Solution-phase synthesis of novel linear oxyamine combinatorial libraries with antibacterial activity

Article abstract of DOI:10.1021/jo971655u

Use of solution phase combinatorial library synthesis led to the discovery of several oxyaminecontaining antibacterial compounds. Solution-phase simultaneous addition of meta-substituted benzyl bromides and 'fix-last' combinatorial strategies were used to prepare libraries. Additional structure-activity relationship studies were conducted by reductive cleavage of the oxyamine moiety and led to loss of antibacterial activity. Several single compounds were designed and synthesized on the basis of library screening results and were shown to have antibacterial activity.

Full text of DOI:10.1021/jo971655u

1846
J . Org. Chem. 1998, 63, 1846-1852
Solu tion -P h a se Syn th esis of Novel Lin ea r Oxya m in e
Com bin a tor ia l Libr a r ies w ith An tiba cter ia l Activity
Pei-Pei Kung,* Ramesh Bharadwaj, Allister S. Fraser, Daniel R. Cook,
Andrew M. Kawasaki, and P. Dan Cook
Isis Pharmaceuticals, Inc., 2292 Faraday Avenue, Carlsbad, California 92008
Received September 5, 1997
Use of solution phase combinatorial library synthesis led to the discovery of several oxyamine-
containing antibacterial compounds. Solution-phase simultaneous addition of meta-substituted
benzyl bromides and “fix-last” combinatorial strategies were used to prepare libraries. Additional
structure-activity relationship studies were conducted by reductive cleavage of the oxyamine moiety
and led to loss of antibacterial activity. Several single compounds were designed and synthesized
on the basis of library screening results and were shown to have antibacterial activity.
In tr od u ction
Strategies to enhance drug discovery by devising,
synthesizing, and screening combinatorial libraries in a
high-throughput process are undergoing a very active
phase of development.1,2 Initial combinatorial libraries
were prepared by solid-phase techniques.1,2 Although
solution-phase synthesis of combinatorial libraries is a
relatively unexplored area, we believe such techniques
provide some advantages over solid-phase synthesis.3-5
One of our recent approaches in this area is to synthesize
combinatorial libraries in solution-phase by adding groups
of functionalities in a simultaneous manner.5 As we
desired to search for novel pharmacophores, we elected
to base our combinatorial libraries on novel structures
rather than known pharmacophore structures typically
targeted in most combinatorial chemistries.6-8 In addi-
tion, we desired to rapidly search novel structure space
F igu r e 1.
with a variety of scaffolds selected to provide various
shapes (footprints). We sought to design and synthesize
libraries containing molecules possessing either confor-
mational constraints or flexibilities before the active
conformer is known. If needed, structure-activity rela-
tionship studies could subsequently be performed on the
basis of the information obtained from an active library.
In previous work, a series of libraries was generated from
unsymmetrical polyazaphane scaffolds.5 In the present
work, we selected the linear scaffold (Figure 1, 1) for
combination with meta-substituted benzyl bromides in
order to investigate a totally different structure space.
This scaffold has an oxyamine group and a primary
alkylamine as combinatorial sites. In this paper, we
describe the design and synthesis of the linear scaffold
followed by the synthesis of several linear oxyamine
combinatorial libraries utilizing solution-phase synthesis
techniques.5b
(1) (a) Still, W. C. Acc. Chem. Res. 1996, 29, 155. (b) Ostresh, J . M.;
Husar, G. M.; Blondelle, S. E.; Dorner, B.; Weber, P. A.; Houghten, R.
A. Proc. Natl. Acad. Sci. U.S.A. 1994, 91, 11138. (c) Ohlmeyer, M. H.
J .; Swanson, R. N.; Dillard, L. W.; Reader, J . C.; Asouline, G.;
Kobayashi, R.; Wigler, M.; Still, W. C. Proc. Natl. Acad. Sci. U.S.A.
1993, 90, 10922.
(2) (a) Armstrong, R. W.; Combs, A. P.; Tempest, P. A.; Brown, S.
D.; Keating, T. A. Acc. Chem. Res. 1996, 29, 123 and references therein.
(b) Keating, T. A.; Armstrong, R. W. J . Am. Chem. Soc. 1996, 118,
2574. (c) Goebel, M.; Ugi, I. Tetrahedron Lett. 1995, 36, 6043.
(3) (a) Boger, D. L.; Tarby, C. M.; Myers, P. L.; Caporale, L. H. J .
Am. Chem. Soc. 1996, 118, 2109. (b) McDevitt, J . P.; Lansbury, P. T.,
J r. J . Am. Chem. Soc. 1996, 118, 3818.
Resu lts a n d Discu ssion
(4) Curran, D. P.; Hoshino, M. J . Org. Chem. 1996, 61, 6480.
(5) (a) An, H.; Cummins, L. C.; Griffey, R. H.; Bharadwaj, R.; Haly,
B. D.; Fraser, A. S.; Wilson-Lingardo, L.; Risen, L. M.; Wyatt, J . R.;
Cook, P. D. J . Am. Chem. Soc. 1997, 119, 3696. (b) Kung, P.-P.; Cook,
P. D. Combinatorial Chem. 1998, in press.
(6) (a) Bunin, B. A.; Ellman, J . A. J . Am. Chem. Soc. 1992, 114,
10997. (b) Bunin, B. A.; Plunkett, M. J .; Ellman, J . A. Proc. Natl. Acad.
Sci. U.S.A. 1994, 91, 4708. (c) Plunkett, M. J .; Ellman, J . A. J . Am.
Chem. Soc. 1995, 117, 3306. (d) Koh, J . S.; Ellman, J . A. J . Org. Chem.
1996, 61, 4494.
(7) (a) Dewitt, S. H.; Kiely, J . S.; Stankovic, C. J .; Schroeder, M. C.;
Reynolds Cody, D. M.; Pavia, M. R. Proc. Natl. Acad. Sci. U.S.A. 1993,
90, 6909. (b) McDonald, A. A.; Dewitt, S. H.; Hogan, E. M.; Ramage,
R. Tetrahedron Lett. 1996, 37, 4815. (c) Dressman, B. A.; Spangle, L.
A.; Kaldor, S. W. Tetrahedron Lett. 1996, 37, 937. (d) Hutchins, S. M.;
Chapman, K. T. Tetrahedron Lett. 1996, 37, 4865.
(8) (a) Ruhland, B.; Bhandari, A.; Gordon, E. M.; Gallop, M. A. J .
Am. Chem. Soc. 1996, 118, 253. (b) Gordeev, M. F.; Patel, D. V.; Gordon,
E. M. J . Org. Chem. 1996, 61, 924. (c) Gordeev, M. F.; Patel, D. V.;
Wu, J .; Gordon, E. M. Tetrahedron Lett. 1996, 37, 4643. (d) Norman,
T. C.; Gray, N. S.; Koh, J . T.; Schultz, P. G. J . Am. Chem. Soc. 1996,
118, 7430. (e) Kolodziej, S. A.; Hamper, B. C. Tetrahedron Lett. 1996,
37, 5277.
Prior to library synthesis, the alkylation reaction of the
oxyamine group was investigated by two model studies
(Scheme 1). Treatment of O-methylhydroxylamine with
excess benzyl bromide at room temperature followed by
consumption of unreacted halide with 3-mercaptopropane
sulfonate and liquid-liquid extraction provided the cor-
responding monoalkylated hydroxylamine product (2a )
in 67% yield. Compound 2a was isolated as the hydro-
chloride salt due to the volatility of the free amine.
Additional coupling of the monoalkylated product with
benzyl bromide did not proceed at an appreciable rate at
room temperature, as evidenced by the absence of higher
molecular weight peaks in the mass spectrum of the
crude reaction mixture. However, refluxing at 80 °C for
12 h exclusively gave the corresponding dialkylated
product (2b, 53%) with no evidence of quaternary amine
formation. This result demonstrated that the degree of
S0022-3263(97)01655-1 CCC: $15.00 © 1998 American Chemical Society
Published on Web 02/18/1998

Linear Oxyamine Combinatorial Libraries
J . Org. Chem., Vol. 63, No. 6, 1998 1847
Sch em e 1
Sch em e 2
alkylation could be controlled by the reaction conditions.
For comparison, an attempt was made to prepare 2a by
Schiff base formation with benzaldehyde followed by
reduction. However, removal of excess benzaldehyde
from the reaction mixture was not as efficient as the
sulfonate-mediated purification described above, thus
precluding the use of Schiff base chemistry in our library
synthesis. We also investigated the alkylation reaction
with more reactive alkylating agents (R-bromoaceta-
mides) using a commercially available secondary oxyamine
derivative (N,O-dimethylhydroxylamine) as the substrate
and employing the same quenching and purification
procedure described for the preparation of 2a and 2b
above. The expected tertiary oxyamines (Scheme 1, 3
and 4) were obtained in 76% and 51% yields, respectively.
No corresponding quaternary salts were isolated in these
cases nor indicated by mass spectral analysis of the crude
reaction mixtures. Having completed the model studies,
we then sought to prepare oxyamine-containing combi-
natorial libraries based on the linear scaffold, compound
1.
Ta ble 1. An tiba cter ia l Activity Scr een in g Resu lts of th e
F ir st Rou n d Libr a r ies a ga in st On e Gr a m -P ositive Str a in
(S. pyogen es ATCC#14289) a n d On e Gr a m -Nega tive Str a in
(E. coli im p -)
minimum inhibition concentration, µM
The synthesis of scaffold 1 is shown in Scheme 2.
3-Amino-1-propanol was monobenzylated by treatment
with benzaldehyde in the presence of trimethyl ortho-
formate followed by reduction with sodium borohydride
to afford 5 in excellent yield (93%).9 Coupling of 5 and
N-(2-bromoethyl)phthalimide in the presence of potas-
sium carbonate and catalytic potassium iodide gave 6 in
56% yield. The benzyl group on the secondary amine of
6 was deprotected by hydrogenation and reprotected with
di-tert-butyl dicarbonate (7 and 8; 68% and 95% yields,
respectively). The oxyamino functionality was introduced
onto 8 to give 9 by Mitsunobu reaction. Deprotection of
9 by treatment with hydrazine afforded scaffold 1 in 98%
yield.
compd no.
S. pyogenes
E. coli
1
10
11
12
13
14
>100
>100
5-10
>100
>100
>100
>100
>100
5-25
>100
>100
>100
the process of library synthesis. Libraries were gener-
ated by solution phase simultaneous additions of meta-
substituted benzyl bromides to scaffold 1 (Scheme 3) and
purified by the solution phase purification procedure
described for the model studies above. Successful prepa-
ration of the libraries was confirmed by electrospray
ionization mass spectrometry (ES/MS), which indicated
the presence of the desired products. Subsequently, five
tertiary amine libraries (Scheme 3, 10-14) derived from
scaffold 1 were generated via the solution-phase tech-
niques described above.
A “fix-last” combinatorial method5,10 was devised to
minimize the chemical reactions required to prepare the
initial libraries. The tert-butyl carbamate group on the
scaffold serves as a protecting group of an independent
combinatorial site which could be functionalized last in
Antibacterial activity screening results against one
Gram-positive strain (Streptococcus pyogenes) and one
Gram-negative strain (Escherichia coli, imp-) of the
first round libraries (libraries 10-14) as well as scaffolds
(9) Look, G. C.; Murphy, M. M.; Campbell, D. A.; Gallop, M. A.
Tetrahedron Lett. 1995, 36, 2937.
(10) Pinilla, C.; Appel, J . R.; Blanc, P.; Houghten, R. A. BioTech-
niques 1992, 13, 901, 904.

1848 J . Org. Chem., Vol. 63, No. 6, 1998
Kung et al.
Sch em e 3
Sch em e 5
Sch em e 4
Sch em e 6
1 are listed in Table 1. The antibacterial activities were
measured in solution by minimum inhibition concentra-
tion (MIC) of bacterial growth. One sublibrary prepared
from scaffold 1 (library 11) exhibited potent antibacterial
activity. Instead of performing deconvolution of library
11, the initial structure-activity relationship (SAR)
studies were performed on the library mixture or by the
synthesis of several single compounds (Scheme 4, 15;
Scheme 5, 16-22, 23-29; Scheme 6, 30, 31).
The oxyamine group of scaffold 1 allowed the SAR
studies to be performed on the library mixture to
investigate the importance of the benzyl moiety for
antibacterial activity. Accordingly, the oxyamine bond
of scaffold 1 was reductively cleaved by refluxing the
library mixture (library 11) with 1 M BH3/THF to
generate a new library (library 15). The antibacterial
activities of these two libraries are compared in Table 2.
Library 15 was five to 10-fold less active against tier 1
bacterial strains. Therefore, through library SAR stud-
ies, we believe the benzyl functionality on the oxyamino
group is essential to maintain antibacterial activity.
Nine single compounds, including three from the active
sublibrary (library 11) and six SAR compounds, were
subsequently synthesized (Schemes 5 and 6). These SAR
studies sought to optimize the stereoelectronic effects of
the benzyl moiety. For this purpose, the remainder of
the molecule was held constant as the active components
in the active library (library 11). Among these six SAR
compounds, two of them were synthesized in the combi-
natorial fashion by utilizing the differing reactivities of

Linear Oxyamine Combinatorial Libraries
J . Org. Chem., Vol. 63, No. 6, 1998 1849
Ta ble 2. An tiba cter ia l Activity Scr een in g Resu lts for Va r iou s Libr a r ies a ga in st Gr a m -P ositive a n d
Gr a m -Nega tive Str a in s
minimum inhibition concentration, µM
compd
no.
S. pyrgenes
S. pyogenes
S. aureus
E. faecalis
E. coli
K. pneumoniae
ATCC#13883
C. albicans
ATCC#10231
ATCC#14289 E. coli imp- ATCC#49399 ATCC#25923 ATCC#29212 ATCC#11775
11
15
23
24
25
26
27
28
29
30
31
5-10
25-50
2.5-5
2.5-5
25-50
1-5
5-25
∼50
5-10
2.5-5
25-50
5-25
10-20
>50
3-6
6-12
3-6
2-12
6-12
12-25
6-12
6-12
>100
>100
>100
12-25
>100
>100
>40
12-25
6-12
>100
>100
>100
>50
>50
>50
>100
>20
>100
>20
the oxyamine moiety toward sp2 and sp3 carbons11 in
order to incorporate the acyl moiety of the benzyl group
into the active compound, 23 (Scheme 6, 31). The
structures of these two compounds were determined by
both the ES/MS and MS/MS techniques. Four of the nine
compounds (23, 24, 26, 27) exhibited potent antimicrobial
activities in the low micromolar range as listed in Table
2. The active compounds were also screened against
other wild-type bacterial strains, such as Staphylococcus
aureus, Enterococcus faecalis, and Klebsiella pneumoniae
(Table 2). The specificity of these compounds was
measured by the minimum inhibition concentration of
the growth of the yeast cell Candida albicans.
Compounds 23, 24, and 26 showed equivalent or better
activities compared with the library mixture, 11. Com-
pound 27 showed specificity for S. aureus. Two of the
three single compounds in the original active pool, benzyl
derivative 23 and m-methyl benzyl derivative 24, showed
interesting activities. The third compound, m-trifluo-
romethyl benzyl derivative 25, however, was approxi-
mately 5-fold less active. Other different substituents
on the benzyl moiety such as 3,4-dichloro derivative 28
and the o-methyl benzyl-containing compound 29 did not
show inhibition against either Gram-positive or Gram-
negative strains up to 50 µM. More importantly, among
the active compounds, different specificity against dif-
ferent bacterial strains was observed, depending on the
nature of the substituents on the benzyl moiety.
exception. The specific benzyl bromide (m-methoxy benzyl
bromide) used to synthesize compound 29 was prepared by
the literature procedure.12 Flash column chromatography13
was performed using silica gel 60 (Merck Art 9385). Mass
spectra were acquired using an electrospray ionization source
in both positive and negative modes. MS/MS data were
obtained by isolating ions of interest in a 1.5 amu window
using resonance ejection. The bacterial and yeast antigrowth
assays were performed in 96-well plate format in 150 µL
volume in the presence of library or relevant antibiotic or
antifungal controls.14 Growth was monitored at 24 h for
antibacterial assays and at 48 h for antifungal assays by
measuring absorbance at 595 nm. The S. pyogenes strain was
ATCC#14289 and was grown in 1× Todd-Hewitt broth. The
E. coli imp- strain was a kind gift from Spencer Bensen and
was grown in 1/2× LB.15 The C. albicans was ATCC#10231
and was grown in YM media.
N-Ben zyl-O-m eth ylh ydr oxylam in e Hydr och lor ide (2a).
O-Methylhydroxylamine (0.25 g, 3 mmol) was dissolved in THF
(20 mL), and benzyl bromide (1.4 mL, 12 mmol) and diisopro-
pylethylamine (3.2 mL, 18 mmol) were added sequentially. The
mixture was stirred at room temperature for about 12 h.
3-Mercapto-1-propanesulfonic acid sodium salt (2.2 g, 12.3
mmol) and potassium carbonate (3.5 g, 25 mmol) were then
added, and the mixture was stirred for 2 h and concentrated
in vacuo. The residue was partitioned between H2O (30 mL)
and Et2O (2 × 30 mL). The organic layer was washed with
saturated NaCl (20 mL) and added to 5 mL of 12 M HCl. After
stirring for 1 h, the mixture was then diluted with H2O (30
mL) and poured into a separatory funnel to get layer separa-
tion. The aqueous layer was then collected and concentrated
in vacuo to give 346 mg (66.5% yield) of the title compound:
TLC (Rf ) 0.5; 20% EtOAc/hexanes); 1H NMR (DMSO-d6) δ
3.85 (s, 3H), 4.40 (s, 2H), 7.50 (m, 5H), 12.10 (br, 1H); 13C NMR
(DMSO-d6) δ 137.8, 130.4, 128.7, 128.3, 60.6, 51.6.
Con clu sion
N,N-Diben zyl-O-m eth ylh yd r oxyla m in e (2b). O-Meth-
ylhydroxylamine (0.25 g, 3 mmol) was dissolved in THF (20
mL), and benzyl bromide (1.4 mL, 12 mmol) and diisopropy-
lethylamine (3.2 mL, 18 mmol) were added sequentially. The
mixture was stirred at 80 °C for 12 h. 3-Mercapto-1-propane-
sulfonic acid sodium salt (2.2 g, 12.3 mmol) and potassium
carbonate (3.5 g, 25 mmol) were then added, and the mixture
was stirred for 2 h and concentrated in vacuo. The residue
was partitioned between H2O (30 mL) and Et2O (2 × 30 mL).
The organic layer was separated, washed with brine (1 × 10
mL), and dried over Na2SO4. Removal of the solvent in vacuo
provided 3b as a yellow oil (0.36 g, 53% yield): TLC (Rf ) 0.5;
We have used solution-phase combinatorial library
synthesis techniques to discover a novel class of antibac-
terial compounds. The use of an oxyamino-containing
scaffold allowed control of product distribution obtained
by reaction with both acylating and alkylating agents.
Moreover, library SAR study was conducted by reductive
cleavage of the oxyamine bond of the scaffold. Several
single compounds and SAR compounds were synthesized
on the basis of the initial antibacterial screening results
of the library mixtures and were shown to have interest-
ing antibacterial activities.
1
20% EtOAc/hexanes); H NMR (CDCl3) δ 7.35 (m, 10H), 3.85
(s, 4H), 3.18 (s, 3H); 13C NMR (CDCl3) δ 137.8, 129.5, 128.1,
Exp er im en ta l Section
(12) Willy, W. E.; McKean, D. R.; Garcia, B. A. Bull. Chem. Soc.
J pn. 1976, 49, 1989.
Gen er a l. All commercial reagents and solvents were used
as received from their respective suppliers with the following
(13) Still, W. C.; Kahn, M.; Mitra, A. J . Org. Chem. 1978, 43, 2923.
(14) National Committee for Clinical Laboratory Standards. Methods
for Dilution Antimicrobial Susceptibility Tests for Bacterial that Grow
Aerobically, 1993, MCCLS Document M7-A3, Vol. 13, Villanova, PA.
(15) Sampson, B. A.; Misra, R.; Benson, S. A. Genetics 1989, 122,
491.
(11) (a) Bruice, T. C.; Donzel, A.; Huffman, R. W.; Butler, A. R. J .
Am. Chem. Soc. 1967, 89, 2106. (b) Gregory, M. J .; Bruice, T. C. J .
Am. Chem. Soc. 1967, 89, 4400.

1850 J . Org. Chem., Vol. 63, No. 6, 1998
Kung et al.
127.2, 62.3, 61.0; HRMS (FAB) m/z 227.1310 (M + H)+ (C15H17
-
activated carbon (10%, 1.0 g), and MeOH/HOAc (100 mL, v/v,
95:5) was transferred to a 250 mL Parr hydrogenation flask.
The flask was purged and filled with H2 three times and then
left under H2 atmosphere at 55 psi with shaking for 4 h. The
reaction mixture was filtered through a bed of Celite and the
solvent was evaporated in vacuo to give a yellowish oil. The
oil residue was purified by flash column chromatography using
MeOH/CH2Cl2 as the eluent to afford 2.5 g (68%) of the title
compound as a white solid: mp 94-95 °C; TLC (Rf ) 0.38;
50% EtOAc/MeOH); 1H NMR (DMSO-d6) δ 7.87 (m, 4H), 6.20
(br, 2H), 3.72 (t, 2H, J ) 6.3), 3.44 (t, 2H, J ) 6.4), 2.84 (t, 2H,
J ) 6.3), 2.66 (t, 2H, J ) 6.8), 1.83 (s, 3H), 1.57 (t, 2H, J )
6.6); 13C NMR (DMSO-d6) δ 172.8, 168.0, 134.3, 131.8, 122.9,
59.3, 46.6, 45.8, 36.8, 31.9, 21.9; HRMS (FAB) m/z 249.1247
(M + H)+ (C13H16N2O3 requires 249.1289).
NO requires 227.1395).
2-(Me t h oxym e t h yla m in o)-N -(3-n it r op h e n yl)a ce t a -
m id e (3). 2-Bromo-N-(3-nitrophenyl)acetamide (1.17 g, 4.48
mmol) was dissolved in a 3/2 mixture of THF/DMF (10 mL) at
ambient temperature, and N,O-dimethylhydroxylamine hy-
drochloride (0.22 g, 2.24 mmol) and diisopropylethylamine
(0.75 mL, 8.96 mmol) were added sequentially. After stirring
at ambient temperature for 12 h, a freshly prepared solution
of 2-mercapto-1-ethanesulfonic acid sodium salt (1.52 g, 9.25
mmol) and potassium carbonate (1.23 g, 8.89 mmol) in water
(10 mL) was added. After stirring of the biphasic reaction
mixture for 30 min, EtOAc (50 mL) was added and the mixture
was agitated. The organic layer was separated, washed with
water (2 × 10 mL) and brine (1 × 10 mL), and dried over
MgSO4. Removal of the solvent in vacuo provided 4 as a solid
(0.54 g, 76%): Rf ) 0.5 (25% EtOAc in hexanes); 1H NMR
(CDCl3) δ 8.90 (br, 1H), 8.0 (m, 2H), 7.51 (m, 1H), 3.63 (s, 3H),
3.50 (s, 2H), 2.75 (s, 3H); 13C NMR (CDCl3) δ 167.8, 148.7,
138.7, 130.0, 125.2, 118.9, 114.2, 64.2, 59.8, 44.2; HRMS (FAB)
m/z 240.0989 (M + H)+ (C10H13N3O4 requires 240.0984).
N-Ben zot h ia zol-2-yl-2-(m et h oxym et h yla m in o)a cet a -
m id e (4). 2-Bromo-N-(2-benzothiazolyl)acetamide (2.84 g,
10.5 mmol) was dissolved in a 3/2 mixture of THF/DMF (20
mL) at ambient temperature, and N,O-dimethylhydroxylamine
hydrochloride (509 mg, 5.21 mmol) and diisopropylethylamine
(2.0 mL, 12 mmol) were added sequentially. After stirring at
ambient temperature for 12 h, a freshly prepared solution of
2-mercapto-1-ethanesulfonic acid sodium salt (1.71 g, 10.4
mmol) and potassium carbonate (1.44 g, 10.4 mmol) in water
(10 mL) was added. After stirring of the biphasic reaction
mixture for 30 min, EtOAc (50 mL) was added and the mixture
was agitated. The organic layer was separated, washed with
water (2 × 10 mL) and brine (1 × 10 mL), and dried over
MgSO4. Removal of the solvent in vacuo provided 4 as a solid
(0.66 g, 51%): Rf ) 0.2 (25% EtOAc in hexanes); 1H NMR
(CDCl3) δ 10.11 (br s, 1H), 7.82 (m, 2H), 7.41 (m, 2H), 3.62 (s,
3H), 3.60 (s, 2H), 2.73 (s, 2H); 13C NMR (CDCl3) δ 167.7, 157.0,
148.4, 132.3, 126.2, 124.0, 121.4, 121.0, 63.3, 59.8, 44.2.
3-Ben zyla m in op r op a n -1-ol (5). 3-Amino-1-propanol (7.2
mL, 94.2 mmol) was added dropwise to a solution of benzal-
dehyde (10 g, 94.2 mmol) and trimethyl orthoformate (15.5 mL,
141 mmol) in MeOH (300 mL) at room temperature. The
reaction was stirred at room temperature for 5 h and then was
cooled in an ice bath. Sodium borohydride (3.6 g, 94.2 mmol)
was added in two portions, and when gas evolution stopped,
the solvent was then evaporated. The resulting residue was
partitioned between EtOAc (300 mL) and H2O (300 mL). The
aqueous layer was extracted with more EtOAc (2 × 75 mL).
The combined organic layers were washed with brine, dried
(Na2SO4), filtered, and evaporated to give the title compound
(14.4 g, 93%) as pale yellow, oily residue: TLC (Rf ) 0.14; 70%
EtOAc/hexanes); 1H NMR (CDCl3) δ 7.27 (m, 5H), 3.80 (s, 2H),
3.60 (t, 2H, J ) 5.6), 2.72 (t, 2H, J ) 6.2), 1.60 (m, 2H); 13C
NMR (CDCl3) δ 139.2, 128.5, 127.7, 127.2, 62.6, 53.7, 48.2, 31.2.
2-{2-[Ben zyl(3-h yd r oxyp r op yl)a m in o]eth yl}isoin d ole-
1,3-d ion e (6) N-(2-Bromoethyl)phthalimide (9.4 g, 37 mmol),
potassium carbonate (1.5 g, 11 mmol), and potassium iodide
(91.3 mg, 0.55 mmol) were added sequentially to a solution of
5 (6.0 g, 36.8 mmol) in DMF (300 mL). The resulting mixture
was maintained at 65 °C for 10 h. The reaction mixture was
evaporated in vacuo and partitioned between EtOAc (300 mL)
and H2O (300 mL). The aqueous layer was extracted with
more EtOAc (3 × 50 mL). The combined organic layers were
dried (Na2SO4), filtered, and evaporated to give a residue.
Purification of the residue by flash column chromatography
(gradient elution, 10% f 40% EtOAc/hexanes) provided 6 (7.0
g, 56%): TLC (Rf ) 0.68; 100% EtOAc); 1H NMR (CDCl3) δ
7.71 (m, 4H), 7.15 (m, 5H), 3.80 (t, 2H, J ) 6.1), 3.63 (t, 2H, J
) 5.5), 3.60 (s, 2H), 2.72 (q, 4H, J ) 6.3), 1.70 (m, 2H); 13C
NMR (CDCl3) δ 168.4, 138.3, 133.9, 129.2, 128.3, 127.2, 123.2,
62.1, 58.3, 52.5, 51.8, 35.8, 28.7; HRMS (FAB) m/z 339.1693
(M + H)+ (C20H22N2O3 requires 339.1709).
[2-(1,3-Dioxo-1,3-d ih yd r oisoin d ol-2-yl)eth yl](3-h yd r ox-
yp r op yl)ca r ba m ic Acid ter t-Bu tyl Ester (8). Di-tert-butyl
dicarbonate (3.6 g, 16.3 mmol) was added to a solution of 7
(2.5 g, 8.1 mmol) and triethylamine (5.6 mL, 40.5 mmol) in
CH2Cl2 (40 mL). The reaction was stirred at room temperature
for 4 h. The reaction mixture was washed with H2O (3 × 20
mL) and brine (1 × 10 mL) and dried over Na2SO4. Removal
of the solvent in vacuo provided a residue which was purified
by flash column chromatography using EtOAc/hexanes as the
eluent to afford 2.4 g (81%) of the title compound as a colorless
1
oil: TLC (Rf ) 0.72; 95% EtOAc/MeOH); H NMR (CDCl3) δ
7.80 (m, 2H), 7.73 (m, 2H), 3.84 (t, 2H, J ) 6.0), 3.65 (br, 1H),
3.42 (m, 6H), 1.19 (m, 2H), 1.29 (s, 9H); 13C NMR (CDCl3) δ
167.9, 156.5, 134.0, 131.9, 123.2, 80.4, 58.2, 42.4, 35.6, 30.2,
27.9; HRMS (FAB) m/z 371.1598 (M + Na)+ (C18H24N2O5
requires 371.1583).
[2-(1,3-Dioxo-1,3-d ih yd r oisoin d ol-2-yl)eth yl][3-(1,3-d i-
oxo-1,3-d ih yd r oisoin d ol-2-yloxy)p r op yl]ca r ba m ic Acid
ter t-Bu tyl Ester (9). N-Hydroxyphthalimide (0.60 g, 3.7
mmol)) and triphenylphosphine (0.94 g, 3.6 mmol) were added
to a solution of 8 (1.2 g, 3.3 mmol) in anhydrous THF (30 mL).
The reaction mixture was cooled in an ice bath and diethyl
azodicarboxylate (0.6 mL, 4.0 mmol) was added dropwise. The
reaction was warmed to room temperature and maintained
at that temperature for 12 h. The reaction mixture was
concentrated in vacuo and Et2O (100 mL) was added. The title
compound was precipitated and filtered to afford 1.2 g (75%)
as a white solid: mp 171-173 °C; 1H NMR (CDCl3) δ 7.81 (m,
4H), 4.22 (t, 2H, J ) 6.2), 3.89 (t, 2H, J ) 5.9), 3.63 (t, 2H, J
) 4.9), 3.48 (t, 2H, J ) 5.9), 2.02 (m, 2H), 1.20 (s, 9H); 13C
NMR (CDCl3) δ 168.1, 136.7, 155.6, 123.5, 134.0, 132.3, 129.0,
123.5, 123.3, 79.8, 76.1, 45.6, 43.8, 36.2, 28.1; HRMS (FAB)
m/z 494.1912 (M + H)+ (C26H27N3O7 requires 494.1927). Anal.
Calcd for C26H27N3O7: C, 63.28; H, 5.51; N, 8.51. Found: C,
63.08; H, 5.52; N, 8.63.
(2-Am in oeth yl)(3-a m in ooxyp r op yl)ca r ba m ic Acid ter t-
Bu tyl Ester (1). Anhydrous hydrazine (0.16 mL, 5 mmol) was
added to a solution of 9 (0.5 g, 1.0 mmol) in absolute EtOH
(15 mL). The mixture was stirred at 45 °C for 2 h. The
reaction mixture was concentrated in vacuo to give a semi-
crystalline slurry. The slurry was taken into CH2Cl2 (25 mL)
and the precipitate of phthalalhydrazide was filtered off and
rinsed with CH2Cl2 (2 × 2 mL). The filtrate was concentrated
in vacuo to give a pale yellow oily residue (0.23 g, 98%): TLC
1
(Rf ) 0.18; 100% MeOH); H NMR (CDCl3) δ 3.61 (t, 2H, J )
6.3), 3.20 (m, 4H), 2.76 (t, 2H, J ) 6.7), 1.76 (t, 2H, J ) 7.4),
1.40 (s, 9H); 13C NMR (CDCl3) δ 154.7, 79.6, 74.2, 55.3, 52.9,
43.5, 28.4, 25.8; HRMS (FAB) m/z 234.1818 (M + H)+
(C10H23N3O3 requires 234.1818). Anal. Calcd for C12H25
-
N3O3‚1.15H2O‚0.5CH3OH: C, 48.97; H, 9.76; N, 14.90.
Found: C, 48.94; H, 9.37; N, 15.26.
P r ep a r a tion of Libr a r y 10. A solution of benzyl bromide
(692 µL, 4.8 equiv), R-bromo-m-xylene (785 µL, 4.8 equiv), and
R-bromo-R′,R′,R′-trifluoro-m-xylene (888 µL, 4.8 equiv) in THF
(40 mL) was added dropwise to a stirred mixture of 1 (0.28 g,
1.21 mmol) in THF (10 mL) at room temperature. N,N-
Diisopropylethylamine (1.7 mL, 9.68 mmol) was added and the
resulting reaction mixture was refluxed for 12 h. The reaction
mixture was then poured into a mixture of 3-mercapto-1-
propanesulfonic acid sodium salt (2.85 g, 16 mmol) and
2-[2-(3-H yd r oxyp r op yla m in o)et h yl]isoin d ole-1,3-d i-
on e (7). A mixture of 6 (4.6 g, 11.9 mmol), palladium on

Linear Oxyamine Combinatorial Libraries
J . Org. Chem., Vol. 63, No. 6, 1998 1851
potassium carbonate (4.5 g, 32 mmol) in MeOH/H2O (100 mL,
v/v, 50:50). The mixture was stirred at room temperature for
2 h and concentrated in vacuo. The resultant residue was
partitioned between Et2O (40 mL) and H2O (40 mL), and the
aqueous layer was extracted with more Et2O (2 × 20 mL). The
combined organic layers were dried (Na2SO4), filtered, and
concentrated in vacuo to give the title library (0.94 g, 99% mass
recovery). The resultant pale yellow oily residue was identified
by ES(ESI) m/z 594, 608, 623, 636, 650, 662, 676, 690, 704,
730, 744, 758, 798, 812, 866 (M + H)+.
P r ep a r a tion of Libr a r y 11. A solution of HCl in EtOH
(4 M, 26 mL) was added to library 10 (1.21 mmol) at room
temperature. The resulting solution was stirred at room
temperature for 12 h. The volatiles were evaporated in vacuo,
and the residue was dissolved in H2O (30 mL) and basicified
with solid NaOH at 0 °C. The aqueous layer was extracted
with EtOAc (2 × 20 mL). The combined organic layers were
dried (Na2SO4), filtered, and evaporated to give the title library
as a pale yellow, oily residue (0.81 g, 1.34 mmol, quantitative
mass recovery). The resultant pale yellow, oily residue was
identified by ES(ESI) m/z 494, 508, 522, 536, 550, 562, 576,
590, 604, 630, 644, 658, 698, 712, 766 (M + H)+.
Gen er a l P r oced u r e for th e P r ep a r a tion of Libr a r ies
12-14. A mixture of library 11, a specific benzyl bromide (2
equiv), and N,N-diisopropylethylamine (2 equiv) in 5 mL of
THF was stirred at room temperature for 12 h. The reaction
mixture was then poured into a mixture of 3-mercapto-1-
propanesulfonic acid sodium salt (0.05 g, 0.27 mmol) and
potassium carbonate (0.1 g, 0.6 mmol) in MeOH/H2O (10 mL,
v/v, 50:50). The mixture was stirred at room temperature for
2 h and concentrated in vacuo. The resultant residue was
partitioned between Et2O (10 mL) and H2O (10 mL), and the
aqueous layer was extracted with more Et2O (2 × 5 mL). The
combined organic layers were dried (Na2SO4), filtered, and
concentrated in vacuo to give the desired library.
(2-Dib en zyla m in oet h yl)[3-(N,N-d ib en zyla m in ooxy)-
p r op yl]ca r ba m ic a cid ter t-bu tyl ester (16): flash column
chromatography (gradient elution, 0% f 20% EtOAc/hexanes);
pale yellow oil, yield 1.06 g (50%); TLC (Rf ) 0.5; 20% EtOAc/
MeOH); 13C NMR (CDCl3) δ 155.2, 139.6, 137.8, 129.6, 129.2,
128.7, 127.6, 127.2, 126.8, 78.9, 70.7, 62.5, 58.6, 51.9, 45.3, 44.5,
28.4, 27.4; HRMS (FAB) m/z 594.3712 (M + H)+ (C38H47N3O3
requires 594.3696).
{2-[Bis-(3-m et h ylb en zyl)a m in o]et h yl}{3-[N,N-b is-(3-
m eth ylben zyl)a m in ooxy]p r op yl}ca r ba m ic Acid ter t-Bu -
tylEster (17): flash column chromatography (gradient elu-
tion, 0% f 10% EtOAc/hexanes); pale yellow oil, yield 1.25 g
(60%); TLC (Rf ) 0.7; 30% EtOAc/MeOH); 13C NMR (CDCl3) δ
155.2, 139.5, 137.7, 137.5, 130.3, 129.4, 127.9, 127.5, 126.6,
125.8, 78.9, 70.7, 62.5, 58.6, 52.0, 45.3, 44.5, 28.3, 27.0, 21.3;
HRMS (FAB) m/z 650.4350 (M + H)+ (C42H55N3O3 requires
650.4322).
{2-[Bis(3-tr iflu or om eth ylben zyl)a m in o]eth yl}{3-[N,N-
b is (3-t r iflu o r o m e t h y lb e n zy l)a m in o o x y ]p r o p y l}c a r -
ba m ic a cid ter t-bu tyl ester (18): pale yellow oil, yield 0.2
g (81%); TLC (Rf ) 0.5; 30% EtOAc/MeOH); HRMS (FAB) m/z
998.2205 (M + Cs)+ (C42H43N3O3F12 requires 998.2167).
{2-[Bis(3-m et h oxyb en zyl)a m in o]et h yl}{3-[N,N-b is(3-
m eth oxyben zyl)a m in ooxy]p r op yl}ca r ba m ic a cid ter t-
bu tyl ester (19): flash column chromatography (gradient
elution, 0% f 30% EtOAc/hexanes); pale yellow oil, yield 0.59
g (67.2%); TLC (Rf ) 0.5; 30% EtOAc/hexanes); 13C NMR
(CDCl3) δ 159.6, 159.5, 155.3, 141.3, 139.4, 129.0, 121.9, 120.9,
115.1, 114.1, 112.6, 112.3, 79.0, 70.7, 62.4, 58.5, 55.1, 52.0, 51.9,
45.2, 44.6, 28.3; HRMS (FAB) m/z 714.4145 (M + H)+
(C42H55N3O7 requires 714.4118).
{2-[Bis(2,6-d ich lor op yr id in e-4-m eth yl)a m in o]eth yl}{3-
[N ,N -b is (2,6-d ic h lo r o p y r id in e -4-m e t h y l)a m in o o x y ]-
p r op yl}ca r ba m ic a cid ter t-bu tyl ester (20): flash column
chromatography (gradient elution, 0% f 30% EtOAc/hexanes);
red oil, yield 0.15 g (83.5%); TLC (Rf ) 0.3; 30% EtOAc/
hexanes); 13C NMR (CDCl3) δ 154.1, 151.4, 150.8, 123.4, 122.6,
80.2, 71.4, 60.8, 56.6, 52.4, 44.2, 42.6, 28.5, 27.4; HRMS (FAB)
m/z 1006.2214 (M + Cs)+ (C34H35N7O3Cl8 requires 1006.2271).
{2-[Bis(3,4-d ich lor ob en zyl)a m in o]et h yl}{3-[N,N-b is-
(3,4-dich lor oben zyl)am in ooxy]pr opyl}car bam ic acid ter t-
bu tyl ester (21): colorless oil, yield 0.13 g (74%); TLC (Rf )
0.5; 30% EtOAc/hexanes); HRMS (FAB) m/z 1001.9561 (M +
Cs)+ (C38H39N3O3Cl8 requires 1001.9503).
Libr a r y 12: pale yellow oil, yield 54 mg (quantitative yield);
ES(ESI) m/z 584, 598, 612, 627, 640, 652, 666, 680, 694, 720,
734, 748, 788, 802, 856 (M + H)+.
Libr a r y 13: pale yellow oil, yield 43 mg (91%); ES(ESI)
m/z 598, 612, 627, 641, 655, 666, 680, 694, 708, 734, 748, 762,
802, 816, 870 (M + H)+.
Libr a r y 14: pale yellow oil, yield 51 mg (76%); ES(ESI)
m/z 652, 666, 680, 694, 710, 720, 734, 748, 762, 788, 802, 816,
856, 870, 924 (M + H)+.
P r ep a r a tion of Libr a r y 15. A solution of BH3 in THF (1
M, 6 mL) was added to library 11 (0.04 mmol) in THF (10 mL)
at room temperature. The resulting solution was refluxed for
12 h and then cooled to room temperature and to it was added
a solution of HCl in H2O (6 M, 50 mL). The volatiles were
evaporated in vacuo and the aqueous solution was basicified
with solid NaOH at 0 °C. The aqueous layer was extracted
with EtOAc (2 × 20 mL). The combined organic layers were
dried (Na2SO4), filtered, and evaporated to give a pale yellow,
oily residue. Purification of the residue by flash column
chromatography (gradient elution, 5% f 20% MeOH/CH2Cl2,
then 20% MeOH/CH2Cl2, 1% H2O) provided 15 (5 mg, 0.014
mmol, 35% mass recovery). The resultant colorless oily residue
was identified by ES(ESI) [m/z 299, 313, 327, 367, 381, 435
(M + H)+].
Gen er a l P r oced u r e for th e P r ep a r a tion of Com p ou n d s
16-22. A mixture of compound 1, a specific benzyl bromide
(6 equiv), and N,N-diisopropylethylamine (12 equiv) in THF
(50 mL) was refluxed for 12 h. The reaction mixture was then
poured into a mixture of 3-mercapto-1-propanesulfonic acid
sodium salt (1 equiv to the specific benzyl bromide) and
potassium carbonate (2 equiv to 3-mercapto-1-propanesulfonic
acid sodium salt) in MeOH/H2O (100 mL, v/v, 50:50). The
mixture was stirred at room temperature for 2 h and concen-
trated in vacuo. The resultant residue was partitioned
between Et2O (100 mL) and H2O (50 mL), and the aqueous
layer was extracted with more Et2O (2 × 50 mL). The
combined organic layers were dried (Na2SO4), filtered, and
concentrated in vacuo to give an oily residue. The oily residue
was either used directly for the next reaction or purified by
flash column chromatography.
{2-[Bis-(2-m e t h ylb e n zyl)a m in o]e t h yl}{3-[N ,N -b is(2-
m eth ylben zyl)a m in ooxy]p r op yl}ca r ba m ic a cid ter t-bu -
tyl ester (22): flash column chromatography (gradient elu-
tion, 0% f 20% EtOAc/hexanes); red oil, yield 0.16 g (62%);
TLC (Rf ) 0.7; 30% EtOAc/hexanes); 13C NMR (CDCl3) δ 155.1,
137.6, 137.2, 135.7, 131.2, 131.1, 130.2, 130.0, 129.8, 127.7,
127.4, 126.9, 125.4, 78.9, 70.7, 61.1, 57.3, 52.4, 44.4, 28.3, 27.5,
19.1; HRMS (FAB) m/z 650.4303 (M + H)+ (C42H55N3O3
requires 650.4322).
Gen er a l P r oced u r e for th e P r ep a r a tion of Com p ou n d s
23-29 A solution of HCl in EtOH (4 M, 50 mL) was added to
a specific compound (3 mmol) at room temperature. The
resulting solution was stirred at room temperature for 12 h.
The volatiles were evaporated in vacuo and the residue was
dissolved in H2O (30 mL) and basicified with solid NaOH at 0
°C. The aqueous layer was extracted with EtOAc (2 × 40 mL).
The combined organic layers were dried (Na2SO4), filtered, and
evaporated to give the title compound as an oily residue. The
oily residue was either used directly or purified by flash
column chromatography for the antimicrobial screening.
N,N-Diben zyl-O-[3-(2-d iben zyla m in oeth yla m in o)p r o-
p yl]h yd r oxyla m in e (23): flash column chromatography
(gradient elution, 0% f 5% MeOH/CH2Cl2); pale yellow oil,
yield 0.62 g (92%); TLC (Rf ) 0.3; 5% MeOH/CH2Cl2); 1H NMR
(CDCl3) δ 7.12 (m, 16H), 3.79 (s, 4H), 3.51 (s, 4H), 3.31 (t, 2H,
J ) 6.2), 2.53 (s, 4H), 2.15 (t, 2H, J ) 7.2), 1.34 (m, 2H); 13C
NMR (CDCl3) δ 139.6, 137.9, 129.6, 128.8, 128.2, 128.1, 127.2,
126.9, 71.4, 62.6, 58.7, 53.5, 47.4, 46.8, 29.2; HRMS (FAB) m/z
494.3178 (M + H)+ (C33H39N3O requires 494.3171). Anal.
Calcd for C33H39N3O‚1/4H2O: C, 79.56; H, 7.99; N, 8.43.
Found: C, 79.80; H, 7.89; N, 8.51.

1852 J . Org. Chem., Vol. 63, No. 6, 1998
Kung et al.
O-(3-{2-[Bis(3-m eth ylben zyl)am in o]eth ylam in o}pr opyl)-
N,N-bis(3-m eth ylben zyl)h yd r oxyla m in e (24): flash col-
umn chromatography (gradient elution, 0% f 5% MeOH/
CH2Cl2); pale yellow oil, yield 0.78 g (84.3%); TLC (Rf ) 0.4;
5% MeOH/CH2Cl2); 1H NMR (CDCl3) δ 7.32 (m, 20H), 3.82 (s,
4H), 3.54 (s, 4H), 3.28 (t, 2H, J ) 6.3), 2.52 (s, 4H), 2.33 (s,
12H), 2.18 (t, 2H, J ) 7.3), 1.70 (br, 1H), 1.39 (m, 2H); 13C
NMR (CDCl3) δ 139.2, 137.7, 137.5, 130.3, 129.6, 128.1, 127.9,
127.7, 127.6, 126.6, 125.9, 70.9, 62.6, 58.8, 52.6, 46.8, 46.5, 28.3,
21.3; HRMS (FAB) m/z 550.3812 (M + H)+ (C37H47N3O requires
550.3797). Anal. Calcd for C33H39N3O‚1/2H2O: C, 79.53; H, 8.66;
N, 7.52. Found: C, 79.45; H, 8.56; N, 7.41.
CH2Cl2); pale yellow oil, yield 0.13 g (74.5%); TLC (Rf ) 0.5;
1
10% MeOH/CH2Cl2); H NMR (CDCl3) δ 7.25-7.11 (m, 16H),
3.82 (s, 4H), 3.51 (s, 4H), 3.05 (t, 2H, J ) 6.3), 2.50 (s, 4H),
2.32(s, 6H), 2.23 (s, 6H), 2.03 (t, 2H, J ) 7.3), 1.70 (br, 1H),
1.19 (m, 2H); 13C NMR (CDCl3) δ 137.6, 137.2, 137.1, 135.7,
131.1, 130.1, 130.0, 127.6, 127.4, 126.7, 126.9, 125.5, 71.1, 61.1,
57.5, 53.8, 47.3, 46.6, 28.9, 19.1; HRMS (FAB) m/z 550.3785
(M + H)+ (C37H47N3O requires 550.3797). Anal. Calcd for
C
37H47N3O‚1/4H2O‚1HCl: C, 75.23; H, 8.28; N, 7.11. Found:
C, 75.10; H, 8.11; N, 7.06.
P r ep a r a tion of Libr a r y 30. Benzyl bromide (0.52 mL, 3
equiv) was added dropwise to a stirred solution of 1 (0.33 g,
1.44 mmol) in THF (30 mL) at room temperature. N,N-
Diisopropylethylamine (2.5 mL, 14.4 mmol) was added and the
reaction mixture was stirred at room temperature for 12 h.
Benzoyl chloride (0.67 mL, 4 equiv) was added to the reaction
under argon. The resulting mixture was stirred at room
temperature for 12 h and was then poured into a solution of
3-mercapto-1-propanesulfonic acid sodium salt (2.0 g, 11.1
mmol) and potassium carbonate (3.1 g, 22.2 mmol) in MeOH/
H2O (100 mL, v/v, 50:50). The mixture was stirred at room
temperature for 2 h and concentrated in vacuo. The resultant
residue was partitioned between Et2O (40 mL) and H2O (40
mL), and the aqueous layer was extracted with more Et2O (2
× 20 mL). The combined organic layers were dried (Na2SO4),
filtered, and concentrated in vacuo to give the title library (0.68
g, 90% mass recovery). The resultant yellow oily residue was
analyzed using ESI(ES) in both negative and positive modes
yielding peaks of 516 and 530 amu. The structures of the two
compounds were verified using MS/MS in the positive mode.
O-(3-{2-[Bis(3-t r iflu or om e t h ylb e n zyl)a m in o]e t h yl-
a m in o}p r op yl)-N,N-bis(3-tr iflu or om eth ylben zyl)h yd r ox-
yla m in e (25): pale yellow oil, yield 0.16 g (94%); 1H NMR
(CDCl3) δ 7.46 (m, 16H), 3.87 (s, 4H), 3.60 (s, 4H), 3.24 (t, 2H,
J ) 6.2), 2.65 (m, 2), 2.55 (s, 4H), 2.16 (t, 2H, J ) 7.2); HRMS
(FAB) m/z 766.2639 (M + H)+ (C37H35N3OF12 requires 766.2667).
O-(3-{2-[Bis(3-m e t h oxyb e n zyl)a m in o]e t h yla m in o}-
p r op yl)-N,N-bis(3-m eth oxyben zyl)h yd r oxyla m in e (26):
flash column chromatography (gradient elution, 0% f 10%
MeOH/CH2Cl2); pale yellow oil, yield 0.41 g (81.6%); TLC (Rf
1
) 0.5; 10% MeOH/CH2Cl2); H NMR (CDCl3) δ 7.19 (m, 4H),
6.89-6.76 (m, 12H), 3.79 (s, 4H), 3.76 (s, 12H), 3.52 (s, 4H),
3.37 (t, 2H, J ) 6.3), 2.54 (s, 4H), 2.20 (t, 2H, J ) 7.3), 1.70
(br, 1H), 1.39 (m, 2H); 13C NMR (CDCl3) δ 159.5, 159.3, 141.2,
139.3, 129.0, 128.9, 121.8, 120.9, 115.0, 114.3, 112.5, 112.1,
71.3, 62.3, 58.6, 55.0, 53.5, 47.3, 46.8, 29.1; HRMS (FAB) m/z
614.3576 (M + H)+ (C37H47N3O5 requires 614.3594). Anal.
Calcd for C37H47N3O5‚1/4HCl: C, 71.34; H, 7.65; N, 6.75.
Found: C, 71.29; H, 7.64; N, 6.56.
Both the 516 and 530 amu peaks produced a fragment ion at
+
O-(3-{2-[Bis(2,6-d ich lor op yr id in e -4-m e t h yl)a m in o]-
eth yla m in o}p r op yl)-N,N-bis(2,6-d ich lor op yr id in e-4-m e-
th yl)h yd r oxyla m in e (27): flash column chromatography
(gradient elution, 0% f 5% MeOH/CH2Cl2); brown yellow oil,
yield 0.78 g (63.8%); TLC (Rf ) 0.3; 5% MeOH/CH2Cl2); 1H
NMR (CDCl3) δ 7.29 (s, 8H), 3.82 (s, 4H), 3.60 (s, 4H), 3.28 (t,
2H, J ) 5.8), 2.67 (m, 4H), 2.27 (t, 2H, J ) 7.3), 1.70 (br, 1H),
1.54 (m, 2H); 13C NMR (CDCl3) δ 153.7, 151.4, 151.0, 150.8,
123.4, 122.5, 71.4, 60.8, 57.3, 46.6, 46.3, 27.9. Anal. Calcd for
136.2 amu which corresponds to the mass of ONHCOC6H5
.
P r ep a r a tion of Libr a r y 31. A solution of HCl in EtOH
(4 M, 26 mL) was added to library 30 (1.3 mmol) at room
temperature. The resulting solution was stirred at room
temperature for 12 h. The volatiles were evaporated in vacuo
to give the title library as a brown yellow oily residue
(quantitative mass recovery). The oily residue was analyzed
using ESI(ES) m/z 417, 431 (M - H)-.
C
29H27N7OCl8‚3/4H2O‚1/2HCl‚1/2CH3OH: C, 43.98; H, 3.75; N,
Ack n ow led gm en t. The authors thank Mr. Michael
Greig for taking the MS/MS spectra and Dr. J ackie
Wyatt, Ms. Lisa Risen, and Ms. Laura Wilson-Lingardo
for conducting the antimicrobial screenings.
11.77. Found: C, 44.05; H, 3.34; N, 11.81.
O-(3-{2-[Bis(3,4-d ich lor ob en zyl)a m in o]et h yla m in o}-
p r o p y l)-N ,N -b is (3,4-d ic h lo r o b e n zy l)h y d r o x y la m in e
(28): flash column chromatography (gradient elution, 0% f
5% MeOH/CH2Cl2); colorless oil, yield 0.09 g (88.5%); TLC (Rf
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra of 2b, 28; 1H NMR spectra of 2a , 4, 6, 7, 8, 18, 21, 25;
13C NMR spectra of 3, 5, 16, 17, 19, 20, 22; high-resolution
mass spectra of 18, 20, 21, 25; ESI spectra of libraries 10, 11,
12, 13, 14, 15, 30, 31, and MS/MS spectra of 30 (38 pages).
This material is contained in libraries on microfiche, im-
mediately follows this article in the microfilm version of the
journal, and can be ordered from the ACS; see any masthead
page for ordering information.
1
) 0.3; 5% MeOH/CH2Cl2); H NMR (CDCl3) δ 7.36-7.15 (m,
12H), 3.75 (s, 4H), 3.49 (s, 4H), 3.30 (t, 2H, J ) 6.1), 2.52 (m,
4H), 2.20 (t, 2H, J ) 7.3), 1.34 (m, 2H); 13C NMR (CDCl3) δ
139.6, 137.6, 132.5, 132.2, 131.5, 131.1, 130.5, 130.3, 130.2,
128.9, 127.9, 127.7, 71.6, 61.4, 57.7, 53.6, 47.3, 47.0, 29.1;
HRMS (FAB) m/z 768.0056 (M + H)+ (C33H31N3OCl8 requires
768.0022).
O-(3-{2-[Bis(2-m eth ylben zyl)am in o]eth ylam in o}pr opyl)-
N,N-bis(2-m eth ylben zyl)h yd r oxyla m in e (29): flash col-
umn chromatography (gradient elution, 0% f 5% MeOH/
J O971655U