Novel cyclopropapyrroloindole derivative (AT-3510) bearing methoxycarbonyl and trifluoromethyl groups

Article abstract of DOI:10.1021/jm980668c

The seco-Cl 3-methoxycarbonyl-2-trifluoromethylcyclopropapyrroloindole (MCTFCPI) derivatives dl- and/or (S)-10 carrying various acyl moleties at the N6-position were synthesized along with their prodrugs (S)-12, and their antitumor activity was evaluated. Among these derivatives, AT-3510 [(S)- 12m], the novel prodrug MCTFCPI derivative carrying a 5-(7- methoxybenzofuran-2-ylcarbonyl)aminoindole-2-carbonyl group at the N6- position, was found to exhibit more excellent antitumor activity against human tumor xenografts than the clinical trial candidates carzelesin (6) and KW-2189 (7) and cisplatin.

Full text of DOI:10.1021/jm980668c

1448
J . Med. Chem. 1999, 42, 1448-1458
Novel Cyclop r op a p yr r oloin d ole Der iva tive (AT-3510) Bea r in g Meth oxyca r bon yl
a n d Tr iflu or om eth yl Gr ou p s
Yasumichi Fukuda,* Hirosuke Furuta, Yoshie Kusama, Hiroyuki Ebisu, Yasuo Oomori, and Shiro Terashima*,†
Central Research Laboratories, Kyorin Pharmaceutical Company Ltd., Mitarai, Nogi, Tochigi 329-0114, J apan, and
Sagami Chemical Research Center, Nishi-Ohnuma, Sagamihara, Kanagawa 229-0012, J apan
Received November 25, 1998
The seco-Cl 3-methoxycarbonyl-2-trifluoromethylcyclopropapyrroloindole (MCTFCPI) deriva-
tives dl- and/or (S)-10 carrying various acyl moieties at the N6-position were synthesized along
with their prodrugs (S)-12, and their antitumor activity was evaluated. Among these derivatives,
AT-3510 [(S)-12m ], the novel prodrug MCTFCPI derivative carrying a 5-(7-methoxybenzofuran-
2-ylcarbonyl)aminoindole-2-carbonyl group at the N6-position, was found to exhibit more
excellent antitumor activity against human tumor xenografts than the clinical trial candidates
carzelesin (6) and KW-2189 (7) and cisplatin.
In tr od u ction
CPI systems, we first examined the synthesis and
evaluation of the MCTFCPI derivatives dl- and/or (S)-
11a ,b,f,i, and the prodrug (S)-13b bearing known acyl
moieties at the N6-position.9b On the basis of the results
obtained by these studies, our next efforts were the
synthesis and evaluation of the racemic or optically
active seco-Cl-MCTFCPI derivatives dl- and/or (S)-10c-
e,g,h ,j-w bearing novel acyl moieties at the N6-
position. Among dl- and/or (S)-10c-e,g,h ,j-w , dl- or
(S)-10k -n ,q,v were found to show more promising
antitumor activity. Subsequently, (S)-10k -n ,q,v were
masked with an N-methylpiperazinylcarbamoyl group
which had been introduced as the prodrug moiety of 7,
affording the optically active prodrugs (S)-12k -n ,q,v.
This sort of research strategy was taken by considering
the successful results for 1 and 2 in which 6 and 7 had
been developed based on the studies on their acyl and
prodrug moieties. As the results of our studies, AT-3510
[(S)-12m ], the novel prodrug MCTFCPI derivative car-
rying a 5-(7-methoxybenzofuran-2-ylcarbonyl)aminoin-
dole-2-carbonyl group at the N6-position, was found to
exhibit more excellent antitumor activity than all of the
CPI derivatives so far reported.6-9 Herein, we wish to
report on the synthesis and antitumor activity of dl-
and/or (S)-10c-e,g,h ,j-w and (S)-12k -n ,q,v including
(S)-12m which carries novel acyl moieties at the N6-
position.
CC-1065 (1),1 duocarmycin A (2),2 and duocarmycin
SA (3)3 (Chart 1), carrying a cyclopropapyrroloindole
(CPI) moiety as the common pharmacophore, are potent
antitumor antibiotics isolated from Streptomyces sp. The
CPI system has been recognized to be responsible for
their prominent cytotoxicity through sequence-selective
alkylation of double-strand DNA.4 Since unusual de-
layed lethality was observed for 1,5 various types of
congeners have been synthesized and evaluated to
explore less toxic analogues of 1, resulting in the
development of U-68415 (dl-4),4c U-73,975 (adozelesin)
(5),6 and U-80,244 (carzelesin) (6)7 as novel antitumor
agents showing no delayed toxicity. As for 2, synthetic
efforts have been devoted to the preparation of its
congeners, culminating in the exploration of KW-2189
(7)8 as a semisynthetic antitumor agent. These novel
antitumor agents 6 and 7 are presently under clinical
trials (Chart 1).
Recently, we have succeeded in the design and
synthesis of the racemic bis(methoxycarbonyl)CPI (MC2-
CPI) derivatives dl-9a ,b,f,i bearing two methoxycarbo-
nyl groups at the vicinal positions of the pyrrole ring.9a
Among dl-9a ,b,f,i, dl-9f,i were found to exhibit promis-
ing cytotoxicity (in vitro) and antitumor activity (in vivo)
against P388 murine leukemia. These results let us
develop a novel CPI system which can exhibit even more
prominent antitumor activity than dl-9f,i and also 6 and
7. Taking into account structural characteristics of the
CPI systems so far reported, we designed a novel CPI
system, the 3-methoxycarbonyl-2-trifluoromethylCPI
(MCTFCPI) system, which carries methoxycarbonyl and
trifluoromethyl groups at the vicinal positions of the
pyrrole ring.9b It is well-known that various fluorinated
drugs often show unique pharmacological properties.
Therefore, the antitumor activity of the novel MCTFCPI
derivatives dl- and/or (S)-11, their seco-type compounds
dl- and/or (S)-10, and the prodrugs (S)-12 and (S)-13
was expected to be quite promising (Chart 2). To explore
superiority of this novel MCTFCPI system to the known
Resu lts a n d Discu ssion
Ch em istr y. According to a preceding paper,9b we
completed the synthesis of the novel seco-Cl-MCTFCPI
derivatives dl- and/or (S)-10c-e,g,h ,j-w by coupling
the racemic or optically active phenol dl- or (S)-15 with
* To whom correspondence should be addressed.
† Sagami Chemical Research Center.
10.1021/jm980668c CCC: $18.00 © 1999 American Chemical Society
Published on Web 04/02/1999

AT-3510: Novel CPI Derivative
J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8 1449
Ch a r t 1
Ch a r t 2
various carboxylic acids 16c-e,g,h ,j-w . Among dl- or
(S)-10c-e,g,h ,j-w , dl- or (S)-10k -n ,q,v were found to
show more promising antitumor activity. Subsequently,
(S)-10k -n ,q,v were masked with an N-methylpiper-
azinylcarbamoyl group which had been introduced as
the prodrug moiety of 7, affording the prodrugs (S)-
12k -n ,q,v (Scheme 1).
tion of ethyl 5-aminoindole-2-carboxylate4c with appro-
priate carboxylic acids followed by alkaline hydrolysis.
Syntheses of the hitherto unknown carboxylic acids
16d ,e, 27b, 31, 35a ,b, and 41 were carried out as shown
in Schemes 2 and 3. The other carboxylic acids employed
in this work are commercially available or readily
obtainable according to the reported procedures.4c,9,10
Thus, 5,6,7-trimethoxybenzofuran-2-carboxylic acid
(16d ) was prepared from the phenol 17 by way of 3,4,5-
According to the reported method,4c 5-acylaminoin-
dole-2-carboxylic acids 16f-w were prepared by acyla-

1450 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8
Fukuda et al.
Sch em e 1a
3-carboxylate (30) was next prepared from the tyrosine
derivative 28 by employing the modified Bischler-
Napieralski procedure13 followed by dehydrogenation.
Syntheses of methyl 5-methoxy- and 5,6,7-trimethoxy-
isoquinoline-3-carboxylates (34a ,b) were achieved by
C-H bond insertion reaction of the nitrenes generated
from the vinyl azides 33a ,b.14 Thus, condensation of the
benzaldehyde 32a with methyl 2-azidoacetate produced
33a . Upon heating in refluxing xylene, 33a gave rise to
34a and the azirine 36a . The latter compound 36a was
further cyclized to 34a in refluxing 1,2-dichlorobenzene.
By employing the same procedure, 33b derived from the
benzaldehyde 32b was also successfully transformed to
34b. The resulting esters 26a ,b, 30, and 34a ,b gave the
corresponding carboxylic acids 27a ,b, 31, and 35a ,b by
alkaline hydrolyses. The synthesis of 5,6,7-trimethoxy-
cinnoline-3-carboxylic acid (41) was also achieved ac-
cording to the reported method.15 Thus, the reaction of
diazonium salt 38 derived from the aniline 37 with
enamino ester 39 cleanly provided 40, which upon
hydrolysis gave rise to 41.
a
(a) For c-e,g,h ,j-w , see Chart 2; (b) 3 M Hcl-AcOEt; (c)
EDCI, ArCO2H (16c-e,g,h ,j-w ), 42-89% (2 steps); (d) (i)
ClCO2PhNO2, Et3N, (ii) N-methylpiperazine, (iii) saturated HCl-
MeOH, 14-64% (3 steps).
Cytotoxicity a n d An titu m or Activity. The results
of cytotoxicity assay (in vitro) against P388 murine
leukemia and antitumor activity assay (in vivo) against
P388 murine leukemia and S180 murine sarcoma of the
MCTFCPI derivatives dl-11a ,b,f,i are summarized in
Table 1, along with those for dl-4,16 dl-9f,i, and dl-8
(DU-86)16 which is the parent compound of 7. It ap-
peared evident that the MCTFCPI derivatives dl-11b,f,i
exhibit promising antitumor activity against murine
leukemia and solid tumor.9b
Sch em e 2a
Aiming to definitely explore the fact that the MCT-
FCPI system is superior to the known CPI systems in
light of antitumor activity, we next evaluated optically
active (S)-11i and (S)-13b which bear the same acyl
moieties as 5 and the clinical trial candidate 7, respec-
tively, by comparing their antitumor activity with that
of 5 and 7.16 From the results shown in Table 2, it
appeared that the cytotoxicity against HeLaS3 human
uterine cervix carcinoma of (S)-11i is 10 times weaker
than that of 5 and that the prodrugs (S)-13b and 7
exhibit comparable weak cytotoxicity. On the other
hand, antitumor activity of (S)-11i and (S)-13b against
Colon 26 murine adenocarcinoma was found to be
comparable to that of 5 and 7, respectively.9b
a
(a) Hexamethylenetetramine, TFA, 90 °C, 69%; (b) ethyl bro-
moacetate, K2CO3, DMF, 80 °C, 62%; (c) 20% KOH, EtOH, 0 °C,
79%; (d) benzofuran-2-boric acid, Pd(PPh3)4, Et3N, DMF, 100 °C,
44%; (e) 20% KOH, MeOH, DMSO, 60 °C, 98%.
trimethoxysalicylaldehyde (18) according to the reported
method.12 In the synthesis of 18,11 direct formylation
of 17 by the Duff reaction was found to provide 18
exclusively. On the other hand, direct formylation of 17
with 1,1-dichlorodimethyl ether-TiCl4 was found to
exclusively give the benzaldehyde 21 regioisomeric to
18. This unusual reaction might take place by way of
formylation of the intermediate 20. The Suzuki coupling
of the 5-bromoindole 22 with benzofuran-2-boric acid
and subsequent alkaline hydrolysis furnished 16e
(Scheme 2).
With the results delineated above, the racemic or
optically active seco-Cl-MCTFCPI derivatives dl- or (S)-
10c-e,g,h ,j-w bearing novel acyl moieties at the N6-
position were next evaluated. They were subjected to
cytotoxicity assay (in vitro) against HeLaS3 human
uterine cervix carcinoma and antitumor activity assay
(in vivo) against Colon 26 murine adenocarcinoma. As
shown in Table 3, dl-10c,h having a methoxy group at
the C4-position on the indole ring exhibited significantly
less cytotoxicity than dl-10b,g which lack a methoxy
group at the same position. It appeared that a methoxy
group at the C4-position on the indole ring might
debilitate cytotoxicity due to the steric interaction in a
minor groove of duplex DNA. Cytotoxicity of the ben-
zofuran derivative (S)-10d was comparable to that of
dl-10b. It was also found that dl-10e lacking an amide
group between the indole and the benzofuran rings
shows less cytotoxicity than dl-10i, suggesting that the
amide group is essential for strong cytotoxicity. Cyto-
To the best of our knowledge, 5-, 7-, and 8-methoxy-
and 5,6,7-trimethoxyisoquinoline-3-carboxylic acids (35a,
31, 27b, and 35b) and 5,6,7-trimethoxycinnoline-3-
carboxylic acid (41) had not been reported to date.
Therefore, we examined their syntheses as shown in
Scheme 3. According to the reported method,12 the
synthesis of methyl 6-methoxyisoquinoline-3-carboxy-
late (26a ) was first attempted. The Bischler-Napier-
alski reaction of 3-methoxyphenylalanine (24) and
subsequent dehydrogenation afforded 26a along with a
small amount of unreported methyl 8-methoxyisoquino-
line-3-carboxylate (26b). Methyl 7-methoxyisoquinoline-

AT-3510: Novel CPI Derivative
J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8 1451
Sch em e 3a
a
(a) (i) HCHO, (ii) HCl, MeOH; (b) 10% Pd-C, xylene, reflux, 9.6% (26a from 24), 0.6% (26b from 24), 8% (30 from 28); (c) 20% KOH,
MeOH, 79% (for 27a ), 76% (for 27b), 77% (for 31), 73% (for 35a ), 83% (for 35b), 77% (for 41); (d) (i) (COCl)2, CH2Cl2, (ii) FeCl3, (iii)
MeOH, H2SO4; (e) methyl azidoacetate, NaOMe, MeOH, 63% (for 33a ), 41% (for 33b); (f) xylene, reflux; (g) 1,2-dichlorobenzene, reflux,
49% (for 34a ), 41% (for 34b); (h) NaNO2, concd HCl, NaBF4, 81%; (i) MeCN, 80 °C, 93%.
Ta ble 1. Cytotoxicity of U-68415 (dl-4), the MC2CPI
Derivatives dl-9f,i, the MCTFCPI Derivatives dl-10a ,b,f,i, and
DU-86 (dl-8) against P388 Murine Leukemia Cells and Their in
Vivo Antitumor Activity against P388 Murine Leukemia Cells
and S180 Murine Sarcoma Cells
Ta ble 2. Cytotoxicity of Adozelesin (5), KW-2189 (7), the
MCTFCPI Derivative (S)-11i, and the Prodrug of the MCTFCPI
Derivative (S)-13b against HeLaS3 Human Uterine Cervix
Carcinoma Cells and Their in Vivo Antitumor Activity against
Colon 26 Murine Adenocarcinoma Cells
IC50
P388 ILS (%)b
(mg/kg)
S180 TGI (%)c
(mg/kg)
IC50
TGI (%)
(mg/kg)b
TGI50
compd
(ng/mL)a
compd
(ng/mL)a
(mg/kg)c
MTDd/TGI50
dl-11a
dl-11b
dl-11f
dl-11i
dl-9f
dl-9i
0.23
0.24
0.86
0.53
0.31
0.66
0.34
0.028
69 (0.125)
94 (0.125)
2/2d (0.25)
2/2d (0.25)
102 (0.125)
79 (0.125)
80 (0.125)
210 (0.125)
54 (0.25)
92 (0.5)
84 (0.25)
83 (0.25)
44 (0.5)
26 (0.5)
81 (0.5)
86 (0.125)
(S)-11i
5
(S)-13b
7
0.365
0.0364
18.8
85 (0.177)
79 (0.0884)
93 (0.500)
90 (0.707)
0.0410
0.0444
0.0429
0.209
4.3
2.0
11.7
3.4
18.1
a
Drug concentration required to inhibit the growth of HeLaS3
b
cells by 50%. Percentage tumor growth inhibition as compared
dl-8
dl-4
with the untreated group. c Drug concentration required to inhibit
d
the tumor growth by 50%. Maximum dose within 10% body
weight loss.
a
Drug concentration required to inhibit the growth of P388
b
murine leukemia cells by 50%. Percentage increase in life span
as compared with the untreated group. c Percentage tumor growth
activity assay (in vivo) against Colon 26 murine adeno-
carcinoma. From the results shown in Table 4, all these
prodrugs showed excellent antitumor activity against
Colon 26 murine adenocarcinoma. Among these pro-
drugs, (S)-12m ,q were found to exhibit more excellent
antitumor activity than the others. Accordingly, both
(S)-12m ,q were subjected to antitumor activity assay
against human tumor xenografts for further evaluation.
As shown in Table 5, (S)-12m showed better antitumor
activity against human tumor xenografts than (S)-12q,
the clinical trial candidates 616 and 7, and the clinically
widely used anticancer agent cisplatin.
d
inhibition as compared with the untreated group. Cured mice
(>60-day survivors).
toxicity and antitumor activity of (S)-10j-n ,r -v car-
rying a methoxy or trimethoxy group(s) on the benzo-
furan and isoquinolinerings,respectively,werecomparable
to those of dl-10i,q which have no methoxy group on
the benzofuran and isoquinoline rings, respectively.
Comparing with dl-10o and (S)-10v, dl-10p and dl-10w ,
to which a nitrogen atom is introduced to the C1-
position, exhibited less cytotoxicity. Summing up the
above results, it appeared evident that almost all the
seco-Cl derivatives dl- or (S)-10d ,e,g-v tested exhibited
promising antitumor activity.
Con clu sion
Since the seco-Cl derivatives dl- or (S)-10k -n ,q,v
showed more promising antitumor activity, the optically
active prodrugs (S)-12k -n ,q,v were prepared from (S)-
10k -n ,q,v by masking with an N-methylpiperazinyl-
carbamoyl group as shown in Scheme 1. These novel
prodrugs (S)-12k -n ,q ,v were subjected to antitumor
As described above, we have succeeded in the syn-
thesis of the MCTFCPI derivatives dl- and/or (S)-
11a ,b,f,i, the seco-Cl-MCTFCPI derivatives dl- or (S)-
10c-e,g,h ,j-w carrying novel acyl moieties at the N6-
position, and their prodrugs (S)-12k -n ,q,v. On the
basis of these studies, the novel prodrug (S)-12m was

1452 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8
Fukuda et al.
Ta ble 3. Cytotoxicity of the Seco-Cl-MCTFCPI Derivatives dl- or (S)-10b-e,g-w against HeLaS3 Human Uterine Cervix Carcinoma
Cells and Their in Vivo Antitumor Activity against Colon 26 Murine Adenocarcinoma Cells
dl- or
IC50
TGI (%)
(mg/kg)c
(S)-10a
Ar
X
Y
R
(ng/mL)b
b*
c*
d
NH
NH
O
5,6,7-(OMe)3
4,5,6-(OMe)3
5,6,7-(OMe)3
0.25
32
0.12
NTd
NT
75 (0.5)
e*
3.6
84 (1.0)
g*
h *
i*
j
k
l
m
n
o*
p *
q*
r
NH
NH
O
O
O
O
O
O
CH
CH
N
N
N
N
N
N
N
5,6,7-(OMe)3
4,5,6-(OMe)3
H
4-OMe
5-OMe
6-OMe
7-OMe
5,6,7-(OMe)3
H
0.20
0.94
0.53
0.87
0.064
0.12
0.51
0.17
0.22
1.5
0.24
0.20
0.18
0.11
0.51
0.20
6.5
83 (0.25)
95 (0.5)
85 (0.5)
83 (0.5)
94 (0.5)
94 (0.5)
96 (0.5)
74 (0.125)
84 (0.5)
84 (0.5)
82 (0.25)
67 (0.125)
90 (0.25)
82 (0.25)
90 (0.25)
93 (0.25)
NT
CH
N
H
H
CH
CH
CH
CH
CH
CH
N
5-OMe
6-OMe
7-OMe
8-OMe
5,6,7-(OMe)3
5,6,7-(OMe)3
s
t
u
v
w *
a
b
An asterisk (/) indicates the racemic form. Drug concentration required to inhibit the growth of HeLaS3 cells by 50%. c Colon 26
(106/mouse) cells were inoculated sc into male CDF1 mice on day 0. Drugs were administered iv on day 7. Percentage tumor growth
inhibition as compared with the untreated group. NT, not tested.
d
Ta ble 4. In Vivo Antitumor Activity of the Prodrugs of the
7 and the clinically widely used anticancer agent
Seco-Cl-MCTFCPI Derivatives (S)-12k -n ,q,v against Colon 26
cisplatin. Further evaluation is being undertaken to
confirm whether (S)-12m can be selected as a potential
candidate for clinical trial.
Murine Adenocarcinoma
(S)-12
TGI (%) (mg/kg)a
TGI50 (mg/kg)b
MTDc/TGI50
k
l
m
n
q
v
86 (1.0)
89 (0.5)
95 (2.0)
90 (0.25)
93 (0.5)
89 (0.5)
0.148
0.108
0.265
0.0533
0.082
0.130
6.8
4.6
7.6
4.5
6.1
3.9
Exp er im en ta l Section
All melting points were determined with a Yamato MP-500
melting point apparatus and are uncorrected. Measurements
of optical rotations were carried out using a J ASCODIP-360
automatic digital polarimeter. Infrared (IR) spectra were
recorded on a J ASCO FT/IR-5300 spectrometer. 1H NMR
spectra were measured with a J EOL J NM-EX-400 (400 MHz)
spectrometer. The chemical shifts are expressed in parts per
million (δ-value) downfield from tetramethylsilane, using
tetramethylsilane (δ ) 0) and/or residual solvents such as
chloroform (δ ) 7.26) and benzene (δ ) 7.20) as an internal
standard. Splitting patterns are indicated as s, singlet; d,
doublet; t, triplet; q, quartet; m, multiplet; br, broad peak.
Measurements of mass spectra were performed with a Hitachi
M-2000 mass spectrometer. Data for elemental analysis are
within (0.3% of theoretical values and were determined by a
Yanaco CHN corder MT-5. Unless otherwise noted, all the
experiments were carried out using anhydrous solvents under
an atmosphere of dry argon. Especially, tetrahydrofuran and
diethyl ether (ether) were distilled from sodium benzophenone
ketyl. Throughout this work, Merck precoated TLC plates
(silica gel 60 F254, 0.25 mm; Art. 5715) were used for thin layer
chromatographic (TLC) analyses. Wako Gel C-200 and C-300
were used as an adsorbent for flash column chromatography.
To minimize the health risks posed by these potent cytotoxic
compounds to analytical service personnel of our laboratory
and to allow preparation of only the very limited quantities
needed for testing, infrared spectra and combustion elemental
analyses were not obtained on the final analogues except for
(S)-12m .4c
a
Percentage tumor growth inhibition as compared with the
b
untreated group. Drug concentration required to inhibit the
tumor growth by 50%. c Maximum dose within 10% body weight
loss.
Ta ble 5. In Vivo Antitumor Activity of Carzelesin (6),
KW-2189 (7), Cisplatin, and the Prodrugs of the
Seco-Cl-MCTFCPI Derivatives (S)-12m ,q against Human
Tumor Xenograftsa
max TGI (%)b
dose
NUGC-3
HCT-116 DLD-1
WiDr
compd
(mg/kg) (stomach)
(colon)
(colon) (colon)
(S)-12m
(S)-12q
6
3.13
100
97
90
77d
82
73
34
83
76
79
65
25
86
0.845
0.584
1.00
NTe
56
98
7
91c
59
44
cisplatin
9.81
87
a
Tumor fragments (2-3 mm3) were implanted sc into female
BALB/cA J cl-nu mice on day 0. Drugs were administered single
iv when tumor volume reached about 100 mm3. Percentage of
b
maximum tumor growth inhibition as compared with the un-
treated group. c Dose was 0.716 mg/kg. Dose was 0.800 mg/kg.
d
e NT, not tested.
found to exhibit prominent antitumor activity against
murine solid tumor. Moreover, it should be noted that
(S)-12m shows better antitumor activity against human
tumor xenografts than the clinical trial candidates 6 and
dl-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth yl-
6-(4,5,6-tr im eth oxy-1H-in dol-2-ylcar bon yl)-1,4,5,6-tetr ah y-
d r op yr r olo[3,2-e]in d ole-3-ca r boxyla te (d l-10c). A solution
of dl-14 (10.3 mg, 23 µmol) in 3 M HCl-AcOEt (0.4 mL) was

AT-3510: Novel CPI Derivative
J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8 1453
mg, 73%) was prepared from (S)-14 (11.2 mg, 25 µmol) and
stirred at room temperature for 2 h. Concentration of the
mixture in vacuo gave the crude hydrochloride dl-15 as a pale
yellow powder, which was directly added to a solution of 16c
(5.8 mg, 23 µmol) and 1-[3-(dimethylamino)propyl]-3-ethylcar-
bodiimide hydrochloride (EDCI) (13.2 mg, 69 µmol) in DMF
(0.25 mL). The mixture was stirred at room temperature for
overnight. After dilution with AcOEt and water, the mixture
was washed with 5% NaHCO3 solution, dried over anhydrous
Na2SO4, filtered, and then concentrated in vacuo. Flash
chromatography (CHCl3:MeOH ) 15:1) of the residue gave dl-
10c as pale yellow crystals (10.3 mg, 77%). 1H NMR (CDCl3 +
DMSO-d6): δ 3.35 (t, J ) 10.7 Hz, 1H), 3.86-3.89 (m, 1H),
3.88, 3.89, 3.98, 4.15 (sx4, each 3H), 4.44 (m, 1H), 4.56 (t, J )
9.8 Hz, 1H), 4.74 (d, J ) 10.3 Hz, 1H), 6.68 (s, 1H), 8.04 (brs,
1H), 9.08 (s, 1H), 9.85 (s, 1H), 11.40 (brs, 1H). MS (FAB) m/z:
582 (MH+). HRMS (FAB) for C26H24ClF3N3O7 (MH+): calcd,
582.1255; found, 582.1279. Other racemic and/or optically
active seco-Cl-MCTFCPI derivatives dl- and/or (S)-10b-w
were prepared in the same manner as described above by
employing dl- and/or (S)-15 prepared from dl- and/or (S)-14
and 16b-w .
(S)-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth -
yl-6-(5,6,7-t r im et h oxyb en zofu r a n -2-ylca r b on yl)-1,4,5,6-
tetr a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te [(S)-10d ].
This compound (S)-10d (10.5 mg, 72%) was prepared from (S)-
14 (11.2 mg, 25 µmol) and 16d (6.3 mg, 25 µmol). [R]D23 ) +18°
(c ) 0.20, THF). 1H NMR (CDCl3): δ 3.36 (t, J ) 10.8 Hz, 1H),
3.85-3.95 (m, 1H), 3.91, 3.95, 3.97, 4.28 (sx4, each 3H), 4.46-
4.51 (m, 1H), 4.65 (dd, J ) 10.8 Hz, 8.8 Hz, 1H), 4.90 (d, J )
10.8 Hz, 1H), 6.83 (s, 1H), 7.68 (s, 1H), 8.54 (s, 1H), 9.72 (brs,
1H), 11.17 (brs, 1H). MS (FAB) m/z: 583 (MH+). HRMS (FAB)
for C26H23ClF3N2O8 (MH+): calcd, 583.1095; found, 583.1074.
16j (8.8 mg, 25 µmol). [R]D ) +57° (c ) 0.20, THF). 1H NMR
25
(DMSO-d6): δ 3.53 (dd, J ) 10.8 Hz, 8.8 Hz, 1H), 3.82-3.92
(m, 1H), 3.88, 3.97 (sx2, each 3H), 4.25-4.35 (m, 1H), 4.54 (d,
J ) 10.8 Hz, 1H), 4.72 (t, J ) 10.8 Hz, 1H), 6.89 (d, J ) 7.8
Hz, 1H), 7.18 (s, 1H), 7.31 (d, J ) 8.8 Hz, 1H), 7.44 (t, J ) 8.3
Hz, 1H), 7.49 (d, J ) 8.8 Hz, 1H), 7.58-7.64 (m, 1H), 7.79 (s,
1H), 7.95 (brs, 1H), 8.21 (s, 1H), 10.39 (s, 1H), 10.59 (brs, 1H),
11.74 (s, 1H), 13.10 (brs, 1H). MS (FAB) m/z: 681 (MH+).
HRMS (FAB) for C33H25ClF3N4O7 (MH+): calcd, 681.1364;
found, 681.1388.
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(5-m et h -
oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10k ]. This compound (S)-10k (10.7
mg, 63%) was prepared from (S)-14 (11.2 mg, 25 µmol) and
16k (8.8 mg, 25 µmol). [R]D25 ) +44° (c ) 0.20, THF). 1H NMR
(DMSO-d6): δ 3.46 (dd, J ) 10.8 Hz, 7.8 Hz, 1H), 3.78-3.84
(m, 1H), 3.77, 3.81 (sx2, each 3H), 4.18-4.26 (m, 1H), 4.47 (d,
J ) 10.8 Hz, 1H), 4.65 (t, J ) 10.8 Hz, 1H), 7.02 (dd, J ) 8.8
Hz, 2.0 Hz, 1H), 7.11 (s, 1H), 7.25 (d, J ) 2.9 Hz, 1H), 7.42 (d,
J ) 8.8 Hz, 1H), 7.53-7.57 (m, 2H), 7.62 (s, 1H), 7.89 (brs,
1H), 8.14 (s, 1H), 10.38 (s, 1H), 10.53 (brs, 1H), 11.67 (s, 1H),
13.04 (brs, 1H). MS (FAB) m/z: 681 (MH+). HRMS (FAB) for
C
33H25ClF3N4O7 (MH+): calcd, 681.1364; found, 681.1382.
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(6-m et h -
oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10l]. This compound (S)-10l (13.7
mg, 81%) was prepared from (S)-14 (11.2 mg, 25 µmol) and
26
16l (8.8 mg, 25 µmol). [R]D ) +42° (c ) 0.20, THF). 1H NMR
(DMSO-d6): δ 3.53 (dd, J ) 10.8 Hz, 8.8 Hz, 1H), 3.82-3.92
(m, 1H), 3.87, 3.89 (sx2, each 3H), 4.25-4.28 (m, 1H), 4.54 (d,
J ) 9.8 Hz, 1H), 4.70-4.75 (m, 1H), 7.00 (dd, J ) 8.8 Hz, 2.0
Hz, 1H), 7.18 (s, 1H), 7.28 (d, J ) 2.0 Hz, 1H), 7.49 (d, J ) 8.8
Hz, 1H), 7.60 (dd, J ) 8.8 Hz, 2.0 Hz, 1H), 7.66-7.74 (m, 2H),
7.95 (brs, 1H), 8.20 (s, 1H), 10.34 (s, 1H), 10.59 (s, 1H), 11.73
(s, 1H), 13.11 (s, 1H). MS (FAB) m/z: 681 (MH+). HRMS (FAB)
for C33H25ClF3N4O7 (MH+): calcd, 681.1364; found, 681.1388.
d l-Meth yl 6-(Ben zofu r a n -2-yl-1H-in d ol-2-ylca r bon yl)-
4-ch lor om eth yl-8-h yd r oxy-2-tr iflu or om eth yl-1,4,5,6-tet-
r a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te (d l-10e). This
compound dl-10e (10.6 mg, 76%) was prepared from dl-14 (10.3
mg, 23 µmol) and 16e (6.4 mg, 23 µmol). 1H NMR (CDCl3
+
DMSO-d6): δ 3.37 (t, J ) 10.3 Hz, 1H), 3.90 (dd, J ) 10.3 Hz,
2.9 Hz, 1H), 3.98 (s, 3H), 4.47 (m, 1H), 4.59 (t, J ) 10.3 Hz,
1H), 4.78 (d, J ) 10.7 Hz, 1H), 7.00 (s, 1H), 7.14 (s, 1H), 7.21-
7.29 (m, 2H), 7.52-7.59 (m, 3H), 7.81 (dd, J ) 8.8 Hz, 2.0 Hz,
1H), 8.02 (br, 1H), 8.27 (s, 1H), 9.17 (s, 1H), 10.31 (s, 1H), 11.52
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(7-m et h -
oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10m ]. This compound (S)-10m
(11.8 mg, 76%) was prepared from (S)-14 (10.3 mg, 23 µmol)
(br, 1H). MS (FAB) m/z: 608 (MH+). HRMS (FAB) for C31H22
-
ClF3N3O5 (MH+): calcd, 608.1200; found, 608.1205.
24
1
dl-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth yl-
6-[5-[(5,6,7-tr im eth oxy-1H-in d ol-2-ylca r bon yl)a m in o]-1H-
in dol-2-ylcar bon yl]-1,4,5,6-tetr ah ydr opyr r olo[3,2-e]in dole-
3-ca r boxyla te (d l-10g). This compound dl-10g (13.2 mg, 78%)
was prepared from dl-14 (10.3 mg, 23 µmol) and 16g (9.4 mg,
23 µmol). 1H NMR (CDCl3 + DMSO-d6): δ 3.36 (t, J ) 9.8 Hz,
1H), 3.89 (m, 1H), 3.92, 3.95, 3.98, 4.10 (sx4, each 3H), 4.45
(m, 1H), 4.57 (t, J ) 9.8 Hz, 1H), 4.77 (d, J ) 9.8 Hz, 1H),
6.86 (s, 1H), 7.06 (s, 1H), 7.17 (s, 1H), 7.47 (d, J ) 8.8 Hz,
1H), 7.53 (dd, J ) 8.8 Hz, 2.0 Hz, 1H), 8.02 (s, 1H), 8.20 (s,
1H), 9.07 (s, 1H), 9.11 (s, 1H), 9.87 (s, 1H), 9.91 (s, 1H), 11.39
and 16m (8.1 mg, 23 µmol). [R]D ) +53° (c ) 0.36, THF). H
NMR (DMSO-d6): δ ) 3.53 (dd, J ) 10.5 Hz, 8.3 Hz, 1H),
3.80-3.90 (m, 1H), 3.88, 4.00 (sx2, each 3H), 4.26-4.30 (m,
1H), 4.53 (d, J ) 10.5 Hz, 1H), 4.72 (t, J ) 9.3 Hz, 1H), 7.10
(d, J ) 8.1 Hz, 1H), 7.19 (s, 1H), 7.29 (d, J ) 8.1 Hz, 1H), 7.37
(d, J ) 8.1 Hz, 1H), 7.49 (d, J ) 8.8 Hz, 1H), 7.59 (dd, J ) 8.8
Hz, 1.7 Hz, 1H), 7.76 (s, 1H), 7.95 (s, 1H), 8.19 (s, 1H), 10.43
(s, 1H), 10.60 (s, 1H), 11.75 (s, 1H), 13.12 (s, 1H). MS (FAB)
m/z: 681 (MH+). HRMS (FAB) for C33H25ClF3N4O7 (MH+):
calcd, 681.1364; found, 681.1327.
(S)-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth -
yl-6-[5-[(5,6,7-tr im eth oxyben zofu r an -2-ylcar bon yl)am in o]-
1H-in d ol-2-ylca r bon yl]-1,4,5,6-tetr a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10n ]. This compound (S)-10n (8.7
mg, 59%) was prepared from (S)-14 (9.0 mg, 20 µmol) and 16n
(s, 1H). MS (FAB) m/z: 740 (MH+). HRMS (FAB) for C35H30
-
ClF3N5O8 (MH+): calcd, 740.1735; found, 740.1745.
dl-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth yl-
6-[5-[(4,5,6-tr im eth oxy-1H-in d ol-2-ylca r bon yl)a m in o]-1H-
in dol-2-ylcar bon yl]-1,4,5,6-tetr ah ydr opyr r olo[3,2-e]in dole-
3-ca r boxyla te (d l-10h ). This compound dl-10h (8.5 mg, 50%)
was prepared from dl-14 (10.3 mg, 23 µmol) and 16h (9.4 mg,
23 µmol). 1H NMR (CDCl3 + DMSO-d6): δ 3.36 (t, J ) 9.8 Hz,
1H), 3.81-3.93 (m, 1H), 3.877, 3.879, 3.98, 4.15 (sx4, each 3H),
4.45 (m, 1H), 4.57 (t, J ) 10.3 Hz, 1H), 4.77 (d, J ) 10.3 Hz,
1H), 6.68 (s, 1H), 7.06 (s, 1H), 7.35 (s, 1H), 7.47 (d, J ) 8.8
Hz, 1H), 7.54 (d, J ) 8.8 Hz, 1H), 8.03 (s, 1H), 8.21 (s, 1H),
8.99 (s, 1H), 9.15 (s, 1H), 10.02 (s, 1H), 10.09 (s, 1H), 11.44 (s,
25
(8.2 mg, 20 µmol). [R]D ) +55° (c ) 0.20, THF). 1H NMR
(DMSO-d6): δ 3.53 (dd, J ) 10.8 Hz, 8.8 Hz, 1H), 3.82-3.92
(m, 1H), 3.81, 3.86, 3.88, 4.17 (sx4, each 3H), 4.25-4.35 (m,
1H), 4.54 (d, J ) 10.8 Hz, 1H), 4.72 (t, J ) 10.8 Hz, 1H), 7.08
(s, 1H), 7.18 (s, 1H), 7.49 (d, J ) 8.8 Hz, 1H), 7.56 (dd, J ) 8.8
Hz, 2.0 Hz, 1H), 7.69 (s, 1H), 7.95 (brs, 1H), 8.17 (s, 1H), 10.32
(s, 1H), 10.60 (brs, 1H), 11.75 (s, 1H), 13.10 (brs, 1H). MS
(FAB) m/z: 741 (MH+). HRMS (FAB) for C35H29ClF3N4O9
(MH+): calcd, 741.1575; found, 741.1568.
1H). MS (FAB) m/z: 740 (MH+). HRMS (FAB) for C35H30
-
d l-Meth yl 4-Ch lor om eth yl-8-h yd r oxy-6-[5-[(n a p h th a -
len -2-ylcar bon yl)am in o]-1H-in dol-2-ylcar bon yl]-2-tr iflu o-
r om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]in d ole-3-ca r -
boxyla te (d l-10o). This compound dl-10o (10.1 mg, 80%) was
prepared from dl-14 (8.5 mg, 19 µmol) and 16o (6.3 mg, 19
ClF3N5O8 (MH+): calcd, 740.1735; found, 740.1774.
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(4-m et h -
oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10j]. This compound (S)-10j (12.5
1
µmol). H NMR (CDCl3 + DMSO-d6): δ 3.37 (t, J ) 10.3 Hz,

1454 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8
Fukuda et al.
25
1H), 3.89 (dd, J ) 10.7 Hz, 2.9 Hz, 1H), 3.98 (s, 3H), 4.44 (m,
1H), 4.57 (t, J ) 9.8 Hz, 1H), 4.76 (d, J ) 10.7 Hz, 1H), 7.07
(s, 1H), 7.50 (d, J ) 8.8 Hz, 1H), 7.55-7.61 (m, 3H), 7.90-
8.00 (m, 4H), 8.07 (d, J ) 8.8 Hz, 1H), 8.25 (s, 1H), 8.54 (s,
1H), 9.24 (s, 1H), 9.36 (s, 1H), 10.22 (s, 1H), 11.60 (br, 1H).
MS (FAB) m/z: 661 (MH+). HRMS (FAB) for C34H25ClF3N4O5
(MH+): calcd, 661.1466; found, 661.1442.
(7.3 mg, 20 µmol). [R]D ) +71° (c)0.20, THF). 1H NMR
(DMSO-d6): δ 3.53 (dd, J ) 9.8 Hz, 7.8 Hz, 1H), 3.83-3.93
(m, 1H), 3.88, 3.98 (sx2, each 3H), 4.25-4.35 (m, 1H), 4.54 (d,
J ) 9.8 Hz, 1H), 4.73 (t, J ) 9.8 Hz, 1H), 7.18 (s, 1H), 7.49 (d,
J ) 8.8 Hz, 1H), 7.55 (dd, J ) 8.8 Hz, 2.9 Hz, 1H), 7.68-7.76
(m, 2H), 7.95 (brs, 1H), 8.18 (d, J ) 8.8 Hz, 1H), 8.37 (d, J )
2.0 Hz, 1H), 8.65 (s, 1H), 9.37 (s, 1H), 10.59 (brs, 1H), 10.62
(s, 1H), 11.71 (s, 1H), 13.10 (brs, 1H). MS (FAB) m/z: 692
(MH+). HRMS (FAB) for C34H26ClF3N5O6 (MH+): calcd,
692.1524; found, 692.1557.
d l-Meth yl 4-Ch lor om eth yl-8-h yd r oxy-6-[5-[(qu in olin -
3-y lc a r b o n y l)a m i n o ]-1H -i n d o l-2-y lc a r b o n y l]-2-t r i -
flu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]in d ole-3-
ca r boxyla te (d l-10p ). This compound dl-10p (6.4 mg, 42%)
was prepared from dl-14 (10.3 mg, 23 µmol) and 16p (7.6 mg,
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(8-m et h -
oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10u ]. This compound (S)-10u (4.0
mg, 52%) was prepared from (S)-14 (4.9 mg, 11 µmol) and 16u
1
23 µmol). H NMR (CDCl3 + DMSO-d6): δ ) 3.37 (t, J ) 10.3
Hz, 1H), 3.89 (dd, J ) 10.8 Hz, 2.9 Hz, 1H), 3.98 (s, 3H), 4.44
(m, 1H), 4.58 (t, J ) 9.8 Hz, 1H), 4.77 (d, J ) 10.7 Hz, 1H),
7.07 (s, 1H), 7.49 (d, J ) 8.8 Hz, 1H), 7.61 (d, J ) 9.8 Hz, 1H),
7.66 (d, J ) 7.3 Hz, 1H), 7.83 (t, J ) 7.3 Hz, 1H), 7.97-8.01
(m, 1H), 8.18 (d, J ) 8.3 Hz, 1H), 8.25 (s, 1H), 8.87 (s, 1H),
9.23 (s, 1H), 9.53 (s, 1H), 9.77 (br, 1H), 10.12 (br, 1H), 10.79
(br, 1H), 11.51 (br, 1H). MS (FAB) m/z: 662 (MH+). HRMS
(FAB) for C33H24ClF3N5O5 (MH+): calcd, 662.1418; found,
662.1450.
25
(4.0 mg, 11 µmol). [R]D ) +53° (c ) 0.20, THF). 1H NMR
(DMSO-d6): δ 3.52 (t, J ) 9.8 Hz, 1H), 3.82-3.95 (m, 1H),
3.88, 4.08 (sx2, each 3H), 4.25-4.35 (m, 1H), 4.54 (d, J ) 10.8
Hz, 1H), 4.71 (t, J ) 9.8 Hz, 1H), 7.18 (brs, 1H), 7.28 (d, J )
7.8 Hz, 1H), 7.50 (d, J ) 8.8 Hz, 1H), 7.73 (d, J ) 8.8 Hz, 1H),
7.78 (d, J ) 7.8 Hz, 1H), 7.83 (d, J ) 7.8 Hz, 1H), 7.95 (brs,
1H), 8.38 (brs, 1H), 8.66 (s, 1H), 9.60 (s, 1H), 10.60 (brs, 1H),
10.70 (s, 1H), 11.72 (s, 1H), 13.10 (brs, 1H). MS (FAB) m/z:
692 (MH+). HRMS (FAB) for C34H26ClF3N5O6 (MH+): calcd,
692.1524; found, 692.1570.
d l- a n d (S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-
[(isoqu in olin -3-ylcar bon yl)am in o]-1H-in dol-2-ylcar bon yl]-
2-tr iflu or om eth yl-1,4,5,6-tetr a h yd r op yr r olo[3,2-e]in d ole-
3-ca r boxyla te [d l- a n d (S)-10q]. These compounds dl-10q
(8.3 mg, 54%) and (S)-10q (10.3 mg, 68%) were prepared from
dl- and (S)-14 (each 10.3 mg, 23 µmol) and 16q (each 7.6 mg,
23 µmol), respectively. dl-10q: 1H NMR (CDCl3 + DMSO-d6):
δ 3.37 (t, J ) 8.3 Hz, 1H), 3.87-3.98 (m, 1H), 3.98 (s, 3H),
4.44 (m, 1H), 4.58 (t, J ) 8.3 Hz, 1H), 4.77 (d, J ) 10.7 Hz,
1H), 7.09 (s, 1H), 7.53 (d, J ) 8.8 Hz, 1H), 7.60 (d, J ) 8.8 Hz,
1H), 7.75 (t, J ) 8.3 Hz, 1H), 7.82 (t, J ) 8.3 Hz, 1H), 8.01-
8.06 (m, 2H), 8.10 (d, J ) 8.3 Hz, 1H), 8.39 (s, 1H), 8.74 (s,
1H), 9.22 (brs, 1H), 9.26 (s, 1H), 10.19 (brs, 1H), 10.31 (s, 1H),
11.56 (brs, 1H). MS (FAB) m/z: 662 (MH+). HRMS (FAB) for
dl-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth yl-
6-[5-[(5,6,7-tr im eth oxyisoqu in olin -3-ylca r bon yl)a m in o]-
1H-in d ol-2-ylca r bon yl]-1,4,5,6-tetr a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te (d l-10v). This compound dl-10v (15.4
mg, 89%) was prepared from dl-14 (10.3 mg, 23 µmol) and 16v
1
(9.7 mg, 23 µmol). H NMR (CDCl3 + DMSO-d6): δ 3.37 (t, J
) 9.8 Hz, 1H), 3.89 (m, 1H), 3.98, 4.05, 4.07, 4.12 (sx4, each
3H), 4.44 (m, 1H), 4.58 (m, 1H), 4.77 (d, J ) 7.3 Hz, 1H), 7.08
(s, 1H), 7.17 (s, 1H), 7.52 (d, J ) 6.8 Hz, 1H), 7.60 (m, 1H),
8.00 (brs, 1H), 8.37 (s, 1H), 8.87 (s, 1H), 9.06 (s, 1H), 9.23 (s,
1H), 10.25 (br, 1H), 10.92 (br, 1H), 11.58 (br, 1H). MS (FAB)
m/z: 752 (MH+). HRMS (FAB) for C36H30ClF3N5O8 (MH+):
calcd, 752.1735; found, 752.1759.
C
33H24ClF3N5O5 (MH+): calcd, 662.1418; found, 662.1426. (S)-
24
1
10q: [R]D ) +63° (c ) 0.24, THF). The H NMR spectrum of
(S)-10q was identical to that described above.
dl-Meth yl 4-Ch lor om eth yl-8-h ydr oxy-2-tr iflu or om eth yl-
6-[5-[(5,6,7-tr im eth oxycin n olin -3-ylca r bon yl)a m in o]-1H-
in dol-2-ylcar bon yl]-1,4,5,6-tetr ah ydr opyr r olo[3,2-e]in dole-
3-ca r boxyla te (d l-10w ). This compound dl-10w (13.4 mg,
77%) was prepared from dl-14 (10.3 mg, 23 µmol) and 16w
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(5-m et h -
oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10r ]. This compound (S)-10r (11.1
mg, 64%) was prepared from (S)-14 (11.2 mg, 25 µmol) and
16r (9.0 mg, 25 µmol). [R]D25 ) +66° (c ) 0.20, THF). 1H NMR
(DMSO-d6): δ 3.53 (t, J ) 10.8 Hz, 1H), 3.84-3.95 (m, 1H),
3.88, 4.08 (sx2, each 3H), 4.25-4.35 (m, 1H), 4.54 (d, J ) 10.8
Hz, 1H), 4.73 (t, J ) 10.8 Hz, 1H), 7.19 (s, 1H), 7.37 (d, J )
7.8 Hz, 1H), 7.50 (d, J ) 8.8 Hz, 1H), 7.73 (dd, J ) 8.8 Hz, 2.0
Hz, 1H), 7.78 (t, J ) 7.8 Hz, 1H), 7.85 (d, J ) 7.8 Hz, 1H),
7.95 (brs, 1H), 8.38 (d, J ) 2.0 Hz, 1H), 8.83 (s, 1H), 9.44 (s,
1H), 10.60 (brs, 1H), 10.68 (s, 1H), 11.72 (s, 1H), 13.10 (brs,
1
(9.7 mg, 23 µmol). H NMR (CDCl3 + DMSO-d6): δ ) 3.41 (t,
J ) 10.3 Hz, 1H), 3.91 (d, J ) 10.3 Hz, 1H), 3.99, 4.090, 4.094,
4.15 (sx4, each 3H), 4.45 (m, 1H), 4.60 (t, J ) 10.3 Hz, 1H),
4.78 (d, J ) 10.7 Hz, 1H), 7.08 (s, 1H), 7.53 (d, J ) 8.8 Hz,
1H), 7.60 (d, J ) 8.8 Hz, 1H), 7.68 (s, 1H), 8.06 (brs, 1H), 8.36
(s, 1H), 8.97 (s, 1H), 9.39 (br, 1H), 10.44 (br, 1H), 10.47 (s,
1H), 11.67 (br, 1H). MS (FAB) m/z: 753 (MH+). HRMS (FAB)
for C35H29ClF3N6O8 (MH+): calcd, 753.1687; found, 753.1679.
(S)-Meth yl 4-Ch lor om eth yl-6-[5-[(5-m eth oxyben zofu r an -
2-y lc a r b o n y l)a m i n o ]-1H -i n d o l-2-y lc a r b o n y l]-8-[(4-
m et h ylp ip er a zin -1-ylca r b on yl)oxy]-2-t r iflu or om et h yl-
1,4,5,6-tetr a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te Hy-
d r och lor id e [(S)-12k ]. To a solution of (S)-10k (5.6 mg, 8
µmol) and p-nitrophenyl chloroformate (2.0 mg, 10 µmol) in
CH2Cl2 was added Et3N (1.4 µL, 10 µmol) at 0 °C, and the
mixture was stirred for 50 min. After addition of 4-methylpip-
erazine (1.4 µL, 12 µmol), the mixture was further stirred
overnight. After dilution with CHCl3, the resulting mixture
was washed with 10% NaHCO3 solution, water, and brine. The
organic layer was dried over anhydrous Na2SO4, filtered, and
then concentrated in vacuo. Flash chromatography (CHCl3:
MeOH:acetone ) 40:3:1) of the residue gave the free base of
(S)-12k . Treatments of this free base with saturated HCl-
1H). MS (FAB) m/z: 692 (MH+). HRMS (FAB) for C34H26
-
ClF3N5O6 (MH+): calcd, 692.1524; found, 692.1541.
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(6-m et h -
oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10s]. This compound (S)-10s (13.6
mg, 78%) was prepared from (S)-14 (11.2 mg, 25 µmol) and
16s (9.0 mg, 25 µmol). [R]D25 ) +60° (c ) 0.20, THF). 1H NMR
(DMSO-d6): δ 3.53 (dd, J ) 10.8 Hz, 8.8 Hz, 1H), 3.84-3.94
(m, 1H), 3.89, 3.97 (sx2, each 3H), 4.25-4.35 (m, 1H), 4.54 (d,
J ) 10.8 Hz, 1H), 4.73 (t, J ) 10.8 Hz, 1H), 7.18 (s, 1H), 7.45
(dd, J ) 8.8 Hz, 2.9 Hz, 1H), 7.49 (d, J ) 8.8 Hz, 1H), 7.67 (d,
J ) 2.0 Hz, 1H), 7.73 (d, J ) 7.8 Hz, 1H), 7.95 (brs, 1H), 8.20
(d, J ) 8.8 Hz, 1H), 8.38 (s, 1H), 8.61 (s, 1H), 9.32 (s, 1H),
10.59 (s, 1H), 10.66 (s, 1H), 11.72 (s, 1H), 13.11 (s, 1H). MS
(FAB) m/z: 692 (MH+). HRMS (FAB) for C34H26ClF3N5O6
(MH+): calcd, 692.1524; found, 692.1510.
24
MeOH (0.1 mL) gave (S)-12k [1.9 mg, 27% from (S)-10k ]. [R]D
) +12° (c ) 0.19, MeOH). H NMR (DMSO-d6): δ 2.85 (brs,
1
3H), 3.11-3.70 (m, 7H), 3.80-3.90 (m, 1H), 3.83, 3.92 (sx2,
each 3H), 4.10-4.23 (m, 1H), 4.42 (brs, 2H), 4.59 (d, J ) 10.8
Hz, 1H), 4.81 (t, J ) 10.8 Hz, 1H), 7.09 (dd, J ) 8.8 Hz, 2.0
Hz, 1H), 7.22 (s, 1H), 7.32 (d, J ) 2.0 Hz, 1H), 7.50 (d, J ) 8.8
Hz, 1H), 7.55-7.65 (m, 2H), 7.70 (s, 1H), 8.20 (s, 1H), 8.22 (s,
1H), 10.46 (s, 1H), 10.85 (brs, 1H), 11.66 (s, 1H), 13.17 (brs,
(S)-Met h yl 4-Ch lor om et h yl-8-h yd r oxy-6-[5-[(7-m et h -
oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bo-
n yl]-2-t r iflu or om et h yl-1,4,5,6-t et r a h yd r op yr r olo[3,2-e]-
in d ole-3-ca r boxyla te [(S)-10t]. This compound (S)-10t (9.4
mg, 68%) was prepared from (S)-14 (9.0 mg, 20 µmol) and 16t

AT-3510: Novel CPI Derivative
J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8 1455
d r och lor id e [(S)-12v]. This compound (S)-12v (12.4 mg, 50%)
1H). MS (FAB) m/z: 807 (free base) (MH+). HRMS (FAB) for
39H35ClF3N6O8 (free base) (MH+): calcd, 807.2157; found,
was prepared from (S)-10v (20.4 mg, 27 µmol). [R]D ) +38°
26
C
807.2125.
(c ) 0.40, MeOH). 1H NMR (CDCl3 + DMSO-d6): δ 2.30 (s,
3H), 2.47 (s, 4H), 3.39 (t, J ) 9.3 Hz, 1H), 3.63 (s, 2H), 3.78 (s,
2H), 3.84 (dd, J ) 11.2 Hz, 3.4 Hz, 1H), 3.96, 4.04, 4.05, 4.12
(sx4, each 3H), 4.52-4.59 (m, 2H), 4.74 (d, J ) 9.8 Hz, 1H),
7.01 (s, 1H), 7.12 (s, 1H), 7.38 (d, J ) 8.8 Hz, 1H), 7.47 (d, J
) 8.8 Hz, 1H), 8.32 (s, 1H), 8.38 (s, 1H), 8.90 (s, 1H), 9.02 (s,
1H), 9.57 (br, 1H), 10.20 (s, 1H). MS (FAB) m/z: 878 (free base)
(MH+). HRMS (FAB) for C42H40ClF3N7O9 (free base) (MH+):
calcd, 878.2528; found, 878.2532.
Other prodrugs of the seco-Cl-MCTFCPI derivatives (S)-
12l-n ,q,v were prepared in the same manner as described
above.
(S)-Meth yl 4-Ch lor om eth yl-6-[5-[(6-m eth oxyben zofu r an -
2-y lc a r b o n y l)a m i n o ]-1H -i n d o l-2-y lc a r b o n y l]-8-[(4-
m et h ylp ip er a zin -1-ylca r b on yl)oxy]-2-t r iflu or om et h yl-
1,4,5,6-tetr a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te Hy-
d r och lor id e [(S)-12l]. This compound (S)-12l (3.7 mg, 46%)
was prepared from (S)-10l (6.5 mg, 10 µmol). [R]D24 ) +5.8° (c
5,6,7-Tr im eth oxyben zofu r a n -2-ca r boxylic Acid (16d ).
A solution of 17 (100 mg, 0.54 mmol) and hexamethylenetet-
ramine (75.7 mg, 0.54 mmol) in TFA (0.5 mL) was heated at
reflux for 4 h. After the reaction was quenched with addition
of ice, the resulting mixture was further stirred for 15 min
and extracted with ether. The combined organic extracts were
washed with saturated NaHCO3 solution and brine, dried over
anhydrous Na2SO4, filtered, and then concentrated in vacuo.
Flash chromatography (benzene:acetone ) 10:1) of the residue
gave 18 as a powder (79.4 mg, 69%). Mp: 41-43 °C (recrystal-
1
) 0.13, MeOH). H NMR (DMSO-d6): δ 2.86 (brs, 3H), 3.10-
3.70 (m, 7H), 3.88-3.97 (m, 1H), 3.87, 3.92 (sx2, each 3H), 4.16
(m, 1H), 4.42 (m, 2H), 4.60 (d, J ) 10.8 Hz, 1H), 4.81 (t, J )
9.7 Hz, 1H), 7.00 (dd, J ) 8.8 Hz, 2.0 Hz, 1H), 7.22 (s, 1H),
7.27 (s, 1H), 7.50 (d, J ) 8.8 Hz, 1H), 7.61 (d, J ) 8.8 Hz, 1H),
7.66-7.76 (m, 2H), 8.20 (s, 1H), 8.21 (s, 1H), 10.35 (s, 1H),
10.55 (brs, 1H), 11.64 (s, 1H), 13.15 (brs, 1H). MS (FAB) m/z:
807 (free base) (MH+). HRMS (FAB) for C39H35ClF3N6O8 (free
base) (MH+): calcd, 807.2157; found, 807.2155.
1
lized from hexane) (lit.13 mp 39-40 °C). H NMR (CDCl3): δ
(S)-Meth yl 4-Ch lor om eth yl-6-[5-[(7-m eth oxyben zofu r an -
2-y lc a r b o n y l)a m i n o ]-1H -i n d o l-2-y lc a r b o n y l]-8-[(4-
m et h ylp ip er a zin -1-ylca r b on yl)oxy]-2-t r iflu or om et h yl-
1,4,5,6-tetr a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te Hy-
d r och lor id e [(S)-12m ]. This compound (S)-12m (17.5 mg,
61%) was prepared from (S)-10m (23.0 mg, 34 µmol). Mp:
3.86 (s, 3H), 3.93 (s, 3H), 4.05 (s, 3H), 6.72 (s, 1H), 9.76 (s,
1H), 10.97 (brs, 1H).
A suspension of 18 (531 mg, 2.5 mmol), ethyl bromoacetate
(0.30 mL, 2.8 mmol), and K2CO3 (691 mg, 5.0 mmol) in DMF
(5 mL) was heated at 80 °C for 20 h. After cooling, filtration
and concentration in vacuo gave a residue, which was diluted
with CH2Cl2 and washed with water and brine. The organic
layer was dried over anhydrous Na2SO4, filtered, and then
concentrated in vacuo. Flash chromatography (benzene:AcOEt
) 20:1) of the residue gave 19 as colorless needles (435 mg,
62%). Mp: 55-57 °C. 1H NMR (CDCl3): δ 1.42 (t, J ) 7.1 Hz,
3H), 3.90 (s, 3H), 3.93 (s, 3H), 4.24 (s, 3H), 4.42 (q, J ) 7.2
Hz, 2H), 6.78 (s, 1H), 7.43 (s, 1H). IR (KBr): 1720 cm-1. MS
(EI) m/z: 280 (M+). Anal. (C14H16O6) C, H, N.
A mixture of 19 (100 mg, 0.36 mmol) and 20% KOH (0.3
mL) in EtOH (1.5 mL) was stirred at 0 °C for 2.5 h. After the
reaction was quenched with addition of 10% citric acid solution,
the resulting precipitates were collected by filtration, washed
with hexane, and then dried in vacuo to give 16d as a colorless
powder (71.6 mg, 79%). Mp: 185-187 °C. 1H NMR (DMSO-
d6): δ 3.78 (s, 3H), 3.83 (s, 3H), 4.07 (s, 3H), 7.03 (s, 1H), 7.56
(s, 1H), 13.50 (brs, 1H). IR (KBr): 1686 cm-1. MS (EI) m/z:
252 (M+). Anal. (C12H12O6) C, H, N.
5-(Ben zofu r a n -2-yl)-1H-in d ole-2-ca r boxylic Acid (16e).
A solution of 22 (254 mg, 1.0 mmol), benzofuran-2-boric acid
(194 mg, 1.2 mmol, commercially available), Pd(PPh3)4 (57.8
mg, 0.05 mmol), and Et3N (1.4 mL, 10 mmol) was heated at
100 °C for 2.5 h. After dilution with water, the mixture was
extracted with CH2Cl2. The combined organic extracts were
dried over anhydrous Na2SO4, filtered, and then concentrated
in vacuo. Flash chromatography (CH2Cl2) of the residue gave
23 as pale yellow crystals (128 mg, 44%). Mp: 220.5-221.5
°C. 1H NMR (DMSO-d6): δ 3.95 (s, 3H), 7.00 (s, 1H), 7.20-
7.27 (m, 3H), 7.51 (d, J ) 7.8 Hz, 1H), 7.57 (d, J ) 8.3 Hz,
2H), 7.77 (dd, J ) 8.8 Hz, 1.5 Hz, 1H), 8.20 (s, 1H).
24
225-240 °C dec. [R]D ) +26° (c ) 0.4, MeOH). 1H NMR
(DMSO-d6): δ 2.86 (s, 3H), 3.20-3.69 (m, 6H), 3.62 (t, J )
10.3 Hz, 1H), 3.94 (m, 1H), 3.92, 4.01 (sx2, each 3H), 4.19 (m,
1H), 4.43 (m, 2H), 4.63 (d, J ) 10.3 Hz, 1H), 4.78 (t, J ) 9.3
Hz, 1H), 7.07 (d, J ) 7.3 Hz, 1H), 7.19 (d, J ) 2.0 Hz, 1H),
7.26 (t, J ) 7.8 Hz, 1H), 7.34 (d, J ) 7.3 Hz, 1H), 7.51 (d, J )
8.8 Hz, 1H), 7.62 (dd, J ) 8.8 Hz, 1.5 Hz, 1H), 7.75 (s, 1H),
8.20 (s, 1H), 8.23 (d, J ) 1.5 Hz, 1H), 10.40 (s, 1H), 11.21 (brs,
1H), 11.63 (s, 1H), 13.11 (s, 1H). IR (KBr): 3411, 1720 cm-1
.
MS (FAB) m/z: 807 (MH+). HRMS (FAB) for C39H35ClF3N6O8
(free base) (MH+): calcd, 807.2157; found, 807.2191. Anal.
(C39H34ClF3N6O8‚HCl‚9/2H2O) C, H, N.
(S)-Meth yl 4-Ch lor om eth yl-8-[(4-m eth ylp ip er a zin -1-yl-
ca r bon yl)oxy]-2-tr iflu or om eth yl-6-[5-[(5,6,7-tr im eth oxy-
ben zofu r a n -2-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bon yl]-
1,4,5,6-tetr a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te Hy-
d r och lor id e [(S)-12n ]. This compound (S)-12n (1.0 mg, 14%)
25
was prepared from (S)-10n (5.7 mg, 8 µmol). [R]D ) +22° (c
1
) 0.13, MeOH). H NMR (DMSO-d6): δ 2.86 (brs, 3H), 3.10-
3.70 (m, 7H), 3.89-3.98 (m, 1H), 3.81, 3.86, 3.91, 4.17 (sx4,
each 3H), 4.01-4.24 (m, 1H), 4.42 (m, 2H), 4.60 (d, J ) 10.8
Hz, 1H), 4.81 (t, J ) 10.8 Hz, 1H), 7.08 (s, 1H), 7.22 (d, J )
2.0 Hz, 1H), 7.51 (d, J ) 8.8 Hz, 1H), 7.57 (dd, J ) 8.8 Hz, 2.0
Hz, 1H), 7.69 (s, 1H), 8.18 (brs, 1H), 8.20 (s, 1H), 10.33 (s, 1H),
10.70 (brs, 1H), 11.67 (s, 1H), 13.16 (brs, 1H). MS (FAB) m/z:
867 (free base) (MH+). HRMS (FAB) for C41H39ClF3N6O10 (free
base) (MH+): calcd, 867.2368; found, 867.2365.
(S)-Meth yl 4-Ch lor om eth yl-6-[5-[(isoqu in olin -3-ylca r -
bon yl)a m in o]-1H-in d ol-2-ylca r bon yl]-8-[(4-m eth ylp ip er -
a zin -1-ylca r bon yl)oxy]-2-tr iflu or om eth yl-1,4,5,6-tetr a h y-
dr opyr r olo[3,2-e]in dole-3-car boxylate Hydr och lor ide [(S)-
12q]. This compound (S)-12q (37.8 mg, 66%) was prepared
from (S)-10q (40.2 mg, 70 µmol). [R]D25 ) +40° (c ) 0.20, DMF).
1H NMR (DMSO-d6): δ 2.88 (s, 3H), 3.20-3.65 (m, 7H), 3.85-
4.00 (m, 1H), 3.92 (s, 3H), 4.15-4.25 (m, 1H), 4.43 (m, 2H),
4.61 (d, J ) 11.2 Hz, 1H), 4.82 (t, J ) 10.3 Hz, 1H), 7.23 (s,
1H), 7.52 (d, J ) 8.8 Hz, 1H), 7.76 (d, J ) 8.8 Hz, 1H), 7.86
(dd, J ) 6.8 Hz, 1.0 Hz, 1H), 7.92 (dd, J ) 6.8 Hz, 1.0 Hz, 1H),
8.21 (s, 2H), 8.27 (d, J ) 8.3 Hz, 1H), 8.32 (d, J ) 7.8 Hz, 1H),
8.41 (s, 1H), 8.73 (s, 1H), 9.49 (s, 1H), 10.45 (br, 1H), 10.71 (s,
1H), 11.65 (brs, 1H), 13.14 (s, 1H). MS (FAB) m/z: 788 (free
base) (MH+). HRMS (FAB) for C39H34ClF3N7O6 (free base)
(MH+): calcd, 788.2211; found, 788.2185.
A mixture of 23 (84.2 mg, 0.29 mmol) and 20% KOH (0.7
mL) in MeOH (0.7 mL) and DMSO (0.7 mL) was stirred at 50
°C for 1 h. After the reaction was quenched by the addition of
10% citric acid solution, the resulting precipitates were col-
lected by filtration, washed with water, and then dried in vacuo
to give 16e as a pale yellow powder (78.2 mg, 98%). Mp: 280
1
°C dec. H NMR (DMSO-d6): δ 7.20-7.31 (m, 4H), 7.54 (d, J
) 8.8 Hz, 1H), 7.60-7.64 (m, 2H), 7.83 (d, J ) 8.8 Hz, 1H),
8.21 (s, 1H), 11.98 (s, 1H), 13.11 (br, 1H). IR (KBr): 3439, 1672
cm-1. MS (EI) m/z: 277 (M+). Anal. (C17H11NO3 1/10H2O) C,
H, N.
5-[(5,6,7-Tr im et h oxy-1H -in d ol-2-ylca r b on yl)a m in o]-
1H-in d ole-2-ca r boxylic Acid (16g). To a solution of ethyl
5-aminoindole-2-carboxylate4c (102 mg, 0.50 mmol) and 16b9
(126 mg, 0.50 mmol) was added EDCI (288 mg, 1.5 mmol) at
room temperature, and the mixture was stirred for overnight.
After dilution with water, the resulting precipitates were
(S)-Meth yl 4-Ch lor om eth yl-8-[(4-m eth ylp ip er a zin -1-yl-
ca r bon yl)oxy]-2-tr iflu or om eth yl-6-[5-[(5,6,7-tr im eth oxy-
isoqu in olin -3-ylca r bon yl)a m in o]-1H-in d ol-2-ylca r bon yl]-
1,4,5,6-tetr a h yd r op yr r olo[3,2-e]in d ole-3-ca r boxyla te Hy-

1456 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8
Fukuda et al.
collected by filtration, washed with water and MeOH, and then
dried in vacuo to give the ethyl ester of 16g as pale yellow
crystals (162 mg, 74%). Mp: 272-273 °C. 1H NMR (DMSO-
d6): δ 1.36 (t, J ) 6.8 Hz, 3H), 3.80, 3.82, 3.97 (sx3, each 3H),
4.35 (q, J ) 6.8 Hz, 2H), 6.94 (s, 1H), 7.15 (s, 1H), 7.23 (s,
1H), 7.45 (d, J ) 8.8 Hz, 1H), 7.57 (dd, J ) 8.8 Hz, 2.0 Hz,
1H), 8.15 (s, 1H), 10.03 (s, 1H), 11.42 (s, 1H), 11.86 (s, 1H).
Anal. (C23H23N3O6) C, H, N.
A mixture of the ethyl ester of 16g (131.2 mg, 0.30 mmol)
and 20% KOH (1 mL) in EtOH (1 mL) was stirred at 60 °C for
1 h. After the reaction was quenched by the addition of
concentrated HCl, the resulting precipitates were collected by
filtration, washed with water, and then dried in vacuo to give
16g as a pale yellow powder (109 mg, 89%). Mp: 237-238 °C.
1H NMR (DMSO-d6): δ 3.79, 3.82, 3.96 (sx3, each 3H), 6.95
(s, 1H), 7.08 (d, J ) 1.5 Hz, 1H), 7.23 (d, J ) 2.0 Hz, 1H), 7.42
(d, J ) 9.3 Hz, 1H), 7.54 (dd, J ) 9.3 Hz, 2.0 Hz, 1H), 8.12 (s,
1H), 10.02 (s, 1H), 11.44 (s, 1H), 11.74 (s, 1H), 12.96 (br, 1H).
IR (KBr): 3416, 1699, 1647 cm-1. MS (FAB) m/z: 410 (MH+).
Anal. (C21H19N3O6) C, H, N.
(4.08 g, 20 mmol) and 7-methoxybenzofuran-2-carboxylic acid
(3.84 g, 20 mmol). Ethyl ester of 16m : mp 196.5-197.5 °C.
1H NMR (DMSO-d6): δ 1.35 (t, J ) 6.8 Hz, 1H), 4.00 (s, 3H),
4.35 (q, J ) 14.2 Hz, 6.8 Hz, 2H), 7.10 (d, J ) 7.8 Hz, 1H),
7.17 (s, 1H), 7.28 (t, J ) 7.8 Hz, 1H), 7.36 (d, J ) 7.8 Hz, 1H),
7.45 (d, J ) 9.3 Hz, 1H), 7.61 (m, 1H), 7.74 (d, J ) 1.0 Hz,
1H), 8.15 (dd, J ) 4.4 Hz, 2.0 Hz, 1H), 10.40 (s, 1H), 11.89 (s,
1H). IR (KBr): 3321, 1697 cm-1. MS (EI) m/z: 378 (M+). Anal.
(C21H18N2O5‚1/2H2O) C, H, N.
16m : mp >300 °C. 1H NMR (DMSO-d6): δ 3.99 (s, 3H),
7.09-7.11 (m, 2H), 7.28 (t, J ) 7.8 Hz, 1H), 7.36 (d, J ) 8.3
Hz, 1H), 7.42 (d, J ) 8.8 Hz, 1H), 7.58 (dd, J ) 8.8 Hz, 2.0 Hz,
1H), 7.74 (s, 1H), 8.14 (s, 1H), 10.38 (s, 1H), 11.76 (s, 1H), 12.97
(br, 1H). IR (KBr): 3260, 1670 cm-1. MS (EI) m/z: 350 (M+).
Anal. (C19H14N2O5‚1/4H2O) C, H, N.
5-[(5,6,7-Tr im eth oxyben zofu r a n -2-ylca r bon yl)a m in o]-
1H-in d ole-2-ca r boxylic Acid (16n ). The ethyl ester of 16n
(26.8 mg, 61%) was prepared from ethyl 5-aminoindole-2-
carboxylate (20.4 mg, 0.10 mmol) and 16d (25.2 mg, 0.10
mmol). Hydrolysis of the ethyl ester of 16n (25.0 mg, 57 mmol)
gave 16n (17.5 mg, 75%). Mp: 259-261 °C. 1H NMR (DMSO-
d6): δ 3.80 (s, 3H), 3.85 (s, 3H), 4.16 (s, 3H), 7.08 (s, 1H), 7.09
(s, 1H), 7.42 (d, J ) 9.8 Hz, 1H), 7.52-7.59 (m, 1H), 7.69 (s,
1H), 8.09 (s, 1H), 10.28 (s, 1H), 11.76 (brs, 1H), 13.00 (brs,
1H). IR (KBr): 3275, 1676 cm-1. MS (EI) m/z: 410 (M+). Anal.
(C21H18N2O7‚5/4H2O) C, H, N.
5-[(Na p h th a len -2-ylca r bon yl)a m in o]-1H-in d ole-2-ca r -
boxylic Acid (16o). To a solution of ethyl 5-aminoindole-2-
carboxylate (30.6 mg, 0.15 mmol) and Et3N (21 µL, 0.15 mmol)
in THF (1 mL) was added a solution of 2-naphthoyl chloride
(28.6 mg, 0.15 mmol) in THF (1 mL) at 0 °C, and the mixture
was stirred for 1 h. After concentration of the reaction mixture
in vacuo, the crude ethyl ester was hydrolyzed in the same
manner as described for the preparation of 16g, giving 16o
(48.0 mg, 97%). Mp: >300 °C. 1H NMR (DMSO-d6): δ 6.72 (s,
1H), 7.34 (d, J ) 8.3 Hz, 1H), 7.46 (m, 1H), 7.60-7.66 (m, 2H),
8.00-8.10 (m, 5H), 8.60 (s, 1H), 10.27 (s, 1H), 11.15 (br, 1H).
IR (KBr): 3256, 1639 cm-1. MS (FAB) m/z: 331 (MH+). HRMS
(FAB) for C20H15N2O3 (MH+): calcd, 331.1083; found, 331.1064.
5-[(Qu in olin -3-ylca r bon yl)a m in o]-1H-in d ole-2-ca r box-
ylic Acid (16p ). The ethyl ester of 16p (153 mg, 85%) was
prepared from ethyl 5-aminoindole-2-carboxylate (102 mg, 0.50
mmol) and quinoline-3-carboxylic acid (86.6 mg, 0.50 mmol,
commercially available). Hydrolysis of the ethyl ester of 16p
(108 mg, 0.30 mmol) gave 16p (71.7 mg, 72%). Mp: >300 °C.
1H NMR (DMSO-d6): δ 7.12 (s, 1H), 7.45 (d, J ) 8.8 Hz, 1H),
7.60 (dd, J ) 9.3 Hz, 2.0 Hz, 1H), 7.73 (t, J ) 6.8 Hz, 1H),
7.90 (t, J ) 6.8 Hz, 1H), 8.12-8.20 (m, 3H), 8.98 (d, J ) 2.0
Hz, 1H), 9.32 (d, J ) 2.0 Hz, 1H), 9.39 (d, J ) 2.4 Hz, 1H),
10.55 (s, 1H), 11.79 (s, 1H), 12.76 (br, 1H). IR (KBr): 3287,
1647 cm-1. MS (FAB) m/z: 332 (MH+). Anal. (C19H13N3O3‚1/
2H2O) C, H, N.
Other carboxylic acids 16h ,j-w were prepared in the same
manner as described above.
5-[(4,5,6-Tr im et h oxy-1H -in d ol-2-ylca r b on yl)a m in o]-
1H-in d ole-2-ca r boxylic Acid (16h ). The ethyl ester of 16h
(151 mg, 69%) was prepared from ethyl 5-aminoindole-2-
carboxylate (102 mg, 0.50 mmol) and 16c (126 mg, 0.50 mmol).
Hydrolysis of the ethyl ester of 16h (87.5 mg, 0.20 mmol) gave
1
16h (75.4 mg, 63%). Mp: 284-285 °C dec. H NMR (DMSO-
d6): δ 3.71, 3.81, 4.05 (sx3, each 3H), 6.71 (s, 1H), 7.08 (s, 1H),
7.41 (d, J ) 8.8 Hz, 1H), 7.50 (s, 1H), 7.57 (dd, J ) 9.3 Hz, 2.0
Hz, 1H), 8.13 (d, J ) 2.0 Hz, 1H), 9.99 (s, 1H), 11.51 (d, J )
2.0 Hz, 1H), 11.73 (s, 1H), 12.91 (brs, 1H). IR (KBr): 3298,
1685, 1630 cm-1. MS (EI) m/z: 409 (M+). Anal. (C21H19N3O6‚
9/5H2O) C, H, N.
5-[(4-Meth oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16j). The ethyl ester of 16j (48.5 mg,
53%) was prepared from ethyl 5-aminoindole-2-carboxylate
(49.0 mg, 0.24 mmol) and 4-methoxybenzofuran-2-carboxylic
acid (46.1 mg, 0.24 mmol). Hydrolysis of the ethyl ester of 16j
(45.4 mg, 0.12 mmol) gave 16j (20.4 mg, 49%). Mp: 255-257
1
°C. H NMR (DMSO-d6): δ 3.96 (s, 3H), 6.89 (d, J ) 7.8 Hz,
1H), 7.07 (s, 1H), 7.31 (d, J ) 8.8 Hz, 1H), 7.41 (d, J ) 7.8 Hz,
1H), 7.44 (t, J ) 7.8 Hz, 1H), 7.56 (dd, J ) 8.8 Hz, 2.0 Hz,
1H), 7.78 (s, 1H), 8.14 (s, 1H), 10.35 (s, 1H), 11.72 (brs, 1H),
13.00 (brs, 1H). IR (KBr): 3293, 1688 cm-1. MS (EI) m/z: 350
(M+). HRMS (EI) for C19H14N2O5 (M+): calcd, 350.0903; found,
350.0945.
5-[(5-Meth oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16k ). The ethyl ester of 16k (108
mg, 58%) was prepared from ethyl 5-aminoindole-2-carboxylate
(100 mg, 0.49 mmol) and 5-methoxybenzofuran-2-carboxylic
acid (94.2 mg, 0.49 mmol). Hydrolysis of the ethyl ester of 16k
(100 mg, 0.26 mmol) gave 16k (61.1 mg, 67%). Mp: 232-235
5-[(Isoqu in olin -3-ylca r bon yl)a m in o]-1H-in d ole-2-ca r -
boxylic Acid (16q). This compound 16q (62.7 mg, 38%), mp
>300 °C, was prepared from ethyl 5-aminoindole-2-carboxylate
(102 mg, 0.50 mmol) and isoquinoline-3-carboxylic acid (86.6
mg, 0.50 mmol, commercially available). 1H NMR (DMSO-
d6): δ 7.09 (d, J ) 1.5 Hz, 1H), 7.43 (d, J ) 8.8 Hz, 1H), 7.71
(dd, J ) 8.8 Hz, 2.0 Hz, 1H), 7.85 (t, J ) 6.8 Hz, 1H), 7.92 (t,
J ) 6.8 Hz, 1H), 8.26-8.33 (m, 3H), 8.71 (s, 1H), 9.48 (s, 1H),
1
°C. H NMR (DMSO-d6): δ 3.85 (s, 3H), 7.08 (dd, J ) 8.8 Hz,
2.9 Hz, 1H), 7.09 (s, 1H), 7.31 (d, J ) 2.9 Hz, 1H), 7.42 (d, J
) 8.8 Hz, 1H), 7.58 (dd, J ) 8.8 Hz, 2.0 Hz, 1H), 7.62 (d, J )
8.8 Hz, 1H), 7.68 (s, 1H), 8.13 (s, 1H), 10.41 (brs, 1H), 11.27
(brs, 1H), 11.77 (brs, 1H). IR (KBr): 3238, 1672 cm-1. MS (EI)
m/z: 350 (M+). Anal. (C19H14N2O5‚H2O) C, H, N.
5-[(6-Meth oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16l). The ethyl ester of 16l (44.0 mg,
24%) was prepared from ethyl 5-aminoindole-2-carboxylate
(100 mg, 0.49 mmol) and 6-methoxybenzofuran-2-carboxylic
acid (94.2 mg, 0.49 mmol). Hydrolysis of the ethyl ester of 16l
(45.4 mg, 0.12 mmol) gave 16l (30.0 mg, 78%). Mp: 278-281
10.67 (s, 1H), 11.75 (s, 1H). IR (KBr): 3298, 1667, 1535 cm-1
.
MS (FAB) m/z: 332 (MH+). Anal. (C19H13N3O3‚1/2H2O) C, H,
N.
5-[(5-Meth oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16r ). The ethyl ester of 16r (25.1
mg, 54%) was prepared from ethyl 5-aminoindole-2-carboxylate
(24.5 mg, 0.12 mmol) and 35a (25.0 mg, 0.12 mmol). Hydrolysis
of the ethyl ester of 16r (23.0 mg, 60 µmol) gave 16r (18.6 mg,
1
°C. H NMR (DMSO-d6): δ 3.86 (s, 3H), 7.00 (dd, J ) 8.8 Hz,
2.0 Hz, 1H), 7.01 (s, 1H), 7.28 (s, 1H), 7.41 (d, J ) 8.8 Hz,
1H), 7.56 (d, J ) 8.8 Hz, 1H), 7.66-7.74 (m, 2H), 8.13 (s, 1H),
10.30 (s, 1H), 11.74 (s, 1H), 12.60-13.40 (br, 1H). IR (KBr):
3281, 1671 cm-1. MS (EI) m/z: 350 (M+). Anal. (C19H14N2O5‚
1/2H2O) C, H, N.
1
86%). Mp: 265-267 °C. H NMR (DMSO-d6): δ 4.08 (s, 3H),
6.93 (brs, 1H), 7.34-7.42 (m, 1H), 7.37 (d, J ) 7.8 Hz, 1H),
7.58-7.66 (m, 1H), 7.77 (t, J ) 7.8 Hz, 1H), 7.85 (d, J ) 7.8
Hz, 1H), 8.25 (brs, 1H), 8.80 (s, 1H), 9.43 (s, 1H), 10.60 (brs,
1H), 11.49 (brs, 1H). IR (KBr): 3312, 1684, 1652 cm-1. MS
(FAB) m/z: 362 (MH+). Anal. (C20H15N3O4‚6/5H2O) C, H, N.
5-[(7-Meth oxyben zofu r a n -2-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16m ). This compound 16m (5.84 g,
83%) was prepared from ethyl 5-aminoindole-2-carboxylate

AT-3510: Novel CPI Derivative
J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8 1457
5-[(6-Meth oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16s). The ethyl ester of 16s (82.9
mg, 61%) was prepared from ethyl 5-aminoindole-2-carboxylate
(71.5 mg, 0.35 mmol) and 27a (71.1 mg, 0.35 mmol). Hydrolysis
of the ethyl ester of 16s (80.0 mg, 0.21 mmol) gave 16s (61.5
(d, J ) 2.0 Hz, 1H), 7.37 (dd, J ) 8.8 Hz, 2.0 Hz, 1H), 7.95 (d,
J ) 8.8 Hz, 1H), 8.51 (s, 1H), 9.19 (s, 1H). 26b: 1H NMR
(CDCl3): δ 4.06 (s, 3Hx2), 7.03 (d, J ) 7.8 Hz, 1H), 7.51 (d, J
) 7.8 Hz, 1H), 7.69 (t, J ) 7.8 Hz, 1H), 8.53 (s, 1H), 9.69 (s,
1H).
Hydrolysis of 26a ,b in a manner similar to that described
for the preparation of 16d from 19 gave 27a (79.0 mg, 79%)
and 27b (4.7 mg, 76%), respectively. 27a : mp 178-180 °C.
1H NMR (CDCl3): δ 4.00 (s, 3H), 7.25-7.26 (m, 1H), 7.41 (dd,
J ) 8.8 Hz, 2.0 Hz, 1H), 7.99 (d, J ) 8.8 Hz, 1H), 8.56 (s, 1H),
9.07 (s, 1H). IR (KBr): 3411, 1649 cm-1. MS (EI) m/z: 203
(M+). Anal. (C11H9NO3‚5/4H2O) C, H, N. As for 27b, it was
directly subjected to the next reaction without collecting
analytical data.
1
mg, 81%). Mp: 267-269 °C. H NMR (DMSO-d6): δ 3.97 (s,
3H), 7.09 (s, 3H), 7.43 (d, J ) 8.8 Hz, 1H), 7.45 (dd, J ) 8.8
Hz, 2.9 Hz, 1H), 7.67 (d, J ) 2.9 Hz, 1H), 7.69 (dd, J ) 8.8 Hz,
2.0 Hz, 1H), 8.20 (d, J ) 8.8 Hz, 1H), 8.33 (s, 1H), 8.59 (s,
1H), 9.31 (s, 1H), 10.63 (s, 1H), 11.74 (s, 1H). IR (KBr): 3292,
1698, 1624 cm-1. MS (FAB) m/z: 362 (MH+). Anal. (C20H15N3O4‚
1/4H2O) C, H, N.
5-[(7-Meth oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16t). The ethyl ester of 16t (29.5
mg, 58%) was prepared from ethyl 5-aminoindole-2-carboxylate
(25.5 mg, 0.13 mmol) and 31 (25.5 mg, 0.13 mmol). Hydrolysis
of the ethyl ester of 16t (28.5 mg, 70 µmol) gave 16t (19.4 mg,
7-Meth oxyisoqu in olin e-3-ca r boxylic Acid (31). To a
solution of 28 (500 mg, 2.1 mmol) was added oxalyl chloride
(0.20 mL, 2.3 mmol) at room temperature, and the mixture
was stirred for 30 min. To the mixture was added FeCl3 (409
mg, 2.5 mmol) at -10 °C, and the resulting mixture was stirred
at room temperature for 5 h. After the reaction was quenched
by the addition of 1 N HCl, the resulting solution was extracted
with CH2Cl2. The combined organic extracts were washed with
brine, dried over anhydrous Na2SO4, filtered, and then con-
centrated in vacuo. The residue was dissolved in MeOH-H2-
SO4 (19:1) (12 mL), and the solution was heated at reflux for
4 h. After the reaction was quenched by the addition of 10%
NaHCO3 solution, the mixture was extracted with CHCl3. The
combined organic extracts were washed with brine, dried over
anhydrous Na2SO4, and filtered, and then concentrated in
vacuo. Flash chromatography (CH2Cl2) of the residue gave 29
(64.9 mg). This material was directly subjected to the next
reaction without collecting analytical data. A suspension of
29 (64.9 mg) and 10% Pd-C (52 mg) in xylene (5 mL) was
heated at 100 °C for 3.5 h. The reaction mixture was concen-
trated in vacuo after filtration, and the residue was purified
by preparative TLC (CH2Cl2:AcOEt ) 7:3) to give 30 as a pale
1
73%). Mp: 290-293 °C. H NMR (DMSO-d6): δ 3.98 (s, 3H),
6.95 (brs, 1H), 7.40 (d, J ) 8.8 Hz, 1H), 7.54 (dd, J ) 8.8 Hz,
2.4 Hz, 1H), 7.64 (dd, J ) 8.8 Hz, 2.2 Hz, 1H), 7.71 (d, J ) 2.0
Hz, 1H), 8.18 (d, J ) 8.8 Hz, 1H), 8.27 (brs, 1H), 8.63 (s, 1H),
9.35 (s, 1H), 10.55 (s, 1H), 11.52 (s, 1H). IR (KBr): 3335, 1679,
1620 cm-1. MS (FAB) m/z: 362 (MH+). Anal. (C20H15N3O4‚1/
4H2O) C, H, N.
5-[(8-Meth oxyisoqu in olin -3-ylca r bon yl)a m in o]-1H-in -
d ole-2-ca r boxylic Acid (16u ). This compound 16u (4.4 mg,
52%) was prepared from ethyl 5-aminoindole-2-carboxylate (4.7
mg, 23 µmol) and 27b (4.7 mg, 23 µmol). 1H NMR (DMSO-d6):
δ ) 4.08 (s, 3H), 6.59 (s, 1H), 7.28 (d, J ) 7.8 Hz, 1H), 7.39 (d,
J ) 8.8 Hz, 1H), 7.65 (brs, 1H), 7.77-7.86 (m, 2H), 8.26 (s,
1H), 8.63 (s, 1H), 9.58 (s, 1H), 10.64 (brs, 1H), 11.64 (brs, 1H).
Without collecting further analytical data, 16u was directly
subjected to the next reaction.
5-[(5,6,7-Tr im eth oxyisoqu in olin -3-ylca r bon yl)a m in o]-
1H-in d ole-2-ca r boxylic Acid (16v). This compound 16v
(16.8 mg, 50%) was prepared from ethyl 5-aminoindole-2-
carboxylate (16.3 mg, 80 µmol) and 35b (21 mg, 80 µmol). MS
(FAB) m/z: 422 (MH+). HRMS (FAB) for C22H20N3O6 (MH+):
calcd, 422.1352; found, 422.1380. Without collecting further
analytical data, 16v was directly subjected to the next reaction.
5-[(5,6,7-Tr im eth oxycin n olin -3-ylca r bon yl)a m in o]-1H-
in d ole-2-ca r boxylic Acid (16w ). This compound 16w (29.5
mg, 47%), mp 260 °C dec, was prepared from ethyl 5-aminoin-
dole-2-carboxylate (30.6 mg, 0.15 mmol) and 41 (39.6 mg, 0.15
mmol). 1H NMR (DMSO-d6): δ 4.01, 4.10, 4.12 (sx3, each 3H),
7.11 (s, 1H), 7.44 (d, J ) 8.8 Hz, 1H), 7.77 (d, J ) 8.8 Hz, 1H),
7.80 (s, 1H), 8.33 (s, 1H), 8.69 (s, 1H), 11.07 (s, 1H), 11.77 (s,
1H), 12.97 (br, 1H). IR (KBr): 3290, 1684 cm-1. MS (FAB)
m/z: 423 (MH+). HRMS (FAB) for C21H19N4O6 (MH+): calcd,
423.1305; found, 423.1298.
6-Meth oxyisoqu in olin e-3-ca r boxylic Acid (27a ) a n d
8-Met h oxyisoqu in olin e-3-ca r b oxylic Acid (27b). To a
solution of 24 (1.00 g, 5.1 mmol) in 0.5 N NaOH solution (7
mL) was added 37% formaldehyde solution (0.8 mL), and the
mixture was stirred at 37 °C for 27 h. After the reaction
mixture was concentrated in vacuo to one-half volume, con-
centrated HCl (1 mL) was added. The acidic mixture was
concentrated in vacuo, and the residue was dissolved in MeOH
(12 mL). The cooled methanolic solution was saturated with
dry hydrogen chloride and heated at reflux for 2 h. After
concentration in vacuo, the residue was added to cold water.
The aqueous solution was saturated with Na2CO3 and ex-
tracted with ether. The combined organic extracts were washed
with brine, dried over anhydrous Na2SO4, filtered, and then
concentrated in vacuo, giving a mixture of 25a ,b as a yellow
oil (344 mg, 30%). This mixture was directly used for the next
step without separation and collecting analytical data. A
suspension of the mixture of 25a ,b and 10% Pd-C (275 mg)
in xylene (30 mL) was heated at reflux for 3.5 h. After
filtration, the reaction mixture was concentrated in vacuo, and
the residue was separated by flash chromatography (CH2Cl2:
AcOEt ) 7:3) to give 26a as a colorless powder (106 mg, 9.6%
from 24) and 26b as a colorless powder (6.6 mg, 0.6% from
24). 26a : 1H NMR (CDCl3): δ 3.98, 4.06 (sx2, each 3H), 7.21
1
yellow powder (37.1 mg, 8.1% from 28). H NMR (CDCl3): δ
3.99, 4.05 (sx2, each 3H), 7.31 (d, J ) 2.0 Hz, 1H), 7.43 (dd, J
) 8.8 Hz, 2.0 Hz, 1H), 7.88 (d, J ) 8.8 Hz, 1H), 8.52 (s, 1H),
9.23 (s, 1H). 30: 1H NMR (CDCl3): δ 4.01 (s, 3H), 7.34 (d, J )
2.0 Hz, 1H), 7.48 (dd, J ) 8.8 Hz, 2.0 Hz, 1H), 7.94 (d, J ) 8.8
Hz, 1H), 8.60 (s, 1H), 9.10 (s, 1H).
Hydrolysis of the ethyl ester 30 in MeOH in a manner
similar to that described for the preparation of 16d from 19
gave 31 (26.5 mg, 77%). Without collecting further analytical
data, 31 was directly subjected to the next reaction.
5-Meth oxyisoqu in olin e-3-ca r boxylic Acid (35a ). To a
solution of 32a (500 mg, 3.3 mmol) and methyl azidoacetate
(3.80 g, 33 mmol) in MeOH (16 mL) was added NaOMe
solution [prepared from Na (607 mg) in MeOH (6 mL)] at -10
°C, and the mixture was stirred at 0 °C for 17.5 h. After the
reaction was quenched by the addition of ice, the resulting
precipitates were collected by filtration, washed with water,
and dried in vacuo to give 33a as a pale yellow powder (512
mg, 63%). 1H NMR (CDCl3): δ 2.26, 3.83, 3.91 (sx3, each 3H),
6.76 (d, J ) 7.8 Hz, 1H), 6.85 (d, J ) 7.8 Hz, 1H), 7.10 (s, 1H),
7.23 (t, J ) 7.8 Hz, 1H).
This material 33a was directly subjected to the next
reaction. A solution of 33a (500 mg, 2.0 mmol) in xylene (30
mL) was heated at reflux for 9.5 h. After concentration in
vacuo, flash chromatography (CH2Cl2) of the residue gave 34a
(43.3 mg, 10%) and 36a (332 mg). 1H NMR (CDCl3): δ 2.38 (s,
3H), 3.74 (s, 1H).
Without collecting further analytical data, 36a was directly
subjected to the next reaction. A solution of 36a in 1,2-
dichlorobenzene (20 mL) was heated at reflux for 6 h. After
concentration in vacuo, flash chromatography (CH2Cl2) of the
residue gave 34a (total 212 mg, 49%) as a colorless powder.
1H NMR (CDCl3): δ 4.056, 4.064 (sx2, each 3H), 7.09 (d, J )
7.8 Hz, 1H), 7.61 (d, J ) 7.8 Hz, 1H), 7.66 (t, J ) 7.8 Hz, 1H),
8.96 (s, 1H), 9.28 (s, 1H).
Hydrolysis of the ethyl ester 34a (42.0 mg, 0.19 mmol) in
MeOH in a manner similar to that described for the prepara-
tion of 16d from 19 gave 35a (28.3 mg, 73%). Mp: 104-106

1458 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 8
Fukuda et al.
°C. 1H NMR (CDCl3): δ 4.056, 4.064 (sx2, each 3H), 7.09 (d, J
) 7.8 Hz, 1H), 7.61 (d, J ) 7.8 Hz, 1H), 7.66 (t, J ) 7.8 Hz,
1H), 8.96 (s, 1H), 9.28 (s, 1H). IR (KBr): 1727 cm-1. MS (EI)
m/z: 217 (M+). Anal. (C12H11NO3) C, H, N.
(3) (a) Ichimura, M.; Ogawa, T.; Takahashi, K.; Kobayashi, E.;
Kawamoto, I.; Yasuzawa, T.; Takahashi, I.; Nakano, H. Duo-
carmycin SA, a new antitumor antibiotic from streptomyces sp.
J . Antibiot. 1990, 43, 1037. (b) Yasuzawa, T.; Saito, Y.; Ichimura,
M.; Takahashi, I.; Sano, H. Structure of duocarmycin SA, a
potent antitumor antibiotic. J . Antibiot. 1991, 44, 445.
(4) (a) Boger, D. L.; Coleman, R. S.; Invergo, B. J .; Sakya, S. M.;
Ishizaki, T.; Munk, S. A.; Zarrinmayeh, H.; Kitos, P. A.;
Thompson, S. C. Synthesis and evaluation of aborted and
extended CC-1065 functional analogues: (+)- and (-)-CPI-
CDPI3. Preparation of key partial structures and definition of
an additional functional role of the CC-1065 central and right-
hand subunits. J . Am. Chem. Soc. 1990, 112, 4623. (b) Hurley,
L. H.; Warpehoski, M. A.; Lee, C.-S.; McGovren, J . P.; Scahill,
T. A.; Kelly, R. C.; Mitchell, M. A.; Wicnienski, N. A.; Gebhard,
I.; J ohnson, P. D.; Bradford, V. S. Sequence specificity of DNA
alkylation by the unnatural enantiomer of CC-1065 and its
synthetic analogues. J . Am. Chem. Soc. 1990, 112, 4633. (c)
Warpehoski, M. A.; Gebhard, I.; Kelly, R. C.; Krueger, W. C.;
Li, L. H.; McGovren, J . P.; Prairie, M. D.; Wicnienski, N.;
Wierenga, W. Stereoelectronic factors influencing the biological
activity and DNA interaction of synthetic antitumor agents
modeled on CC-1065. J . Med. Chem. 1988, 31, 590. (d) Chin, H.
L.; Dinshaw, J . P. Site-specific covalent duocarmycin A-Intramo-
lecular DNA triplex complex. J . Am. Chem. Soc. 1992, 114,
10658. (e) Boger, D. L.; Ishizaki, T.; Zarrinmayeh, H.; Munk, S.
A.; Kitos, P. A.; Suntornwat, O. Duocarmycin-pyrindamycin
DNA alkylation properties and identification, synthesis, and
evaluation of agents incorporating the pharmacophore of the
duocarmycin-pyrindamycin alkylation subunit. Identification of
the CC-1065-duocarmycin common pharmacophore. J . Am.
Chem. Soc. 1990, 112, 8961. (f) Boger, D. L. Duocarmycins: A
new class of sequence selective DNA minor groove alkylating
agents. Chemtracts: Org. Chem. 1991, 4, 329. (g) Sugiyama, H.;
Hosoda, M.; Saito, I.; Asai, A.; Saito, H. Covalent alkylation of
DNA with duocarmycin A. Identification of abasic site structure.
Tetrahedron Lett. 1990, 31, 7197 and references therein.
(5) McGovren, J . P.; Clarke, G. L.; Pratt, E. A.; DeKoning, T. F.
Preliminary toxicity studies with the DNA-binding antibiotic CC-
1065. J . Antibiot. 1984, 37, 63.
5,6,7-Tr im eth oxyisoqu in olin e-3-ca r boxylic Acid (33b).
The same treatments of 32b (930 mg, 4.4 mmol) as described
for the preparation of 33a gave 33b (552 mg, 41%). IR (KBr):
2126, 1717 cm-1
.
Treatments of 33b (307 mg, 1.0 mmol) in a manner similar
to that described for the preparation of 34a from 33a gave
34b (113 mg, 41%). 1H NMR (CDCl3): δ 4.03, 4.045, 4.054,
4.10 (sx4, each 3H), 7.12 (s, 1H), 8.76 (s, 1H), 9.14 (s, 1H). IR
(KBr): 1711 cm-1. MS (EI) m/z: 277 (M+). HRMS (EI) for
C
14H15NO5 (M+): calcd, 277.0950; found, 277.0961.
Hydrolysis of 34b (65.3 mg, 0.24 mmol) in the same manner
as described for the preparation of 35a from 33a gave 35b
(51.6 mg, 83%). MS (EI) m/z: 263 (M+). HRMS (EI) for C13H13
NO5 (M+): calcd, 263.0794; found, 263.0793. Without collecting
further analytical data, 38b was directly subjected to the next
reaction.
-
5,6,7-Tr im eth oxycin n olin e-3-ca r boxylic a cid (41). To a
solution of 37 (3.66 g, 20 mmol) in water (50 mL) and
concentrated HCl (4.2 mL) was added a solution of NaNO2
(1.73 g, 25 mmol) in water (5 mL) at 2-3 °C, and the mixture
was stirred at the same temperature for 5 min. To a solution
of the diazonium salt were added concentrated HCl (6.7 mL)
and NaBF4 (8.78 g, 80 mmol) at 0 °C, and the mixture was
further stirred for 30 min. The resulting precipitates were
collected by filtration, washed with water, MeOH, and ether,
and then dried in vacuo to give 38 as colorless crystals (4.58
g, 81%). The diazonium salt 38 was used for the next step
without further purification. To a solution of 39 (0.92 g, 5.0
mmol) in MeCN (75 mL) was added 38 (1.41 g, 5.0 mmol) at
room temperature, and the mixture was stirred for 2.5 h. The
reaction mixture was heated at 80 °C for 2 h. After cooling,
the mixture was concentration in vacuo. The residue was
purified by flash chromatography (CH2Cl2:AcOEt ) 4:1) fol-
lowed by washing with ether giving 40 as pale yellow needles
(1.35 g, 93%). Mp: 147-148 °C. 1H NMR (CDCl3): δ 1.52 (t, J
) 7.3 Hz, 3H), 4.06, 4.118, 4.124 (sx3, each 3H), 4.61 (q, J )
14.2 Hz, 7.3 Hz, 2H), 7.72 (s, 1H), 8.78 (s, 1H). IR (KBr): 1712
cm-1. MS (EI) m/z: 292 (M+). Anal. (C14H16N2O5) C, H, N.
Hydrolysis of the ester 40 (292 mg, 1.0 mmol) in a manner
similar to that described for the preparation of 16d from 19
gave 41 as pale yellow crystals (202 mg, 77%). Mp: 195 °C
dec. 1H NMR (DMSO-d6): δ 3.98, 4.07, 4.10 (sx3, each 3H),
7.80 (s, 1H), 8.58 (s, 1H), 13.64 (br, 1H). IR (KBr): 3535, 1608
cm-1. MS (EI) m/z: 264 (M+). Anal. (C12H12N2O5‚3/2H2O) C,
H, N.
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Su p p or tin g In for m a tion Ava ila ble: Synthetic proce-
dures and characterization data for the compounds dl- and
(S)-14, dl- and/or (S)-10a ,b,f,i, dl- and/or (S)-11a ,b,f,i, and (S)-
13b. This information is available free of charge via the
Internet at http://pubs.acs.org.
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