A convenient route to biologically important quinazolines using N-arylamino-1,3-diazabuta-1,3-dienes

Article abstract of DOI:10.1055/s-2005-918419

A potential and convenient protocol for the synthesis of 4-arylquinazolines and 4-aminoquinazolines by electrocyclisation of N-arylamino-1,3-diazabuta-1,3- dienes is described. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2005-918419

PAPER
3059
A Convenient Route to Biologically Important Quinazolines Using
N-Arylamino-1,3-diazabuta-1,3-dienes
C
V
onvenient Route
i
to
Q
uin
p
azolines
U
s
a
N
-Aryla
n
mino-1,3-diazabut
K
Department of Applied Chemistry, Guru Nanak Dev University, Amritsar 143005, Punjab, India
Fax +91(183)225881920; E-mail: mahajanmohinderp@yahoo.co.in
Received 11 April 2005; revised 12 May 2005
12
doyliminophosphoranes with aldehydes. The methodol-
ogy has been further improved and extended to the
condensation of N-arylbenzamidines with aldehydes.13
The quinazolines thus obtained were then tested for their
antibacterial activities against a panel of susceptible and
Abstract: A potential and convenient protocol for the synthesis of
-arylquinazolines and 4-aminoquinazolines by electrocyclisation
of N-arylamino-1,3-diazabuta-1,3-dienes is described.
4
Key words: quinazolines, electrocyclisation, N-arylamino-1,3-di-
azabuta-1,3-dienes, intramolecular H-bonding, amino-substituted
quinazolines
1
4
resistant Gram positive and Gram-negative organisms
and also as anxiolytic and GABAergic agents.15 The re-
ported efficient electrocyclisation of such dienes bearing
phenyl and H at C-4 prompted us to explore the synthesis
of some novel quinazolines through 1,3-diazabuta-1,3-
dienes substituted at C-4 by secondary amino and hydro-
gen/thio methyl groups (Figure 1).
Quinazoline derivatives have attracted a great deal of in-
terest, mainly concerning their synthesis, reactions and bi-
ological properties, as this structural motif appears in a
large number of pharmaceutical agents and natural prod-
1
,2
ucts. These compounds have shown remarkable activity
3
4
5
R
as antitubercular, antiviral and anticancer agents and
6
are also used as DNA ligands with affinity to benzodi-
azepines and adenosine receptors. Recently a great number
7
of fused pyrimidine derivatives became known as poten-
tial drug molecules against various types of proliferative
diseases, caused by over-expression of protein kinases.8
One of the most important compound families are
quinazolines; e.g. the best inhibitor of EGFR tyrosine ki-
N
N
SCH3/H
N
1
nase is PD153035 [6,7-dimethoxy-4-(3¢-bromophe-
N
TM
=
morpholine, pyrrolidine, piperidine, N,N-diethylamine
nyl)aminoquinazoline] and IRESSA
(gefitinib,
ZD1839), developed from this compound family, is cur-
rently the only approved and granted drug by the FDA for
the treatment of advanced non-small-cell lung cancer
Figure 1
(
NSCLC). The growing medicinal importance of these Surprisingly, such dienes failed to cyclise even under
heterocycles, especially N-arylaminoquinazolines, con- stringent thermal conditions for reasons still unaccounted
tinues to provide a strong rationale for the development of for. It was felt that 4-N-arylamino-substituted 1,3-diaza-
synthetic methods for their preparation. Taguchi et al. 1,3-dienes may be better contenders for the required elec-
have reported the synthesis of 4-arylamino-2-dialkylami- trocyclisation possibly because of intramolecular H-bond-
noquinazolines by reaction of dialkylcyanamides with 4- ing between N –H and N and the possible prototropic
1
5
9
substituted phenyl isothiocyanates. Recently Shi et al. shift between N and N . Also, the presence of intramolec-
1
5
have reported the preparation of 3-arylquinazolines by us- ular H-bonding in such systems should stabilize the s-
1
0
ing TiCl /Zn system. The reactions of N-imidoylimino- cisoid conformation in preference to s-trans form, which
4
phosphoranes with various aldehydes result in a variable is a prerequisite for the desired electrocyclisation. Thus in
ratio of quinazoline and dihydroquinazoline derivatives continuation of our interest in the azadiene chemistry,16
depending upon the nature of aldehydes as well as the em- we report herein the synthesis of novel quinazoline deriv-
1
1
ployed reaction conditions. The reaction apparently suf- atives 3 by the thermolysis of N-arylamino-1,3-diazabuta-
fers from disadvantages such as longer reaction periods 1,3-dienes 2 in refluxing toluene (6–8 h) (Scheme 1).
(
25–90 h), lower yields, lack of selectivity often leading to
The structures of the quinazolines 3 were elucidated on
the basis of spectral and analytical data. The detailed spec-
tral data are given in the experimental section and only the
salient features are discussed here. Thus quinazolines, 3b
for example, showed a molecular ion peak at m/z = 297.
a mixture of products and cumbersome workup proce-
dure. We recently utilized microwave technology in the
synthesis of quinazolines by the condensation of N-imi-
SYNTHESIS 2005, No. 18, pp 3059–3062
x
x.
x
x
.
2
0
0
5
–1
Its IR spectrum showed absorption peaks at 3460 cm and
Advanced online publication: 06.10.2005
DOI: 10.1055/s-2005-918419; Art ID: P05005SS
Georg Thieme Verlag Stuttgart · New York
–1
1
1
568 cm due to NH and C=N groups, respectively. Its H
©

3
060
V. Kumar et al.
PAPER
R
N
R
N
N
N
toluene reflux
–8 h
toluene reflux
6–8 h
N
R
N
6
R
N
R1
HN
N
SCH3
R1
HN
HN
R1
R1
5
2
3
4
R
H
R1
pyrrolidine
R
H
CH3
H
H
H
R1
H
a
b
c
d
e
f
a
b
c
d
e
f
CH3 pyrrolidine
morpholine
CH3 morpholine
piperidene
CH3 piperidene
H
H
CH3
OCH3
Cl
H
CH3
Cl
Scheme 2
Scheme 1
NMR spectrum exhibited the presence of N-arylamino
group, apart from other aromatic protons and the absence
of the thiomethyl group. The methodology has been fur-
lets at d = 2.03 and d = 3.73 due to four protons each of the
pyrrolidine group.
ther extended to the electrocyclisation of N-arylamino- Secondary amino substituted quinazoline constitute an
1
1
,3-diazabuta-1,3-dienes 4, where R is a secondary ami- important class of medicinal entities acting as a -receptor
1
no group. As expected, the reaction resulted in the synthe- antagonists and antihypertensive agents17 and the impor-
sis of amino-functionalised quinazolines 5 (Scheme 2). tant members include Prazosin and Doxazosin. A plausi-
The structures of these compounds were once again estab- ble mechanism leading to the formation of quinazolines 3
lished on the basis of spectral and analytical evidences. and 5 is depicted in (Scheme 3). As reported earlier, N-
The compound 5b for example showed a molecular ion aryl substituted 1,3-dienes exist in tautomeric forms I and
1
peak at m/z = 289. Its H NMR spectrum exhibited multip- II. In this mechanism, it is assumed that the electrocyclic
NH
N
H
N
N
N
N
R1
R1
II
I
N
N
Path-I
N
N
N
H
N
HN
HN
R1
HN 1H
R
R1
I
III
1
R = secondary amino
1
R = SCH3
N
N
N
N
HN
R1
3
5
Scheme 3
Synthesis 2005, No. 18, 3059–3062 © Thieme Stuttgart · New York

PAPER
Convenient Route to Quinazolines Using N-Arylamino-1,3-diazabuta-1,3-dienes
3061
–
1
ring closure of the stable tautomer form I leads initially to IR (KBr): 3450 (NH), 1595, 1554 (C=N) cm .
1
an intermediate III which undergoes aromatisation via the
H NMR (300 MHz): d = 2.38 (s, 3 H, CH ), 7.20–8.13 (m, 12 H,
3
1
expected elimination of methyl mercaptan (R = SCH ) ArH, NH), 8.75–8.79 (m, 2 H, ArH).
3
1
and aromatic amine (R = secondary amine) leading to the
13
C NMR (75 MHz): d = 21.2 (CH ), 113.7, 120.3, 121.4, 124.1,
3
desired quinazolines 3 and 5, respectively.
125.0, 128.1, 128.8, 129.0, 129.3, 130.4, 132.7, 138.2, 138.3, 150.7,
57.5, 160.1.
1
Thus a convenient protocol for the synthesis of 4-N-aryl
substituted and 4-secondary amino substituted quinazo-
lines has been developed. The reaction depends upon the
Anal. Calcd for C H N : C, 81.00; H, 5.50; N, 13.49. Found: C,
8
21 17
3
0.82; H, 5.42; N, 13.76.
substitution pattern of imino nitrogen, the conformational MS: m/z = 311 [M+].
preferences and only the N-arylamino-1,3-diazabuta-1,3-
4
-(p-Methoxyphenylamino)-2-phenylquinazoline (3d)
dienes underwent electrocyclisation to quinazoline deriv-
atives.
Yield: 85%; mp 250–252 °C.
–
1
IR (KBr): 3450 (NH), 1595, 1556 (C=N) cm .
1
H NMR (300 MHz): d = 3.85 (s, 3 H, OCH ), 3.96–6.99 (d, J = 8.0
3
Melting points were determined by the open capillary technique us-
ing Veego Precision Digital Melting Point apparatus (MP-D) and
are uncorrected. IR spectra were recorded on a Shimadzu D-8001
Hz, 2 H, ArH), 7.40–7.48 (m, 5 H, ArH, NH), 7.71–7.82 (m, 4 H,
ArH), 7.95–7.98 (d, J = 9.0 Hz, 1 H, ArH), 8.49–8.53 (m, 2 H, ArH).
1
13
13
spectrophotometer. H NMR and C NMR spectra were recorded
C NMR (75 MHz): d = 55.5 (OCH ), 113.7, 114.1, 120.3, 123.3,
3
in CDCl with Bruker AC-E 200 (200 MHz) and Jeol FT NMR AL-
125.9, 128.3, 128.5, 129.1, 130.2, 131.6, 132.7, 138.7, 150.9, 156.4,
157.5, 160.4.
3
3
00 (300 MHz) spectrometers using TMS as internal standard.
Chemical shift values are expressed in ppm and J values are given
in Hz. Splitting patterns are indicated as s: singlet, d: doublet, t: trip-
let, m: multiplet, q: quartet and br: broad peak. Mass spectra were
recorded on a Shimadzu GCMS-QP-2000 mass spectrometer. Ele-
mental analyses were performed on a Heraus CHN-O-Rapid Ele-
mental Analyzer. 1,3-Diazabuta-1,3-dienes were prepared
Anal. Calcd for C H N O: C, 77.04; H, 5.23; N, 12.84. Found: C,
2
1
17
3
7
7.16; H, 5.29; N, 12.66.
MS: m/z = 327 [M+].
4
-(p-Chlorophenylamino)-2-phenylquinazoline (3e)
1
8
Yield: 84%; mp 232–234 °C.
according to the reported procedure.
–
1
IR (KBr): 3501 (NH), 1593, 1563 (C=N) cm .
Cyclisation Reactions of 1,3-Diazabuta-1,3-dienes; General
Procedure
A solution of N-arylamino-1,3-diazabuta-1,3-diene (0.01 mol) in
anhyd toluene was refluxed for 6–8 h. The progress of the reaction
was monitored by TLC. On completion, the reaction mixture was
concentrated and triturated with hexane. The isolated product was
purified by recrystallisation with the hexane–EtOAc (10:1) mixture.
1
H NMR (300 MHz): d = 7.15–8.05 (m, 12 H, ArH, NH), 8.45–8.68
(
1
m, 2 H, ArH).
3
C NMR (75 MHz): d = 113.0, 120.7, 121.2, 124.0, 125.8, 128.1,
128.5, 128.8, 129.3, 130.1, 132.9, 138.0, 138.6, 150.3, 157.8, 160.2.
Anal. Calcd for C H N Cl: C, 72.40; H, 4.25; N, 12.66. Found: C,
7
2
0
14
3
2.20; H, 4.33; N, 12.78.
MS: m/z = 331.5 [M+].
2
-Phenyl-4-(N-phenylamino)quinazoline (3a)
Yield: 82%; mp 220–222 °C.
4
-(p-Chlorophenylamino)-6-methyl-2-phenylquinazoline (3f)
–
1
IR (KBr): 3460 (NH), 1595, 1568 (C=N) cm .
Yield: 80%; mp 261–263 °C.
IR (KBr): 3451 (NH), 1600, 1558 (C=N) cm–1.
1
H NMR (300 MHz): d = 7.12–7.17 (m, 1 H, ArH), 7.36–7.49 (m, 7
H ArH, NH), 7.66–7.90 (m, 5 H, ArH), 8.51–8.55 (m, 2 H, ArH).
1
H NMR (300 MHz): d = 2.50 (s, 3 H, CH ), 7.36–7.86 (m, 11 H,
3
1
3
C NMR (75 MHz): d = 113.7, 120.2, 121.2, 123.9, 125.9, 128.4,
ArH, NH), 8.46–8.49 (m, 2 H, ArH).
1
28.5, 128.9, 129.1, 130.2, 132.8, 138.5, 138.6, 150.9, 157.2, 160.3.
1
3
C NMR (75 MHz): d = 21.7 (CH ), 113.5, 119.2, 122.3, 128.3,
3
Anal. Calcd for C H N : C, 80.78; H, 5.08; N, 14.13. Found: C,
20
15
3
128.4, 128.7, 128.9, 130.1, 130.9, 136.3, 137.3, 138.5, 149.3, 156.6,
59.4.
8
0.62; H, 5.19; N, 14.19.
1
MS: m/z = 297 [M+].
Anal. Calcd for C H N Cl: C, 72.93; H, 4.66; N, 12.15. Found: C,
2
1
16
3
7
2.81; H, 4.54; N, 12.40.
6
-Methyl-2-phenyl-4-(N-phenylamino)quinazoline (3b)
MS: m/z = 345.5 [M+].
Yield: 81%; mp 218–219 °C.
–
1
IR (KBr): 3449 (NH), 1594, 1554 (C=N) cm .
2
-Phenyl-4-pyrrolidin-1-ylquinazoline (5a)
1
H NMR (300 MHz): d = 2.43 (s, 3 H, CH ), 7.25–8.20 (m, 12 H,
Yield: 82%; mp 150–151 °C.
3
ArH, NH), 8.65–8.69 (m, 2 H, ArH).
1
1
H NMR (200 MHz): d = 2.00–2.06 (m, 4 H, CH CH ), 3.72–3.78
2
2
3
C NMR (75 MHz): d = 20.8 (CH ), 113.3, 120.5, 121.0, 124.0,
(m, 4 H, CH NCH ), 7.50–7.58 (m, 7 H, ArH), 7.70–7.73 (m, 2 H,
2 2
3
1
1
25.4, 128.3, 128.5, 129.0, 129.1, 130.4, 132.9, 138.3, 138.7, 150.4,
57.0, 160.2.
ArH).
13
C NMR (50.4 MHz): d = 24.8 (CH CH ), 46.0 (CH NCH ), 117.6,
2
2
2
2
Anal. Calcd for C H N : C, 81.00; H, 5.50; N, 13.49. Found: C,
118.0, 120.2, 122.4, 125.6, 127.8, 135.8, 145.3, 158.0, 166.3.
21
17
3
8
0.88; H, 5.35; N, 13.77.
Anal. Calcd for C H N : C, 78.52; H, 6.22; N, 15.26. Found: C,
78.35; H, 6.36; N, 15.29.
1
8
17
3
MS: m/z = 311 [M+].
MS: m/z = 275 [M+].
4
-(p-Methylamino)-2-phenylquinazoline (3c)
Yield: 82%; mp 210–211 °C.
Synthesis 2005, No. 18, 3059–3062 © Thieme Stuttgart · New York

3
062
V. Kumar et al.
PAPER
6
-Methyl-2-phenyl-4-pyrrolidin-1-ylquinazoline (5b)
References
Yield: 78%; mp 140–141 °C.
(1) (a) Brown, D. J. Quinazoline: The Chemistry of Heterocyclic
Compounds, Vol 55; John Wiley and Sons: Chichester UK,
1
H NMR (200 MHz): d = 2.01–2.07 (m, 4 H, CH CH ), 2.37 (s, 3 H,
2
2
CH ), 3.70–3.76 (m, 4 H, CH NCH ), 7.50–7.58 (m, 6 H, ArH),
3
2
2
1996, Supplement I. (b) Jones, P.; Chambers, M.
7
.70–7.73 (m, 2 H, ArH).
Tetrahedron 2003, 58, 9973. (c) Webb, T. R.; Lvovskiy, D.;
Kim, S. A.; Ji, X.; Melman, M.; Lindeu, J.; Jacobson, K. A.
Bioorg. Med. Chem. 2003, 11, 77. (d) Michael, J. P. Nat.
Prod. Rep. 2002, 742. (e) Frère, S.; Thiéry, V.; Bailly, C.;
Besson, T. Tetrahedron 2003, 59, 773.
1
3
C NMR (50.4 MHz): d = 21.1 (CH ), 24.9 (CH CH ), 45.7
3
2
2
(
CH NCH ), 117.3, 118.2, 120.1, 122.5, 123.3, 125.4, 127.7, 130.2,
2 2
1
35.6, 145.1, 157.9, 166.6.
Anal. Calcd for C H N : C, 78.86; H, 6.62; N, 14.52. Found: C,
7
MS: m/z = 289 [M+].
19
19
3
(
2) (a) Billimmoria, A. D.; Cava, M. P. J. Org. Chem. 1994, 59,
9.08; H, 6.60; N, 14.32.
6772. (b) Blackman, A.; Hambley, T. M.; Picker, R.; Taylor,
W. C.; Thirasana, N. Tetrahedron Lett. 1987, 28, 5561.
3) Kunes, J.; Bazant, J.; Pour, M.; Waisser, K.; Slosarek, M.;
Janota, J. Farmaco 2000, 55, 725.
(
(
(
(
4
-Morpholin-4-yl-2-phenylquinazoline (5c)
Yield: 68%; mp 157–158 °C.
4) El-Sherbeny, M. A.; Gineinah, M. M.; Nasr, M. N.; El-
1
Shafeih, F. S. Arzneim.-Forsch. 2003, 53, 206.
H NMR (200 MHz): d = 3.83–3.89 (m, 4 H, CH NCH ), 3.96–4.01
m, 4 H, CH OCH ), 7.54–7.62 (m, 7 H, ArH), 7.74–7.76 (m, 2 H,
2
2
5) Khalil, A. A.; Abdel-Hamid, S. G.; Al-Obaid, A. M.; El-
Subbag, H. I. Arch. Pharm. (Weinheim, Ger.) 2003, 336, 95.
6) Malecki, N.; Caroto, P.; Rigo, B.; Goossens, J. F.; Houssin,
R.; Bailly, C.; Henichart, J. P. Bioorg. Med. Chem. 2004, 12,
(
2 2
ArH).
1
3
C NMR (50.4 MHz): d = 44.5 (CH NCH ), 66.8 (CH OCH ),
2
2
2
2
1
17.9, 126.3, 128.5, 129.5, 130.2, 131.8, 135.6, 137.5, 160.7, 168.5.
641.
Anal. Calcd for C H N O: C, 74.20; H, 5.88; N, 14.42. Found: C,
(7) Bertelli, L.; Biagi, G.; Giorgi, I.; Livi, O.; Manera, C.;
Scartoni, V.; Lucacchini, A.; Giannaccini, G.; Barili, P. L.
Eur. J. Med. Chem. 2000, 35, 333.
18
17
3
7
4.28; H, 5.64; N, 14.2.
MS: m/z = 291 [M+].
(8) (a) Orfi, L.; Waczek, F.; Pato, J.; Varga, I.; Hegymegi-
Barakonyi, B.; Houghten, R. A.; Keri, G. Curr. Med. Chem.
6
-Methyl-2-phenyl-4-morpholino-4-ylquinazoline (5d)
2
004, 11, 2549. (b) Fry, D. W.; Kraker, A. J.; McMichael,
Yield: 71%; mp 147–148 °C.
A.; Ambroso, L. A.; Nelson, J. M.; Leopold, W. R.; Connors,
1
H NMR (200 MHz): d = 2.41 (s, 3 H, CH ), 3.81–3.86 (m, 4 H,
3
R. W.; Bridges, A. J. Science 1994, 265, 1093.
CH NCH ), 3.98–4.02 (m, 4 H, CH OCH ), 7.54–7.62 (m, 6 H,
2
2
2
2
(9) Oishi, A.; Yasumoto, M.; Goto, M.; Tsuchiya, T.; Shibuya,
I.; Taguchi, Y. Heterocycles 1994, 38, 2073.
(10) Shi, D.; Wang, J.; Shi, C.; Rong, L.; Zhuang, Q.; Hu, H.
Synlett 2004, 1098.
ArH), 7.74–7.76 (m, 2 H, ArH).
1
3
C NMR (50.4 MHz): d = 21.37 (CH ), 44.56 (CH NCH ), 66.97
3
2
2
(
CH OCH ), 117.7, 126.0, 128.3, 128.5, 129.5, 129.7, 130.0, 131.3,
2 2
(
11) (a) Rossi, E.; Stradi, R.; Visentin, P. Tetrahedron 1990, 46,
1
35.7, 137.9, 160.9, 168.7.
3581. (b) Rossi, E.; Stradi, R.; Clenantano, G.; Strada, A.
Anal. Calcd for C H N O: C, 74.73; H, 6.27; N, 13.76. Found: C,
7
MS: m/z = 305 [M+].
19
19
3
Tetrahedron Lett. 1990, 31, 903.
12) Kumar, V.; Sharma, A. K.; Mahajan, M. P. Synth. Commun.
2004, 34, 49.
13) Kumar, V.; Mohan, C.; Gupta, M.; Mahajan, M. P.
Tetrahedron 2004, 61, 3533.
4.92; H, 6.40; N, 13.44.
(
(
2
-Phenyl-4-piperidin-1-ylquinazoline (5e)
Yield: 77%; mp 131–132 °C.
(14) Bedi, P. M.; Kumar, V.; Mahajan, M. P. Bioorg. Med. Chem.
1
Lett. 2004, 14, 5211.
15) Goel, R. K.; Kumar, V.; Mahajan, M. P. Bioorg. Med. Chem.
Lett., in press.
16) (a) Jayakumar, S.; Ishar, M. P. S.; Mahajan, M. P.
Tetrahedron 2002, 58, 379. (b) Mazumdar, S. N.; Ibnusaud,
I.; Mahajan, M. P. Tetrahedron Lett. 1987, 28, 2641.
H NMR (200 MHz): d = 1.70–1.75 (m, 6 H, CH CH CH ), 3.99–
2
2
2
(
4
2
.04 (m, 4 H, CH NCH ), 7.50–7.58 (m, 7 H, ArH), 7.70–7.74 (m,
2 2
H, ArH).
(
1
3
C NMR (50.4 MHz): d = 25.1 (CH ), 26.3 (CH CH ), 44.2
2 2
2
2
2
(
1
CH NCH ), 117.5, 118.6, 120.8, 122.5, 125.1,130.5, 135.4, 145.5,
57.6, 166.3.
(c) Mazumdar, S. N.; Mahajan, M. P. Tetrahedron 1991, 47,
Anal. Calcd for C H N : C, 78.86; H, 6.62; N, 14.52. Found: C,
1473. (d) Mazumdar, S. N.; Mukherjee, S.; Sharma, A. K.;
Sengupta, D.; Mahajan, M. P. Tetrahedron 1994, 50, 7579.
19
19
3
7
8.79; H, 6.83; N, 14.38.
(e) Mukherjee, S.; Mazumdar, S. N.; Sharma, A. K.;
MS: m/z = 289 [M+].
Mahajan, M. P. Heterocycles 1998, 47, 933. (f) Dey, P. D.;
Sharma, A. K.; Bharatam, P. V.; Mahajan, M. P.
Tetrahedron 1997, 53, 13829.
6
-Methyl-2-phenyl-4-piperidin-1-ylquinazoline (4f)
Yield: 81%; mp 137–138 °C.
(
17) Dey, S.; Ramachandra, M.; Pastan, I.; Gottesman, M. M.;
Ambudkar, S. V. Proc. Natl. Acad. Sci. U.S.A. 1997, 94,
10594.
(18) (a) Sharma, A. K.; Mahajan, M. P. Tetrahedron Lett. 1986,
27, 5875. (b) Mazumdar, S. N.; Mahajan, M. P. Synthesis
1
H NMR (200 MHz): d = 1.72–1.77 (m, 6 H, CH CH CH ), 2.38 (s,
2
2
2
3
7
H, CH ), 3.97–4.02 (m, 4 H, CH NCH ), 7.50–7.58 (m, 6 H, ArH),
3
2
2
.70–7.74 (m, 2 H, ArH).
1
3
C NMR (50.4 MHz): d = 19.3 (CH ), 25.2 (CH ), 26.0 (CH CH ),
3
2
2
2
1
990, 417. (c) Dey, P. D.; Sharma, A. K.; Bhartam, P. V.;
4
1
4.4 (CH NCH ), 117.0, 118.3, 120.4, 122.7, 123.4, 125.2, 127.9,
30.0, 135.3, 145.3, 157.7, 166.3.
2 2
Mahajan, M. P. Tetrahedron 1997, 53, 13829. (d) Dey, P.
D.; Sharma, A. K.; Rai, S. N.; Mahajan, M. P. Tetrahedron
1995, 51, 7459.
Anal. Calcd for C H N : C, 79.17; H, 6.98; N, 13.85. Found: C,
20
21
3
7
9.32; H, 6.80; N, 13.88.
MS: m/z = 303 [M+].
Synthesis 2005, No. 18, 3059–3062 © Thieme Stuttgart · New York