Synthesis of electroactive hydrazones derived from 3-(10-alkyl-10H- phenothiazin-3-yl)-2-propenals and their corresponding 3,3′-bispropenals

Article abstract of DOI:10.1016/j.tet.2012.03.010

3-(10-Alkyl-10H-phenothiazin-3-yl)-2-propenals and their corresponding 3,3′-bispropenals that represent a previously unexplored class of functionalised phenothiazine derivatives were prepared upon reacting N-alkylated 3-bromo- and 3,7-dibromo-10H-phenothiazines with acrolein diethyl acetal under Pd catalysis. The obtained heterocyclic 2,3-unsaturated aldehydes were condensed with N-methyl-N-phenylhydrazine and N,N-diphenylhydrazine resulting in mono- and dihydrazones that act as effective hole transporting materials. Thermal, optical, electrochemical and photophysical properties of the synthesised new organic electroactive derivatives have been investigated.

Full text of DOI:10.1016/j.tet.2012.03.010

Tetrahedron 68 (2012) 3552e3559
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of electroactive hydrazones derived from 3-(10-alkyl-10H-
0
phenothiazin-3-yl)-2-propenals and their corresponding 3,3 -bispropenals
a
b
b
b
Aurimas Bieliauskas , Vytas Martynaitis , Vytautas Getautis , Tadas Malinauskas , Vygintas
c
c
d
ꢀ
a,b,
*
Jankauskas , Egidijus Kamarauskas , Wolfgang Holzer , Algirdas Sa ꢀc kus
Institute of Synthetic Chemistry, Kaunas University of Technology, Radvil e_ n u˛ pl. 19, LT-50254 Kaunas, Lithuania
Department of Organic Chemistry, Faculty of Chemical Technology, Kaunas University of Technology, Radvil e_ n u˛ pl. 19, LT-50254 Kaunas, Lithuania
Department of Solid State Electronics, Vilnius University, Saul e_ tekio 9, LT-10222 Vilnius, Lithuania
Department of Drug and Natural Product Synthesis, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
a
b
c
d
a r t i c l e i n f o
a b s t r a c t
0
Article history:
3-(10-Alkyl-10H-phenothiazin-3-yl)-2-propenals and their corresponding 3,3 -bispropenals that repre-
sent a previously unexplored class of functionalised phenothiazine derivatives were prepared upon re-
acting N-alkylated 3-bromo- and 3,7-dibromo-10H-phenothiazines with acrolein diethyl acetal under Pd
catalysis. The obtained heterocyclic 2,3-unsaturated aldehydes were condensed with N-methyl-N-phe-
nylhydrazine and N,N-diphenylhydrazine resulting in mono- and dihydrazones that act as effective hole
transporting materials. Thermal, optical, electrochemical and photophysical properties of the synthesised
new organic electroactive derivatives have been investigated.
Received 4 December 2011
Received in revised form 18 February 2012
Accepted 5 March 2012
Available online 10 March 2012
Keywords:
Phenothiazine
Acrylaldehydes
Hydrazones
Ó 2012 Elsevier Ltd. All rights reserved.
Ionisation potentials
Charge transport
1
. Introduction
based on Jeffery’s11 phase-transfer reaction conditions [Pd(OAc)
n-Bu NOAc, K CO , KCl, DMF] and obtained (2E)-3-(quinolin-3-yl)-
2-propenal with yield of 79%. However, when 4-
2
,
4
2
3
2
,3-Unsaturated aromatic aldehydes are very important pre-
a
cursors in synthetic organic chemistry. For example, cinnamalde-
hyde and substituted derivatives were used as starting materials for
bromoisoquinoline and 3-bromobenzothiophene were used in
similar coupling reactions, the yields of the target aldehydes were
significantly reduced because of substantial dehalogenation of the
starting substrates. The reaction of heteroaryl bromides with
acrolein acetals in the presence of catalyst systems, such as
1
2
the synthesis of various carbocyclic and heterocyclic compounds,
3
including synthetic analogues of biomolecules. The reaction of
cinnamaldehydes with heterocycles bearing the CH-acidic methyl
4
group, afforded butadienyl dyes, while their condensation with
[PdCl(C
cyclopentane or [Pd(NH )
3
H
5
)]
2
/cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)
]/NaY zeolite afforded the corresponding
aromatic and heteroaromatic hydrazines gave the corresponding
hydrazones that were used as charge transporting materials for
photoreceptors.5
3 4
2,3-unsaturated heteroaryl aldehydes as the minor product in
12
a mixture with 3-(heteroaryl)propionic esters.
In recent years, efficient protocols have been developed for the
preparation of 2,3-unsaturated aromatic aldehydes using the Heck
In the present work, we report on the synthesis of 2,3-
unsaturated phenothiazinyl aldehydes by the Heck coupling
methodology and their further application for the preparation of
organic electronic materials. The phenothiazine ring system is
present in numerous examples of electroactive organic com-
6
7
reaction of arylhalides with propenal or its derivatives; the cor-
8
9
responding diethyl acetal, or 3,3-diacetoxypropene. These Pd-
catalysed coupling reactions were also applied to the synthesis of
7
f,8a,b,9,10,12b
13
several heterocyclic analogues of cinnamaldehyde.
Djakovitch and co-workers carried out the Heck arylation of
acrolein diethyl acetal with 3-bromoquinoline using conditions
pounds. However, few studies were devoted solely to the syn-
7
f
thesis and characterisation of phenothiazine-based, electroactive
14
hydrazones until now. Heteroaromatic hydrazones are effective
functional materials for the preparation of organic photoreceptors,
which are widely used on copying machine and laser printer
15
drums. The advantages of hydrazones against other classes of
*
Corresponding author. Tel.: þ370 37 451401; e-mail addresses: algirdas.sackus@
ꢀ
ktu.lt, asackus@yahoo.com (A. Sackus).
ꢀ
charge transporting materials include efficient charge transporting
0
040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2012.03.010

A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
3553
properties, a simple synthesis and a low cost of starting materi-
cycle,8a and a 10-alkylphenothiazine derivative due to dehaloge-
nation of the starting substrate. However, their presence in the
15b
7f
als.
Therefore, the condensation of 3-(phenothiazin-3-yl)-2-
propenals with N,N-disubstituted arylhydrazines could provide
easy access to new heterocyclic hydrazones bearing an extended
reaction mixture was only detected by methods, such as HPLC/MS
spectrometry and H NMR spectroscopy, and they were not isolated
1
and fully conjugated
p
-electron system for use as an efficient
in a pure state.
charge transporting material for organic photoreceptors.
The structures of the synthesised propenals, 4aed, were
1
13
confirmed by analysis of their spectroscopic data ( H NMR,
C
15
NMR, N NMR, IR, MS). For example, the IR spectrum of 4b
2
2
. Results and discussion
ꢀ1
showed a strong band at 1674 cm that was attributable to its
1
aldehydic C]O group. The H NMR spectrum contained a set of
.1. Synthesis
signals that was characteristic of the propenal moiety: a doublet
3
of the aldehyde proton at 9.63 ( J(CHO,H2)¼7.8 Hz), a doublet of
It is known that N-alkylated 3-bromo- and 3,7-dibromoph-
enothiazines and their corresponding iodo derivatives represent ex-
cellent substrates in various Pd-catalysed coupling reactions.
The most common methods used for the preparation of mono-
3
3
doublets of H-2 at 6.57 ( J(CHO,H2)¼7.8 Hz, J(H2,H3)¼15.8 Hz), and
3
a doublet of H-3 at 7.31 ppm ( J(H2,H3)¼15.8 Hz). E-Configuration
13c,d,16a,b
at the C]C double bond unequivocally follows from the mag-
nitude of the vicinal coupling between the alkene protons H-2
and H-3. NOE experiments (NOESY and NOE-difference) of
compound 4b revealed a strong through-space interaction be-
tween the aldehyde proton and proton H-3, but no interaction
between the aldehyde proton and H-2. This corresponds to the s-
brominated scaffolds involved the direct bromination of N-alkylphe-
nothiazines.1
3d,17
The alternative approach was based on the
bromination of N-unsubstituted phenothiazine followed by N-alkyl-
13c,16b
ation of the obtained brominated derivatives.
Treatment of N-
alkylphenothiazines with two equimolar amounts of bromine in acetic
trans conformation of the a,b-unsaturated aldehyde moiety. The
13c,16c,18
19
acid,
or dichloromethane resulted in the corresponding 3,7-
detailed assignments presented in Fig. 1 were based on the
combined application of standard NMR techniques including
COSY, TOCSY, HSQC, HMBC, NOE-difference and long-range INEPT
dibromo compounds.
In this work, the required 10-alkyl-3-bromophenothiazines 2aec
were synthesised from 10-alkylphenothiazines 1aec according to
20
spectra with selective excitation.
literature procedures.1
7b,c
10-(2-Ethylhexyl)-3-bromophenothiazine,
2
d, was obtained by bromination of 1d with NBS. This reaction was
carried out in the presence of a catalytic amount of benzoyl peroxide
in CCl , which allowed the target product to be obtained with a yield
of 60%. In contrast, the yield provided by the previously known syn-
7
.10
7.27
128.2
1
26.9
24.6
H 123.1
(
a)
4
7.31
1
9.63
193.5
127.4
thesis protocol,1 based on bromination of 1d with bromine in pyr-
idine, did not exceed 40%. The heating of 1a and 1b in CCl with two
equimolaramounts of NBS gave 10-alkyl-3,7-dibromophenothiazines
3e
6.94
H
H
H
4
H
S
123.1
-85.4
O
1
51.7
126.4
6.57
.32
17b
19
127.5
3
a
and 3b with good yields of 85% and 81%, respectively
H
H
H
15.3
N
(Scheme 1).
7.16
7
1
H C
2
H 114.8
H
1
28.4
6.88
CH3
6.84
147.5
.43
3
.94
S
S
Br
(ii)
S
(
i) for 2d
O
1
43.5 42.2
12.8
1
N
R
N
R
N
R
H
H
(
b)
4
a (50%)
S
N
1
a-d
2a-d
4b (63%)
4c (60%)
O
1
,2,4a R = Me, b R = Et, c R = Pr, d R = 2-ethylhexyl
4
d (62%)
H
(
i)
H
H
H
Br
S
Br
S
CH3
(
ii)
O
O
H
N
R
N
R
Fig. 1. (a) H NMR (italics), C NMR (plain) and 15N NMR (bold) chemical shifts [ppm;
1
13
3
a (R = Pr, 85%)
b (R = 2-ethylhexyl, 81%)
5a (R = Pr, 65%)
5b (R = 2-ethylhexyl, 60%)
1
13
15
3 2 3
ref. TMS ( H and C) and CH NO ( N)] for 4b in CDCl . (b) Relevant NOE correlations.
3
Scheme 1. Reagents and conditions: (i) NBS, CCl
4
, benzoyl peroxide, reflux, 2 h; (ii)
ꢁ
acrolein diethyl acetal, Pd(OAc) , n-Bu NOAc, K CO
2
4
2
3
, KCl, DMF, 90 C, 1.5 h.
The coupling reactions of 3,7-dibrominated phenothiazines 3a
and 3b with acrolein diethyl acetal, followed by hydrolysis, afforded
bispropenals 5a and 5b in satisfactory yields of 65% and 60%, re-
spectively. The H and C NMR spectra of bispropenal 5a displayed
only nine proton signals and twelve carbon signals, indicating that
the compound was a highly symmetrical molecule. The NOE ex-
Having successfully prepared the brominated scaffolds, we ex-
amined their ability to participate in Pd-catalysed couplings with
acrolein diethyl acetal. Thus, the Heck reaction of 3-bromo-10-
alkyl-10H-phenothiazines 2aed with acrolein diethyl acetal, car-
ried out under conditions optimised by Cacchi and co-workers for
the synthesis of 2,3-unsaturated aromatic aldehydes and fol-
lowing work-up of the formed adducts with hydrochloric acid,
afforded 3-(10-alkyl)-10H-3-phenothiazinyl-2-propenals 4aed.
These derivatives were isolated by column chromatography with
yields of 50e63%. The reaction also produced small amounts of by-
1
13
periments of 5a revealed an s-trans conformation for the both a,b-
unsaturated aldehyde moieties.
8
a
Condensation of propenals 4c, dwith 1-methyl-1-phenylhydrazine
and 1,1-diphenylhydrazine in toluene yielded hydrazones 6aed, while
a similar reaction of bispropenals 5a, b afforded dihydrazones 7aed
1
(Scheme 2). The H NMR spectra of compounds 6aed and 7aed
products
including
the
corresponding
ethyl
3-(10-
contained a characteristic doublet of one of the ethene protons in the
3
alkylphenothiazin-3-yl)propanoates that were formed due to hy-
drogen shifts in the carbopalladated intermediate of the catalytic
region of 6.36e6.64 ppm with vicinal J¼15.3e15.9 Hz. This unique
signal pattern verified the trans configuration of the ethene moiety.

3554
A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
R1
N
2-nd heating
N
1
S
PhR NNH
2
4
c,d
6a (R = Pr, R1 = Me, 66%)
toluene, Δ
N
R
1
1-st heating
6
6
6
b (R = Pr, R = Ph, 80%)
1
c (R = 2-ethylhexyl, R = Me, 80%)
1
d (R = 2-ethylhexyl, R = Ph, 73%)
R1
R1
N
1
PhR NNH
2
N
5
a,b
N
N
(a)
S
2
0
40 60 80 100 120 140 160 180 200 220
toluene, Δ
Temperature (°C)
7
7
7
7
a (R = Pr, R1 = Me, 55%)
N
R
b (R = Pr, R1 = Ph, 75%)
1
c (R = 2-ethylhexyl, R = Me, 70%)
1
2-nd heating
d (R = 2-ethylhexyl, R = Ph, 70%)
Scheme 2. Synthesis of hydrazones 6aed and 7aed.
1
-st heating
2
.2. Thermal analysis
The favourable state for hydrazones that are used as charge
transporters is a glassy state. The formation of the glassy state of
synthesised monohydrazones 6aed and dihydrazones 7aed was
confirmed by differential scanning calorimetry (DSC) analysis. The
melting points (T ) and glass transition temperatures (T ) of in-
m g
vestigated compounds are presented in Table 1.
(
b)
2
0
40 60 80 100 120 140 160 180 200 220
Temperature (°C)
ꢁ
Fig. 2. (a) DSC curves for 7c, (b) DSC curves for 7d (heating rate 10 C/min).
bathochromically for approximately 20 nm, and the maxima are in
the region of 400e420 nm. The shoulders in the absorption spectra
of dihydrazones are transformed into the absorption bands with
maxima at 350 nm and 400e420 nm of equal intensity.
Table 1
Data of thermal analysis and ionisation potentials (I
p
) of hydrazones 6aed and 7aed
ꢁ
ꢁ
Compound
T
m
,
C
T
g
,
C
p
I , eV
6
6
6
6
7
7
7
7
a
b
c
d
a
b
c
173
no
no
no
226
no
41
55
46
no
no
106
72
56
5.25
5.28
5.35
5.30
5.15
5.12
5.18
5.22
0.7
0.6
6a
6b
6c
154
no
6d
7a
0.5
d
7b
7c
7d
no e not observed.
0.4
0
0
0
0
.3
.2
.1
.0
These investigations revealed that some of the hydrazones can
exist both in crystalline and amorphous states, while others were
found only in an amorphous phase in our experiments. Thus, dur-
ing the first heating of dihydrazone 7c, the melting point was ob-
(a)
ꢁ
served at 154 C (Fig. 2a). No crystallisation was observed during
200
250
300
350
400
450
500
the second heating, and the only detected glass transition occurred
at 72 C. Glass transition occurs at 56 C for 7d, but no melting was
observed (Fig. 2b). This indicates that the original state of sample
Wavelength, nm
ꢁ
ꢁ
1
.0
.9
0
6a
6b
7
d was amorphous.
6
6
7
7
c
d
a
b
Comparison of the DSC analysis results for 6aed and 7aed
0.8
0.7
revealed a significant influence of the molecular mass (weight) on the
thermal transition data. In general, glass transition temperatures were
higher for the dihydrazones, compared with the monohydrazone
analogues. These data suggest that introduction of branched aliphatic
7c
7d
0
0
0
0
0
0
0
.6
.5
.4
.3
.2
.1
.0
g
chains potentially leads to a decreased in T in dihydrazone case.
2
.3. Optical, electrochemical and photophysical properties
The UVevis absorption spectra of hydrazones 6aed and 7aed
were recorded at room temperature in THF (Fig. 3a). The lowest
energy absorption bands of monohydrazones 6aed give maxima in
the region of 380e450 nm and a shoulder around 350 nm. The
lowest energy absorption band of dihydrazones 7aed is shifted
(b)
4
00
450
500
550
600
650
700
Wavelength, nm
Fig. 3. (a) UVevis absorption spectra of hydrazones 6aed and 7aed, (b) Fluorescence
spectra of hydrazones 6aed and 7aed.

A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
3555
The fluorescence spectra of hydrazones 6aed and 7aed are
provided in Fig. 3b. Emission maxima of monohydrazones 6aed are
in the region of 495e500 nm, and dihydrazones 7aed emit at
The new phenothiazine-based hydrazones were used for charge
carrier mobility studies. The xerographic time-of-flight (XTOF)
2
2
technique was used to characterise the magnitude of the hole-
drift mobility for the neat materials. In cases when measurements
were impossible due to crystallisation or other irregular layer for-
mations (6a, c and 7a), these materials were dispersed in bisphenol
Z polycarbonate as a polymer host (PC-Z).
5
20e525 nm. The small differences between the maxima of ab-
sorption and fluorescence spectra (w20 nm) of monohydrazones
and dihydrazones are attributable to the ‘butterfly’ shape of the
21
phenothiazine heterocycle and comparing weak conjugation
between two branches of hydrazone moieties in these molecules.
The EHOMO and ELUMO energies of the representative hydrazones
In all the cases investigated, the mobility (m) is approximated by
the formula
6
a, d, 7a, d and the reference compound 1c were measured
p
ffiffi
a
E
employing the cyclic voltammetry (CV) technique (Table 2). These
values do not represent any absolute solid-state or gas-phase ion-
ization energies, but can be used to compare different compounds
relative to one another. The cyclic voltammograms of all synthe-
sized compounds show quasi-reversible oxidation couples. Cyclic
voltammograms of investigated compounds are shown in the
m
¼
m
0e
(1)
where
m
0
is the zero field mobility,
E is electric field strength.
The mobility defining parameters
mobility values at the 10 V/cm field strength are given in Table 3.
Room temperature hole-drift mobilities were found to exceed
a
is PooleFrenkel parameter and
0
m and a values as well as the
6
(Fig. 4). Compared with phenothiazine 1c, addition of one hydra-
ꢀ
4
2
10
cm /V s in strong electric fields for neat materials, and for
zone fragment increases EHOMO by 0.1 eV in the case of N-methyl-N-
phenyl hydrazone 6a, while substitution of the methyl group by
a phenyl ring in 6d diminishes this effect, and EHOMO increases only
by 0.04 eV. Addition of a second hydrazone fragment in 7a, d in-
creases EHOMO by another 0.06 eV. Addition of hydrazone fragments
also narrows the energy bandgap and reduces ELUMO. Compared
with 1c addition of two hydrazone fragments lowers ELUMO by
w0.8 eV.
compounds with polymeric binder this parameter was found to be
two orders of magnitude lower. The examples of the dU/dt tran-
sients for the corresponding PC-Z blends are shown in Fig. 5.
XTOF measurements reveal that small charge transport tran-
sients are within a well-defined transit time on linear plots in the
case of 7a composition with PC-Z (Fig. 6a). The XTOF transients for
all the other samples were of disperse character, but the transit
time was well observed on lgelg plots (Fig. 6b).
Table 2
a
Electrochemical properties of 1c, 6a, d and 7a, d
HOMO, eVb
E
LUMO, eVc
E
opt, eVd
E
ox
vs Fc, Ve
E
ox
pa
vs Fc, V
E
1/2 vs Fc, Va
Eonset vs Fc, V
Compound
E
g
pc
1
6
6
7
7
c
ꢀ5.06
ꢀ4.96
ꢀ5.02
ꢀ4.90
ꢀ4.96
ꢀ1.52
ꢀ2.09
ꢀ2.20
ꢀ2.26
ꢀ2.31
3.54
2.87
2.82
2.64
2.65
0.33
0.22
0.27
0.13
0.20
0.18
0.09
0.16
0.05
0.12
0.26
0.16
0.22
0.09
0.16
0.18
0.08
0.15
0.03
0.09
a
d
a
d
a
The CV measurements were carried out at a glassy carbon electrode in dichloromethane solutions containing 0.1 M tetrabutylammonium hexafluorophosphate as
electrolyte and Ag/AgNO
3
as the reference electrode. Each measurement was calibrated with ferrocene (Fc).
b
Fc
E
HOMO ¼ ꢀ4:8 þ ðE1=2 ꢀ E1=2Þ.
c
opt
g
ELUMO ¼ EHOMO ꢀ E
.
d
e
opt
The optical band gaps E
g
estimated from the edges of electronic absorption spectra.
E1/2¼(EpaþEpc)/2; Epa and Epc are peak anodic and peak cathodic potentials, respectively.
3
. Conclusion
3
2
1
0
1
2
In conclusion, the coupling of 3-bromo- and 3,7-dibromo-10-
alkyl-10H-phenothiazines with acrolein diethyl acetal under Heck
reaction conditions afforded functionalised phenothiazine de-
rivatives possessing 2-propenal moieties as side chains with ac-
ceptable yields. Condensation of the latter with N,N-disubstituted
hydrazines gave the corresponding mono- and dihydrazones as
new effective organic electroactive materials. Additionally, their
ionisation potentials were measured by an electron photoemission
technique and were determined to be 5.12e5.35 eV, and their room
1
6
c
a
6d
a
d
7
7
-
-
ꢀ
4
2
temperature hole-drift mobilities exceeded 10 cm /V s in strong
electric fields for neat materials.
-
0.2 -0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
+
E vs Fc/Fc , V
4
4
. Experimental
Fig. 4. The cyclic voltammograms of compounds 1c, 6a, d and 7a, d.
.1. General
The photoelectron emission in the air spectra were recorded for
the investigated hydrazones and I values are presented in Table 1.
Namely due to the ‘butterfly’ effect, the ionisation potentials of
mono- and dihydrazones are similar and they are slightly lower for
dihydrazones 7aed (5.12e5.22 eV) compared to monohydrazones
The melting points were determined in open capillary tubes
p
with a Melt-Temp (Electrothermal) melting point apparatus and are
uncorrected. The DSC measurements were carried out on a Mettler
ꢁ
DSC 30 calorimeter at a scan rate of 10 C/min. Infrared spectra
were recorded on a Perkin Elmer Spectrum One spectrometer using
1
6
aed (5.25e5.35 eV).
potassium bromide pellets. H NMR spectra were recorded at

3556
A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
Table 3
Hole-drift mobility data for pure compounds and mixtures with PC-Z
(cm2
V
ꢀ1
s
ꢀ1
)a
m
(cm2
V
ꢀ1 ꢀ1
s
)b
a
(cm1/2
ꢀ1/2
V )
Transport
material,
d (
m
m)
m
0
host polymer
ac
7
w2.0ꢂ10
9.5ꢂ10
0.6ꢂ10
5.0ꢂ10
1.7ꢂ10
2.7ꢂ10
0.8ꢂ10
4.4ꢂ10
ꢀ6
5.5ꢂ10
1.6ꢂ10
5.4ꢂ10
1.3ꢂ10
4.6ꢂ10
2.4ꢂ10
1.3ꢂ10
9ꢂ10
ꢀ4
ꢀ5
ꢀ4
ꢀ5
ꢀ4
ꢀ6
ꢀ3
ꢀ4
ꢀ4
w0.0056
0.0051
0.0068
0.0056
0.0056
0.0045
0.0073
0.0053
0.0061
6
6
6
6
6
7
7
7
7
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
8
6
8
6
8
6
6
6
aþPC-Z, 1:1 10
b
3.6
5.5
3.2
6
3.8
3.7
5.1
cþPC-Z, 1:1
d
aþPC-Z, 1:3
b
c
d
1.9ꢂ10ꢀ
8ꢂ10
a
b
c
Mobility value at zero field strength.
Mobility value at 106 V cm field strength.
ꢀ1
Crystallisation at the perimeter of film started.
Fig. 6. (a) XTOF transients for 7a dispersed in PC-Z with a mass ratio of 1:3. The insert
shows one transient curve in a linear scale, where the transit time is marked by an
arrow. (b) XTOF transients in a double logarithmic scale for 7c. The arrow indicates the
hole transient time at the highest potential and the insert shows a typical transient
curve in a linear scale.
Fig. 5. Electric field dependencies of the hole-drift mobilities of hydrazones 6 and 7.
3
00 MHz on a Varian Unity Inova and at 500 MHz on a Bruker
4.1.3. Hole mobility measurements. The sample films for mobility
measurements were prepared by dissolving the compounds and
polycarbonate PC-Z (Iupilon Z-200 from Mitsubishi Gas Chemical
Co.) using mass ratio of 1:1 or 1:3 or neat in tetrahydrofuran and
thoroughly stirring the solution before casting the films. The
compounds dispersed in PC-Z were casted on polyester film with
conductive Al layer serving as the sample substrate. Smooth,
transparent and highly uniform films obtained indicated homoge-
neous dispersion of hydrazone molecules in the polymer host.
13
Avance 500 spectrometers; C NMR spectra were registered at 75
and 125 MHz, respectively. Chemical shifts, expressed in parts per
million, were relative to tetramethylsilane (TMS). 15N NMR spectra
(
50.69 MHz) were obtained on a Bruker Avance 500 spectrometer
using a ‘directly’ detecting broadband observe probe and were
referenced against neat, external nitromethane (coaxial capillary).
UVevis spectra were recorded on Perkin Elmer Lambda 35 UV/vis
spectrometer. Fluorescence spectra were recorded on Hitachi MPF-
2
0
4
spectrometer. Mass spectra were recorded on a Waters Micro-
mass ZQ instrument. Elemental analyses were measured with a CE-
40 elemental analyzer, Model 440 CHN/O/S. For thin layer chro-
matographic (TLC) analyses, Merck precoated TLC plates (silica gel
0 F254) were used. Starting 10-alkyl-10H-phenothiazines were
The hole-drift mobility was measured by XTOF technique.
Electric field was created by positive corona charging. The charge
carriers were generated at the layer surface by illumination with
pulses of nitrogen laser (pulse duration was 1 ns, wavelength
337 nm). The layer surface potential decrease as a result of pulse
illumination was up to 1e5% of initial potential before illumination.
The capacitance probe that was connected to the wide frequency
band electrometer measured the speed of the surface potential
4
6
synthesized by alkylation of 10H-phenothiazine with correspond-
ing alkylhalides in DMF applying sodium hydroxide as a base
according to a procedure outlined in the literature.
13d
t
decrease dU/dt. The transit time t was determined by the kink on
4
.1.1. Cyclic-voltammetry
studies were carried out by a three-electrode assembly cell from
Bio-Logic SAS and micro-AUTOLAB Type III potentios-
measurements. The
electrochemical
the curve of the dU/dt transient in linear or double logarithmic
2
scale. The drift mobility was calculated by the formula
m
0 t
¼d /U t ,
a
where d is the layer thickness, U e the surface potential at the
0
tategalvanostat. The measurements were carried out with a glassy
carbon electrode in dichloromethane solutions containing 0.1 M
tetrabutylammonium hexafluorophosphate as electrolyte, Ag/
moment of illumination.
4.1.4. Reagents. General chemicals were of the best grade available,
supplied by Aldrich Chemical Co. and were used without further
purification. Starting 10-alkyl-10H-phenothiazines were synthesized
by alkylation of 10H-phenothiazine with corresponding alkylhalides
in DMFapplying sodium hydroxide asa base according to a procedure
3
AgNO as the reference electrode and a Pt wire counter electrode.
4
.1.2. Ionization energy measurements. The ionization potentials
) of the sample films were estimated by performing electron
photoemission spectroscopy in air, as described in Ref. 18.
(I
p
13d
outlined in the literature. 10-Alkyl-3-bromophenothiazines 2aec

A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
3557
þ
were prepared from the corresponding 10-alkyl-10H-phenothiazines
according to the reported procedures.
z (%): 268 (MþH ). Anal. Calcd for C16
H13NOS: C, 71.88; H, 4.90; N,
17b,c
5.24. Found: C, 71.49; H, 5.00; N, 5.33.
4
.3.2. (E)-3-(10-Ethyl-10H-phenothiazin-3-yl)-2-propenal
4
.2. Synthetic procedures
ꢁ
1
(
4b). Yield 63%, yellow crystals, mp 104e106 C (from ethanol); H
NMR (500 MHz, CDCl ):
1.43 (3H, t, J¼7.0 Hz), 3.94 (2H, q,
J¼7.0 Hz), 6.57 (1H, dd, J¼15.8, 7.8 Hz), 6.84 (1H, d, J¼8.5 Hz), 6.88
1H, dd, J¼8.2,1.0 Hz), 6.94 (1H, dt, J¼7.5, 1.0 Hz), 7.10 (1H, dd, J¼7.5,
.5 Hz), 7.16 (1H, ddd, J¼8.2, 7.5, 1.5 Hz), 7.27 (1H, d, J¼2.1 Hz), 7.31
1H, d, J¼15.8 Hz), 7.32 (1H, dt, J¼8.5, 2.1 Hz), 9.63 (1H, d, J¼7.8 Hz);
3
d
4.2.1. General procedure for the bromination of 10-alkyl-10H-phe-
nothiazines (compounds 2d, 3a, b). A double-necked round bot-
tomed flask was charged with the appropriate 10-alkyl-10H-
phenothiazine (5 mmol) dissolved in boiling CCl (20 mL). Then
4
NBS (0.89 g, 5 mmol, for monobromination or 1.78 g, 10 mmol, for
dibromination) and benzoyl peroxide (48 mg, 0.2 mmol, for mon-
obromination or 96 mg, 0.4 mmol, for dibromination) were added
to the solution in 10 portions to the refluxing solution during 1 h
and the mixture was refluxed additionally for 1 h after the last
portion was added. Then the reaction mixture was washed with hot
(
1
(
1
3
3
C NMR (125 MHz, CDCl ): d 12.8, 42.2, 114.8, 115.3, 123.08, 123.11,
124.6, 126.4, 126.9, 127.4, 127.5, 128.2, 128.4, 143.5, 147.5, 151.7,
1
5
ꢀ1
193.5; N NMR (50 MHz, CDCl
3
):
d
296.4 (-85.4); IR (KBr, cm ):
n
þ
3
056, 2978, 2936, 2869, 1674; MS m/z (%): 282 (MþH , 100). Anal.
Calcd for C17H15NOS: C, 72.57; H, 5.37; N, 4.98. Found: C, 72.93; H,
5
.36; N, 4.90.
ꢁ
water (3ꢂ20 mL, 50 C), organic layer was dried over sodium sul-
fate and concentrated under reduced pressure. The residue was
purified by column chromatography on silica gel with hexane as
eluent.
4
.3.3. (2E)-3-(10-Propyl-10H-phenothiazin-3-yl)-2-propenal
1
(
4c). Yield 60%, yellow resinous substance; H NMR (500 MHz,
CDCl ): ), 1.80e1.84 (2H, m), 3.81 (2H, t,
1.01 (3H, t, J¼7.4 Hz, CH
J¼7.2 Hz), 6.55 (1H, dd, J¼15.9, 7.8 Hz), 6.82 (1H, d, J¼8.5 Hz), 6.85
3
d
3
4
.2.1.1. 3-Bromo-10-(2-ethylhexyl)-10H-phenothiazine
(
7
1H, d, J¼8.2 Hz), 6.94 (1H, t, J¼7.5 Hz), 7.10 (1H, dd, J¼7.6, 1.6 Hz),
1
(2d). Yield 1.17 g (60%), resinous substance. The H NMR spectrum
.15 (1H, m, J¼7.5, 8.2, 1.6 Hz), 7.26 (1H, d, J¼2.0 Hz), 7.29 (1H, dd,
13e
of 2d was in good agreement with that described in literature.
13
J¼15.9 Hz), 7.31 (1H, dd, J¼8.5, 2.0 Hz), 9.62 (1H, d, J¼7.8 Hz);
C
3
NMR (125 MHz, CDCl ): d 11.2, 19.9, 49.4, 115.2, 115.6, 123.1, 123.6,
4.2.1.2. 3,7-Dibromo-10-propyl-10H-phenothiazine (3a). Yield
125.1, 126.4, 127.0, 127.40, 127.42, 128.1, 128.3, 143.8, 147.8, 151.7,
ꢀ
1
1.69 g (85%), resinous substance; IR (KBr, cm ):
n
3060, 2963, 2930,
1
5
ꢀ1
1
3
2
4
93.4; N NMR (50 MHz, CDCl
3
):
d
293.8 (ꢀ88.0); IR (KBr, cm ):
n
1
2
3
872. H NMR (300 MHz, CDCl ): d
0.98 (3H, t, J¼7.5 Hz), 1.76 (2H,
057, 2963, 2931, 2872, 2817, 1673, 1618, 1596, 1573; MS m/z (%):
sex, J¼7.5 Hz), 3.71 (2H, t, J¼7.5 Hz), 6.65 (2H, d, J¼8.4 Hz),
þ
96 (MþH , 100). Anal. Calcd for C18
H17NOS: C, 73.19; H, 5.80; N,
13
7.19e7.23 (4H, m). The C NMR spectrum of 3a was in good
.74. Found: C, 73.15; H, 5.80; N, 4.77.
2
3
agreement with that described in literature.
4
.3.4. (2E)-3-[10-(2-Ethylhexyl)-10H-phenothiazin-3-yl]-2-propenal
4
.2.1.3. 3,7-Dibromo-10-(2-ethylhexyl)-10H-phenothiazine
1
(
(
1
7
4d). Yield 62%, deep orange resinous substance;
300 MHz, CDCl ): 0.83e0.90 (6H, m), 1.23e1.48 (8H, m),
.87e1.97 (1H, m), 3.76 (2H, d, J¼7.2 Hz), 6.57 (1H, dd, J¼15.9,
H NMR
1
13
(
3b). Yield 1.89 g (81%), resinous substance. The H and C spec-
3
d
trum of 3b was in good agreement with that described in
literature.19
.8 Hz), 6.85e6.98 (3H, m), 7.13e7.20 (2H, m), 7.29e7.36 (3H, m),
13
9
.63 (1H, d, J¼7.8 Hz); C NMR (75 MHz, CDCl
3
): d 10.4, 13.9, 23.0,
4
1
.3. General procedure for the preparation of 3-(10-alkyl-
0H-phenothiazin-3-yl)-2-propenals 4 and 5
23.9, 28.5, 30.5, 35.9, 51.2, 115.8, 116.3, 123.2, 124.7, 126.3, 126.5,
127.3, 127.4, 127.6, 128.18, 128.24, 144.4, 148.5, 151.7, 193.4. IR (KBr,
cm ): n 3057, 2963, 2931, 2872, 2817, 2733, 1674; MS m/z (%): 367
ꢀ1
þ
To a stirred solution of 10-alkyl-3-bromo-10H-phenothiazine
1.0 mmol) 2 in dry DMF (4 mL) under argon atmosphere acrolein
(MþH , 100). Anal. Calcd for C23
H27NOS: C, 75.57; H, 7.45; N, 3.83.
(
Found: C, 75.73; H, 7.68; N, 4.07.
diethyl acetal (0.458 mL, 3.0 mmol), tetrabutylammonium acetate
0.604 g, 2.0 mmol), potassium carbonate (0.208 g, 1.5 mmol), po-
tassium chloride (0.074 g, 1.0 mmol) and palladium (II) acetate
(
4.3.5. (E)-3-{7-[(E)-2-Formyl-1-ethenyl]-10-propyl-10H-phenothia-
ꢁ
zin-3-yl}-2-propenal (5a). Yield 65%, red crystals, mp 180e182
C
1
(
1
0.006 g, 0.03 mmol) were added and the mixture was stirred for
.5 h at 90 C. After cooling, 2 M hydrochloric acid was added slowly
(from ethanol); H NMR (500 MHz, CDCl
3
):
d
1.03 (3H, t, J¼7.4 Hz),
ꢁ
1.84 (2H, m), 3.85 (2H, t, J¼7.2 Hz), 6.57 (2H, dd, J¼15.8, 7.7 Hz), 6.85
(
to pH 4e5) and the reaction mixture was stirred at room tem-
perature for 10 min. Then, it was extracted with dichloromethane
3ꢂ8 mL), combined dichloromethane solution was washed with
(2H, d, J¼8.4 Hz), 7.34 (2H, dd, J¼8.4, 1.0 Hz), 7.27 (2H, d, J¼1.0 Hz),
13
7.31 (2H, d, J¼15.8 Hz), 9.64 (2H, d, J¼7.7 Hz); C NMR (125 MHz,
(
CDCl
3
): d 11.1, 20.0, 49.7, 115.6, 124.3, 127.0, 127.03, 128.4, 129.0,
15
water, dried over sodium sulfate and concentrated under reduced
pressure. The residue was purified by column chromatography on
silica gel with hexane/ethyl acetate (2/1 for 5a or 4/1 for 4aed, 5b).
Similar procedure was used to prepare bispropenals 5a and 5b
from 10-alkyl-3,7-dibromo-10H-phenothiazines 3a and 3b. The
only difference in the procedure is that the molar ratio of the re-
agents with 3a and 3b was increased twice.
146.4, 151.0, 193.2; N NMR (50 MHz, CDCl
(KBr, cm ):
m/z (%): 350 (MþH , 100). Anal. Calcd for C21
3
):
d
305.4 (ꢀ76.4); IR
ꢀ
1
n
3052, 3018, 2971, 2958, 2929, 2813, 2726, 1671; MS
þ
2
H19NO S: C, 72.18; H,
5.48; N, 4.01. Found: C, 72.38; H, 5.57; N, 4.11.
4.3.6. (E)-3-{10-(2-Ethylhexyl)-7-[(E)-2-formyl-1-ethenyl]-10H-phe-
nothiazin-3-yl}-2-propenal (5b). Yield 60% as a deep orange resin-
1
ous substance; H NMR (300 MHz, CDCl
3
):
d
0.82e0.91 (3H, m),
4
.3.1. (E)-3-(10-Methyl-10H-phenothiazin-3-yl)-2-propenal
0.87 (3H, t, J¼7.2 Hz), 1.20e1.45 (8H, m), 1.85e1.95 (1H, m), 3.78
ꢁ
1
(
4a). Yield 50%, orange crystals, mp 129e131 C (from ethanol); H
NMR (300 MHz, CDCl ):
3.40 (3H, s), 6.55 (1H, dd, J¼15.9, 7.8 Hz),
.79 (1H, d, J¼8.4 Hz), 6.83 (1H, dd, J¼8.4,1.2 Hz), 6.97 (1H, dt, J¼7.5,
.2 Hz), 7.11e7.22 (2H, m), 7.30e7.36 (3H, m), 9.63 (1H, d, J¼7.8 Hz);
(2H, d, J¼7.2 Hz), 6.57 (2H, dd, J¼15.9, 7.5 Hz), 6.90 (2H, d, J¼8.4 Hz),
1
3
3
d
7.30e7.38 (6H, m), 9.63 (2H, d, J¼7.5 Hz). C NMR (75 MHz, CDCl
3
):
6
d 10.4, 13.9, 22.9, 23.8, 28.4, 30.5, 36.1, 51.4, 116.3, 125.5, 127.0, 127.4,
128.3, 129.1, 147.2, 151.2, 193.3. IR (KBr, cm ):
ꢀ1
1
n
3051, 2957, 2925,
1
3
þ
C NMR (75 MHz, CDCl
3
):
d
35.6, 114.1, 114.5, 122.4, 123.2, 124.1,
2856, 2729, 1674. MS m/z (%): 420 (MþH , 100). Anal. Calcd for
126.5, 126.7, 127.2, 127.7, 128.3, 128.6, 144.5, 148.4, 151.7, 193.5; IR
26 2
C H29NO S: C, 74.43; H, 6.97; N, 3.34. Found: C, 73.95; H, 7.46;
ꢀ
1
(
KBr, cm ):
n
3047, 2965, 2899, 2819, 1667, 1616, 1592, 1570; MS m/
N, 3.28.

3558
A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
4
.4. General procedure for synthesis of hydrazones 6 and 7
The corresponding aldehyde 4 (or 5) (2 mmol) was dissolved in
115.9, 122.4 (4ꢂ C), 124.4 (2ꢂ C), 125.16, 125.22, 125.4, 125.9, 127.1,
1
27.6, 128.4, 129.4, 129.7 (4ꢂ C), 131.5, 133.0, 138.5, 143.5 (2ꢂ C),
ꢀ
1
145.25, 145.32. IR (KBr, cm ):
n
3059, 3037, 2956, 2924, 2854, 1589.
þ
toluene (2 mL) and the corresponding phenylhydrazine (3 mmol)
was added to the reaction mixture (6 mmol of hydrazine was used
with aldehyde 5). The reaction mixture was refluxed for 0.5e1.0 h
for preparing the 1,1-diphenylhydrazones, and it was refluxed for
MS m/z (%): 503 (MþH , 100). Anal. Calcd for C35
37 3
H N S: C, 79.05;
H, 7.01; N, 7.90. Found: C, 79.42; H, 6.91; N, 8.33.
4.4.5. (E)-3-{7-[(E)-2-Formyl-1-ethenyl]-10-propyl-10H-phenothiazin-
3-yl}-2-propenal di(1-methyl-1-phenylhydrazone) (7a). Bispropenal
5a (698 mg, 2 mmol) and 1-methyl-1-phenylhydrazine (733 mg,
6 mmol) were used to prepare 7a according to the general procedure
after refluxing for 5 h. Yield 1.229 g (55%), orange crystals, mp
2
e5 h for preparing the 1-phenyl-1-methylhydrazones. All hydra-
zones were purified by column chromatography on silica gel (elu-
ent for 6a, b, 7a-b: n-hexane/ethyl acetate 4:1 (v/v), eluent for 6c, d:
n-hexane/ethyl acetate 15:1 (v/v)). Solution was concentrated un-
der reduced pressure and the residue was vacuum dried.
ꢁ
1
3
224e226 C (from ethanol); H NMR (300 MHz, CDCl ): d 1.02 (3H, t,
J¼7.5 Hz), 1.78e1.90 (2H, m), 3.37 (6H, s), 3.80 (2H, t, J¼7.2 Hz), 6.59
4
.4.1. (E)-3-[10-Propyl-10H-phenothiazin-3-yl]-2-propenal 1-
(2H, d, J¼15.9 Hz), 6.62e7.32 (18H, m), 7.39 (2H, d, J¼9.0 Hz). NMR
methyl-1-phenylhydrazone (6a). Propenal 4c (590 mg, 2 mmol)
and 1-methyl-1-phenylhydrazine (366 mg, 3 mmol) were used to
prepare 6a according to the general procedure after refluxing for
(75 MHz, CDCl
3
):
d
11.2, 20.1, 33.4, 49.3, 115.3, 115.4 (4ꢂ C), 120.7,
124.2, 124.3, 125.0, 125.4, 126.0, 129.0 (4ꢂ C), 131.8, 135.1, 144.0,147.5.
ꢀ
1
IR (KBr, cm ):
n
3027, 2962, 2925, 2867, 1596, 1547, 1498, 1475. MS
þ
3
h. Product was crystallized from ethanol. Yield: 528 mg (66%),
m/z (%): 558 (MþH , 30). Anal. Calcd for C35
35 5
H N S: C, 75.37; H, 6.33;
ꢁ
1
yellow crystals, mp 171e173 C; H NMR (300 MHz, CDCl
3
):
d
1.01
N, 12.56. Found: C, 75.67; H, 6.33; N, 12.39.
(
(
3H, t, J¼7.5 Hz),1.83 (2H, m), 3.37 (3H, s), 3.81 (2H, t, J¼7.2 Hz), 6.60
13
1H, d, J¼15.9 Hz), 6.79e7.32 (13H, m), 7.50 (1H, d, J¼8.7 Hz).
):
11.3, 20.1, 33.6, 49.2, 115.4 (2ꢂ C), 115.5 (2ꢂ
C), 120.8, 122.4, 124.2, 125.0, 125.1, 125.5, 125.7, 127.2, 127.4, 129.0
C
4.4.6. (E)-3-{7-[(E)-2-Formyl-1-ethenyl]-10-propyl-10H-phenothia-
zin-3-yl}-2-propenal di(1,1-diphenylhydrazone) (7b). Bispropenal
5a (590 mg, 2 mmol) and 1,1-diphenylhydrazine hydrochloride
(1324 mg, 6 mmol) were used to prepare 7b according to the
general procedure after refluxing for 1 h. Yield 738 mg (75%),
NMR (75 MHz, CDCl
3
d
ꢀ
1
(
2
1
7
2ꢂ C), 131.6, 132.2, 135.6, 144.7, 144.8, 147.5. IR (KBr, cm ):
n
3026,
þ
957, 2923, 2869, 1596, 1571, 1500, 1457. MS m/z (%): 400 (MþH ,
ꢁ
1
00). Anal. Calcd for C25
25
H N
3
S: C, 75.15; H, 6.31; N, 10.52. Found: C,
deep yellow glassy substance; T
CDCl ):
g
106 C; H NMR (300 MHz,
1.01 (3H, t, J¼7.5 Hz), 1.81 (2H, sext, J¼7.5 Hz), 3.78 (2H,
5.24; H, 6.18; N, 10.49.
3
d
t, J¼7.5 Hz), 6.36 (2H, d, J¼14.7 Hz), 6.75 (2H, d, J¼9.0 Hz), 6.92
(2H, d, J¼9.3 Hz), 7.02 (4H, t, J¼9.0 Hz), 7.13e7.22 (14H, m),
4
.4.2. (E)-3-[10-Propyl-10H-phenothiazin-3-yl]-2-propenal 1,1-
13
diphenylhydrazone (6b). Propenal 4c (590 mg, 2 mmol) and 1,1-
diphenylhydrazine hydrochloride (662 mg, 3 mmol) were used to
prepare 6b according to the general procedure after refluxing for
3
7.39e7.45 (8H, m). C NMR (75 MHz, CDCl ): d 11.2, 20.0, 49.3,
115.2 (2ꢂ C), 122.4 (8ꢂ C), 124.2 (2ꢂ C), 124.4 (4ꢂ C), 125.0 (2ꢂ
C), 125.3 (2ꢂ C), 125.6 (2ꢂ C), 129.7 (8ꢂ C), 131.6 (2ꢂ C), 132.8
ꢁ
1
ꢀ1
0
.5 h. Yield 738 mg (80%), yellow resinous substance; T
NMR (300 MHz, CDCl ):
1.01 (3H, t, J¼7.5 Hz), 1.85 (2H, m), 3.80
2H, t, J¼7.5 Hz), 6.37 (1H, d, J¼15.3 Hz), 6.77e7.45 (19H, m). NMR
75 MHz, CDCl ):
11.2, 20.1, 49.3, 115.3, 115.4, 122.4 (4ꢂ C), 124.2,
24.5 (2ꢂ C), 124.9, 125.1, 125.6, 127.2, 127.4, 128.2, 129.0, 129.7 (4ꢂ
g
55 C; H
(2ꢂ C), 138.4 (2ꢂ C), 143.5 (4ꢂ C), 144.1 (2ꢂ C). IR (KBr, cm ):
n
þ
3
d
3035, 2960, 2927, 2869, 1587. MS m/z (%): 683 (MþH , 100). Anal.
(
(
1
Calcd for C45
39 5
H N S: C, 79.26; H, 5.76; N, 10.27. Found: C, 79.63;
3
d
H, 6.02; N, 10.21.
ꢀ1
C), 131.5, 133.1, 138.7, 143.5 (2ꢂ C), 144.68, 144.72. IR (KBr, cm ):
n
4.4.7. (E)-3-{10-(2-Ethylhexyl)-7-[(E)-2-formyl-1-ethenyl]-10H-pheno-
thiazin-3-yl}-2-propenal di(1-methyl-1-phenylhydrazone) (7c). Bispro-
penal 5b (839 mg, 2 mmol) and 1-methyl-1-phenylhydrazine
(733 mg, 6 mmol) were used to prepare 7c according to the general
procedure after refluxing for 4 h. Yield 879 mg (70%), light brown
3
(
035, 2961, 2929, 2869, 1588, 1574, 1494, 1463. MS m/z (%): 462
þ
MþH , 100). Anal. Calcd for C30
27 3
H N S: C, 78.06; H, 5.90; N, 9.10.
Found: C, 78.25; H, 5.85; N, 8.72.
ꢁ
1
4
1
.4.3. (E)-3-[10-(2-Ethylhexyl)-10H-phenothiazin-3-yl]-2-propenal
-methyl-1-phenylhydrazone (6c). Propenal 4d (731 mg, 2 mmol)
resinous substance; T 72 C; H NMR (300 MHz, CDCl ): d 0.9e0.95
g
3
(6H, m),1.29e1.54 (8H, m), 1.95e2.03 (1H, m), 3.40 (6H, s), 3.77 (2H, d,
J¼7.2 Hz), 6.64 (2H, d, J¼16.2 Hz), 6.86 (2H, d, J¼9.0 Hz), 6.96e7.06
and 1-methyl-1-phenylhydrazine (366 mg, 3 mmol) were used to
prepare 6c according to the general procedure after refluxing for
3
(4H, m), 7.26e7.44 (14H, m). NMR (75 MHz, CDCl ): d 10.5, 14.0, 23.0,
ꢁ
1
4
h. Yield 752 mg (80%), yellow resinous substance; T
NMR (300 MHz, CDCl ):
0.91 (6H, t, J¼7.5 Hz), 1.26e1.55 (8H, m),
.94e2.02 (1H, m), 3.37 (3H, s), 3.76 (2H, d, J¼7.5 Hz), 6.62 (1H, d,
g
46 C;
H
23.9, 28.5, 30.6, 33.2 (2ꢂ C), 36.0, 51.1, 115.3 (4ꢂ C), 115.9 (2ꢂ C), 120.6
3
d
(2ꢂ C),125.2 (2ꢂ C),125.3 (2ꢂ C),125.5 (2ꢂ C),126.1 (2ꢂ C),129.0 (4ꢂ
1
C), 131.7 (2ꢂ C), 131.9 (2ꢂ C), 134.9 (2ꢂ C), 144.7 (2ꢂ C), 147.6 (2ꢂ C).
13
ꢀ1
J¼15.9 Hz), 6.84e7.16 (5H, m), 7.21e7.42 (9H, m). C NMR (75 MHz,
CDCl ):
10.4, 14.0, 23.0, 23.9, 28.5, 30.6, 33.1, 35.7, 50.9, 115.2 (2ꢂ
C), 115.8, 120.5, 122.4, 125.2, 125.3, 125.88, 125.94, 127.1, 127.5, 129.0
IR (KBr, cm ):
n
3026, 2958, 2923, 2857, 1596. MS m/z (%): 629
þ
3
d
(MþH , 100). Anal. Calcd for C40
45 5
H N S: C, 76.52; H, 7.22; N, 11.15.
Found: C, 76.35; H, 7.47; N, 11.31.
ꢀ1
(
3
2ꢂ C), 131.67, 131.72, 134.8, 145.1, 145.3, 147.5. IR (KBr, cm ):
n
þ
058, 3034, 2955, 2923, 2854, 1597. MS m/z (%): 471 (MþH , 100).
4.4.8. (E)-3-{10-(2-Ethylhexyl)-7-[(E)-2-formyl-1-ethenyl]-10H-pheno-
thiazin-3-yl}-2-propenal di(1,1-diphenylhydrazone) (7d). Bispropenal
5b (839 mg, 2 mmol) and 1,1-diphenylhydrazine hydrochloride
Anal. Calcd for C30
H, 7.72; N, 8.76.
35 3
H N S: C, 76.72; H, 7.51; N, 8.95. Found: C, 77.13;
(1324 mg, 6 mmol) were used to prepare 7d according to the general
4
.4.4. (E)-3-[10-(2-Ethylhexyl)-10H-phenothiazin-3-yl]-2-propenal
procedure after refluxing for 2 h. Yield 1.052 g (70%), light brown
g 3
resinous substance; T 56 C; H NMR (300 MHz, CDCl ): d 0.85e0.90
ꢁ
1
1,1-diphenylhydrazone (6d). Propenal 4d (731 mg, 2 mmol) and 1,1-
diphenylhydrazine hydrochloride (662 mg, 3 mmol) were used to
(6H, m), 1.24e1.48 (8H, m), 1.86e1.99 (1H, m), 3.71 (2H, d, J¼7.2 Hz),
6.37 (2H, d, J¼15.3 Hz), 6.79 (2H, d, J¼9.0 Hz), 6.92e7.05 (4H, m),
prepare 6d according to the general procedure after refluxing for
1
.5 h. Yield 777 mg (73%), yellow resinous substance; 1H NMR
3
7.15e7.22 (16H, m), 7.40e7.45 (8H, m). NMR (75 MHz, CDCl ): d 10.4,
(
1
6
300 MHz, CDCl
3
):
d
0.85e0.90 (6H, m), 1.23e1.49 (8H, m),
14.0, 23.0, 23.9, 28.5, 30.6, 35.9, 51.1, 115.8 (2ꢂ C), 122.4 (8ꢂ C), 124.4
(4ꢂ C), 125.26 (2ꢂ C), 125.33 (2ꢂ C), 125.4 (2ꢂ C), 125.5 (2ꢂ C), 129.7
(8ꢂ C), 131.7 (2ꢂ C),132.8 (2ꢂ C),138.5 (2ꢂ C), 143.5 (4ꢂ C), 144.8 (2ꢂ
.90e1.98 (1H, m), 3.73 (2H, d, J¼6.9 Hz), 6.38 (1H, d, J¼15.9 Hz),
13
.79e7.05 (5H, m), 7.13e7.22 (10H, m), 7.40e7.45 (4H, m). C NMR
): 10.4, 14.0, 23.0, 23.9, 28.5, 30.6, 35.8, 51.0, 115.8,
ꢀ1
(
75 MHz, CDCl
3
d
C). IR (KBr, cm ): n 3036, 2956, 2924, 2855, 1588. MS m/z (%): 753

A. Bieliauskas et al. / Tetrahedron 68 (2012) 3552e3559
3559
þ
(
MþH , 100). Anal. Calcd for C50
49 5
H N S: C, 79.86; H, 6.57; N, 9.31.
8. (a) Battistuzzi, G.; Cacchi, S.; Fabrizi, G. Org. Lett. 2003, 5, 777; (b) Najera, C.;
Botella, L. Tetrahedron 2005, 61, 9688; (c) Pan, K.; No e_ l, S.; Pinel, C.; Djakovitch,
Found: C, 80.12; H, 6.91; N, 9.03.
L. J. Organomet. Chem. 2008, 693, 2863; (d) Alacid, E.; Nhjera, C. Eur. J. Org. Chem.
2
008, 18, 3102; (e) Djakovitch, L.; Pinel, C. Curr. Org. Synth. 2009, 6, 54; (f) No e_ l,
S.; Pinel, C.; Djakovitch, L. Org. Biomol. Chem. 2006, 4, 3760.
Acknowledgements
9
1
1
1
. Berthiol, F.; Doucet, H.; Santelli, M. Catal. Lett. 2005, 102, 281.
0. Kleizien e_ , N.; Arba ꢀc iauskien e_ , E.; Holzer, W.; Sackus, A. Molbank 2009, M644.
1. Jeffery, T. Tetrahedron Lett. 1994, 35, 4103.
2. (a) Lemhadri, M.; Doucet, H.; Santelli, M. Tetrahedron 2004, 60, 11533; (b) No e_ l,
ꢀ
ꢀ
This research was funded by the European Social Fund under the
Global Grant measure. Dr. habil. Valetas Gaidelis is thanked for the
help in the measurements of ionization potentials.
S.; Luo, C.; Pinel, C.; Djakovitch, L. Adv. Synth. Catal. 2007, 349, 1128.
13. For recent examples: (a) Wu, J. U.S. Patent 7,897,311, 2011; (b) Franz, A. W.;
Stoycheva, S.; Himmelhaus, M.; M u€ ller, T. J. J. Beilstein J. Org. Chem. 2010, 6,
doi:10.3762/bjoc.6.72; (c) Sailer, M; Franz, A. W.; M u€ ller, T. J. J. Chem.dEur.
References and notes
J. 2008, 14, 2602; (d) Park, M.-J.; Lee, J.; Park, J.-H.; Lee, S. K.; Lee, J.-I.; Chu,
H.-Y.; Hwang, D.-H.; Shim, H.-K. Macromolecules 2008, 41, 3063; (e) Vait-
keviciene, V.; Kruzinauskiene, A.; Grigalevicius, S.; Grazulevicius, J. V.;
Rutkaite, R.; Jankauskas, V. Synth. Met. 2008, 158, 383; (f) Qiu, X.; Lu, R.;
Zhou, H.; Zhang, X.; Xu, T.; Liu, X.; Zhao, Y. Tetrahedron Lett. 2007, 48,
1
. (a) Kano, T.; Tanaka, Y.; Maruoka, K. Org. Lett. 2006, 8, 2687; (b) Nagy, I.; Haj oꢁ s,
G.; Riedl, Z.; Egyed, O.; P aꢁ pai, I. Tetrahedron 2007, 63, 4730; (c) Brazier, J. B.;
Cavill, J. L.; Elliot, R. L.; Evans, G.; Gibbs, T. J. K.; Jones, I. L.; Platts, J. A.; Tom-
kinson, N. C. O. Tetrahedron 2009, 65, 9961; (d) Ma, Y.; Jin, S.; Kan, Y.; Zhang, Y.
J.; Zhang, W. Tetrahedron 2010, 66, 3849.
7
582; (g) Yang, L. Y.; Li, L. Q.; Wang, C.; Zhu, F. J.; Lu, Y.; Janietz, S.; Wedel,
A.; Hua, Y. L.; Yin, S. G. J. Lumin. 2007, 122/123, 714; (h) Choi, D. H.; Han,
K. I.; Chang, I.-H.; Choi, S.-H.; Zhang, X.-H.; Ahn, K.-H.; Lee, Y. K.; Jang, J.
Synth. Met. 2007, 157, 332.
4. (a) Simokaitiene, J.; Danilevicius, A.; Grigalevicius, S.; Grazulevicius, J. V.; Ge-
tautis, V.; Jankauskas, V. Synth. Met. 2006, 156, 926; (b) Danilevicius, A.; Os-
trauskaite, J.; Grazulevicius, J. V.; Gaidelis, V.; Jankauskas, V.; Tokarski, Z.;
Jubran, N.; Sidaravicius, J.; Grevys, S.; Dzena, A. J. Photochem. Photobiol., A 2004,
2
. For the recent examples: (a) Sridharan, V.; Perumal, P. T.; Avenda n~ o, C.;
Men eꢁ ndez, C. Tetrahedron 2007, 63, 4407; (b) Kumar, A.; Maurya, R. A. Tetra-
1
hedron 2008, 64, 3477; (c) Jiang, J.; Yu, J.; Sun, X.-X.; Rao, Q.-Q.; Gong, L.-Z.
Angew. Chem., Int. Ed. 2008, 47, 2458; (d) Cui, P.; Xu, L.; Shi, Z.; Gan, L. J. Org.
Chem. 2011, 76, 4210; (e) Zhou, Y.-Q.; Wang, N.-X.; Zhou, S.-B.; Huang, Z.; Cao, L.
J. Org. Chem. 2011, 76, 669.
1
63, 523.
5. (a) Weiss, D. S.; Abkowitz, M. Chem. Rev. 2010, 110, 479; (b) Lygaitis, R.; Getautis,
V.; Grazulevicius, V. J. Chem. Soc. Rev. 2008, 37, 770.
3
. (a) Huang, C.; Da, S.; Li, Y.; Li, Y. J. Nat. Prod. 1997, 60, 277; (b) Crimmins, M. T.;
Haley, M. W. Org. Lett. 2006, 8, 4223; (c) Hadden, M.; Nieuwenhuyzen, M.;
Osborne, D.; Stevenson, P. J.; Thomson, N.; Walker, A. D. Tetrahedron 2006, 62,
1
1
6. (a) Sailer, M.; Gropeanu, R.-A.; M u€ ller, T. J. J. J. Org. Chem. 2003, 68, 7509; (b) Lin,
H.-H.; Chang, C.-C. Dyes Pigm. 2009, 83, 230; (c) Doskocz, J.; Soloducho, J.; Cabaj,
J.; Lapkowski, M.; Golba, S.; Palewska, K. Electroanalysis 2007, 19, 1394; (d) Cho,
M. J.; Kim, J. Y.; Kim, J. H.; Lee, S. H.; Dalton, L. R.; Choi, D. H. Bull. Korean Chem.
Soc. 2005, 26, 77.
3
977.
ꢀ
ꢀ
ꢀ
_
_
4
. (a) Sackus, A.; Amankaviciene, V.; Degutyte, R. Chemija 1999, 10, 218; (b) Krieg,
R.; Eitner, A.; G u€ nther, W.; Sch u€ rer, C.; Lindenau, J.; Halbhuber, K.-J. J. Mol.
Histol. 2008, 39, 169; (c) Vedernikov, A. I.; Ushakov, E. N.; Kuz’mina, L. G.;
Churakov, A. V.; Strelenko, Y. A.; W o€ rner, M.; Braun, A. M.; Howard, J. A. K.;
Alfimov, M. V.; Gromov, S. P. J. Phys. Org. Chem. 2010, 23, 195; (d) Sergeeva, T. I.;
Gromov, S. P.; Vedernikov, A. I.; Kapichnikova, M. S.; Alfimov, M. V.; M o€ bius, D.;
1
7. (a) Bodea, C.; Terdic, M. Acad. Repub. Pop. Rom. Fil. Cluj. Stud. Cercet. Chim. 1962,
3, 81; (b) Biehl, E. R.; Daniel, T.; Reeves, P. C.; Lapis, S. J. Heterocycl. Chem. 1974,
1, 247; (c) Ebdrup, S. J. Chem. Soc., Perkin Trans. 1 1998, 1147; (d) Radu, C.;
Vlassa, M.; Silberg, I. A.; Sh o€ ke, M.; F €a rca s¸ , S. I.; Culea, M. Heterocycl. Commun.
997, 3, 317.
8. Turdean, R.; Bogdan, E.; Terec, A.; Petran, A.; Vlase, L.; Turcu, I.; Grosu, I. Cent.
Eur. J. Chem. 2009, 7, 111.
1
1
Zaitsev, S. Y. Colloids Surf., A 2005, 264, 207.
5
6
. Sakai, K.; Hashimoto, M.; Tsutsui, K. U.S. Patent 4,332,948, 1982; (b) Ando, O.;
Murayama, T.; Ono, H.; Suzuki, T. U.S. Patent 4,987,045, 1991; (c) Liu, J.-M.;
Shen, S.-Y.; Teng, K.-F. U.S. Patent 5,453,343, 1995.
. (a) Heck, R. F.; Nolley, J. P. J. Org. Chem. 1972, 37, 2320; (b) Jeffery, T. J. Chem. Soc.,
Chem. Commun. 1984, 1287; (c) Heck, R. F. Vinyl Substitution with Organo-
palladium Intermediates In; Trost, B. M., Fleming, I., Semmelhack, M. F., Eds. .
Comprehensive Organic Synthesis; Pergamon: Oxford, 1991; Vol. 4, pp 833e863.
1
1
1
9. Hwang, D.-H.; Kim, S.-K.; Park, M.-J.; Lee, J.-H.; Koo, B.-W.; Kang, I.-N.; Kim, S.-
H.; Zyung, T. Chem. Mater. 2004, 16, 1298.
0. Braun, S.; Kalinowski, H.-O.; Berger, S. 150 and More Basic NMR Experiments;
Wiley-VCH: Weinheim, 1998.
1. (a) Yang, L.; Feng, J.-K.; Ren, A.-M. J. Org. Chem. 2005, 70, 5987; (b) Kamtekar, K.
T.; Dahms, K.; Batsanov, A. S.; Jankus, V.; Vaughan, H. L.; Monkman, A. P.; Bryce,
M. R. J. Polym. Sci., Part A: Polym. Chem. 2011, 49, 1129.
2. Vaezi-Nejad, S. M. Int. J. Electron. 1987, 62, 361.
3. Jovanovic, M. J.; Biehl, E. R. Org. Magn. Reson. 1984, 22, 491.
2
7. (a) Unroe, M. R.; Reinhardt, B. A. Synthesis 1987, 981; (b) Kobayashi, S.; Ueda, T.;
2
Fukuyama, T. Synlett 2000, 883; (c) Linkelstein, B. L.; Benner, E. A.; Hendrixson,
M. C.; Kranis, K. T.; Rauh, J. J.; Sethuraman, M. R.; McCann, S. F. Bioorg. Med.
Chem. 2002, 10, 599; (d) Gupta, A. K.; Song, C. H.; Oh, C. H. Tetrahedron Lett.
2
2
2
6
004, 45, 4113; (e) Nejjar, A.; Pinel, C.; Djakovitch, L. Adv. Synth. Catal. 2003, 345,
12; (f) No e_ l, S.; Djakovitch, L.; Pinel, C. Tetrahedron Lett. 2006, 47, 3839.