Design, synthesis, and biological activity of novel polycyclic aza-amide FKBP12 ligands

Article abstract of DOI:10.1021/jm049161u

Since the discovery that FK-506 promotes neurite outgrowth, considerable attention has been focused on the development of potent nonimmunosuppressive ligands for FK-506 binding proteins (FKBPs). Such neuroimmunophilin agents have been reported to show neu

Full text of DOI:10.1021/jm049161u

1202
J. Med. Chem. 2006, 49, 1202-1206
Design, Synthesis, and Biological Activity of Novel Polycyclic Aza-Amide FKBP12 Ligands
Raymond A. Hudack, Jr.,† Nancy S. Barta,*,† Chuangxing Guo,§ Judith Deal,§ Liming Dong,§ Lorraine K. Fay,†
Bradley Caprathe,† Arindam Chatterjee,† Darin Vanderpool,| Christopher Bigge,† Richard Showalter,‡ Steve Bender,§
Corinne E. Augelli-Szafran,† Elizabeth Lunney, and Xinjun Hou#
Department of Chemistry, Pfizer Global Research and DeVelopment, Michigan Laboratories, 2800 Plymouth Road, Ann Arbor,
Michigan 48105, Departments of Medicinal Chemistry, Molecular Biology, Biochemistry, and DiscoVery Computation, Pfizer Global Research
and DeVelopment, La Jolla Laboratories, 10770 Science Center DriVe, San Diego, California 92121, and Department of Exploratory Medicinal
Sciences/Chemical Technology, Pfizer Global Research and DeVelopment, Groton Laboratories, Groton, Connecticut 06340
ReceiVed October 19, 2004
Since the discovery that FK-506 promotes neurite outgrowth, considerable attention has been focused on
the development of potent nonimmunosuppressive ligands for FK-506 binding proteins (FKBPs). Such
neuroimmunophilin agents have been reported to show neuroregenerative activity in a variety of cell and
animal models including neurite outgrowth, age-related cognitive decline, Parkinson’s disease, peripheral
nerve injury, optic nerve degeneration, and diabetic neuropathy. We have designed and synthesized a unique
series of tetracyclic aza-amides that have been shown to be potent FKBP12 rotamase inhibitors. The structure-
activity relationships established in this study have demonstrated diverse structural modifications that result
in potent rotamase inhibitory activity.
Introduction
The macrolide lactone FK506 (Tacrolimus) originally isolated
from Streptomyces tsukubaensis has been shown to be a
powerful immunosuppressant agent used to prevent organ
transplant rejection.1,2 FK506 is bifunctional in nature, having
an effector region, responsible for immunosuppression, and a
protein-binding region (Figure 1).3 The proteins that bind FK506
were subsequently named FK506 binding proteins or FKBPs.
In 1994, Snyder, et al. reported that FK506 could promote
neurite outgrowth in PC-12 cells and rat sensory ganglia.4,5
Hamilton, et al. demonstrated that the effector region, respon-
Figure 1. Bifunctional nature of FK506.
sible for the immunosuppressive properties of FK506, was not
required to facilitate neurite outgrowth.6 Small molecule mimics
that maintained interactions with FKBPs, were shown to
promote neurite outgrowth. Since long-term continuous treat-
ment with FK506 has been shown to promote undesirable side
effects, such as immune deficiency, considerable efforts are
underway to develop compounds that elicit neuroprotective and
neurorestorative effects without having immunosuppressant
activity.7-9
disease, Alzheimer’s disease, spinal cord injury, traumatic brain
injury, stroke, diabetic neuropathy, and peripheral neuropathy.
Two key hydrogen bond interactions are evident from the
crystal structure analysis of FK506 complexed with FKBP12
(Figure 1).15-17 The first is the interaction between the backbone
NH of Ile-56 and the pipecolinic ester carbonyl. The second is
a hydrogen bond between the amide carbonyl and Tyr-82.
Additionally, a small hydrophobic, electropositive cavity is
formed by Tyr-26, Phe-36, and Phe-99. Previous work in this
area demonstrated that compound 1 is a potent inhibitor of
FKBP rotamase activity.18 The aim of our current structure-
activity relationship (SAR) studies was to further elucidate the
structural modifications necessary that lead to potent FKBP12
rotamase inhibitory activity.
The mechanism by which neuroimmunophilin ligands elicit
neurite outgrowth is not well understood; however, the ability
to bind FKBPs, in particular FKBP52, does appear to correlate
with neurite outgrowth.10-12 In addition, FKBP12 is known to
facilitate the cis-trans isomerization of peptide linkages adjacent
to proline residues (PPIase or rotamase inhibitory activity).13,14
While not directly associated with neurite outgrowth, rotamase
inhibitory activity does provide a convenient assay for the
binding ability of small molecules to FKBP12. Neuroimmuno-
philin agents capable of promoting neurite outgrowth have a
number of potential therapeutic targets including Parkinson’s
Results and Discussion
Initial structural modifications of compound 1 revolved
around incorporation of a tetrahydroisoquinoline moiety to limit
the flexibility of these compounds in an effort to better match
the hydrophobic binding cavity seen in the FK506-FKBP12
crystal structure complex. The proposed structural motif would
allow the preparation of a number of analogues varying the
substitution of the A and B ring as depicted in Figure 2 for
rapid SAR evaluation.
The novel polycyclic derivatives were prepared in five steps
starting from 2,6-pyridine dicarboxylic acid as shown in Scheme
1. Reduction with Rh/Al followed by protection of the amine
during workup afforded the cis-diacid 2. Treatment with acetic
* To whom correspondence should be addressed. Phone: (734) 622-
1381. Fax: (734) 622-5165. E-mail: nancy.barta@pfizer.com.
† Department of Chemistry.
§ Department of Medicinal Chemistry.
‡ Department of Molecular Biology.
| Department of Biochemistry.
Department of Discovery Computation.
# Department of Exploratory Medicinal Sciences/Chemical Technology.
10.1021/jm049161u CCC: $33.50 © 2006 American Chemical Society
Published on Web 01/14/2006

Brief Articles
Journal of Medicinal Chemistry, 2006, Vol. 49, No. 3 1203
Table 1. Tetrahydroisoquinoline Substitution and the Effect on Activity
Figure 2. Structural modifications for initial SAR exploration.
Scheme 1a
Table 2. Aryl Substitution and the Effect on Activity
a Reagents and conditions: (i) Rh-Al, 50 psi H2, NaOH (aq) followed
by CbzCl; (ii) acetic anhydride, toluene, reflux followed by phenethylamine;
(iii) sodium borohydride, methanol, 0 °C; (iv) trifluroacetic acid, CH2Cl2 0
°C; (v) Li(HBEt3), BF3OEt2; (vi) keto-acid, EDC-HCl, HOBt, triethylamine,
CH2Cl2, 0 °C to room temperature; (vii) R,R-difluoro acid, EDC-HCl,
DMAP, CH3CN; (viii) N-methylmorpholine, sulfonyl chloride, CH2Cl2; (ix)
R2NH, ethyl isocyanate, DMF; (x) ClSO3H, Et3N, CH2Cl2; (xi) 3,5-lutidine,
aniline, CH2Cl2.
anhydride provided the cyclic anhydride that upon workup could
be reacted with a variety of phenethylamines to provide 3a-j.
Partial reduction of the imide could be accomplished by
treatment with sodium borohydride, and the cyclization induced
with trifluoroacetic acid. Benzyl carbamate deprotection afforded
the desired amines 4a-j. Alternatively, a one-pot cyclization/
deprotection was accomplished by addition of trifluoroborane-
etherate to the cyclization reaction, which afforded the desired
template in higher yield and purity compared to the two-step
process. This penultimate intermediate was elaborated to
incorporate a significant number of linker modifications. A
variety of keto-amide, sulfonamide, sulfamide, urea, and R,R-
difluoro amides were prepared and evaluated to determine the
structural requirements necessary to maintain FKBP12 binding.
In an effort to first optimize the substitution of the tetrahy-
droisoquinoline moiety, we chose to preserve the 3,4,5-
trimethoxy substitution on the B-ring and the keto-amide
functionality that had proven successful for compound 1. The
most promising substitution on the A ring was then chosen as
a basis for further SAR exploration of the B ring substitution
and linker modification. The effect of A ring modification on
rotamase activity, exhibited by compounds 5a-j, is highlighted
in Table 1. Incorporation of a variety of substituents resulted
in less than a 4-fold difference in activity with the 6,8-dimethoxy
derivative, 5a, being most potent at 69 nM.
Figure 3. Effects of oxidation state on activity.
surrounding the keto-amide functionality. A variety of substitu-
tions were made on the B-ring system to provide 6a-r (Table
2). The 3,4-di-Cl derivative, 6a, proved one of the most active
at 34 nM. Incorporation of bulky substituents, such as 3,5-di-
t-bu-4-OH in 6r, led to a decrease in activity. In general, meta/
para substitution was favored over ortho substitution for the
compounds tested. A variety of heterocyclic replacements for
the simple aromatic ring in 7a-e proved to be potent rotamase
inhibitors (Table 3).
The keto-amide motif was retained from FK506 in previous
work due to the hydrogen bond between the amide carbonyl
and Tyr-82 in the FK506-FKBP12 crystal structure. In an effort
to explore the necessity of the keto-amide in the polycyclic
structures, we synthesized compounds 8 and 9. Activity
diminished as the oxidation state of the R-carbon decreased
(Figure 3). However, R,R-difluoro substitution resulted in com-
pound 10, which is nearly equipotent to keto-amide 5a; this is
an analogous result to what was seen with 2-aryl-2,2-difluoro-
acetamide proline and pipecolate derivatives (Figure 4).19
The necessity of other possible sites of hydrogen bonding
interactions was tested. Compound 11 was synthesized by LAH
After determining that the 6,8-dimethoxy substitution of the
tetrahydroisoquinoline was most active, we explored the SAR

1204 Journal of Medicinal Chemistry, 2006, Vol. 49, No. 3
Brief Articles
Table 5. Effects of Incorporation of a Urea Linkage
Figure 4. R,R-Difluoro substitution and the effect on activity.
Table 6. Effects of Incorporation of a Sulfamide Linkage
Figure 5. Effects of removing a hydrogen bond acceptor.
Table 3. Aryl Replacement and the Effect on Activity
Table 4. Effects of Incorporation of a Sulfonamide Linkage
levels of activity (Table 5). Last, the incorporation of a sulfamide
linkage was explored. A number of analogues 14a-j exhibited
potent activity (Table 6).
Conclusions
Extensive SAR exploration of a polyclic aza-amide has
identified many compounds with potent FKBP12 rotamase
inhibitory activity. Incorporation of a rigid tetrahydroisoquino-
line framework resulted in several compounds with increased
activity compared to previous studies. Replacement of the keto-
amide functionality by a sulfonamide or sulfamide linkage
proved successful.
Experimental Section
Biochemistry. Compounds were evaluated for their ability to
inhibit FKBP12 rotamase activity via the following procedure. In
a quartz cuvette, a final 1 mL buffer concentration was reached
(50 mM Hepes, 100 mM NaCl, pH 8.0). Within this final reaction
volume, 3.5 µL of 20 µM FKBP-12 (in 50 mM Hepes, 100 mM
NaCl, pH 8.0) and 10 µL of test compound in DMSO were added.
The reaction was initiated by adding 10 µL of chymotrypsin (100
mg/mL in 1 mM HCl) followed by 5 µL (4-10 mM succinyl-Ala-
Leu-Pro-Phe-pNA in 240 mM LiCl/TFE) at 15 °C. The absorbance
at 390 nM versus time was monitored for up to 400 s. Rate constants
were generated from the absorbance versus time plots at 8-12
compound concentrations. Additionally, a no enzyme control rate
constant was determined. The Kiapp was determined from the
corrected rate constants using an IC50 equation or a tight-binding
equation by Morrison.20 Typical error in measurement of the Kiapp
was less than 25%.
reduction of the penultimate amine derivative followed by
standard coupling conditions. The loss of this hydrogen bond
acceptor site resulted in nearly complete loss of rotamase
inhibitory activity (Figure 5). Further SAR investigations
preserved this key site of oxidation.
An alternative to the keto-amide was explored with the
intention of maintaining hydrogen-bonding possibility. A series
of compounds 12a-j were synthesized via coupling of the
penultimate amine with a sulfonyl chloride in the presence of
base. The sulfonamide proved to be an effective replacement,
as all compounds demonstrated respectable levels of rotamase
activity (Table 4). In an analogous fashion, a urea linkage was
introduced in compounds 13a-e by treatment of the amine with
an isocyanate. This series of compounds demonstrated decreased
The syntheses of compounds 2, 3a-c, 3e, 3i, 3j, 4a-c, 4e, 4j,
5c, 8-11, 12a-j, 13a-e, and 14a-j have previously been
described.21,22

Brief Articles
Journal of Medicinal Chemistry, 2006, Vol. 49, No. 3 1205
General Procedure A for Synthesis of 3a-j. A suspension of
2 (1.0 equiv) in acetic anhydride (0.08 M) was heated at 65 °C for
30 min. The mixture was cooled to RT and concentrated, dissolved
in 20 mL of toluene, and concentrated again. The toluene treatment
was repeated three additional times to remove all traces of acetic
anhydride. The residual oil was dissolved in toluene (0.45 M), and
the desired phenethylamine (1.1 equiv) was added and stirred for
1.5 h at RT. Acetic anhydride (5 M with respect to phenethylamine)
was added and stirred at RT for 16 h. The reaction mixture
concentrated to an oil and purified by MPLC (hexane/ethyl acetate
gradient 90:10 to 40:60). Fractions containing the desired product
were combined and concentrated to give the desired product as an
oil.
was stirred at 0 °C for 1 h, the mixture was allowed to warm to
RT over 15 h and then was partitioned between NaHCO3 (sat’d
aq.) and EtOAc. The combined organics were washed with water
and then brine, dried, and concentrated. The residual oil was purified
on silica using a gradient of (1:1) to (3:1) EtOAc/hexanes as eluent.
The desired fractions were combined and concentrated. The residue
was taken up in EtOAc/MeOH (1:1) and treated with a catalytic
amount of Pd on carbon (10%) and stirred under a hydrogen
atmosphere for 2 h. The mixture was filtered through Celite and
the filtrate concentrated to give 4i in an overall 26% yield. This
material was subsequently used without further purification.
General Procedure C for Synthesis of 5a-j, 6a-r, 7a-e. A
solution of 4 (1.0 equiv) in CH
2Cl2 was treated sequentially with
3-[2-(4-Chloro-phenyl)-ethyl]-2,4-dioxo-3,9-diaza-bicyclo[3.3.1]-
nonane-9-carboxylic acid benzyl ester (3d). 1.96 g (68%). H
NMR (400 MHz, CDCl3) δ ppm 1.37 (m, 2 H), 1.77 (m, 3 H),
1.92 (m, 2 H), 2.78 (t, J ) 7.69 Hz, 2 H), 3.96 (m, 2 H), 4.93 (m,
2 H), 5.14 (s, 2 H), 7.12 (d, J ) 8.55 Hz, 2 H), 7.21 (m, 2 H), 7.33
(s, 5 H). MS (APCI) m/z 427.1 (M+ + 1).
the appropriate acid (1.2 equiv), EDC‚HCl (1.2 equiv), HOBt (1.2
equiv), and Et3N (1.2 equiv) at RT, and stirred overnight. The
reaction mixture was concentrated onto silica gel, and purified by
MPLC (hexane/ethyl acetate 90:10-40:60). Fractions containing
the desired compounds were combined and concentrated to give
the desired product.
1
3-[2-(2-Chloro-phenyl)-ethyl]-2,4-dioxo-3,9-diaza-bicyclo[3.3.1]-
nonane-9-carboxylic acid benzyl ester (3f). 4.59 g (79%). MS
(APCI) m/z 427.1 (M+ + 1).
3-[2-(3-Chloro-phenyl)-ethyl]-2,4-dioxo-3,9-diaza-bicyclo[3.3.1]-
nonane-9-carboxylic acid benzyl ester (3g). 2.52 g (87%). MS
(APCI) m/z 427.1 (M+ + 1).
3-[2-(3-Fluoro-phenyl)-ethyl]-2,4-dioxo-3,9-diaza-bicyclo[3.3.1]-
nonane-9-carboxylic acid benzyl ester (3h). 4.22 g (76%). MS
(APCI) m/z 411.1 (M+ + 1).
General Procedure B for Synthesis of 4a-j. A solution of 3
in THF (0.2 M) was cooled to -78 °C prior to addition of Li-
(HBEt3) (1.7 equiv). After 30 min at -78 °C, methanol was added,
and the reaction mixture was warmed to 0 °C. After 10 min,
NaHCO3 (sat’d aq.) and 30% H2O2 were added and the sample
was stirred for 30 min at RT. The solution was concentrated, diluted
with water, extracted with CH2Cl2, and the organics were combined,
dried, and concentrated. The residual oil was taken up in dry CH2-
Cl2 and TFA (0.02 M) was added and the sample was stirred for
15 h. BF3‚OEt2 was added, and the mixture was stirred until ring
closure and deprotection were complete as determined by mass
spectrometry. The reaction mixture was then neutralized with
NaHCO3 (sat’d aq.), extracted with CH2Cl2, dried and concentrated
onto silica, and purified by MPLC (CH2Cl2/MeOH 99:1 to 70:30).
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,5,6,9,10,11,-
12,13,13a-octahydro-2-chloro (4d). 0.323 g (90%). 1H NMR (400
MHz, DMSO-d6) δ ppm 1.56 (m, 1 H), 1.68 (m, 1 H), 1.84 (m, 1
H), 1.97 (m, 2 H), 2.09 (m, 1 H), 2.73 (m, 1 H), 2.83 (m, 1 H),
3.06 (m, 1 H), 3.86 (m, 1 H), 4.50 (m, 2 H), 4.96 (s, 1 H), 7.20 (d,
J ) 8.06 Hz, 1 H), 7.30 (d, J ) 8.06 Hz, 1 H), 7.56 (s, 1 H). MS
(APCI) m/z 277.0 (M+ + 1).
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,5,6,9,10,11,-
12,13,13a-octahydro-4-chloro (4f). 1.08 g (60%). MS (APCI) m/z
276.9 (M+ + 1).
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,5,6,9,10,11,-
12,13,13a-octahydro-3-chloro (4g). 1.31 g (99%). MS (APCI) m/z
277.0 (M+ + 1).
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,5,6,9,10,11,-
12,13,13a-octahydro-1-fluoro (4h). 1.29 g (75%). MS (APCI) m/z
261.0 (M+ + 1).
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,5,6,9,10,11,-
12,13,13a-octahydro (4i). A solution of 3i in MeOH (0.065 M)
was cooled to -5 °C prior to portion-wise addition of NaBH4 (2.5
equiv) over 30 min. The sample was warmed to RT over 1 h,
acidified to pH 2 by dropwise addition of HCl (4 N in dioxane),
and stirred for 2 h. A small portion of Na2CO3 (sat’d aq.) was added,
and the mixture was then concentrated, diluted with NaHCO3 (sat’d
aq.), and extracted with EtOAc. The combined organics were
washed with NH4Cl (sat’d aq.) and then brine, dried, and concen-
trated. The residual oil was purified by flash chromatography on
silica using EtOAc/Hexanes (1:1) as eluent. The desired fractions
were combined and concentrated, and the residual oil was taken
up in dry CH2Cl2/TFA (1:2) and cooled to 0 °C. After the sample
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-1,3-dimethoxy (5a). 0.407 g (47%). 1H NMR (major rotamer,
400 MHz, CDCl3) δ ppm 1.85-2.02 (m, 4 H), 2.13 (s, 1 H), 2.49
(s, 1 H), 2.66 (s, 1 H), 2.90 (s, 1 H), 3.50 (s, 3 H), 3.64 (s, 3 H),
3.73 (s, 6 H), 3.89 (s, 3 H), 4.57 (s, 1 H), 4.86 (s, 1 H), 5.15 (s, 1
H),5.65 (s, 1 H), 6.04 (s, 1 H), 6.71 (s, 2 H), 7.24 (s, 2 H). MS
(APCI) m/z 525.2 (M+ + 1). Anal. (C28H32N2O8) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-2-methyl (5b). 0.127 g (68%). MS (APCI) m/z 479.1 (M+
+
1). Anal. (C27H30N2O6) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-2-chloro (5d). 0.073 g (51%). MS (APCI) m/z 499.0 (M+
1). Anal. (C26H27ClN2O6‚0.36CH3OH) C, H, N.
+
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-3-methoxy (5e). 0.19 g (83%). MS (APCI) m/z 495.2 (M+
1). Anal. (C27H30N2O7‚0.2H2O) C, H, N.
+
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-4-chloro (5f). 0.058 g (30%). MS (APCI) m/z 499.1 (M+
1). Anal. (C26H27ClN2O6‚0.15C6H14‚0.25CH2Cl2) C, H, N.
+
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-3-chloro (5 g). 0.173 g (64%). MS (APCI) m/z 498.0 (M+
1). Anal. (C26H27ClN2O6‚0.07CH2Cl2) C, H, N.
-
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-1-fluoro (5h). 0.086 g (46%). MS (APCI) m/z 483.2 (M+
1). Anal. (C26H27FN2O6‚0.15CH2Cl2‚0.3C4H8O) C, H, N.
+
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro (5i). 0.120 g (31%). MS (APCI) m/z 465.2 (M+ + 1). Anal.
(C26H28N2O6‚0.2 H2O) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4,5-trimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahy-
dro-2-fluoro (5j). 0.073 g (53%). MS (APCI) m/z 483.1 (M+
1). Anal. (C26H27FN2O6‚0.8H2O) C, H, N.
+
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4-dichloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6a). 0.042 g (31%). MS (APCI) m/z 503.0 (M+ + 1).
Anal. (C25H24Cl2N2O5) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,5-dimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-
1,3-dimethoxy (6b). 0.058 g (45%). MS (APCI) m/z 495.1 (M+ +
1). Anal. (C27H30N2O7) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3-chloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-
1,3-dimethoxy (6c). 0.057 g (36%). MS (APCI) m/z 469.1 (M+
1). Anal. (C25H25Cl1N2O5‚0.05C6H14) C, H, N.
+

1206 Journal of Medicinal Chemistry, 2006, Vol. 49, No. 3
Brief Articles
(2) Kino, T.; Hatanaka, H.; Hashimoto, M.; Nishyama, M.; Goto, T.;
Okuhara, M.; Kohsaka, M.; Aoki, H.; Imanaka, H. FK-506, a novel
immunosuppressant isolated from a Streptomyces. J. Antibiot. 1987,
40, 1249-1255.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,4-dimethoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-
1,3-dimethoxy (6d). 0.044 g (34%). MS (APCI) m/z 495.1 (M+ +
1). Anal. (C27H30N2O7‚0.50CH2Cl2) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(4-
bromo)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6e). 0.058 g (36%). MS (APCI) m/z 515.0 (M+ + 1).
Anal. (C25H25BrN2O5‚0.15CH2Cl2) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(4-
chloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6f). 0.033 g (21%). MS (APCI) m/z 469.1 (M+ + 1).
Anal. (C25H25ClN2O5‚0.75H2O) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-dimethoxy
Name (6 g). 0.13 g (38%). MS (APCI) m/z 435.2 (M+ + 1). Anal.
(C25H26N2O5) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(4-
fluoro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6h). 0.020 g (9%). MS (APCI) m/z 453.2 (M+ + 1).
Anal. (C25H25FN2O5‚1.20H2O‚0.15C6H14) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(4-
ethyl)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6i). 0.044 g (28%). MS (APCI) m/z 463.1 (M+ + 1).
Anal. (C27H30N2O5‚0.05H2O) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(4-
methoxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6j). 0.036 g (23%). MS (APCI) m/z 465.1 (M+ + 1).
Anal. (C26H28N2O6‚0.15C4H8O2) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(2,5-dichloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6k). 0.063 g (19%). MS (APCI) m/z 503.0 (M+ + 1).
Anal. (C25H24Cl2N2O5‚0.05C6H14) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(2-
hydroxy)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6l). 0.123 g (55%). MS (APCI) m/z 451.2 (M+ + 1).
Anal. (C25H26N2O6‚0.30H2O) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(2,3-dichloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6m). 0.052 g (32%). MS (APCI) m/z 503.0 (M+ + 1).
Anal. (C25H24Cl2N2O5‚0.45C6H14) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(2-
chloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6n). 0.049 g (31%). MS (APCI) m/z 469.1 (M+ + 1).
Anal. (C25H25Cl1N2O5‚0.05C6H14‚0.15H2O) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(2,4-dichloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6o). 0.012 g (12%). MS (APCI) m/z 503.1 (M+ + 1).
Anal. (C25H24Cl2N2O5‚0.6C6H14‚0.15H2O‚0.30CH2Cl2) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-(4-
diethylamino)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-
1,3-dimethoxy (6p). 0.054 g (13%). MS (APCI) m/z 506.2 (M+ +
1). Anal. (C29H35N3O5‚0.15C6H14‚0.30H2O) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(2,5-dichloro)phenylacetate]-5,6,9,10,11,12,13,13a-octahydro-1,3-
dimethoxy (6q). 0.062 g (10%). MS (APCI) m/z 503.0 (M+ + 1).
Anal. (C25H24Cl2N2O5‚0.45C6H14) C, H, N.
9,13-Imino-8H-azocino [2,1-a] isoquinolin-8-one,14-[2-oxo-
(3,5-di-tert-butyl-4-hydroxy)phenylacetate]-5,6,9,10,11,12,13,13a-
octahydro-1,3-dimethoxy (6r). 0.058 g (39%). MS (APCI) m/z
563.2 (M+ + 1). Anal. (C33H42N2O6‚0.07H2O) C, H, N.
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Supporting Information Available: Experimental details
for 7a-7e and combustion analysis of the final compounds.
This material is available free of charge via the Internet at
http://pubs.acs.org.
References
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JM049161U