Isolation of macrocyclic metacyclophanes from the attempted synthesis of [7.0]metacyclophanes of the myricanone series by Thorpe-Ziegler - Intramolecular cyclization of diaryls substituted by ω-cyanoalkyl chains

Article abstract of DOI:10.1002/(SICI)1099-0690(200004)2000:8<1527::AID-EJOC1527>3.0.CO;2-G

The syntheses of the diaryls 14 and 21, substituted by two ω-cyanoalkyl chains (one on each ring), are described. Treatment of the unsymmetrical diaryl 14 with NaN(Me)Ph in a Thorpe-Ziegler reaction failed to give any definite product. Under the same conditions the symmetrical diaryl 21 led to an isomeric mixture of dimeric enaminonitriles 24. Mild acidic hydrolysis of the latter yielded the isomeric β-ketonitriles 25, whereas more drastic hydrolytic conditions led to the macrocyclic diketone 26.

Full text of DOI:10.1002/(SICI)1099-0690(200004)2000:8<1527::AID-EJOC1527>3.0.CO;2-G

FULL PAPER
Isolation of Macrocyclic Metacyclophanes From the Attempted Synthesis of
[7.0]Metacyclophanes of the Myricanone Series by Thorpe–Ziegler –
Intramolecular Cyclization of Diaryls Substituted by ω-Cyanoalkyl Chains
[a]
[a]
[a]
[a]
´ ´
Benedicte Dansou, Christophe Pichon, Robert Dhal, Eric Brown,* and
[a]
´
Stephane Mille
Keywords: [7.0]Metacyclophanes / Myricanone / Diaryls / Suzuki reaction / Dinitriles / Thorpe–Ziegler condensation
The syntheses of the diaryls 14 and 21, substituted by two ω-
an isomeric mixture of dimeric enaminonitriles 24. Mild
cyanoalkyl chains (one on each ring), are described. Treat- acidic hydrolysis of the latter yielded the isomeric β-ketoni-
ment of the unsymmetrical diaryl 14 with NaN(Me)Ph in a triles 25, whereas more drastic hydrolytic conditions led to
Thorpe–Ziegler reaction failed to give any definite product.
the macrocyclic diketone 26.
Under the same conditions the symmetrical diaryl 21 led to
Introduction
(2) (Figure 2) by Whiting and his co-workers[3] in 1970 from
the stem bark of Myrica nagi, used in folk medicine, ap-
proximately 25 different diarylheptanoids of this type have
been reported. Related natural products such as porson,[4]
trideoxyasadaninene (3),[5] garugarin,[6] etc, have also been
identified from other plant sources.
Evidence has been accumulated suggesting that the linear
diarylheptanoids I are the biogenetic precursors of the mac-
rocyclic congeners II.[7] Therefore synthetic routes to type
II macrocycles, involving the cyclization of appropriate 1,7-
diarylheptanoids, were investigated. To our knowledge the
unique synthesis of myricanone (1) and myricanol (2) ac-
complished by Whiting et al. is based upon the Ni0-cata-
lyzed intramolecular diaryl coupling reaction of suitable lin-
ear diarylheptanoids.[8] This macrocyclization methodology
was developed by Semmelhack et al. for the synthesis of
alnusone.[9] Recently Zhu et al. described an intramolecular
SNAr reaction for the total synthesis of acerogenin-type
macrocycles.[10]
Diarylheptanoids represent a distinct class of naturally
occurring compounds which display the unique structural
feature of two hydroxylated aromatic rings linked by a lin-
ear seven-carbon chain. Within this class are linear (I) and
macrocyclic (II) diarylheptanoids. In the latter the aromatic
rings are connected to form a diaryl ether or a diaryl moiety
(Figure 1).[1] Most of the linear diarylheptanoids exhibit a
broad range of potent biological activities including anti-
inflammatory, antihepatotoxic, antifungal, antibacterial,
and related properties.[1] Very recently, compounds pos-
sessing an inhibitory activity against nitric oxide production
in activated murine macrophages have been isolated from
the seeds of A. blepharocalyx.[2]
A major drawback of Whiting’s syntheses of 1 and 2[8] is
the poor yields (7–10%) of the formation of the aryl-aryl
linkage in the final step. That is the reason why we consid-
ered using a synthetic scheme to [7.0]metacyclophanes
which involved the early formation of the aryl-aryl bond
followed by Thorpe–Ziegler cyclization (Scheme 1).
We report herein the synthesis of diaryls of type 5 and
also the first attempts of macrocyclization via Thorpe–
Ziegler condensation of meta-meta disubstituted (i) sym-
metrical diaryl bearing on each ring a cyanopropyl chain,
and (ii) unsymmetrical diaryl bearing on one of the rings a
cyanoethyl chain and on the second one a cyanobutyl
chain.
Figure 1. The various classes of natural diarylheptanoids
Most of the macrocyclic diarylheptanoids have been ex-
tracted from both plant families Betulaceae and Myrica-
cea.[1b] Since the isolation of myricanone (1) and myricanol
Results and Discussion
[a]
`
´
Laboratoire de Synthese Organique (ESA 6011), Faculte des
Synthesis of the Unsymmetrical Diaryldinitrile 14
Sciences,
Avenue Olivier Messiaen, F-72085 Le Mans Cedex 9, France
Fax: (internat.) ϩ 33-2/43833366
E-mail: lso@lola.univ-lemans.fr
The diaryldinitrile 14 was assumed to be a precursor for
O-methylmyricanone (4). Its synthesis was carried out as
Eur. J. Org. Chem. 2000, 1527Ϫ1533
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
1434Ϫ193X/00/0408Ϫ1527 $ 17.50ϩ.50/0
1527

B. Dansou, C. Pichon, R. Dhal, E. Brown, S. Mille
FULL PAPER
Figure 2. Some macrocyclic diarylheptanoids
Scheme 1. Synthesis of [7.0] metacyclophanes
Scheme 2. Synthesis of the unsymmetrical diaryldinitrile 14
described in Scheme 2. The known electron-rich arene- Synthesis of the Symmetrical Diaryldinitrile 21
boronic acid 7 was prepared from the corresponding aryl
bromide according to literature procedures.[11] Suzuki cross-
We next chose to synthesize a rather simple diaryl bear-
coupling reaction of bromo-p-anisaldehyde (6)[12] with the ing on each ring a cyanopropyl chain, as a potential pre-
areneboronic acid 7 in the presence of palladium(0), EtOH, cursor for trideoxyasadaninene (3). The diaryldicarbal-
and Na2CO3 as base, afforded the required diaryl 8 in 98% dehyde 16 was generated from the aryl iodide 15 by an
yield.[13] Cyanomethylenation of 8 in dioxane using the dir- Ullmann reaction (Scheme 3).
ect KOH-catalyzed condensation of acetonitrile with aro-
Treatment of 16 with triethyl phosphonoacetate accord-
[14]
matic aldehydes,
followed by reduction of the resulting ing to Wittig–Horner conditions smoothly afforded the di-
intermediate 9, gave the diaryl propanenitrile 10. Another ethylenic diester 17. Catalytic hydrogenation of 17 over a
alkyl nitrile chain was introduced via Friedel–Crafts acyl- Pd–C catalyst quantitatively gave the saturated diester 18.
ation of 10, followed by reductive deoxygenation of the ke- The latter was converted into the corresponding diol 19
tone function of the resulting intermediate 12, thus af- upon reduction with LiAlH4 in ether. Reaction of 19 with
fording the dinitrile 13. Protection of the phenolic hydroxyl tosyl chloride in the presence of pyridine yielded the ditos-
of the latter as benzyl ether afforded the diaryl 14 in 18% ylate 20, which was next converted into the desired dinitrile
overall yield.
21 by means of excess sodium cyanide in DMF. Alternat-
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Eur. J. Org. Chem. 2000, 1527Ϫ1533

Intramolecular Cyclization of Diaryls Substituted by ϖ-Cyanoalkyl Chains
FULL PAPER
Scheme 3. Synthesis of the symmetrical diaryldinitrile 21
ively, the dinitrile 21 was obtained in a one-pot reaction
by treatment of the diol 19 with trimethylsilyl chloride and
sodium cyanide in the presence of catalytic amounts of pot-
assium iodide.
Thorpe–Ziegler Reaction
The Thorpe–Ziegler intramolecular cyclization of the di-
nitrile 14 was next attempted using a variety of bases and
experimental conditions (Scheme 4). Thus, using sodium
methylphenylamide as a base in high dilution conditions,
led to a mixture of unidentified products which did not
correspond to the structures 22 or 23 although the IR spec-
tra indeed suggested that the nitrile groups (νCN ϭ 2244
cm–1) had been transformed into the requisite enaminonitr-
ile function (νCN ϭ 2179 cm–1). No further information
could be gained from the highly complex 1H NMR spectra.
Under similar conditions as above, the symmetrical dini-
trile 21 did not lead to the required cyclized monomeric
enaminonitrile compound. The IR and HR mass spectra
suggested that the reaction product had the dimeric struc-
ture 24. Here again the 1H NMR spectra were not ex-
ploitable. Hydrolysis of the compound(s) 24 under mild
conditions (2 HCl, room temp., 2 h) gave the dimeric bis-
β-ketonitrile 25 as evidenced from the IR and HR mass
spectra. The macrocyclic diketone 26 was obtained upon
Scheme 4. Thorpe–Ziegler reaction
hydrolysis of 22 under more drastic hydrolytic conditions,
1
as evidenced from IR, H and 13C NMR spectra.
which prevents both CH2CN subunits (of 14 or 21) from
coming close to one another.
Conclusion
We could not carry out the synthesis of [7.0] metacyclo-
phanes by ring closure of chain substituted diaryl units
(such as 14 and 21), the formation of dimeric compounds
Experimental Section
1
General: H and 13C NMR spectra were recorded in CDCl3 using
´
being the only detectable event. Parallel to our efforts Nog-
´
Bruker AC 400 (400 MHz), Bruker DPX 200 (200 MHz for 1H)
and (100 MHz for 13C) spectrometers. Chemical shifts are given
relative to TMS (δ ϭ 0), coupling constants in Hz. – IR spectra
were measured with Nicolet 5 DX and Genesis (Mattson) FFT
[15]
radi et al. have very recently reported the unwanted syn-
thesis of dimeric diarylheptanoids in their attempts at the
synthesis of acerogenins based upon the early formation of
aryl-aryl bond. All these failures might be due to the strain spectrometers. – Melting points were measured with a Reichert mi-
Eur. J. Org. Chem. 2000, 1527Ϫ1533 1529

B. Dansou, C. Pichon, R. Dhal, E. Brown, S. Mille
FULL PAPER
croscope. – Elemental analyses were performed by the Service de
Microanalyse du CNRS, Gif-sur-Yvette. – Mass spectra were run
reflux condenser, a nitrogen inlet, and a magnetic stirrer, were ad-
ded 85% powdered KOH (109 mg, 1.65 mmol) and dry acetonitrile
(1.4 mL). The mixture was heated to reflux and a solution of alde-
hyde 8 (500 mg, 1.65 mmol) in a 50:50 mixture of acetonitrile and
dioxane (5.5 mL) was added in one stream. After the addition was
complete, stirring was continued for 8 min and the hot solution was
poured onto cracked ice (35 mL). This mixture was extracted with
dichloromethane (4 ϫ 25 mL), dried over MgSO4 and evaporated
in vacuo. Flash chromatography of the crude product gave the di-
phenylpropenenitrile 9 (486 mg, 91%), m.p. 98–101 °C (E/Z: 9:1). –
IR (nujol): ν˜ ϭ 2923 (OCH3 Ar) cm–1, 2211(CϵN), 1596 (CϭC
´
with a Varian Mat 311 spectrometer by Service de Spectrometrie
´
de Masse Haute Resolution, University of Rennes. – All solvents
and reagents were purified and dried according to standard proced-
ures prior to use.
2,3,4-Trimethoxybenzeneboronic Acid (7):[16] 1-Bromo-2,3,4-trime-
thoxybenzene (7.35 g, 29.76 mmol) was added to a magnetically
stirred suspension of oven-dried magnesium turnings (1.084 g,
44.64 mmol) in THF (39 mL) kept under a nitrogen atmosphere.
The resulting mixture was heated at reflux for 90 min then cooled
to room temperature.
1
Ar), 1213 (C–O), 1103 (C–O), 1010 (C–O). – H NMR (400 MHz,
CDCl3): E Isomer (90%): δ ϭ 3.73 (s, 3 H, OCH3), 3.83 (s, 3 H,
OCH3), 3.90 (s, 6 H, 2 OCH3), 5.75 (d, J ϭ 16.6 Hz, 1 H), 6.73 (d,
J ϭ 8.5 Hz, 1 H), 6.91 (d, J ϭ 8.5 Hz, 1 H), 6.97 (d, J ϭ 8.6 Hz,
1 H), 7.35 (d, J ϭ 16.6 Hz, 1 H), 7.44 (d, J ϭ 2.3 Hz, 1 H), 7.48
(dd, J ϭ 8.6, J ϭ 2.3 Hz, 1 H). – Z Isomer (10%): δ ϭ 3.73 (s, 3
H, OCH3), 3.83 (s, 3 H, OCH3 ), 3.90 (s, 6 H, 2 OCH3), 5.30 (d,
J ϭ 12.1 Hz, 1 H), 6.73 (d, J ϭ 8.5 Hz, 1 H), 6.91 (d, J ϭ 8.5 Hz,
1 H), 6.97(d, J ϭ 8.6 Hz, 1 H), 7.05 (d, J ϭ 12.1 Hz, 1 H), 7.58 (d,
J ϭ 2.3 Hz, 1 H), 7.95 (dd, J ϭ 8.6 Hz, J ϭ 2.3 Hz, 1 H). –
C19H19NO4 (325.331): calcd. C 70.14, H 5.89, N 4.30, O 19.67;
found C 69.94, H 6.06, N 4.11, O 19.89.
THF (12 mL) was put in a three-necked, oven-dried flask equipped
with a magnetic stirrer and a low-temperature thermometer, and
kept under an atmosphere of dry nitrogen. The reaction vessel was
cooled to –60 °C, then trimethyl borate (3.36 mL, 29.76 mmol) and
the freshly prepared aryl Grignard reagent (29.76 mmol) in THF
(39 mL) were added simultaneously (but independently), in a drop-
wise fashion to ensure that the reaction mixture was kept at –60
°C throughout the addition, and that equimolar quantities of each
reagent were present in the reaction vessel at all times. After the
addition, the reaction mixture was stirred at –60 °C for a further
30 min, then it was warmed to room temperature and stirred for
30 min more. It was acidified to pH 6–7 with 6  HCl (30 mL)
(while maintaining the temperature below 5 °C) and extracted with
diethyl ether (4 ϫ 50 mL). The combined ether layers were washed
with brine (50 mL) and dried over MgSO4. After removal of the
solvent the areneboronic acid 7 (6.3 g, 90%) was obtained with 90%
purity (ref.[11] 73%), m.p.70–72 °C (water). – IR (film): ν˜ ϭ 3350
5Ј-(2-Cyanoethyl)-2,2Ј,3,4-tetramethoxydiphenyl (10):[16] To a solu-
tion of diphenylpropenenitrile 9 (440 mg, 1.35 mmol) in methanol
(11 mL), magnesium turnings (658 mg, 27.66 mmol) were added
cautiously in portions. An oversized flask and an efficient ice/water
cooling bath were required to control the foaming from the vigor-
ous exothermic reaction. The mixture was stirred for 5 h and then
acidified with 6  HCl and extracted with dichloromethane (4 ϫ
25 mL). The combined organic layers were dried over MgSO4. Re-
moval of the solvent gave the crude compound 10 (335 mg, 80%),
m.p. 102–103 °C. – IR (film CDCl3): ν˜ ϭ 2938 (OCH3 Ar) cm–1,
2246 (CϵN), 1598 (CϭC Ar), 1214 (C–O), 1103 (C–O), 1018 (C–
1
cm–1, 1596, 1469, 1344, 1290. – H NMR (200 MHz, CDCl3): δ ϭ
3.86 (s, 3 H, OCH3), 3.90 (s, 3 H, OCH3), 4.08 (s, 3 H, OCH3),
6.38 [s, 2 H, B(OH)2], 6.74 (d, J ϭ 9.0 Hz, 1 H), 7.53 (d, J ϭ
9.0 Hz, 1 H).
2,2Ј,3Ј,4Ј-Tetramethoxydiphenyl-5-carbaldehyde (8):[16] To a suspen-
1
O). – H NMR (400 MHz, CDCl3): δ ϭ 2.62 (t, J ϭ 7.3 Hz, CH2,
sion
of
tetrakis(triphenylphosphane)palladium
(327 mg,
2 H), 2.93 (t, J ϭ 7.3 Hz, CH2, 2 H), 3.72 (s, 3 H, OCH3), 3.78 (s,
3 H, OCH3), 3.90 (s, 6 H, 2 OCH3), 6.72 (d, J ϭ 8.6 Hz, 1 H), 6.93
(d, J ϭ 8.6 Hz, 1 H) and (d, J ϭ 8.6 Hz, 1 H), 7.08 (d, J ϭ 2.3 Hz,
1 H), 7.20 (dd, J ϭ 8.6 Hz, J ϭ 2.3 Hz, 1 H). – HRMS
(C19H21NO4): calcd. 327.1470; found 327.1467. – C19H21NO4
(327.345): calcd. C 69.71, H 6.47, N 4.28; found C 69.28, H 6.24,
N 4.26.
0.283 mmol) in anhydrous and degassed DME (50 mL) was added
3-bromo-p-anisaldehyde 6[12] and the mixture was stirred for 10 min
at room temperature. To this solution were sequentially added the
areneboronic acid 7 (3.4 g, 14.14 mmol) in ethanol (8.5 mL) and 2
 aqueous Na2CO3 (9.43 mL, 18.86 mmol), and the mixture was
refluxed for 18 h, cooled and filtered. The filtrate was evaporated
to dryness and the residue was treated with brine (50 mL) and
dichloromethane (50 mL), and then extracted with dichlorome-
thane (3 ϫ 50 mL). The combined organic layers were dried over
MgSO4. After removal of the solvent, the residue was triturated
under toluene (30 mL) to induce crystallization of the diphenyl 8.
The supernatant solution was concentrated and chromatographed
(toluene/methanol) thus affording a second crop of diphenyl 8[13]
(total yield: 2.80 g, 98%), m.p. 158–159 °C. – IR (nujol): ν˜ ϭ 2929
(OCH3, Ar) cm–1, 1687 (CHO), 1594 (CϭC Ar), 1457 (CH3), 1213
4-Cyanobutanoyl Chloride (11):[16] To a stirred mixture of acrylon-
itrile (26.6 mL, 400 mmol) and isopropylidene malonate (28.8 g,
200 mmol) in dry dichloromethane (250 mL) was added dropwise
triethylamine (29.5 mL, 220 mmol) for 15 min. The mixture was
stirred for 92 h at 60 °C, cooled, then acidified with 10% HCl
(200 mL), and extracted with dichloromethane (3 ϫ 150 mL). The
combined organic layers were washed with brine (150 mL) and
dried over MgSO4. After removal of the solvent crude 5-(2-cyano-
ethyl)-2,2-dimethyl-1,3-dioxan-4,6-dione (34 g, 86%), was obtained,
m.p 115–116 °C (ref.[17] m.p. 123–124 °C). – IR (nujol): ν˜ ϭ 2250
(CϵN) cm–1, 1784 (CϭO, lactone), 1739 (CO–O–). – 1H NMR
(200 MHz, CDCl3): δ ϭ 1.77 (s, 3 H), 1.85 (s, 3 H), 2.45 (m, 2 H),
2.77 (t, J ϭ 7.2 Hz, 2 H), 3.70 (t, J ϭ 5.8 Hz, 1 H).
1
(C–O), 1101 (C–O), 1006 (C–O). – H NMR (400 MHz, CDCl3):
δ ϭ 3.73 (s, 3 H, OCH3), 3.89 (s, 3 H, OCH3), 3.91 (s, 6 H, 2
OCH3), 3.91 (s, 6 H, 2 OCH3), 6.73 (d, J ϭ 8.5 Hz, 1 H), 6.93 (d,
J ϭ 8.5 Hz, 1 H), 7.07 (d, J ϭ 8.5 Hz, 1 H), 7.75 (d, J ϭ 2.0 Hz,
1 H), 7.88 (dd, J ϭ 8.5 Hz, J ϭ 2.0 Hz, 1 H), 9.91 (s, 1 H, CHO). –
13C NMR (100 MHz, CDCl3): δ ϭ 55.9 (CH3–O), 55.95 (CH3–O),
60.7 (CH3–O), 60.9 (CH3–O), 106.9, 110.6, 125.1, 123.9, 125.1,
128.3, 129.5, 131.3, 133.1, 142.0, 151.7, 153.6, 162.1, 190.9. –
C17H18O5 (302.296): calcd. C 67.54, H 6.00, O, 26.46; found C
67.39, H 5.96, O 26.40.
This unpurified compound was then dissolved in water/pyridine
(17 mL:170 mL) containing Cu powder (1.7 g, 26.56 mmol) and
heated under reflux for 3 h. The mixture was cooled and then the
Cu was removed by filtration, and the filtrate acidified to pH 1–2
with 6  HCl. The residue was saturated with ammonium sulfate
5Ј-(2-Cyanovinyl)-2,2Ј,3,4-tetramethoxydiphenyl (9):[16] In a 250 mL then extracted with diethyl ether and dried over MgSO4. Evapora-
three-necked round-bottomed flask, equipped with a tap funnel, a
tion of the solvent gave crude 4-cyanobutanoic acid (9.24 g, 94%),
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Eur. J. Org. Chem. 2000, 1527Ϫ1533

Intramolecular Cyclization of Diaryls Substituted by ϖ-Cyanoalkyl Chains
FULL PAPER
m.p. 45–46 °C (ref.[18] m.p.45–50 °C). – IR (film): ν˜ ϭ 3482–2653
K2CO3 (225 mg, 1.64 mmol) and KI (7 mg, 0.043 mmol) in dry
(O–H) cm–1, 2250 (CϵN), 1712 (CϭO). – 1H NMR (400 MHz acetone (12 mL) was added benzyl chloride (189 µL, 1.64 mmol)
CDCl3): δ ϭ 2.00 (quint., J ϭ 7.0 Hz, 2 H), 2.49 (t, J ϭ 7.0 Hz, 2
H), 2.56 (t, J ϭ 7.0 Hz, 2 H), 8.40 (s, 1 H, CO2H).
dropwise. The mixture was heated at reflux for 18 h. The cooled
solution was filtered and evaporated, thus affording crude com-
pound 14 (527 mg, 100%). – IR (film CDCl3): ν˜ ϭ 2921 (OCH3
Ar) cm–1, 2247 (CϵN), 1600 (C–O). –1H NMR (400 MHz,
CDCl3): δ ϭ 1.65 (m, 4 H), 2.25 (t, J ϭ 6.8 Hz, 2 H), 2.60 (t, J ϭ
7.3 Hz, 4 H), 2.92 (t, J ϭ 7.3 Hz, 2 H), 3.70 (s, 3 H, OCH3), 3.78
(s, 3 H, OCH3), 3.92 (s, 3 H, OCH3), 5.08 (s, 2 H, OCH2Ph), 6.75
(s, 1 H), 6.92 (d, J ϭ 8.4 Hz, 1 H), 7.07 (d, J ϭ 2.3 Hz, 1 H), 7.21
(dd, J ϭ 8.4 Hz, J ϭ 2.3 Hz, 1 H), 7.40 (m, 5 H, Ph). – 13C NMR
(100 MHz, CDCl3): δ ϭ 16.9 (CH2), 19.6, 25.0, 29.0, 29.05, 30.7,
55.6 (OCH3), 60.8 and 60.85 (OCH3), 75.2, 111.1, 119.2, 119.8,
127.4, 127.7, 126.0, 127.9, 128.45, 128.5, 128.7, 129.7, 129.8, 131.3,
137.9, 146.1, 150.2, 150.25, 156.0. – HRMS (C30H32N2O4): calcd.
484.2362; found 484.2371.
To a stirred solution of 4-cyanobutanoic acid (3.63 g, 33.12 mmol)
in dry dichloromethane (37 mL) was added dropwise oxalyl chlor-
ide (2.96 mL, 99.36 mmol) at room temperature. The mixture was
then gently refluxed overnight. Removal of the solvent gave 4-cy-
anobutanoyl chloride (11) (4.05 g, 96%)[19] which was used without
further purification. – IR (film): ν˜ ϭ 2254 (CϵN) cm–1, 1791 (Cϭ
O). –1H NMR (200 MHz, CDCl3): δ ϭ 2.08 (quint., J ϭ 7.0 Hz,
2 H, CH2), 2.56 (t, J ϭ 7.0 Hz, 2 H, CH2), 3.15 (t, J ϭ 7.0 Hz, 2
H, CH2).
5-(4-Cyanobutanoyl)-5Ј-(2-cyanoethyl)-4-hydroxy-2,2Ј,3-trimeth-
oxydiphenyl (12):[16] In a 250 mL three-necked round-bottomed
flask, equipped with a tap funnel, a nitrogen inlet, and a magnetic
stirrer, was placed a solution of AlCl3 (978 mg, 7.33 mmol) in nitro-
benzene (7 mL). A mixture of biarylpropanenitrile 10 (400 mg,
1.22 mmol) and crude acyl chloride 11 (970 mg, 7.33 mmol) in
nitrobenzene (6 mL) was added dropwise at 18 °C. The reaction
mixture was stirred at room temperature for 4 h then acidified with
10% HCl (10 mL) and extracted with dichloromethane (3 ϫ
20 mL). The combined organic layers were washed with brine, dried
over MgSO4 and the solvents evaporated. Removal of the nitroben-
zene by distillation (ഠ 10–1Torr at 40–45 °C) gave a mixture
(687 mg) of starting material 10, the dinitrile 12, and aliphatic by-
products. Flash chromatography (toluene/ethyl acetate 90:10) gave
a first fraction of 12 (137 mg). The chromatographic core was ex-
tracted with a 10% solution of NaOH. The aqueous layer was
acidified with 10% HCl and then extracted with dichloromethane.
The CH2Cl2 extracts were dried over MgSO4 and evaporated, thus
affording a second crop of dinitrile 12 (40 mg) (total: 177 mg, 45%
yield with respect to the recovered unchanged starting material
10). – IR (film CDCl3): ν˜ ϭ 2921 (OH phenol) cm–1, 2852 (OCH3
3-Iodo-4-methoxybenzaldehyde (15): To a magnetically stirred solu-
tion of 4-methoxybenzaldehyde (8.91 g, 65 mmol) and dry silver
trifluoroacetate (16.35 g, 74 mmol) in dichloromethane (250 mL),
maintained under a nitrogen atmosphere was added iodine (13.33
g, 83.34 mmol) in small portions over 15 min. After stirring the
resulting mixture for 24 h, the latter was filtered and the precipit-
ated silver iodide was washed with dichloromethane. The combined
filtrates were washed with a 10% solution of Na2S2O3 and dried
over MgSO4. After removal of the solvent, the residue was tritur-
ated under diethyl ether to induce crystallization of the iodide 15
(15.80 g, 99%), m.p. 106–107 °C (ref.[20] 42%, m.p. 105–107 °C). –
IR (nujol): ν˜ ϭ 1673 (CHO) cm–1, 1590 (CϭC, Ar), 1274, 1182,
1016 (CO). – 1H NMR (400 MHz, CDCl3): δ ϭ 3.98 (s, 3 H,
OCH3), 6.93 (d, J ϭ 8.5 Hz, 1 H), 7.86 (dd, J ϭ 8.5 Hz, J ϭ 2 Hz,
1 H), 8.31 (d, J ϭ 2 Hz, 1 H), 9.82 (s, 1 H, CHO).
2,2Ј-Dimethoxydiphenyl-5,5Ј-bicarbaldehyde (16): To the molten
aryl iodide 15 (499 mg, 1.91 mmol) was added an excess of activ-
ated Cu powder.[21] The sealed tube was heated to 180 °C for 5 h.
The cooled reaction mass was then triturated with dichloromethane
and the Cu was removed by filtration. After removal of the solvent,
the residue was triturated under diethyl ether to induce crystalliza-
tion of the bicarbaldehyde 16 (244 mg, 62%), m.p. 134 °C (ref.[20a]
12%, m.p. 131–132 °C).
1
Ar), 2246 (CϵN), 1637 (CϭO ketone Ar). – H NMR (200 MHz,
CDCl3): δ ϭ 2.10 (m, 2 H), 2.52 (t, J ϭ 7.1 Hz, 2 H), 2.65 (t, J ϭ
6.9 Hz, 2 H), 2.95 (t, J ϭ 7.1 Hz, 2 H), 3.15 (t, J ϭ 6.9 Hz, 2 H),
3.79 (s, 3 H, OCH3), 3.89 (s, 3 H, OCH3), 3.93 (s, 3 H, OCH3),
6.92 (d, J ϭ 8.4 Hz, 1 H), 7.07 (d, J ϭ 2.3 Hz, 1 H), 7.23 (dd, J ϭ
8.4 Hz, J ϭ 2.3 Hz, 1 H), 7.38 (s, 1 H), 12.45 (s, 1 H, OH). –
HRMS (C23H24N2O5): calcd. 408.1685; found 408.1678.
(E,E)-5,5Ј-Bis[2-(ethoxycarbonyl)vinyl]-2,2Ј-diphenyl (17): K2CO3
(1.84 g, 7 mmol), triethyl phosphonoacetate (3 g, 7 mmol), bicarb-
aldehyde 16 (1.51 g, 3.68 mmol), dioxane (7 mL) and water (120
µL) were stirred at 85 °C for 2 h. More K2CO3 (1.84 g, 7 mmol)
and triethyl phosphonoacetate (3 g, 7 mmol) were then added at
room temperature. The temperature was then increased to 85 °C
for 3 additional hours. The mixture was then diluted with water,
acidified to pH 5–6 with 10% HCl, and extracted with dichlorome-
thane (5 ϫ 20 mL). The combined organic layers were washed with
a saturated solution of K2CO3 (3 ϫ 20 mL) then with water (2 ϫ
20 mL), and dried over MgSO4. After removal of the solvent, the
residue was triturated under diisopropyl ether to induce crystalliza-
tion. Recrystallization from diethyl ether gave the diphenyl 17
(2.38 g, 86%), m.p. 146–147 °C (ref.[22] oily product). – IR (KBr):
ν˜ ϭ 1703 (CϭO) cm–1, 1633 (CϭC), 1252 (CO ether), 1165 (CO
5-(4-Cyanobutyl)-5Ј-(2-cyanoethyl)-4-hydroxy-2,2Ј,3-trimethoxy-
diphenyl (13):[16] To a magnetically stirred solution of ketone 12
(129 mg, 0.31 mmol) and boron trifluoride–diethyl ether (246 µL,
1.89 mmol) in dry THF (3 mL) was added sodium cyanoborohyd-
ride (84 mg, 1.26 mmol). The reaction mixture was stirred at room
temperature for 48 h then at 50 °C for 8 h. After completion of the
reaction (monitored by TLC), the mixture was diluted with ethyl
ether (10 mL), washed with saturated aqueous Na2CO3 (3 ϫ
10 mL) and dried over MgSO4. After removal of the solvent, fol-
lowed by chromatography of the residue (toluene/ethyl acetate
80:20 with methanol traces), the reduced compound 13 (78 mg,
64%) was obtained. – IR (film CDCl3): ν˜ ϭ 3411 (OH) cm–1, 2921
(OCH3 Ar), 2246 (CϵN). – 1H NMR (400 MHz, CDCl3): δ ϭ 1.75
(m, 4 H), 2.33 (t, J ϭ 7.1 Hz, 2 H), 2.60 (m, 4 H), 2.90 (t, J ϭ
7.3 Hz, 2 H), 3.61 (s, 3 H, OCH3), 3.75 (s, 3 H, OCH3), 3.91 (s, 3
H, OCH3), 5.85 (s, 1 H, OH), 6.67 (s, 1 H, H-6), 6.90 (d, J ϭ
8.4 Hz, 1 H, H-3Ј), 7.09 (d, J ϭ 2.4 Hz, 1 H, H-6Ј), 7.20 (dd, J ϭ
8.4 Hz, J4Ј-6Ј ϭ 2.4 Hz, 1 H). – HRMS (C23H26N2O4): calcd.
394.1892; found 394.1890.
1
ester). – H NMR (400 MHz, CDCl3): δ ϭ 1.32 (t, J ϭ 7.1 Hz, 6
H, 3 CH2), 3.80 (s, 6 H, 2 OCH3), 4.24 (q, J ϭ 7.1 Hz, 4 H, 2
CH2), 6.33 (d, J ϭ 16.0 Hz, 2 H), 6.98 (d, J ϭ 8.5 Hz, 2 H), 7.43
(d, J ϭ 2.3 Hz, 2 H), 7.52 (dd, J ϭ 16.0 Hz, J ϭ 2.3 Hz, 2 H), 7.67
(d, J ϭ 16.0 Hz, 2 H).
4-Benzyloxy-5-(4-cyanobutyl)-5Ј-(2-cyanoethyl)-2,2Ј,3-trimethoxy-
diphenyl (14):[16] To a mixture of phenol 13 (430 mg, 1.09 mmol),
5,5Ј-Bis[2-(ethoxycarbonyl)ethyl]-2,2Ј-dimethoxydiphenyl (18):
magnetically stirred solution of unsaturated diester 17 (730 mg,
A
Eur. J. Org. Chem. 2000, 1527Ϫ1533
1531

B. Dansou, C. Pichon, R. Dhal, E. Brown, S. Mille
FULL PAPER
1.78 mmol) in ethanol (25 mL) was hydrogenated at 4 bar with 10%
Isomeric Mixture of Enaminonitriles (24):[16] The procedure of Mar-
Pd/C catalyst at 45 °C for 5 h. After filtering off the catalyst and shall[23] was modified. To a stirred mixture of sodium hydride
evaporating the solvent, compound 18 was obtained as a yellow oil
(73 mg, 1.82 mmol), (oil removed by washing with pentane) in THF
(734 mg, 100%) in agreement with ref.[22] – IR (KBr): ν˜ ϭ 1734 (10 mL) was added N-methylaniline (227 µL, 2.1 mmol). The mix-
(CϭO) cm–1, 1608 (CϭC), 1244 (CO, ether), 1182 (CO, ester). – ture was warmed to reflux for 2–3 h whereupon the dinitrile 21
1H NMR (400 MHz, CDCl3): δ ϭ 1.24 (t, J ϭ 7.1 Hz, 6 H), 2.62
(50 mg, 0.14 mmol) in THF (2 mL) was added to the refluxing so-
(t, J ϭ 7.9 Hz, 4 H), 2.92 (t, J ϭ 7.9 Hz, 4 H), 3.74 (s, 6 H, 2 lution in a regular and dropwise fashion. The solution was cooled
OCH3), 4.13 (q, J ϭ 7.1 Hz, 4 H), 6.88 (d, J ϭ 8.4 Hz, 2 H), 7.06
(d, J ϭ 2.3 Hz, 2 H), 7.15 (dd, J ϭ 8.4, J ϭ 2.3 Hz, 2 H).
to room temperature, hydrolyzed with 1  HCl (2 mL), diluted with
water (15 mL), and was then extracted with diethyl ether. The com-
bined organic layers were washed with brine and then dried over
MgSO4. Removal of the solvent, followed by chromatography of
the residue (toluene/ethyl acetate) gave a mixture of enaminonitriles
24 as a yellow powder (14 mg, 28%), m.p. 80–85 °C. – IR (film
CDCl3): ν˜ ϭ 3471, 3363, 3255 (NH2) cm–1, 2179 (CϵN), 1641 (Cϭ
C), 1602 (δNH2). – 1H NMR (400 MHz, CDCl3): Complicated
spectrum not possible to interpret. – HRMS (C44H48N4O4): calcd.
697.3754; found 697.3727.
5,5Ј-Bis(3-hydroxypropyl)-2,2Ј-dimethoxydiphenyl (19): To a suspen-
sion of LiAlH4 (0.73 g, 19.3 mmol) in dry diethyl ether (750 mL),
maintained under a nitrogen atmosphere and kept in an ice/water
cooling bath, was added dropwise a solution of diester 18 (1.6 g,
3.86 mmol) in diethyl ether (25 mL). After the reaction was com-
plete, the reaction mixture was stirred at reflux for 5 h then it was
cooled to 0 °C. Methanol (20 mL) and water (50 mL) were then
added dropwise successively. The aqueous layer was acidified to pH
5–6 with 10% HCl and was extracted with dichloromethane (5 ϫ
25 mL). The combined organic layers were washed with brine (2 ϫ
20 mL) and dried over MgSO4. Removal of the solvent gave com-
pound 19 (1.26 g, 100%). – IR (film): ν˜ ϭ 3367 (OH) cm–1, 1504
(CϭC), 1261 (CO, alcohol), 1242 (CO, ether). – 1H NMR
(400 MHz, CDCl3): δ ϭ 1.59 (br s, 2 H), 1.90 (m, 4 H), 2.68 (t, J ϭ
7.6 Hz, 4 H), 3.69 (t, J ϭ 6.4 Hz, 4 H), 3.75 (s, 6 H, 2 OCH3), 6.89
(d, J ϭ 8.4 Hz, 2 H), 7.07 (d, J ϭ 2.2 Hz, 2 H), 7.15 (dd, J ϭ 8.4
Hz, J ϭ 2.2 Hz, 2 H).
Isomeric Mixture of β-Ketonitriles (25):[16] The crude mixture of
enaminonitriles 24 (14 mg) was treated with 6  HCl (1 mL), di-
luted with water, and extracted with diethyl ether. The combined
organic layers were washed with 10% Na2CO3 solution and then
dried over MgSO4. Removal of the solvent, followed by chromato-
graphy of the residue (toluene/ethyl acetate) gave the β-ketonitrile
25 as a yellow powder (10 mg, 20% with respect to the dinitrile 21),
m.p. 200–210 °C. – IR (film CDCl3): ν˜ ϭ 2247 (CϵN) cm–1, 1726
(CϭO). – 1H NMR (400 MHz, CDCl3): Complicated spectrum not
possible to interpret. – HRMS (C44H46N2O6): calcd. 698.3349;
found 698.3356.
5,5Ј-Bis[3-p-toluenesulfonyloxy(propyl)-2,2Ј-dimethoxydiphenyl (20):
To a mixture of compound 19 (120 mg, 0.36 mmol), pyridine (97
µL, 1.16 mmol) and chloroform (1.3 mL) maintained at 0 °C, was
added tosyl chloride (165 mg, 0.86 mmol) in small portions over
15 min. The resulting mixture was stirred for 4 h at 0 °C, diluted
with dichloromethane (10 mL), and washed with 10% HCl (10 mL)
then with a saturated solution of K2CO3 (10 mL). The organic layer
was dried over MgSO4. Removal of the solvents gave the crude
compound 20 which was recrystallized from diisopropyl ether
(120 mg, 91%), m.p. 121–123 °C. – IR (nujol): ν˜ ϭ 1598 (CϭC)
cm–1, 1356 (SO3), 1244 (CO, ether). – 1H NMR (400 MHz, CDCl3):
δ ϭ 1.95 (m, 4 H), 2.41 (s, 6 H), 2.62 (t, J ϭ 6.4 Hz, 4 H), 3.72 (s,
6 H), 4.07 (t, J ϭ 6.2 Hz, 4 H), 6.85 (d, J ϭ 8.4 Hz, 2 H), 6.97 (d,
J ϭ 2.3 Hz, 2 H), 7.03 (dd, J ϭ 2.2 Hz, J ϭ 8.4 Hz, 2 H), 7.31 (d,
J ϭ 8.3 Hz, 4 H), 7.78 (d, J ϭ 8.3 Hz, 4 H). – 13C NMR (100 MHz,
CDCl3): δ ϭ 21.7 (2 CH3), 30.6, 55.8 (2 OCH3), 69.9 (CH2OSO2),
111.2, 127.7, 127.9, 128.4, 129.9, 131.4, 132.0, 133.1, 144.8, 155.5.
Diketone (26):[16] A stirred crude mixture of enaminonitriles 24
(50 mg) in 12  HCl (2 mL) was heated at reflux for 24 h, cooled,
diluted with water, and extracted with diethyl ether. The combined
organic layers were washed with 10% Na2CO3 solution and then
dried over MgSO4. Removal of the solvent, followed by chromato-
graphy of the residue (toluene/ethyl acetate) gave the diketone 26
as a yellow oily product (6 mg, 15% with respect to the dinitrile
21). – IR (film CDCl3): ν˜ ϭ 1710 (CϭO) cm–1. – 1H NMR
(400 MHz, CDCl3): δ ϭ 7.03 (dd, J ϭ 8.3 Hz, J ϭ 2.3 Hz, 4 H),
6.91 (d, J ϭ 2.3 Hz, 4 H), 6.80 (d, J ϭ 8.3 Hz, 4 H), 3.67 (s, 12 H,
4 OCH3), 2.53 (m, 8 H, 4 CH2CO), 2.33 (m, 8 H, 4 CH2Ar), 1.85
(m, 8 H, 4 CH2). – 13C NMR (100 MHz, CDCl3): δ ϭ 215.0 (CO),
155.40, 133.25, 131.49, 128.31, 127.83, 111.05, 55.81 (CH3–O),
41.94 (CH2–CO), 34.17 (CH2–Ar), 25.42 (CH2).
[1] [1a]
´
´
G. M. Keserü, M. Nogradi, The Chemistry of Natural Di-
5,5Ј-Bis(3-cyanopropyl)-2,2Ј-dimethoxydiphenyl (21): To a solution
of the ditosylate 20 (136 mg, 0.22 mmol) in DMF (2 mL) at room
temperature was added sodium cyanide (52 mg, 0.88 mmol). The
mixture was heated at 85 °C for 5 h, cooled to room temperature,
then diluted with dichloromethane (20 mL). The excess cyanide was
removed by filtration. The filtrate was washed with a 10% solution
of K2CO3 then with water (10 mL), and dried over MgSO4. Re-
moval of the solvents gave the crude compound 21 which was
recrystallized from diethyl ether (74 mg, 96%), m.p. 94–95 °C. – IR
(nujol): ν˜ ϭ 2245 (CN) cm–1, 1608 (CϭC), 1356 (SO3), 1240 (CO,
arlheptanoids, in Studies in Natural Products Chemistry (Ed.:
Atta-Ur-Rahman), Elsevier Science B. V., New-York, 1995, 17,
[1b]
357. –
P. Cleason, P. Tuchinda, V. Reutrakul, J. Indian
Chem. Soc. 1994, 71, 509.
[2]
[3]
[4]
[5]
[6]
P. J. Kumar, T. Yasuhiro, H. Koji, B. Purusotam, D. Hui, N.
Tsuneo, K. Shigetoshi, Biol. Pharm. Bull. 1998, 21, 371.
P. J. Begley, R. V. M. Campbell, L. Crombie, B. Tuck, D. A.
Whiting, J. Chem. Soc. (C) 1971, 3634.
T. Anthonsen, G. B. Lorentzen, K. E. Malterud, Acta Chem.
Scand., Ser. B 1975, 29, 529.
M. Yasue, Ringyo Shinkenjo Kenkyu Hokoku 1968, 209, 77;
Chem. Abstr. 1969, 70, 48743s.
1
ether). – H NMR (400 MHz, CDCl3): δ ϭ 1.98 (m, 4 H), 2.35 (t,
[6a] A. K. Mishra, M. M. Haribal, B. K. Sabata, Phytochemistry
J ϭ 7.1 Hz, 4 H), 2.76 (t, J ϭ 7.4 Hz, 4 H), 3.75 (s, 6 H, 2 OCH3),
6.91 (d, J ϭ 8.4 Hz, 2 H), 7.05 (d, J ϭ 2.3 Hz, J ϭ 8.4 Hz, 2 H),
7.13 (dd, J ϭ 8.4 Hz, J ϭ 2.3 Hz, 2 H). – 13C NMR (200 MHz,
CDCl3): δ ϭ 16.0 (CH2CN), 26.8 (CH2), 33.2 (CH2), 55.5 (OCH3),
111.1, 119.5 (CN), 127.3, 128.3, 131.1, 131.2, 155.3. – C22H24N2O2
(348.404): calcd. C 75.83, H 6.94, N, 8.04; found C 75.25, H 6.91,
N 7.96.
[6b]
1985, 24, 2463. –
M. M. Haribal, A. K. Mishra, B. K.
[6c]
Sabata, Phytochemistry 1985, 24, 4949. –
A. K. Mishra, P. S. Thombare, B. K. Sabata, Phytochemistry
1993, 33, 1221.
G. Venkatraman,
[7] [7a]
P. J. Roughley, D. A. Whiting, Tetrahedron Lett. 1971,
3741. – [7b] P. J. Roughley, D. A. Whiting, J. Chem. Soc., Perkin
Trans.1 1973, 2379. – [7c] T. Inoue, N. Kenmochi, N. Furukawa,
M. Fujita, Phytochemistry 1987, 26, 1409.
1532
Eur. J. Org. Chem. 2000, 1527Ϫ1533

Intramolecular Cyclization of Diaryls Substituted by ϖ-Cyanoalkyl Chains
FULL PAPER
´
[8] [8a]
[15]
´
´
A. D. Whiting, A. F. Wood, Tetrahedron Lett. 1978, 26,
M. Nogradi, G. M. Keserü, M. Kajtar-Peredy, B. Vermes, N.
Thi Thu Ha, Z. Dinya, ACH-Models Chem. 1998, 135, 57.
This procedure is part of B. Dansou’s Ph. D. thesis.
C. Chan, X. Huang, Synthesis 1984, 224.
[8b]
2335. –
A. D. Whiting, A. F. Wood, J. Chem. Soc., Perkin
[16]
[17]
Trans. 1 1980, 623.
[9] [9a]
M. F. Semmelhack, L. S. Ryono, J. Am. Chem. Soc.1975,
[9b]
[18] [18a]
97, 3873. –
M. F. Semmelhack, P. Helquist, L. D. Jones, L.
F. Foubelo, F. Uoret, M. Yus, Tetrahedron Lett. 1993, 49,
[18b]
Keller, L. Mendelson, L. S. Ryono, J. Gorzynski, R. D.
8465. –
Dictionary of Organic Compounds, 5th ed., Chap-
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man and Hall (New York), 1982, Vol. 2, 1326.
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[19]
G. I. Gonzalez, J. Zhu, J. Org. Chem. 1999, 64, 914.
W. S. Marshall, S. K. Sigmund, C. A. Whitesitt, S. L. Lifer, C.
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M. G. Banwell, J. M. Cameron, M. P. Callis, G. T. Crisp,
R. W. Gable, E. Hamel, J. N. Lambert, M. F. Mackay, M. E.
Reum, J. A. Scoble, Aust. J. Chem. 1991, 44, 705. – [11b] V. Nair,
D. W. Powell, S. C. Suri, Synth. Commun. 1987, 17, 1897. – [11c]
S. C. Suri, V. Nair, Synthesis 1990, 695.
S. Torii, H. Tanaka, T. Sirui, M. Akada, J. Org. Chem. 1979,
44, 3305.
In this laboratory, P. Gizecki prepared the diaryl 8 in 32% yield
by a mixed Ullmann reaction (activated Cu powder/220° C/2 h)
between 1-iodo-2,3,4-trimethoxybenzene and 3-iodo-4-me-
thoxy-benzaldehyde.
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E. Fujita, K. Fuji, K. Tanaka, J. Chem. Soc.(C) 1971,
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V. Karpunin, Zh. Prikl. Khim. (Leningrad) 1978, 51, 2387;
Chem. Abst. 1979, 90, 138346 g.
[21]
[22]
[12]
[13]
[23] [23a]
J. A. Marshall, J. C. Peterson, L. Lebioda, J. Am. Chem.
[23b]
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Received June 23, 1999
[O99383]
N. L. Allinger, M. Nakazaki, V.
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S. A. DiBiase, B. A. Lipisko, A. Haag, R. A. Wolak, G. W.
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Eur. J. Org. Chem. 2000, 1527Ϫ1533
1533