Synthesis of 1,2-annulated and 1,2-unsubstituted pyrrolo[2,1,5-de] quinolizin-5-ones (cycl[3.3.2]azin-5-ones) via [3+2] cycloadditions of 1-oxoquinolizinium ylides with cyclic alkenes

Article abstract of DOI:10.1039/c0ob00299b

1,2-Annulated pyrrolo[2,1,5-de]quinolizin-5-ones (cycl[3.3.2]azin-5-ones) 6a-6k, 8a-8b and 9 have been synthesized by one pot tandem reactions of 2-acetyl-N-phenacylpyridinium bromides (1a-1d) with electron-deficient cyclic alkenes (N-alkyl(aryl)maleimides, benzoquinones and naphthoquinone) in the presence of sodium carbonate as a base and tetrakispyridinecobalt(ii) dichromate (TPCD) as an oxidant. These products are formed by 1.3-dipolar cycloaddition of the 1-oxoquinolizinium ylides generated in situ from 1a-1d with the alkene followed by dehydrogenation of the primary cycloadduct under the action of TPCD. Similar reactions of the ylides generated in situ from 1a-1f with maleic anhydride gave the 1,2-unsubstituted pyrrolo[2,1,5-de]quinolizin-5-ones 7a-7fvia oxidative bisdecarboxylation and dehydrogenation of the primary cycloadducts under the action of TPCD.

Full text of DOI:10.1039/c0ob00299b

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www.rsc.org/obc | Organic & Biomolecular Chemistry
Synthesis of 1,2-annulated and 1,2-unsubstituted
pyrrolo[2,1,5-de]quinolizin-5-ones (cycl[3.3.2]azin-5-ones) via [3+2]
cycloadditions of 1-oxoquinolizinium ylides with cyclic alkenes†
Yun Liu,a,b Hua-You Hu,c Yan Zhang,a,d Hong-Wen Hua and Jian-Hua Xu*a
Received 22nd June 2010, Accepted 14th July 2010
DOI: 10.1039/c0ob00299b
1,2-Annulated pyrrolo[2,1,5-de]quinolizin-5-ones (cycl[3.3.2]azin-5-ones) 6a–6k, 8a–8b and 9 have been
synthesized by one pot tandem reactions of 2-acetyl-N-phenacylpyridinium bromides (1a–1d) with
electron-deficient cyclic alkenes (N-alkyl(aryl)maleimides, benzoquinones and naphthoquinone) in the
presence of sodium carbonate as a base and tetrakispyridinecobalt(II) dichromate (TPCD) as an
oxidant. These products are formed by 1.3-dipolar cycloaddition of the 1-oxoquinolizinium ylides
generated in situ from 1a–1d with the alkene followed by dehydrogenation of the primary cycloadduct
under the action of TPCD. Similar reactions of the ylides generated in situ from 1a–1f with maleic
anhydride gave the 1,2-unsubstituted pyrrolo[2,1,5-de]quinolizin-5-ones 7a–7f via oxidative
bisdecarboxylation and dehydrogenation of the primary cycloadducts under the action of TPCD.
convenient access of this class of compounds with diversified struc-
Introduction
tures. However, there have not been many reports on the synthesis
of pyrrolo[2,1,5-de]quinolizines up to now, and with these synthe-
ses, only a small number of pyrrolo[2,1.5-de]quinolizines have been
prepared, none of which are with further annulation to the parent
tricyclic core.17–20 We report here a general and regioselective
synthesis of 1,2-annulated pyrrolo[2,1,5-de]quinolizine-5-ones and
1,2-unsubstituted pyrrolo[2,1,5-de]quinolizine-5-ones by tandem
reactions of the 1-hydroxyquinolizinium ylide with cyclic alkenes
in the presence of the mild oxidant tetrakispyridinecobalt(II)
dichromate [Py4Co(HCrO4)2] (TPCD)21 in generally high yield in
an one pot procedure.22
Polycyclic heterocycles with a bridgehead nitrogen atom, especially
those with an indolizine core, constitute an important class of
compounds that have drawn much recent research attention for
both theoretical and practical reasons.1 Their unique electronic
structure and special chemical reactivity have long been of the-
oretical interest.2 Many of these annulated indolizine derivatives
possess a wide variety of biological activity and are now playing
an increasingly important role in designing new antitumor,3 anti-
HIV4 and cardiovascular drugs.5 Moreover, their strong absorp-
tion and fluorescence in the UV-visible region with the wavelength
sensitively depending on the annulation and ring substitution
pattern make them remarkable structural motif in designing novel
classes of dyes, biomarkers6 and electroluminescent materials.7
As a class of annulated indolizines, pyrrolo[2,1.5-de]quinolizines
(cycl[3.3.2]azines) belong to the general family of cyclazines
according to the naming system of Boekelheide8 and Leaver.9
Beside the general interest in their biological activity and opto-
electric properties, their partly hydrogenated structures have been
found in several naturally occurring coccinellid alkaloids10 such as
exochomine11 and chilocorine A,12 B,13 C14 and D.15 They are also
homologues of the myrmicarin alkaloids.16 Therefore, they are in-
teresting synthetic target compounds. Also, the growing attention
given to annulated indolizine derivatives and the resulting demand
for systematic examination of the structure–activity relationship
have raised the task of developing new synthetic approaches for
Results and discussion
The 1- and 3-oxoquinolizinium betaines (I and II in Chart 1) can be
generated by deprotonation of the 1- and 3-hydroxyquinolizinium
salt, which in turn can be prepared by intramolecular aldol
condensation of the 2-acetyl-N-phenacyl pyridinium salt and
2-benzoyl-N-acetonyl pyridinium salt, respectively.23 The 3-oxo
betaine II was used as a dipole to take part in [3+2] cycloadditions
for the synthesis of pyrrolo[2,1,5-de]quinolizin-3-ones.17,20 On the
other hand, the only report so far on the use of the 1-oxo betaine
(I) in [3+2] cycloaddition for the synthesis of the corresponding
pyrrolo[2,1,5-de]quinolizin-5-ones was about the reactions with
electron deficient alkenes in the presence of chromium oxide
as an oxidant to give the products in rather low yield.20 We
have found that, by using cyclic alkenes as dipolarophiles and
TPCD as a dehydrogenative oxidant, the [3+2] cycloadditions
with I afforded the 1,2-annulated pyrrolo[2,1,5-de]quinolizin-5-
ones in satisfactory yield. The pyridinium salts used to prepare the
quinolizinium ylides and the cyclic alkenes used as dipolarophiles
are listed in Chart 1.
aInstitute of Chemistry and Chemical Engineering, Nanjing University, Nan-
jing 210093, PR China. E-mail: xujh@nju.edu.cn; Fax: +86 25 83317761;
Tel: +86 25 83592709
bInstitute of Chemistry and Chemical Engineering, Xuzhou Normal Univer-
sity, Xuzhou 221116, Jiangsu, P. R. China
cInstitute of Chemistry and Chemical Engineering, Huaiyin Normal Univer-
sity, Huaian 223300, PR China
Reaction of the 2-acetyl-N-phenacyl pyridinium salt (1a) with
N-methylmaleimide (2a) under the typical reaction conditions for
using TPCD in [3+2] cycloadditions of pyridinium ylide with
alkene in DMF at 90 ◦C in the presence of sodium carbonate
dKey Laboratory of Analytical Chemistry for Life Science, Ministry of
Education, Nanjing 210093, PR China
† Electronic supplementary information (ESI) available: Copies of 1H and
13C NMR spectra. See DOI: 10.1039/c0ob00299b
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Chart 1
as a base and TPCD as the oxidant21 gave product 6a in 80% yield.
In this reaction, the 1-oxoquinolizinium ylide A generated in situ
from 1a took part in 1,3-dipolar cycloaddition with 2a to give the
primary cycloadduct B, which was dehydrogenated in the reaction
mixture by TPCD to give the product 6a (Scheme 1).
Chart 2
Scheme 1
Similar reactions of the ylides derived from 1a with 2b and 2c
and reactions of the ylides derived from 1b, 1c with 2a, 2b and
2c, respectively, afforded the corresponding products 6b, 6c and
6d–6i, respectively, in 65–88% yield. Reactions of the ylides from
1d with 2a and 2c, respectively, afforded 6j and 6k in 91% and 80%
yield (Chart 2).
Although an alternative mechanism as shown in Scheme 2 via
an intramolecular aldol condensation of the indolizine product 10
could also be envisioned to rationalize the formation of product
6a, we have not found even a trace amount of the indolizine
product 10 in the reaction mixture after the completion of the
reaction. Furthermore, it was found that when the quinolizinium
ylide A was independently prepared and allowed to react with 2c
in DMF at 90 ◦C, the product 6c was obtained in 65% yield. These
facts suggest that the pyrrolo[2,1,5-de]quinolizin-5-ones 6a is most
likely formed by 1,3-dipolar cycloaddition of the ylide A with the
maleimide 2a as shown in Scheme 1.
We recently found that in the [3+2] cycloadditions of pyri-
dinium ylides with maleic anhydride in the presence of the mild
oxidant tetrakispyridinecobalt(II) dichromate (TPCD), TPCD
caused the bisdecarboxylation of the primary cycloadduct to give
1,2-unsubstituted 3-acyl indolizines.24 We have therefore further
investigated the reactions of maleic anhydride with the pyridinium
salts 1a–1f respectively in the presence of sodium carbonate and
TPCD and found that, these reactions gave the 1,2-unsubstituted
3-arylpyrrolo[2,1,5-de]quinolizin-5-ones 7a–7f, respectively, in 62–
Scheme 2
80% yield. These products are proposed to be formed by hydrolysis
of the primary product 11 and the oxidative bisdecarboxylation
of dicarboxylate (12) followed by dehydrogenation under the
action of TPCD (Scheme 3). Therefore, these reactions provide a
novel strategy to regioselectively synthesize the 1,2-unsubstituted
cycl[3.3.2]azines which are otherwise difficult to access because
in the [3+2] cycloaddition of the quionlizinium ylide (I or II)
with electron-deficient alkynes or alkenes, the latter dipolarophiles
have to bear at least one electron-withdrawing group(s). The
smooth formation of the 1,2-unsubstituted 7a–7f also indicated
the generality of the application of TPCD as a promising new
bisdecarboxylation reagent whose mild oxidizing ability can be
well tolerated by such highly p-electron excessive substrates as the
cyclazines and indolizines without strong electron withdrawing
substituents, which are apt to be oxidized by strong oxidants.
Quinones can also serve as the dipolarophiles to take part
in these cycloadditions. Therefore, reactions of the ylide de-
rived from the pyridinium salt 1a with benzoquinone (4a),
2-methoxybenzoquinone (4b) and 1,4-naphthoquinone (5), re-
spectively, gave the corresponding 1,2-annulated pyrrolo[2,1,5-
de]quinolizin-5-ones 8a, 8b and 9 in high yields.
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Table 1 Fluorescence properties of a part of the products
on a Bruker Avance 300 spectrometer at 75 MHz with CDCl3 or
DMSO as solvent. IR spectra were recorded with a Shimadzu IR
440 spectrometer as KBr pellets. Mass spectra were taken on a VG
ZAB-HS spectrometer in the electron impact ionization mode.
Elemental analyses were performed with a Perkin-Elmer 240 C
analyzer.
a
b
Products
lF
UF
6a
6c
7a
9
514
517
489
573
0.351461
0.373289
0.064314
0.030829
a
lF – Fluorescence wavelength. b UF – Fluorescence quantum yield. The
UF values were measured by using perylene as a standard (UF = 0.94) in
degassed cyclohexane.
General procedure for the preparation of 1,2-annulated
pyrrolo[2,1,5-de]quinolizin-5-ones (6, 8 and 9)
A mixture of 2-acetyl-N-phenacyl pyridinium salt 1 (1 mmol), the
cyclic alkene (N-alkyl or arylmaleimides 2a–2c, benzoquinones
4a, 4b and 1,4-naphthoquinone 5, respectively) (2 mmol), TPCD
(1 g) and sodium carbonate (0.371 g) in DMF (15 ml) was heated
at 90 ◦C for 16 h with magnetic stirring. The reaction course
was monitored by TLC. The solvent was removed under reduced
pressure, and the residue was separated by flash chromatography
◦
on a silica gel column with petroleum ether (bp 60–90 C)/ethyl
acetate as an eluent to give the products 6, 8 and 9, respectively.
General procedure for the preparation of 1,2-unsubstituted
pyrrolo[2,1,5-de]quinolizin-5-ones (7)
Scheme 3
A mixture of 2-acetyl-N-phenacyl pyridinium salt 1 (1 mmol),
maleic anhydride 3 (2 mmol, 0.196 g), TPCD (1 g) and sodium
carbonate (3.5 mmol, 0.371 g) in DMF (15 ml) was heated at 90 ◦C
for 16 h with magnetic stirring. The reaction course was monitored
by TLC. The solvent was removed under reduced pressure, and
the residue was separated by flash chromatography on a silica gel
column with petroleum ether (bp 60–90 ◦C)/ethyl acetate as an
eluent to give the products 7.
The UV-visible absorption and fluorescence spectra of a part
of the products have been measured, which show that, some of
these compounds have strong fluorescence in the blue region with
high emission quantum yield (Table 1) and should be interesting
target compounds for biological applications and as opto-electric
materials.
Conclusions
1-Phenyl-8-methyl-3H,7H,9H,10H-pyrrolo[3¢,4¢-3,4]pyrrolo-
[2,1,5-de]◦quinolizine-3,7,9-trione (6a). Yield: 80%; red solid; mp
229–231 C. 1H NMR (300 MHz, CDCl3): d 3.11 (s, 3H), 7.18 (s,
1 H), 7.60 (s, 5H), 8.02 (t, J = 8.1 Hz, 1H), 8.55 (d, J = 8.4 Hz,
1H), 8.63 (dd, J = 7.5, 0.9 Hz, 1H). IR (KBr): 1762, 1731, 1712,
1614, 1434, 1359, 1315,1248, 1137, 809, 768, 736. MS (EI): m/z
(%) 328 (100) [M+], 283 (23), 269 (25), 241 (5), 214 (10), 108 (8).
Anal. Calcd for C20H12N2O3: C, 73.17; H, 3.66; N, 8.54. Found: C,
73.13; H, 3.67; N, 8.54%.
In summary, 1,2-annulated pyrrolo[2,1,5-de]quinolizin-5-one
derivatives (cycl[3.3.2]azin-5-ones) have been prepared by one pot
tandem reactions of 2-acetyl-N-phenacyl pyridinium salts 1a–1d
with cyclic alkenes (maleimides, benzoquinones and naphtho-
quinone) in the presence of sodium carbonate as a base and TPCD
as an oxidant by 1,3-dipolar cycloadditions of the in situ generated
1-oxoquinolizinium ylide with the cyclic alkene and subsequent
oxidative dehydrogenation of the primary cycloadduct. Similar
reactions of the quinolizinium ylides generated in situ from
1a–1f with maleic anhydride, on the other hand, provided a
regioselective synthesis to the otherwise hardly accessible 1,2-
unsubstituted cycl[3.3.2]azin-5-ones by oxidative bisdecarboxy-
lation and dehydrogenation of the primary products under the
action of TPCD. This array of compounds has substantially
expanded the library of the cycl[3.3.2]azine class and may serve
as target compounds for biological and optoelectric properties
investigation.
1-Phenyl-8-ethyl-3H ,7H ,9H ,10H -pyrrolo[3¢,4¢-3,4]pyrrolo-
[2,1,5-de]◦quinolizine-3,7,9-trione (6b). Yield: 82%; red solid; mp
216–218 C. 1H NMR (300 MHz, CDCl3): d 1.21 (t, J = 7.2 Hz,
3H), 3.65 (q, J = 7.2 Hz, 2H), 7.16 (s, 1 H), 7.60 (s, 5H), 8.00 (t,
J = 8.1 Hz, 1H), 8.53 (d, J = 8.4 Hz, 1H), 8.60 (d, J = 7.5 Hz, 1H).
13C NMR (75 MHz, CDCl3): d 175.4, 163.6, 162.4, 145.7, 135.4,
134.3, 130.2, 130.1, 129.2, 129.1, 128.6, 127.8, 127.1, 123.1, 119.8,
118.3, 115.8, 33.3, 14.1. IR (KBr): 1756, 1721, 1706, 1610, 1444,
1344, 1315,1245, 1138, 894, 810, 743. MS (EI): m/z (%) 342 (100)
[M+], 298 (14), 269 (15), 241 (5), 215 (10), 149 (18), 105 (17). Anal.
Calcd for C21H14N2O3: C, 73.68; H, 4.09; N, 8.19. Found: C, 73.62;
H, 4.07; N, 8.17%.
Experimental
General
1,8-Diphenyl-3H,7H,9H,10H-pyrrolo[3¢,4¢-3,4]pyrrolo[2,1,5-
de]quinolizine-3,7,9-trione (6c). Yield: 65%; red solid; mp 246–
248 C. H NMR (300 MHz, CDCl3): d 7.21 (s, 1H), 7.35–7.40
(m, 3H), 7.48 (t, J = 7.3 Hz, 2H), 7.56–7.66 (m, 5H), 8.09 (t, J =
7.5 Hz, 1H), 8.65 (d, J = 8.5 Hz, 1H), 8.69 (d, J = 7.5 Hz, 1H).
13C NMR (75 MHz, CDCl3): d 175.5, 162.7, 161.6, 145.9, 135.3,
Melting points are uncorrected. 1H NMR spectra were measured
on a Bruker DPX 300 spectrometer at 300 MHz with CDCl3 as
solvent. The chemical shifts (d) are reported in parts per million
relative to the residual deuterated solvent signal, and coupling
constants (J) are given in Hz. 13C NMR spectra were measured
◦
1
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134.4, 132.0, 130.5, 130.2, 129.1, 129.0, 128.8, 128.7, 128.4, 128.1,
127.4, 127.2, 123.4, 120.2, 117.8, 116.2. IR (KBr): 1761, 1720,
1648, 1616, 1598, 1501, 1445, 1343, 1137, 870, 746. MS (EI): m/z
(%) 390 (100) [M+], 345 (68), 306 (15), 269 (20), 214 (29), 133 (24),
105 (34), 77(31), 55 (16), 44 (71). Anal. Calcd for C25H14N2O3: C,
76.92; H, 3.59; N, 7.18. Found: C, 76.88; H, 3.62; N, 7.16%.
130.9, 130.1, 129.1, 127.8, 127.7, 126.7, 122.9, 119.7, 118.3, 116.0,
114.1, 55.4, 33.3, 14.1. IR (KBr): 1753, 1702, 1602, 1494, 1346,
1246, 1178, 896, 808. MS (EI): m/z (%) 372 (100) [M+], 328 (19),
299 (5), 241 (5), 230 (1). Anal. Calcd for C22H16N2O4: C, 70.97; H,
4.30; N, 7.53. Found: C, 70.91; H, 4.28; N, 7.55%.
1-(4-Methoxyphenyl)-8-phenyl-3H,7H,9H,10H-pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]quinolizine-3,7,9-trione (6i). Yield: 76%; red
solid; mp 245–247 ◦C.1H NMR (300 MHz, CDCl3): d 3.88 (s, 3H),
7.05 (d, J = 8.7 Hz, 2H), 7.15 (s, 1H), 7.35–7.38 (m, 2H), 7.45 (t,
J = 7.5 Hz, 2H), 7.58 (d, J = 8.7 Hz, 2H), 8.03 (t, J = 7.5 Hz, 2H),
8.61 (t, J = 7.5 Hz, 2H). IR (KBr): 1762, 1718, 1620, 1602, 1492,
1354, 1276, 1246, 1186, 846, 808, 743. MS (EI): m/z (%) 420 (100)
[M+], 375 (24), 345 (2), 299 (8), 230 (2), 202 (2), 149 (7). Anal.
Calcd for C26H16N2O4: C, 74.29; H, 3.81; N, 6.67. Found: C, 74.35;
H, 3.83; N, 6.66%.
1-(4-Chlorophenyl)-8-methyl-3H ,7H ,9H ,10H -pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]◦quinolizine-3,7,9-trione (6d). Yield: 88%; red
1
solid; mp 252–253 C. H NMR (300 MHz, CDCl3): d 3.14 (s,
3H), 7.14 (s, 1 H), 7.57 (s, 4H), 8.03 (t, J = 8.1 Hz, 1H), 8.56 (d,
J = 8.4 Hz, 1H), 8.62 (d, J = 7.5 Hz, 1H). IR (KBr): 1756, 1753,
1709, 1619, 1488, 1375, 1363,1249, 1093, 808, 738. MS (EI): m/z
(%) 362 (100) [M+], 317 (10), 303 (17), 268 (3), 214 (5). Anal. Calcd
for C20H11N2O3Cl: C, 66.30; H, 3.04; N, 7.73. Found: C, 66.35; H,
3.06; N, 7.70%.
1-(4-Chlorophenyl)-8-ethyl-3H,7H,9H,10H-pyrrolo[3¢,4¢-3,4]-
pyrrolo[2,1,5-de]quinolizine-3,7,9-trione (6e). Yield: 85%; red
1-(4-Fluorophenyl)-8-methyl-3H ,7H ,9H ,10H -pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]◦quinolizine-3,7,9-trione (6j). Yield: 91%; red
◦
1
1
solid; mp 260–262 C. H NMR (300 MHz, CDCl3): d 1.25 (t,
J = 7.2 Hz, 3H), 3.69 (q, J = 7.2 Hz, 2H), 7.13 (s, 1 H), 7.57 (s, 4H),
8.03 (td, J = 7.6, 0.9 Hz, 1H), 8.56 (dd, J = 8.5, 1.2 Hz, 1H), 8.62
(dd, J = 7.5, 1.1 Hz, 1H). 13C NMR (75 MHz, CDCl3): d 175.3,
163.5, 162.5, 144.4, 136.6, 134.3, 133.8, 130.6, 130.2, 129.1, 128.9,
127.9, 127.1, 123.2, 129.9, 118.4, 115.4, 33.3, 14.1. IR (KBr): 1749,
1698, 1606, 1488, 1340, 1314,1263, 1136, 1085, 894, 745. MS (EI):
m/z (%) 376 (100) [M+], 361 (20), 332 (37), 304 (12), 214 (5). Anal.
Calcd for C21H13N2O3Cl: C, 67.02; H, 3.46; N, 7.45. Found: C,
67.08; H, 3.48; N, 7.43%.
solid; mp 285–287 C. H NMR (300 MHz, CDCl3): d 3.14 (s,
3H), 7.19 (s, 1 H), 7.28 (t, J = 8.4 Hz, 2H), 7.59–7.64 (m, 2H), 8.05
(t, J = 7.8 Hz, 1H), 8.57 (d, J = 8.4 Hz, 1H), 8.65 (dd, J = 8.4,
0.8 Hz, 1H). IR (KBr): 1760, 1728, 1709, 1621, 1600, 1500, 1236,
1160, 809, 738. MS (EI): m/z (%) 346 (100) [M+], 301 (6), 387 (12)
214 (5). Anal. Calcd for C20H11N2O3F: C, 69.36; H, 3.18; N, 8.09.
Found: C, 69.31; H, 3.19; N, 8.10%.
1-(4-Fluorophenyl)-8-phenyl-3H ,7H ,9H ,10H -pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]◦quinolizine-3,7,9-trione (6k). Yield: 80%; red
1
solid; mp 272–274 C. H NMR (300 MHz, CDCl3): d 7.23 (s,
1-(4-Chlorophenyl)-8-phenyl-3H ,7H ,9H ,10H -pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]◦quinolizine-3,7,9-trione (6f). Yield: 82%; red
1 H), 7.24–7.29 (m, 2H), 7.35–7.43 (m, 3H), 7.49 (t, J = 7.5 Hz,
2H), 7.64 (dd, J = 8.9, 5.2 Hz, 2H), 8.10 (t, J = 8.1 Hz, 1H), 8.67
(t, J = 8.6 Hz, 2H). 13C NMR (75 MHz, CDCl3): d 175.3, 165.1,
163.1, 162.6, 161.8, 144.8, 134.4, 131.9, 131.4, 131.3, 131.2, 131.1,
130.5, 129.1, 128.4, 128.2, 128.1, 127.4, 127.1, 123.5, 120.3, 117.9,
116.1, 116.0, 115.8. IR (KBr): 1760, 1720, 1618, 1602, 1499, 1348,
1240, 1163, 811, 744. MS (EI): m/z (%) 408 (100) [M+], 363 (86),
232 (13), 104 (17), 76 (11). Anal. Calcd for C25H13N2O3F: C, 73.53;
H, 3.19; N, 6.86. Found: C, 73.58; H, 3.17; N, 6.86%.
1
solid; mp 258–260 C. H NMR (300 MHz, CDCl3): d 7.17 (s,
1H), 7.36–7.43 (m, 3H), 7.47–7.60 (m, 6H), 8.08 (t, J = 8.1 Hz,
1H), 8.65 (t, J = 7.5 Hz, 2H). 13C NMR (75 MHz, CDCl3): d
175.4, 162.6, 161.8, 144.6, 136.6, 134.4, 133.7, 131.9, 130.6, 130.5,
129.2, 129.0, 128.4, 128.2, 127.4, 127.1, 123.5, 120.3, 117.9, 115.8.
IR (KBr): 1760, 1720, 1618, 1597, 1503, 1489, 1350, 1319, 1138,
1097, 812, 744. MS (EI): m/z (%) 424 (100) [M+], 379 (50), 345
(8), 303 (6), 268 (3), 214 (12). Anal. Calcd for C25H13N2O3Cl: C,
70.75; H, 3.07; N, 6.60. Found: C, 70.71; H, 3.08; N, 6.58%.
3-Phenyl-5H-pyrrolo[2,1,5-de◦]quinolizin-5-one
(7a). Yield:
68%; yellow solid; mp 124–126 C. 1H NMR (300 MHz, CDCl3):
d 7.29 (s, 1H), 7.35 (d, J = 4.8 Hz, 1H), 7.57–7.62 (m, 3H), 7.66
(d, J = 4.8 Hz, 1H), 7.73 (dd, J = 7.8, 2.3 Hz, 2H), 7.87 (t, J =
7.8 Hz, 1H), 8.28 (d, J = 8.1 Hz, 1H), 8.69 (d, J = 7.5 Hz, 1H).13C
NMR (75 MHz, CDCl3): d 174.4, 144.1, 138.7, 137.0, 133.5,
129.5, 129.3, 129.0, 124.1, 122.9, 122.4, 121.9, 121.5, 118.3, 110.5.
IR (KBr): 1590, 1529, 1473, 1396, 1293, 1269, 1087, 809, 771,
696. MS (EI): m/z (%) 245 (100) [M+], 217 (29), 216 (5), 189 (2),
108 (3), 96 (3). Anal. Calcd for C17H11NO: C, 83.27; H, 4.49; N,
5.71. Found: C, 83.22; H, 4.51; N, 5.72%.
1-(4-Methoxyphenyl)-8-methyl-3H,7H,9H,10H-pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]quinolizine-3,7,9-trione (6g). Yield: 81%; red
solid; mp 281–283 ◦C. 1H NMR (300 MHz, CDCl3): d 3.13 (s, 3H),
3.93 (s, 3H), 7.08 (d, J = 8.4 Hz, 2H), 7.13 (s, 1 H), 7.56 (d, J =
8.4 Hz, 2H), 7.98 (t, J = 8.0 Hz, 1H), 8.52 (d, J = 8.4 Hz, 1H), 8.58
(d, J = 7.5 Hz, 1H). 13C NMR (75 MHz, CDCl3): d 175.4, 163.8,
163.0, 161.5, 145.5, 134.4, 130.8, 130.1, 128.9, 127.7, 126.8, 122.9,
119.7, 118.1, 116.1, 114.1, 55.4, 24.4. IR (KBr): 1763, 1727, 1712,
1617, 1601, 1496, 1284, 1185, 809, 738. MS (EI): m/z (%) 358 (100)
[M+], 313 (5), 299 (13), 283 (1). Anal. Calcd for C21H14N2O4: C,
70.39; H, 3.91; N, 7.82. Found: C, 70.43; H, 3.88; N, 7.81%.
3-(4-Chlorophenyl)-5H-pyrrolo[2,1,5-de]quinolizin-5-one (7b).
◦
1
Yield: 80%; yellow solid; mp 181–183 C. H NMR (300 MHz,
CDCl3): d 7.21 (s, 1H), 7.36 (d, J = 4.5 Hz, 1H), 7.55–7.61 (m,
3H), 7.67 (d, J = 8.1 Hz, 2H), 7.86 (t, J = 7.5 Hz, 1H), 8.28 (d,
J = 8.1 Hz, 1H), 8.68 (d, J = 7.2 Hz, 1H). 13C NMR (75 MHz,
DMSO): d 173.9, 142.3, 139.0, 135.7, 134.9, 133.4, 131.5, 129.6,
125.2, 123.8, 122.2, 121.5, 120.6, 117.9, 111.2. IR (KBr): 1584,
1531, 1478, 1394, 1294, 1274, 1089, 806, 737. MS (EI): m/z (%)
279 (100) [M+], 251 (33), 215 (18), 108 (18), 57 (10). Anal. Calcd
1-(4-Methoxyphenyl)-8-ethyl-3H,7H,9H,10H-pyrrolo[3¢,4¢-
3,4]pyrrolo[2,1,5-de]quinolizine-3,7,9-trione (6h). Yield: 83%; red
solid; mp 228–230 ◦C. 1H NMR (300 MHz, CDCl3): d 1.23 (t, J =
7.2 Hz, 3H), 3.68 (q, J = 7.2 Hz, 2H), 3.93 (s, 3H), 7.08 (d, J =
8.4 Hz, 2H), 7.15 (s, 1 H), 7.58 (d, J = 8.4 Hz, 2H), 7.99 (t, J =
7.8 Hz, 1H), 8.52 (d, J = 8.4 Hz, 1H), 8.58 (d, J = 7.5 Hz, 1H). 13
C
NMR (75 MHz, CDCl3): d 175.3, 163.6, 162.6, 161.5, 145.5, 134.3,
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for C17H10NOCl: C, 73.12; H, 3.58; N, 5.02. Found: C, 73.05; H,
3.61; N, 5.00%.
Calcd for C21H11NO3: C, 77.54; H, 3.38; N, 4.31. Found: C, 77.61;
H, 3.42; N, 4.29%.
3-Phenyl-8-methoxy-3H,7H,10H-isoindolo[1,2,3-de]q◦uinoli-
zine-3,7,10-trione (8b). Yield: 92%; red solid; mp 275–277 C. 1H
NMR (300 MHz, CDCl3): d 3.85 (s, 3H), 5.84 (s, 1H), 7.11 (s, 1H),
7.40 (d, J = 9.6 Hz, 2H), 7.52–7.58 (m, 3H), 8.09 (t, J = 8.1 Hz,
1H), 8.63 (d, J = 7.2 Hz, 1H), 9.05 (d, J = 8.4 Hz, 1H). 13C NMR
(75 MHz, CDCl3): d 181.1, 176.6, 175.1, 160.8, 147.4, 137.9, 135.2,
133.4, 129.6, 129.1, 129.0, 128.4, 128.2, 126.2, 125.3, 120.7, 118.9,
116.2, 110.2, 56.6. IR (KBr): 1660, 1640, 1598, 1457, 1246, 1196,
1163, 1026, 820, 763. MS (EI): m/z (%) 355 (100) [M+], 326 (24),
298 (53), 284 (13), 272 (16), 227 (9), 214 (18), 187 (5), 163 (4), 149
(6). Anal. Calcd for C22H13NO4: C, 74.37; H, 3.66; N, 3.94. Found:
C, 74.32; H, 3.69; N, 3.96%.
3-(4-Methoxyphenyl)-5H-pyrrolo[2,1,◦5-de]quinolizin-5-one (7c).
1
Yield: 77%; yellow solid; mp 178–180 C. H NMR (300 MHz,
CDCl3): d 3.93 (s, 3H), 7.12 (d, J = 8.7 Hz, 2H), 7.30 (s, 1H), 7.35
(d, J = 4.8 Hz, 1H), 7.67–7.71 (m, 3H), 7.85 (t, J = 7.9 Hz, 1H), 8.27
(d, J = 8.3 Hz, 1H), 8.68 (d, J = 7.7 Hz, 1H). 13C NMR (75 MHz,
CDCl3): d 174.8, 160.8, 143.9, 138.5, 133.5, 130.6, 129.3, 123.8,
122.4, 122.2, 121.7, 121.3, 118.0, 114.5, 110.1, 55.5. IR (KBr):
1561, 1522, 1471, 1389, 1274, 1262, 1082, 817, 746. MS (EI): m/z
(%) 275 (100) [M+], 247 (1), 232 (12), 204 (6). Anal. Calcd for
C18H13NO2: C, 78.55; H, 4.73; N, 5.09. Found: C, 78.53; H, 4.75;
N, 5.10%.
3-(4-Fluorophenyl)-5H-pyrrolo[2,1,5-de]quinolizin-5-one (7d).
3H,7H,12H-Benzo[5,6]isoindolo[1,2,3-de]quinolizine-3,7,12-
trione (9). Yield: 78%; red solid; mp 292–294 ◦C. 1H NMR
(300 MHz, CDCl3): d 7.18 (s, 1H), 7.46–7.62 (m, 5H), 7.68–7.80
(m, 2H), 8.03 (dd, J = 7.8, 1.2 Hz, 1H), 8.13 (t, J = 8.1 Hz, 1H),
8.28 (dd, J = 7.2, 1.2 Hz, 1H), 8.72 (dd, J = 7.2, 1.2 Hz, 1H),
9.28 (dd, J = 8.4, 1.1 Hz, 1H). IR (KBr): 1729, 1668, 1641, 1599,
1511, 1453, 1396, 1266, 1237, 939, 719, 702. MS (EI): m/z (%) 375
(100) [M+], 289 (5), 207(9), 149(3), 105 (4), 91(6). Anal. Calcd for
C25H13NO3: C, 80.00; H, 3.47; N, 3.73. Found: C, 80.02; H, 3.50;
N, 3.71%.
◦
1
Yield: 66%; yellow solid; mp 186–188 C. H NMR (300 MHz,
CDCl3): d 7.21 (s, 1H), 7.27 (t, J = 8.7 Hz, 2H), 7.35 (d, J =
4.8 Hz, 1H), 7.61 (d, J = 4.8 Hz, 1H), 7.69–7.74 (m, 2H), 7.86 (t,
J = 8.0 Hz, 1H), 8.28 (d, J = 8.2 Hz, 1H), 8.68 (d, J = 7.7 Hz, 1H).
13C NMR (75 MHz, DMSO): d 173.9, 164.4, 162.4, 142.6, 138.9,
133.4, 133.3, 133.2, 131.9, 131.8, 125.1, 123.7, 122.2, 121.5, 120.7,
117.9, 116.7, 116.5, 111.1. IR (KBr): 1590, 1536, 1493, 1480,
1294, 1224, 1084, 805, 737, 728. MS (EI): m/z (%) 263 (100) [M+],
235 (24), 234 (2), 132 (1), 118 (1). Anal. Calcd for C17H10NOF: C,
77.57; H, 3.80; N, 5.32. Found: C, 77.50; H, 3.83; N, 5.34%.
3-(4-Methylphenyl)-5H-pyrrolo[2,1,5-de]quinolizin-5-one (7e).
Acknowledgements
◦
1
Yield: 62%; yellow solid; mp 183–185 C. H NMR (300 MHz,
CDCl3): d 2.49 (s, 3H), 7.27 (s, 1H), 7.33 (d, J = 4.8 Hz, 1H), 7.38
(d, J = 7.8 Hz, 2H), 7.63 (d, J = 8.1 Hz, 2H), 7.66 (d, J = 4.8 Hz,
1H), 7.84 (t, J = 8.0 Hz, 1H), 8.26 (d, J = 8.2 Hz, 1H), 8.68 (d, J =
7.6 Hz, 1H). IR (KBr): 1579, 1526, 1474, 1390, 1288, 1268, 1083,
806, 723. MS (EI): m/z (%) 259 (100) [M+], 231 (11), 230 (7), 129
(1), 84 (1). Anal. Calcd for C18H13NO: C, 83.40; H, 5.02; N, 5.41.
Found: C, 83.33; H, 5.05; N, 5.43%.
This work was supported by the NSFC (20272024, 20742002),
41th China Planned Projects for Postdoctoral Research Funds
(20070411027), Jiangsu Planned Projects for Postdoctoral Re-
search Funds (0701009B), and Natural Science Foundation of
Jiangsu Province (BK 2007132).
Notes and references
1 (a) Heterocyclic Systems with Bridgehead Nitrogen Atom (Part 1),
W. L. Mosby, Ed.; in The Chemistry of Heterocyclic Compounds, Wiley-
interscience: New York, NY, 1961; Vol. 1; (b) F. J. Swinborne, J. H. Hunt
and G. Klinkert, Adv. Heterocycl. Chem., 1978, 23, 103; (c) W. Flisch,
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3-(2-Naphthyl)-5H-pyrrolo[2,1,5-de]quinolizin-5-one
(7f).
◦
1
Yield: 76%; yellow solid; mp 108–110 C. H NMR (300 MHz,
CDCl3): d 7.39 (d, J = 4.8 Hz, 1H), 7.42 (s, 1H), 7.60–7.63 (m,
2H), 7.72 (d, J = 4.8 Hz, 1H), 7.83–7.92 (m, 2H), 7.95–8.01 (m,
2H), 8.05 (d, J = 8.5 Hz, 1H), 8.23 (s, 1H), 8.30 (d, J = 8.1 Hz,
1H), 8.73 (d, J = 7.6 Hz, 1H). 13C NMR (75 MHz, DMSO): d
173.3, 143.6, 139.0, 134.2, 133.6, 133.4, 133.3, 129.4, 129.2, 129.1,
128.1, 127.7, 127.3, 127.1, 125.4, 123.8, 122.3, 122.0, 121.3, 118.1,
111.6. IR (KBr): 1569, 1525, 1474, 1389, 1272, 1080, 810, 757,
738. MS (EI): m/z (%) 295 (100) [M+], 267 (14), 266 (7), 148 (2),
133 (5), 84 (2). Anal. Calcd for C21H13NO: C, 85.42; H, 4.41; N,
4.75. Found: C, 85.46; H, 4.38; N, 4.76%.
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◦
1
trione (8a). Yield: 90%; red solid; mp 210–212 C. H NMR
(300 MHz, CDCl3): d 6.65 (d, J = 10.2 Hz, 1H), 6.83 (d, J =
10.2 Hz, 1H), 7.13 (s, 1H), 7.40 (d, J = 6.9 Hz, 2H), 7.50–7.59
(m, 3H), 8.08 (t, J = 7.8 Hz, 1H), 8.66 (d, J = 7.5 Hz, 1H), 9.05
(d, J = 8.4 Hz, 1H). 13C NMR (75 MHz, CDCl3): d 182.3, 181.6,
175.3, 147.0, 139.2, 138.3, 137.8, 134.9, 133.4, 129.2, 129.1, 129.0,
128.5, 128.2, 125.5, 125.2, 120.9, 118.9, 117.0. IR (KBr): 1663,
1646, 1640, 1588, 1456, 1265, 1110, 1019, 847, 760. MS (EI): m/z
(%) 325 (100) [M+], 308 (1), 297(1), 268 (2), 239 (1), 214 (4). Anal.
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©