, G. M.; Sasse, W. F. H. J. Chem Soc. 1957, 4.
16. Coyne, W. E.; Cusic, J. W. J. Med. Chem. 1968, 11, 1158.
17. Davis, S. E.; Rauckman, B. S.; Chan, J. H.; Roth, B.
J. Med. Chem. 1989, 32, 1936.
18. (a) Kappe, T.; Karem, A.; Stadlbauer, W. J. Heterocycl.
Chem. 1988, 25, 857; (b) Tagawa, Y.; Kawaoka, T.; Goto,
Y. J. Heterocycl. Chem. 1997, 34, 1677; (c) Belli, M. L.;
Illuminati, G.; Marino, G. Tetrahedron 1963, 19, 345.
19. Zhi, L.; Tegley, C.; Pio, B.; Arjan V. O. C.; Motamedi, M.;
Martinborough, E.; West, S.; Higuchi, R.; Hamann, L.;
Farmer, L. WO Patent 01/16108, 2001.
20. (a) Tokunaga, T.; Hume, W. E.; Umezome, T.; Okazaki,
K.; Ueki, Y.; Kumagai, K.; Hourai, S.; Nagamine, J.;
Seki, H.; Taiji, M.; Noguchi, H.; Nagata, R. J. Med.
Chem. 2001, 44, 4641; (b) Sadler, P. W. J. Org. Chem.
1956, 21, 169; (c) Wetzel, C. R.; Shanlin, J. R., Jr.; Lutz,
R. E. J. Med. Chem. 1973, 16, 528.
References and notes
1. LoRusso, P. M.; Demchik, L.; Knight, J.; Polin, L.;
Behrens, C. H.; McRipley, R.; Gross, J. L.; Harrison, B.
A.; Corbett, T. H. Proc. Am. Assoc. Cancer Res. 1994, 35,
401.
2. Corbett, T. H.; LoRusso, P. M.; Demchik, L.; Simpson,
C.; Pugh, S.; White, K.; Kushner, J.; Polin, L.; Meyer, J.;
Czarnecki, J.; Heilbrun, L.; Horwitz, J. P.; Gross, J. L.;
Behrens, C. H.; Harrison, B. A.; McRipley, R. J.; Trainor,
G. Invest. New Drugs 1998, 16, 129.
3. LoRusso, P. M.; Parchment, R.; Demchik, L.; Knight, J.;
Polin, L.; Dzubow, J.; Behrens, C.; Harrison, B. A.;
Trainor, G.; Corbett, T. H. Invest. New Drugs 1999, 16,
287.
4. Corbett, T. H.; Valeriote, F. A.; LoRusso, P. M.; Polin,
L.; Panchapor, C.; Pugh, S.; White, K.; Knight, J.;
Demchik, L.; Jones, J.; Jones, L.; Lowichik, N.; Biernat,
L.; Foster, B.; Wozniak, A.; Lisow, L.; Valdivieso, M.;
Baker, L.; Leopold, W.; Sebolt, J.; Bissery, M.-C.; Mattes,
K.; Dzubow, J.; Rake, J.; Perni, R.; Wentland, M.;
Coughlin, S.; Shaw, J. M.; Liverside, G.; Liversidge, E.;
Bruno, J.; Sarpotdar, P.; Moore, R.; Patterson, G. Int. J.
Pharmacogn. 1995, 33(Supp.), 102.
5. (a) Gao, H.; Huang, K.-C.; Yamasaki, E. F.; Chan, K. K.;
Chohan, L.; Snapka, R. M. Proc. Natl. Acad. Sci. U.S.A.
1999, 12168; (b) Gao, H.; Yamasaki, E. F.; Chan, K. K.;
Shen, L. L.; Snapka, R. M. Cancer Res. 2000, 60, 5937; (c)
Snapka, R. M.; Gao, H.; Grabowski, D. R.; Brill, D.;
Chan, K. K.; Li, L.; Li, G.-C. Biochem. Biophys. Res.
21. Tomcufcik, A. S. EP Patent 446604, 1991.
22. De, D.; Krogstad, F. M.; Byers, L. D.; Krogstad, D. J.
J. Med. Chem. 1998, 41, 4918.