3866 J . Org. Chem., Vol. 64, No. 11, 1999
Sarobe et al.
0.08 g, 0.39 mmol, 98%, off-white crystals; Mp 107-108 °C
(109 °C28); 1H NMR (300 MHz, CDCl3): δ 8.85 (1H, s), 8.65
(1H, d, J 8.1), 7.88 (1H, dd, J 0.9, 7.2), 7.83 (1H, d, J 8.4), 7.76
(1H, d, J 9.0), 7.67 (4H, m), 3.21 (1H, s) ppm; 13C NMR (75
MHz, CDCl3): δ 132.2, 132.0, 130.0, 129.7, 129.5, 128.7, 128.6,
128.1, 127.1, 127.0, 126.9, 126.4, 122.7, 120.0, 84.3, 77.6 ppm;
GC/MS: m/z (%) 202 (100%) [M+.].
2-(1-Ch lor oeth en yl)p h en a n th r en e (16). 2-Acetylphenan-
threne (0.87 g, 4.0 mmol),22 PCl5 (1.06 g, 5.1 mmol), and PCl3
(75 mL) were stirred at room temperature for 24 h. Subse-
quently, water (250 mL) was added, and the reaction mixture
was extracted (diethyl ether 3 × 50 mL). The combined organic
fractions were dried (MgSO4), filtered, and concentrated in
vacuo. The residue was purified by column chromatography
(silica, eluent CHCl3). Yield of 16: 0.54 g, 2.3 mmol, 57%, light
red solid; mp 132-133 °C; 1H NMR (300 MHz, CDCl3): δ 8.67
(1H, d, J 7.8), 8.66 (1H, d, J 8.8), 8.17 (1H, d, J 2.0), 7.90 (1H,
dd, J 2.0, 8.8), 7.88 (1H, d, J 8.8) 7.77 (2H, s), 7.65 (2H, m),
5.97 (1H, d, J 1.8), 5.65 (1H, d, J 1.8) ppm; 13C NMR (75 MHz,
CDCl3): δ 139.7, 134.7, 132.3, 131.7, 130.5, 129.8, 128.6, 127.6,
126.9, 126.7, 126.6, 126.5, 124.1, 122.8, 122.7, 113.0 ppm; GC/
MS: m/z (%) 238 (97), 240 (32) [M+., with appropriate isotope
pattern]. Anal. Calcd for C16H11Cl: C, 80.50; H, 4.64. Found:
C, 80.22; H, 4.69.
3-(1-Ch lor oeth en yl)p h en a n th r en e (17). 3-Acetylphenan-
threne (0.57 g, 2.6 mmol),22 PCl5 (0.72 g, 3.5 mmol), and PCl3
(75 mL) were stirred at room temperature for 24 h. Subse-
quently water (250 mL) was added, and the reaction mixture
was extracted (diethyl ether 3 × 50 mL). The combined organic
fractions were dried (MgSO4) and filtered, and the filtrate was
concentrated in vacuo. The residue was purified by column
chromatography (silica, eluent CHCl3). Yield of 17: 0.43 g, 1.8
mmol, 69%, waxy reddish brown solid; 1H NMR (300 MHz,
CDCl3): δ 8.95 (1H, s), 8.70 (1H, dd, J 0.6, 7.8), 7.87 (1H, dd,
J 1.2, 7.5), 7.83 (1H, AB system, J 0.6, 8.1), 7.80 (1H, AB
system, J 1.8, 8.1), 7.74 (1H, AB system, J 9.0), 7.69 (1H, AB
system, J 9.0), 7.62 (2H, m), 5.95 (1H, d, J 1.8) and 5.66 (1H,
d, J 1.8) ppm; 13C NMR (75 MHz, CDCl3): δ 140.4, 134.8,
132.3, 132.2, 130.0, 128.7, 128.6, 128.0, 126.9, 126.8, 126.3,
124.3, 122.7, 121.2, 113.2 (one quaternary carbon atom not
resolved) ppm; GC/MS: m/z (%) 238 (87), 240 (28) [M+., with
appropriate isotope pattern]. Anal. Calcd for C16H11Cl: C,
80.50; H, 4.64. Found: C, 80.24; H, 4.66
fluoranthene (3) during (incomplete) combustion, i.e.,
phenanthrene (2) appears to be a point of divergence in
PAH growth. Whereas ethynylation of 2 at the 1- or
9-position will give 9 and, subsequently, 3 by a ring
contraction/ring expansion rearrangement,12 ethynylation
at the 4-position will only give 1. Although ethynylation
at the 2- or 3-position will give among others the C16H10
CP-PAH 1, 3, and 9, the latter two compounds are
preferentially formed from in situ generated 2-ethyn-
ylphenanthrene (18), whereas 3-ethynylphenanthrene
(19) will preferentially give 1.
Exp er im en ta l Section
Gen er a l P r oced u r es. All reactions were carried out under
a nitrogen atmosphere. All solvents were purified and dried
by standard procedures. Melting points are uncorrected.
Column chromatography: Merck kieselgel 60 silica (230-400
ASTM). 1H (300 MHz) and 13C (75 MHz) NMR spectra:
δ
values in ppm (reference tetramethylsilane) and J values in
hertz. Infrared spectra: FT-IR, using a diffuse reflection
accessory. The samples were diluted in optically pure potas-
sium bromide. GC-MS; column: DB-17, length 30 m, 0.32 mm
i.d., and film thickness 0.25 µm; injector temperature, 300 °C;
temperature program, 2 min at 150 °C (10 °C min-1) and then
increased to 280 °C; carrier gas He and MS (EI 70 eV)
quadrupole mass spectrometer. GC-FTIR: GC separations
(column: HP-5MS, length 25 m, 0.25 mm i.d., and film
thickness 0.25 µm; injector temperature 275 °C, temperature
program, 2 min at 80 °C and then increased to 290 °C (10 °C
min-1); carrier gas He) and cryotrapped FT-IR-detection.23
Ca u tion : Many (non)-alternant polycyclic aromatic hydro-
carbons (CP-PAH) are potential mutagens and carcinogens;
they should be handled with care.
Acep h en a n t h r ylen e (9),12 P yr a cylen e (20),18,23 a n d
1-Eth yn yl- (21),18,19,23 3-Eth yn yl- (22),18,19,23 a n d 5-Eth yn -
yla cen a p h th ylen e (23).18,23 The spectroscopic and analytical
data of 9 and 20-23 were in agreement with available
literature data.
P yr en e (1), F lu or a n th en e (3), a n d Acen a p h th ylen e (4).
The spectroscopic and analytical data of 1, 3, and 4 were in
agreement with those of commercially available samples.
4-Eth yn ylp h en a n th r en e (15).21 The synthesis of 15 was
carried out using a literature procedure; all spectroscopic and
analytical data of 15 were in agreement with those previously
reported.21 Overall yield of 15: 0.45 g, 2.23 mmol, off white
crystals; mp 43-45 °C (colorless oil21); 1H NMR (300 MHz,
CDCl3): δ 10.34 (1H, m), 7.93 (1H, dd, J 1.4, 7.3), 7.88 (2H,
m), 7.73 (1H, AB system, J 8.8), 7.69 (1H, AB system, J 8.8),
7.65 (2H, m), 7.50 (1H, t, J 7.7), 3.68 (1H, s) ppm; 13C NMR
(75 MHz, CDCl3): δ 136.1, 133.0, 132.9, 130.5, 130.2, 130.0,
128.4, 127.9, 127.2, 127.0, 126.2, 125.9, 125.4, 118.1, 86.4, 83.4
ppm; GC/MS: m/z (%) (MS) 202 (100) [M+.].
Gen er a l F la sh Va cu u m Th er m olysis P r oced u r e. A
Thermolyne 21100 furnace containing an unpacked quartz
tube (length 40 cm and diameter 2.5 cm) was used for all FVT
experiments. Conversion curves were determined by subliming
0.1 g aliquots of the FVT precursors 15, 16, and 17, respec-
tively (sublimation temperature and rate; 160 °C and 50 mg
h-1), into the quartz tube at a pressure of 10-2 Torr and the
temperatures shown in Tables 1 and 2. Pyrolysate product
1
compositions were determined by H and 13C NMR as well as
capillary GC and GC-MS. In the case of 16 and 17 the product
composition of the 1100 °C pyrolysates was also studied using
GC-FT-IR; identical results were found.
2-Eth yn ylp h en a n th r en e (18).28 Pure 18 was obtained in
nearly quantitative yield upon FVT of 2-(1-chloroethenyl)-
phenanthrene (16, 0.1 g, 0.4 mmol) at 900 °C (mass recovery
96%, Table 2). All spectroscopic and analytical data of 18 were
in agreement with those previously reported.28 Yield of 18:
0.08 g, 0.39 mmol, 98%, off-white crystals; mp 75-77 °C (77-
78 °C28); 1H NMR (300 MHz, CDCl3): δ 8.65 (1H, d, J 6.9),
8.63 (1H, d, J 8.1), 8.05 (1H, d, J 1.8), 7.89 (1H, dd, J 1.8, 7.8),
7.70 (5H, m), 3.19 (1H, s) ppm; 13C NMR (75 MHz, CDCl3): δ
132.6, 132.4, 131.7, 130.3, 129.9, 129.6, 128.7, 127.8, 127.1,
126.9, 126.3, 122.9, 122.8, 120.1, 83.8, 77.8 ppm; GC/MS: m/z
(%) 202 (100%) [M+.].
AM120 Ca lcu la tion s. Semiempirical AM1 geometry opti-
mization (MOPAC 7.0) was executed without imposing sym-
metry constraints until GNORM e 0.5 using the eigenvector-
following routine (keywords EF/TS). All minima and transition
states (TS) were characterized by a Hessian calculation
(keywords Force and Large); either none or only one imaginary
vibration, respectively, was found. ∆Hf and ∆H‡ values are
0
reported in kcal mol-1 (1 cal ) 4.184 J , Scheme 5, see also
Supporting Information).
Ack n ow led gm en t . Financial support from the
Basque Government [Beca de Formacion de Investiga-
dores (M.S.)] is gratefully acknowledged.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra of 15-19 as well as AM1 archive files for all minima
and transition states (TS) presented in Scheme 5. This
material is available free of charge via the Internet at
http://pubs.acs.org.
3-Eth yn ylp h en a n th r en e (19).28 Pure 19 was obtained in
nearly quantitative yield upon FVT of 3-(1-chloroethenyl)-
phenanthrene (17, 0.1 g, 0.4 mmol) at 900 °C (mass recovery
99%, Table 2). All spectroscopic and analytical data of 19 were
in agreement with those previously reported.28 Yield of 19:
(28) Hopkins, N. E.; Forooezsh, M. K.; Alworth, W. L. Biochem.
Pharmacol. 1992, 44, 787.
J O982030E