Triphenyl phosphonium perchlorate - An efficient catalyst for the imino Diels-Alder reaction of imines with electron rich dienophiles. Synthesis of pyranoquinoline, furoquinoline and phenanthridine derivatives

Article abstract of DOI:10.1016/S0040-4020(01)00185-5

Triphenyl phosphonium perchlorate (TPP) is found to be an efficient catalyst for the imino Diels-Alder reaction of aldimines with cyclopentadiene and 3,4-dihydro-2H-pyran is reported for the first time. One pot synthesis of furoquinoline, cyclopentaquinol

Full text of DOI:10.1016/S0040-4020(01)00185-5

TETRAHEDRON
Pergamon
Tetrahedron 57 (2001) 3419±3423
Triphenyl phosphonium perchlorateÐan ef®cient catalyst for the
imino Diels±Alder reaction of imines with electron rich
dienophiles. Synthesis of pyranoquinoline, furoquinoline and
phenanthridine derivatives
Rajagopal Nagarajan, Sundararajan Chitra and Paramasivan T. Perumalp
Organic Chemistry Division, Central Leather Research Institute, Adyar, Chennai 600 020, India
Received 26 October 2000;revised 17 January 2001;accepted 8 February 2001
AbstractÐTriphenyl phosphonium perchlorate (TPP) is found to be an ef®cient catalyst for the imino Diels±Alder reaction of aldimines
with cyclopentadiene and 3,4-dihydro-2H-pyran is reported for the ®rst time. One pot synthesis of furoquinoline, cyclopentaquinolines and
phenanthridine catalysed by TPP is also reported in good yields. q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
were obtained in a ratio of 73:27 and an overall yield of
91% (Scheme 1). The results with various substituents are
given in Table 1. The isomeric ratio is based on isolation by
column chromatography. The most diagnostic parameter for
structural assignment is the scalar coupling constant
between protons H-4a and H-5. In the isomer 3a, the
coupling constant J(4a±5)ˆ4.5 Hz is signi®cantly smaller
and typical for a gauche conformation. This orientation is
present in both conformers of the con®guration having cis
orientation of the pyran ring and phenyl group. In the isomer
4a, the J(4a±5)ˆ10.6 Hz is relevant and indicative of the
anti reciprocal orientation of protons H-5 and H-4a. This
orientation is only possible when the pyran ring and phenyl
ring are on opposite sides of the quinoline ring of 4a.
The pyranoquinoline moiety is present in many alkaloids
such as ¯indersine, oricine and veprisine,1 and derivatives
of these alkaloids possess a wide range of biological
activities such as psychotropic,2 antiallergenic,3 anti-
in¯ammatory4 and estronegic5 activities. The furoquinoline
skeleton is present in many alkaloids like skimmianine and
balfouridine.6 Naturally occuring derivatives include
several Amaryllidaceae and Papaveraceae alkaloids, nota-
bly lycorine, haemanthamine and chelidonine, contain the
phenanthridine framework and the chemistry of phenanthri-
dine alkaloids has been reviewed.7
The imino Diels±Alder reaction of imines with electron rich
dienophiles has been catalyzed by BF3´Et2O,8 lanthanide
tri¯ates,9 GdCl3,10 and protic acids such as TFA11 and
p-TsOH.12 However, to the best of our knowledge, there is
no report of the use of triphenyl phosphonium perchlorate as
a catalyst for the reaction of imines within electron rich
alkenes. This prompted us to use TPP as a catalyst for
such cycloadditions.
TPP also catalyses the reaction of cyclopentadiene with
N-benzylidene aniline 1a and resulted in the formation of
cyclopentaquinoline 7a in 68% yield (Scheme 2). Other
examples are reported in Table 2. The stereochemistry of
the product 7a was assigned based on the low coupling
constant J(4a±5)ˆ2.9 Hz.
Generally, imines derived from phenylglyoxal are highly
hygroscopic, unstable at high temperatures, dif®cult to
purify by distillation or column chromatography and lack
ef®ciency.13 Moreover, the three component coupling
reactions proceed smoothly at room temperature and the
products are obtained in good yields. The reaction of phenyl
glyoxal monohydrate, aniline and 2,3-dihydro-2H-furan
was effectively catalysed by TPP in the presence of
anhydrous Na2SO4 under mild conditions (Scheme 3). The
reaction is instantaneous and produces the furoquinolines 11
and 12 in the ratio of 35:65 in an overall yield of 77%. The
products were characterized by their coupling constant
2. Results and discussion
In the presence of 40 mol% TPP, N-benzylidene aniline 1a
was treated with 3,4-dihydropyran 2 in acetonitrile at room
temperature. After 30 min, pyranoquinolines 3a and 4a
Keywords: triphenyl phosphonium perchlorate;imines;Diels±Alder;
pyranoquinolines;furoquinoline;phenanthridine.
Corresponding author. Tel.: 191-44-4913289;fax: 191-44-4911589;
e-mail: ptperumal@hotmail.com
p
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(01)00185-5

3420
R. Nagarajan et al. / Tetrahedron 57 )2001) 3419±3423
Scheme 1.
Table 1. Synthesis of pyranoquinolines employing 40 mol% PPh3´HClO4
Schiff base
Substituents
R1
Ar
Product ratioa 3:4
Time (min)
Overall yield (%)
R2
R3
1a
1b
1c
1d
H
H
H
H
H
Cl
OCH3
H
H
H
H
H
Ph
Ph
73:27
45:55
51:49
66:34
30 (720)b
91 (25)b
93 (75)b
95 (81)b
80
25b
30
Ph
p-Cl±C6H5
20
a
The isomeric ratio is based on isolation by column chromatography.
Time and yield reported in the literature.8,10
b
Scheme 2.
corresponding cyclopentaquinolines in good yields
(Scheme 4). The cis orientation of the protons were
conformed by their coupling constant values J(4a±5)ˆ
3.1 Hz.
Table 2. Synthesis of cyclopentaquinolines
Schiff base Substituents
Ar
Time (min) Yield (%)
R1
R2
R3
A phenanthridine derivative was prepared by the reaction of
4-nitro-1-naphthylamine and formaldehyde (37% aqueous)
with cyclopentadiene catalysed by TPP in the presence of
anhydrous Na2SO4 in 92% yield (Scheme 5).
1a
1b
1d
1e
1f
H
H
H
H
CH3
H
Cl
H
COOH
H
H
H
H
H
Ph
Ph
30
30
68
65
79
83
78
p-Cl±C6H5 40
Ph
35
35
CH3 Ph
In conclusion, we have shown that TPP is an ef®cient
catalyst for imino Diels±Alder reaction because it is mild
and inexpensive, and only 40 mol% is required for the
cycloaddition reactions. With the imino Diels±Alder reac-
tion catalysed by perchloric acid, complete polymerization
of imine was observed whereas the reaction catalysed by
TPP yielded the product up to 95%, which shows TPP is
effectively catalysing the cycloadditions.
values J(4a±5)ˆ3.1 Hz for 11 and 9.2 Hz for the compound
12.
Similarly, the reaction of phenyl glyoxal and para-
substituted anilines with cyclopentadiene catalysed by
TPP in the presence of anhydrous Na2SO4 yielded the

R. Nagarajan et al. / Tetrahedron 57 )2001) 3419±3423
3421
Scheme 3.
Scheme 4.
Scheme 5.
3. Experimental
added (25 mL) and extracted with CHCl3 (3£10 mL),
washed with brine and dried over anhydrous Na2SO4,
®ltered, and the solvent evaporated. The residue was puri-
®ed by column chromatography with petroleum ether/ethyl
acetate to afford the cycloadducts.
Mass spectra were recorded on a Varian VG 70±70H mass
spectrometer. Melting points were measured in capillary
tubes and are uncorrected. Analytical thin layer chromato-
graphy was performed on precoated sheets of silica gel G of
0.25 mm thickness containing PF 254 indicator (Merck,
Darmstadt). Column chromatography was performed with
silica gel (60±120 mesh;SD Fine, Boisar). IR spectra were
recorded as solids in KBr pellets on a Nicolet Impact-400
spectrometer. NMR spectra were obtained on a Bruker spec-
3.1.1. )4aa,5b,10ba)-3,4,4a,5,6,10b-Hexahydro-5-phenyl-
2H-pyrano[3,2-c]quinoline )3a). 0.440 g (66%) of colour-
less solid, mp 123±1248C;IR (KBr) 3378, 3316, 2936,
1
1605, 1485, 1071 cm21; H NMR (300 MHz, CDCl3) d
7.41±7.24 (m, 6H), 7.13±7.06 (m, 1H), 6.83±6.76 (m,
1H), 6.62 (d, 1H, Jˆ7.6 Hz), 5.34 (d, 1H, Jˆ4.5 Hz), 4.68
(brs, 1H), 3.89 (brs, 1H, NH), 3.61 (d, 1H, Jˆ11.2 Hz),
3.44±3.26 (m, 1H), 2.17±1.99 (m, 1H), 1.75±1.31 (m,
4H); 13C NMR (75 MHz, CDCl3) d 145.2, 141.1, 128.3,
128.0, 127.6, 127.5, 126.8, 119.8, 118.3, 114.4, 72.8, 60.6,
59.3, 38.9, 25.4, 18.0;MS m/z 265 (M1);Anal. calcd for
C18H19NO: C, 81.48;H, 7.22;N, 5.28. Found: C, 81.07;H,
7.25;N, 5.30.
1
trometer. H NMR spectra were recorded at 300 MHz in
CDCl3 and the chemical shifts are given in d relative to
the internal standard TMS. 13C NMR spectra were recorded
at 75 MHz in CDCl3 and the chemical shifts are given in d
relative to the solvent (77.0). Acetonitrile was distilled from
Ê
calcium hydride and dried over 4 A molecular sieves.
3.1. General procedure
To a mixture of imines 1a±d (2.5 mmol) or a mixture of
phenyl glyoxal monohydrate (2.5 mmol) and aromatic
3.1.2. )4aa,5a,10ba)-3,4,4a,5,6,10b-Hexahydro-5-phenyl-
2H-pyrano[3,2-c]quinoline )4a). 0.250 g (25%) of colour-
less solid, mp 94±958C;IR (KBr) 3374, 2928, 1610, 1489,
amines
(2.5 mmol),
dienophiles
[cyclopentadiene
1
(5 mmol) or 3,4-dihydropyran (5 mmol) or dihydrofuran
(5 mmol)] in CH3CN (10 mL), PPh3´HClO4 (0.363 g,
40 mol%) was added and stirred at room temperature for
appropriate times. To the reaction mixture water was
1077 cm21; H NMR (300 MHz, CDCl3) d 7.43±7.34 (m,
5H), 7.26 (d, 1H, Jˆ7.0 Hz), 7.13±7.03 (m, 1H), 6.75±6.59
(m, 1H), 6.54 (d, 1H, Jˆ7.8 Hz), 4.74 (d, 1H, Jˆ10.6 Hz),
4.41 (brs, 1H), 4.10±4.02 (m, 2H), 3.78±3.69 (m, 1H),

3422
R. Nagarajan et al. / Tetrahedron 57 )2001) 3419±3423
2.08±2.02 (m, 1H), 1.89±1.31 (m, 4H); 13C NMR (75 MHz,
CDCl3) d 144.1, 141.7, 130.2, 128.7, 128.0, 127.2, 127.1,
120.0, 116.8, 113.5, 73.9, 68.0, 54.1, 38.2, 23.5, 21.4;MS
m/z 265 (M1);Anal. calcd for C 18H19NO: C, 81.48;H, 7.22;
N, 5.28. Found: C, 81.09;H, 7.24;N, 5.25.
1H), 1.98±1.81 (m, 1H), 1.79±1.54 (m, 4H); 13C NMR
(75 MHz, CDCl3) d 144.1, 140.6, 133.0, 130.4, 129.1,
128.8, 128.5, 120.6, 117.4, 113.9, 74.5, 68.6, 53.9, 38.8,
24.0, 21.9;MS m/z 299 (M1), 301 (M12);Anal. calcd for
C18H18ClNO: C, 72.11;H, 6.05;N, 4.67. Found: C, 72.38;
H, 5.98;N, 4.65.
3.1.3. )4aa,5b,10ba)-9-Chloro-3,4,4a,5,6,10b-hexahydro-
5-phenyl-2H-pyrano[3,2-c]quinoline )3b). 0.313 g (42%)
of colourless solid, mp 154±1558C;IR (KBr) 3362, 3326,
2937, 1615, 1487, 1071 cm21; 1H NMR (300 MHz, CDCl3)
d 7.37±7.28 (m, 6H), 7.03 (d, 1H, Jˆ8.2 Hz), 6.53 (d, 1H,
Jˆ8.3 Hz), 5.24 (brs, 1H), 4.64 (brs, 1H) 3.89 (brs, 1H,
NH), 3.61 (d, 1H, Jˆ11.2 Hz), 3.43±3.31 (m, 1H), 2.13±
2.07 (m, 1H), 1.78±1.31 (m, 4H); 13C NMR (75 MHz,
CDCl3) d 145.6, 141.3, 128.1, 128.0, 127.3, 127.1, 126.8,
119.3, 118.0, 114.4, 72.7, 60.5, 59.0, 38.2, 25.4, 18.2;MS
m/z 265 (M1);Anal. calcd for C 18H18ClNO: C, 72.11;H,
6.05;N, 4.67. Found: C, 72.34;H, 6.09;N, 4.73.
3.1.8. )4aa,5a,10ba)-3,4,4a,5,6,10b-Hexahydro-5-)4-chloro-
phenyl)-2H-pyrano[3,2-c]quinoline )4d). 0.203 g (27%)
of colourless solid, mp 139.2±140.18C;IR (KBr) 3345,
1
2931, 1492, 1265 cm21; H NMR (300 MHz, CDCl3) d
7.34±7.06 (m, 6H), 6.73±6.68 (m, 1H), 6.53 (d, 1H,
Jˆ8.0 Hz), 4.70 (d, 1H, Jˆ10.8 Hz), 4.37 (d, 1H,
Jˆ2.5 Hz), 4.11±4.06 (m, 1H), 4.02 (brs, 1H), 3.75±3.67
(m, 1H), 2.05±2.00 (m, 1H), 1.83±1.60 (m, 4H); 13C NMR
(75 MHz, CDCl3) d 144.5, 140.8, 133.5, 130.9, 129.4,
129.1, 128.8, 120.6, 117.7, 114.2, 74.3, 68.6, 54.2, 38.9,
24.0, 22.0;MS m/z 299 (M1), 301 (M12);Anal. calcd for
C18H18ClNO: C, 72.11;H, 6.05;N, 4.67. Found: C, 72.01;
H, 5.98;N, 4.75.
3.1.4. )4aa,5a,10ba)-9-Chloro-3,4,4a,5,6,10b-hexahydro-
5-phenyl-2H-pyrano[3,2-c]quinoline )4b). 0.382 g (51%)
of colourless solid, mp 122±1238C;IR (KBr) 3348, 2934,
3.1.9. 4-Phenyl-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]-
quinoline )7a). 0.420 g (68%) of colourless solid, mp
120±1218C;IR (KBr) 3353, 1478 cm
1
1494, 1265 cm21; H NMR (300 MHz, CDCl3) d 7.37 (m,
21
5H), 7.19 (s, 1H), 7.03 (d, 1H, Jˆ8.3 Hz), 6.45 (d, 1H,
Jˆ8.3 Hz), 4.67 (d, 1H, Jˆ10.5 Hz), 4.33 (s, 1H), 4.08
(m, 2H), 3.73 (m, 1H), 2.05 (m, 1H), 1.83±1.31 (m, 4H);
13C NMR (75 MHz, CDCl3) d 143.2, 141.8, 130.3, 129.1,
128.6, 127.6, 121.8, 121.7, 115.2, 73.8, 68.4, 54.8, 38.6,
23.9, 22.0;MS m/z 299 (M1), 301 (M12);Anal. calcd for
C18H18ClNO: C, 72.11;H, 6.05;N, 4.67. Found: C, 71.78;
H, 6.02;N, 4.65.
;
1H NMR
(300 MHz, CDCl3) d 7.50 (m, 5H), 7.06 (m, 2H), 6.78 (m,
1H), 6.64 (d, 1H, Jˆ7.9 Hz), 5.90 (m, 1H), 5.71 (m, 1H),
4.67 (d, 1H, Jˆ2.9 Hz), 4.15 (d, 1H, Jˆ8.6 Hz), 3.78 (brs,
1H), 3.05 (m, 1H), 2.71 (m, 1H), 1.85 (m, 1H); 13C NMR
(75 MHz, CDCl3) d 145.6, 142.8, 134.0, 130.3, 129.0,
128.4, 127.2, 126.4, 126.3, 126.0, 119.1, 115.9, 58.0, 46.4,
46.0, 31.5;MS m/z 247 (M1);Anal. calcd for C 18H17N: C,
87.41;H, 6.93;N, 5.66. Found: C, 86.88;H, 6.95;N, 5.68.
3.1.5. )4aa,5b,10ba)-3,4,4a,5,6,10b-Hexahydro-9-meth-
oxy-5-phenyl-2H-pyrano[3,2-c]quinoline )3c). 0.357 g
(48%) of colourless solid, mp 146±1478C;IR (KBr) 3295,
2942, 1502, 1262, 1065 cm21; 1H NMR (300 MHz, CDCl3)
d 7.40±7.29 (m, 5H), 7.03 (s, 1H), 6.73 (d, 1H, Jˆ8.2 Hz),
6.57 (d, 1H, Jˆ8.2 Hz), 5.31 (d, 1H, Jˆ5.4 Hz), 4.61 (s,
1H), 3.73 (s, 3H), 3.67 (brs, 1H), 3.61±3.36 (m, 2H), 2.15
(m, 1H), 1.54±1.26 (m, 4H); 13C NMR (75 MHz, CDCl3) d
152.8, 141.3, 139.1, 128.3, 127.4, 126.8, 121.1, 115.7,
115.0, 111.8, 72.9, 60.8, 59.5, 55.8, 39.1, 25.3, 17.9;MS
m/z 295 (M1);Anal. calcd for C 19H21NO2: C, 77.26;H,
7.17;N, 4.74. Found: C, 77.65;H, 7.20;N, 4.77.
3.1.10. 8-Chloro-4-phenyl-3a,4,5,9b-tetrahydro-3H-cyclo-
penta[c]quinoline )7b). 0.457 g (65%) of white solid, mp
150±1518C;IR (KBr) 3363, 1469 cm
21
;
1H NMR
(300 MHz, CDCl3) d 7.44±7.31 (m, 5H), 7.04 (d, 1H,
Jˆ2.1 Hz), 6.96 (dd, 1H, Jˆ2.2, 8.4 Hz), 6.56 (d, 1H,
Jˆ8.5 Hz), 5.81 (d, 1H, Jˆ2.6 Hz), 5.69 (s, 1H), 4.61 (d,
1H, Jˆ3.0 Hz), 4.08 (d, 1H, Jˆ8.6 Hz), 3.76 (brs, 1H),
3.05±2.96 (m, 1H), 2.67±2.58 (m, 1H), 1.87±1.78 (m,
1H); 13C NMR (75 MHz, CDCl3) d 144.1, 142.3, 133.4,
130.8, 128.6, 128.5, 127.6, 127.3, 126.5, 123.4, 116.9,
58.0, 46.2, 45.7, 31.4;MS m/z 281 (M1);283 (M 12);
Anal. calcd for C18H16ClN: C, 76.72;H, 5.72;N, 4.97.
Found: C, 76.40;H, 5.74;N, 4.98.
3.1.6. )4aa,5a,10ba)-3,4,4a,5,6,10b-Hexahydro-9-meth-
oxy-5-phenyl-2H-pyrano[3,2-c]quinoline )4c). 0.343 g
(47%), dense liquid;IR (neat) 3361, 2938, 1504, 1255,
3.1.11. 4-)4-Chlorophenyl)-3a,4,5,9b-tetrahydro-3H-cyclo-
penta[c]quinoline )7d). 0.555 g (79%) of colourless solid,
mp 141±1428C;IR (KBr) 3363, 1478 cm
1
1032 cm21; H NMR (300 MHz, CDCl3) d 7.43±7.27 (m,
21
5H), 6.82 (s, 1H), 6.75 (d, 1H, Jˆ9.1 Hz), 6.49 (d, 1H,
Jˆ8.5 Hz), 4.62 (d, 1H, Jˆ10.5 Hz), 4.38 (s, 1H), 4.10
(m, 1H), 3.75 (m, 5H), 2.10 (m, 1H), 1.84±1.30 (m, 4H);
13C NMR (75 MHz, CDCl3) d 151.9, 142.2, 138.7, 128.1,
127.7, 121.3, 116.7, 115.5, 114.7, 74.5, 68.3, 55.7, 55.1,
38.8, 24.0, 21.9;MS m/z 295 (M1).
;
1H NMR
(300 MHz, CDCl3) d 7.40 (m, 4H), 7.36±6.98 (m, 2H),
6.80±6.75 (m, 1H), 6.65 (d, 1H, Jˆ7.7 Hz), 5.87±5.85
(m, 1H), 5.66 (s, 1H), 4.62 (d, 1H, Jˆ3.0 Hz), 4.13 (d,
1H, Jˆ8.5 Hz), 3.69 (brs, 1H), 3.03±2.93 (m, 1H), 2.65±
2.56 (m, 1H), 1.85±1.76 (m, 1H); 13C NMR (75 MHz,
CDCl3) d 145.2, 141.3, 133.9, 132.8, 130.2, 128.9, 127.9,
126.3, 125.9, 119.4, 115.9, 57.4, 46.2, 45.9, 31.3;MS m/z
281 (M1), 283 (M12);Anal. calcd for C 18H16ClN: C, 76.72;
H, 5.72;N, 4.97. Found: C, 76.56;H, 5.53;N, 4.91.
3.1.7. )4aa,5b,10ba)-3,4,4a,5,6,10b-Hexahydro-5-)4-chloro-
phenyl)-2H-pyrano[3,2-c]quinoline )3d). 0.395 g (53%)
of colourless solid, mp 168.4±1698C;IR (KBr) 3379,
1
2928, 1492, 1261 cm21; H NMR (300 MHz, CDCl3) d
7.35±7.26 (m, 5H), 7.21 (s, 1H), 6.76±6.62 (m, 1H), 6.54
(d, 1H, Jˆ8.1 Hz), 5.23 (d, 1H, Jˆ5.4 Hz), 4.84 (s, 1H),
3.91 (brs, 1H), 3.71 (d, 1H, Jˆ11.3 Hz), 3.64±3.43 (m,
3.1.12. 4-Phenyl-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]-
quinoline-4-carboxylic acid )7e). 0.604 g (83%) of colour-
less solid, mp 206±2078C;IR (KBr) 3349, 1608,

R. Nagarajan et al. / Tetrahedron 57 )2001) 3419±3423
3423
1
1491 cm21; H NMR (300 MHz, CDCl3) d 7.80 (d, 1H,
solid, mp 175±1768C;IR (KBr) 3386, 1679 cm 21; 1H NMR
(300 MHz, CDCl3) d 7.93±7.88 (m, 2H), 7.59±7.24 (m,
3H), 6.98±6.91 (m, 2H), 6.60 (d, 1H, Jˆ8.5 Hz), 5.68 (d,
1H, Jˆ2.6 Hz), 5.56 (s, 1H), 5.01 (d, 1H, Jˆ3.1 Hz), 4.46
(brs, 1H), 4.13 (d, 1H, Jˆ8.8 Hz), 3.34±3.23 (m, 1H), 2.40±
2.31 (m, 1H), 1.92±1.83 (m, 1H); 13C NMR (75 MHz,
CDCl3) d 198.8, 142.4, 135.3, 133.4, 130.1, 128.8, 128.4,
128.0, 127.4, 126.5, 123.2, 116.9, 59.5, 46.8, 42.3, 31.4;MS
m/z 309 (M1), 311 (M12);Anal. calcd for C 19H16ClNO: C,
73.69;H, 5.22;N, 4.46. Found: C, 83.09;H, 6.19;N, 5.16.
Jˆ8.0 Hz), 7.38 (m, 5H), 6.64 (m, 2H), 5.81 (m, 1H),
5.65 (m, 1H), 4.75 (d, 1H, Jˆ2.7 Hz), 4.48 (s, 1H), 4.13
(d, 1H, Jˆ8.4 Hz), 3.02 (m, 1H), 2.58 (m, 1H), 1.82 (m,
1H); 13C NMR (75 MHz, CDCl3) d 173.3, 150.2, 142.1,
135.5, 134.9, 130.6, 130.0, 128.6, 128.2, 127.1, 127.0,
126.8, 126.1, 116.2, 111.8, 56.4, 45.8, 45.3, 31.7;MS m/z
291 (M1);Anal. calcd for C 19H17NO2: C, 78.33;H, 5.88;N,
4.81. Found: C, 77.99;H, 5.86;N, 4.82.
3.1.13. 6,7-Dimethyl-4-phenyl-3a,4,5,9b-tetrahydro-3H-
cyclopenta[c]quinoline )7f). 0.536 g (78%) of pale yellow
3.1.18. 11-Nitro-6-phenyl-6,6a,7,9b-tetrahydro-5H-benzo-
[h]cyclopenta[c]quinoline )15). 0.612 g (92%) of brown
solid, mp 198.98C (d);IR (KBr) 3398, 1495 cm
1
solid, mp 114.5±114.68C;IR (KBr) 3384, 1469 cm 21; H
21
;
1H
NMR (300 MHz, CDCl3) d 7.62±7.40 (m, 5H), 6.97(d, 1H,
Jˆ7.5 Hz), 6.71 (d, 1H, Jˆ7.5 Hz), 5.98 (m, 1H), 5.79 (s,
1H), 4.65 (d, 1H, Jˆ2.7 Hz), 4.42 (d, 1H, Jˆ8.1 Hz), 3.80
(brs, 1H), 3.33±3.25 (m, 1H), 2.96±2.87 (m, 1H), 2.48 (s,
3H), 2.26 (s, 3H), 2.04±1.96 (m, 1H); 13C NMR (75 MHz,
CDCl3) d 144.8, 142.9, 134.2, 130.6, 128.4, 127.6, 126.4,
124.4, 120.5, 119.7, 58.5, 46.1, 45.6, 32.0, 19.5, 17.0;MS
m/z 275;Anal. calcd for C 20H21N: C, 87.23;H, 7.69;N,
5.09. Found: C, 87.36;H, 7.01;N, 4.99.
NMR (300 MHz, CDCl3) d 8.99 (d, 1H, Jˆ8.8 Hz), 8.41
(s, 1H), 7.72±7.60 (m, 2H), 7.49±7.44 (m, 1H), 5.90 (m,
1H), 5.74±5.72 (m, 1H), 5.54 (brs, 1H), 3.99 (s, 1H), 3.43±
3.37 (m, 1H), 3.06 (t, 1H), 2.77±2.73 (m, 2H), 2.20±2.15
(m, 1H); 13C NMR (75 MHz, CDCl3) d 147.5, 135.5, 130.1,
129.1, 126.3, 121.9, 119.8, 115.6, 46.2, 43.5, 37.0, 34.7;MS
m/z 266 (M1);Anal. calcd for C 16H14N2O2: C, 72.17;H,
5.30;N, 10.52. Found: C, 71.32;H, 5.49;N, 9.88.
3.1.14. )3aa,4b,9ba)-2,3,3a,4,5,9b-Tetrahydro-4-benzyl-
oxy-2H-furo[3,2-c]quinoline )11). 0.188 g (27%), dense
Acknowledgements
1
liquid;IR (neat) 3380, 1679 cm 21; H NMR (300 MHz,
CDCl3) d 7.92 (d, 1H, Jˆ7.5 Hz), 7.61±7.03 (m, 6H),
6.80±6.64 (m, 2H), 5.19 (d, 1H, Jˆ3.1 Hz), 5.12 (m, 1H),
3.94 (brs, 1H), 3.87±3.81 (m, 2H), 3.72±3.64 (m, 1H), 2.98
(m, 1H), 2.66±2.61 (m, 1H), 1.98±1.80 (m, 1H); 13C NMR
(75 MHz, CDCl3) d 198.7, 143.2, 134.0, 133.6, 133.4,
130.7, 128.9, 128.8, 128.6, 126.2, 120.4, 119.0, 115.5,
75.1, 65.5, 57.6, 38.7, 29.2;MS m/z 279 (M1).
We thank the Council of Scienti®c and Industrial Research,
New Delhi, India for ®nancial support.
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Tetrahedron
3.1.15. )3aa,4a,9ba)-2,3,3a,4,5,9b-Tetrahydro-4-benzyl-
oxy-2H-furo[3,2-c]quinoline )12). 0.349 g (50%) of
colourless solid, mp 149±1508C;IR (KBr) 3359,
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Khim.-
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1680 cm21; H NMR (300 MHz, CDCl3) d 8.09±7.98 (m,
2H), 7.61±7.07 (m, 5H), 6.82±6.77 (m, 1H), 6.64 (d, 1H,
Jˆ8.1 Hz), 4.67 (d, 1H, Jˆ5.5 Hz), 4.50 (d, 1H, Jˆ9.2 Hz),
4.24 (brs, 1H), 4.00±3.93 (m, 1H), 3.86±3.78 (m, 1H),
2.76±2.67 (m, 1H), 2.27±2.15 (m, 1H), 1.86±1.76 (m,
1H); 13C NMR (75 MHz, CDCl3) d 198.9, 143.4, 135.9,
133.8, 133.4, 130.8, 129.0, 128.9, 128.7, 126.1, 120.3,
119.0, 115.3, 75.1, 65.4, 57.4, 38.8, 29.3;MS m/z 255
(M1);Anal. calcd for C 18H17NO2: C, 77.40;H, 6.14;N,
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3.1.16. 4-Benzyloxy-3a,4,5,9b-tetrahydro-3H-cyclopen-
ta[c]quinoline )13a). 0.564 g (82%) of colourless solid,
mp 157±1588C;IR (KBr) 3384, 1681 cm
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therein).
21
;
1H NMR
8. Kametani, T.;Takeda, H.;Suzuki, Y.;Honda, T.
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Synth.
(300 MHz, CDCl3) d 7.93±7.85 (m, 2H), 7.60±7.47 (m,
3H), 7.06±6.98 (m, 2H), 6.76±6.67 (m, 2H), 5.73 (t, 1H),
5.56 (s, 1H), 5.05 (d, 1H, Jˆ3.1 Hz), 4.42 (brs, 1H), 4.21 (d,
1H, Jˆ8.9 Hz), 3.37±3.27 (m, 1H), 2.47±2.38 (m, 1H),
1.94±1.86 (m, 1H); 13C NMR (75 MHz, CDCl3) d 199.1,
143.9, 135.5, 133.9, 133.2, 129.5, 128.7, 128.0, 126.5,
125.8, 118.9, 115.8, 59.7, 46.9, 42.5, 31.4;MS m/z 309
(M1), 311 (M12);Anal. calcd for C 19H17NO: C, 82.88;
H, 6.22;N, 5.08. Found: C, 83.69;H, 6.19;N, 5.16.
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3.1.17. 8-Chloro-4-benzyloxy-3a,4,5,9b-tetrahydro-3H-
cyclopenta[c]quinoline )13b). 0.718 g (93%) of colourless
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Chem. 1988, 53, 2251±2258.
J. Org.