Controlled regioselective amination of peryleneimides

Article abstract of DOI:10.1002/ejoc.201403299

Perylenediimides (PDIs) and perylenemonoimide diesters (PMIs) can be selectively substituted at the 1,6- or 7,12-positions of the bay region, respectively, by direct amination reactions. The reactions proceed by the formation of a perylene radical anion and its subsequent oxidation, and the yields range from 20-97%. The amination can be tuned to obtain either mono- or disubstituted perylenes by varying the oxidants involved. The presence of the imide cycle is crucial for the transformation, although the amination occurs regioselectively at the bay-region positions distant from the imide cycle.

Full text of DOI:10.1002/ejoc.201403299

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Date: 11-12-14 11:37:53
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FULL PAPER
DOI: 10.1002/ejoc.201403299
Controlled Regioselective Amination of Peryleneimides
Lijo George,[a] Zafar Ahmed,[a] Helge Lemmetyinen,[a] and Alexander Efimov*[a]
Keywords: Amination / Perylenes / Polycycles / Regioselectivity / Radical anions / Imides
Perylenediimides (PDIs) and perylenemonoimide diesters
(PMIs) can be selectively substituted at the 1,6- or 7,12- posi-
tions of the bay region, respectively, by direct amination re-
actions. The reactions proceed by the formation of a perylene
radical anion and its subsequent oxidation, and the yields
range from 20–97%. The amination can be tuned to obtain
either mono- or disubstituted perylenes by varying the oxi-
dants involved. The presence of the imide cycle is crucial for
the transformation, although the amination occurs regio-
selectively at the bay-region positions distant from the imide
cycle.
moiety can later be hydrolyzed through an acidic hydrolysis
to form a second anhydride group,[14] which can be used to
prepare new asymmetric PDIs with two different N-substi-
tuted groups.[11e] The diester groups can also be hydrolyzed
to dicarboxylic acids, which can in turn be used to prepare
self-assembled monolayers (SAMs) for organic solar cells.
Similarly, despite the established significance and poten-
tial of PTCDA, a lack of solubility in organic solvents has
kept its usage somewhat restricted. In a BASF patent
(1997), Böhm et al. reported a procedure for the 1,7-di-
bromination, imidation, and subsequent replacement of
“bay–region” bromine atoms with alkyne or phenoxy
groups.[15] This method was extensively used in many labs
to synthesize bay-functionalized PDIs until 2004 when
Wuerthner et al. pointed out the presence of a regioisomeric
impurity, namely, the 1,6-isomer, in ca. 20–25%.[16] Later,
many research groups isolated and characterized 1,6- and
1,7-regioisomers of dipiperidinyl-, diphenoxy-, and dipyr-
rolidinyl-substituted PDIs[17a,17b] and demonstrated that the
1,6- and 1,7-isomers might have significantly different
photochemical properties.[17c–17f]
Much effort has been paid to the isolation of individual
isomers, mostly 1,7-substituted, but no approaches to the
synthesis of isomerically pure PDIs were proposed.[18a–18j]
Furthermore, as there was no method to synthesize prefer-
entially the 1,6-isomers of peryleneimides, the knowledge of
their properties and potential applications was poor. This
situation changed dramatically in 2013 when the direct
amination of PDIs was reported.[19a] Very recently, Rauch
et al. reported the synthesis of a regioisomerically pure 1,6-
isomer by a Cu-catalyzed amination.[19b] However, these
two reports are somewhat controversial in terms of their
reaction mechanisms and product structures.
Introduction
Since their discovery, perylenetetracarboxylic diimides
(PDIs) have attracted the interest of industry and academia.
Good thermal and photostability, high fluorescence quan-
tum yields, high molar absorption, and excellent redox
properties are a few characteristics that have inspired
chemists to focus their attention on these versatile organic
molecules.[1,2] PDIs have been utilized extensively in a
variety of high-tech applications such as photovoltaics,[3]
field-effect transistors,[4] biosensors,[5] organic solar cells,[3b]
organic light-emitting diodes,[6] optical switches,[7] and mo-
lecular wires.[8] PDIs have also been used in several other
applications, such as artificial photosynthetic systems,[9]
with controlled supramolecular architectures through their
high tendency for π–π stacking.[10] Similarly, perylenemono-
imides (PMIs) are useful precursors for asymmetric
perylene dyes. Their syntheses from commercially available
perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) as
well as their halogenation and substitution have been de-
scribed.[11] PMI dyes had been used in molecular photonic
switches and light-harvesting studies.[12] The major hurdle
in the use of perylenemonoimide dyes had been their poor
solubility in organic solvents. Various approaches such as
the introduction of alkylated N-aryl groups or aryloxy sub-
stituents at the perimeter of perylene have been used to im-
prove solubility.[11c] The solubility of PMI dyes can be in-
creased dramatically by the introduction of a diester moiety
to the perimeter of the molecule.[13] The incorporation of a
diester moiety not only resolves the solubility issue but also
makes the dyes more versatile. For example, the diester
[a] Department of Chemistry and Bioengineering, Tampere
University of Technology,
Herein, we report the controlled highly regioselective
amination of perylene mono- and diimides; isomerically
pure 7-pyrrolidinyl and 1,6-dipyrrolidinyl derivatives are
synthesized, and the substitution reaction can either be cat-
Tampere, Finland
E-mail: alexandre.efimov@tut.fi
www.tut.fi/keb
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201403299.
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FULL PAPER
alyzed by metal complexes or run catalyst-free. Depending Amination of PDIs
on the substrates and the desired product (mono- or disub-
While studying different substitution reactions, we
stituted), the reaction can be performed either at room tem-
perature with KMnO4 or atmospheric oxygen as an in situ
oxidant or as a one-pot, two-step process with subsequent
oxidation by pyridinium dichromate (PDC). In either case,
the method is highly attractive as it does not require any
halogen (or other) leaving group for the substitution to
occur, and the reaction conditions are mild. Unlike the pre-
viously reported work, in our case, the substitution occurs
at the bay region instead of the 2,5-positions of perylene[19a]
and can also proceed without catalyst.[19b]
noticed that a solution of dioctyl PDI 1 in neat pyrrolidine
under argon slowly turned from red to blue upon heating.
After the vial was opened and the solution was exposed to
air, the color changed rapidly from blue to reddish, and
green monopyrrolidine PDI 5a was recovered from the reac-
tion mixture along with the starting material 1. Our
attempts to isolate “the blue intermediate” for NMR spec-
troscopy analysis were unsuccessful, as the compound
proved to be very air sensitive. However, in situ detection
by UV/Vis spectroscopy was possible. A small amount of
PDI in thoroughly argon-purged pyrrolidine was heated at
60 °C in a sealed cuvette, and the gradual changes in the
absorption spectra were recorded. As can be seen in Fig-
ure 1, the two peaks of PDI 1 at λ = 450 and 550 nm
decreased with time and were completely gone after 5 h.
Instead, the newly formed compound had distinct absorp-
Results and Discussion
Synthesis of Precursors
The precursors 1, 1Ј, and 4 were synthesized from com- tion maxima at λ = 720 and 800 nm. A very similar absorp-
mercially available PTCDA by slight modification of pro- tion profile was reported for the chemically and electro-
cedures reported previously.[18g,20] The treatment of chemically generated perylenediimide radical anion by dif-
PTCDA with imidazole and the desired amine at elevated ferent groups.[21a–21d] After exposure of the solution to air,
temperature yielded the N-alkylated PDIs 1 and 1Ј in good the bands at λ = 720 an 800 nm disappeared, the bands
yields. The perylene tetraester (PTE) 2 was obtained by at λ = 450 and 550 nm were partly restored, and a broad
esterification of PTCDA with an alkanol and alkyl halide in absorbance of monopyrrolidyl PDI 5a appeared in the spec-
a homogeneous solution.[18g] The PTE was then selectively trum. This observation allowed us to suggest that the reac-
hydrolyzed by p-toluenesulfonic acid (pTsOH) to yield the tion proceeds by a radical anion pathway with separate
monoanhydride–diester 3 as a precipitate, which upon imid- stages for the formation of the intermediate and its oxid-
ization with n-octylamine and imidazole produced the PMI ation to the final product.
diester 4 as a dark red solid in 68% yield.[18g,20] The crucial
To the best of our knowledge, the direct amination of an
step in the synthesis of 4 was the selective hydrolysis with unsubstituted aromatic core is not very common in organic
pTsOH, as even a slight excess of pTsOH, the wrong reac- chemistry. Similar reactions on smaller aromatic rings are
tion temperature, or an inappropriate solvent resulted in the described as “oxidative amination” and have received
formation of PTCDA. A mixture of toluene and hexane limited attention.[22a,22b] In the work of Verbeeck et al.,[22a]
(5:1 v/v), 1.2 equiv. of pTsOH, and a reaction temperature the amination is thought to proceed by a two-step
of 100 °C were the optimal conditions, which prevented the mechanism: σH-adduct formation followed by an oxidative
second hydrolysis.
rearomatization. For the direct aminations of perylenes at
2
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Controlled Regioselective Amination of Peryleneimides
Figure 1. (a) Absorption profile for radical anion formation and oxidation of dioctyl PDI 1 in pyrrolidine. (black dashes: 0 h, short dark
gray dashes: 1 h, dark gray dash dot dot: 5 h, black dots: 48 h, black solid line: vial opened). (b) Absorption of unsubstituted 1 (black
solid line), monopyrrolidyl 5a (gray dashes), and dipyrrolidyl 5b (dark gray dots) dioctyl PDIs.
the bay region reported by Langhals and Rauch, two dif-
ferent reaction mechanisms have been proposed, namely, a
Chichibabin-like[19a] reaction resulting in a perisubstitution
of PDI or a Cu-catalyzed radical cycle, which produces bay-
substituted derivatives.[19b]
First, we decided to test the catalyst-free reaction
(Scheme 1) by preparation of an intermediate under an
inert atmosphere and subsequent oxidation. PDI 1 was
heated in pyrrolidine under an inert atmosphere for 5 h at
60 °C, and a subsequent oxidation with pyridinium di-
chromate (PDC) gave 20–70% yield of 5a. The formation
of product 5a proves that the reaction proceeds through
the radical anion. However, the disubstituted compound 5b
appeared only in a trace amount in this case.
Scheme 2. Regioselective amination of PDIs.
The effect of the oxidizing agent was studied next. When
PDC was used as the in situ oxidant, the yield of monopyr-
rolidyl PDI 5a was 41%, and a mixture of 1,6- and 1,7-
dipyrrolidyl PDIs was also isolated in 25% total yield.
When a combination of PDC/AgNO3 was used for in situ
oxidation, the formation of dipyrrolidyl PDI 5b was greatly
Scheme 1. Amination of dioctyl PDI 1 without catalyst.
enhanced, and the yields reached 60% for the 1,6-isomer
and 22% for the 1,7-isomer. The monopyrrolidyl PDI 5a
The radical anion generated was highly sensitive to air, was obtained only in 15% yield in this case. However, the
and as a result the yield of the reaction varied greatly. reaction times were as long as 6 and 4 d, respectively.
Hence, the amination of the aromatic ring of PDI 1 through Surprisingly, the use of CuCl2 in the amination of PDI 1
in situ oxidation with various oxidizing agents was ex- with pyrrolidine yielded only a trace amount of dipyrrolidyl
plored. To our delight, pyrrolidination of dioctyl PDI 1 PDI 5b after overnight stirring at room temperature. It
with KMnO4/AgNO3 as the oxidant, as reported Verbeeck should also be noted that we have compared the NMR
et al.,[22] proceeded regioselectively to afford exclusively the spectra of the synthesized compounds with the spectra of
1,6-dipyrrolidinyl isomer 5b in 65% yield (Scheme 2). The those prepared by the traditional bromination–pyrrolidin-
yield and the substitution sites are in good agreement with ation method[17a,17b] and we have not observed perisubsti-
the results published by Rauch et al.[19b] However, in our tuted compounds, as described by Langhals.[19a]
case, the substitution occurred without CuII catalysis and
heating.
According to our observations, the reactivity of PDIs
with different amido substituents in amination reactions,
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which was also reported by Rauhe et al.,[19b] is mostly HMBC (gHMBC) spectra of 7a and 7b (see Supporting In-
guided by the solubility. Thus, a mixture of PDI 1 with formation, S24 and S28) show that the singlets of protons
piperidine produced only a trace amount of the product 8-H and 11-H at δ = 7.82 ppm (disubstituted compound 7b)
even after prolonged stirring at room or elevated tempera- and 8-H at 8.0 ppm (compound 7a) correlate to the C-9Ј
tures owing to the poor solubility of 1 in piperidine. In con- and C-10Ј carbonyl carbon atoms at δ = 169 and 168 ppm,
trast, the reaction of much more soluble PDI 1Ј with pyr- respectively. The latter two were identified by their cross-
rolidine or piperidine and KMnO4/AgNO3 proceeded peaks with the α-butoxy protons at δ = 4.33 ppm. Simulta-
smoothly toward the disubstituted products 5bЈ and 6bЈ. A neously, the doublet of 2-H and 5-H correlates to the carb-
complete set of reactions with KMnO4/AgNO3 and dif- onyl atoms of the imide cycle, which were in turn identified
ferent substrates and nucleophiles is shown in Table 1. The by their cross-peaks with the α-amido methylene group of
products were isolated by preparative TLC, and the yields the octyl tail.
are given relative to the starting materials 1 and 1Ј. It
should be noted that the removal of the residual PTCDA
from 1 and 1Ј is not an easy task owing to its poor solu-
bility, and the apparent yields might be affected by that.
Table 1. Reactions of PDIs.
Scheme 3. Regioselective amination of PMI diester.
The described reaction is truly unique as it offers regio-
directed substitution of perylene derivatives. The amination
of PMI diester 4 with piperidine as a nucleophile works
similarly and results in the formation of the mono- and di-
substituted PMI diester derivatives 8a and 8b in 64 and
31% yield, respectively. The regiospecificity of the substitu-
tion was also preserved in this case, as confirmed by NMR
spectroscopy analysis. The reaction of PMI diester 4 was
[a] Mixture of 1,6- and 1,7-dipyrrolidyl PDI. [b] Observed by TLC
screened under different conditions and with different oxi-
and confirmed by MS. Mostly starting material remained in the
dants, and the results are summarized in Table 2. Unlike the
reaction.
Table 2. PMI reactions and yield.
Amination of PMIs
We decided to screen the applicability of the reaction to
other perylene derivatives. To our surprise, the presence of
the imide cycle played a crucial role in the amination of
perylenes. The reactions of perylenetetracarboxylic ester 2
and perylene monoanhydride diester 3[18g] under similar re-
action condition failed to produce the desired products, and
mostly unreacted starting compounds were recovered.
The most interesting results were obtained for the
perylenemonoimide diester (PMI diester) 4, as shown in
Scheme 3. When 4 was subjected to pyrrolidination, the re-
action produced a mixture of mono- and dipyrrolidinated
products in 60 and 20% yield, respectively. However, most
surprisingly, the substitution occurred exclusively at the bay
7- and 12-positions of the aromatic ring, which are distant
from the imide cycle. This conclusion was unambiguously
[a] The major spot was identified as 7a by TLC. A trace amount
derived from the NMR spectroscopic data. The gradient of 7b also formed.
4
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Controlled Regioselective Amination of Peryleneimides
Figure 2. (a) Absorption profile for the progress of reaction of PMI diester 4 in pyrrolidine under an argon atmosphere (black dashes:
0 h, dark gray dots: 4 h, gray solid line: 20 h, gray dash dot dot: 21 h, dark gray dashes: 23 h, black solid line: vial opened). (b) Absorption
of unsubstituted 4 (solid black), monopyrrolidyl 7a (dot black), and dipyrroliydyl 7b (dash black) PMI diesters.
reaction with the PDI, this reaction proceeds much faster
Experimental Section
in the presence of CuCl2. Under copper catalysis, the reac-
General: All commercially available reagents and solvents were pur-
tion can either be stopped at a monosubstitution step or
chased either from Sigma–Aldrich or from VWR and used without
pushed further to the disubstituted product simply by
further purifications unless otherwise mentioned. The products
controlling the reaction time. On the other hand, in the
were purified either by column chromatography with silica gel 60
presence of PDC and AgNO3 under argon, the reaction
also led to the monosubstituted product 7a in good yield
and gave practically no disubstitution.
(Merck) mesh size 40–63 μm or by preparative TLC with neutral
aluminium oxide 60 F254 plates (Merck). The NMR spectra were
recorded with a Varian Mercury 300 MHz spectrometer with
tetramethylsilane (TMS) as the internal standard. HRMS measure-
ments were performed with a Waters LCT Premier XE ESI-TOF
bench-top mass spectrometer. Lock-mass correction (leucine
enkephalin as reference compound), centering, and calibration
were applied to the raw data to obtain accurate masses.
The absorption spectra for the reaction of PMI diester 4
and pyrrolidine under argon and the absorption spectra of
the products after the exposure of the reaction mixture to
ambient air are shown in Figure 2. The spectrum of the
intermediate is similar to that observed for the diimide radi-
cal anion intermediate (Figure 1) and shows a distinct ab-
sorption in the near-IR region. Therefore, we suggest that
the reaction also proceeds via a radical anion intermediate.
The process does not necessarily require a catalyst, at least
to obtain monosubstituted compounds (Table 2, Entry 3).
However, the catalyst is needed for the preparation of di-
substituted molecules in reasonable yields. The Cu-cata-
lyzed reaction did not show the anion radical species by
UV/Vis spectroscopy, most probably because of their fast
oxidation upon formation.[19b] Silver nitrate alone may also
serve as a catalyst for the amination. The results of the
amination of PMI diester 4 are shown in Table 2.
General Procedure for the Direct Amination of Peryleneimides: Sil-
ver nitrate (1–10 equiv.) was added to a stirred solution of perylene-
imide (1 equiv.) in the amine (1.5–5 mL), and the mixture was
stirred for 10 min. Powdered KMnO4 (1–10 equiv.) was added to
this reaction mixture in portions over a period of 30 min, and stir-
ring was continued for another 16 h. On completion, the reaction
mixture was concentrated under reduced pressure, and the residue
was dissolved in chloroform (20 mL). The organic phase was
washed with water (2ϫ 50 mL) and dried with Na2SO4, and the
solvents were evaporated. The crude product was purified by TLC
(neutral aluminum oxide 60 F254 TLC plates with dichloromethane
as eluent) to yield the pure compound.
2,9-Dioctylisoquinolino[4Ј,5Ј,6Ј:6,5,10]anthra[2,1,9-def]isoquinoline-
1,3,8,10(2H,9H)-tetrone (1) and 2,9-Bis(2,5-di-tert-butylphenyl)-
isoquinolino[4Ј,5Ј,6Ј:6,5,10]anthra[2,1,9-def]isoquinoline-
1,3,8,10(2H,9H)-tetrone (1Ј): Compounds 1 and 1Ј were prepared
from perylenetetracarboxylic anhydride (PTCDA) according to the
literature procedure described by Langhals.[20]
Conclusions
We have found that the direct amination of perylene-
imides proceeds as a stepwise substitution via a perylene
radical anion and its subsequent oxidation. The substitu-
tion predominantly occurs regioselectively at the 1,6- and
7,12-positions of the bay region for perylenediimide and
perylenemonoimide diester, respectively. The imide cycle di-
rects the substitution to the distant position of the bay re-
gion; however, the presence of the imide is essential for the
reaction to occur. The substitution occurs as a one-pot re-
action with yields of 20–97% and can be controlled to pro-
duce selected products (mono or disubstituted perylenes) by
variation of the oxidant.
Tetrabutyl Perylene-3,4,9,10-tetracarboxylate (2) and Dibutyl 1,3-
Dioxo-1H,3H-benzo[5,10]anthra[2,1,9-def]isochromene-8,9-dicarb-
oxylate (3): These compounds were prepared from perylenetetra-
carboxylic anhydride (PTCDA) according to the procedure de-
scribed by Wang et al.[18g]
Dibutyl 2-Octyl-1,3-dioxo-2,3-dihydro-1H-benzo[5,10]anthra[2,1,9-
def]isoquinoline-8,9-dicarboxylate (4): A mixture of 3 (0.193 mmol,
101 mg), imidazole (1.0 g), and n-octylamine (1.15 mmol, 191 μL)
was stirred at 140 °C for 4 h. On completion, the reaction mixture
was cooled to 60 °C, and ethanol (5 mL) was added. The mixture
was neutralized by the dropwise addition of HCl (2 m) and ex-
tracted with toluene (three times). The organic phase was washed
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with water (twice), dried with Na2SO4, and concentrated. The
crude product was purified through silica gel with dichloromethane
as the eluent to yield 4 (83 mg, 68%) as a dark red solid. 1H NMR
(300 MHz, CDCl3, TMS): δ = 8.36–8.39 (d, J = 7.92 Hz, 2 H), 8.13
150.01, 149.95, 143.88, 143.86, 136.05, 136.03, 133.59, 133.56,
132.96, 132.93, 131.45, 130.93, 130.67, 128.87, 128.83, 128.73,
128.68, 127.79, 127.67, 126.19, 126.01, 123.34, 123.24, 118.08,
117.93, 117.36, 117.12, 52.21, 35.58, 35.56, 34.23, 31.86, 31.83,
(t, J = 8.50 Hz, 4 H), 7.95–7.97 (d, J = 7.92 Hz, 2 H), 4.36 (t, J = 31.25, 31.23, 29.69, 25.72 ppm. HRMS (ESI-TOF): calcd. for
6.74 Hz, 4 H), 4.16 (t, J = 7.62 Hz, 2 H), 1.67–1.94 (m, 6 H), 1.20–
1.64 (m, 15 H), 1.02 (t, J = 7.33 Hz, 6 H), 0.88 (s, 3 H) ppm. 13C
NMR (75 MHz, CDCl3, TMS): δ = 168.44, 163.58, 135.24, 132.04,
132.00, 131.27, 130.39, 129.24, 129.03, 128.99, 122.59, 125.83,
122.16, 121.77, 65.81, 56.56, 40.80, 32.08, 30.86, 29.60, 29.51,
28.37, 27.45, 22.89, 19.51, 14.36, 14.06, 9.60, 0.23 ppm. HRMS
(ESI-TOF): calcd. for C40H43NO6 [M]+ 633.3085; found 633.3068.
C60H64N4O4 [M]+ 904.4922; found 904.4949.
2,9-Bis(2,5-di-tert-butylphenyl)-5,13-di(piperidin-1-yl)isoquinolino-
[4Ј,5Ј,6Ј:6,5,10]anthra[2,1,9-def]isoquinoline-1,3,8,10(2H,9H)-tetrone
(6bЈ): The general procedure for the direct amination was followed
by stirring 1Ј (0.013 mmol, 10 mg), AgNO3 (0.13 mmol, 22 mg),
and powdered KMnO4 (0.13 mmol, 21 mg) in piperidine (1.5 mL)
for 24 h at room temperature to give 6bЈ (60%, 7.3 mg) as a dark
blue solid. 1H NMR (300 MHz, CDCl3, TMS): δ = 9.81 (d, J =
8.50 Hz, 2 H), 8.68 (d, J = 8.50 Hz, 2 H), 8.46 (s, 2 H), 7.62–7.59
(m, 2 H), 7.49–7.44 (m, 2 H), 7.02–6.98 (m, 2 H), 3.48–3.38 (m, 4
H), 2.98–2.87 (m, 4 H), 1.92–1.74 (m, 12 H), 1.35–1.32 (m, 36 H)
ppm. 13C NMR (75 MHz, CDCl3, TMS): δ = 164.80, 164.69,
153.45, 150.09, 150.01, 143.91, 143.82, 136.42, 136.39, 133.21,
132.74, 132.09, 131.17, 129.35, 128.77, 128.72, 128.30, 127.74,
127.58, 126.26, 126.15, 123.87, 123.57, 123.46, 122.86, 121.16,
120.58, 53.20, 53.08, 35.56, 34.25, 33.70, 31.93, 31.83, 31.25, 31.23,
30.16, 29.71, 29.37, 26.70, 25.87, 23.77, 22.70 ppm. HRMS (ESI-
TOF): calcd. for C62H68N4O4 [M]+ 932.5235; found 932.5287.
2,9-Dioctyl-5-(pyrrolidin-1-yl)isoquinolino[4Ј,5Ј,6Ј:6,5,10]anthra-
[2,1,9-def]isoquinoline-1,3,8,10(2H,9H)-tetrone (5a): Pyrrolidine
(20 mL) was bubbled with argon for 5 min, and 1 (0.0138 mmol,
8.5 mg) was added. The resultant mixture was again purged with
argon for 1 min and heated at 60 °C for 5 h. A pyridinium dichro-
mate solution (0.138 mmol, 5.3 mg dissolved in pyrrolidine and
purged with argon for 5 min) was added to the reaction mixture,
which was then stirred for 5 min. The reaction was quenched with
water (20 mL), extracted with chloroform (three times), dried with
Na2SO4, and concentrated. The crude product was purified by TLC
(neutral aluminum oxide 60 F254 TLC plates with dichloromethane
as eluent) to yield 5a as a green solid (7.2 mg, 70%). 1H NMR
(300 MHz, CDCl3, TMS): δ = 8.57–8.64 (m, 2 H), 8.29–8.49 (m, 4
H), 7.39–7.57 (m, 1 H), 4.09–4.31 (m, 4 H), 3.58–3.83 (m, 2 H),
2.74 (br s, 2 H), 1.88–2.23 (m, 4 H), 1.65–1.86 (m, 4 H), 1.23–1.52
(m, 21 H), 0.88 (t, J = 6.74 Hz, 6 H) ppm. 13C NMR (75 MHz,
CDCl3, TMS): δ = 163.87, 163.81, 163.71, 163.65, 148.40, 135.42,
135.18, 132.59, 130.95, 130.68, 128.93, 128.59, 127.11, 124.19,
126.56, 123.68, 122.98, 122.56, 122.33, 121.62, 120.41, 118.96,
115.83, 52.42, 40.67, 40.58, 31.86, 31.85, 29.42, 29.37, 29.28, 29.25,
28.18, 27.24, 27.18, 25.78, 22.66, 14.12 ppm. HRMS (ESI-TOF):
calcd. for C44H49N3O4 [M]+ 683.3718; found 683.3740.
Dibutyl 2-Octyl-1,3-dioxo-6-(pyrrolidin-1-yl)-2,3-dihydro-1H-benzo-
[5,10]anthra[2,1,9-def]isoquinoline-8,9-dicarboxylate (7a) and Di-
butyl 2-Octyl-1,3-dioxo-6,11-di(pyrrolidin-1-yl)-2,3-dihydro-1H-
benzo[5,10]anthra[2,1,9-def]isoquinoline-8,9-dicarboxylate (7b): The
general procedure for the direct amination was followed by stirring
4 (0.0946 mmol, 60 mg), AgNO3 (0.945 mmol, 160 mg), and pow-
dered KMnO4 (0.945 mmol, 150 mg) in pyrrolidine (1.5 mL) for
24 h at room temperature to give 7a (40 mg, 60%) and 7b (14.2 mg,
20%) as dark solids.
Data for 7a: 1H NMR (300 MHz, CDCl3, TMS): δ = 8.68–8.49 (m,
2 H), 8.46–8.27 (m, 2 H), 8.00 (s, 1 H), 7.95 (d, J = 8.05 Hz,1 H),
7.15 (d, J = 8.05 Hz, 1 H), 4.44–4.29 (m, 4 H), 4.26–4.16 (m, 2 H),
3.83–3.67 (m, 2 H), 3.67–3.61 (m, 2 H), 2.87–2.65 (m, 2 H), 2.18–
2.00 (m, 2 H), 2.00–1.88 (m, 2 H), 1.87–1.69 (m, 6 H), 1.60–1.39
(m, 8 H), 1.39–1.21 (m, 10 H), 1.02 (t, J = 7.24 Hz, 3 H), 0.98 (t,
J = 7.24 Hz, 3 H), 0.91–0.84 (m, 3 H) ppm. 13C NMR (75 MHz,
CDCl3, TMS): δ = 169.07, 168.10, 164.29, 164.16, 147.91, 136.52,
131.43, 131.26, 131.15, 131.02, 130.46, 129.26, 127.03, 126.17,
123.47, 122.69, 121.96, 120.73, 119.60, 117.58, 111.76, 70.77, 65.72,
65.66, 52.73, 40.68, 32.09, 30.92, 30.82, 29,92, 29.66, 29.50, 28.43,
27.48, 25.93, 22.89, 19.50, 19.48, 14.34, 14.06, 14.04 ppm. HRMS
(ESI-TOF): calcd. for C44H50N2O6 [M]+ 702.3663; found 702.3704.
2,9-Dioctyl-5,13-di(pyrrolidin-1-yl)isoquinolino[4Ј,5Ј,6Ј:6,5,10]-
anthra[2,1,9-def]isoquinoline-1,3,8,10(2H,9H)-tetrone (5b): The
compound was prepared by following the general procedure for the
direct amination of peryleneimides. Compound 1 (0.0325 mmol,
20 mg) was stirred with silver nitrate (0.0516 mmol, 8.7 mg) in pyr-
rolidine (5 mL). Powdered KMnO4 (0.0516 mmol, 8.2 mg) was
added to the reaction mixture, which was then stirred for 24 h to
afford 5b (65%, 15.8 mg) as a dark blue solid. 1H NMR (300 MHz,
CDCl3, TMS): δ = 8.68 (d, J = 7.92 Hz, 2 H), 8.34 (s, 2 H), 7.86
(d, J = 8.21 Hz, 2 H), 4.13–4.36 (m, 4 H), 3.56–3.91 (m, 4 H), 2.77
(br s, 3 H), 1.87–2.23 (m, 8 H), 1.67–1.86 (m, 4 H), 1.13–1.53 (m,
30 H), 0.87 (t, J = 6.74 Hz, 9 H) ppm. 13C NMR (75 MHz, CDCl3,
TMS): δ = 164.65, 164.35, 150.24, 135.94, 131.28, 130.45, 128.73,
128.47, 123.52, 123.11, 117.99, 117.80, 117.19, 117.10, 52.40, 40.87,
40.69, 32.09, 32.06, 29.93, 29.68, 29.59, 29.49, 29.46, 28.49, 28.44,
27.49, 27.38, 25.90, 22.89, 14.34 ppm. HRMS (ESI-TOF): calcd.
for C48H56N4O4 [M]+ 752.4296; found 752.4291.
1
Data for 7b: H NMR (300 MHz, CDCl3, TMS): δ = 8.65 (t, J =
7.92 Hz, 2 H), 7.83 (s, 2 H), 7.51 (t, J = 7.92 Hz, 2 H), 4.33 (t, J =
7.04 Hz, 4 H), 4.24 (t, J = 7.33 Hz, 2 H), 3.90–3.50 (m, 4 H), 3.02–
2.52 (m, 4 H), 1.84–1.71 (m, 6 H), 1.55–1.40 (m, 8 H), 0.99 (t, J =
7.33 Hz, 6 H), 0.93–0.79 (m, 3 H) ppm. 13C NMR (75 MHz,
CDCl3, TMS): δ = 168.65, 164.57, 149.95, 136.62, 132.95, 131.30,
130.34, 128.61, 128.46, 122.89, 116.45, 116.34, 115.89, 112.60,
65.63, 52.61, 40.61, 32.11, 30.88, 29.93, 29.70, 29.51, 28.52, 27.51,
25.97, 22.89, 19.49, 14.35, 14.07 ppm. HRMS (ESI-TOF): calcd.
for C48H57N3O6 [M]+ 771.4242; found 771.4203.
2,9-Bis(2,5-di-tert-butylphenyl)-5,13-di(pyrrolidin-1-yl)isoquinolino-
[4Ј,5Ј,6Ј:6,5,10]anthra[2,1,9-def]isoquinoline-1,3,8,10(2H,9H)-tetrone
(5bЈ): The general procedure for the direct amination was followed
by stirring 1Ј (0.026 mmol, 20 mg), AgNO3 (0.26 mmol, 44 mg),
and powdered KMnO4 (0.26 mmol, 41 mg) in pyrrolidine (3 mL)
for 24 h at room temperature to give 5bЈ (69%, 16.3 mg) as a dark
blue solid. 1H NMR (300 MHz, CDCl3, TMS): δ = 8.76 (d, J =
8.21 Hz, 2 H), 8.41 (s, 2 H), 7.92 (dd, J = 8.21 Hz, 2 H), 7.63–7.59
(m, 2 H), 7.49–7.44 (m, 2 H), 7.03–7.00 (m, 2 H), 3.77 (br, 3 H),
Dibutyl 2-Octyl-1,3-dioxo-6-(piperidin-1-yl)-2,3-dihydro-1H-benzo-
[5,10]anthra[2,1,9-def]isoquinoline-8,9-dicarboxylate (8a) and Di-
butyl 2-Octyl-1,3-dioxo-6,11-di(piperidin-1-yl)-2,3-dihydro-1H-
benzo[5,10]anthra[2,1,9-def]isoquinoline-8,9-dicarboxylate (8b): The
general procedure for the direct amination was followed by stirring
2.86 (br, 3 H), 2.05 (br, 8 H), 1.36–1.33 (m, 36 H) ppm. 13C NMR 4 (0.0.032 mmol, 20.5 mg), AgNO3 (0.32 mmol, 53 mg), and pow-
(75 MHz, CDCl3, TMS): δ = 165.38, 165.17, 150.08, 150.03, dered KMnO4 (0.32 mmol, 50 mg) in piperidine (3 mL) for 24 h at
6
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Controlled Regioselective Amination of Peryleneimides
1995, 34, 1323–1235; Angew. Chem. 1995, 107, 1487; c) F. O.
room temperature to give 8a (15 mg, 64%) and 8b (8 mg, 31%) as
Holtrup, G. R. J. Muller, H. Quante, S. De Feyter, F. C.
De Schryver, K. Mullen, Chem. Eur. J. 1997, 3, 219–225; d)
G. R. J. Muller, C. Meiners, V. Enkelmann, Y. Geerts, K.
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dark solids.
1
Data for 8a: H NMR (300 MHz, CDCl3, TMS): δ = 9.29 (d, J =
8.21 Hz, 2 H), 8.54–8.46 (m, 2 H), 8.29 (d, J = 7.92 Hz, 2 H), 8.00
(s, 1 H), 7.94 (d, J = 7.92 Hz, 1 H), 4.38–4.31 (m, 4 H), 4.22 (t, J
= 7.33 Hz, 2 H), 3.41–3.37 (m, 2 H), 2.97–2.89 (m, 2 H), 1.85–1.71
(m, 11 H), 1.57–1.25 (m, 20 H), 1.03–0.07 (m, 6 H), 0.90–0.85 (m,
3 H) ppm. 13C NMR (75 MHz, CDCl3, TMS): δ = 168.91, 168.32,
164.16, 163.83, 151.31, 137.11, 136.16, 131.90, 131.74, 131.71,
131.57, 131.53, 131.17, 129.26, 129.06, 127.71, 126.89, 124.44,
124.27, 123.53, 123.17, 121.39, 120.51, 119.82, 118.4, 65.75, 65.68,
52.80, 40.70, 32.08, 30.90, 30.80, 29.93, 29.63, 29.48, 28.42, 27.45,
25.93, 24.08, 22.88, 19.49, 14.33, 14.05 ppm. HRMS (ESI-TOF):
calcd. for C45H52N2O6Na [M + Na]+ 739.3718; found 739.3747.
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1
Data for 8b: H NMR (300 MHz, CDCl3, TMS): δ = 9.39 (d, J =
8.21 Hz, 2 H), 8.58 (d, J = 8.21 Hz, 2 H), 7.85 (s, 2 H), 4.34 (t, J
= 7.04 Hz, 4 H), 4.23 (t, J = 7.62 Hz, 2 H), 3.35–3.31 (m, 4 H),
2.90–2.82 (m, 4 H), 1.82–1.72 (m, 16 H), 1.51–1.43 (m, 7 H),1.28–
1.25 (m, 15 H), 1.01 (t, J = 7.33 Hz, 6 H), 0.90–0.85 (m, 4 H) ppm.
13C NMR (75 MHz, CDCl3, TMS): δ = 168.66, 164.15, 152.31,
137.36, 134.14, 131.66, 131.02, 129.02, 128.2, 123.12, 121.22,
119.77, 119.4, 119.06, 65.66, 53.06, 40.63, 32.09, 30.82, 29.92,
29.65, 29.48, 28.47, 27.48, 25.99, 24.16, 22.88, 19.47, 14.33, 14.03
ppm. HRMS (ESI-TOF): calcd. for C50H61N3O6 [M]+ 799.4555;
found 799.4553.
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The authors gratefully acknowledge the financial support from the
Academy of Finland.
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Received: October 13, 2014
Published Online: ᭿
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7

Job/Unit: O43299
/KAP1
Date: 11-12-14 11:37:53
Pages: 8
L. George, Z. Ahmed, H. Lemmetyinen, A. Efimov
FULL PAPER
Polycycles
L. George, Z. Ahmed, H. Lemmetyinen,
A. Efimov* ........................................ 1–8
Controlled Regioselective Amination of
Peryleneimides
Keywords: Amination / Perylenes / Poly-
cycles / Regioselectivity / Radical anions /
Imides
An efficient and direct protocol for the
highly regioselective amination of perylene-
imides has been developed. The method in-
volves the stepwise formation of a radical
anion, which is then oxidized in situ under
mild reaction conditions.
8
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