Synthesis of 3-(2-Oxo-2,3-dihydrobenzo[b]furan-3-ylidenehydrazono)-2,3- dihydrobenzo[b]furan-2-one

Article abstract of DOI:10.1134/S1070428007060103

Reactions of benzophenone and fluoren-9-one hydrazones with (2-hydroxyphenyl)oxoacetic acid gave [carboxy(2-hydroxyphenyl) methylidenehydrazono](2-hydroxyphenyl)acetic acid which underwent intramolecular cyclization with formation of 3-(2-oxo-2,3-dihydrob

Full text of DOI:10.1134/S1070428007060103

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 6, pp. 861–863. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © N.A. Pulina, V.V. Zalesov, S.S. Kataev, 2007, published in Zhurnal Organicheskoi Khimii, 2007, Vol. 43, No. 6, pp. 863–865.
Synthesis of 3-(2-Oxo-2,3-dihydrobenzo[b]furan-3-ylidene-
hydrazono)-2,3-dihydrobenzo[b]furan-2-one
N. A. Pulinaa, V. V. Zalesovb, and S. S. Kataevc
a Perm State Pharmaceutical Academy, Federal Agency of Health Protection and Social Development,
ul. Lenina 48, Perm, 614900 Russia
e-mail: pulina_jane@mail.ru
b Perm State University, Perm, Russia
c Perm Regional Forensic Medical Examination Bureau, Perm, Russia
Received April 4, 2006
Abstract—Reactions of benzophenone and fluoren-9-one hydrazones with (2-hydroxyphenyl)oxoacetic acid
gave [carboxy(2-hydroxyphenyl)methylidenehydrazono](2-hydroxyphenyl)acetic acid which underwent intra-
molecular cyclization with formation of 3-(2-oxo-2,3-dihydrobenzo[b]furan-3-ylidenehydrazono)-2,3-dihydro-
benzo[b]furan-2-one. The symmetric azine was also obtained by reactions of (2-hydroxyphenyl)oxoacetic acid
with triphenylphosphoranylidenehydrazones derived from benzophenones, fluoren-9-one, and 1-methyl-2,3-
dihydro-1H-indole-2,3-dione.
DOI: 10.1134/S1070428007060103
The synthesis of hydrazono(2-hydroxyphenyl)acet-
ic acids Ia–Ie and their cyclization into 3-hydrazono-
2,3-dihydrobenzo[b]furan-2-ones IIa–IIe on heating in
glacial acetic acid or concentrated hydrochloric acid
(Scheme 1) were described in [1–3]. Since early 1970s
these transformations remained beyond the scope of
researchers’ interest. Taking into account that com-
pounds I and II may be important from the preparative
viewpoint [4], we performed a study in this field.
of the acid carbonyl group and bands in the region
1617–1599 cm–1, belonging to C=N and C=C bonds.
Compound IV displayed in the H NMR spectrum
a multiplet centered at δ 7.20 ppm from aromatic
protons and a broadened signal at δ 11.00 ppm from
the acid OH protons. In the mass spectrum of IV, the
molecular ion peak (m/z 328) had a relative intensity of
1.9%, and fragment ion peaks did not contradict the
assumed structure.
1
We found that reactions of (2-hydroxyphenyl)oxo-
acetic acid (III) with benzophenone and fluoren-9-one
hydrazones (reactant ratio 1:1 or 2:1) in anhydrous
toluene at 20–25°C give no expected compounds I.
Instead, the products are (2-hydroxyphenyl)[carboxy-
(2-hydroxyphenyl)methylidenehydrazono]acetic acid
(IV, yield 67–72%) and azines Va–Vd (Scheme 2).
Compounds Va–Vd were described in [5–7].
Presumably, the reaction includes intermediate
formation of unsymmetrical azine like A, which re-
acts with the second molecule of acid III to produce
azine IV. This reaction path is confirmed by the pres-
ence of the corresponding ketones (benzophenones or
fluoren-9-one) in the reaction mixture. Acid III also
reacted under analogous conditions with triphenyl-
phosphoranylidenehydrazones derived from benzo-
phenones, fluoren-9-one, and 1-methyl-2,3-dihydro-
1H-indole-2,3-dione to give azine IV, but the yield of
The IR spectrum of IV contained a broadened ab-
sorption band at 1744 cm–1 due to stretching vibrations
Scheme 1.
NR2R3
OH
NR2R3
N
N
R1
R1
Concd. HCl (AcOH)
–H2O
O
O
O
OH
Ia–Ie
IIa–IIe
R1 = R2 = H, R3 = Ph (a), NH2C(O) (b), NH2S(O) (c); R1 = Me, R2 = H, R3 = Ph (d), PhC(O) (e).
861

PULINA et al.
862
Scheme 2.
OH
N
N
O
COOH
CRR'
OH
H2NN=CRR' (–H2O) or
Ph3P=N–N=CRR' (–Ph3PO)
OH
N
III
N
–RR'C=O
COOH
O
O
OH
OH
HO
III
A
IV
R
R'
N
+
N
R'
R
Va–Vd
V, R = R′ = Ph (a), R = Ph, R′ = 4-BrC6H4 (b); RR′ = 9H-fluoren-9-ylidene (c), 1-methyl-2-oxo-2,3-dihydro-1H-indol-3-ylidene (d).
O
O
Ac2O
N
IV
N
–2H2O
O
O
VI
the latter was considerably smaller. Apart from tri-
phenylphosphine oxide, the corresponding symmetric
azines Va–Vd were isolated from the reaction mixture.
Here, as in the above reaction, compound IV is likely
to be formed through intermediate A. Thus, the proc-
esses leading to symmetric azines IV and V are con-
current, and the product ratio is determined most prob-
ably by thermodynamic factors.
On heating in acetic anhydride, compound IV
underwent intramolecular cyclization to 3-(2-oxo-2,3-
dihydrobenzo[b]furan-3-ylidenehydrazono)-2,3-dihy-
drobenzo[b]furan-2-one (VI). The IR spectrum of VI
contained an absorption band at 1812 cm–1 due to
the lactone carbonyl groups, and C=N and C=C vibra-
tions appeared in the region 1609–1598 cm–1. The
aromatic protons gave a four-proton multiplet centered
at δ 7.30 ppm and two two-proton multiplets at δ 7.65
and 7.83 ppm. No molecular ion peak was present in
the mass spectrum of VI, but the fragment ion peaks
(see Experimental) were consistent with its structure.
TLC on Silufol UV-254 plates (diethyl ether–benzene–
acetone, 10:9:1).
[Carboxy(2-hydroxyphenyl)methylidenehydra-
zono](2-hydroxyphenyl)acetic acid (IV). a. A sus-
pension of 0.01 mol of benzophenone or fluoren-9-one
hydrazone in 10 ml of anhydrous toluene was added to
a solution of 1.66 g (0.01 mol) of acid III in 10 ml of
the same solvent, and the mixture was stirred at room
temperature until it became homogeneous. The result-
ing solution was cooled to 0°C, and the precipitate was
filtered off and recrystallized from toluene. Yield 67–
72%, yellow crystals, mp 183–185°C (decomp.). Mass
spectrum, m/z (Irel, %): 310 (2.4), 292 (22.6), 264
(12.3), 238 (15.5), 192 (20.1), 164 (5.7), 146 (7.3), 120
(43.6), 102 (100), 93 (28.6), 76 (21.4). Found, %:
C 58.82; H 3.58; N 8.60. C16H12N2O6. Calculated, %:
C 58.54; H 3.66; N 8.54.
b. A suspension of 0.01 mol of benzophenone or
fluoren-9-one triphenylphosphoranylidenehydrazone in
10 ml of anhydrous toluene was added to a solution of
1.66 g (0.01 mol) of acid III in 10 ml of the same
solvent, and the mixture was stirred for 24 h at room
temperature. The mixture was cooled to 0°C, and the
precipitate was filtered off and recrystallized from
toluene. Yield 42–58%.
EXPERIMENTAL
The IR spectra were recorded in mineral oil on
FSM-1201 and Specord M80 instruments. The 1H NMR
spectra were measured on RYa-2310 (60 MHz) and
Bruker DRX-500 (500 MHz) spectrometers from solu-
tions in DMSO-d6 relative to TMS as internal refer-
ence. The mass spectra (electron impact, 70 eV) were
obtained on a Varian MAT-311 instrument with direct
sample admission into the ion source. The progress of
reactions and the purity of products were monitored by
3-(2-Oxo-2,3-dihydrobenzo[b]furan-3-ylidene-
hydrazono)-2,3-dihydrobenzo[b]furan-2-one (VI).
A mixture of 3.28 g (0.01 mol) of compound IV and
20 ml of acetic anhydride was kept at room tempera-
ture until it became homogeneous. It was then cooled
to 0°C, and the precipitate was filtered off and recrys-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 6 2007

SYNTHESIS OF 3-(2-OXO-2,3-DIHYDROBENZO[b]FURAN-3-YLIDENEHYDRAZONO)-...
863
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tallized from acetonitrile. Yield 2.59 g (89%), orange
crystals, mp 265–267°C (decomp.). Mass spectrum,
m/z (Irel, %): 264 (63.8), 236 (100), 208 (20.5), 102
(5.9), 76 (11.3). Found, %: C 65.68; H 2.78; N 9.55.
C16H8N2O4. Calculated, %: C 65.75; H 2.74; N 9.59.
5. Schweizer, E.E., O’Neil, G.J., and Wemple, J.N., J. Org.
Chem., 1964, vol. 29, p. 1744.
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