Full text of DOI:10.1016/S0040-4020(01)01187-5

TETRAHEDRON
Pergamon
Tetrahedron 58 52002) 925±931
Synthesis and photochromic behaviour of novel 2H-chromenes
derived from ¯uorenone
a,p
Paulo J. Coelho, Luis M. Carvalho, Sergio Rodrigues, A. M. F. Oliveira-Campos,
a
a
b
Â
Roger Dubest, Jean Aubard, Andre Samat and Robert Guglielmetti
c
c
d
d
Â
a
 Â
Departamento de Quõmica, Universidade de Tras-os-Montes e Alto Douro, 5000 Vila Real, Portugal
b
Â
Centro de Quõmica, IBQF, Universidade do Minho, 4710 Braga, Portugal
c
Â
ITODYS, ESA CNRS 7086, Universite de Paris VII, 1 rue Guy de la Brosse, 75005 Paris, France
d
 Â
LCMOM, UMR 6114 CNRS, Universite de la Mediterranee, 13288 Marseille cedex 9, France
Â
Received 16 July 2001; revised 19 October 2001; accepted 30 November 2001
AbstractÐThe synthesis of 2H-chromenes based on a ¯uorenone nucleus is described. Whereas 2,2-diphenyl-2H-pyrano¯uorenones 4±7
and dicyanomethylidene-2H-pyrano¯uorenes 8±10 do not exhibit photochromism, 2,2-diphenyl-2H-pyrano¯uorenols exhibit photochromic
behaviour. The spectrokinetic properties of these compounds in solution are reported. q 2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
phenomenon, based not only on the reversible colour
change, but also on the reversible variation of physico-
chemical parameters on account of structural changes.4
Industrial applications in the ®eld of variable optical trans-
mission materials 5photochromic ophthalmic lenses and
glasses) have met with signi®cant commercial success.5
The synthesis of 2H-chromenes is frequently achieved by
incorporation of a chromenic entity in a molecule with the
desired ring structure and/or substituent pattern.6,7 The
nature of substituents is important to improve photochromic
properties.8±10
Since the discovery of the photochromic behaviour of the
2H-chromenes 52H-1-benzopyrans),1 much research has
been devoted to this important class of oxygenated hetero-
cyclic compounds.2 These interesting molecules undergo a
photo-induced change of colour in solution or in polymer
matrices when exposed to UV radiation or direct sunlight
exposure, returning to the initial state when the illumination
ceases, normally via a thermal pathway. The photochromic
behaviour is based on a photoinduced reversible opening of
the pyran cycle that converts the colourless form 5usually
named the `closed form'), with non-interacting p systems,
in a set of isomers with the pyran ring opened 5the `open
form') leading to distinct absorption spectra due to an
extensively conjugated p system 5Scheme 1).3
In this work, we describe the synthesis and characterisation
of novel 2H-chromenes containing a ¯uorenone nucleus.
The compounds, although not photochromic in solution at
room temperature, constitute excellent precursors for new
photochromic molecules through simple modi®cation of the
carbonyl group.
There are many practical and promising applications for this
Scheme 1.
Keywords: ¯uorenones; photochromism; 2H-chromenes; heterocycles; spectrokinetics.
Corresponding author. Tel.: 1351-259-350284; fax: 1351-259-350480; e-mail: pcoelho@utad.pt
p
0040±4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020501)01187-5

926
P. J. Coelho et al. / Tetrahedron 58 <2002) 925±931
Scheme 2.
2. Results and discussion
2.1. Synthesis
Naphthopyrans can be prepared, in reasonable yield, by
cyclisation of naphthols with 1,1-diphenylprop-2-yn-1-ol
in the presence of a catalytic amount of pyridinium
p-toluenesulphonate 5PPTS).7,11 Using this strategy, the
preparation of 2H-chromenes containing a ¯uorenone
nucleus requires the availability of hydroxy¯uorenones.
Hydroxy¯uorenones 3a,c,d were synthesised in several
reaction steps as shown in Scheme 2 52-hydroxy¯uorenone
3b is commercially available). 2-Phenylbenzoic acids
1a,c,d were prepared from commercial compounds using
known procedures.12±15 Cyclisation of acids 1a,c,d to
methoxy¯uorenones 2a,c,d was achieved using different
methods as shown in Table 1. Treatment of compounds
2a,c,d with HBr/HOAcgave hydroxy¯uorenones 3a,c,d
5quantitative).
Scheme 3.
2H-Pyrano¯uorenones 4±6 are very versatile compounds,
since the carbonyl group can be further functionalised to
new classes of chromenes. Thus, heating an ethanolic
solution of 2H-pyrano¯uorenones 4±6 and malononitrile
5piperidine as catalyst) gave dicyanomethylidene-2H-
pyrano¯uorenes 8±10 in modest yields 5Scheme 4). Under
these conditions, no reaction was observed with chromene
7, probably due to the sterichindrance of the 2,2-diphenyl-
pyrano ring. Treatment of 2H-pyrano¯uorenones 4±6 with
methyl magnesium iodide gave, after hydrolysis, 2H-
pyrano¯uorenols 11±13 in excellent yields.
Table 1. Synthesis of methoxy¯uorenones 2a,c,d
2-Phenylbenzoic acid
Cyclisation method
Product Yield 5%)
1a
1c
1d
6-OMe
4-OMe
3-OMe
H2SO4
PPA
SOCl2/AlCl3
2a
2c
2d
85
73
45
2.2. Photochromic properties
The photochromic characteristics were determined using
¯ash irradiation coupled to a rapid UV±Vis spectrometer
5Table 2).16 2,2-Diphenyl-2H-pyrano¯uorenones 4±7 and
dicyanomethylidene-2H-pyrano¯uorenes 8±10 did not
exhibit photochromic activity.
Condensation of 1,1-diphenylprop-2-yn-1-ol with hydroxy-
¯uorenones 3b±d in CHCl3 under PPTS catalysis gave
2H-pyrano¯uorenones 4±6, respectively in fair yields. The
chromenization reaction of hydroxy¯uorenones 3b,c was
completely regioselective giving only the linear isomer.
Under these conditions no reaction was observed with
1-hydroxy¯uorenone 3a due to the intramolecular hydrogen
bond.7 Thus, it was decided to reduce ¯uorenone 1a to
1-hydroxy¯uorene, which was converted to the correspond-
ing 2H-chromene and oxidised to pyrano¯uorenone 7
5Scheme 3).
For compounds 4±7, this observation can be explained by
the absence of signi®cant activation in the wavelength
domain of the light used for the irradiation 5Fig. 1) 5above
295 nm with the ®lter used in the experiments); photo-
chromic compounds 11±13 exhibit absorption maxima
around 340 nm which allows a ef®cient light absorption.

P. J. Coelho et al. / Tetrahedron 58 <2002) 925±931
927
Scheme 4.
Table 2. Spectrokinetic properties: wavelengths of the absorption maxima of the coloured forms 5l1, l2), colourability 5A01, A02 are the absorbances just after
the ¯ash at l1 and l2, respectively) and thermal bleaching rate 5kD) of 2H-chromenes 11±13 and two reference compounds in toluene 52.5£1025 M) at 258C:
Ref1ˆ3,3-diphenyl-3H-naphtho[2,1-b]pyran, Ref2ˆ2,2-diphenyl-2H-naphtho[1,2-b]pyran16
Compound
Annellation
l15nm)
A01
l25nm)
A02
kD 5amplitude) 5s21) 5%)
11
12
13
Ref1
Ref2
6,7
6,7
7,8
5,6
7,8
427
439
432
432
403
0.52
1.4
0.57
0.84
1.08
524
505
573
±
0.55
0.63
0.15
±
0.160 591) and 0.025 59)
0.120 582) and 0.011 518)
0.910 592) and 0.110 58)
0.090
481
1.62
0.002
Figure 1.
Moreover, it appears that 2H-pyrano¯uorenones 4±7
¯uoresce from the excited state, which usually leads to
cleavage of the C±O bond. Compounds 8±10 are already
deeply coloured before the ¯ash and observation of photo-
chromism is not straightforward. As compounds 11±13
exhibit indeed photochromic behaviour, substitution of a
sp3 carbon atom for a carbonyl in the ®ve-membered ring
fused to the benzopyran moiety is clearly a determining
factor.9
Interestingly, the 2H-1-benzopyran moiety in compounds
11 and 12 is fused at the 6,7-positions, whereas compound

928
P. J. Coelho et al. / Tetrahedron 58 <2002) 925±931
13 is fused at positions 7,8. 6,7-Annellation is in 2H-1-
benzopyrans less frequently encountered than 7,8-annella-
tion.2 The open forms exhibit absorption bands around
430 nm and between 500 and 600 nm 5analogous to ®ve-
membered heterocyclic 2H-chromenes),17 which opens
interesting avenues regarding applications in variable
optical transmission materials. Nevertheless, the photo-
colouration ef®ciency, a function of the quantum yield of
photocolouration and the molar absorptivity of the coloured
species, is low.
300 MHz. 13C Spectra were recorded in CDCl3 on a Varian
Unity Plus at 75.4 MHz. Chemical shifts are given in ppm.
NMR assignments were based on irradiation experiments.
IR spectra were recorded on a Perkin±Elmer FTIR 1600
spectrometer 5wavenumbers in cm21). Elemental analyses
were carried out using a LECO 932 CHNS analyser. Mass
spectra were measured on a AutoSpecE spectrometer.
HRMS determinations were carried out on the molecular
ion, using samples that were puri®ed by TLC. Melting
points are uncorrected. Column chromatography was
performed on Silica 60 570±230 mesh).
As observed for a majority of chromenes dual kinetics of
thermal bleaching with variable amplitudes are observed
5probably due to different isomers). The slow fading rate
is normally attributed to the most stable s-trans-isomer.
The values of kD reveal that the stability, in solution and
at room temperature, of the open coloured forms of
compounds 11±13, are well suited for practical
applications.
4.2.1. 1-Methoxy¯uorenone ,2a). A mixture of 6-methoxy-
2-phenylbenzoicaicd 1a 51.73 g, 7.95 mmol) and H2SO4
510 ml) was stirred for 8 h at rt. The red-coloured solution
was poured into 200 ml of water and extracted with ethyl
acetate 53£50 ml). The organicphase was dried over
anhydrous Na2SO4 and the solvent was evaporated under
reduced pressure. Crude 1-methoxy¯uorenone was puri®ed
by column chromatography 5hexane/ethyl acetate, 80:20).
Yield: 85%. Mp 133±1398C 5lit. 141.5±142.58C20). 1H
NMR: 4.00 5s, 3H, OCH3), 6.85 5d, Jˆ8.4 Hz, 1H), 7.15
5d, Jˆ7.5 Hz, 1H), 7.30 5ddd, Jˆ7.2, 7.2, 1.5 Hz, 1H,
H-7), 7.45 5d, Jˆ7.8 Hz, 1H, H-5), 7.50 5m, 2H, H-6 and
H-3), 7.66 5d, Jˆ7.2 Hz, 1H, H-8).
3. Conclusion
Three new classes of 2H-chromenes, based on a ¯uorenone
nucleus, were synthesised. Although 2H-pyrano¯uorenones
4±7 and dicyanomethylidene-2H-pyrano¯uorenes 8±10
were not photochromic under the experimental conditions
used in the measurements, 2H-pyrano¯uorenes 11±13
exhibit very interesting spectrokinetic properties. In par-
ticular, the rate of thermal bleaching and the absorption
maxima of the open forms are interesting for applications
in the ®eld of variable optical transmission materials. The
presence of a sp3 carbon bridge between the 2,2-diphenyl-
2H-chromene moiety and the phenyl nucleus seems
essential for photochromism in solution at room temperature.
4.2.2. 3-Methoxy¯uorenone ,2c). A mixture of 4-methoxy-
2-phenylbenzoicaicd 1c 50.900 g, 4.13 mmol) and poly-
phosphoricacid 520 g) was stirred for 1 day at 60 8C. The
dark-coloured solution was poured into 200 ml water and
extracted with diethyl ether 53£50 ml). The organicphase
was dried over anhydrous Na2SO4 and the solvent was
evaporated under reduced pressure. Crude 3-methoxy-
¯uorenone was puri®ed by column chromatography
5hexane/ethyl acetate, 80:20). Yield: 73%. Mp 101±
1
104.58C 5lit. 998C20). H NMR: 3.93 5s, 3H, OCH3), 6.75
5dd, Jˆ8.1, 2.4 Hz, 1H, H-2), 7.04 5d, Jˆ2.1 Hz, 1H, H-4),
7.31 5m,1H, H-7), 7.49 5m, 2H, H-5 and H-6), 7.63 5d,
Jˆ8.4 Hz, 1H, H-1), 7.64 5d, Jˆ7.5 Hz, 1H, H-8).
4. Experimental
4.1. Spectrokinetic measurements
4.2.3. 4-Methoxy¯uorenone ,2d). A solution of 3-
methoxy-2-phenylbenzoicaicd
1d 50.400 g, 1.75 mmol)
For the determination of l1 and l2, A01 and A02, and kD,
5.1025 mol dm23 toluene solutions were used. The ¯ash
photolysis apparatus was monitored by a Warner and
Swasey rapid spectrometer, allowing to record visible
absorption spectra of the coloured forms in the 400±
700 nm range 5acquisition time 1 ms, repetitivity
1.25 ms).18,19 Flashes 5duration 50 ms) were generated by
two xenon tubes with a quartz envelope. The energy of
the ¯ashes was 60 J for the full polychromatic emission
spectrum. Thermostated 5258C) 100 mm cells were used.
The light from the analysis lamp 550 W, quartz±iodide)
was ®ltered using a Schott GG400 high-pass ®lter. In a
preliminary experiment, the visible absorption spectrum
and l1 and l2 of the open form were determined. In a
second experiment, the initial absorbances A01 and A02
were measured and the decrease of the absorbance with
time was monitored. The rate constants were calculated
using a bi-exponential model.
and SOCl2 52.0 ml) was heated under re¯ux for 2 h. After
removal of the SOCl2 excess by evaporation under reduced
pressure, the residue was diluted with benzene 510 ml) and
AlCl3 50.300 g, 2.25 mmol) was added. The suspension was
stirred at rt for 10 min and then quenched with NH4Cl 5aq),
and extracted with EtOAc. The organic phase was dried
over anhydrous Na2SO4 and the solvent was evaporated
under reduced pressure. Crude 4-methoxy¯uorenone was
puri®ed by column chromatography 5hexane/ethyl acetate,
1
80:20). Yield: 52%. Mp 102.5±105.58C. H NMR: 4.57 5s,
3H, OCH3), 7.06 5dd, Jˆ7.8, 1.8 Hz, 1H, H-3), 7.20±7.32
5m, 3H, H-6, H-1 and H-2), 7.46 5dd, Jˆ7.5, 7.2, 1.2 Hz, 1H,
H-7), 7.64 5d, Jˆ7.2 Hz, 1H, H-5), 7.84 5d, Jˆ7.2 Hz, 1H,
H-8).
4.3. Synthesis of hydroxy¯uorenones ,3). General
procedure
4.2. Apparatus
A mixture of methoxy¯uorenones 2a,c,d 51.0 mmol), acetic
acid 51.4 ml), and HBr 47% 52.5 ml) was heated under
re¯ux for 8 h. After cooling, the reaction mixture was
1H spectra were recorded in CDCl3 on a Varian Unity Plus at

P. J. Coelho et al. / Tetrahedron 58 <2002) 925±931
929
poured into 100 ml of water and extracted with ethyl
acetate. The organic phase was dried over anhydrous
Na2SO4 and the solvent was evaporated under reduced
pressure. The crude hydroxy¯uorenones were puri®ed
by column chromatography 5hexane/ethyl acetate,
75:25±50:50).
512). Exact mass for C28H18O2: 386.130680; found
386.130644.
4.4.3. 2,2-Diphenyl-2H-pyrano[5,6-c]¯uorenone ,6).
Yield: 25%. Mp 199±200.58C. 1H NMR: 6.36 5d,
Jˆ10 Hz, 1H, H-3), 6.69 5d, Jˆ10 Hz, 1H, H-4), 6.95 5d,
Jˆ7.5 Hz, 1H), 7.23 5d, Jˆ7.5 Hz, 1H), 7.23±7.40 5m, 9H),
7.44±7.52 5m, 4H), 7.93 5d, Jˆ7.2 Hz, 1H, H-8). MS: m/z
5%) 386 510, M1), 358 5100), 329 515), 281 520), 252
518). Exact mass for C28H18O2: 386.130680; found
386.129576.
4.3.1. 1-Hydroxy¯uorenone ,3a). Yield: 95%. Mp 108±
1
109.58C 5lit. 1158C20). H NMR: 6.78 5d, Jˆ8.4 Hz, 1H),
7.05 5d, Jˆ7.2 Hz, 1H), 7.31 5ddd, Jˆ7.2, 8.4, 2.1 Hz, 1H,
H-7), 7.38 5dd, Jˆ7.2, 8.4 Hz, 1H, H-3), 7.51 5m, 2H, H-5
and H-6), 7.65 5d, Jˆ7.5 Hz, 1H, H-8), 8.42 5s, 1H, OH).
4.4.4. 2,2-Diphenyl-2H-pyrano[6,5-a]¯uorenone ,7). A
mixture of 1-hydroxy¯uorenone 3a 5654 mg, 3.33 mmol),
KOH 50.984 g, 17.6 mmol), hydrazine 51.0 ml) and ethane-
1,2-diol 55.0 ml) was stirred for 30 min at 1108C, then 2.5 h
at 1608C and 2.5 h at 2008C. The mixture was treated with a
saturated solution of NH4Cl and extracted with diethyl
ether. The organicphase was dried over anhydrous
Na2SO4 and the solvent was removed by evaporation. A
solution of the crude 1-hydroxy¯uorene, 1,1-diphenyl-
prop-2-yn-1-ol 51.041 g, 5.00 mmol) and PPTS 550 mg) in
50 ml of dry chloroform was re¯uxed for 3 days under an
argon atmosphere. The suspension was then treated with 5%
NaOH 5150 ml) and the aqueous phase was extracted with
chloroform 53£30 ml). The organicphase was dried over
anhydrous Na2SO4 and the solvent was evaporated under
reduced pressure. Pyridine 54.0 ml) and CrO3 51.0 g) were
added to the crude pyrano¯uorene and the suspension was
stirred overnight. The mixture was then treated with HCl
510%) and extracted with ethyl acetate. The organic phase
was dried over anhydrous Na2SO4 and the solvent was
removed by evaporation leaving a yellow oil, which was
puri®ed by column chromatography 5hexane/ethyl acetate
98:2). Recrystallization from pentane/CH2Cl2 gave pure 7.
Yield: 12.4%. Mp 204.5±206.88C. 1H NMR: 6.44 5d,
Jˆ10.2 Hz, 1H, H-3), 6.68 5d, Jˆ10.2 Hz, 1H, H-4), 7.04
5d, Jˆ7.2 Hz, 1H, H-5), 7.12 5d, Jˆ7.2 Hz, 1H, H-6), 7.25±
7.40 5m, 9H), 7.48 5m, 2H, H-7 and H-8), 7.56±7.64 5m,
4H), 7.63 5d, Jˆ7.2 Hz, 1H, H-10). 13C NMR: 83.2 5C-2),
113.2, 119.8, 120.1, 122.8, 123.7, 123.8, 126.5, 127.6,
128.3, 129.0, 129.5, 132.6, 133.9, 134.9, 143.4, 144.6,
145.5, 151.6, 191.1 5CvO). MS: m/z 5%) 386 555, M1),
309 5100) 252 510). Exact mass for C28H18O2:
386.130680; found 386.131033.
4.3.2. 3-Hydroxy¯uorenone ,3c). Yield: 95%. Mp 215±
1
2208C5lit. 2258C20). H NMR: 6.69 5dd, Jˆ7.8, 2.1 Hz,
1H, H-2), 7.00 5d, Jˆ2.1 Hz, 1H, H-4), 7.31 5m,1H, H-7),
7.47 5m, 2H, H-5 and H-6), 7.59 5d, Jˆ8.1 Hz, 1H, H-8),
7.64 5d, Jˆ7.5 Hz, 1H, H-1), 8.50 5s, 1H, OH).
4.3.3. 4-Hydroxy¯uorenone ,3d). Yield: 95%. Mp 250±
1
2538C 5lit. 2498C20). H NMR: 7.10 5d, Jˆ7.2 Hz, 1H,
H-8), 7.13 5dd, Jˆ7.8, 1.5 Hz, 1H, H-1), 7.17 5dd, Jˆ7.2,
1.5 Hz, 1H, H-3), 7.24 5dd, Jˆ7.5, 7.5 Hz, 1H, H-2), 7.32
5ddd, Jˆ7.2, 7.2, 0.9 Hz, 1H, H-6), 7.56 5dd, Jˆ7.2, 1.2 Hz,
1H, H-5), 7.60 5m, 1H, H-7), 9.45 5s, 1H, OH).
4.4. Preparation of pyrano¯uorenones ,4±6). General
procedure
To a mixture of hydroxy¯uorenone 3a,c,d 51.00 mmol), 1,1-
diphenylprop-2-yn-1-ol 5312 mg, 1.50 mmol) and PPTS
550 mg) were added 50 ml of dry chloroform. The
suspension was re¯uxed for 3 days under an argon
atmosphere and then treated with 5% NaOH 5150 ml). The
aqueous phase was extracted with chloroform 53£30 ml).
The organicphase was dried over anhydrous Na 2SO4.
Solvent evaporation gave a yellow oil, which was puri®ed
by column chromatography 5hexane/ethyl acetate 96:4).
Recrystallization from pentane/CH2Cl2 gave a crystalline
material.
4.4.1. 2,2-Diphenyl-2H-pyrano[6,5-b]¯uorenone ,4).
Yield: 31%. Mp 146.5±1488C. IR: 3060, 1714, 1604,
1448, 1430, 1380, 1243, 752, 701. 1H NMR: 6.35 5d,
Jˆ9.9 Hz, 1H, H-3), 6.68 5d, Jˆ9.9 Hz, 1H, H-4), 7.15 5s,
1H, H-11), 7.19 5ddd, Jˆ7.5, 7.5, 1.2 Hz, 1H, H-8), 7.24 5s,
1H, H-5), 7.25±7.46 5m, 12H), 7.58 5d, Jˆ7.2 Hz, 1H, H-9).
13C NMR: 83.1 5C-2), 113.4, 118.4, 119.4, 123.2, 124.1,
126.2, 126.9, 127.8, 128.0, 128.2, 131.6, 134.4, 134.7,
135.3, 137.6, 144.1, 144.4, 153.9, 192.2 5CvO). MS: m/z
5%) 386 565, M1), 309 5100) 252 520). C28H18O2: calcd C
87.05, H 4.66; found C 86.66, H 4.76.
4.5. Reaction of pyrano¯uorenones ,4±6) with
malononitrile. General procedure
A
solution of pyrano¯uorenones 4±6 50.259 mmol),
malononitrile 5185 mg, 2.8 mmol) and piperidine 52 drops)
in ethanol 515 ml) was heated for 30 min under re¯ux. The
reaction mixture was then treated with NH4Cl, extracted
with ethyl acetate, and the organic phase was dried over
anhydrous Na2SO4. Solvent evaporation gave orange oil,
which was puri®ed by column chromatography 5hexane/
CHCl3, increasing polarity). Recrystallization from
methanol/CHCl3 gave a crystalline material.
4.4.2. 2,2-Diphenyl-2H-pyrano[5,6-b]¯uorenone ,5).
Yield: 32%. Mp 250±254.58C. IR: 3083, 1706, 1614,
1
1446, 1184, 1108, 765, 698. H NMR: 6.19 5d, Jˆ9.6 Hz,
1H, H-3), 6.64 5d, Jˆ9.6 Hz, 1H, H-4), 7.07 5s, 1H, H-10),
7.25±7.46 5m, 14H), 7.60 5d, Jˆ7.8 Hz, 1H, H-6). 13C
NMR: 84.0 5C-2), 109.3, 120.2, 120.7, 122.8, 123.1,
123.8, 125.9, 126.9, 127.8, 128.25, 128.27, 129.2, 134.2,
135.1, 143.4, 144.2, 146.7, 158.0, 192.4 5CvO). MS: m/z
5%) 386 585, M1), 309 5100), 252 522), 191 510), 165
4.5.1. 10-Dicyanomethylidene-2,2-diphenyl-2H-pyrano-
[6,5-b]¯uorene ,8). Yield: 60%. Mp 290±2918C. IR:
3056, 2219, 1637, 1560, 1450, 1199, 1130, 730, 700. H
1
NMR: 6.39 5d, Jˆ9.9 Hz, 1H, H-3), 6.67 5d, Jˆ9.9 Hz,

930
P. J. Coelho et al. / Tetrahedron 58 <2002) 925±931
1H, H-4), 7.15 5s, 1H, H-5), 7.21 5ddd, Jˆ7.5, 7.5, 1.2 Hz,
1H, H-8), 7.28±7.44 5m, 12H), 7.93 5s, 1H, H-11), 8.28 5d,
Jˆ8.1 Hz, 1H, H-9). MS: m/z 5%) 434 585, M1), 357 5100),
191 510). Exact mass for C31H18ON2: 434.141913; found
434.141948.
7.44±7.55 5m, 7H). 13C NMR: 26.0 5CH3), 79.0, 82.9 5C-2),
108.3, 120.0, 120.7, 121.3, 123.0, 123.7, 126.9, 127.5,
128.1, 128.4, 128.8, 138.3, 140.2, 142.6, 144.7, 144.9,
150.4, 153.5. MS: m/z 5%) 402 587, M1), 387 527), 384
560), 325 5100), 307 595), 191 522), 165 510). Exact mass
for C29H22O2: 402.161980; found 402.161322.
4.5.2. 6-Dicyanomethylidene-2,2-diphenyl-2H-pyrano-
[5,6-b]¯uorene ,9). Yield: 71%. Mp 275±2778C. IR:
3054, 2219, 1562, 1450, 1199, 1130, 730, 698. H NMR:
4.6.3. 7-Hydroxy-7-methyl-2,2-diphenyl-2H-pyrano[5,6-
c]¯uorene ,13). Yield 82%. Mp 63±668C. H NMR: 1.71
1
1
6.23 5d, Jˆ9.9 Hz, 1H), 6.67 5d, Jˆ10 Hz, 1H), 7.09 5s, 1H,
H-11), 7.25±7.50 5m, 13H), 8.05 5s, 1H, H-5), 8.32 5d,
Jˆ8.4 Hz, 1H, H-7). 13C NMR: 84.5 5C-2), 109.6, 113.7,
113.9, 120.6, 120.8, 122.6, 125.7, 125.9, 126.5, 126.9,
127.0, 128.0, 128.4, 128.7, 129.3, 134.2, 135.2, 141.3,
143.9, 144.9, 158.8, 160.8. MS: m/z 5%) 434 585, M1),
357 580), 191 510), 169 512), 141 517), 132 524), 113 525),
99 530), 85 565), 71 583), 57 5100). Exact mass for
C31H18ON2: 434.141913; found 434.141268.
5s, 3H, CH3), 1.98 5s, 1H, OH), 6.20 5d, Jˆ9.9 Hz, 1H, H-3),
6.68 5d, Jˆ9.9 Hz, 1H, H-4), 6.99 5d, Jˆ10 Hz, 1H), 7.08 5d,
Jˆ7.5 Hz, 1H, H-5), 7.22±7.42 5m, 8H), 7.48±7.60 5m, 5H),
8.10 5d, Jˆ7.5 Hz, 1H). 13C NMR: 26.1 5CH3), 79.6, 83.3
5C-2), 115.7, 121.6, 122.8, 123.3, 123.8, 125.4, 126.6,
126.9, 127.3, 127.5, 127.6, 128.22, 128.24, 128.5, 129.1,
137.4, 145.0, 145.1, 148.1, 149.4, 152.0. MS: m/z 5%) 402
583, M1), 387 5100), 384 580), 325 575), 307 588), 191 515),
165 514). Exact mass for C29H22O2: 402.161980; found
402.161978.
4.5.3. 7-Dicyanomethylidene-2,2-diphenyl-2H-pyrano-
[5,6-c]¯uorene ,10). Yield 53%. 1H NMR: 6.41 5d,
Jˆ10 Hz, 1H, H-3), 6.71 5d, Jˆ10 Hz, 1H, H-4), 6.95 5d,
Jˆ7.5 Hz, 1H, H-5), 7.23±7.50 5m, 12H), 7.96 5d,
Jˆ7.5 Hz, 1H, H-6), 8.01 5d, Jˆ6.9 Hz, 1H, H-11), 8.37
5d, Jˆ7.8 Hz, 1H, H-8). 13C NMR: 84.0 5C-2), 113.68,
113.72, 120.8, 122.8, 124.4, 126.6, 126.8, 126.9, 127.6,
128.0, 128.2, 128.5, 132.6, 134.0, 134.9, 135.6, 141.1,
143.9, 148.3, 161.1. MS: m/z 5%) 434 5100, M1), 357
575). Exact mass for C31H18ON2: 434.141913; found
434.141933.
Acknowledgements
To FCT for ®nancial support through project Praxis XXI/P/
QUI/10021/1998. To Elisa Pinto for NMR spectra
monitoring.
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1002, 754, 700. H NMR: 1.70 5s, 3H, CH3) 1.90 5s, 1H,
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