Direct access to terpyridine-containing polyazamacrocycles as photosensitizing ligands for Eu(III) luminescence in aqueous media

Article abstract of DOI:10.1021/jo0480242

(Chemical Equation Presented) The synthesis of new 18-membered hexaazamacrocycles containing a functionalized 2,2′:6′,2″- terpyridine moiety as part of the cyclic backbone and three acetate pendant arms is described. The reported synthetic procedure is ba

Full text of DOI:10.1021/jo0480242

Direct Access to Terpyridine-Containing Polyazamacrocycles as
Photosensitizing Ligands for Eu(III) Luminescence in Aqueous
Media
Chantal Galaup,* Jean-Marc Couchet, S e´ bastien Bedel, Pierre Tisn e` s, and Claude Picard*
Laboratoire de Synth e` se et Physicochimie de Mol e´ cules d’Int e´ r eˆ t Biologique, CNRS UMR 5068,
Universit e´ Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 04, France
galaup@chimie.ups-tlse.fr; picard@chimie.ups-tlse.fr
Received November 5, 2004
The synthesis of new 18-membered hexaazamacrocycles containing a functionalized 2,2′:6′,2′′-
terpyridine moiety as part of the cyclic backbone and three acetate pendant arms is described. The
reported synthetic procedure is based on the use of an efficient metal template ion effect which
controls the macrocyclization step. This procedure is compatible with some functional groups present
in the macrocyclic structure. The photophysical properties of the Eu(III) complexes derived from
these ligands were examined in aqueous solutions. Their luminescence lifetimes (τ ≈ 1 ms) and
quantum yields (13% < Φ < 18%) on one hand, their high kinetic inertness on the other hand, and
the presence of additional functionality allowing their covalent conjugation to biomolecules seriously
nominate these complexes as very promising candidates for luminescent labeling of biological
materials.
Introduction
luminescent labels in hybridization, enzyme or receptor
assays, cell sorting, bioactive ion detection, the lumines-
Fluorometry is a very powerful technology and one of
the fastest growing and most widespread analytical tools
in biosciences. Consequently, the design of fluorophores
which are suitable for direct determination of analytes
in complex biological matrixes is a topical subject and
an area of active investigation. In this respect, Ln(III)
organocomplexes (Ln ) Eu and Tb especially) offer a
number of advantageous features as fluorescent labels
over conventional organic dyes, including (i) long emis-
sion lifetimes (millisecond range) under ambient condi-
tions, the signal can thus be easily distinguished from
light scattering and short-lived (nanosecond range) fluo-
rescence background, (ii) no self-quenching, allowing
enhancement of the detection sensitivity by multilabeling
of biomolecules, and (iii) excellent solubility in aqueous
cence resonance energy transfer (LRET) technique, and
optical microscopy has also been reported.4
To design an efficient luminescent Ln(III) edifice, it is
well established that the ligand should possess a strong
binding domain which ensures a high kinetic stability
with respect to metal ion dissociation and a chromophoric
domain which collects the excitation light and channels
4a
it to the lanthanide ion. Moreover, it must have a high
denticity to avert direct coordination of water molecules,
which leads to radiationless energy transfer to the
aqueous solvent shell. To avoid ligand exchange processes
and generate high kinetic inertness of Ln(III) complexes
in aqueous solutions and biological media, the same basic
ligand systems which have been developed for the
elaboration of Gd(III) contrast agents for magnetic
1
,2
solvents. Several europium-complex-based detection
systems for time-resolved fluoroimmunoassays are avail-
5
resonance imaging were exploited for use in luminescent
Ln(III) bioprobe research. A survey of the literature
3
able for routine biomedical diagnoses. The use of these
(
4) (a) Sammes, P. G.; Yahioglu, G. Nat. Prod. Rep. 1996, 13, 1-28.
(
(
1) Richardson, F. S. Chem. Rev. 1982, 82, 541-552.
(b) Parker, D. Coord. Chem. Rev. 2000, 205, 109-130. (c) Hemmila,
I.; Mukkala, V.-M. CRC Crit. Rev. Clin. Lab. Sci. 2001, 38, 441-519.
(d) Selvin, P. R. Annu. Rev. Biophys. Biomol. Struct. 2002, 31, 275-
302.
2) Gudgin Dickson, E. F.; Pollak, A.; Diamandis, E. P. J. Photochem.
Photobiol., B 1995, 27, 3-19.
(
3) Hemmil a¨ , I.; Webb, S. Drug Discovery Today 1997, 2, 373-381.
10.1021/jo0480242 CCC: $30.25 © 2005 American Chemical Society
2274
J. Org. Chem. 2005, 70, 2274-2284
Published on Web 02/16/2005

Direct Access to Polyazamacrocycles
SCHEME 1
SCHEME 2
photosensitizer antenna to enhance the luminescence of
Eu(III) ion in biological media, the terpyridine group is
a very suitable energy-absorbing and energy-transferring
-1
-1
moiety. It can be excited efficiently (ꢀ ≈ 10000 M cm )
at a wavelength of ca. 330 nm, which is a convenient
excitation wavelength for instrumental reasons related
to UV transmission of glass slides, for the use of nitrogen
laser excitation, and for reducing the amount of fluores-
cence caused by the surrounding tissue. Its lowest excited
3
-1
state (E( ππ*) ) 23000 cm ) is sufficiently high in energy
to be able to transfer excitation to the luminescence levels
of Eu(III) ion ( D , j ) 0-2). In addition, the nine
5
12
j
coordination sites reported for Eu(III) ions in aqueous
solutions may be entirely occupied by the nonadentate
structure of these ligands, preventing coordination of
other ligands (solvent or anion). Another key point to be
put forward is that the terpyridine group may be easily
functionalized at the 4-position of the central ring. As a
matter of fact, for luminescent complexes of practical use
the ligand must contain appropriate functionalization to
be covalently attached to bioactive molecules without
highlights the use of aminopolycarboxylic acyclic chain
ligands and DOTA-type macrocyclic derivatives where
a chromophoric unit is substituted on one acetic side arm
6
(
DOTA ) 1,4,7,10-tetraazacyclododecane-1,4,7,10-tet-
7
raacetate). We have noticed only a few reports about
lanthanide binding by macrocyclic compounds incorpo-
rating both an intracyclic chromophoric unit and pendant
carboxylate groups. In this family of ligands, compounds
8
1
-4 (Scheme 1) incorporating a pyridine, phenanthro-
13
altering its binding properties. For this purpose, com-
9
10
11
line, bipyridine, or bis(pyrazol-1-yl)pyridine unit as
the heterocyclic moiety into 12-24-membered macro-
cyclic structures are the main representative examples.
pounds 6-8 contain an ester or amino extracyclic moiety
and are potential precursors of amine-, acid-, or thiol-
reactive complexes. Preliminary results concerning com-
pound 5 have been published previously.14
We report here our results concerning the synthesis
and the main photophysical properties of a new series of
Eu(III) macrocyclic receptors containing a terpyridine
moiety as part of a polyamine ring with N-pendant
acetate groups (compounds 5-8, Scheme 1). Acting as a
Results and Discussion
Synthesis. As evidenced in numerous reports on the
synthesis of polyazamacrocyclic ligands, the crucial step
in the preparation of the target ligands is the macro-
cyclization reaction.15 In this study, we investigated two
strategies for the preparation of the 18-membered mac-
rocyclic ligand 5 (Scheme 2). Our first strategy was based
on the “Richman-Atkins” method, which is a time-tested
and probably the most widely used process for macroring
closure. In this procedure, the macrocyclization reaction
was conducted by reacting disodium salts of tosylated
polyamines with dihalogeno fragments in dimethyl-
formamide at elevated temperature and did not require
(
5) (a) Caravan, P.; Ellison, J. J.; McMurry, T. J.; Lauffer, R. B.
Chem. Rev. 1999, 99, 2293-2352. (b) Kiefer, G. E.; Simon, J.; Garlich,
J. R. WO P 9426754, 1994. (c) Sherry, A. D.; Kiefer, G. E. U.S. Patent
5
362476, 1994.
(
6) For examples see: (a) Ge, P.; Selvin, P. R. Bioconjugate Chem.
2
003, 14, 870-876. (b) Brunet, E.; Juanes, O.; Sedano, R.; Rodriguez-
Ubis, J.-C. Photochem. Photobiol. Sci. 2002, 1, 613-618. (c) Ozaki, H.;
Suda, E.; Nagano, T.; Sawai, H. Chem. Lett. 2000, 312-313. (d) Latva,
M.; Takalo, H.; Mukkala, V.-M.; Matachescu, C.; Rodriguez-Ubis, J.-
C.; Kankare, J. J. Lumin. 1997, 75, 149-169.
(7) For examples see: (a) Quici, S.; Marzanni, G.; Cavazzini, M.;
Anelli, P. L.; Botta, M.; Gianolio, E.; Accorsi, G.; Armaroli, N.;
Barigelletti, F. Inorg. Chem. 2002, 41, 2777-2784. (b) Beeby, A.;
Bushby, L. M.; Maffeo, D.; Williams, J. A. G. J. Chem. Soc., Dalton
Trans. 2002, 48-54. (c) Dadabhoy, A.; Faulkner, S.; Sammes, P. G. J.
Chem. Soc., Perkin Trans. 2 2000, 2359-2360. (d) Lowe, M. P.; Parker,
D. Chem. Commun. 2000, 707-708.
(12) (a) Sarkar, A.; Chakravorti, S. J. Lumin. 1995, 63, 143-148.
(b) M u¨ rner, H.-R.; Chassat, E.; Thummel, R. P.; B u¨ nzli, J.-C. G. J.
Chem. Soc., Dalton Trans. 2000, 2809-2816.
(13) For a recent example, see: (a) Manning, H. C.; Goebel, T.; Marx,
J. N.; Bornhop, D. J. Org. Lett. 2002, 4, 1075-1078. (b) Manning, H.
C.; Goebel, T.; Thompson, R. C.; Price, R. R.; Lee, H.; Bornhop, D. J.
Bioconjugate Chem. 2004, 15, 1488-1495.
(14) Galaup, C.; Couchet, J. M.; Picard, C.; Tisn e` s, P. Tetrahedron
Lett. 2001, 42, 6275-6278.
(15) Bradshaw, J. S.; Krakowiak, K. E.; Izatt, R. M. Aza-Crown
Macrocycles; Wiley: New York, 1993.
(
8) Kim, W. D.; Kiefer, G. E.; Maton, F.; McMillan, K.; Muller, R.
N.; Sherry, A. D. Inorg. Chem. 1995, 34, 2233-2243.
9) Sasamoto, K.; Horiguchi, D.; Nobuhara, M.; Mochizuki, H. Eur.
Pat. Appl. EP 493,745, 1992; Chem. Abstr. 1993, 118, 3409f.
10) Galaup, C.; Carri e´ , M.-C.; Tisn e` s, P.; Picard, C. Eur. J. Org.
Chem. 2001, 2165-2175.
11) Brunet, E.; Juanes, O.; Sedano, R.; Rodr ´ı guez-Ubis, J.-C. Org.
Lett. 2002, 4, 213-216.
(
(
(
J. Org. Chem, Vol. 70, No. 6, 2005 2275

Galaup et al.
SCHEME 3a
SCHEME 4a
a
Reagents and conditions: (a) (i) C6H5CHO, EtOH, 50 °C, (ii)
NaBH4, EtOH, 50 °C, (iii) HCl(aq) (37%), CH2Cl2; (b) BrCH2COO-
tBu, K2CO3, CH3CN, reflux; (c) Pd/C (10%), H2 (3 bar), MeOH, rt.
a template ion or the use of high-dilution techniques.16
Recent studies on the sulfonamide ring-closure process
have shown that the reaction can be more conveniently
carried out by using tosylated polyamines, potassium
carbonate as a base, and anhydrous acetonitrile as a
solvent under heterogeneous conditions.17 However, in
this strategy, it is still necessary to carry out further
alkylations on the deprotected macrocycle to obtain the
desired three-armed systems. The second strategy is an
alternative procedure and involves the triamine 11,
which presents coordinating function groups that may
interact with a metal ion. Thus, it may be possible to
control the formation of the macroring by a metal
a
Reagents and conditions: (a) 3-ClC6H4CO3H, CH2Cl2, rt, 12
h; (b) Me3SiCN, PhCOCl, CH2Cl2, rt, 12 h; (c) (i) KOH, EtOH-
H2O, reflux,12 h, (ii) H2SO4-CH3COOH, reflux, 5 h; (d) SOCl2,
MeOH, reflux, 5 h; (e) NaBH4, EtOH, reflux, 12 h; (f) PBr3, DMF,
rt, 12 h; (g) (i) nBuLi, THF, -78 °C, (ii) Bu3SnCl, -78 °C, 4 h; (h)
“
template” ion effect. An important advantage of this
method is that the acetate arms are incorporated prior
to cyclization, eliminating the need for a protection/
deprotection sequence.
2
equiv of 19, Pd(PPh3)4, toluene, reflux, 4 days; (i) NBS, AIBN,
benzene, hν, reflux, 9 h.
Starting Materials. The tosylated triamine 10 was
obtained according to the literature,18 and the synthetic
procedure of the versatile building block 11 is reported
in Scheme 3. In this route, the protection of primary
amine functions of diethylenetriamine was performed by
a one-pot reductive amination sequence.19 By using a
simplified procedure, the HCl salt of the resulting
polyamine 12 was isolated in a 94% yield. The three
secondary amine groups of 12 were alkylated with an
excess of tert-butylbromoacetate, in refluxing acetonitrile
transfer hydrogenation with ammonium formate as the
hydrogen source, but this method suffered from time-
consuming purification steps related to the formation of
side products.
The preparation of 6,6′′-bis(bromomethyl)-2,2′:6′,2′′-
terpyridine (9a) was carried out following the classical
procedure depicted in the Scheme 4a, starting from
commercial 2,2′:6′,2′′-terpyridine. The introduction of
cyano groups on the terminal pyridine moieties was
performed through the N,N′′-dioxide derivative and by
using the modified Reissert-Henze reaction.20 These first
and in the presence of K
yield. A complete trialkylation of 12 was also obtained
2
by using an organic base ( Pr NEt) in DMF at room
2 3
CO as base to give 13 in 79%
2
1
two steps were carried out according to the literature
with improved yields. Successive treatments of dicarbo-
nitrile 15 with KOH in EtOH/H O and then with a
i
temperature (63% yield). Debenzylation of 13 was readily
achieved in a quantitative yield by catalytic hydrogena-
tion at room temperature under hydrogen pressure, in
methanol, using Pd/C (10%) as catalyst. Removal of the
N-benzyl groups was also effective by using catalytic
2
mixture of sulfuric acid and acetic acid (1:1) gave the
dicarboxylic derivative 16 in 92% yield. This latter
compound was converted to its methyl ester, and the
corresponding diol 18 was finally brominated with phos-
phorus tribromide, using standard methodology. 9a was
thus obtained with an overall yield of 37%.
(
16) Richman, J. E.; Atkins, T. J. J. Am. Chem. Soc. 1974, 96, 2268-
270.
17) (a) Aime, S.; Botta, M.; Geninatti Crich, S.; Giovenzana, G. B.;
Jommi, G.; Pagliarin, R.; Sisti, M. Inorg. Chem. 1997, 36, 2992-3000.
b) Bazzicalupi, C.; Bencini, A.; Fusi, V.; Giorgi, C.; Paoletti, P.;
2
Compound 9a was also prepared by another synthetic
route, using a Stille-type coupling procedure (Scheme 4b).
In this route, 2,6-dibromopyridine was treated with 2
(
(
Valtancoli, B. J. Chem. Soc., Dalton Trans. 1999, 393-400. (c) Aime,
S.; Botta, M.; Frullano, L.; Geninatti Crich, S.; Giovenzana, G.;
Pagliarin, R.; Palmisano, G.; Riccardi Sirtori, F.; Sisti, M. J. Med.
Chem. 2000, 43, 4017-4024. (d) Aime, S.; Gianolio, E.; Corpillo, D.;
Cavallotti, C.; Palmisano, G.; Sisti, M.; Giovenzana, G. B.; Pagliarin,
R. Helv. Chim. Acta 2003, 86, 615-632.
22
equiv of 2-methyl-6-(tributylstannyl)pyridine (19) in the
(20) Fife, W. K. J. Org. Chem. 1983, 48, 1375-1377.
(21) (a) Thummel, R. P.; Jahng, Y. J. Org. Chem. 1985, 50, 3635-
3636. (b) Mukkala, V.-M.; Sund, C.; Kwiatkowski, M.; Pasanen, P.;
H o¨ gberg, M.; Kankare, J.; Takalo, H. Helv. Chim. Acta 1992, 75, 1621-
1632.
(22) Hanan, G. S.; Schubert, U. S.; Volkmer, D.; Rivi e` re, E.; Lehn,
J.-M.; Kyritsakas, N.; Fischer, J. Can. J. Chem. 1997, 75, 169-182.
(
18) Newkome, G. R.; Pappalardo, S.; Gupta, V. K.; Fronczek, F. R.
J. Org. Chem. 1983, 48, 4848-4851.
19) Sclafani, J. A.; Maranto, M. T.; Sisk, T. M.; Van Arman, S. A.
J. Org. Chem. 1996, 61, 3221-3222.
(
2276 J. Org. Chem., Vol. 70, No. 6, 2005

Direct Access to Polyazamacrocycles
SCHEME 5a
dichloro derivative is more easily available than its
dibromo counterpart.2 The methyl groups of 20b were
then brominated via NBS and AIBN in a benzene/water
mixture as previously described.25
6,27
In contrast, the attempts to synthesize compound 20d
by coupling 2 equiv of organotin compound 19 with 2,6-
dichloropyridine functionalized in the 4-position with a
CH OCH COOMe chain using the standard Pd(0) cata-
2 2
lytic conditions failed. The target terpyridine 20d was
obtained in two steps, by reduction of the 4′-ethyl ester
4
group of 20b with an excess of NaBH in ethanol and
subsequent alkylation of the hydroxy function by methyl
bromoacetate (72% and 58% yield, respectively). Although
several methods were utilized, it was not possible to
achieve the functionalization of the methyl groups of 20d
by a free radical bromination. This failure was apparently
due to competitive cleavage of the side chain. For
example, when 20d was reacted with Br
medium (C /H O), 6,6′′-dimethyl-2,2′:6′,2′′-terpyridine-
′-carbaldehyde was the only reaction product isolated
2
in a biphasic
6
H
6
2
4
after column chromatography (45% yield). Thus, dimethyl
functionalization of 20d was achieved by employing an
N,N′′-oxidation process.28 The selective oxidation of 20d
by 4 equiv of m-CPBA in dichloromethane gave the
corresponding 1,1′′-dioxide derivative 22 (Scheme 5) in
8
1% yield. Treatment of this compound with trifluoro-
acetic anhydride and an excess of anhydrous LiBr in THF
afforded the bis(bromomethylated) compound 9c in 13%
yield. The conditions for both reaction and purification
steps could be optimized and the yield improved.
a
Reagents and conditions: (a) 2 equiv of 19, Pd(PPh3)4, toluene,
reflux, 4 days; (b) NBS, AIBN, benzene, hν, reflux, 3 h; (c) NaBH4,
EtOH, reflux, 24 h; (d) NaH, BrCH2COOMe, THF, reflux, 24 h;
(
°
e) 3-ClC6H4CO3H, CH2Cl2, rt, 12 h; (f) (i) (CF3CO)2O, CHCl3, 40
C, 5 h, (ii) LiBr, THF-DMF, rt, 40 h.
Macrocyclization Reaction. The initial route to
obtain the 18-membered macrocyclic ligand 5 involved
the treatment of the tosylated triamine 10 with dibro-
3 4
presence of (PPh ) Pd for 4 days in toluene. Very recently,
2 3
mide 9a in the presence of K CO and MeCN (Scheme
Schubert reported that this coupling reaction afforded
mainly 6-bromo-6′-methyl-2,2′-bipyridine, resulting from
a single coupling step.23 It was suggested that the activity
of the bromo function was reduced in this intermediate
due to the steric and electronic influence of the pyridine
ring at the 6-position. In our hands, this reaction was
clean and the desired 6,6′′-dimethyl-2,2′:6′,2′′-terpyridine
6). This reaction did not give the 1:1 cyclization product,
but it mainly afforded the dimeric 36-membered macro-
cycle 23 in 20% yield. Furthermore, no evidence for the
monomeric 18-membered macrocycle was observed by
modifying the nature of the base metal ion (Na2CO3
instead of K CO ); only higher amounts of acyclic prod-
2
3
ucts were obtained. This orientation of the sulfonamide
(20a) was isolated by liquid chromatography on alumina
cyclization reaction is in marked contrast with the
in high yield (75%). The methyl groups of 20a were
monobrominated via classical radical conditions (NBS,
AIBN, and under irradiation). In this reaction, the use
of benzene as solvent24 limits multiple bromination,
especially the formation of an unsymmetrical (dibromo-
methyl)methyl derivative, making the purification pro-
cess easier. In this route and starting from commercially
available 2-bromo-6-methylpyridine, compound 9a was
obtained with an overall yield of 41%.
predominant 1:1 macrocycle formation observed by Aime17a
or us29 for analogous macrocycles where pyridine or 2,2′-
bipyridine moieties are substituted for the terpyridine
moiety. Following the same procedure, the corresponding
12- or 15-membered macrocycles were isolated in 90%
and 77% yield, respectively. These results support the
earlier observations of Iwata and Kuzuhara30 indicating
that the chain length of the two starting reagents is one
of the major factors playing a role in this macrocyclization
process. These authors pointed out that the best results
were obtained by coupling the electrophile containing the
shortest chain length with the nucleophile containing the
longest chain.
The Stille-type cross-coupling procedure was also used
for the introduction of an ester group into the central 4′-
position of 6,6′′-dimethyl-2,2′:6′,2′′-terpyridine (Scheme
5
). The use of 2,6-dichloroisonicotinic ethyl ester (21) as
the central building block instead of the corresponding
dibromo derivative25 led to the 6,6′′-dimethyl-2,2′:6′,2′′-
terpyridine 4′-ethyl ester (20b) in similar yield (63% and
In the second strategy (Scheme 6), a marked ion effect
was found facilitating the macrocyclization process in
2
5
5
5%, respectively). This is worth noting since the
(26) Henegar, K. E.; Ashford, S. W.; Baughman, T. A.; Sih, J. C.;
Gu, R.-L. J. Org. Chem. 1997, 62, 6588-6597.
(
27) Mello, J. V.; Finney, N. S. Org. Lett. 2001, 3, 4263-4265.
(
23) Heller, M.; Schubert, U. S. J. Org. Chem. 2002, 67, 8269-8272.
24) Bedel, S.; Ulrich, G.; Picard, C. Tetrahedron Lett. 2002, 43,
(28) Lehn, J.-M.; Regnouf de Vains, J.-B. Helv. Chim. Acta 1992,
75, 1221-1236.
(
1
1
697-1700.
(29) Galaup, C.; Tisn e` s, P.; Picard, C. Unpublished results.
(30) Iwata, M.; Kuzuhara, H. Bull. Chem. Soc. Jpn. 1989, 62, 198-
210.
(
25) Bedel, S.; Ulrich, G.; Picard, C.; Tisn e` s, P. Synthesis 2002,
564-1570.
J. Org. Chem, Vol. 70, No. 6, 2005 2277

Galaup et al.
SCHEME 6a
a
Reagents and conditions: macrocyclization reactions, [reactants] ) 2.2 × 10-3 M, M2CO3, CH3CN, reflux, 12 h; (a) CF3COOH, CH2Cl2,
rt, 12-24 h; (b) (i) 2-(4-aminophenyl)ethylamine, NaCN (catalytic), MeOH, 100 °C, 4 days, (ii) NaOH, EtOH-H2O, rt, 24 h.
favor of the targeted macrocycle. As a matter of fact,
condensation of the building block 11 with dibromide 9a
dominated by peaks at m/z 703.5 and 725.5 (base peak)
+
+
corresponding to the species [M + H] and [M + Na] ,
respectively. The fragmentations of these two ions are
governed by the usual rupture of the tert-butyl ester
bond, which leads to the observation of one, two, and
three successive losses of 56 Da (C H fragment). In the
was tested with various metal carbonates (M
2
CO
3
, M )
Li, Na, or K) in refluxing CH
high-dilution techniques ([reactants] ) 2.3 × 10 M).
The procedure using Na CO as a base generated mainly
3
CN and without the use of
-
3
2
3
4
8
the desired 18-membered macrocycle 24, which was
isolated, after column chromatography, as its NaBr
complex in 56% yield. When a lithium ion was used, the
+
ESI MS spectrum of 25, recorded in the same conditions
as that of 24, dimeric monocharged ions [2M + H] and
2M + Na] and dimeric doubly charged ion [2M + 2H]
+
+
2+
[
1
:1 macrocyclization process was also favored, but this
(
base peak) were successfully detected at m/z 1406, 1428,
reaction was accompanied by polymerization to a higher
extent. Under similar reaction conditions and by using
and 703.5, respectively. The dimeric structure of 25 was
confirmed by the observation in the same spectrum of a
series of six peaks corresponding to the loss of one to six
2 3
K CO , formation of the 18-membered monomer structure
was not observed, but the 36-membered dimer structure
free of potassium ion 25 was isolated in 37% yield. These
experimental results suggest a metal template ion effect
as a dominant factor in this 1:1 cyclization reaction, as
recently reported31 in a macrobicyclization procedure
leading to polyamine cryptands incorporating bipyridine
2
8 Da units from the doubly charged ion at m/z 703.5,
accordingly with the presence of six tert-butyl ester
functions in this compound. These 1:1 and 2:2 macro-
1
cycles may also be easily distinguished by their H NMR
1
and UV spectra. Their H NMR spectra exhibited sig-
nificant differences for the heteroatomic hydrogens.
Especially, the protons at the 3,3′′-positions of the terpy-
ridine unit are shifted to higher field in 24 as compared
to the corresponding dimer 25 (7.99 vs 8.32 ppm). This
suggests that the orientation of the terpyridinyl moiety
in the smaller macrocycle 24 is approaching a cis-cis
conformation.22 The observation of two distant UV ab-
sorption bands in MeOH for 24 (λ ) 281 and 307 nm)
and only one for 25 (λ ) 286 nm) is also consistent with
a preferential cis-cis conformation of the terpyridine unit
in 24. This was suggested by the previous study of UV
2 3
units. The best result obtained with Na CO can be
+
probably explained by an optimum fit between Na and
the 18-membered cavity. This is supported by the ability
3+
of this molecular cavity to accommodate Eu (vide infra),
+
an ion of size similar to that of Na .
The proposed monomer (M) and dimer (2M) structures
for 24 and 25, respectively, were supported by a mass
+
spectrometry study. The ESI mass spectrum of 24 was
(
31) Bencini, A.; Bianchi, A.; Giorgi, C.; Fusi, V.; Masotti, A.;
Paoletti, P. J. Org. Chem. 2000, 65, 7686-7689.
2278 J. Org. Chem., Vol. 70, No. 6, 2005

Direct Access to Polyazamacrocycles
spectra of 2,2′:6′,2′′-terpyridine and bisannealed deriva-
32
tives. These results are consistent with the participation
of the three heterocyclic nitrogen atoms of 24 in sodium
+
binding. On the other hand, complexation by Na was
accompanied by a reduction in the carbonyl stretching
-
1
frequency of only 5 cm , indicating very weak or no
ligation of the ester functions of this ligand.
Finally, acidic treatment of compound 24 gave the
triacid 5 in 77% isolated yield.
Functionalized Macrocycles. Eighteen-membered
macrocycles 6 and 7 tethered to an ester group were also
prepared by using this new synthetic approach. Conden-
sation of the triamine 11 with dibromide 9b or 9c by
2 3
using Na CO gave the NaBr complexes of the corre-
sponding macrocycle 26 or 27. Na-26 and Na-27 were
isolated in 34% and 43% yield, respectively, after puri-
fication by column chromatography. Mild hydrolysis of
the tert-butyl esters with trifluoroacetic acid at room
temperature gave the triacid derivatives 6 and 7 in 87%
and 65% yield, respectively. The terpyridine macrocycle
tethered to an aromatic amino group, compound 8, was
synthesized starting with tetraester macrocycle 26
FIGURE 1. Corrected excitation (250-450 nm, λ ) 618 nm)
em
and emission (550-750 nm, λex ) 349 nm) spectra of the Eu-6
-
6
complex solution (1 × 10 M in borate buffer, pH 8.6).
Excitation and emission band-passes 2.5 nm, delay time 0.1
5
ms, gate time 0.4 ms. The emission bands arise from the D
0
7
J
f F transitions; the J values are shown on the spectrum.
TABLE 1. Luminescence Dataa for Complexes Eu-(5-8)
and Hydration Numbers q
(
Scheme 6). For the aminolysis of the ethyl ester group
λexc
τH O
τD O
ΦH O
2
2
2
b
qH2Oc qH2Od
of 26, we took advantage of the method reported by
compd (nm) (ms) (ms)
(%)
F2 F1
I /I
3
3
Hoegberg et al. In this method, the cyanide anion was
used as a mild nucleophilic catalyst in the aminolysis of
aromatic esters with primary aliphatic amines. Reaction
of 26 with 2-(4-aminophenyl)ethylamine was carried out
in methanol and in the presence of a catalytic amount of
NaCN. Subsequent saponification of the remaining three
tert-butyl ester functions was conducted on the crude
condensation product and afforded the targeted macro-
cycle 8 after column chromatography (29% yield, two
steps).
Photophysical Properties of Europium Com-
plexes. To investigate the potentiality of these ligands
to photosensitize the europium ion and to determine the
extent of its protection against water interactions, equiva-
Eu-5
Eu-6
Eu-7
Eu-8
334
349
329
344
1.06
1.07
0.92
0.45
1.70
1.77
1.47
0.55
17.5
13.4
15.0
4.0
3.1
3.4
3.4
3.3
0.37
0.39
0.43
0.42
0.05
0.07
0.11
0.10
a In aerated borate buffer solution (0.05 M, pH 8.6) at 295 K.
b
5
7
IF /IF is the ratio of the integrated emissions from the D0 f F2
2
1
5
7
c
and D0 f F1 transitions. Calculated by using the following
3
4 d
equation: q ) 1.05(1/τH O - 1/τD O).
Calculated by using the
2
2
2
3
6
following equation: q ) 1.11(1/τH O - 1/τD O - 0.31).
2
solvent provides an experimental tool to determine the
degree to which these new ligands are capable of shield-
ing the ion from the environment. By comparison of the
luminescence lifetimes in protonated and deuterated
water and by using the conventional “Horrocks equa-
lent amounts of europium (in the form of EuCl
3
‚6H
2
O)
34
tion”, the hydration number (i.e., the number of coor-
-
5
were added to 1 × 10 M solutions of 5-8 in aqueous
dinated water molecules) was determined to be in the
range 0.37-0.42. These noninteger q values represent
the quenching contribution of unbound but closely dif-
fusing water molecules. Quite recently, a refined equa-
tion taking into account the effect of second-sphere water
molecules has been proposed for Eu(III) complexes, with
solution (borate buffer, pH 8.6). Both Eu-(5-8) com-
plexes gave classical europium-centered luminescence
5
spectra, with the strongest transition at 620 nm ( D
0
-to-
35
7
2
F transition) when photoexcited in the lowest energy
absorption of the heterocyclic chromophore. The similar-
ity between the absorption and excitation spectra proves
energy transfer from the excited states of the ligand to
the Eu(III) emission states. Representative excitation and
emission spectra are shown in Figure 1 for Eu-6. The
36
an estimated uncertainty on q of (0.1. The values of q
using this analysis are reduced to 0.1. These results
clearly indicate that water is expelled from the inner
coordination sphere of the europium ion in these com-
plexes and suggests that the nine binding sites provided
by the ligands 5-8, which wrap about the metal ion
uniformly, coordinate the metal ion. The overall quantum
yields of the metal-centered luminescence, Φ, upon
excitation of the terpyridine group are given in Table 1.
The Φ value found for the unsubstituted terpyridinyl
chelate 5 is relatively high and quite competitive with
those recently reported in the literature for Eu(III)
5
7
5
intensity ratios of the D
0
f F
2
transition and the D
0
7
f F
1
transition, which are a good measure of the nature
and symmetry of the first coordination sphere, are
identical in the four investigated complexes, suggesting
1
that the binding sites are the same in all cases. All the
5
emission lifetimes of the Eu ( D
0
) excited level measured
for these complexes are monoexponential, as expected for
one discrete Eu-(5-8) solution species and are in the
millisecond range (Table 1).
On the other hand, the great sensitivity of Eu3+
luminescence toward quenching by O-H oscillators of the
(
34) Horrocks, W. De W., Jr.; Sudnick, D. R. Acc. Chem. Res. 1981,
14, 384-392.
(
35) Beeby, A.; Clarkson, I. M.; Dickins, R. S.; Faulkner, S.; Parker,
D.; Royle, L.; de Sousa, A. S.; Williams, J. A. G.; Woods, M. J. Chem.
Soc., Perkin Trans. 2 1999, 493-503.
(
32) Thummel, R. P.; Jahng, Y. J. Org. Chem. 1985, 50, 2407-2412.
33) Hoegberg, T.; Str o¨ m, P.; Ebner, M.; R a¨ msby, S. J. Org. Chem.
(
(36) Supkowski, R. M.; Horrocks, W. De W., Jr. Inorg. Chim. Acta
2002, 340, 44-48.
1
987, 52, 2033-2036.
J. Org. Chem, Vol. 70, No. 6, 2005 2279

Galaup et al.
3
7
38
complexes derived from podands, macrocycles, cryp-
variations of the pendant groups, but also the azahet-
erocycle subcyclic unit. These ligands form stable lan-
3
9
40
47
tands, or polyaminocarboxylic ligands and sensitized
by various chromophores. More significantly, the func-
tionalization of the terpyridine group in ligands 6 and 7
does not change the capacity of the antenna to sensitize
efficiently the luminescence of the europium ion in
aqueous solution. By comparison, at pH 8.6, a europium
complex derived from the amino-substituted ligand 8
exhibited a weaker luminescence. This is expected, since
simple amino groups are known to quench the lumines-
cence of Eu(III) complexes by a photoinduced electron
transfer (PET) process. This PET activity is efficient even
if the amino groups are not directly attached to excited
aromatic moieties.41 It is also well established that
thanide complexes in aqueous solutions and sensitize
efficiently the luminescence of the Eu(III) ion in a
pertinent excitation wavelength region (around 337 nm).
Moreover, these complexes feature amino or ester groups
that can be linked to biomolecules by classical procedures.
We can also notice that the net charge of these complexes
is neutral, an important factor to take into account, since
positively or negatively charged complexes may lead to
nonspecific binding in biological media.
Experimental Section
General experimental data are given in the Supporting
Information.
2
further modification of the NH group into an activated
group (isocyanato derivative) or protonation of the amino
substituent suppresses this quenching.42 Effectively,
when the amino group of 8 is protonated (pH 2.0), the
luminescent properties of Eu-8 are restored, with an
emission lifetime of 0.85 ms and a proton-induced
luminescence enhancement factor of 3.6.
Because of our interest in synthesizing lanthanide
complexes that are kinetically robust to metal ion release
under physiological conditions, we have studied, by
luminescence spectroscopy, the resistance of the Eu-5
complex to dissociation at various pHs and in the
presence of competing cations or ligands. No change in
its luminescence properties was observed after several
days at room temperature in aerated water (examined
pH range 6-9), in the presence of an excess of abundant
human serum cations (especially Ca and Zn ), and in
the presence of proteins (BSA).43 On the other hand,
when Eu-5 was challenged in the presence of a 5-fold
excess of DOTA44 at pH 7.4, 35% of the complex was
dissociated after 20 days. By using Verhoeven’s method,
a conditional stability constant for Eu-5 was estimated
1
,2-Ethanediamine, N-(Phenylmethyl)-N′-[2-[(phenyl-
methyl)amino]ethyl]-, Trihydrochloride (12). This com-
pound was prepared according to a previously published
1
9
procedure with the following modifications: Benzaldehyde
(4 mL, 39.4 mmol) and diethylenetriamine (1.93 mL, 17.9
mmol) were dissolved in 140 mL of absolute ethanol, and the
mixture was heated at 50 °C for 2 h. After the mixture was
4
cooled to ambient temperature, NaBH (3.36 g, 88.8 mmol) was
added, and the resulting mixture was stirred at 50 °C for 2 h
and then at room temperature for 15 h. The solvent was
removed by rotary evaporation, and the residue was diluted
with aqueous NaOH (1 M, 100 mL) and extracted with
dichloromethane (3 × 100 mL). The combined organic phases
were washed with aqueous NaOH (1 M, 100 mL), concentrated
1
to /
2
, and acidified with aqueous HCl (concentrated, 5 mL).
The resulting precipitate was collected by vacuum filtration
and washed with dichloromethane and diethyl ether to give
after drying in vacuo at 50 °C a white powder (6.60 g, 94%):
2+
2+
19
1
mp > 250 °C (lit. mp 280 °C dec); H NMR (250 MHz, D
2
O)
δ 3.38 (s, 8H), 4.26 (s, 4H), 7.44 (s, 10H); C NMR (62.5 MHz,
O) δ 45.7, 46.3, 54.2, 132.0, 132.5, 132.6, 132.7.
3-Oxa-6,9,12-triazatetradecan-14-oic Acid, 9-[2-(1,1-
Dimethylethoxy)-2-oxoethyl]-2,2-dimethyl-4-oxo-6,12-bis-
phenylmethyl)-, 1,1-Dimethylethyl Ester (13). To a mix-
ture of 12 (3 g, 7.6 mmol) and K CO (31.8 g, 230 mmol) in
1
3
D
2
45
(
1
8
to be 10 . These preliminary data demonstrate that we
have in hand complexes which are thermodynamically
and kinetically stable species.
2
3
anhydrous acetonitrile (80 mL) was added dropwise a solution
of tert-butylbromoacetate (6.72 mL, 45.5 mmol) in anhydrous
acetonitrile (50 mL). The mixture was heated at reflux for 2 h
and stirred at room temperature overnight. Subsequently, the
reaction mixture was filtered, and the filtrate was concentrated
in vacuo. The residue was purified by chromatography on silica
gel, eluting first with dichloromethane and then with a
gradient of dichloromethane-acetonitrile (v/v 80:20), to afford
In conclusion, we present here a direct approach for
the synthesis of a new class of hexaazamacrocycles
containing an intracyclic terpyridine moiety and acetate
pendant arms. The reported methodology constitutes an
alternative to the original or related Richman-Atkins
1
7,46
procedures,
and, in principle, permits substantial
3
.76 g (79%) of the title compound as a yellow oil: R
f
) 0.22
CN, 80:20); H NMR (250 MHz, CDCl ) δ
1.43 (s, 9H), 1.45 (s, 18H), 2.76 (s, 8H), 3.23 (s, 4H), 3.31 (s,
1
(
silica, CH
2
Cl
2
/CH
3
3
(
37) Weibel, N.; Charbonni e` re, L. J.; Guardigli, M.; Roda, A.; Ziessel,
R. J. Am. Chem. Soc. 2004, 126, 4888-4896.
38) Brunet, E.; Juanes, O.; Sedano, R.; Rodr ´ı guez-Ubis, J.-C. Org.
Lett. 2002, 4, 213-216.
39) (a) Petoud, S.; Cohen, S. M.; B u¨ nzli, J.-C. G.; Raymond, K. N.
J. Am. Chem. Soc. 2003, 125, 13324-13325. (b) Bodar-Houillon, F.;
Heck, R.; Bohnenkamp, W.; Marsura, A. J. Lumin. 2002, 99, 335-
13
2
H), 3.77 (s, 4H), 7.31 (m, 10H); C NMR (62.5 MHz, CDCl
3
)
(
δ 28.2, 52.0, 52.6, 55.2, 56.0, 58.4, 80.6, 80.7, 127.0, 128.2,
-1
+
129.0, 139.2, 170.9, 171.0; IR (neat, cm ) 1733; MS (ESI ) m/z
(
+
+
(rel intens) 648.7 ([M + Na] , 19), 626.7 ([M + H] , 100). Anal.
Calcd for C36 : C, 69.09; H, 8.86; N, 6.71. Found: C,
8.78; H, 9.18; N, 6.71.
-Oxa-6,9,12-triazatetradecan-14-oic Acid, 9-[2-(1,1-
55 3 6
H N O
3
41.
(
(
6
40) Yuan, J.; Tan, M.; Wang, G. J. Lumin. 2004, 106, 91-101.
3
41) (a) de Silva, A. P.; Gunaratne, H. Q. N.; Rice, T. E. Angew.
Dimethylethoxy)-2-oxoethyl]-2,2-dimethyl-4-oxo-, 1,1-
Dimethylethyl Ester (11). A mixture of 13 (1.5 g, 2.4 mmol)
and 10% Pd/C (300 mg) in methanol (40 mL) was stirred
overnight under H (3 bar). The reaction mixture was filtered
2
over Celite, and the filtrate was concentrated in vacuo.
Chem., Int. Ed. Engl. 1996, 35, 2116-2118. (b) Gunnlaugsson, T.;
Parker, D. Chem. Commun. 1998, 511-512.
(
42) (a) Cooper, M. E.; Sammes, P. G. J. Chem. Soc., Perkin Trans.
2
2000, 1695-1700. (b) Mukkala, V.-M.; Helenius, M.; Hemmila, I.;
Kankare, J.; Takalo, H. Helv. Chim. Acta 1993, 76, 1361-1378.
43) In these experiments, the Eu-5 complex (0.01 mM) was
incubated for 10 days at 37 °C and physiological pH (HEPES buffer,
(
2+
2+
pH 7.4) in the presence of cations [Ca (126 mM), Mg (0.8 mM),
(46) Burguete, M. I.; L o´ pez-Diago, L.; Garc ´ı a-Espa n˜ a, E.; Galindo,
F.; Luis, S. V.; Miravet, J. F.; Sroczynski, D. J. Org. Chem. 2003, 68,
10169-10171.
(47) (a) Aime, S.; Cavallotti, C.; Gianolio, E.; Giovenzana, G. B.;
Palmisano, G.; Sisti, M. Org. Lett. 2004, 6, 1201-1204. (b) Couchet, J.
M.; Galaup, C.; Tisnes, P.; Picard, C. Tetrahedron Lett. 2003, 44, 4869-
4872.
Zn (0.1 mM), Na+ (140 mM), or K+ (5 mM)] or in the presence of
2+
proteins (BSA, 5 mg/mL).
23
(
44) KEu-DOTA ) 5 × 10 (Cacheris, W. P.; Nickle, S. K.; Sherry, A.
D. Inorg. Chem. 1987, 26, 958-960).
45) Werts, M. H. V.; Verhoeven, J. W.; Hofstraat, J. W. J. Chem.
Soc., Perkin Trans. 2 2000, 433-439.
(
2280 J. Org. Chem., Vol. 70, No. 6, 2005

Direct Access to Polyazamacrocycles
Compound 11 (1.07 g) was obtained as a pale yellow oil in
0.66 mmol) in degassed toluene (90 mL) was refluxed under
argon for 4 days. The resulting solution was filtered over Celite
and evaporated under reduced pressure. The brown residue
was treated with aqueous HCl (15 mL, 6 M), and the aqueous
quantitative yield: 1H NMR (200 MHz, CDCl
) δ 1.43 (s, 9H),
3
1
2
2
.44 (s, 18H), 2.67 (t, J ) 4.0 Hz, 4H), 2.81 (t, J ) 4.0 Hz, 4H),
.91 (s, 2H), 3.32 (s, 6H); 13C NMR (50 MHz, CDCl
) δ 28.1,
8.2, 47.2, 51.2, 53.6, 55.7, 80.9, 81.2, 171.0, 171.2; IR (neat,
3
suspension was extracted with CH
2
Cl
2
(3 × 100 mL). The
-1
+
+
cm ) 3328, 1734; MS (ESI ) m/z (rel intens) 468.3 ([M + Na] ,
organic layers were washed with aqueous HCl (6 M), and the
combined aqueous layers were brought to pH 9 with aqueous
+
5
), 446.3 ([M + H] , 100). Anal. Calcd for C22
43 3 6
H N O ,
0
.5H O: C, 58.13; H, 9.76; N, 9.24. Found: C, 58.15; H, 9.89;
2
NH
dissolved in CH
4
OH (concentrated). The precipitate was filtered off and
N, 9.08.
,2′:6′,2′′-Terpyridine-6,6′′-dicarbonitrile (15). 15 was
2
Cl , and the solution was dried over Na SO .
2
2
4
2
After evaporation of the solvent, the solid residue was purified
by recrystallization from cyclohexane to afford the title com-
2
1a
synthesized from 14 in 92% yield according to the published
2
1b
1
23
procedure:
H NMR (250 MHz, CDCl
3
) δ 7.75 (dd, J ) 1.0
pound (2.55 g, 75%) as a white solid: mp 170-171 °C (lit.
1
Hz, 8.0 Hz, 2H), 8.01 (t, J ) 7.9 Hz, 2H), 8.05 (t, J ) 7.9 Hz,
mp 171 °C); R
CDCl
Hz, 2H), 7.92 (t, J ) 7.8 Hz, 1H), 8.40 (d, J ) 7.8 Hz, 2H),
f
) 0.30 (alumina, toluene); H NMR (200 MHz,
1
2
1
1
H), 8.57 (d, J ) 7.8 Hz, 2H), 8.82 (dd, J ) 1.0 Hz, 8.0 Hz,
3
) δ 2.65 (s, 6H), 7.18 (d, J ) 7.6 Hz, 2H), 7.73 (t, J ) 7.7
1
3
3
H); C NMR (100 MHz, CDCl ) δ 117.5, 122.8, 124.4, 128.6,
-
1
13
33.6, 138.1, 138.8, 153.7, 157.6; IR (KBr, cm ) 2238, 1577,
562.
8.45 (d, J ) 7.8 Hz, 2H); C NMR (50 MHz, CDCl
3
) δ 21.2,
121.8, 124.3, 127.3, 140.0, 144.0, 148.9, 149.6, 156.1.
2
,2′:6′,2′′-Terpyridine-6,6′′-dicarboxylic Acid (16). To a
2,2′:6′,2′′-Terpyridine-4′-carboxylic Acid, 6,6′′-Dimeth-
yl-, Ethyl Ester (20b). A mixture of 2,6-dichloroisonicotinic
solution of 15 (300 mg, 1.06 mmol) in ethanol (19 mL) and
water (4 mL) was added KOH (594 mg, 10.6 mmol) as a solid.
The reaction mixture was refluxed for overnight, and then the
solvent was evapored under vacuum. The residue was dis-
solved in water (5 mL), and the pH was adjusted to 4 with
aqueous HCl (1 M). The precipitate was removed by filtration
and washed with cold water and acetonitrile. Subsequently,
the solid material was heated to reflux in a mixture of concd
2
6,27
acid ethyl ester
(3.2 g, 14.5 mmol), 2-methyl-6-(tributyl-
2
2
stannyl)pyridine (11.1 g, 29 mmol), and Pd(PPh ) (1.67 g,
3
4
1.45 mmol) in degassed toluene (100 mL) was refluxed under
argon for 3 days. The resulting solution was filtered over Celite
and evaporated under reduced pressure. HCl (40 mL, 6M) was
added, and the solution was washed with CH Cl (3 × 50 mL).
2
2
The aqueous phase was neutralized with solid NaHCO and
3
H
2
SO
4 3
/concd CH COOH (9 mL, 1:1) for 5 h, and the reaction
extracted with CH Cl (3 × 50 mL). The combined organic
2
2
mixture was then poured onto ice (45 mL). The product was
filtered and washed with cold water and acetonitrile. Diacid
layers were dried (MgSO ) and evaporated. The residue was
4
chromatographed on alumina, eluting with CH Cl , to afford
2
2
1
6, which was not further purified, was obtained in 312 mg
3.05 g (63%) of the title compound as a white solid: mp 134-
1
2
5
1
yield (92%) as a white solid: mp > 250 °C; H NMR (250 MHz,
DMSO-d ) δ 8.15 (dd, J ) 1.5 Hz, 7.6 Hz, 2H), 8.21 (t, J ) 7.6
Hz, 3H), 8.65 (d, J ) 7.6 Hz, 2H), 8.87 (dd, J ) 1.5 Hz, 7.6 Hz,
135 °C (lit. mp 134-135 °C); H NMR (250 MHz, CDCl ) δ
3
1.47 (t, J ) 7.1 Hz, 3H), 2.67 (s, 6H), 4.50 (q, J ) 7.1 Hz, 2H),
7.21 (d, J ) 7.6 Hz, 2H), 7.75 (t, J ) 7.7 Hz, 2H), 8.40 (d, J )
7.8 Hz, 2H), 8.97 (s, 2H).
6
-
1
2
(
H), 13.26 (s, 2H); IR (KBr, cm ) 3451, 1709, 1580, 1566; MS
+
+
FAB ) m/z (rel intens) 344.2 ([M + Na] , 100).
,2′:6′,2′′-Terpyridine-6,6′′-dicarboxylic Acid Dimethyl
Ester (17). SOCl (1 mL, 13.7 mmol) was dropped slowly into
2,2′:6′,2′′-Terpyridine-4′-methanol, 6,6′′-Dimethyl- (20c).
2
Sodium borohydride (3.29 g, 87 mmol) was added to 20b (4.82
g, 14.5 mmol) in ethanol (150 mL) cooled at 0 °C. The mixture
was then refluxed for 24 h. After evaporation under reduced
pressure, 80 mL of water was poured onto the crude material,
followed by an acidification using HCl (1 M), and then
2
cooled methanol (50 mL). After the mixture was stirred for 10
min at room temperature, 16 (1.21 g, 3.8 mmol) was added
and the mixture refluxed for 5 h. After evaporation, the residue
was dissolved in CHCl
aqueous NaHCO (saturated, 100 mL). The organic layer was
separated, and the residual aqueous layer was extracted with
CHCl
(3 × 30 mL). The combined organic extracts were dried
over anhydrous MgSO and concentrated in vacuo to give white
crystals (1.25 g, 95% yield) of compound 17: mp 254-255 °C;
3
(100 mL), methanol (10 mL), and
neutralized with solid NaHCO
tracted with CH Cl , dried over MgSO
chromatography column (alumina, elution CH
ether/AcOEt, 1:1:0 f 9:0:1) gave 3.05 g (72%) of a white solid:
3
. The organic layer was ex-
, and evaporated. A
Cl /petroleum
3
2
2
4
2
2
3
4
1
mp 125-126 °C; R
f
) 0.15 (alumina, CH
) δ 2.64 (s, 6H), 4.80 (s, 2H), 7.17 (d, J
7.6 Hz, 2H), 7.71 (t, J ) 7.6 Hz, 2H), 8.34 (d, J ) 7.7 Hz,
2 2
Cl /AcOEt, 9:1); H
NMR (250 MHz, CDCl
3
1
H NMR (250 MHz, CDCl
3
) δ 4.06 (s, 6H), 8.01 (t, J ) 7.7 Hz,
)
3
H), 8.18 (d, J ) 7.7 Hz, 2H), 8.62 (d, J ) 7.7 Hz, 2H), 8.80 (d,
13
2
H), 8.36 (s, 2H); C NMR (62.5 MHz, CDCl
3
) δ 24.3, 63.0,
1
3
J ) 7.9 Hz, 2H); C NMR (62.5 MHz, CDCl
3
) δ 53.1, 122.3,
1
18.3, 118.5, 123.2, 136.9, 152.5, 155.4, 155.7, 157.7; IR (KBr,
1
24.5, 125.3, 138.1, 138.5, 147.8, 154.7, 156.5, 166.1; IR (KBr,
-1
+
+
cm ) 3390, 1582; MS (ESI ) m/z (rel intens) 314 ([M + Na ],
-
1
cm ) 1723, 1579, 1567. Anal. Calcd for C19
9.22; H, 4.97; N, 10.90. Found: C, 59.55; H, 5.36; N, 10.52.
,2′:6′,2′′-Terpyridine-6,6′′-dimethanol (18). NaBH (610
H
15 3
N O
4, 2H
2
O: C,
+
9
5), 292 ([M + H ], 100). Anal. Calcd for C18
H, 5.88; N, 14.42. Found: C, 74.46; H, 6.03; N, 14.39.
,2′:6′,2′′-Terpyridine, 6,6′′-Dimethyl-4′-[[(methoxycar-
bonyl)methoxy]methyl]- (20d). A mixture of 20c (700 mg,
.4 mmol) and NaH (95%, 182 mg, 7.2 mmol) in THF (50 mL)
17 3
H N O: C, 74.20;
5
2
4
2
mg, 16.1 mmol) was added to a suspension of 17 (1.25 g, 3.6
mmol) in absolute ethanol (50 mL), and the mixture was
refluxed for overnight. After removal of the solvent, aqueous
2
was refluxed. After 30 min, methyl bromoacetate (228 µL, 2.4
mmol) was added and the reflux continued for 24 h. After
dilution of the crude solution in ethyl acetate (50 mL), a
saturated solution of NH Cl (10 mL) and water (20 mL) were
4
used to neutralize the media. The organic layer was extracted
with AcOEt, dried, and evaporated under reduced pressure.
3
NaHCO (saturated, 30 mL) was added, and the mixture was
brought to boiling. A 50 mL portion of water was added, and
then the cold mixture was neutralized with aqueous HCl (1
M). The precipitate was filtered off and washed with H
CH
2
O and
3
CN, providing 780 mg (74%) of the title compound as a
4
8
white solid: mp 140-142 °C (lit. mp 142-143 °C); R
silica, CH Cl /MeOH, 95:5); H NMR (250 MHz, DMSO-d ) δ
2 2 6
f
) 0.2
A chromatography column (alumina, elution CH
2 2
Cl /petroleum
1
(
ether, 1:1 f 1:0) led to 500 mg (58%) of a white solid: mp
4
7
8
.69 (d, J ) 5.8 Hz, 4H), 5.53 (t, J ) 5.9 Hz, 2H), 7.57 (d, J )
.7 Hz, 2H), 8.01 (t, J ) 7.8 Hz, 2H), 8.08 (t, J ) 7.6 Hz, 1H),
.43 (d, J ) 7.8 Hz, 2H), 8.49 (d, J ) 7.8 Hz, 2H); IR (KBr,
1
9
8-99 °C; R
CDCl ) δ 2.64 (s, 6H), 3.78 (s, 3H), 4.22 (s, 2H), 4.83 (s, 2H),
.18 (d, J ) 7.6 Hz, 2H), 7.72 (t, J ) 7.6 Hz, 2H), 8.39 (d, J )
f 2 2
) 0.30 (alumina, CH Cl ); H NMR (250 MHz,
3
7
7
5
1
-
1
cm ) 3415, 1572.
,2′:6′,2′′-Terpyridine, 6,6′′-Dimethyl- (20a). A mixture
of 2,6-dibromopyridine (3.1 g, 13 mmol), 2-methyl-6-(tributyl-
1
3
.6 Hz, 2H), 8.46 (s, 2H); C NMR (62.5 MHz, CDCl
3
) δ 24.6,
2
2.0, 67.8, 72.3, 118.4, 119.3, 123.4, 137.1, 148.1, 155.5, 156.0,
-1
+
57.9, 177.0; IR (KBr, cm ) 1751, 1581; MS (ESI ) m/z (rel
2
2
stannyl)pyridine (11.1 g, 29 mmol), and Pd(PPh
3
)
4
(0.76 g,
+
+
intens) 386 ([M + Na ], 79), 364 ([M + H ], 100). Anal. Calcd
for C21 : C, 69.41; H, 5.82; N, 11.56. Found: C, 69.05;
H, 5.91; N, 11.73.
21 3 3
H N O
(48) El-ghayoury, A.; Ziessel, R. J. Org. Chem. 2000, 65, 7757-7763.
J. Org. Chem, Vol. 70, No. 6, 2005 2281

Galaup et al.
2
,2′:6′,2′′-Terpyridine, 6,6′′-Dimethyl-4′-[[(methoxycar-
bonyl)methoxy]methyl]-, 1,1′′-Dioxide (22). Compound 20d
363 mg, 1 mmol) was added to a solution of 3-chloroperbenzoic
acid (673 mg, 3.9 mmol) in CH Cl (7 mL). The mixture was
35(50),45,47-octadecaene, 13,16,19,37,40,43-Hexakis[(4-
methylphenyl)sulfonyl]- (23). To a solution of 1,4,7-tris(p-
18
(
tolylsulfonyl)-1,4,7-triazaheptane (10) (61 mg, 0.11 mmol) in
2
2
2 3
anhydrous acetonitrile (50 mL) was added K CO (115 mg, 0.83
protected from light and stirred at room temperature for 12
h. The resulting solution was neutralized with an aqueous
mmol). The suspension was refluxed for 1 h and 30 min, then
9a (45 mg, 0.11 mmol) was added in one portion, and the
mixture was stirred at reflux overnight before filtration. The
solvent was removed by rotary evaporation, and the residue
was purified by chromatography on silica gel, eluting first with
dichloromethane and then with dichloromethane-methanol
(v/v 99:1), to afford 18 mg (20%) of the 2 + 2 macrocycle 23 as
saturated solution of NaHCO
combined organic layers were washed with water, dried over
MgSO , and evaporated under reduced pressure. Silica chro-
matography (CH Cl /MeOH, 1:0 f 9:1) yielded 320 mg (81%)
) 0.40 (silica, CH
) δ 2.60 (s, 6H), 3.76 (s, 3H), 4.21 (s, 2H),
.81 (s, 2H), 7.23-7.33 (m, 4H), 7.98 (dd, J ) 7.3, 2.1 Hz, 2H),
3 2 2
and extracted with CH Cl . The
4
2
2
1
of a yellow oil: R
f
2 2
Cl /MeOH, 9:1); H NMR
1
(
250 MHz, CDCl
3
a white solid: mp 179-180 °C; H NMR (250 MHz, CDCl ) δ
3
4
8
7
1
1.82 (s, 6H), 2.27 (s, 12H), 2.98-3.04 (m, 8H), 3.37-3.43 (m,
8H), 4.57 (s, 8H), 6.67 (d, J ) 8.1 Hz, 4H), 7.02 (d, J ) 8.2 Hz,
4H), 7.18 (d, J ) 8.2 Hz, 8H), 7.42 (d, J ) 7.2 Hz, 4H), 7.62 (t,
1
3
3
.84 (s, 2H); C NMR (100 MHz, CDCl ) δ 18.6, 52.1, 67.9,
2.1, 124.4, 125.3, 126.0, 126.2, 147.1, 147.4, 150.1, 150.5,
70.7; IR (KBr, cm-1) 1753, 1564, 1265, 850; MS (ESI ) m/z
+
J ) 8.2 Hz, 2H), 7.69 (d, J ) 8.2 Hz, 8H), 7.82 (t, J ) 7.75 Hz,
+
+
13
(
rel intens) 434 ([M + K ], 26), 418 ([M + Na ], 100), 396 ([M
4H), 8.14 (d, J ) 7.8 Hz, 4H), 8.52 (d, J ) 7.4 Hz, 4H);
C
+
+
H ], 28).
,2′:6′,2′′-Terpyridine, 6,6′′-Bis(bromomethyl)- (9a).
Route A. A mixture of dry DMF (8 mL) and PBr (150 µL,
NMR (50 MHz, CDCl ) δ 21.2, 21.5, 48.3, 48.7, 54.6, 119.9,
3
2
121.2, 123.6, 126.7, 127.3, 129.5, 129.8, 134.6, 136.1, 137.7,
-
1
137.8, 143.3, 143.4, 154.7, 155.6, 155.7, 155.8; IR (KBr, cm )
3
+
1
.58 mmol) was stirred for 15 min at room temperature. The
1598, 1569, 1343, 1161; MS (FAB ) m/z (rel intens) 1684 ([M
+
+
+
diol 18 (132 mg, 0.45 mmol) was added, and the mixture was
+ K] , 13), 1668 ([M + Na] , 100), 1646 ([M + H] , 42). Anal.
heated at 60 °C for 1 h and then stirred at room temperature
84 12 12 6 3
Calcd for C84H N O S ‚2CH OH: C, 60.40; H, 5.42; N, 9.83;
overnight. After neutralization with aqueous NaHCO
3
(satu-
S, 11.25. Found: C, 60.44; H, 4.89; N, 9.45; S, 11.22.
rated), the precipitate was filtered and washed with cold water
and acetonitrile. The solid was purified by recrystallization
13,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
from CCl
crystals: mp 203-205 °C dec; R
NMR (250 MHz, CDCl ) δ 4.65 (s, 4H), 7.49 (d, J ) 7.7 Hz,
H), 7.85 (t, J ) 7.8 Hz, 2H), 7.95 (t, J ) 7.8 Hz, 1H), 8.51 (d,
4
to afford the title compound (141 mg, 75%) as white
1
9-triacetic Acid Tris(1,1-dimethylethyl) Ester (24). To
a solution of 11 (298 mg, 0.67 mmol) in anhydrous acetonitrile
300 mL) was added Na CO (707 mg, 6.7 mmol). The suspen-
1
f
) 0.4 (alumina, toluene); H
3
(
2
3
2
sion was refluxed for 1 h, 9a (280 mg, 0.67 mmol) was added
in one portion, and the mixture was stirred at reflux overnight
before filtration. The solvent was removed by rotary evapora-
tion, and the residue was purified by chromatography on
alumina, eluting first with chloroform and then with chloro-
form-methanol (v/v 98:2 f 95:5), to afford 302 mg (56%) of
1
3
J ) 7.8 Hz, 4H); C NMR (50 MHz, CDCl
3
) δ 34.1, 120.3,
1
21.5, 123.4, 137.8, 137.9, 154.9, 156.0, 156.3. Anal. Calcd for
17 13 3 2 2
C H N Br ‚0.5H O: C, 47.69; H, 3.30; N, 9.81. Found: C,
48.05; H, 2.85; N, 9.99.
Route B. A mixture of 20a (500 mg, 1.9 mmol), NBS (850
1
mg, 4.78 mmol), and AIBN (20 mg, 0.12 mmol) in benzene (50
mL) was refluxed and lightened using a halogen lamp (150
W). The mixture was allowed to stir for 6 h, when TLC
indicated incomplete bromination of the starting material.
Therefore, more NBS (350 mg, 2 mmol) and AIBN (10 mg, 0.06
mmol) were added at this time, and the reaction mixture was
allowed to stir at reflux for another 3 h. The solvent was
evaporated under reduced pressure, then the solid residue was
the 1 + 1 macrocycle 24 as its NaBr complex: colorless oil; H
3
NMR (400 MHz, CDCl ) δ 1.09 (s, 9H), 1.22 (s, 18H), 2.77 (m,
4H), 2.90 (m, 4H), 3.17 (s br, 6H), 4.08 (s, 4H), 7.35 (d, J ) 7.1
Hz, 2H), 7.92 (t, J ) 7.6 Hz, 2H), 7.99 (d, J ) 7.2 Hz, 2H),
1
3
3
8.09 (m, 3H); C NMR (100 MHz, CDCl ) δ 27.9, 28.1, 53.1,
53.9, 56.7, 58.1, 82.0, 82.2, 120.6, 121.8, 124.0, 138.5, 139.1,
-
1
155.3, 155.5, 158.3, 171.6, 172.4; IR (neat, cm ) 1728, 1570;
+
+
MS (ESI ) m/z (rel intens) 725.5 ([M + Na] , 100), 703.5 ([M
+
+
treated with CH
by filtration. The filtrate was evaporated to dryness, and the
residue was purified by recrystallization from CHCl to afford
a (460 mg, 57%) as white crystals, which was identical with
the product obtained by route A.
,2′:6′,2′′-Terpyridine,4′-[[(Methoxycarbonyl)methoxy]-
methyl]-6,6′′-bis(bromomethyl)- (9c). To a cooled (0 °C)
solution of 22 (263 mg, 0.66 mmol) in CHCl (5.5 mL) was
2 2
Cl , and the insoluble fraction was eliminated
4 8 4 8
+ H] , 50), 669.4 ([(M - C H ) + Na] , 25), 647.4 ([(M - C H )
+
+
+ H] , 14), 613.2 ([(M - 2C H ) + Na] , 10), 591.2 ([(M -
4
8
+
+
3
4 8 4 8
2C H ) + H] , 7), 557.2 ([(M - 3C H ) + Na] , 7), 535.2 ([(M
+
9
4 8 39 54 6 6
- 3C H ) + H] , 4). Anal. Calcd for C H N O NaBr: C, 58.13;
H, 6.75; N, 10.43. Found: C, 57.93; H, 6.77; N, 10.21.
2
13,16,19,37,40,43,49,50,51,52,53,54-Dodecaazaheptacyclo-
[43.3.1.12.6.17.11.121.25.126.30.131.35]tetrapentaconta-
1(49),2,4,6(54),7,9,11(53),21,23,25(52),26,28,30(51),31,33,-
35(50),45,47-octadecaene-13,16,19,37,40,43-hexaacetic Acid
Hexakis(1,1-dimethylethyl) Ester (25). To a solution of 11
(155 mg, 0.35 mmol) in anhydrous acetonitrile (150 mL) was
added K CO (480 mg, 3.5 mmol). The suspension was refluxed
3
added dropwise trifluoroacetic anhydride (4.5 mL, 31.9 mmol).
The mixture was warmed at 40 °C for 5 h and evaporated. A
solution of LiBr (577 mg, 6.64 mmol) in THF/DMF (5.5 mL/50
µL) was then added. The resulting mixture was stirred at room
2
3
temperature for 40 h and evaporated. After addition of CH
Cl (15 mL) and water (6 mL), the extracted organic layer was
washed with H , and
O (3 × 6 mL), dried over MgSO
evaporated under reduced pressure. The crude material was
chromatographed over silica (CH Cl f CH Cl /AcOEt, 9:1) to
give 46 mg (13%) of a yellow oil: R ) 0.40 (alumina, CH Cl );
) δ 3.80 (s, 3H), 4.26 (s, 2H), 4.65
s, 4H), 4.84 (s, 2H), 7.49 (d, J ) 7.6 Hz, 2H), 7.84 (t, J ) 7.9
2
-
for 1 h, then 9a (146 mg, 0.35 mmol) was added in one portion,
and the mixture was stirred at reflux overnight before filtra-
tion. The solvent was removed by rotary evaporation, and the
residue was purified by chromatography on silica gel, eluting
first with dichloromethane and then with dichloromethane-
methanol (v/v 98:2 f 95:5), to afford 91 mg (37%) of the 2 +
2
2
4
2
2
2
2
f
2
2
1
H NMR (250 MHz, CDCl
3
1
2
macrocycle 25 as a pale yellow oil: H NMR (250 MHz,
) δ 1.42 (s, 36H), 1.48 (s, 18H), 3.25 (m, 4H), 3.52-3.63
m, 24H), 3.87 (s, 4H), 4.48 (s, 4H), 7.32 (d, J ) 7.6 Hz, 4H),
(
CDCl
3
13
Hz, 2H), 8.49-8.51 (m, 4H); C NMR (100 MHz, CDCl
3
) δ 34.4,
(
7
5
1
2.3, 68.1, 72.4, 120.0, 120.7, 123.8, 138.1, 148.6, 155.5, 155.9,
.66 (t, J ) 7.6, 2H), 7.76 (t, J ) 7.3 Hz, 4H), 8.18 (d, J ) 7.6
56.5, 170.8; IR (KBr, cm-1) 1748, 1586; MS (ESI ) m/z (rel
+
13
Hz, 4H), 8.32 (d, J ) 7.6 Hz, 4H); C NMR (100 MHz, CDCl
3
)
+
intens) 542/544/546 ([M + Na ], 50/100/50), 520/522/524 ([M
δ 28.2, 28.4, 52.3, 52.5, 56.4, 60.4, 81.0, 81.5, 119.3, 119.5,
+
+
3
H ], 8/17/8). Anal. Calcd for C21
.67; N, 8.06. Found: C, 48.25; H, 3.95; N, 8.10.
3,16,19,37,40,43,49,50,51,52,53,54-Dodecaazaheptacyclo-
19 3 3 2
H N O Br : C, 48.39; H,
1
1
20.8, 121.2, 123.0, 123.3, 137.2, 137.5, 155.2, 155.3, 155.6,
-1
+
58.8, 170.9, 171.0; IR (neat, cm ) 1730, 1570; MS (ESI ) m/z
+
+
1
(rel intens) 1427.7 ([M + Na] , 7), 1405.8 ([M + H] , 62), 703.6
2
+
2+
[
1
43.3.1.12.6.17.11.121.25.126.30.131.35]tetrapentaconta-
(49),2,4,6(54),7,9,11(53),21,23,25(52),26,28,30(51),31,33,-
([M + 2H] , 100), 675.5 ([(M - C
4
H
8
) + 2H] , 53), 647.5 ([(M
2+
2+
4 8 4 8
-2C H ) + 2H] , 50), 619.5 ([(M - 3C H ) + 2H] , 48), 591.3
2282 J. Org. Chem., Vol. 70, No. 6, 2005

Direct Access to Polyazamacrocycles
+
) + 2H]2+, 31),
+
+
(
[(M - 4C
35.3 ([(M - 6C
12: C, 66.64; H, 7.74; N, 11.96. Found: C, 66.32; H, 8.03;
N, 11.77.
4
H
8
) + 2H]2 , 41), 563.3 ([(M - 5C
4
H
8
intens) 573.0 ([M + K] , 11), 557.1 ([M + Na] , 65), 535.1 ([M
2
+
+
+
+
5
4
H
8
) + 2H] , 25). Anal. Calcd for C78
H
108
-
31 6 6
+ H] , 100); HRMS-FAB [M + H] m/z calcd for C27H N O
535.23051, found 535.23189.
N
12
O
1
3,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
1
3,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
19-triacetic Acid, 4-(Ethoxycarbonyl)- (6). Compound 26
(35 mg, 0.04 mmol) was dissolved in a mixture of CH Cl /CF -
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
1
9-triacetic Acid, 4-(Ethoxycarbonyl)-, Tris(1,1-dimeth-
2
2
3
ylethyl) Ester (26). To a suspension of 11 (173 mg, 0.39
mmol) and Na CO (410 mg, 3.9 mmol) in anhydrous aceto-
COOH (5 mL, 1:1). The solution was stirred for 24 h at room
temperature. After evaporation of the solvent and the excess
of acid, the residue was purified by chromatography on
reversed-phase silica (0.1% TFA in H O/CH OH, 80:20) to
2
3
2
5
nitrile (170 mL) was added dropwise a solution of 9b (190
mg, 0.39 mmol) in anhydrous acetonitrile (10 mL), and then
the mixture was stirred at reflux for 48 h. After filtration, the
solvent was removed by rotary evaporation, and the residue
was chromatographed on alumina, eluting with chloroform-
methanol (v/v 99:1 f 90:1). The combined fractions were
evaporated and triturated with petroleum ether to afford a
residue that was purified by recrystallization from toluene,
yielding 116 mg of the 1 + 1 macrocycle 26 as its NaBr complex
2
3
1
afford 21 mg (87%) of 6 as a colorless oil: H NMR (250 MHz,
D O) δ 1.40 (t, J ) 7.1 Hz, 3H), 3.44 (m, 4H), 3.56 (m, 4H),
2
3.61 (s, 4H); 3.72 (s, 2H), 4.43 (s, 4H), 4.50 (q, J ) 7.3 Hz,
2H), 8.01 (d, J ) 6.8 Hz, 2H), 8.64 (m, 4H), 8.92 (s, 2H); 13
C
NMR (50 MHz, D
2
O) δ 15.8, 53.0, 54.6, 56.3, 57.0, 58.2, 66.4,
1
1
6
27.5, 127.7, 131.1, 145.7, 149.2, 150.9, 152.1, 154.8, 167.0,
+
+
72.4, 176.0; MS (FAB ) m/z (rel intens) 629 ([M + Na] , 100),
(
(
1
4
34% yield): white powder; mp 185-187 °C; R
f
) 0.23
+
+
+
07 ([M + H] , 21); HRMS-FAB [M + Na] m/z calcd for
Na 629.23358, found 629.23341.
3,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
9-triacetic Acid, 4-[[(Methoxycarbonyl)methoxy]methyl]-
1
alumina, CHCl
3
/MeOH, 95:5); H NMR (250 MHz, CDCl ) δ
3
30 34 6 8
C H N O
.02 (s, 9H), 1.16 (s, 18H), 1.45 (t, J ) 7.1 Hz, 3H), 2.73 (m,
H), 2.87 (m, 4H), 3.12 (s, 6H), 4.05 (s, 4H), 4.49 (q, J ) 7.1
1
Hz, 2H), 7.38 (d, J ) 7.0 Hz, 2H), 7.92 (t, J ) 7.4 Hz, 2H),
1
(
7
.99 (d, J ) 7.4 Hz, 2H), 8.49 (s, 2H); 13C NMR (50 MHz,
CDCl ) δ 14.4, 27.7, 27.9, 52.9, 53.8, 56.5, 57.8, 62.6, 81.8, 82.0,
20.5, 123.7, 124.4, 138.5, 140.6, 154.2, 156.5, 158.4, 164.6,
-
5
7). Compound 27 (28 mg, 3.1 × 10 mol) was solubilized in
3
CH Cl /TFA (1:1, 14 mL) and the resulting solution stirred at
2
2
1
1
room temperature overnight. After evaporation, the crude
material was dissolved in a minimal amount of methanol and
poured onto THF. The precipitate was centrifuged and washed
with THF before being evaporated to dryness, yielding 13 mg
-
1
+
71.4, 172.5; IR (KBr, cm ) 1724, 1577; MS (ESI ) m/z (rel
+
+
intens) 797.5 ([M + Na] , 100), 775.5 ([M + H] , 64), 741.5
+
+
(
(
(
[(M - C
4
H
8
) + Na] , 15), 719.5 ([(M - C
4
H
8
) + H] , 9), 685.4
8
+
+
[(M - 2C
[(M - 3C
4
H
H
8
) + Na] , 6), 663.4 ([(M - 2C
4
H
H
) + H] , 4), 629.4
(
65%) of a brown oil: analytical HPLC (column CC125-3 MN
C18 HD 5 µm, solvent 0.1% TFA in H O/MeOH, 85:15, flow
rate 0.6 mL/mn): t ) 5.6 min (95% of total chromatogram
integration); H (250 MHz, D O) δ 3.38 (m, 4H), 3.64 (m, 6H),
.80 (s, 4H), 3.88 (s, 4H), 4.47 (s, 3H), 4.76 (s, 2H), 5.09 (s,
H), 7.89 (d, J ) 7.9 Hz, 2H), 8.37 (t, J ) 7.9 Hz, 2H), 8.51 (d,
J ) 7.9 Hz, 2H), 8.66 (s, 2H); MS (FAB ) m/z (rel intens) 675
[M + K ], 78), 661 ([M - CH
M + K] m/z calcd for C31
75.21856.
3,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
9-triacetic Acid, 4-[[N-[2-(4-Aminophenyl)ethyl]amino]-
+
+
4
8
) + Na] , 3), 607.3 ([(M - 3C
4
8
) + H] , 3). Anal.
2
Calcd for C42
58 6 8
H N O NaBr: C, 57.47; H, 6.66; N, 9.57. Found:
R
C, 57.73; H, 6.67; N, 9.73.
3,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
9-triacetic Acid, 4-[[(Methoxycarbonyl)methoxy]meth-
1
2
1
3
2
1
+
yl]-, Tris(1,1-dimethylethyl) Ester (27). A mixture of 11 (34
+
+
+
(
[
6
2
+ K ], 100); HRMS-FAB
H N O K 675.21809, found
-
5
-5
mg, 7.7 × 10 mol) and Na
2
CO
3
(82 mg, 77 × 10 mol) in
+
36 6 9
CH
7
3
CN (30 mL) was refluxed for 30 min, and then 9c (40 mg,
-
5
.7 × 10 mol) in acetonitrile (5 mL) was added. The reflux
1
was continued for 48 h, and then the solution was evaporated
to dryness. Purification over a reversed-phase column (Hy-
1
perprep, 0.1% TFA in H
2 3
O/CH CN, gradient from 30:70 to 10:
carbonyl]- (8). A mixture of compound 26 (150 mg, 0.17
mmol) with NaCN (catalytic) and 2-(4-aminophenyl)eth-
ylamine (125 µL, 0.95 mmol) in methanol (2 mL) was heated
at 100 °C for 100 h in a sealed tube. After evaporation to
dryness, the residue was chromatographed on silica gel, eluting
with chloroform-methanol (v/v 80:20). The combined fractions
were evaporated and triturated with petroleum ether to afford
9
0, flow rate 15 mL/min) afforded 27 mg (43%) of the desired
1
product as its NaBr complex: colorless oil; H NMR (250 MHz,
CDCl
(
7
7
2
1
3
) δ 1.07 (s, 9H), 1.20 (s, 18H), 2.60-3.00 (m, 8H), 3.12
s, 6H), 3.53 (s, 3H), 4.03 (s, 4H), 4.32 (s, 2H), 4.88 (s, 2H),
.29 (d, J ) 7.6 Hz, 2H), 7.86 (t, J ) 7.6 Hz, 2H), 7.98 (d, J )
.6 Hz, 2H), 8.07 (s, 2H); 1 C NMR (100 MHz, CDCl
3
) δ 27.7,
3
8.1, 51.9, 52.9, 53.7, 56.5, 57.9, 68.1, 71.7, 81.8, 82.0, 119.7,
20.4, 123.7, 138.2, 149.9, 155.0, 155.6, 158.0, 171.3, 172.2;
5
f 3
6 mg of a white solid: R ) 0.22 (silica, CHCl /MeOH, 90:
+
+
+
+
10); MS (ESI ) m/z (rel intens) 887.5 ([M + Na] , 100), 865.6
MS (ESI ) m/z (rel intens) 827.6 ([M + Na ], 100), 805.5 ([M
+
+
+
+
([M + H] , 44). A solution of this crude product in a mixture
+
H ], 78); HRMS-FAB [M + Na ] m/z calcd for C43
H
H
60
N
N
6
O
O
9
-
-
2
of H O/MeOH (10 mL, 5:5) with NaOH (0.2 g) was stirred at
Na 827.43195, found 827.43238. Anal. Calcd for C43
60
6
9
room temperature for 24 h. After evaporation to dryness, the
residue was purified by chromatography on reversed-phase
NaBr: C, 56.89; H, 6.66; N, 9.26. Found: C, 56.55; H, 6.45;
N, 9.57.
silica (0.1% TFA in H
2 3
O/CH OH, 80:20 to 50:50) to afford 35
1
3,16,19,25,26,27-Hexaazatetracyclo[19.3.1.12.6.17.11]-
heptacosa-1(25),2,4,6(27),7,9,11(26),21,23-nonaene-13,16,-
9-triacetic Acid (5). Compound 24 (85 mg, 0.1 mmol) was
dissolved in a mixture of CH Cl /CF COOH (10 mL, 1:1). The
1
mg (29% over two steps) of 8 as a colorless oil: H NMR (250
MHz, D
2
O) δ 3.01 (t, J ) 6.2 Hz, 2H), 3.53-3.73 (m, 12H),
1
3
.76 (m, 4H), 4.52 (s, 4H), 7.30 (d, J ) 8.2 Hz, 2H), 7.44 (d, J
2
2
3
13
)
8.3 Hz, 2H), 7.96 (d, J ) 6.1 Hz, 2H), 8.53 (m, 6H); C NMR
solution was stirred for 15 h at room temperature. After
evaporation of the solvent and the excess of acid, the residue
was dissolved in methanol (5 mL), and diethyl ether was
added, resulting in the formation of a precipitate, which was
isolated after centrifugation: white solid; yield 41 mg (77%);
analytical HPLC (column CC70-3MN C18 HD, solvent 0.1%
(62.5 MHz, D
2
O) δ 36.7, 43.9, 53.6, 54.7, 56.5, 57.6, 58.7, 125.7,
1
1
+
25.9, 127.5, 130.8, 133.2, 143.0, 148.0, 149.3, 152.0, 153.2,
+
54.5, 168.8, 173.3, 175.8; MS (ESI ) m/z (rel intens) 735 ([M
+
+
K] , 60); HRMS-FAB [M + Na] m/z calcd for C36
40 8 7
H N O -
Na 719.29177, found 719.29092.
HCOOH in H
min (98% of total chromatogram integration); H NMR (200
MHz, D O) δ 3.0-4.0 (m, 14H), 4.85 (s, 4H), 7.7 (m, 2H), 8.27-
2
O/CH
3
OH, 95:5, flow rate 0.6 mL/min) t
R
) 1.42
Procedure for the Preparation of the Europium Com-
1
plexes: The Eu(III) neutral complexes of macrocycles 5-8
2
3 2
were prepared by the addition of the EuCl ‚6H O salt (1 equiv)
1
3
8
5
1
.40 (m, 4H), 8.59 (m, 3H); C NMR (100 MHz, D
2
O) δ 51.5,
to the aqueous solution of the ligand. This solution was then
-6
3.2, 55.0, 55.8, 58.3, 124.2, 125.4, 127.9, 141.5, 149.0, 151.4,
adjusted at a final concentration of 1 × 10 M in borate buffer
71.0, 177.8; IR (KBr, cm-1) 3427, 1680; MS (ESI ) m/z (rel
+
(0.05 M, pH 8.6).
J. Org. Chem, Vol. 70, No. 6, 2005 2283

Galaup et al.
Supporting Information Available: General experimen-
6, and 8 (PDF). This material is available free of charge via
1
tal data, MS and H NMR spectra for compounds 24 and 25,
the Internet at http://pubs.acs.org.
1
and H NMR spectra for compounds 12, 16, 18, 20a, 20b, 22,
JO0480242
2284 J. Org. Chem., Vol. 70, No. 6, 2005