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Gulakova et al.
Organics, 99.5%, extra dry, over molecular sieves, stabilized)
were commercial chemicals and used as such.
Earlier, it has been demonstrated that methyl derivaꢀ
tives of heterocyclic bases do not react with formylphenyꢀ
lazaꢀcrown ethers under basic conditions.12 This can be
explained by the presence of a strong donor (dialkylamino
group) in the paraꢀposition relative to the formyl substituꢀ
ent, which increases the electron density on the formyl C
atom and makes it inert to the nucleophilic addition of
the methyl group of the heterocycle. Nevertheless, this
condensation occurs successfully under the conditions
of acid catalysis. Heating of compound 1 with formylꢀ
phenylazaꢀ18ꢀcrownꢀ6 ether 2b and formylphenylꢀ
azadithiaꢀ15ꢀcrownꢀ5 ether 2c in acetic anhydride gave
the corresponding products; in the latter case, both
monoꢀ and bisstyrylphenanthrolines were obtained.
The starting reagents were recovered in both cases. The
condensation of compound 1 with ether 2b in the presꢀ
ence of HCl gave monostyrylphenanthroline 3b only
in 5% yield, the major product being bisstyrylphenanꢀ
throline 4b.
We also attempted the synthesis of styryl derivatives 3a
and 3d by heating the reagents in acetic anhydride. The
yield of product 3a was only 12% because of considerable
resinification of formylbenzodithiacrown ether 2a under
these reaction conditions. Bromostyrylphenanthroline 3d
was not obtained at all by acidꢀcatalyzed condensation of
compound 1 with 4ꢀbromobenzaldehyde 2d.
According to NMR data, the coupling constants of the
olefinic protons are about 16 Hz (Table 2); therefore,
monoꢀ and bisstyrylphenanthrolines 3 and 4 were obtained
in the form of transꢀisomers.
Baseꢀcatalyzed condensation of compound 1 with aromatic
aldehydes 2a and 2d (general procedure). A suspension of ButOK
(0.72 mmol) in DMF (4 mL) was slowly added dropwise under
argon to a stirred solution of neocuproine (1) (0.72 mmol) and
aldehyde 2a or 2d (0.65 mmol) in dry DMF (4 mL). The reacꢀ
tion mixture was kept at room temperature for 24 h and concenꢀ
trated in vacuo. The residue was dissolved in distilled water
(30 mL) and the product was extracted with chloroform (3×20 mL).
The extracts were combined and concentrated; the residue was
chromatographed on Al2O3 with benzene—ethanol (100 : 1) as
an eluent.
This procedure was used to obtain 2ꢀ[2ꢀ(2,3,5,6,8,9,11,12,
14,15ꢀdecahydrobenzo[1,7,10,16,4,13]tetraoxadithiacyclooctaꢀ
decinꢀ18ꢀyl)ethenyl]ꢀ9ꢀmethylꢀ1,10ꢀphenanthroline (3a), 2ꢀ[2ꢀ
(4ꢀbromophenyl)ethenyl)]ꢀ9ꢀmethylꢀ1,10ꢀphenanthroline (3d),
and 2,9ꢀbis[2ꢀ(4ꢀbromophenyl)ethenyl]ꢀ1,10ꢀphenanthroline
(4d). For the yields of the products, see Table 1. Their physicoꢀ
chemical characteristics are given in Tables 2 and 3.
Condensation of compound 1 with aldehyde 2a in the presence
of LDA. A solution of compound 1 (0.1 g, 0.48 mmol) in dry
THF (3 mL) was added dropwise under argon at 0 °C to a stirred
solution of LDA (0.053 g, 0.49 mmol) in dry THF (2 mL). The
mixture was kept at 0 °C for 1 h, whereupon a suspension of
aldehyde 2a (0.179 g, 0.48 mmol) in dry THF (5 mL) was added
dropwise. The reaction mixture was kept at 0 °C for 2 h and then
at room temperature for 18 h and diluted with distilled water
(20 mL). The product was extracted with dichloromethane
(3×20 mL). The organic extracts were combined and concenꢀ
trated in vacuo. The residue was dissolved in toluene (20 mL)
and pꢀtoluenesulfonic acid (0.05 g) was added. The resulting
solution was kept in a flask equipped with a Dean—Stark trap at
110 °C for 12 h, cooled to room temperature, and concentrated
in vacuo. The residue was chromatographed on Al2O3 (gradient
elution with C6H6—MeCN from 10 : 1 to 4 : 1). The yield of
compound 3a was 0.025 g (10%). For the yields of the products,
see Table 1. Their physicochemical characteristics are given in
Tables 2 and 3.
Acidꢀcatalyzed condensation of compound 1 with aromatic alꢀ
dehydes 2a—c (general procedure). A solution of aldehyde 2a—c
(0.54 mmol) and neocuproine (1) (0.54 mmol) in acetic anhyꢀ
dride (4 mL) was kept under argon at 140 °C for 6—10 h. The
reaction mixture was cooled and diluted with distilled water
(60 mL). The aqueous solution was neutralized with 15% NaOH
to pH 7—8 and the product was extracted with benzene (3×35 mL).
The organic extracts were combined and concentrated in vacuo.
The residue was chromatographed on Al2O3 (gradient elution
with C6H6—MeCN from 10 : 1 to 4 : 1). This procedure was
used to obtain 2ꢀ[2ꢀ(2,3,5,6,8,9,11, 12,14,15ꢀdecahydrobenzoꢀ
[1,7,10,16,4,13]tetraoxadithiacyclooctadecinꢀ18ꢀyl)ethenyl]ꢀ9ꢀ
methylꢀ1,10ꢀphenanthroline (3a), 2ꢀ{2ꢀ[4ꢀ(1,4ꢀdioxaꢀ7,13ꢀ
dithiaꢀ10ꢀazacyclopentadecanꢀ10ꢀyl)phenyl]ethenyl}ꢀ9ꢀmethylꢀ
1,10ꢀphenanthroline (3c), and 2,9ꢀbis{2ꢀ[4ꢀ(1,4ꢀdioxaꢀ7,13ꢀ
dithiaꢀ10ꢀazacyclopentadecanꢀ10ꢀyl)phenyl]ethenyl}ꢀ1,10ꢀ
phenanthroline (4c). For the yields of the products, see Table 1.
Their physicochemical characteristics are given in Tables 2 and 3.
Condensation of compound 1 with aldehyde 2b in the presence
of HCl. A solution of neocuproine (1) (150 mg, 0.72 mmol) and
HCl (0.1 mL) in ethanol (4 mL) was evaporated to dryness
in vacuo. Then the resulting neocuproine hydrochloride was
To sum up, we obtained for the first time crownꢀconꢀ
taining monoꢀ and bisstyrylphenanthrolines, potential reꢀ
ceptors that can selectively form stable complexes and
intensely absorb or emit light, which is peculiar to photoꢀ
sensitive groups. Although the yields of the target products
are low, the advantages of the methods we proposed for
their synthesis include accessible starting reagents, singleꢀ
step reactions without side processes, and simple purificaꢀ
tion of products.
Experimental
Melting points were measured on a MelꢀTemp instrument.
1H NMR spectra were recorded on a Bruker DRX300 spectromꢀ
eter (300.13 MHz) with Me4Si as the internal standard. Chemiꢀ
cal shifts and coupling constants were measured to within
0.01 ppm and 0.1 Hz, respectively. Elemental analysis was perꢀ
formed at the Microanalysis Laboratory of the A. N. Nesmeyꢀ
anov Institute of Organoelement Compounds (Russian Acadeꢀ
my of Sciences). Mass spectra were recorded on a Surveyor MSQ
instrument (Thermo Finnigan; Waters column, XBridge C18
2.5 um 3.0×20 mm). Column chromatography was carried out
on aluminum oxide (neutral, Brockmann activity I, STD grade,
150 mesh, 58 Å, Sigma—Aldrich).
Neocuproine (1), substituted benzaldehydes 2a—d, potasꢀ
sium tertꢀbutoxide, lithium diisopropylamide, THF (Acros
Gulakova
