Synthesis of alkylphenanthrenes from naphthylalkylidenemalonodinitriles. A route to 1-methyl-, 2-methyl-, and 1,2-dimethylphenanthrene

Article abstract of DOI:10.1016/S0040-4020(03)00884-6

The study has been carried out to evaluate the feasibility of synthesis of 1-methyl-, 2-methyl-, 1,2-dimethyl-, and 1-ethyl-2-methylphenanthrene through the annulation of the naphthalene system with the exploitation of the dicyanovinyl moiety of 2-naphthylalkylidenemalonodinitriles as an active electrophile in cold solutions of concentrated sulfuric acid. 2-(2-Naphthyl)propanal (3), 1-(2-naphthyl)propan-2-one (9), 3-(2-naphthyl)butan-2-one (14), and 3-(2-naphthyl)pentan-2-one (19) had been condensed with malonodinitrile to afford 2-naphthylalkylidenemalonodinitriles which were then cyclised to give 4-amino-1-methylphenanthrene-3-carbonitrile (5), 4-amino-2-methylphenanthrene-3-carbonitrile (11), 4-amino-1,2-dimethylphenanthrene-3-carbonitrile (16), and 4-amino-1-ethyl-2-metylphenanthrene-3-carbonitrile (21). The nitrile function has been removed from the aminonitriles, with the exception of 21, through hydrolysis and decarboxylation in alkaline ethanolic solutions under elevated pressure (～3 MPa) and temperature 220-230°C to give the respective 4-amino-methylphenanthrenes. Diazotisation of the phenanthreneamines and the reaction with hypophosphorus acid has lead to the methylphenanthrenes in moderate yields (50-52%).

Full text of DOI:10.1016/S0040-4020(03)00884-6

Tetrahedron 59 (2003) 5677–5683
Synthesis of alkylphenanthrenes from
naphthylalkylidenemalonodinitriles.
A route to 1-methyl-, 2-methyl-, and 1,2-dimethylphenanthrene
a
Wojciech Krasodomski, Michał K. Łuczynski, Jarosław Wilamowski and Janusz J. Sepioł
b
a
a
,
*
´
a
´
Department of Organic Chemistry, Jagiellonian University, Ingardena 3, PL-30-060 Krakow, Poland
´
Department of Chemistry, WM University, Plac Łodzki 4, PL-10-957 Olsztyn, Poland
b
Received 1 July 2002; revised 9 May 2003; accepted 5 June 2003
Abstract—The study has been carried out to evaluate the feasibility of synthesis of 1-methyl-, 2-methyl-, 1,2-dimethyl-, and 1-ethyl-2-
methylphenanthrene through the annulation of the naphthalene system with the exploitation of the dicyanovinyl moiety of
2-naphthylalkylidenemalonodinitriles as an active electrophile in cold solutions of concentrated sulfuric acid. 2-(2-Naphthyl)propanal
(3), 1-(2-naphthyl)propan-2-one (9), 3-(2-naphthyl)butan-2-one (14), and 3-(2-naphthyl)pentan-2-one (19) had been condensed with
malonodinitrile to afford 2-naphthylalkylidenemalonodinitriles which were then cyclised to give 4-amino-1-methylphenanthrene-3-
carbonitrile (5), 4-amino-2-methylphenanthrene-3-carbonitrile (11), 4-amino-1,2-dimethylphenanthrene-3-carbonitrile (16), and 4-amino-1-
ethyl-2-metylphenanthrene-3-carbonitrile (21). The nitrile function has been removed from the aminonitriles, with the exception of 21,
through hydrolysis and decarboxylation in alkaline ethanolic solutions under elevated pressure (,3 MPa) and temperature 220–2308C to
give the respective 4-amino-methylphenanthrenes. Diazotisation of the phenanthreneamines and the reaction with hypophosphorus acid has
lead to the methylphenanthrenes in moderate yields (50–52%).
q 2003 Elsevier Ltd. All rights reserved.
1. Introduction
course of cyclisations have also been encountered and
investigated to the limited extent.1,2 However, alkyl-
naphthalenes appear to be less important for the environ-
mental studies than alkylphenanthrenes. Therefore it was of
some interest to explore the extension of the aryl-alkylidene-
malonodinitrile approach for the synthesis of aromatic
systems possessing more than two condensed benzene rings.
As the importance of research related to the environmental
problems is steadily increasing worldwide, there is con-
tinuous demand to design new synthetic methods which
allow convenient and efficient preparation of reference
samples of organic pollutants present in the biosphere. In
connection with our environmental studies we were in need
of reference samples of methylphenanthrenes and other
alkylphenanthrenes. Herein we wish to report the results of
our studies aimed at finding out whether naphthylalkyl-
idenemalonodinitriles might be used as precursors in the
synthesis of several methylphenanthrenes, and potentially
other alkylphenanthrenes.
Methylphenanthrenes belong to an important group of
alkyl-aromatic hydrocarbons which are present in the
natural environment. Methylphenanthrenes arise through
the combustion of wood,3 coal,4 and are also emitted into
the environment by the internal combustion engines,5 in
particular by Diesel engines.6 These hydrocarbons are created
in a variety of geochemical processes,7 and their presence was
also detected in soil, water, river and sea sediments,8
sedimental rock,9 and in crude oil.10 Analysis of air, especially
of subtle dust suspended in polluted air, entails evaluation of
the total amount of phenanthrene derivatives, 1-methyl-
phenanthrene and also isomeric methylphenanthrenes.11
Phenyl- and tolyl-alkylidenemalonodinitriles have been
employed in the synthesis of some dimethylnaphthalenes
or their derivatives. The ‘ylidenemalonodinitrile route’
leading to these simple alkyl-aromatic hydrocarbons has
been preliminarily explored.1 The problems of regio-
selectivity in ring closure of tolyl-alkylidenemalonodi-
nitriles or rearrangement of carbon framework in the
There is a great variety of methods which are available for
the synthesis of phenanthrene and its derivatives.12 Perhaps
the most extensively investigated method is the classical
Haworth synthesis with its annulation of the naphthalene
rings by a four carbon unit, and a stepwise aromatisation of
the newly formed carbocyclic ring.13 This method might be
Keywords: alkylidenemalonodinitriles; cyclisation; aminonitriles;
polycyclic aromatic compounds; alkylphenanthrenes.
*
Corresponding author. Tel.: þ48-608380373; fax: þ48-126340515;
e-mail: sepiol@chemia.uj.edu.pl
0040–4020/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0040-4020(03)00884-6

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W. Krasodomski et al. / Tetrahedron 59 (2003) 5677–5683
employed for the convenient introduction of alkyl group
into the desired positions on the phenanthrene system. Other
synthetic methods which lead to the phenanthrenes involve
cyclisation of stilbenes,14 cycloaromatisation of a-oxo-
ketone dithioacetals,15 rearrangement of certain carbocyclic
spiranes,16 or PtCl2-catalysed cycloisomerisation of the
ortho-alkynylated biphenyls.17 This publication gives many
references to reviews and recent reports on the synthesis of
phenanthrenes which were published in the last years.
Synthesis of 1-methylphenanthrene from 2-acetyl-
naphthalene (1) is depicted in Scheme 1. 2-(2-Naphthyl)-
propanal (3) was obtained from ketone 1 through a modified
Darzen’s condensation with ethyl chloroacetate in the
presence of sodium hydride as a base.18 Glycidic esters 2
(60% yield) were hydrolysed and decarboxylated to
aldehyde 3 (70%). Condensation of 3 with malonodinitrile
gave dinitrile 4 (57%) which on dissolving in cold sulfuric
acid furnished aminonitrile 5 (50%). The aminonitrile was
decyanated to amine 6 (71%) on heating under pressure
(,3 MPa) with ethanolic sodium hydroxide solution.
Diazotisation of 6 and then the reduction of the diazonium
salt with hypophosphorous acid gave 1-methylphenanthrene
(47%). The synthetic sequence leading from 1 to the
known19 hydrocarbon 7 is also a proof of the structure of
aminonitrile 5 and amine 6. Reservations about structure of
aminonitrile 5 and in consequence of 6 and 7 are not
completely unfounded. Our recent investigation revealed
that some aryl-alkylidenemalonodinitriles might rearrange
on cyclisation in sulfuric acid.2 However, this was not the
case in the outlined above reaction sequence leading from 4
to 7.
2. Results and discussion
The approach reported here is a modification and extension
of our method designed earlier for the synthesis of some
dimethylnaphthalenes.1,2 An aromatic aldehyde is con-
verted to 1-arylpropan-2-one, usually through condensation
with nitroethane and the reduction of obtained nitroalkenes.
On the other hand 2-arylpropanals are synthesised from
acetyl arenes using the Darzen’s reaction. Condensation of
arylpropanones and arylpropanals with malonodinitrile
gives the dinitriles which are then cyclised to the
phenanthrene aminonitriles. In our present synthesis
cyclisation occurs in the a-position of the naphthalene
system. Sequential removal of the nitrile and the amino
groups from aminonitriles leads to methylphenanthrenes.
Employing naphthylpropanones and naphthylpropanals
allows the introduction of the methyl group in the 1- or
2-position of the phenanthrene system.
Ketone 9 was obtained in 61% yield from aldehyde 8
through condensation with nitroethane and then reduction of
the mixture of nitropropenes. This method was used earlier
for the preparation of tolylpropan-2-ones.1 Ketone 9
afforded the dinitrile 10 (57%). Cyclisation of 10 in sulfuric
acid gave aminonitrile 11 (60%) which was then decyanated
to amine 12 under the same condition as aminonitrile 5
Scheme 1. (i) ClCH2COOC2H5, NaH, CH3CN (60%); (ii) C2H5ONa, C2H5OH; (iii) 5% H2SO4 (70%); (iv) CH2(CN)2, CH3COOH, CH3COONH4, benzene
(57%); (v) H2SO4, 08C (50%); (vi) NaOH, C2H5OH, 2108C, 3 MPa (71%); (vii) NaNO2, HCl; 0–58C, (viii) H3PO2 (47%).
Scheme 2. (i) C2H5NO2, piperidine, toluene; (ii) Fe, HClaq, (61%); (iii) CH2(CN)2, CH3COOH, CH3COONH4, benzene (57%); (iv) H2SO4, 08C (60%);
(v) NaOH, C2H5OH, 2108C, 3 MPa (85%); (vi) NaNO2, HCl, 0–58C; (vii) H3PO2 (41%).

W. Krasodomski et al. / Tetrahedron 59 (2003) 5677–5683
5679
Scheme 3. (i) CH3I, NaOH, TEBA (59%); (ii) CH2(CN)2, CH3COOH, CH3COONH4, benzene (73%); (iii) H2SO4, 08C (74%); (iv) NaOH, C2H5OH, 2108C,
3 MPa (92%); (v) NaNO2, HCl, 0–58C; (vi) H3PO2 (53%).
(Scheme 2). The structure of aminonitrile 11 was confirmed
by spectroscopic measurements including HH COSY
experiment. Amine 12 (85%) was diazotised and reduced
in the presence of hypophosphorous acid to give known15
hydrocarbon 13 (41%). As in the case of 1-methyl-
phenanthrene, the synthetic pathway leading from aldehyde
8 to hydrocarbon 13 revealed that cyclisation of 10 to 11
occurred in the expected manner without the presence of
any rearranged aminonitrile, an isomer of 11.
ketone 9 with ethyl iodide under PTC conditions, low yields
of condensation of ketone 19 with malonodinitrile and of
cyclisation dinitrile 20 to aminonitrile 21, discouraged us
from completing the reaction sequence up to the preparation
of 1-ethyl-2-methyl-phenanthrene. The difficulty in the
introduction of ethyl group into the ‘1’ position of
phenanthrene aminonitrile 21 might be connected with
steric hindrance at all three stages of synthesis leading to 21.
Synthesis of 1,2-dimethylphenanthrene 18 was accom-
plished using ketone 9 as substrate (Scheme 3). Methylation
of 9 with methyl iodide gave butanone 14 (59%). The
following reaction sequence was similar to that presented in
Scheme 3. Condensation of 14 with malonodinitrile gave 15
(73%) which on dissolving in sulfuric acid was cyclised
smoothly to o-aminonitrile 16 (74%). Amine 17 was
obtained in good yield (92%) from aminonitrile 16.
Elimination of the amino group from 17 afforded hydro-
carbon 18 (53%).
3. Conclusion
The feasibility study presented in this report revealed that
cyclisation of several 2-naphthylalkylidene malonodinitriles
such as 4, 10, 15 or 20 might be smoothly accomplished in
the a position of naphthalene to give phenanthrene
aminonitriles in moderate yields (60–74%) in most cases.
Ring closure leading to these phenanthrene derivatives is
performed in a single step in sulfuric acid. Removal of the
nitrile function from the aminonitriles furnishes amino-
phenanthrenes 6, 12 or 17 in good yield (79–92%).
Elimination of the amino group from the obtained amines
leads in the final step to methylphenanthrenes 7, 13 or 18 in
relatively low yield (51–53%). A characteristic feature of
the synthetic approach presented here is the introduction of
the amino function in the ‘4’ position of phenanthrene.
Although this synthetic route has not been yet investigated,
the obtained aminophenanthrenes might be useful substrates
for the exchange of the amino function for other alkyl
groups. In this way a variety of alkylphenanthrenes
possessing a unique substitution pattern might be available
for potential environmental studies and other applications.
This last reaction sequence leading to 1,2-dimethyl-
naphthalene might potentially be used to introduce alkyl
groups of different sizes into ‘1’ and ‘2’ positions of
phenanthrene. This possibility was explored in the case of
1-ethyl-2-methylphenanthrene (Scheme 4). Alkylation of 9
with ethyl iodide gave pentanone 19 in poor 30% yield.
Condensation of 19 with malonodinitrile gave the dinitrile
20 (51%). Cyclisation of 20 in cold sulfuric acid afforded
aminonitrile 21 in low yield (25%). Low yield of alkylating
4. Experimental
4.1. General
IR spectra were recorded on a Bruker IFS 48 spectrometer.
1H and 13C NMR spectra were recorded on a Bruker AMX
500 spectrometer in the indicated solvent using TMS as
internal standard. Elemental analyses were performed using
an Euro EA 3000 instrument. Melting points were
determined on a Boetius hot-stage microscope and are
uncorrected.
Scheme 4. (i) CH3CH2I, NaOH, TEBA (30%); (ii) CH2(CN)2, CH3COOH,
CH3COONH4, benzene (51%); (iii) H2SO4, 08C (25%).

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W. Krasodomski et al. / Tetrahedron 59 (2003) 5677–5683
4.2. Synthesis of 1-methylphenanthrene (7) from
2-acetylnaphthalene (1)
at reflux for 4 h, the reaction progress was monitored by GC
and, if necessary, additional portions of malonodinitrile
(0.18 g, 2.7 mmol), ammonium acetate (0.21 g, 3 mmol)
and acetic acid (0.42 g, 7 mmol) were added and heating
was continued for the next 3–4 h. The solution was
successively washed with water, saturated aqueous sodium
hydrogen carbonate, water, and was dried over anhydrous
magnesium sulfate. Benzene was removed and the obtained
oil was distilled under reduced pressure or was purified by
column chromatography using silica gel and toluene as
eluent to give dinitriles 4, 10, 15 or 20. Solid dinitrile 10 was
recristallised from ethanol.
4.2.1. Ethyl 3-(2-naphthyl)-3-methyloxirane-2-car-
boxylate (2). In a 250 ml three-necked round-bottomed
flask equipped with an efficient mechanical stirrer, a reflux
condenser with protection from moisture and
a
thermometer, was placed dry acetonitrile (80 ml), 2-acethyl-
naphthalene (17.0 g, 0.10 mol) and ethyl chloroacetate
(13.5 g, 0.11 mol). A solution was preheated to 608C and
sodium hydride (5.3 g, 0.11 mol) as 50% suspension in
mineral oil was added in small portions over a period of 1 h
to the well stirred mixture while the temperature was
maintained at 60–658C. The mixture was then stirred and
heated for another 1 h. Acetonitrile was evaporated under
reduced pressure, water (50 ml) was carefully added and the
mixture was extracted with dichloromethane (3£100 ml).
The combined organic layers were dried over anhydrous
magnesium sulfate and the solvent was evaporated. The
obtained dark oil was distilled under reduced pressure to
give a cis/trans mixture (,1:1 ratio) of glycidic esters 2 as a
pale yellow oil; yield 15.4 g (60%); bp 126–1368C/300 Pa
(lit.20 175–1808C/700 Pa); IR (KBr) nmax (cm21) 3075,
2993, 2945, 1738, 1618, 1598, 1290, 1234, 1083, 860, 797,
784; dH (CDCl3) (a) 0.78 (t, 3H, J¼7.1 Hz), 1.81 (s, 3H),
3.55 (s, 1H), 3.83 (q, 2H, J¼7.1 Hz), 7.44–7.50 (m, 3H),
7.77–7.88 (m, 4H); (b) 1.33 (t, 3H, J¼7.1 Hz), 1.87 (s, 3H),
3.75 (s, 1H), 4.30 (q, 2H, J¼7.1 Hz), 7.44–7.50 (m, 3H),
7.77–7.88 (m, 4H); dC (CDCl3) 13.6, 14.2, 17.1, 24.6, 60.8,
60.9, 61.4, 61.4 62.0, 63.7, 122.7, 124.0, 124.6, 125.5,
126.1, 126.2, 126.3, 126.4, 127.6, 127.7, 127.9, 128.3,
132.7, 132.8, 132.9, 132.9, 134.6, 137.6, 167.0, 167.5.
4.3.1. 3-(2-Naphthyl)-but-1-en-1,1-dicarbonitrile (4).
Pale yellow oil; yield 3.3 g (57%); bp 132–1368C/20 Pa;
IR (neat) nmax (cm21) 3055, 2973, 2929, 2232, 1680, 1599;
dH (CDCl3) 1.65 (d, 3H, J¼7.9 Hz), 4.30 (m, 1H), 7.32–
7.96 (m, 8H); dC (CDCl3) 19.5, 38.0, 88.3, 110.6, 111.9,
123.9, 124.6, 125.9, 126.1, 126.8, 127.7, 129.4, 132.9,
133.6, 135.5, 171.2. Anal. found: C 82.51, H 5.17, N
12.41%; calcd for C16H12N2: C 82.73, H 5.21, N 12.06%.
4.4. General procedure for cyclisation of dinitriles 4, 10,
15 or 20 to 4-aminophenanthrene-3-carbonitriles
The oily dinitrile (10 mmol) was slowly dropped into
stirred, ice-cold concentrated sulfuric acid (20 ml). The
solid dinitrile 10 was added to sulfuric acid as a solution in
1.0 ml of acetone. The solution was kept in an ice-bath for
2 h and then was poured onto 300 g of crushed ice. The
resulting pale yellow precipitate was filtered off, washed
thoroughly with water, saturated aqueous sodium hydrogen
carbonate, and finally with water. The aminonitriles 5, 11,
16 or 21 were chromatographed on silica gel with toluene or
chloroform as eluent and recrystallised from an appropriate
solvent. Analytical samples were sublimed under reduced
pressure.
4.2.2. 2-(2-Naphthyl)propanal (3). The mixture of dia-
stereoisomeric glycidic esters 2 (15.0 g, 0.058 mol) was
slowly syringed into a well stirred cold solution of sodium
ethoxide. The solution was obtained by dissolving sodium
(1.33 g, 0.058 mol) in 30 ml of ethanol. Subsequently water
(1.0 ml) and diethyl ether (3.0 ml) were added. The mixture
was extracted with water (300 ml). The water layer was
acidified to pH¼1 with hydrochloric acid. The mixture was
gently heated for 30 min to complete the decarboxylation of
the glicydic acids and was then extracted with toluene
(3£30 ml). The combined extracts were dried over
anhydrous magnesium sulfate. Toluene was evaporated
and obtained oil was distilled under reduced pressure to give
7.5 g (70%) of 3 as an oil which solidified. Recrystallisation
from diethyl ether gave colourless crystals; mp 57–588C
(lit.20 mp 538C); bp 120–1268C/100 Pa; IR (KBr) nmax
(cm21) 3063, 2980, 2922, 2723, 1724, 1610, 1361, 815,
748; dH (CDCl3) 1.52 (d, 3H, J¼7.0 Hz), 3.78 (q, 1H,
J¼7.0 Hz), 7.28–7.86 (m, 7H), 9.74 (br. s, 1H); dC (CDCl3)
14.6, 53.0, 126.0, 126.1 126.4, 127.1, 127.7, 127.7, 128.8,
132.6, 133.6, 135.1, 200.9.
4.4.1. 4-Amino-1-methylphenanthrene-3-carbonitrile
(5). Pale yellow needles (from ethanol); yield 1.16 g
(50%); mp 131–1328C; IR (KBr) nmax (cm21) 3425,
3337, 3049, 2923, 2208, 1674, 1630, 1599; dH (CDCl3)
2.59 (s, 3H), 5.16 (s, 2H), 7.36 (s, 1H), 7.60–7.67 (m, 2H),
7.77–7.85 (m, 2H), 7.93 (d, 1H, J¼7.1 Hz), 9.12 (d, 1H,
J¼8.2 Hz); dC (CDCl3) 19.3, 94.2, 118.7, 119.1, 122.8,
125.1, 125.2, 126.4, 127.0, 128.4, 129.0, 130.1, 130.2,
132.6, 135.6, 148.0. Anal. found: C 82.81, H 5.34, N
12.12%; calcd for C16H12N2: C 82.73, H 5.21, N 12.06%.
4.5. General procedure for elimination of the nitrile
group from aminonitriles 5, 11 or 16. Synthesis of
phenanthrene amines 6, 12, and 17
Aminonitrile (1.5 mmol) and sodium hydroxide (1.0 g,
25 mmol) were dissolved in ethanol (100 ml). The
solution was heated in a 300 ml autoclave at 2408C
(,3.0 MPa) for 4 h. The mixture was diluted with water
(50 ml) and ethanol was removed on a rotary evaporator.
After cooling, the light brown precipitate was filtered off
and washed with water. Crude amines were purified by
column chromatography or TLC (SiO2/toluene), sublima-
tion under reduced pressure, and recrystallisation from an
appropriate solvent.
4.3. General procedure for condensation of aldehyde 3,
and ketones 9, 14, and 19 with malonodinitrile
In a 50 ml flask equipped with a Dean–Stark water
separator and a reflux condenser were placed acetic acid
(1.20 g, 20 mmol), ammonium acetate (0.62 g, 8 mmol),
malonodinitrile (1.78 g, 27 mmol), benzene (20 ml) and
aldehyde 3 or ketones 9, 14 or 19 (25 mmol). After heating

W. Krasodomski et al. / Tetrahedron 59 (2003) 5677–5683
5681
4.5.1. 4-Amino-1-methylphenanthrene (6). Light-brown
prisms (from hexane); yield 223 mg (71%); mp 114–1168C;
IR (KBr) nmax (cm21) 3454, 3374, 2926, 2846, 1619, 1595,
1415, 1325, 824, 746; dH (CDCl3) 2.65 (s, 3H), 4.13 (s, 2H),
6.93 (d, 1H, J¼7.7 Hz), 7.25–7.27 (m, 1H), 7.54–7.62 (m,
2H), 7.72 (d, 1H, J¼9.0 Hz), 7.87 (d, 1H, J¼9.1 Hz), 7.90
(d, 1H, J¼7.7 Hz), 9.32 (d, 1H, J¼7.7 Hz); dC (CDCl3)
19.6, 114.9, 120.1, 123.5, 125.5, 125.6, 125.8, 126.0, 126.9,
128.0, 128.5, 131.2, 132.5, 132.5, 143.3. Anal. found: C
87.11, H 6.04, N 6.52%; calcd for C15H13N: C 86.92, H
6.32, N 6.76%.
10 h and additional portions of nitroethane (4.8 g,
0.064 mol) and piperidine (1.4 ml) were added. After
heating at reflux for the next 10 h the solution was transfered
to a three-necked flask equipped with a reflux condenser, a
mechanical stirrer, a dropping funnel and a thermometer.
Iron dust (17 g, 0.304 mol) was added and the mixture was
preheated to 808C. Concentrated hydrochloric acid (30 ml)
was added dropwise to the solution over a period of 1 h and
the reaction was heated at 85–958C for the next 1 h. After
cooling, the mixture was distilled with steam. The distilate
was extracted with toluene (4£50 ml). The combined
organic layers were dried over anhydrous magnesium
sulfate and toluene was evaporated. The residual dark
oil was fractionated under reduced pressure to give ketone
9 which solidified to colourless crystals; yield 7.18 g
(61%); mp 35–378C (lit.21 mp 37–37.58C); IR (KBr) nmax
(cm21) 3055, 2923, 2854, 1711, 1509, 1361, 1164, 811,
753, 482; dH (CDCl3) 2.17 (s, 3H), 3.84 (s, 2H), 7.32–7.30
(m, 1H), 7.49–7.43 (m, 2H), 7.66 (s, 1H), 7.82–7.78 (m,
3H).
4.6. General procedure for elimination of the amino
function from phenanthrene amines 6, 12 or 17.
Synthesis of methylphenanthrenes 7, 13, and 18
The aminophenanthrene (0.95 mmol) was suspended in
7.0 ml of 50% hypophosphorous acid. The suspension was
cooled in an ice-bath and diazotised with sodium nitrite
(100 mg, 1.45 mmol) dissolved in a small amount of water.
The diazonium solution was left at þ58C for 48 h and the
mixture was then diluted with 20 ml of water. The solid
product was filtered off, washed with water and sublimed in
vacuo. Recrystallisation from ethanol gave colourless
crystals.
4.7.2. 3-(2-Naphthyl)-2-methylprop-1-en-1,1-dicarbo-
nitrile (10). Condensation of ketone 9 with malonodinitrile
was carried out according to the general procedure
described under Section 4.3. Pale yellow needles (from
ethanol); yield 3.3 g (57%); mp 144–1468C; IR (KBr) nmax
(cm21) 3049, 3011, 2942, 2226, 1599, 1509, 827, 761, 473;
dH (CDCl3) 2.20 (s, 3H), 4.02 (s, 2H), 7.30–7.25 (m, 1H),
7.55–7.49 (m, 2H), 7.67 (s, 1H), 7.86–7.81 (m, 3H); dC
(CDCl3) 22.2, 43.8, 86.5, 111.7, 112.0, 126.3, 126.5, 126.8,
127.6, 127.8, 128.0, 129.2, 131.7, 132.8, 133.5, 179.4. Anal.
found: C 82.70, H 5.31, N 11.98%; calcd for C16H12N2: C
82.73, H 5.21, N 12.06%.
4.6.1. 1-Methylphenanthrene (7). Yield 86 mg (47%); mp
120–1228C (lit.19 mp 122–122.58C); IR (KBr) nmax (cm21
)
3054, 3021, 1601, 822, 806, 745; dH (CDCl3) 2.73 (s, 3H),
7.45 (d, 1H, J¼6.3 Hz), 7.53–7.64 (m, 3H), 7.78 (d, 1H,
J¼8.8 Hz), 7.90 (d, 1H, J¼6.3 Hz), 7.96 (d, 1H, J¼8.9 Hz),
8.59 (d, 1H, J¼7.9 Hz), 8.70 (d, 1H, J¼7.8 Hz); dC (CDCl3)
19.9, 120.7, 122.9, 126.1, 126.4, 126.5, 126.7, 127.8, 128.5,
130.4, 130.7, 130.8, 131.7, 134.9.
4.7.3. 4-Amino-2-methylphenanthrene-3-carbonitrile
(11). Cyclisation of dinitrile 10 to aminonitrile 11 was
carried out according to the general procedure described
under Section 4.4. Pale yellow needles (from ethanol); yield
1.39 g (60%); mp 161–1628C; IR (KBr) nmax (cm21) 3431,
3356, 3249, 2923, 2201, 1657, 1616, 1402, 868, 811, 745,
613, 564, 531; dH (CDCl3) 2.56 (s, 3H), 5.23 (s, 2H), 7.06 (s,
1H), 7.47 (d, 1H, J¼8.7 Hz), 7.56 (dd, 1H, J¼7.8, 7.2 Hz),
7.62 (dd, 1H, J¼8.4, 7.2 Hz), 7.71 (d, 1H, J¼8.7 Hz), 7.87
4.7. Synthesis of 2-methylphenanthrene (13) from
2-naphthaldehyde (8)
4.7.1. 1-(2-Naphthyl)propan-2-one (9). In a 250 ml flask
equipped with a Dean–Stark water trap and a reflux
condenser were placed nitroethane (4.8 g, 0.064 mol),
piperidine (1.4 ml), 2-naphthaldehyde (10.0 g, 0.064 mol)
and toluene (50 ml). The mixture was heated at reflux for
1
Table 1. Correlations in H 1H COSY spectrum of 11
Chemical shift and coupling constant
Correlated signals
H3C
H2N
2.56 (s, 3H)
5.23 (s, 2H)
7.06 (s, 1H)
7.47 (d, 1H, J¼8.7 Hz)
7.56 (dd, 1H, J¼7.8, 7.2 Hz)
7.62 (dd, 1H, J¼8.4, 7.2 Hz)
7.71 (d, 1H, J¼8.7 Hz)
7.87 (d, 1H, J¼7.8 Hz)
8.93 (d, 1H, J¼8.4 Hz)
7.06 (s, 1H) HC-1
–
2.56 (s, 3H) H3C
7.71 (d, 1H, J¼8.7 Hz) HC-9
HC-1
HC-10
HC-7
HC-6
HC-9
HC-8
HC-5
7.87 (d, 1H, J¼7.8 Hz) HC-8; 7.62 (dd, 1H, J¼8.4, 7.2 Hz) HC-6
8.93 (d, 1H, J¼8.4 Hz) HC-5; 7.56 (dd, 1H, J¼7.8, 7.2 Hz) HC-7
7.47 (d, 1H, J¼8.7 Hz) HC-10
7.56 (dd, 1H, J¼7.8, 7.2 Hz) HC-7
7.62 (dd, 1H, J¼8.4, 7.2 Hz) HC-6

5682
W. Krasodomski et al. / Tetrahedron 59 (2003) 5677–5683
(d, 1H, J¼7.8 Hz), 8.93 (d, 1H, J¼8.4 Hz); dC (CDCl3)
20.7, 96.4, 116.4, 117.8, 119.6, 124.4, 126.0, 126.7, 127.1,
129.2, 130.0, 130.2, 132.6, 136.4, 137.6, 149.8. Anal. found:
C 82.89, H 5.43, N 11.98%; calcd for C16H12N2: C 82.73, H
5.21, N 12.06% (Table 1).
with malonodinitrile was carried out according to the
general procedure described under Section 4.3. Orange oil,
after chromatography; yield 1.35 g (73%); IR (KBr) nmax
(cm21) 3052, 2979, 2884, 2226, 1634, 1592, 1504, 948, 898,
856, 823, 756; dH (CDCl3) 1.63 (d, 3H, J¼7.1 Hz), 2.02 (s,
3H), 4.62 (q, 1H, J¼7.1 Hz), 7.27 (d, 1H, J¼8.5 Hz), 7.48
(t, 1H, J¼6.8 Hz), 7.51 (t, 1H, J¼6.9 Hz), 7.70 (s, 1H),
7.81–7.84 (m, 3H); dC (CDCl3) 16.6, 18.3, 45.3, 85.4,
111.8, 111.9, 125.1, 125.8, 126.4, 126.6, 127.6, 127.8,
128.8, 132.7, 133.3, 135.9, 184.0. Anal. found: C 82.78, H
5.72, N 11.44%; calcd for C17H14N2: C 82.93, H 5.69, N
11.38%.
4.7.4. 4-Amino-2-methylphenanthrene (12). Elimination
of the nitrile group from 11 was performed as described in
the general procedure under Section 4.5. Light brown
prisms (from ethanol); yield 264 mg (85%); mp 110–
1128C; IR (KBr) nmax (cm21) 3449, 3376, 2935, 2845, 1613,
1599, 1338, 824, 745; dH (CDCl3) 2.45 (s, 3H), 4.34 (s, 2H),
6.82 (s, 1H), 7.16 (s, 1H), 7.49–7.63 (m, 4H), 7.85 (d, 1H,
J¼7.8 Hz), 9.16 (d, 1H, J¼8.4 Hz); dC (CDCl3) 21.2, 117.0,
117.6, 120.3, 125.0, 125.4, 125.9, 127.2, 127.5, 128.7, 130.9,
132.5, 134.6, 136.6, 144.9. Anal. found: C 86.65, H 6.64, N
6.59%; calcd for C15H13N: C 86.92, H 6.32, N 6.76%.
4.8.4. 4-Amino-1,2-dimethylphenanthrene-3-carbo-
nitrile (16). Cyclisation of dinitrile 15 (1.0 g, 4 mmol) to
aminonitrile 16 was carried out as described in Section 4.4.
Pale yellow needles (from ethanol); yield 0.74 g (74%); mp
135–1368C; IR (KBr) nmax (cm21) 3437, 3369, 3049, 2998,
2923, 2195, 1639, 1580, 814, 764, 664; dH (CDCl3) 2.53 (s,
3H), 2.63 (s, 3H), 5.18 (s, 2H), 7.58 (t, 1H, J¼7.0 Hz), 7.63
(t, 1H, J¼7.0 Hz), 7.80 (d, 1H, J¼9.1 Hz), 7.87 (d, 1H,
J¼9.2 Hz), 7.91 (d, 1H, J¼7.7 Hz), 9.09 (d, 1H, J¼8.7 Hz);
dC (CDCl3) 14.9, 19.2, 97.1, 117.2, 118.5, 122.8, 124.9,
126.0, 126.2, 126.8, 128.8, 129.9, 130.2, 132.0, 134.7,
135.3, 147.6. Anal. found: C 83.15, H 5.79, N 11.12%; calcd
for C17H14N2: C 82.93, H 5.69, N 11.38%.
4.7.5. 2-Methylphenanthrene (13). 2-Methylphenanthrene
was obtained from amine 12 according to the general
procedure given under Section 4.6. Yield 75 mg (41%); mp
55–578C (lit.15 mp 56–578C); IR (KBr) n max (cm21) 3046,
3026, 1598, 823, 806, 746; dH (CDCl3) 2.55 (s, 3H), 7.44–
7.50 (m, 1H), 7.53–7.67 (m, 4H), 7.70 (m, 1H), 7.86 (m,
1H) 8.56 (d, 1H, J¼8.4 Hz), 8.64 (d, 1H, J¼8.3 Hz); dC
(CDCl3) 19.9, 120.9, 122.8, 122.9, 126.1, 126.4, 126.5,
126.7, 127.8, 128.5, 130.0, 130.7, 130.8, 131.7, 134.9.
4.8.5. 4-Amino-1,2-dimethylphenanthrene (17). Elimin-
ation of the nitrile function from 0.40 g (1.6 mmol) of
aminonitrile 16 was performed as described in Section 4.5.
Pale yellow prisms after sublimation; yield 0.33 g (92%);
mp 88–908C; IR (KBr) nmax (cm21) 3393, 3325, 3061,
2923, 2860, 1618, 814, 751, 626; dH (CDCl3) 2.44 (s, 3H),
2.54 (s, 3H), 4.24 (s, 2H), 6.85 (s, 1H), 7.51 (t, 1H,
J¼7.9 Hz), 7.57 (t, 1H, J¼6.9 Hz), 7.67 (d, 1H, J¼9.2 Hz),
7.86 (d, 1H, J¼7.7 Hz), 7.91 (d, 1H, J¼9.2 Hz), 9.25 (d, 1H,
J¼8.4 Hz); dC (CDCl3) 14.7, 20.8, 117.7, 117.9, 118.4,
123.3, 123.5, 125.1, 125.7, 126.9, 128.3, 131.2, 131.9,
132.8, 134.7, 142.4. Anal. found: C 86.67, H 6.91, N 6.27%;
calcd for C16H15N: C 86.84, H 6.83, N 6.33%.
4.8. Synthesis of 1,2-dimethylphenanthrene (18) from
1-(2-naphthyl)propan-2-one (9)
4.8.1. General procedure for alkylation of 1-(2-
naphthyl)propan-2-one (9) with methyl or ethyl iodide.
Synthesis of 3-(2-naphthyl)butan-2-one (14) and 3-(2-
naphthyl)pentan-2-one (19). In a 50 ml, three-necked flask
equipped with magnetic stirrer, a dropping funnel and a
thermometer were placed 50% sodium hydroxide solution
(15 ml) and TEBA (0.20 g, 0.90 mmol). The mixture was
preheated to 408C and a solution of 1-(2-naphthyl)propan-2-
one (9) (4.7 g, 25 mmol) in toluene (10 ml) was added. The
mixture was stirred vigorously and methyl or ethyl iodide
(33 mmol) was slowly added in the course of 45 min while
the temperature of the reaction mixture was maintained at
40–458C. After the addition of alkyl iodide had been
complete, the stirring was continued for additional 2 h. The
mixture was diluted with water (100 ml) and the product
was extracted with toluene (3£50 ml). The combined
extracts were dried over anhydrous magnesium sulfate.
Toluene was distilled off and oily ketones were distilled
under reduced pressure.
4.8.6. 1,2-Dimethylphenanthrene (18). Elimination of the
amino group from 270 mg (1.22 mmol) of 17 was carried
out as described in Section 4.6. Yield 130 mg (53%); mp
144–1458C; (lit.23 mp 142–1438C); IR (KBr) nmax (cm21
)
3048, 2997, 2922, 1636, 1575, 808, 745, 682; dH (CDCl3)
2.51 (s, 3H), 2.63 (s, 3H), 7.44 (d, 1H, J¼8.4 Hz), 7.55 (t,
1H, J¼8.0 Hz), 7.60 (t, 1H, J¼7.0 Hz), 7.73 (dd, 1H, J¼9.2,
6.1 Hz), 7.85 (d, 1H, J¼7.3 Hz), 8.01 (d, 1H, J¼8.7 Hz),
8.46 (d, 1H, J¼8.5 Hz), 8.65 (d, 1H, J¼8.3 Hz). dC (CDCl3)
15.1, 21.0, 122.7, 122.9, 126.1, 126.4, 126.6, 128.3, 128.7,
129.1, 130.7, 130.9, 131.1, 132.3, 134.4.
4.8.2. 3-(2-Naphthyl)butan-2-one (14). Colourless oil;
yield 2.98 g (59%); bp 95–1008C/20 Pa; (lit.22 no bp is
given); IR (neat) nmax (cm21) 3052, 2979, 1709, 1634, 1601,
1504, 952, 898, 856, 823, 751; dH (CDCl3) 1.47 (d, 3H,
J¼7.0 Hz), 2.05 (s, 3H), 3.88 (q, 1H, J¼6.9 Hz), 7.30 (d,
1H, J¼8.5 Hz), 7.44 (t, 1H, J¼6.8 Hz), 7.47 (t, 1H,
J¼6.7 Hz), 7.67 (s, 1H), 7.77–7.81 (m, 3H); dC (CDCl3)
17.2, 25.5, 53.7, 125.7, 125.8, 126.2, 126.5, 127.6, 128.6,
132.5, 133.6, 138.0, 208.5.
4.9. Synthesis of 4-amino-1-ethyl-2-methylnaphthalene-
3-carbonitrile (21) from 1-naphthylpropan-2-one (9)
4.9.1. 3-(2-Naphthyl)pentan-2-one (19). Ketone 9 (3.68 g,
20 mmol) was alkylated with ethyl iodide as described in
Section 4.8.1. Light brown oil; yield 1.15 g (30%); bp 105–
1068C/10 Pa; IR (neat) nmax (cm21) 3052, 2958, 1714, 1634,
1597, 1504, 818, 747; dH (CDCl3) 0.86 (t, 3H, J¼7.4 Hz),
1.78–1.84 (m, 2H), 2.07 (s, 3H), 3.70 (t, 1H, J¼7.4 Hz),
7.32 (d, 1H, J¼8.3 Hz), 7.45 (t, 1H, J¼6.8 Hz), 7.48 (t, 1H,
4.8.3. 3-(2-Naphthyl)-2-methylbut-1-ene-1,1-dicarbo-
nitrile (15). Condensation of ketone 14 (1.50 g, 7.5 mmol)

W. Krasodomski et al. / Tetrahedron 59 (2003) 5677–5683
5683
2. (a) Sepiol, J. J.; Wilamowski, J. Tetrahedron Lett. 2001, 42,
5287–5289. (b) Sepiol, J. J.; Gora, M.; Luczynski, M. K.
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J¼6.7 Hz), 7.68 (s, 1H), 7.80–7.82 (m, 3H); dC (CDCl3)
12.0, 24.9, 29.1, 61.6, 125.8, 126.0, 126.2, 127.2, 127.6,
127.6, 128.6, 132.6, 133.6, 136.4, 208.5. Anal. found: C
85.02, H 6.97%; calcd for C15H16O: C 84.88, H 7.58%.
3. Benner, B. A.; Wise, S. A.; Currie, L. A.; Klouda, G. A.;
Klinedinst, D. B.; Zweidinger, R. B.; Stevens, R. K.; Lewis,
C. W. Environ. Sci. Technol. 1995, 29, 2382–2389.
4. Hofmann, J.; Zimmermann, G.; Guthier, K.; Hebgen, P.;
Homann, K. H. Liebigs Ann. 1995, 631–636.
4.9.2. 3-(2-Naphthyl)-2-methylpent-1-ene-1,1-dicarbo-
nitrile (20). Condensation of ketone 19 (500 mg,
2.36 mmol) with malonodinitrile was performed according
to the general procedure described in Section 4.3. Pale
5. Oros, D. R.; Simoneit, B. R. T. Fuel 2000, 79, 515–536.
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6. Sjogren, M.; Hang, L.; Rannug, U.; Westerholm, R. Fuel
yellow oil; yield 315 mg (51%); IR (neat) nmax (cm21
)
3052, 2958, 2884, 2226, 1634, 1588, 856, 823, 756; dH
(CDCl3) 1.03 (t, 3H, J¼7.3 Hz), 2.00–2.04 (m, 1H), 2.07 (s,
3H), 2.16–2.20 (m, 1H), 4.37 (t, 1H, J¼7.7 Hz), 7.31 (d,
1H, J¼8.5 Hz), 7.49 (t, 1H, J¼6.8 Hz), 7.52 (t, 1H,
J¼6.8 Hz), 7.80–7.85 (m, 3H), 7.72 (s, 1H); dC (CDCl3)
11.9, 18.2, 24.3, 53.4, 86.0, 111.8, 112.1, 125.4, 126.5,
126.6, 126.6, 127.6, 127.8, 128.9, 132.8, 133.4, 135.2,
182.9. Anal. found: C 83.29, H 6.06, N 10.92%; calcd for
C18H16N2: C 83.08, H 6.15, N 10.77%.
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419–456.
4.9.3. 4-Amino-1-ethyl-2-methylphenanthrene-3-carbo-
nitrile (21). Cyclisation of dinitrile 20 (100 mg,
0.38 mmol) to aminonitrile 21 was performed as described
in Section 4.4. Pale yellow crystals (from methanol); yield
25 mg (25%); mp 1458C; IR (KBr) nmax (cm21) 3437, 3369,
3055, 2961, 2866, 2195, 1611, 1580, 827, 758; dH (CDCl3) d
(ppm) 1.22 (t, 3H, J¼7.6 Hz), 2.62 (s, 3H), 3.00 (q, 2H,
J¼7.6 Hz), 5.16 (s, 2H) 7.56 (t, 1H, J¼6.9 Hz), 7.60 (t, 1H,
J¼7.0 Hz), 7.78 (d, 1H, J¼9.2 Hz), 7.85 (d, 1H, J¼9.2 Hz),
7.88 (d, 1H, J¼7.5 Hz), 9.06 (d, 1H, J¼8.3 Hz); dC (CDCl3)
14.5, 18.3, 21.9, 97.2, 117.5, 118.5, 122.6, 124.9, 126.1,
128.7. 128.8, 129.2, 130.1, 130.4, 132.0, 134.3, 134.6,
147.8. Anal. found: C 82.96, H 6.10, N 10.56%; calcd for
C18H16N2: C 83.08, H 6.15, N 10.77%.
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The support of these investigations by the State Committee
for Scientific Research of Poland (KBN) within Grant No. 3
T09B 030 14 and by Jagiellonian University is gratefully
acknowledged.
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