New aromatic annulation reaction via a C14 enaminone synthon: Synthesis of 'terpenoid-like chalcones'

Article abstract of DOI:10.1016/j.tetlet.2005.07.141

Diverse functionalized synthons from a new enaminone are reported. These synthons were easily obtained in a one pot process starting from a compound derived from β-ionone. A new annulation reaction of this C-14 compound with several anions led to new 'terpenoid-like' chalcones.

Full text of DOI:10.1016/j.tetlet.2005.07.141

Tetrahedron
Letters
Tetrahedron Letters 46 (2005) 6671–6674
New aromatic annulation reaction via a C14 enaminone
synthon: synthesis of Ôterpenoid-like chalconesÕ
a
a
a
Alain Valla,a, Benoist Valla, Dominique Cartier, Regis Le Guillou,
*
´
Roger Labiaa and Pierre Potierb
aLaboratoire de Chimie et Biologie des Substances Naturelles, FRE 2125 CNRS 6, rue de l’Universite´, 29000 Quimper, France
bInstitut de Chimie des Substances Naturelles, avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
Received 8 May 2005; revised 18 July 2005; accepted 28 July 2005
Available online 15 August 2005
Abstract—Diverse functionalized synthons from a new enaminone are reported. These synthons were easily obtained in a one pot
process starting from a compound derived from b-ionone. A new annulation reaction of this C-14 compound with several anions led
to new Ôterpenoid-likeÕ chalcones.
Ó 2005 Elsevier Ltd. All rights reserved.
Licochalcone A (Fig. 1), a natural antimalarial agent1
isolated from Glycyrrhiza inflata. Consequently, many
synthetic derivatives have also been recently recognized
as potential antimalarials.
and NADH-cytochrome C reductases2 but also of pro-
tease activities of Plasmodium and Trypanosomes.3
On the other hand, enaminones are versatile ambident
synthetic intermediates, which combine the nucleophilic-
ity of enamines and the electrophilicity of enones
(Fig. 2).
This natural compound has been identified as a potent
inhibitor of mitochondrial functions in Leishmania, such
as fumarate reductase (FRD), succinate dehydrogenase
(SDH), NADH dehydrogenase (NDH), and succinate
Enaminones have been frequently used in organic chem-
istry4 and recently, Stanovnik and Svete reported two
exhaustive reviews on the syntheses of these derivatives
and their use as synthetic intermediates in heterocyclic
chemistry and natural products synthesis.5
O
Taking into account the biological properties of Lico-
chalcone A, we have used the versatility of these com-
pounds to synthesize, from a new retinoid enaminone
HO
MeO
OH
Figure 1. Licochalcone A.
E+
E+
O
O
O
:
:
:
N
R
N
R
N
R
E+
O
Nu-
O
:
:
N
R
N
R
Nu-
Figure 2.
Keywords: Annulation; Enaminones; Salicylates; Terpenoid-like chalcones.
*
Corresponding author. Tel.: +33 06 61 55 43 36; fax: +33 02 98 64 19 48; e-mail: alain.valla@cegetel.net
0040-4039/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2005.07.141

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A. Valla et al. / Tetrahedron Letters 46 (2005) 6671–6674
derived from ethyl acetoacetate (a: NaH, DME,
MeO OMe
O
O
ꢀ15 °C, then ethyl acetoacetate in DME, b: ꢀ40 °C,
nBuLi in hexanes, 20 min, then 1 in DME, and reflux,
30 min) led to formation of derivatives 2a–c (60–80%)
and 3 (70%), respectively, in good yield (Fig. 4).
H
N
N
1
Figure 3.
Compound 1 could also be transformed into several new
functionalized synthons, such as sulfoxide 4 (ꢀ20 °C,
nBuLi in hexanes, MeC6H4SOMe in DME, 0 °C,
20 min, then 1 in DME and reflux, 30 min, 55%), sulf-
ones 5 (ꢀ20 °C, nBuLi in hexanes, dimethylsulfone, then
1 in DME and reflux, 30 min, 55%), 6 (ꢀ20 °C, nBuLi in
hexanes, MeC6H4SO2Me in DME, 0 °C, 20 min, 1 in
DME then reflux, 30 min, 75%), and ketone 7 (NaH,
DME, ꢀ15 °C, acetone, then 1 in DME and reflux,
30 min, 90%) . . . thereby allowing extension of the ethyl-
enic linkage (Fig. 5).
1 (derived from b-ionone), a series of terpenoid analogs
of this natural chalcone, as potential antimalarial agents
(Fig. 3).
Similarly to previous reports,6 condensations of 1 with
alkyllithium (MeLi, nBuLi, or tBuLi in hexanes,
ꢀ20 °C, then 1 in DME and reflux, 30 min), Grignard
reagents (for compound 2a: MeMgBr in ether, ꢀ20 °C,
then 1 in DME and reflux, 30 min) or with the dianion
O
O
MeCOCH2COOEt
RLi or
N
OH
COOEt
R
RMgX, 60-80%
1: NaH; 2: nBuLi, 70%
2
1
3
Figure 4. Compound 2a: R = Me; 2b: R = nBu; 2c: R = tBu.
O
O
SO2Me
SOMe
MeSO2Me
N
MeSOMe
5
4
O
O
O
O
O
O
SO2C6H4Me
4-MeC6H4SO2Me
MeCOMe
7
6
Figure 5.
_
O
O
_
OMe
N
O
OH
8
9
N
1
N
_
_
COOEt
COOMe
O
OH
1
OH
7
15
10
6
2
14
9
8
5
3
11
13
N
12
11
4
10
Figure 6. Compound 8: ꢀ10 °C, nBuLi in hexanes, N-(3-methylbut-2-enylidene) propan-2-amine in DME, then 1 in DME and reflux, 30 min, 40%; 9:
ꢀ30 °C, LDA in hexanes, 4-methoxybut-3-en-2-one in DME then 1 in DME and reflux, 30 min, 50%; 10: ꢀ50 °C, LDA in hexanes, 3,3-
dimethylacrylate in DME, ꢀ20 °C then 1 in DME and reflux, 30 min, 70%; 11: ꢀ50 °C, LDA in hexanes, methyl-3-(pyrrolidin-1-yl) but-2-enoate in
DME, ꢀ20 °C then 1 in DME and reflux, 30 min, 35%.

A. Valla et al. / Tetrahedron Letters 46 (2005) 6671–6674
6673
O-
-
O
N
O
O
N
O
OMe
N
O
MeO
-Me2NH
O
O
O
O
O
HO
10
Figure 7.
5. Stanovnik, B.; Svete, J. Synlett 2000, 1077–1091; Stanov-
nik, B.; Svete, J. Chem. Rev. 2004, 104, 2433–2480.
Surprisingly, some anions afforded new substituted a,b-
unsaturated ketones 8–11, which may be considered as
Ôterpenoid analogsÕ of chalcones7 (Fig. 6).
6. Murphy, W. S.; Bertrand, M. J. J. Chem. Soc., Perkin
Trans. 1 1998, 4115–4120; Kirschbaum, S.; Waldmann, H.
J. Org. Chem. 1998, 63, 4936–4946; Trautwein, A. W.;
Jung, G. Tetrahedron Lett. 1998, 39, 8263–8266; Nishi-
mura, N.; Koyano, Y.; Sugiura, M.; Maeba, I. Heterocycles
1999, 51, 803–809; Cuvigny, T.; Normand, H. Bull. Soc.
Chim. Fr. 1960, 515–521; Abdulla, R. F.; Fuhr, K. H. J.
Org. Chem. 1978, 43, 4248–4250; Takeuchi, N.; Handa, S.;
Koyama, K.; Kamata, K.; Goto, K.; Tobinaga, S. Chem.
Pharm. Bull. 1991, 39, 1655–1658.
7. Synthesis of compound 1. A solution of 21 mL (0.1 mol) of
b-ionone and 23 mL of N,N-dimethylformamide dimethyl-
acetal (DMFDMA) (1.5 equiv) was heated at 80 °C for 6 h
(Dean–Stark) and then refluxed for 12 h. The excess of
DMFDMA was distilled under reduced pressure and the
enaminone 1 was crystallized in a mixture of pentane/ether:
The formation of these compounds may be explained by
the mechanism, depicted in Figure 7 for the formation
of compound 10. The reaction resembles a Robinson
annulation. After conjugate addition of the enolate,
the new enolate (in brackets) can, in an intramolecular
aldol reaction, cyclize into a cyclohexanone. The latter,
after elimination of dimethylamine, furnishes a cyclo-
hexadienone, which aromatizes into a phenol.
To our knowledge, this represents the first example of
this kind of annulation–aromatization.
2/1. Yellow crystals mp: 70 °C (95%) IR mCO: 1653 cmꢀ1
.
1H NMR (d: ppm; J: Hz, CDCl3): 7.70 (d, 1H, J = 12.5,
H11); 7.19 (d, 1H, J = 16, H7); 6.15 (d, 1H, J = 16, H8); 5.18
(d, 1H, J = 12.5, H10); 3.10 and 2.90 (2s, 6H, N(CH3)2);
2.04 (m, 2H, 4-CH2); 1.77 (s, 3H, 5-CH3); 1.61 (m, 2H, 3-
CH2); 1.47 (m, 2H, 2-CH2); 1.07 (s, 6H, 1-CH3). 13C NMR
(CO): 186.8 (CH); 152.9; 138.1; 132.2; 96.2 (CH2): 39.6;
33.2; 19.0 (CH3): 28.8; 21.6. Anal. Calcd for C16H25NO: C,
77.68; H, 10.19; N, 5.66; O, 6.47. Found: C, 77.49; H, 10.35;
N, 5.68; O, 6.48.
Acknowledgement
We are indebted to Dr. R. H. Dodd for helpful
discussions.
References and notes
General procedure for the synthesis of compounds 2. Under
argon were slowly added at ꢀ20 °C 15 mmol of alkyl
lithium in hexanes (or methylmagnesium bromide in ether
for compound 2a) in 10 mL of anhydrous DME to 15 mmol
of enaminone in 10 mL of anhydrous DME. The mixture
was warmed to rt and then heated at reflux for 1 h. The
crude mixture was cooled to 0 °C and hydrolyzed by a cold
solution of N HCl. After addition of 50 mL of ether, the
organic layer was washed with brine and dried over
MgSO4. The crude product was purified by column
chromatography (SiO2/CH2Cl2).
1. Chen, M.; Theander, T. G.; Christensen, S. B.; Hviid, L.;
Zhai, L.; Kharazmi, A. Antimicrob. Agents Chemother.
1994, 38, 1470–1475.
2. Zhai, L.; Chen, M.; Blom, J.; Theander, T. G.; Christensen,
S. B.; Kharazmi, A. J. Antimicrob. Agents Chemother. 1999,
43, 793–803; Chen, M.; Zhai, L.; Christensen, S. B.;
Theander, T. G.; Kharazmi, A. Antimicrob. Agents Chemo-
ther. 2001, 45, 2023–2029.
3. Dominguez, J. N.; Charris, J. E.; Lobo, G.; Gamboa de
Dominguez, N.; Moreno, M. M.; Riggione, F.; Sanchez, E.;
Olson, J.; Rosenthal, P. J. Eur. J. Med. Chem. 2001, 36,
555–560; Xu, H.; Wan, M.; Dong, H.; But, P. P.; Foo, L. Y.
Biol. Pharm. Bull. 2000, 23, 1072–1076.
4. Abdulla, R. F.; Brinkmeyer, R. S. Tetrahedron 1979, 35,
1675–1735; Michael, J. P.; de Koning, C. B.; Gravestock,
D.; Hosken, G. D.; Howard, A. S.; Jungmann, C. M.;
Krause, R. W. M.; Parsons, A. S.; Pelly, S. C.; Stanbury, T.
V. Pure Appl. Chem. 1999, 71, 979–988; Katritzky, A. R.;
Barcock, R. A.; Long, Q.-H.; Balasubramanian, M.;
Malhotra, N.; Greenhill, J. V. Synthesis 1993, 233–236;
Bartoli, G.; Cimarelli, C.; Palmieri, G.; Bosco, M.;
Dalpozzo, R. Synthesis 1990, 895–897.
Compound 2a: Yellow oil (65%). IR mCO: 1679; 1662 cmꢀ1
.
1H NMR (d: ppm; J: Hz, CDCl3): 7.45 (d, 1H, J = 16.0,
H7); 6.95 (m, 1H, H11); 6.40 (2d, 2H, J = 16.0, H8+H10);
2.18 (m, 2H, CH2); 2.00 (d, 3H, J = 3.0, 12-CH3); 1.83 (s,
3H, 5-CH3); 1.68 (m, 2H, 3-CH2); 1.52 (m, 2H, 2-CH2); 1.10
(s, 6H, 1-CH3). 13C NMR (CO): 189.3 (CH): 143.2; 143.0;
131.3; 129.4; 110.0 (CH2): 40.2; 34.0; 19.3 (CH3): 29.2; 22.2;
18.9. Anal. Calcd for C15H22O: C, 82.52; H, 10.16; O, 7.33.
Found: C, 82.29; H, 10.35; O, 7.36.
Compound 2b: Yellow oil (85%). IR mCO: 1679; 1662 cmꢀ1
1H NMR (d: ppm; J: Hz, CDCl3): 7.39 (d, 1H, J = 16.0,
.

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A. Valla et al. / Tetrahedron Letters 46 (2005) 6671–6674
H7); 6.91 (m, 1H, H11); 6.35 (2d, 2H, J = 16.0, H8+H10);
2H, 3-CH2); 1.44 (m, 2H, 2-CH2); 1.05 (s, 6H, 1-CH3).13C
NMR (CDCl3) (CO): 187.7 (CH): 145.1; 136.8; 130.8; 128.6
(CH2): 58.3; 40.4; 34.2; 19.2 (CH3): 40.5; 29.2; 22.3. Anal.
Calcd for C16H24O3S: C, 64.83; H, 8.16; O, 16.19; S, 10.82.
Found: C, 64.59; H, 8.31; O, 16.27. S, 10.83.
2.25 (m, 2H, 12-CH2); 2.05 (m, 2H, 4-CH2); 1.78 (s, 3H, 5-
CH3); 1.62 (m, 2H, 3-CH2); 1.47 (m, 4H, 2-CH2+13-CH2);
1.38 (m, 2H, 14-CH2); 1.07 (s, 6H, 1-CH3); 0.91 (t, J = 7.2,
15-CH3). 13C NMR (CO): 189.4 (CH): 147.4; 142.6; 129.2;
96.2 (CH2): 39.6; 33.5; 33.2; 19.0 (CH3): 28.8; 21.6. Anal.
Calcd for C18H28O: C, 83.02; H, 10.84; O, 6.14. Found: C,
82.89; H, 11.05; O, 6.06.
Compound 6: Beige crystals, mp 85 °C (pentane). IR mCO
:
1661 cmꢀ1. H NMR (d: ppm; J: Hz, CDCl3): 7.77 (d, 2H,
J = 8.3, Ar); 7.39 (d, 1H, J = 16.1, H7); 7.36 (d, 2H,
J = 8.3, Ar); 6.65 (m, 1H, H11); 6.38 and 6.30 (2d, J = 15.7
and 16.1, H8+H10); 3.97 (d, 2H, J = 7.6, H12); 2.45 (s, 3H,
C6H5–CH3); 2.09 (m, 2H, 4-CH2); 1.79 (s, 3H, 5-CH3); 1.62
(m, 2H, 3-CH2); 1.49 (m, 2H, 2-CH2); 1.08 (s, 6H, 6-CH3).
13C NMR (CDCl3) (CO): 187.8 (CH): 144.8; 136.7; 130.8;
130.4; 128.8; 128.7; 127.8 (CH2): 60.0; 40.2; 34.2; 19.2
(CH3): 45.0; 29.2; 22.1. Anal. Calcd for C22H28O3S: C,
70.93; H, 7.58; O, 12.88; S, 8.61. Found: C, 70.68; H, 7.71;
O, 12.94. S, 8.67.
1
Compound 2c: Yellow oil (70%). IR mCO: 1661 cmꢀ1 1H
.
NMR (d: ppm; J: Hz, CDCl3): 7.40 (d, 1H, J = 16.0, H7);
6.92 (d, 1H, J = 15.9, H11); 6.38 (d, 1H, J = 16.0, H8); 6.26
(d, 1H, J = 15.9, H10); 2.09 (m, 2H, 4-CH2); 1.80 (s, 3H, 5-
CH3); 1.64 (m, 2H, 3-CH2); 1.49 (m, 2H, 2-CH2); 1.12 (s,
9H, 12-CH3); 1.09 (s, 6H, 1-CH3). 13C NMR (CO): 189
(CH): 157.6; 143.2; 129.6; 124.9 (CH2): 40.1; 34.0; 19.3
(CH3): 29.2; 29.1; 22.2. Anal. Calcd for C16H22O: C, 82.52;
H, 10.16; O, 7.33. Found: C, 82.26; H, 10.29; O, 7.45.
Compound 3: Under argon were slowly added at ꢀ10 °C
15 mmol of ethyl acetoacetate in 10 mL of anhydrous DME
to a suspension of 15 mmol of NaH (60% dispersion in
mineral oil) in 10 mL of anhydrous DME. After 15 min at
ꢀ10 °C, 15 mmol of nBuLi (1.6 M in hexanes) were added
at ꢀ20 °C and, after 15 min at ꢀ20 °C, 15 mmol of 1 in
10 mL of anhydrous DME were rapidly added and the
mixture was warmed to rt and then heated at reflux for 1 h.
The crude mixture was cooled to 0 °C and hydrolyzed by a
cold solution of N HCl. After addition of 50 mL of ether,
the organic layer was washed with brine and dried over
MgSO4. The crude product was purified by column
chromatography (SiO2/CH2Cl2).
Compound 7: Two isomers. Yellow oil (80%). IR mCO
:
1661 cmꢀ1. 1H NMR (d: ppm; J: Hz, CDCl3): 7.44–7.37 (m,
1H, H7); 7.05–6.91 (m, 1H, H11); 6.42–6.36 (m, 1H, H8);
6.19–6.12 (m, 1H, H12); 3.53 (dd, 2H, J = 7.0, J = 1.5, 10-
CH2 maj.); 3.38 (dd, 2H, J = 6.9, J = 1.25, 10-CH2 min.);
2.29 (s, 3H, 13-CH3 maj.); 2.22 (s, 3H, 13-CH3 min.); 2.08
(m, 2H, 4-CH2); 1.76 (s, 3H, 5-CH3); 1.60 (m, 2H, 3-CH2);
1.49 (m, 2H, 2-CH2); 1.07 (s, 6H, 1-CH3). Anal. Calcd for
C17H24O2: C, 78.42; H, 9.29; O, 12.29. Found: C, 78.28; H,
9.46; O, 12.26.
Compound 8: Yellow oil (50%). IR mCO: 1661 cmꢀ1 1H
.
NMR (d: ppm; J: Hz, CDCl3): 7.88 and 7.26 (2d, 4H,
J = 8.0, Ar); 7.58 (d, 1H, J = 15.8, H7); 6.95 (d, 1H,
J = 15.8, H8); 2.40 (s, 3H Ar-CH3); 2.09 (m, 2H, 4-CH2);
1.85 (s, 3H, 5-CH3); 1.64 (m, 2H, 3-CH2); 1.50 (m, 2H, 2-
CH2); 1.13 (s, 6H, 1-CH3). 13C NMR (CO): 190.0 (CH):
144.5; 129.6; 129.0; 126.5 (CH2) 40.2; 34.1; 19.3 (CH2):
29.3; 22.3; 22.0. Anal. Calcd for C19H24O: C, 85.03; H, 9.01;
O, 5.96. Found: C, 84.80; H, 9.21; O, 5.99.
Yellow oil (70%). IR mCO: 1661 cmꢀ1. 1H NMR (d: ppm; J:
Hz, CDCl3): 7.38 (dd, 1H, J = J0 = 8.2, H11); 7.04 (d, 1H,
J = 8.2, H12); 6.94 (d, 1H, J = 16.0, H7); 6.92 (dd, 1H,
J = 16.0 and 1, H10); 6.43 (dd, 1H, J = 16 and 1, H8); 4.46
(q, 2H, J = 7.1, 14-COOCH2); 2.06 (m, 2H, 4-CH2); 1.79 (s,
3H, 5-CH3); 1.65 (m, 2H, 3-CH2); 1.51 (m, 2H, 2-CH2); 1.39
(t, 3H, J = 7.1, 14-COOCH2CH3); 1.09 (s, 6H, 1-CH3). 13
C
Compound 9: Yellow oil (50%). IR mCO: 1644 cmꢀ1 1H
.
NMR (CO): 171; 162.1 (CH): 134.0; 133.5; 130.0; 119.6;
116.2 (CH2): 61.7; 39.4; 32.7; 19.2 (CH3): 28.8; 21.4; 14.3.
Anal. Calcd for C20H26O3: C, 76.40; H, 8.33; O, 15.27.
Found: C, 76.11; H, 8.45; O, 15.44.
NMR (d: ppm; J: Hz, CDCl3): 8.35 (s, 1H, OH); 7.94 (d,
2H, J = 8.5, H11+H15); 7.62 (d, 1H, J = 15.8, H7); 6.98 (d,
1H, J = 15.8, H8); 6.99 (d, 2H, J = 8.5, H12+H14); 2.12 (m,
2H, 4-CH2); 1.86 (s, 3H, 5-CH3); 1.64 (m, 2H, 3-CH2); 1.50
(m, 2H, 2-CH2); 1.13 (s, 6H, 1-CH3). 13C NMR (CO):
190.1; 163.6 (CH): 144.9; 131.7; 130.0; 126.0; 116.1; 115.8
(CH2): 40.3; 34.2; 19.3 (CH3): 29.3; 22.3. Anal. Calcd for
C18H22O2: C, 79.96; H, 8.20; O, 11.84. Found: C, 79.71; H,
8.43; O, 11.86.
General procedure for the synthesis of compounds 4–11.
Under argon were slowly added 15 mmol of the reagent in
10 mL of anhydrous DME to 20 mmol of base in 10 mL of
anhydrous DME (the temperature and the base used are
reported in Fig. 6). After addition of 15 mmol of 1 in 10 mL
of anhydrous DME, the mixture was warmed to rt and then
heated at reflux for 30 min. The crude mixture was cooled
to 0 °C and hydrolyzed by a cold solution of N HCl. After
addition of 50 mL of ether, the organic layer was washed
with brine and dried over MgSO4. The crude product was
purified by column chromatography (SiO2/CH2Cl2).
Compound 10: Yellow crystals mp: 90 °C (70%). IR mCO
:
1638 cmꢀ1. H NMR (d: ppm; J: Hz, CDCl3): 7.71 (d, 1H,
J = 15.6, H7); 7.70 (d, 1H, J = 8.2, H15); 7.06 (d, 1H,
J = 15.6, H8); 6.83 (s, 1H, H12); 6.73 (d, 1H, J = 8.2, H14);
2.37 (s, 3H 13-CH3); 2.14 (m, 2H, 4-CH2); 1.89 (s, 3H, 5-
CH3); 1.67 (m, 2H, 3-CH2); 1.53 (m, 2H, 2-CH2); 1.16 (s,
6H, 1-CH3). 13C NMR (CO): 193.3; 163.6 (CH): 145.1;
129.9; 124.4; 120.5; 119.0 (CH2): 40.3; 34.3; 19.3 (CH3):
53.3; 29.3; 22.4. Anal. Calcd for C19H24O2: C, 80.24; H,
8.51; O, 11.25. Found: C, 80.00; H, 8.78; O, 11.22.
1
Compound 4: Yellow oil (50%). IR mCO: 1659 cmꢀ1 1H
.
NMR (d: ppm; J: Hz, CDCl3): 7.47 (d, 1H, J = 16.0, H7);
6.86 (m, 1H, H11); 6.64 (d, 1H, J = 16.0, H8); 6.36 (d, 1H,
J = 16.0, H10); 3.63 (m, 2H, H12); 2.59 (s, 3H, 14-CH3); 2.07
(m, 2H, 4-CH2); 1.79 (s, 3H, 5-CH3); 1.61 (m, 2H, 3-CH2);
1.47 (m, 2H, 2-CH2); 1.08 (s, 6H, 6-CH3). 13C NMR
(CDCl3) (CO): 187.7 (CH): 144.7; 136.1; 132.2; 129.0
(CH2): 56.8; 40.2; 34.2; 19.2 (CH3): 38.2; 29.2; 22.3. Anal.
Calcd for C16H24O2S: C, 68.53; H, 8.63; O, 11.41; S, 11.43.
Found: C, 68.28; H, 8.81; O, 11.54. S, 11.37.
Compound 11: Beige crystals mp: 125 °C (65%). IR mCO
:
1638 cmꢀ1. H NMR (d: ppm; J: Hz, CDCl3): 7.63 (d, 1H,
J = 9.1, H12); 7.58 (d, 1H, J = 15.6, H7); 6.98 (d, 1H,
J = 15.6, H8); 6.13 (dd, 1H, J = 9.1, J = 2.4, H12); 6.03 (d,
1H, J = 2.4, H14); 3.39 (m, 4H, CH2–N); 2.12 (m, 2H, 4-
CH2); 2.05 (m, 4H, CH2–CH2–N); 1.86 (s, 3H 5-CH3); 1.67
(m, 2H, 3-CH2); 1.50 (m, 2H, 2-CH2); 1.14 (s, 6H, 1-CH3).
13C NMR (CO): 190.3 (CH): 142.1; 132.3; 124.8; 104.3;
109.0 (CH2): 47.6;39.8; 33.7; 25.3; 19.0 (CH3): 29.0; 21.9.
Anal. Calcd for C22H29NO2: C, 77.84; H, 8.61; N, 4.13; O,
9.43. Found: C, 77.62; H, 8.83; N, 4.17; O, 9.38.
1
Compound 5: Yellow oil (50%). IR mCO: 1662 cmꢀ1 1H
.
NMR (d: ppm; J: Hz, CDCl3): 7.45 (d, 1H, J = 16.0, H7);
6.81 (m, 1H, H11); 6.67 (d, 1H, J = 16.0, H8); 6.34 (d, 1H,
J = 16.0, H10); 3.92 (d, 2H, J = 7.5, H12); 2.91 (s, 3H, 14-
CH3); 2.04 (m, 2H, 4-CH2); 1.76 (s, 3H, 5-CH3); 1.58 (m,