One-pot synthesis of highly functionalized stable ketenimines by three-component reaction of cyclohexyl isocyanide, dialkyl acetylenedicarboxylates, and benzoyl hydrazones

Article abstract of DOI:10.1080/00397910802406711

The adduct produced in the reaction between cyclohexyl isocyanide and dialkyl acetylenedicarboxylates was trapped by benzoyl hydrazones to afford highly functionalized ketenimines in good yields. The reaction is characterized by mild conditions, high sele

Full text of DOI:10.1080/00397910802406711

This article was downloaded by: [Georgetown University]
On: 05 August 2013, At: 12:06
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
One-Pot Synthesis of Highly
Functionalized Stable
Ketenimines by Three-
Component Reaction of
Cyclohexyl Isocyanide, Dialkyl
Acetylenedicarboxylates, and
Benzoyl Hydrazones
Mohammad Anary-Abbasinejad a , Fatemeh Ghanea a
& Hossein Anaraki-Ardakani b
a Department of Chemistry, Islamic Azad University,
Yazd Branch, Yazd, Iran
b Department of Chemistry, Islamic Azad University,
Mahshahr Branch, Mahshahr, Iran
Published online: 08 Jan 2009.
To cite this article: Mohammad Anary-Abbasinejad , Fatemeh Ghanea & Hossein
Anaraki-Ardakani (2009) One-Pot Synthesis of Highly Functionalized Stable
Ketenimines by Three-Component Reaction of Cyclohexyl Isocyanide, Dialkyl
Acetylenedicarboxylates, and Benzoyl Hydrazones, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 39:3,
544-551, DOI: 10.1080/00397910802406711
To link to this article: http://dx.doi.org/10.1080/00397910802406711

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 Communications1, 39: 544–551, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802406711
One-Pot Synthesis of Highly Functionalized
Stable Ketenimines by Three-Component
Reaction of Cyclohexyl Isocyanide, Dialkyl
Acetylenedicarboxylates, and
Benzoyl Hydrazones
Mohammad Anary-Abbasinejad,1 Fatemeh Ghanea,1
and Hossein Anaraki-Ardakani2
1Department of Chemistry, Islamic Azad University, Yazd Branch,
Yazd, Iran
2Department of Chemistry, Islamic Azad University, Mahshahr Branch,
Mahshahr, Iran
Abstract: The adduct produced in the reaction between cyclohexyl isocyanide and
dialkyl acetylenedicarboxylates was trapped by benzoyl hydrazones to afford
highly functionalized ketenimines in good yields. The reaction is characterized
by mild conditions, high selectivity, and tolerance to various functional groups.
Keywords: Acetylenic esters, benzoyl hydrazones, isocyanides, ketenimines, NH
acids, three-component reaction
Multicomponent reactions (MCRs), by virtue of their convergence, pro-
ductivity, facile execution, and generally high yields of products, have
attracted much attention from the point of view of combinatorial chem-
istry. Of pivotal importance in this area are the isocyanide-based MCRs
such as the versatile Ugi and Passerini reactions.[1–3] In recent years, the
synthetic applications of multifunctional heteroallenes have been widely
Received June 28, 2008.
Address correspondence to Mohammad Anary-Abbasinejad, Department of
Chemistry, Islamic Azad University, Yazd Branch, P.O. Box 89195-155, Yazd,
Iran. E-mail: mohammadanary@yahoo.com
544

Highly Functionalized Stable Ketenimines
545
investigated.[4,5] In spite of extensive developments in the chemistry of
modified ketenes and isocyanates,[6] little attention has been paid to the
synthesis of ketenimines.[7] Ketenimines are important reactive intermedi-
ates that occur as transient compounds in many thermal and photo-
chemical reactions.[8,9] There has been intense interest in their addition
reactions, such as cycloaddition,[10] and nucleophilic[9b,c,11] and electro-
philic[12] addition.
The trapping of the 1:1 intermediate formed between dialkyl acetylene-
dicarboxylatesandisocyanideswithOH, NH, andCHacidshasbeenwidely
studied.[13–18] In continuation of our work on the reaction between isocya-
nides and acetylenic esters in the presence of organic acids,[19–21] here we
report the results of our studies on the reaction between cyclohexyl isocya-
nide and dialkyl acetylenedicarboxylates, in the presence of benzoyl hydra-
zones of aromatic aldehydes. Thus, cyclohexyl isocyanide 1 and dialkyl
acetylenedicarboxylates 2 in the presence of benzoyl hydrazones 3 undergo
a smooth 1:1:1 addition reaction in acetone at ambient temperature to pro-
duce dialkyl 2-(N-benzoyl-N0-benzylidene-hydrazino)-3-cyclohexylimino-
methylene-succinate derivatives 4a–e in excellent yields (Scheme 1).
The structures of compounds 4a–e were deduced from their elemental
analyses and their IR, 1H NMR, and 13C NMR spectra. The mass
spectrum of 4a displayed the molecular ion peak at m=z ¼ 520, which is
consistent with the formation of a 1:1:1 adduct of dimethyl acetylene-
dicarboxylate, cyclohexyl isocyanide, and P-nitro benzaldehyde benzoyl
hydrazone. The IR spectra of the ketenimines exhibit a strong absorption
band at about 2030 cmꢀ1. The IR spectrum of 4a exhibited the absorption
Scheme 1. Three-component reaction of cyclohexyl isocyanide, dialkyl acetylene-
dicarboxylates, and benzoyl hydrazones.

546
M. Anary-Abbasinejad, F. Ghanea, and H. Anaraki-Ardakani
band for the ketenimine moiety at 2065 cmꢀ1 and for the ester carbonyl
groups at 1744 and 1699 cmꢀ1
.
The 1H NMR spectrum of compound 4a exhibited three sharp singlet
signals readily recognized as arising from methoxy (d ¼ 3.70 and 3.74)
and CH (d ¼ 5.83) protons. The NCH proton appeared as a multiplet
at 3.89 ppm, and the signals related to methylene groups of cyclohexyl
moiety were observed as multiplets at 1.21–1.99 ppm.
The protons of the aryl group exhibited characteristic signals in the aro-
matic region of the spectrum. A single signal was observed at 8.24ppm,
which arises from the N ¼ CH proton. The 13C NMR spectrum of com-
pound 4a showed 21 distinct resonances in agreement with the proposed
structure. The sp2-hybridized carbon atom of the ketenimine residue
appears at d ¼ 58.36 ppm, as a result of strong electron delocalization. Par-
tial assignments of these resonances are given in the experimental section.
Although we have not established the mechanism of the reaction
between an isocyanide and an acetylenic ester in the presence of benzoyl
hydrazones 3 experimentally, a possible explanation is proposed in
Scheme 2. On the basis of the well-established chemistry of isocya-
nides,[1,3,22–24] it is reasonable to assume that the functionalized keteni-
mine 4 results from the initial addition of the isocyanide to the
acetylenic ester and subsequent protonation of the 1:1 adduct 5 by ben-
zoyl hydrazones. Then, the positively charged ion 6 is attacked by anion
7 to give the product 4 (Scheme 2).
In summary, the simple one-pot reaction between cyclohexyl isocya-
nide and dialkyl acetylenedicarboxylates in the presence of benzoyl
hydrazones provides access to stable ketenimine derivatives of potential
synthetic interest. The presented method has the advantage of being
performed under neutral conditions and requires no activation or modi-
fication of the reagents.
EXPERIMENTAL
Melting points were determined with an electrothermal 9100 apparatus.
Elemental analyses were performed using a Heraeus CHN-O-Rapid
Scheme 2. Suggested mechanism for formation of compound 4.

Highly Functionalized Stable Ketenimines
547
analyzer. Mass spectra were recorded on a Finnigan-MAT 8430 mass
spectrometer operating at an ionization potential of 70 eV. IR spectra
1
were recorded on a Shimadzu IR-470 spectrometer. H and 13C NMR
spectra were recorded on Bruker DRX-500 Avance spectrometer at solu-
tion in CDCl3 using TMS as internal standard. The chemicals used in this
work were purchased from Fluka (Buchs, Switzerland) and were used
without further purification.
General Procedure
To a magnetically stirred solution of dialkyl acetylenedicarboxylate
(2 mmol) and benzoyl hydrazone (2 mmol) in acetone (10 mL), a solution
of cyclohexyl isocyanide (2 mmol) in acetone (5 mL) was added dropwise
at rt over 10 min. The mixture was then allowed to stir for 24 h. The sol-
vent was removed under reduced pressure, and the residue was separated
by column chromatography (silica gel, hexane–EtOAc, 5:1) to afford the
pure title compounds.
Data
Dimethyl-2-[N-benzoyl-N0-(4-nitro-benzylidene)-hydrazino]-3-cyclohexy-
liminomethylene-succinate (4a)
Yellow oil; yield 0.94 g (91%); IR (KBr) (nmax, cmꢀ1): 2065 (N ¼ C ¼ C),
1744, 1699 (C ¼ O, ester). Analyses: calcd. for C27H28N4O7: C, 62.30; H,
5.42; N, 10.76%. Found: C, 62.35; H, 5.40; N, 10.80%. MS (m=z, %): 520
(Mþ, 6). 1H NMR (500.1 MHz, CDCl3): d ¼ 1.22–1.99 (10 H, m, 5 CH2 of
cyclohexyl), 3.70 (3 H, s, OCH3), 3.74 (3 H, s, OCH3), 3.89 (1 H, m, CH
of cyclohexyl), 5.83 (1 H, s, CH), 7.37–8.13 (9 H, m, aromatic), 8.24 (1 H,
s, N ¼ CH) ppm. 13C NMR (125.7MHz, CDCl3): 24.28, 25.61, and 33.42
(5 CH2 of cyclohexyl), 52.14 (OCH3), 53.35 (OCH3), 54.87 (CH of cyclo-
hexyl), 58.36 (N ¼ C ¼ C), 60.88 (CH), 124.07, 127.99, 128.33, 130.16,
131.40, 134.58, 139.07, and 141.15 (C aromatic), 148.50 (N ¼ CH), 161.34
(N ¼ C ¼ C), 168.09 (COPh), 171.18 (CO2Me), 171.36 (CO2Me) ppm.
Dimethyl-2-[N-benzoyl-N0-(4-methoxy-benzylidene)-hydrazino]-3-cyclo-
hexyliminomethylene-succinate (4b)
Yellow oil; yield 0.90 g (90%); IR (KBr) (nmax, cmꢀ1): 2063 (N ¼ C ¼ C),
1744, 1699 (C ¼ O, ester). Analyses: calcd. for C28H31N3O6: C, 66.52; H,

548
M. Anary-Abbasinejad, F. Ghanea, and H. Anaraki-Ardakani
6.18; N, 8.31%. Found: C, 66.61; H, 6.10; N, 8.39%. MS (m=z, %): 505
1
(Mþ, 2). H NMR (500.1 MHz, CDCl3): d ¼ 1.24–1.90 (10 H, m, 5 CH2
of cyclohexyl), 3.72 (3 H, s, OCH3), 3.75 (3 H, s, OCH3), 3.78 (3 H, s,
OCH3), 3.82 (1 H, m, CH of cyclohexyl), 5.79 (1 H, s, CH), 6.82–7.37
(9 H, m, aromatic), 8.12 (1 H, s, N ¼ CH) ppm. 13C NMR (125.7 MHz,
CDCl3): d ¼ 23.99, 25.17, and 33.02 (5 CH2 of cyclohexyl), 51.68
(OCH3), 52.97 (OCH3), 54.79 (CH of cyclohexyl), 55.29 (OCH3), 58.66
(N ¼ C ¼ C), 60.49 (CH), 114.06, 113.96, 127.23, 127.40, 129.80, 129.80,
130.53, and 134.64 (C aromatic), 149.22 (N ¼ CH), 161.04 (N ¼ C ¼ C),
168.26 (COPh), 170.45 (CO2Me), 170.63 (CO2Me) ppm.
Diethyl-2-[N-benzoyl-N0-(4-chloro-benzylidene)-hydrazino]-3-cyclohexy-
liminomethylene-succinate (4c)
Yellow oil; yield 0.95 g (89%); IR (KBr) (nmax, cmꢀ1): 2075 (N ¼ C ¼ C),
1724, 1691 (C ¼ O, ester). Analyses: calcd. for C29H32ClN3O5: C, 64.74;
H, 5.99; N, 7.81%. Found: C, 64.70; H, 6.02; N, 7.85%. MS (m=z, %):
537 (Mþ, 7). 1H NMR (500.1 MHz, CDCl3): d ¼ 1.24 (6 H,m,
2OCH2CH3), 1.26–2.06 (10 H, m, 5 CH2 of cyclohexyl), 3.91 (1 H, m,
CH of cyclohexyl), 4.18–4.27 (4 H, m, 2OCH2CH3), 5.78 (1 H, s, CH),
7.28–7.72 (9 H, m, aromatic), 8.17 (1 H, s, N ¼ CH) ppm. 13C NMR
(125.7 MHz, CDCl3): d ¼ 14.58 (OCH2CH3),14.83 (OCH2CH3), 24.13,
25.66, and 33.37 (5 CH2 of cyclohexyl), 54.94 (CH of cyclohexyl), 59.09
(N ¼ C ¼ C), 60.76 (OCH2CH3), 60.84 (OCH2CH3), 62.50 (CH),
127.87, 129.03, 129.26, 130.02, 130.98, 133.62, 135.09, and 135.90
(C aromatic), 142.50 (N ¼ CH), 163.15 (N ¼ C ¼ C), 167.83 (COPh),
170.77 (CO2Et), 171.13 (CO2Et) ppm.
Dimethyl-2-(N-benzoyl-N0-benzylidene-hydrazino)-3-cyclohexylimino-
methylene-succinate (4d)
Yellow oil; yield 0.87 g (92%); IR (KBr) (nmax, cmꢀ1): 2110 (N ¼ C ¼ C),
1752, 1667 (C ¼ O, ester). Analyses: calcd. for C27H29N3O5: C, 68.19; H,
6.15; N, 8.84%. Found: 68.21; H, 6.12; N, 8.79%. MS (m=z, %): 475 (Mþ,
1
2). H NMR (500.1 MHz, CDCl3): d ¼ 1.26–2.04 (10 H, m, 5 CH2 of
cyclohexyl), 3.73 (3 H, s, OCH3), 3.83 (3 H, s, OCH3), 3.91 (1 H, m,
CH of cyclohexyl), 5.80 (1 H, s, CH), 7.27–7.74 (10 H, m, aromatic),
8.15 (1 H, s, N ¼ CH) ppm. 13C NMR (125.7 MHz, CDCl3): d ¼ 23.92,
25.20, and 33.04 (5 CH2 of cyclohexyl), 51.74 (OCH3), 53.07 (OCH3),
54.96 (CH of cyclohexyl), 58.32 (N ¼ C ¼ C), 60.50 (CH), 127.48,
128.67, 128.89, 129.81, 130.74, 133.13, 134.42, and 135.58 (C aromatic),

Highly Functionalized Stable Ketenimines
549
149.62 (N ¼ CH), 162.45 (N ¼ C ¼ C), 168.05 (COPh), 170.71 (CO2Me),
170.75 (CO2Me) ppm.
Dimethyl-2-[N-benzoyl-N0-(4-chloro-benzylidene)-hydrazino]-3-cyclo-
hexyliminomethylene-succinate (4e)
Yellow oil; yield 0.90 g (89%); IR (KBr) (nmax, cmꢀ1): 2070 (N ¼ C ¼ C),
1747, 1691 (C ¼ O, ester). Analyses: calcd. for C27H28ClN3O5: C, 63.59;
H, 5.53; N, 8.24%. Found: C, 63.63; H, 5.50; N, 8.35%. MS (m=z, %):
1
509 (Mþ, 4). H NMR (500.1 MHz, CDCl3): d ¼ 1.27–2.03 (10 H, m, 5
CH2 of cyclohexyl), 3.74 (3 H, s, OCH3), 3.81 (3 H, s, OCH3), 3.91 (1
H, m, CH of cyclohexyl), 5.85 (1 H, s, CH), 7.31–7.77 (9 H, m, aromatic),
8.18 (1 H, s, N ¼ CH) ppm. 13C NMR (125.7 MHz, CDCl3): d ¼ 23.92,
25.19, and 33.04 (5 CH2 of cyclohexyl), 51.72 (OCH3), 53.02 (OCH3),
54.26 (CH of cyclohexyl), 58.52 (N ¼ C ¼ C), 60.51 (CH), 127.45,
127.54, 128.63, 129.83, 129.89, 130.67, 134.52, and 135.23 (C aromatic),
146.52 (N ¼ CH), 162.29 (N ¼ C ¼ C), 168.14 (COPh), 170.66 (CO2Me),
170.69 (CO2Me) ppm.
REFERENCES
1. Ugi, I. From isocyanides via four-component condensations to antibiotic
syntheses. Angew. Chem., Int. Ed. Eng. 1982, 21, 810.
2. Ugi, I.; Lohberger, S.; Karl, R. In Comprehensive Organic Synthesis; B. M.
Trost, I. Fleming, (Eds.); Pergamon: Oxford, 1991; vol. 2, p. 1083.
3. Domling, A.; Ugi, I. Multicomponent reactions with isocyanides. Angew.
Chem., Int. Ed. Eng. 2000, 39, 3169.
4. Reichen, W. Oxygen-, nitrogen-, and sulfur-substituted heteroallenes. Chem.
Rev. 1978, 78, 569.
5. Motoyoshiya, J.; Teranishi, A.; Mikoshiba, R.; Yamamoto, I.; Gotoh, H.
C-Phosphonoketenimines: Characterization, and synthetic application to
heterocycles. J. Org. Chem. 1980, 45, 5385.
6. Ishida, M.; Minami, T.; Agawa, T. Synthetic application of methyl (phe-
nylthio) ketene: Synthesis of vicinal-substituted cyclopentene derivaties.
J. Org. Chem. 1979, 44, 2067.
7. Krow, G. Synthesis and reaction of ketenimines. Angew. Chem., Int. Ed. Eng.
1971, 10, 435.
8. (a) Tidwell, T. T. Ketenes; Wiley: New York, 1995; (b) Barker, M. W.;
McHenry, W. E. The Chemistry of Ketenes, Allenes, and Related Compounds,
Part 2; Wiley: New York, 1980.
9. (a) Tidwell, T. T. Ketene chemistry: The second golden age. Acc. Chem.
Res. 1990, 23, 273; (b) Chiang, Y.; Grant, A. S.; Guo, H.-X.; Kresge, A. J.;
Paine, S. W. Flash photolytic decarbonylation and ring-opening of

550
M. Anary-Abbasinejad, F. Ghanea, and H. Anaraki-Ardakani
2-(N-(pentafluorophenyl)amino)-3-phenylcyclopropenone: Isomerization of
the resulting ynamine to a ketenimine, hydration of the ketenimine, and
hydrolysis of the enamine produced by ring-opening. J. Org Chem. 1997,
62, 5363; (c) Ye, T.; McKervey, M. A. Organic Synthesis with a-diazo carbo-
nyl compounds. Chem. Rev. 1994, 94, 1091; (d) Birney, D. B.; Xu, X.; Ham, S.;
Huang, X. Chemoselectivity in the reactions of acetylketene and acetimidoylk-
etene: Confirmation of theoretical predictions. J. Org Chem. 1997, 62, 7114;
(e) Wagner, B. D.; Arnold, B. R.; Brown, G. S.; Lusztyk, J. Spectroscopy
and absolute reactivity of ketenes in acetonitrile studied by laser flash photo-
lysis with time-resolved infrared detection. J. Am. Chem. Soc. 1998, 120, 1827.
10. (a) Schmittel, M.; Steffen, J. P.; Angel, M. A. W.; Engels, B.; Lennartz, C.;
Hanrath, M. Two novel thermal biradical cyclizations of enyne-ketenimines:
Theory, experiment, and synthetic potential. Angew. Chem. Int. Ed. 1998, 37,
1562; (b) Alajarin, M.; Vidal, A.; Tovar, F.; Arellano, M. C. R. Stereocon-
trolled synthesis of azeto[2,1-b] quinazolines bearing three stereocenters via
the intramolecular [2 þ 2] cycloaddition between ketenimines and imines.
Tetrahedron: Asymmetry 2004, 15, 489; (c) Calter, M. A. Catalytic, asym-
metric dimerization of methylketene. J. Org. Chem. 1996, 61, 8006.
11. (a) Qiao, G. G. H.; Andraos, J.; Wentrup, C. Reactivity of ketenes in
matrices: Direct observation of ketene-pyridine ylides. J. Am. Chem. Soc.
1996, 118, 5634; (b) Sung, K.; Tidwell, T. T. Amination of ketene: A theore-
tical study. J. Am. Chem. Soc. 1998, 120, 3043; (c) Annette, D. A.; Tidwell, T.
T. Kinetics and mechanism of hydration of alkyl ketenes. J. Am. Chem. Soc.
1987, 109, 2774; (d) Acton, A. W.; Allen, A. D.; Antunes, L. M.; Fedorov, A.
V.; Najafian, K.; Tidwell, T. T.; Wagner, B. D. Amination of pyridylketenes:
experimental and computational studies of strong amide enol stabilization by
the 2-pyridyl group. J. Am. Chem. Soc. 2002, 124, 13790.
12. (a) Fromont, C.; Masson, S.; Reactivity of N-phenyl silylated ketenimines
with electrophilic reagents. Tetrahedron 1999, 55, 5405; (b) Pietri, N.; Chia-
vassa, T.; Allouche, A.; Aycard, J. P. IR structural identification of oxocumu-
lene HCl complexes generated in cryogenic matrixes: The product-like
transition state of the corresponding electrophilic addition. J. Phys. Chem.
A. 1997, 101, 1093.
13. Shaabani, A.; Soleimani, E.; Khavasi, H. R.; Hoffmann, R. D.; Rodewald,
U. C.; Po¨ttgen, R. An isocyanide-based three-component reaction: Synthesis
of fully substituted N-alkyl-2-triphenylphosphoranylidene glutarimides.
Tetrahedron Lett. 2006, 47, 5493.
14. Yavari, I.; Anary-Abbasinejad, M.; Alizadeh, A.; Hossaini, Z. A simple and
efficient approach to the synthesis of highly functionalized fused benzochro-
menes. Tetrahedron 2003, 59, 1289.
15. Yavari, I.; Zare, H.; Mohtat, B. Three-component synthesis of dialkyl
2-(alkylimino-methylene)-3-(2,2,5-trimethyl-4,6-dioxo-1,3-dioxan-5-yl)-succi-
nates. Mol. Diversity 2006, 10, 24.
16. Yavari, I.; Nasiri, F.; Djahaniani, H. Synthesis and dynamic NMR study of
ketenimines derived from tert-butyl isocyanide, alkyl 2-arylamino-2-oxo-acet-
ates, and dialkyl acetylenedicarboxylates. Mol. Diversity 2004, 8, 431.

Highly Functionalized Stable Ketenimines
551
17. Yavari, I.; Alizadeh, A.; Anary-Abbasinejad, M.; Bijanzadeh, H. R. Reaction
between alkyl isocyanides and dibenzoylacetylene in the presence of strong
NH-acids: Synthesis of highly functionalized aminofurans. Tetrahedron
2003, 59, 6083.
18. Shaabani, A.; Teimouri, M. B.; Arab-Ameri, S. A novel pseudo four-
component reaction: Unexpected formation of densely functionalized
pyrroles. Tetrahedron Lett. 2004, 45, 8409.
19. Anary-Abbasinejad, M.; Mosslemin, M. H.; Tahan, S.; Anaraki-Ardakani,
H. Synthesis of unsaturated amidines by three component reaction of alkyli-
socyanides, dialkyl acetylenedicarboxylates, and aromatic amides. J. Chem.
Res. 2006, 3, 170.
20. Anary-Abbasinejad, M.; Mosslemin, M. H.; Anaraki-Ardakani, H.; Tahan,
S. Synthesis of unsaturated amidine derivatives by three component reaction
of alkyl isocyanides, dialkyl acetylenedicarboxylates, and pyrrole or indole. J.
Chem. Res. 2006, 5, 306.
21. Anary-Abbasinejad, M.; Anaraky-Ardakani, H.; Rastegari, F.; Hassanabadi,
A. One-pot synthesis of functionalized keteneimins by three component reac-
tion of isocyanides, dialkyl acetylenedicarboxylates, and 4-phenylaminocou-
marin. J. Chem. Res. 2007, 10, 602.
22. Do¨mling, A. Recent developments in isocyanide based multicomponent reac-
tions in applied chemistry. Chem. Rev. 2006, 106, 17.
23. Walborsky, H. M.; Periasamy, M. P. In The Chemistry of Functional
Groups, Suppl. C; S. Patai, Z. Rappoport, (Eds.); Wiley: New York, 1983;
Chap. 20, 835.
24. Marcaccini, S.; Torroba, T. Use of isocyanides in heterocyclic synthesis. Org.
Prep. Proced. Int. 1993, 25, 141.