630
L. W. Castle and T. A. Elmaaty
Vol 43
Perkin Elmer FT- spectrophotometer Model Spectrum RX1. The
1H and 13C NMR spectra were determined on a Varian Mercury
300 MHz FT-NMR 300 and 75 MHz, respectively, in DMSO-d6
as solvent. Chemical shifts expressed in ppm (ꢀ) relative to TMS
(tetramethylsilane) as an internal standard (ꢀ 0.00 ppm). The
NOESY experiment was acquired using the standard Varian
microprogram with 200 increments and with a mixing time of 200
msec. Microanlytical determinations were performed, in house,
using a Perkin Elmer Series II CHNS/O Analyzer 2400. Reagents
were purchased from Aldrich Chemical.
of the thiophene ring and a doublet at ꢀ 8.92 corresponding
to H-5 of the fused benzene ring as well as remaining
aromatic resonances (H-6, H-7, and H-8) of the fused
benzene ring protons and those of the phenyl group attached
to C-2 of the thiophene ring.
The ir spectrum of 5 shows a broad peak with two maxima
at 3402 and 3275 cm-1 corresponding to the OH absorptions
for both forms of the oxime. Also, no absorption
1
corresponding to a carbonyl group was observed. In the H
NMR spectrum of 5, a singlet at ꢀ 7.86 was observed
corresponding to H-3 of the thiophene ring. Also, two singlets
were observed at 12.52 and 12.50 ppm in a 1:3 ratio
respectively, corresponding to the E and Z forms of the
oxime. A NOESY experiment was performed to determine
2-Phenacylindan-1,3-dione (3).
A mixture of (5.4 g, 100 mmoles) of sodium methoxide, (14.6
g, 100 mmoles) indan-1,3-dione and (19.9 g, 100 mmoles) of
phenacyl bromide in 145 ml of ethanol was heated under reflux
for 30 min. and then cooled. The sodium bromide which formed
was removed by filtration, and the filtrate was concenterated in
vacuo. The residual sirup was dissolved in a mixture of
chloroform (50 ml) and 10% sodium hydroxide (50 ml). The
aqueous phase was separated and re-extracted with chloroform
(50 ml). The aqueous phase was cooled in ice bath, made acidic
with hydrochloric acid, and extracted with chloroform (3 x 50
ml). The combined organic extracts were dried with anhydrous
magnesuim Sulphate, filtered and the filtrate was evaporated in
vacuo to dryness. Recrystallization of the crude product from
ethanol gave compound 3 as yellow crystals, m.p. 188-190 °C,
which diastereomer predominates.
A correlation was
observed between the more intense singlet resonating at ꢀ
12.50 with the singlet resonating at ꢀ 7.86 corresponding to
H-3, indicating the major diasteriomer has the (Z)
configuration (the configuration shown in Scheme 1). There
were no correlations observable between the less intense
signal at ꢀ 12.52 with any resonance signals associated with
the fused aromatic ring. The region between ꢀ 7.2 and ꢀ 7.8
1
ppm in the H spectrum consists of many overlapping
yield 80%, IR (KBr): 3650, 3030, 1740, 1680 cm-1; H-NMR
1
resonances, which display an overly complicated spin pattern,
produced by the presence of both Z / E isomers of the oxime.
The ir spectrum of 6 displayed the characteristic NH
stretching absorption at 3455, and the CO stretch at 1694
cm-1. The NMR spectrum was straight-forward with the
observation of characteristic resonances such as the singlet
at ꢀ 8.47 corresponding to H-3, a doublet at ꢀ 8.92
corresponding to H-9 (the bay region proton of the benzene
moiety) as well as all other expected aromatic resonances.
Because 5 is formed as the Z isomer it is expected that
the compound shown for 6 will be formed by the
Beckmann rearrangement via ring expansion anti to the
oxime. The Beckmann rearrangement product, where the
amide functional group is reversed, would result from the
E isomer. For 6, the carbonyl resonance is observed at ꢀ
190.0 ppm indicating that the carbonyl carbon is adjacent
to the thiophene ring. For the other isomer, where the
carbonyl carbon would be adjacent to benzene ring, the
chemical shift is predicted to be closer to ꢀ 165 ppm.
Elemental analysis of all products was found to be in
good agreement with the proposed structures.
(deutereochloroform): ꢀ 3.3 (t, 1H, CH), 3.9 (d, 2H, CH2), 7.4-
7.9 (m, 9H, arom-H).
2-Phenyl-4H-indeno[1,2-b]thiophene-4-one (4).
A solution of 0.07 g of 3 (0.29 mmole) and 0.08 g of
Lawesson’s reagent (0.19 mmole) in toluene (5 ml) was heated
under reflux for 6 hours. After removal of the solvent in vacuo,
the residual solid was crystallized from ethanol/DMF to give 4
as green crystals, yield 75%; mp 252-253 °C; ir (KBr): 1699
1
(CO) cm-1; H nmr (DMSO-d6): ꢀ 7.24 (t, 1H), 7.48 (m, 3H),
7.68 (d, 2H), 8.48 (s, 1H, H3), 8.92 (d, 1H).
Anal. Calcd. for C17H10OS: C, 77.84; H, 3.84. Found: C,
77.34; H, 3.68.
2-Phenyl-4H-indeno[1,2-b]thiophene-4-one oxime (5).
To a solution 0.75 g of 4 (2.9 mmoles) dissolved in 50 ml of
acetic acid was added a solution of 1.08 g (15 mmoles) of
hydroxylamine hydrochloride dissolved in 5 M sodium acetate
and the mixture was heated under reflux for 4 hours. The
reaction mixture was then poured into cold water, the solid
collected by filtration then crystallized from ethanol/DMF to
give compound 5 as dark green crystals, yield 70%; mp 230-232
1
°C; ir (KBr): 3402 (OH) cm-1; H nmr (DMSO-d6): ꢀ 7.22-7.78
In conclusion this work reports a novel and facile
method for synthesizing derivatives of the indeno[1,2-
b]thiophene and thieno[c]quinoline ring systems starting
with readily available starting materials under straight
forward reaction conditions and with easy workup.
(m, 9H, Ar-H), 7.86 (s, 1H, H3), 12.50 (s, 1H, OH, Z
diastereomer), 12.52 (s 0.3H, OH, E diastereomer).
Anal. Calcd. for C17H11NOS: C, 73.62; H, 4.00; N, 5.05.
Found: C, 73.42; H, 3.86; N, 4.93.
2-Phenylthieno[3,2-c]quinoline-4(5H)one (6).
To a mixture of phosphrous pentoxide (1.8 g, 7.0 mmoles)
and phosphoric acid (1 ml) was added 0.038 g (0.14 mmole) of 5
and the mixture was mechanically stirred at 80-100 °C for 3
hours. The mixture was treated with ice-water and the solid
deposited was filtered and then crystallized from ethanol/
EXPERIMENTAL
All melting points were obtained in open capillary tubes and are
uncorrected. The ir spectra were recorded in KBr discs using a
Castle, Lyle W.
