A complete 1H and 13C NMR data assignment for 3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one

Article abstract of DOI:10.1016/j.saa.2010.11.015

Complete assignments of the ¹H and ¹³C NMR chemical shifts for 3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one were done by means of one- and two-dimensional NMR techniques, including ¹H- ¹H COSY, HMQC and

Full text of DOI:10.1016/j.saa.2010.11.015

Spectrochimica Acta Part A 78 (2011) 559–565
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
A complete 1H and 13C NMR data assignment for
3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one
Plamen N. Pencheva,∗, Neyko M. Stoyanovb, Marin N. Marinova
a Department of Chemistry, University of Plovdiv, 4000 Plovdiv, Bulgaria
b University of Rousse, Branch-Razgrad, 7200 Razgrad, Bulgaria
a r t i c l e i n f o
a b s t r a c t
Complete assignments of the 1H and 13C NMR chemical shifts for 3-phenylmethylene-1H,3H-naphtho-
[1,8-c,d]-pyran-1-one were done by means of one- and two-dimensional NMR techniques, including
1H–1H COSY, HMQC and HMBC spectra. Ab initio quantum chemistry calculations and a shift prediction
by an incremental method provided values close to the proposed assignments. All mid-IR spectral bands
are given as reference data. The DRIFT FTIR, ATR FTIR and Raman spectra are given as a Supplementary
data in JCAMP-DX format, version 4.24. In addition, a method of compound’s synthesis, that has the
product yield higher as compared to already known data in the literature, is given.
Article history:
Received 8 July 2010
Received in revised form 21 October 2010
Accepted 15 November 2010
Keywords:
3-Phenylmethylene-1H,3H-naphtho-[1,8-
c,d]-pyran-1-one
1H NMR
13C NMR
2D NMR
FTIR
© 2010 Elsevier B.V. All rights reserved.
Raman
1. Introduction
compound for a further analysis of a number of derivatives which
will be subsequently reported. The paper supplies fully-assigned
It is known that 2-aryl-2,3-dihydrophenalene-1,3-diones are
compounds which easily isomerize to the respective naphthalides
in alkaline environment when exposed to radiation with UV-light,
thermally treated at above 200 ◦C or treated with concentrated
hydrobromic acid. In this way they can be obtained as intermedi-
ate products related to the synthesis of anticoagulant compounds
[1]. It has been established that such compounds have luminescent
features and can be used as luminophore markers [2].
1H and 13C NMR spectra together with unassigned FTIR and Raman
spectra which will serve as a valuable reference data. In addition,
we present a method of synthesis of 3-phenylmethylene-1H,3H-
naphtho-[1,8-c,d]-pyran-1-one that has the product yield higher
as compared to already known data in the literature.
2. Experimental
For the first time such compound – 3-phenylmethylene-1H,3H-
naphtho-[1,8-c,d]-pyran-1-one – is described in works [3–5]. We
should point out that the yields reported are very low and noth-
ing has been said about some characteristic features, only few
scarce spectral data has been disclosed. The same product was
subsequently obtained at different reaction conditions also by the
Wanag’s team [6,7]. Later this compound was obtained in order to
synthesize a number of new products from the fine organic synthe-
sis [8–11].
2.1. Synthesis of
3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one
The synthesis of 3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-
pyran-1-one (IV) is performed in accordance with reaction
Scheme 1. A mixture of 7.93 g (0.04 mol) 1,8-naphthalic anhy-
dride (I), 16.0 g (0.12 mol) phenylacetic acid and 4.8 g (0.06 mol)
anhydrous sodium acetate is heated at 240–250 ◦C for 2 h. It has
been experimentally established that when heating is performed
for more than 3 h the products (II) and (III) are predominantly
obtained, and for less than 1 h—product IV. After completion of
heating, the reaction mixture is cooled down to 50–60 ◦C and 50 ml
of ethanol are added to it. The mixture is then cooled down to room
temperature and filtered. The solid sediment is dissolved in 3%
aqueous ammonia, and the non-dissolved part is separated through
filtering and edulcorated with water until a neutral reaction has
been obtained. The filtrate is acidified with glacial CH3COOH till
The purpose of the current research is to report a spectral
investigation of the structure of 3-phenylmethylene-1H,3H-
naphtho-[1,8-c,d]-pyran-1-one as the latter appears to be a basic
∗
Corresponding author. Tel.: +359 32 261446.
E-mail addresses: plamen@uni-plovdiv.bg (P.N. Penchev),
nstoianov@uni-ruse.bg (N.M. Stoyanov), marinov@uni-plovdiv.bg (M.N. Marinov).
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.11.015

560
P.N. Penchev et al. / Spectrochimica Acta Part A 78 (2011) 559–565
Scheme 1.
pH 6.5 during which products II and III are obtained (with mp
218–219 ◦C, which is comparable with those in Ref. [6] and Ref.
[10]). The solid sediment is extracted with a petroleum ether in a
Soxhlet apparatus until product IV is isolated. The product obtained
is recrystallized from ethanol.
The melting point of IV was determined with a Koffler appara-
tus. The elemental analysis data were obtained with an automatic
analyzer Carlo Erba 1106. The product was analyzed for C and H,
giving results within 0.2% of the calculated values.
The IR spectrum of IV was registered in KBr pellet on a Perkin-
Elmer 1750 FT-IR Spectrometer from 4000 cm−1 to 450 cm−1 at
resolution 4 cm−1 with 9 scans. A curved baseline correction was
performed with the instrument function FLAT to obtain the real
band intensities cited below.
The IR spectral bands of IV, ꢀmax (cm−1)/transmittance (%):
3436/94.7, 3080/88.9, 3056/82.7, 3020/90.5, 1944/95.6, 1895/96.5,
1851/95.5, 1776/95.6, 1730/10.0, 1668/92.2, 1630/73.6, 1597/88.9,
1582/86.5, 1542/95.6, 1514/74.2, 1495/78.4, 1466/89.7, 1449/81.2,
1440/88.1, 1405/85.0, 1372/90.5, 1362/86.5, 1341/69.7, 1306/92.2,
1251/19.3, 1224/72.9, 1184/39.5, 1156/84.2, 1144/56.1, 1123/81.2,
1085/69.1, 1069/49.0, 1032/88.1, 999/95.6, 979/95.6, 930/93.9,
916/82.7, 869/78.4, 861/82.0, 832/71.0, 797/95.6, 767/59.2,
751/46.4, 690/64.8, 660/86.5, 603/95.6, 569/94.7, 533/98.2,
491/71.4.
The Raman spectrum of IV (the stirred crystals placed in alu-
minium disc) was measured on RAM II (Bruker Optics) with a
focused laser beam of 50 mW power of Nd:YAG laser (1064 nm)
from 4000 cm−1 to 51 cm−1 at resolution 2 cm−1 with 25 scans.
Its Diffuse Reflectance FTIR (DRIFT) and Attenuated Total Reflec-
tion FTIR (ATR) spectra were recorded with a VERTEX 70 FT-IR
spectrometer (Bruker Optics). The used DRIFT accessory is Pray-
ing MantisTM (Harrick Scientific) and crystals of IV were stirred
with KBr; the spectrum is from 4000 cm−1 to 400 cm−1 at reso-
lution 2 cm−1 with 49 scans. The ATR accessory is MIRacleTM with
a one-reflection ZnSe element (Pike) and the stirred crystals of IV
were pressed by an anvil to the reflection element; the spectrum
is from 4500 cm−1 to 600 cm−1 at resolution 2 cm−1 with 16 scans.
Yield: 5.7 g (53%).
mp 148–149 ◦C. (in Ref. [11] 147–148 ◦C)
Elemental analysis data, anal. calcd. (found)/%: C 83.81 (83.72); H
4.44 (4.38).
Rfa = 0.63, Rfb = 0.77 (eluent systems: а—EtAc:petroleum
ether = 1:2; b—CHCI3:CH3COCH3 = 9:1).
2.2. Instrumentation and spectral measurements
1H, 13C and 2D NMR spectra of IV were recorded on a Bruker
Avance II + 600 MHz NMR spectrometer operating at 600.130 MHz
(1H) and 150.903 MHz (13C), using TMS as internal standard and
DMSO-d6 as solvent. The temperature was kept at 293.0 K for all
NMR experiments. Chemical shifts (ı) are expressed in ppm and
coupling constants (J) in Hertz. 1D and 2D NMR spectra were
recorded using the standard Bruker pulse. For 1H, 13C NMR and
2D NMR spectral data of IV see Table 1.

P.N. Penchev et al. / Spectrochimica Acta Part A 78 (2011) 559–565
561
Table 1
1H and 13C NMR spectral data and 1H–1H COSY and HMBC correlations for IV [600.13 MHz (1H) and 150.903 MHz (13C)]a.
Atom
ı(13C) (ppm)
DEPTb
ı(1H) (ppm)
Multiplicity (J, Hz)
1H–1H COSYb
HMBCb
1 (C O)
3
4
5
6
7
8
9
9a
10
10a
11
1ꢀ
2ꢀ
3ꢀ
4ꢀ
5ꢀ
6ꢀ
7ꢀ
159.61
146.21
122.23
127.39
128.32
134.43
126.86
129.23
119.06
127.50
123.70
132.00
108.18
134.13
129.62
128.55
127.53
128.55
129.62
C
C
CH
CH
CH
CH
CH
CH
C
C
C
C
CH
C
CH
CH
CH
CH
CH
8.345
7.741
8.097
8.354
7.784
8.330
dd (7.8, 0.9)
t(7.8)
5, 6c, 1ꢀd
4, 6
3, 6, 9ad, 10, 11d
10a, 11
d (7.8)e
4c, 5
9c, 8
7, 9
4, 7c, 10, 11c
9, 9ad, 10, 11d
9d, 9a, 11
dd (8.4, 1.2)
dd (8.4, 7.2)
dd (7.2, 1.2)
7c, 8
1c, 7, 10
7.059
s
4d, 3ꢀ/7ꢀc
1c, 2ꢀc, 3, 10a, 3ꢀ/7ꢀ
7.941
7.466
7.326
7.466
7.941
dd (7.8, 1.2)
t(7.8)
tt(7.8, 1.2)
t(7.8)
4ꢀ, 5ꢀc, 1ꢀc
3ꢀ, 5ꢀ
1ꢀ, 5ꢀ, 7ꢀ
2ꢀ, 6ꢀ
4ꢀ/6ꢀ, 3ꢀ/7ꢀc
7ꢀ, 5ꢀ
3ꢀ/7ꢀ
2ꢀ, 4ꢀ
dd (7.8, 1.2)
6ꢀ, 5ꢀc, 1ꢀc
1ꢀ, 3ꢀ, 5ꢀ
a
In DMSO-d6 solution. All these assignments were in agreement with COSY, HMQCb and HMBC spectra.
b
Abbreviations: DEPT, Distortionless Enhancement by Polarization Transfer spectrum; 1H–1H COSY—proton–proton homonuclear correlation spectrum; HMQC, Heteronu-
clear Multiple Quantum Correlation experiment; HMBC, long range 1H–13C Heteronuclear Multiple Bond Correlation experiment.
c
These correlations are weak.
d
These correlations are extremely weak.
e
1H signal of H-6 is doublet with widened signals instead of doublet of doublets.
group of 1H signals is modeled by curve-fitting with three dou-
blets of doublets with ı1(7) = 8.354 ppm, 3J1 = 8.4 Hz, 4J1 = 1.2 Hz,
ı2(4) = 8.345 ppm, 3J2 = 7.8 Hz, 4J2 = 0.9 Hz and ı3(9) = 8.330 ppm,
3J3 = 7.2 Hz, 4J3 = 1.2 Hz (subscript at ı corresponds to the number-
ing of signals from high to low shift and in the parentheses is given
the atom numbering from Fig. 1). They are finally assigned to pro-
tons at atoms 7, 4 and 9 (see the discussion that follows). There are
strong 1H–1H COSY correlations (see Table 1 and Fig. 4) between
ı1(7) = 8.354 ppm and ı6(8) = 7.784 ppm, and ı3(9) = 8.330 ppm and
ı6(8) = 7.784 ppm, and a weak one between ı1(7) = 8.354 ppm and
ı3(9) = 8.330 ppm. Since ı3(9) = 8.330 ppm shows a weak HMBC
correlation (see Table 1 and Fig. 5) to 159.61 ppm (13C signal of
the carbonyl group), the former signal is assigned to the proton at
atom 9, while ı1(7) = 8.354 is assigned to H-7, and ı6(8) = 7.784 ppm
to H-8.
Those three types of spectra are given as a Supplementary data in
JCAMP-DX format, version 4.24.
3. Computational details
To additionally verify the proposed assignments, quantum
chemistry calculations were performed by using the Gaussian 98,
Revision A.7 [12]. For the geometry optimization the B3LYP density
functional with 6-31G(d) basis set was used and for the 1H and 13
C
NMR spectra prediction the HF/6-31G(d) calculations were carried
out at the optimized geometry.
4. Results and discussion
Compound IV has the molecular formula C19H12O2. Its structure
and the numbering of the atoms (which is only for spectral assign-
ments) are given in Fig. 1; the structure of IV is only illustrative
and the relevant configuration of the exocyclic double bond (Z or
E) is not a subject of the present paper. The 13C NMR spectrum of IV
showed 17 signals (atoms 3ꢀ and 7ꢀ as well as 4ꢀ and 6ꢀ are magneti-
cally equivalent) and DEPT displayed 10 resonances for CH. The high
intensity (nearly double intensity compared to the others) of the
resonances at 129.62 ppm and 128.55 suggests that each of them
corresponds to two carbon atoms; the signal at 129.62 ppm is for
C-3ꢀ/7ꢀ and that at 128.55 is for C-4ꢀ/6ꢀ. The signal with the highest
chemical shift in 13C NMR spectrum, 159.61 ppm, is for the carbonyl
group (atom 1), and that with the lowest one, 108.18 ppm, for olefin
CH carbon (atom 1ꢀ). The signal at 146.21 ppm is assigned to the
other olefin carbon, atom 3. These five assignments are confirmed
by the 2D spectra (see “discussion” that follows).
The 1H NMR spectrum of IV is presented in Fig. 2; there appear
eight groups of multiplet—the multiplet at ı 8.36–8.32 ppm is
with integral of 3.0. The multiplets at 7.941 ppm and 7.466 ppm
with integral of 2.0 are for the protons in phenyl ring (atoms
3ꢀ/7ꢀ and 4ꢀ/6ꢀ). Heteronuclear Multiple Quantum Correlation
experiment (HMQC) was used to assign proton signals to the cor-
responding carbon signals; the ten HMQC correlations are well
separated—see Fig. 3. Three of the ten HMQC correlations corre-
spond to the multiplet at ı 8.36–8.32 ppm in 1H spectrum (with
integral of 3.0) that is why it is composed of three signals. This
Fig. 1. Structure of 3-Phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one 1.
The numbering of the atoms is only for spectral assignments.

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P.N. Penchev et al. / Spectrochimica Acta Part A 78 (2011) 559–565
Fig. 2. 1H NMR spectrum of IV. The integrals of the signals are shown at the bottom of the multiplets.
The assignment of ı5(3ꢀ/7ꢀ) = 7.941 ppm, ı8(4ꢀ/6ꢀ) = 7.466 ppm
On the other side, there are strong 1H–1H COSY corre-
and ı9(5ꢀ) = 7.326 ppm to the phenyl protons H-3ꢀ/7ꢀ, H-4ꢀ/6ꢀ and
H5ꢀ is straightforward and is confirmed by 1H–1H COSY and the
structure and integrals of the corresponding multiplets. As can be
seen from Fig. 4, the proton at 3ꢀ shows a strong correlation with
the neighboring proton at 4ꢀ (respectively that at 7ꢀ with that at 6ꢀ)
and both protons (at 3ꢀ and 7ꢀ) have a weak one with the proton
at 5ꢀ, giving doublet of doublets for ı5(3ꢀ/7ꢀ). The same correlations
and the correlation of the protons at 4ꢀ and 6ꢀ with the proton at
5ꢀ determine the triplet structure of the signal for the protons at
4ꢀ and 6ꢀ. The signal ı9(5ꢀ) is a triplet of triplets by reason of the
correlations mentioned above. Additionally, there exists a weak
correlation between the proton at 1ꢀ and the protons at 3ꢀ and 7ꢀ;
this confirms that the proton at 1ꢀ is a neighbor of those at 3ꢀ and
7ꢀ.
lations between ı2(4) = 8.345 ppm and ı7(5) = 7.741 ppm, and
ı4(6) = 8.097 ppm and ı7(5) = 7.741 ppm, and a weak one between
ı2(4) = 8.345 ppm and ı4(6) = 8.097 ppm. Since ı2(4) = 8.345 ppm
shows strong HMBC correlation to 146.21 ppm (13C signal of olefin
carbon next to the oxygen), the former signal is assigned to the
proton at atom 4, while ı4(6) = 8.097 ppm is assigned to H-6, and
ı7(5) = 7.741 ppm to H-5. This six assignments made for proton sig-
nals (ı# 1, 2, 3, 4, 6 and 7 to atom# 7, 4, 9, 6, 8 and 5 of the
naphthalene moiety) are additionally supported by the coupling
constants and multiplet structure of the discussed signals—see
Multiplicity column of Table 1. The only exception is the doublet at
8.097 (proton at atom 6) which has to be doublet of doublets but
the weak coupling (4J = 0.9 Hz) does not split the doublet and only
widen its signals.
Fig. 3. Detail of the HMQC spectrum of IV. 1D trace (left) is 13C DEPT-135 NMR spectrum and 1D trace (top) is 1H NMR spectrum.

P.N. Penchev et al. / Spectrochimica Acta Part A 78 (2011) 559–565
563
Fig. 4. Detail of the COSY spectrum of IV. Both 1D traces (top and left) are 1H NMR spectrum of the compound. Three signals marked with * are noise.
in the phenyl ring. The signals ı10(H-1ꢀ) = 7.059 ppm and ı2(H-
4) = 8.345 ppm show strong HMBC correlations with 146.21 ppm
which confirmed the assignment of the latter signal to the olefin
carbon next to the oxygen (C-3). There is also a strong HMBC corre-
lation between ı10 = 7.059 ppm (H-1ꢀ) and 13C signal at 123.70 ppm
(C-10a) which additionally confirmed the assignment of the lat-
ter.
As nearly half of 13C signals build groups with a close shift, the
analysis of HMBC correlations appeared to be more complex. First,
for the CH coupling in benzene rings, as described in the literature
[13], only the meta (vicinal) coupling (3JCH) is usually resolved. The
measured HMBC correlations (see Table 1 and Fig. 5) confirmed that
definitely: for naphthalene moiety the strong couplings are H4–C6,
H4–C10, H5–C10a, H5–C11, H6–C4, H6–C10, H7–C9, H7–C10, H8–C9a
,
,
Third, there is
a
strong HMBC correlation between
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
H8–C11, H9–C7, H9–C10 and for the phenyl ring H3 /7 –C5 , H3 –C7
ı5 = 7.941 ppm (H-3ꢀ/7ꢀ) and 13C signal at 108.18 ppm (C-1ꢀ)
and a strong one between ı10 = 7.059 ppm (H-1ꢀ) and 13C signal
at 129.62 ppm (C-3ꢀ/7ꢀ), which is in accordance with the assign-
ment of proton signals with integral of two ı5 = 7.941 ppm and
ı8 = 7.466 ppm to H-3ꢀ/7ꢀ and H-4ꢀ/6ꢀ.
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
H
4 /6 –C2 , H4 –C6 , H5 –C3 /7 , H6 –C4 , H7 –C3 .
Second, there is an HMBC correlation between ı10 = 7.059 ppm
(signal of H-1ꢀ) and 13C signal at 134.13 ppm (not present in DEPT)
that is why the latter was assigned to carbon 2ꢀ; this assign-
ment is also confirmed by the above mentioned HMBC correlations
Fig. 5. Detail of the HMBC spectrum of IV. 1D trace (left) is 13C NMR spectrum and 1D trace (top) is 1H NMR spectrum.

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P.N. Penchev et al. / Spectrochimica Acta Part A 78 (2011) 559–565
Table 2
Calculated 1H and 13C NMR spectral data for IV.
Atom
ı(13C), expa (ppm)
ı(13C), calc by QCa
(ppm)
ı(13C), calc by
ı(1H), expa (ppm)
ı(1H), calc by QCa
(ppm)
ı(1H), calc by
ChemDrawa (ppm)
ChemDrawa (ppm)
1
3
4
5
6
7
8
9
9a
10
10a
11
1ꢀ
2ꢀ
3ꢀ
4ꢀ
5ꢀ
6ꢀ
7ꢀ
159.61
146.21
122.23
127.39
128.32
134.43
126.86
129.23
119.06
127.50
123.70
132.00
108.18
134.13
129.62
128.55
127.53
128.55
129.62
159.33
142.52
122.55
124.82
127.99
135.50
123.21
135.40
117.69
130.17
124.70
130.03
109.61
132.87
130.94b
126.94c
127.72
126.94c
130.94b
163.0
143.2
124.0
124.5
127.4
132.8
123.2
129.5
122.2
127.7
132.3
134.2
98.1
134.9
126.2
128.4
127.7
128.4
126.2
8.345
7.741
8.097
8.354
7.784
8.330
8.424
7.876
8.139
8.442
7.860
9.180
7.82
7.57
7.76
8.09
7.55
8.43
7.059
6.630
6.41
7.941
7.466
7.326
7.466
7.941
8.459d
7.655e
7.557
7.42
7.26
7.11
7.26
7.42
7.655e
8.459d
a
Abbreviations: exp, experimental value; calcd. by QC, value calculated with quantum chemistry (for the used method see the text); calcd. by ChemDraw, value calculated
with the incremental method of ChemDraw Ultra.
b
Average between 131.30 ppm and 130.57 ppm.
Average between 127.86 ppm and 126.01 ppm.
Average between 9.458 ppm and 7.461 ppm.
Average between 7.762 ppm and 7.548 ppm.
c
d
e
A full set of 1H and 13C NMR assigned spectral data for the com-
pound IV is shown in the Table 1 together with 2D data; the strength
of 2D correlations is given also (see footnotes c and d in Table 1).
There are four aromatic carbons in the naphthalene moiety of
the compound IV without protons: 9a, 10, 10a and 11. As described
above, their assignments are entirely based on the present strong
meta (vicinal) HMBC couplings and the strong HMBC correlation
betweenH-1ꢀ and C-10a. Itwas expectedthat someshift predictions
can confirm our assignments.
The predicted chemical shifts by quantum chemistry calcula-
tions are given in Table 2 together with those predicted by the
incremental method implemented in ChemDraw Ultra 7.0.4 [14].
The 13C shift predictions made by quantum chemistry have a stan-
dard error of 2.3 ppm with a maximum deviation of 6.17 ppm (for
carbon 9) and those for 1H shift have a standard error of 0.37 ppm
with a maximum deviation of 0.85 ppm (for proton at carbon 9).
The incremental method’s predictions have a standard error of
3.4 ppm with a maximum deviation of 10.08 ppm (for carbon 1ꢀ)
and those for 1H shift have a standard error of 0.37 ppm with a
maximum deviation of 0.65 ppm (for proton at carbon 1ꢀ). As seen
from Table 2, the quantum chemistry predictions for C-10 and C-11,
130.17 ppm and 130.03 ppm are very close one another and dif-
fer by more than 1.95 ppm from the assigned shift values. On the
other side, the incremental predictions for these two carbons are in
good agreementwiththeproposed assignments;only the predicted
shift for C-10a, 132.3 ppm, differs significantly from the assigned
value of 123.70 ppm. The shift for C-10a, 124.70 ppm, is predicted
by quantum chemistry and as mentioned above, this assignment is
confirmed by a strong HMBC correlation between H-1ꢀ and C-10a.
ical 1H and 13C shifts. These calculations and a shift prediction by
an incremental method provided shift values close to the proposed
assignments.
The mid-IR, DRIFT FTIR, ATR FTIR and Raman spectra of 3-
phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one
were
recorded. All mid-IR spectral bands are given as reference data and
the other vibrational spectra are attached as Supplementary data
in JCAMP-DX format, version 4.24.
In addition, a method of synthesis of a 3-phenylmethylene-
1Н,3Н-naphtho-[1,8-c,d]-pyran-1-one is described; that method
has the product yield higher as compared to already known data in
the literature.
Acknowledgement
An acknowledgement is made of the financial support of
the National Science Fund for the purchase of Bruker Avance
II+ 600 NMR spectrometer in the framework of the Program
“Promotion of the Research Potential through Unique Scientific
Equipment”—Project UNA-17/2005.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.saa.2010.11.015.
References
[1] N. Stoyanov, S. Minchev, Proc. Varna Univ. Econ. 1 (1998) 21–24 (in Bulgarian).
[2] P. Nikolov, I. Timtcheva, S. Minchev, Annuaire de L‘Universite de Sofia “St. Kl.
Ohridski”, Faculte Chim. 91 (2001) 57–61.
[3] O.M. Ali, W.I. Awad, A.M. Islam, J. Org. Chem. 22 (1957) 517–519.
[4] O.M. Ali, W.I. Awad, A.M. Islam, J. Org. Chem. 23 (1958) 1624–1628.
[5] W.I. Awad, O.M. Ali, J. Org. Chem. 25 (1960) 1872–1874.
[6] G. Wanag, E. Gudriniece, I. Meirovics, Dokl. Acad. Nauk SSSR 146 (1) (1962)
93–96 (in Russian).
[7] I. Meirovics, G. Wanag, Latv. PSR Zinatnu Acad. Vest., Kim. Ser. 5 (1964) 565–570
(in Russian).
[8] M.A. El-Maghraby, A.I.M. Koraiem, Ind. J. Chem. 20B (1981) 73–74.
[9] A.M.S. El-Sharief, N.I.S. Hammad, Y.A. Mohamed, Ind. J. Chem. 20B (1981)
456–459.
5. Summary and conclusions
The 1H, 13C and 2D NMR spectra of 3-phenylmethylene-1H,3H-
naphtho-[1,8-c,d]-pyran-1-one including 1H–1H COSY, HMQC and
HMBC spectra have been recorded and analyzed. The complete
assignments of the 1H and 13C NMR chemical shifts have been
proposed. Density functional theory calculations at the B3LYP/6-
31G(d) level have been used for geometry optimization and
HF/6-31G(d) calculations have been applied to compute the chem-
[10] N.R. Ayyangar, S.V. Joshi, A.G. Lugade, Ind. J. Chem. 20B (1981) 1043–1046.

P.N. Penchev et al. / Spectrochimica Acta Part A 78 (2011) 559–565
565
[11] Y. Asscher, I. Agranat, J. Org. Chem. 45 (1980) 3364–3366.
Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challa-
combe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, J.L. Andres, C. Gonzalez,
M. Head-Gordon, E.S. Replogle, J.A. Pople, Gaussian 98, Revision A.7, Gaussian,
Inc., Pittsburgh, PA, 1998.
[12] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,
V.G. Zakrzewski, J.A. Montgomery, R.E. Stratmann, J.C. Burant, S. Dapprich, J.M.
Millam, A.D. Daniels, K.N. Kudin, M.C. Strain, O. Farkas, J. Tomasi, V. Barone,
M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochter-
ski, G.A. Petersson, P.Y. Ayala, Q. Cui, K. Morokuma, D.K. Malick, A.D. Rabuck,
K. Raghavachari, J.B. Foresman, J. Cioslowski, J.V. Ortiz, A.G. Baboul, B.B. Ste-
fanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R.L. Martin, D.J.
[13] E. Breitmaier, Structure Elucidation By NMR in Organic Chemistry: A Practical
Guide, John Wiley & Sons, Chichester, U.K., 2002, 27.
[14] ChemDraw Ultra 7.0.4 (1985-2002), Cambridge Soft Corporation, 100 Cam-
bridge Park Drive, Cambridge, MA, U.S.A.