Studies on sequential Claisen rearrangement: Charge-accelerated [3,3]-sigmatropic rearrangement leading to polyheterocycles

Article abstract of DOI:10.1080/00397910701557812

A number of quinolone-annulated pentacycles have been regioselectively synthesized in 90-95% yields by sequential Claisen rearrangements. The second synthesis is anhydrous AlCl3-catalyzed charge-accelerated aromatic Claisen rearrangement of 1-aryloxymethy

Full text of DOI:10.1080/00397910701557812

This article was downloaded by: [RMIT University]
On: 06 September 2014, At: 11:42
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office:
Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An International
Journal for Rapid Communication of
Synthetic Organic Chemistry
Publication details, including instructions for authors and subscription
information:
http://www.tandfonline.com/loi/lsyc20
Studies on Sequential Claisen Rearrangement:
Charge‐Accelerated [3,3]‐Sigmatropic
Rearrangement Leading to Polyheterocycles
K. C. Majumdar a , D. Saha a & P. Debnath a
a Department of Chemistry , University of Kalyani , Kalyani, India
Published online: 05 Oct 2007.
To cite this article: K. C. Majumdar , D. Saha & P. Debnath (2007) Studies on Sequential Claisen
Rearrangement: Charge‐Accelerated [3,3]‐Sigmatropic Rearrangement Leading to Polyheterocycles, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry, 37:20,
3657-3665, DOI: 10.1080/00397910701557812
To link to this article: http://dx.doi.org/10.1080/00397910701557812
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”)
contained in the publications on our platform. However, Taylor & Francis, our agents, and our
licensors make no representations or warranties whatsoever as to the accuracy, completeness, or
suitability for any purpose of the Content. Any opinions and views expressed in this publication
are the opinions and views of the authors, and are not the views of or endorsed by Taylor &
Francis. The accuracy of the Content should not be relied upon and should be independently
verified with primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities
whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial
or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or
distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use
can be found at http://www.tandfonline.com/page/terms-and-conditions

Synthetic Communicationsw, 37: 3657–3665, 2007
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701557812
Studies on Sequential Claisen
Rearrangement: Charge-Accelerated [3,3]-
Sigmatropic Rearrangement Leading
to Polyheterocycles
K. C. Majumdar, D. Saha, and P. Debnath
Department of Chemistry, University of Kalyani, Kalyani, India
Abstract: A number of quinolone-annulated pentacycles have been regioselectively
synthesized in 90–95% yields by sequential Claisen rearrangements. The second
synthesis is anhydrous AlCl3-catalyzed charge-accelerated aromatic Claisen rearrangement
of 1-aryloxymethyl-6-alkyl-3H-pyrano[2,3-c]quinolin-5(6H)-ones in dichloromethane
at rt for 5–10 min. The precursors were synthesized by the thermal [3,3]-sigmatropic
rearrangement of the corresponding ethers.
Keywords: anhydrous aluminium chloride, Lewis acid–catalyzed Claisen rearrange-
ment, polyheterocycles, quinolone derivatives
INTRODUCTION
Several pyranoquinolones such as flindersine and its derivatives are widely dis-
tributed in nature[1] and are very important because of their pronounced biologi-
cal properties.[2] According to recent reports,[2] quinolone derivatives show
significant antibacterial activity, DNA-gyrase inhibition, and marked cyto-
toxicity against animal and plant tumors. Because of their biological and
medicinal importance, several methods for their synthesis have been
developed. Claisen rearrangement[3] is a preeminent methodology for the
construction of the C-C bond in organic synthesis with a high degree of regios-
electivity. In the course of our studies, we previously reported the synthesis of
Received March 22, 2007
Address correspondence to K. C. Majumdar, Department of Chemistry, University
of Kalyani, Kalyani 741 235, W.B., India. E-mail: kcm_ku@yahoo.co.in
3657

3658
K. C. Majumdar, D. Saha, and P. Debnath
several polyheterocycles by the application of sigmatropic rearrangement.[4]
Earlier we reported,[5] the regioselective synthesis of 3,4-fused furo- and
pyrano quinolones by [3,3]-sigmatropic rearrangement of the ethers of 3- and
4-hydroxy quinolones. Thermal rearrangement[6] required high temperature
and long time, so we attempted Lewis acid–catalyzed Claisen rearrangement.[7]
Among the different catalysts reported in the literature,[8] AlCl3 and its deriva-
tives are known to be efficient for Claisen rearrangement. We therefore became
interested in trying the reaction in the presence of anhydrous aluminium chloride
under mild conditions. Here we report the results.
RESULTS AND DISCUSSION
The requisite starting materials, 3-(40-aryloxybut-20-ynyloxy)-1-alkylquino-
lin-2(1H)-ones 3a–f, were synthesized in 75–88% yields by the classical
alkylation of 3-hydroxy-1-alkylquinolin-2(1H)-ones 1a,b with different
1-aryloxy-4-chlorobut-2-ynes 2a–d in refluxing dry acetone in the presence
of anhydrous potassium carbonate and a small amount of sodium iodide
(Finkelstein’s[9] condition) for 8–10 h (Scheme 1). The compounds 1a,b in
turn were prepared from 1-alkyl isatin and diazomethane by a slight modifi-
cation[10] of the published procedure.[11]
A thermal [3,3]-sigmatropic rearrangement of 3a–f was utilized for the
synthesis of 3H-pyranoquinolones 4a–f. Therefore, ethers 3a–f were
refluxed in chlorobenzene[5a] for 10–12 h to give 1-aryloxymethyl-5-alkyl-
3H-pyrano[2,3-c]quinolin-5(6H)-ones 4a–f in 90–95% yield (Scheme 2).
Compounds 4c–f were characterized from their elemental analyses and spec-
troscopic data. Compounds 4a–f contained an allyl aryl ether moiety
favorable for further [3,3]-sigmatropic rearrangement. This prompted us to
undertake a study on the Claisen rearrangement of compounds 4 for the
synthesis of polyheterocyclic compounds. Claisen rearrangement catalyzed
by Lewis acids[8] has been known to occur under mild conditions, giving
Scheme 1. Regards and conditions: (i) dry acetone, anhy. K2CO3, Nal, reflux, 8–10 h.

Sequential Claisen Rearrangement
3659
Scheme 2. Regents and conditions: (i) chlorobenzene, reflux, 10–12 h; (ii) anhy-
drous AlCl3, dry DCM, rt, 5–10 min.
excellent yields of products. When substrate 4a in dichloromethane was stirred
with anhydrous AlCl3 at room temperature for 8 min, we found that the reaction
was complete and afforded a white solid, mp 1828C in 92% yield. This was
1
characterized from its elemental analyses and spectroscopic data. H NMR
(500 MHz) spectra of 5a revealed dH ¼ 1.94 (s, 3H), 3.76 (s, 3H), 3.85 (dd,
1H, J ¼ 2 Hz, 12.9 Hz), 4.67 (dd, 1H, J ¼ 4.5 Hz, 13.1 Hz), 4.84 (dd, 1H,
J ¼ 2 Hz, 4.5 Hz), 6.73–8.31 (m, 8H). Mass spectrum of 5a showed a
molecular ion peak at m/z 319 (Mþ). Compounds 4b–f were similarly
treated to give the products 5b–f in 90–95% yields (Scheme 2).
The mechanistic rationalization for the formation of products 5a–f can be
explained by a series of steps involving an initial charge-accelerated [3,3]-
sigmatropic rearrangement. Substrates 4 can form an ether–AlCl3 complex
6 that may undergo [3,3]-sigmatropic rearrangement through a charge deloca-
lized transition state to give the intermediate 7 followed by rapid tautomerization
and proton exchange to give intermediates 9. These intermediates 9 undergo a
5-exo-cyclization to give the polyheterocyclic products 5 (Scheme 3).
In conclusion, we have demonstrated one oxy-Claisen rearrangement of
propynyl vinyl ether followed by a second oxy-Claisen rearrangement of
allyl aryl ether, which is run under mild conditions using Lewis acid–
catalyzed charge acceleration. This methodology is simple and straightforward
for the construction of the polyheterocyclic compounds in excellent yields.
EXPERIMENTAL
The melting points were recorded in open capillaries and are uncorrected. UV
absorption spectra were recorded in ethanol on a Shimadzv model no. UV-
2401PC spectrometer. IR spectra were run on KBr disks for solid samples
and neat for liquid samples on a Fourier transform infrared (FTIR) spectropho-
1
tometer, Perkin-Elmer model no. L 120-000A. H NMR spectra were deter-
mined for solutions in deuteriochloroform with TMS as internal standard on

3660
K. C. Majumdar, D. Saha, and P. Debnath
Scheme 3.
Brucker-DPX-300 (300 MHz) at Indian Institute of Chemical Biology (IICB)
(Kolkata) and Brucker-DRS-600 (500 MHz) spectrometers at Bose Institute
(Kolkata). Silica gel [(60–120 mesh), Spectrochem, India] was used for
chromatographic separation. Silica gel G [E Merck. (India)] was used.
Petroleum ether refers to the fraction boiling between 60 and 808C.
General Procedure for the Preparation of 3-(4-Arylbut-2-ynyloxy)-
1-alkylquinolin-2-ones 3a–f
The compounds 3-(4-arylbut-2-ynyloxy)-1-alkylquinolin-2-ones 3a–f were
prepared according to the earlier published[5a] procedure. Compounds 3a
and 3b were reported[5a] earlier.
Data
Compound 3c
Yield 88%; white solid, mp 1028C; UV (EtOH): lmax ¼ 224, 280, 333 nm; IR
(KBr): nmax ¼ 2920, 1715, 1590 cm21
;
1H NMR (CDCl3, 300 MHz):

Sequential Claisen Rearrangement
3661
dH ¼ 2.14 (s, 3H), 3.69 (s, 3H), 4.70 (t, 2H, J ¼ 1.5 Hz), 4.90 (t, 2H,
J ¼ 1.5 Hz), 6.92–7.34 (m, 8H); MS: m/z ¼ 367, 369 (Mþ). Anal. calcd.
for C21H18NO3Cl: C, 68.57; H, 4.93; N, 3.81%. Found: C, 68.81; H, 5.05;
N, 3.70%.
Compound 3d
Yield 88%; gummy mass, UV (EtOH): lmax ¼ 223, 282, 328 nm; IR (neat):
nmax ¼ 2922, 1720, 1596 cm21
;
1H NMR (CDCl3, 300 MHz): dH ¼ 1.01
(s, 9H), 3.68 (s, 3H), 4.68 (t, 2H, J ¼ 1.5 Hz), 4.89 (t, 2H, J ¼ 1.5 Hz),
6.90–7.32 (m, 9H); MS: m/z ¼ 375 (Mþ). Anal. calcd. for C24H25NO3: C,
76.77; H, 6.71; N, 3.73%. Found: C, 77.02; H, 6.81; N, 3.83%.
Compound 3e
Yield 85%; white solid, mp 688C; UV (EtOH): lmax ¼ 222, 281, 330 nm; IR
(KBr): nmax ¼ 2922, 1710, 1600 cm21
;
1H NMR (CDCl3, 300 MHz):
dH ¼ 1.39 (t, 3H, J ¼ 7 Hz), 3.79 (s, 3H), 4.46 (q, 2H, J ¼ 7 Hz), 4.67
(t, 2H, J ¼ 1.5 Hz), 4.88 (t, 2H, J ¼ 1.5 Hz), 6.92–7.28 (m, 9H); MS:
m/z ¼ 363, (Mþ). Anal. calcd. for C22H21NO4: C, 72.71; H, 5.82; N,
3.85%. Found: C, 72.83; H, 5.74; N, 3.79%.
Compound 3f
Yield 82%; white solid, mp 768C; UV (EtOH): lmax ¼ 223, 281, 332 nm; IR
(KBr): nmax ¼ 2922, 1715, 1620 cm21
;
1H NMR (CDCl3, 300 MHz):
dH ¼ 1.38 (t, 3H, J ¼ 7 Hz), 2.21 (s, 3H), 4.44 (q, 2H, J ¼ 7.1 Hz), 4.66
(t, 2H, J ¼ 1.5 Hz), 4.88 (t, 2H, J ¼ 1.5 Hz), 6.95–7.30 (m, 8H); MS:
m/z ¼ 381, 383 (Mþ). Anal. calcd. for C22H20NO3Cl: C, 69.20, H, 5.28, N,
3.67%. Found: C, 69.08; H, 5.39; N, 3.61%.
General Procedure for the Rearrangement of Compounds 3a–f
The rearrangement of compounds 3a–f were carried out according to the
earlier published[5a] procedure. Compounds 4a and 4b were reported[5a]
earlier.
Compound 4c
Yield 95%; white solid, mp 1868C; UV (EtOH): lmax ¼ 224, 320 nm; IR
(KBr): nmax ¼ 2920, 1680, 1590 cm21
;
1H NMR (CDCl3, 300 MHz):
dH ¼ 2.16 (s, 3H), 3.75 (s, 3H), 4.76 (d, 2H, J ¼ 4 Hz), 4.92 (s, 2H), 6.25
(t, 1H, J ¼ 4 Hz), 6.87–7.38 (m, 7H); MS: m/z ¼ 367, 369 (Mþ). Anal.

3662
K. C. Majumdar, D. Saha, and P. Debnath
calcd. for C21H18NO3Cl: C, 68.57; H, 4.93; N, 3.81%. Found: C, 68.80; H,
5.04; N, 3.88%.
Compound 4d
Yield 90%; gummy mass; UV (EtOH): lmax ¼ 225, 320 nm; IR (neat):
nmax ¼ 2920, 1665, 1600 cm21
;
1H NMR (CDCl3, 300 MHz): dH ¼ 1.05
(s, 9H), 3.79 (s, 3H), 4.77 (d, 2H, J ¼ 4 Hz), 4.91 (s, 2H), 6.21 (t, 1H,
J ¼ 4 Hz), 6.90–7.25 (m, 8H); MS: m/z ¼ 375, (Mþ). Anal. calcd. for
C24H25NO3: C, 76.77; H, 6.71; N, 3.73%. Found: C, 76.62; H, 6.84; N, 3.65%.
Compound 4e
Yield 92%; white solid, mp 1568C; UV (EtOH): lmax ¼ 224, 330 nm; IR
(KBr): nmax ¼ 2920, 1670, 1585 cm21
;
1H NMR (CDCl3, 300 MHz):
dH ¼ 1.39 (t, 3H, J ¼ 7 Hz), 3.76 (s, 3H), 4.47 (q, 2H, J ¼ 7 Hz), 4.78
(d, 2H, J ¼ 4 Hz), 4.90 (s, 2H), 6.27 (t, 1H, J ¼ 4 Hz), 6.92–7.53 (m, 8H);
MS: m/z ¼ 363, (Mþ). Anal. calcd. for C22H21NO4: C, 72.71; H, 5.82; N,
3.85%. Found: C, 72.88; H, 5.92; N, 3.74%.
Compound 4f
Yield 92%; white solid, mp 1308C; UV (EtOH): lmax ¼ 223, 333 nm; IR
(KBr): nmax ¼ 2920, 1665, 1580 cm21
;
1H NMR (CDCl3, 300 MHz):
dH ¼ 1.40 (t, 3H, J ¼ 6.9 Hz), 2.05 (s, 3H), 4.46 (q, 2H, J ¼ 7 Hz), 4.76
(d, 2H, J ¼ 4 Hz), 4.91 (s, 2H), 6.24 (t, 1H, J ¼ 4 Hz), 6.68–7.75 (m, 7H);
MS: m/z ¼ 381, 383 (Mþ). Anal. calcd. for C22H20NO3Cl: C, 69.20; H,
5.28; N, 3.67%. Found: C, 69.34; H, 5.19; N, 3.73%.
General Procedure for the Preparation of Compounds 5(a–f)
The compounds 4a–f (0.1 g) were dissolved in dry dichloromethane and
stirred at room temperature for 5–10 min in the presence of a catalytic
amount of anhydrous aluminium chloride. Then the reaction was decomposed
with ice water and extracted with dichloromethane (3 ꢀ 15 mL). Then the
dichloromethane layer was washed with water (3 ꢀ 10 mL) and brine
(1 ꢀ 10 mL) and then dried (Na2SO4). Dichloromethane was removed, and
the residual mass was chromatographed over silica gel. The products were
obtained in 90–95% yields when the column was eluted with pet ether–
ethyl acetate (4:1).

Sequential Claisen Rearrangement
3663
Data
Compound 5a
Yield 92%; white solid, mp 1828C; UV (EtOH): lmax ¼ 230, 252, 260 nm; IR
(KBr): nmax ¼ 2920, 1700, 1610 cm21
;
1H NMR (CDCl3, 500 MHz):
dH ¼ 1.94 (s, 3H), 3.76 (s, 3H), 3.85 (dd, 1H, J ¼ 2 Hz, 12.9 Hz), 4.67 (dd,
1H, J ¼ 4.5 Hz, 13.1 Hz), 4.84 (dd, 1H, J ¼ 2 Hz, 4.5 Hz), 6.73–8.31
(m, 8H); MS: m/z ¼ 319 (Mþ). Anal. calcd. for C20H17NO3: C, 75.22; H,
5.37; N, 4.39%. Found: C, 75.43; H, 5.30; N, 4.48%.
Compound 5b
Yield 93%; white solid, mp 1928C; UV (EtOH): lmax ¼ 229, 252, 265 nm; IR
(KBr): nmax ¼ 2920, 1705, 1600 cm21
;
1H NMR (CDCl3, 500 MHz):
dH ¼ 1.91 (s, 3H), 3.75 (s, 3H), 3.81 (s, 3H), 3.89 (dd, 1H, J ¼ 2 Hz,
13 Hz), 4.66 (dd, 1H, J ¼ 4.5 Hz, 13 Hz), 4.84 (dd, 1H, J ¼ 2 Hz, 4.5 Hz),
6.75–8.24 (m, 7H); MS: m/z ¼ 349, (Mþ). Anal. calcd. for C21H19NO4: C,
72.19; H, 5.48; N, 4.01%. Found: C, 72.35; H, 5.59; N, 4.09%.
Compound 5c
Yield 95%; white solid, mp 2028C; UV (EtOH): lmax ¼ 228, 250, 262 nm; IR
(KBr): nmax ¼ 2920, 1700, 1620 cm21
;
1H NMR (CDCl3, 500 MHz):
dH ¼ 1.92 (s, 3H), 2.16 (s, 3H), 3.76 (s, 3H), 3.85 (dd, 1H, J ¼ 2 Hz,
13 Hz), 4.69 (dd, 1H, J ¼ 4.5 Hz, 13 Hz), 4.86 (dd, 1H, J ¼ 2 Hz, 4.5 Hz),
6.75–8.16 (m, 6H); MS: m/z ¼ 367, 369 (Mþ). Anal. calcd. for
C21H18NO3Cl: C, 68.57; H, 4.93; N, 3.81%. Found: C, 68.43; H, 5.05; N,
3.88%.
Compound 5d
Yield 90%; white solid, mp 1708C; UV (EtOH): lmax ¼ 229, 251, 265 nm; IR
(KBr): nmax ¼ 2920, 1725, 1630 cm21
;
1H NMR (CDCl3, 500 MHz):
dH ¼ 1.08 (s, 9H), 1.88 (s, 3H), 3.77 (s, 3H), 3.81 (dd, 1H, J ¼ 2 Hz,
13 Hz), 4.67 (dd, 1H, J ¼ 4.5 Hz, 13 Hz), 4.85 (dd, 1H, J ¼ 2 Hz, 4.5 Hz),
6.79–8.32 (m, 7H); MS: m/z ¼ 375, (Mþ). Anal. calcd. for C24H25NO3: C,
76.77; H, 6.71; N, 3.73%. Found: C, 76.99; H, 6.78; N, 3.81%.
Compound 5e
Yield 92%; white solid, mp 1988C; UV (EtOH): lmax ¼ 230, 251, 260 nm; IR
(KBr): nmax ¼ 2920, 1720, 1625 cm21
;
1H NMR (CDCl3, 500 MHz):
dH ¼ 1.38 (t, 3H, J ¼ 7 Hz), 1.91 (s, 3H), 3.80 (s, 3H), 3.89 (dd, 1H,
J ¼ 2 Hz, 13 Hz), 4.45 (q, 2H, J ¼ 7 Hz), 4.65 (dd, 1H, J ¼ 4.5 Hz, 13 Hz),

3664
K. C. Majumdar, D. Saha, and P. Debnath
4.82 (dd, 1H, J ¼ 2 Hz, 4.5 Hz), 6.80–8.01 (m, 7H); MS: m/z ¼ 363, (Mþ).
Anal. calcd. for C22H21NO4: C, 72.71; H, 5.82; N, 3.85%. Found: C, 72.89; H,
5.87; N, 3.78%.
Compound 5f
Yield 95%; white solid, mp 2068C; UV (EtOH): lmax ¼ 228, 252, 260 nm; IR
(KBr): nmax ¼ 2920, 1715, 1610 cm21
;
1H NMR (CDCl3, 500 MHz):
dH ¼ 1.39 (t, 3H, J ¼ 7 Hz), 1.91 (s, 3H), 2.12 (s, 3H), 3.84 (dd, 1H,
J ¼ 2 Hz, 13 Hz), 4.45 (q, 2H, J ¼ 7 Hz), 4.68 (dd, 1H, J ¼ 4.5 Hz, 13 Hz),
4.85 (dd, 1H, J ¼ 2.1 Hz, 4.5 Hz), 6.85–8.24 (m, 6H); MS: m/z ¼ 381,
383 (Mþ). Anal. calcd. for C22H20NO3Cl: C, 69.20; H, 5.28; N, 3.67%.
Found: C, 69.46; H, 5.40; N, 3.75%.
ACKNOWLEDGMENT
We thank the Council of Scientific and Industrial Research (CSIR) (New
Delhi) for financial assistance. Two of us (D. S. and P. D.) are grateful to
the CSIR for senior research fellowships. We also thank the Department of
Science and Technology (DST) (New Delhi) for providing UV-vis and IR
spectrometers under the DST-Financial Assistance for Infrastructural Deve-
lopment of Science and Technology (FIST) Program.
REFERENCES
1. Jurd, L.; Benson, M. Structures of paraensidimerins B, E, F, and G, four new
dimeric quinolone alkaloids from Euxylophora paraensis. J. Chem. Soc., Chem.
Commun. 1983, 92.
2. (a) Hagen, S. E.; Domagala, J. M.; Heifetz, C. L.; Sanchez, J. P.; Solomon, M. New
quinolone antibacterial agents: Synthesis and biological activity of 7-(3,3 or 3,4-
disubstituted-1-pyrrolidinyl) quinoline-3-carboxylic acids. J. Med. Chem. 1990,
33 (2), 849; (b) Laborde, E.; Kiely, J. S.; Culbertson, T. P.; Lesheski, L. E.
Quinolone antibacterials: Synthesis and biological activity of carbon isosteres of
the 1-piperazinyl and 3-amino-1-pyrolidinyl side chains. J. Med. Chem. 1993,
´
36 (14), 1964; (c) Gozalbes, R.; Brun-pascaud, M.; Garcıa-Domenech, R.;
Galvez, J.; Girard, P.; Doucet, J.; Derouin, F. Prediction of quinolone activity
´
against Mycobacterium avium by molecular topology and virtual computational
screening. Antimicrobial Agents and Chemotherapy 2000, 44, 2764;
(d) Lawrence, L. E.; Wu, P.; Fan, L.; Gouveia, K. E.; Card, A.; Casperson, M.;
Denbleyker, K.; Barrett, J. F. The inhibition and selectivity of bacterial topoiso-
merases by BMS-284756 and its analogues. Journal of Antimicrobial Chemotherapy
2001, 48, 195; (e) Brighty, K. E.; Gootz, T. D. The chemistry and biological profile
of trovafloxacin. Journal of Antimicrobial Chemotherapy 1997, 39, 1;
(f) Neville, C. F.; Grundon, M. F.; Ramchandran, V. N.; Reisch, G.; Reisch, J.

Sequential Claisen Rearrangement
3665
Quinoline alkaloids. Part-28. The biosynthesis of furoquinolines and other hemi-
terpenoids in Ptelea trifoliata. J. Chem. Soc. Perkin Trans. 1 1991, 2261.
3. (a) Castro, A. M. M. Claisen rearrangement over the past-nine decades. Chem. Rev.
2004, 104, 2939; (b) Blechert, S. The hetero-cope rearrangement in organic
synthesis. Synthesis 1989, 71; (c) Ziegler, F. E. The thermal, aliphatic Claisen
rearrangement. Chem. Rev. 1988, 88, 1423.
4. (a) Majumdar, K. C.; Ghosh, M.; Jana, M.; Saha, D. Facile regioselective synthesis
of 2(H)-thiopyrano[3,2-c]quinoline-5(6H)-ones by Thio-Claisen rearrangement of
propargyl thio[1]benzopyran-2-ones. Tetrahedron Lett. 2002, 43, 2111;
(b) Majumdar, K. C.; Kundu, U. K.; Ghsoh, S. K. Studies in sigmatropic rearrange-
ment: Synthesis of [6,6] pyranothiopyran ring system by sequential claisen
rearrangement and pyridine hydrotribromide mediated regioselective ‘6-endo’
cyclization. Org. Lett. 2002, 4, 2629; (c) Majumdar, K. C.; Ghosh, S. K. Studies
of bioactive heterocycles: Facile Thio-Claisen rearrangement of propargyl thio[1]-
benzopyran-2-ones. Tetrahedron Lett. 2002, 43, 2115.
5. (a) Majumdar, K. C.; Kundu, A. K. Studies in sigmatropic rearrangement of 3-(4-
aryloxybut-2-ynyloxy)-1-methyl quinolin-2-ones: Synthesis of 3H-pyrano[2,3-
c]quinolin-5(6H)-ones and furo[2.3-c]quinolin-4(5H)-ones. Heterocycles 1997,
45 (8), 1467; (b) Majumdar, K. C.; Kundu, A. K.; Chatterjee, P. Studies in [3,3]
sigmatropic rearrangement: Facile regioselective synthesis of furo-[2,3-
c]quinolin-4(5H)-ones and pyrano[2.3-c]quinolin-5(6H)-ones. J. Chem. Res. (S)
1995, 387.
6. (a) Majumdar, K. C.; Das, U. Studies in pyrimidine-annelated heterocycles by
tandem cyclisation: Regioselective synthesis of [6,6] pyranopyran by internal
[1,6] Michael addition. J. Org. Chem. 1998, 63, 9997; (b) Majumdar, K. C.;
Chatterjee, P.; Saha, S. Regioselective synthesis of [6c,12b-cis]-6c,7,12,13-tetra-
hydro-1H-Chromeno[3 ¼ B4, 4 ¼ B4: 4,5]pyrano[2,3-c]Chromeno-1-ones via
[1, 6] Michael addition. Tetrahedron Lett. 1998, 39, 7147.
7. (a) Majumdar, K. C.; Chattopadhyay, S. K. Synthesis of pyrimidine annulated
heterocycles: An efficient sequential and tandem catalyzed Claisen rearrangement–
intramolecular hydroaryloxylation approach to furothiopyran system. Can. J.
Chem. 2006, 84, 469; (b) Majumdar, K. C.; Alam, S. Regioselective Synthesis
of
7-acetyl-11c-methyl-4b,5,7,11c-tetrahydro[1]benzofuro[2/,3/:4,5]thiopyr-
ano[2,3-b]indoles by sequential Claisen Rearrangement of 2-(4/-aryloxybut-2/-
ynylthio)-1-acetylindoles. J. Chem. Res. 2006, 285.
8. (a) Lutz, R. P. Catalysis of the cope and Claisen rearrangements. Chem. Rev. 1984,
84, 205; (b) Bates, D. K.; Janes, M. W. Acid Catalysts of the Claisen Rearrange-
ment. 2. Formation of the benzofurobenzopyran and benzofuro[3,2-b]benzofuran
skeletons from 1,4-bis(aryloxy)-2-butynes. J. Org. Chem. 1978, 43, 3856;
(c) Borgulya, J.; Madeja, R.; Fahrni, P.; Hansen, H. J.; Schmid, H.; Barner, R.
Umlagerung Von Allyl-arylathern und Allyl-cyclohexadienonen mittels Bortri-
chlorid. Helv. Chim. Acta 1973, 56, 14.
9. (a) Gazith, M.; Noyes, R. M. Kinetics of the thermal and photochemical Exchange
between benzyl iodine and iodine. J. Am. Chem. Soc. 1955, 77, 6091;
(b) Gardner, I. J.; Noyes, R. M. Effects of substituents on the radical exchange
reaction between benzyl iodide and iodide. ibid 1961, 83, 2409.
10. Majumdar, K. C.; Kundu, A. K. Regioselective synthesis of polyheterocycles from
4-cyclohex-2-enyl-3-hydroxy-1-methylquinoline-2(1H)-one. Synth. Commun.
1996, 26, 4023.
11. Ault, R. G.; Hirst, E. L.; Morton, R. A. Absorption spectra in relation to the con-
stitution of derivaties of isation and carbostyril. J. Chem. Soc. 1935, 1653.