Studies on tellurium-containing heterocycles. Part 22. Tellurazepine ring system: Preparation of 1,5-benzotellurazepin-4-ones and their conversion into fully unsaturated 1,5-benzotellurazepines

Article abstract of DOI:10.1248/cpb.52.413

The treatment of o-iodopropiolanilides (12), which were easily prepared from o-iodophenylisocyanate (11) and ethynylmagnesium bromide, with sodium hydrogen telluride resulted in the intramolecular ring closure of the presumed phenyltellurol intermediates (13) to a triple bond to give the 1,5-benzotellurazepin-4-ones (14) as the sole characterized products. The obtained amides (14) were easily converted into fully unsaturated lactim 4-methoxy-1,5-benzotellurazepines (18) by treatment with trimethyloxonium tetrafluoroborate. Decomposition by thermolysis of the 4-methoxyazepinenes (18) afforded the 4-methoxyquinolines (19) with extrusion of a tellurium atom.

Full text of DOI:10.1248/cpb.52.413

April 2004
Chem. Pharm. Bull. 52(4) 413—417 (2004)
413
Studies on Tellurium-Containing Heterocycles. Part 22.1) Tellurazepine
Ring System: Preparation of 1,5-Benzotellurazepin-4-ones and Their
Conversion into Fully Unsaturated 1,5-Benzotellurazepines
Haruki SASHIDA* and Hirohito SATOH
Faculty of Pharmaceutical Sciences, Hokuriku University; Kanagawa-machi, Kanazawa 920–1181, Japan.
Received November 6, 2003; accepted December 20, 2003
The treatment of o-iodopropiolanilides (12), which were easily prepared from o-iodophenylisocyanate (11)
and ethynylmagnesium bromide, with sodium hydrogen telluride resulted in the intramolecular ring closure of
the presumed phenyltellurol intermediates (13) to a triple bond to give the 1,5-benzotellurazepin-4-ones (14) as
the sole characterized products. The obtained amides (14) were easily converted into fully unsaturated lactim 4-
methoxy-1,5-benzotellurazepines (18) by treatment with trimethyloxonium tetrafluoroborate. Decomposition by
thermolysis of the 4-methoxyazepinenes (18) afforded the 4-methoxyquinolines (19) with extrusion of a tellurium
atom.
Key words 1,5-benzotellurazepin-4-one; 1,5-benzotellurazepine; intramolecular cyclization; phenyltellurol; triple bond
mada24) in almost quantitative yield. The successful reaction
of the isocyanate (11) with Grignard reagents was a result of
the sp2–sp carbon–carbon bond formation to afford the o-
iodopropiolanilides (12), the key starting compounds for the
synthesis of the tellurazepinones (14). Compound 11 reacted
with one equivalent of an alkynylmagnesium bromide in
tetrahydrofuran (THF) at 0 °C to give the corresponding
anilides (12) as the sole product in moderate to good yields.
The telluration of the o-iodopropiolanilides (12) via the
lithium compound, which was the method for the preparation
of the 1-benzotellurepines, was unsuccessful. Therefore, we
examined our original telluration method for the construction
The chemistry of the thiazepine ring systems, seven-mem-
bered heterocycles containing atoms of both sulfur and nitro-
gen has been reviewed.2—6) Monocyclic 1,4-thiazepine com-
pounds (1, 2) have been prepared by the Schmidt ring-expan-
sion of 4H-thiopyran-1,1-dioxides7) and by the Beckmann re-
arrangement of thiapyran-4-one oxime.8) The syntheses of its
benzo derivatives, the 1,5-benzothiazepines (3), were de-
scribed by Hofmann and Fischer9,10) and by Kaupp et al.11)
The procedure for the preparation of these compounds is the
cis-addition of o-mercaptoaniline to propiolic acid, followed
by the cyclization of the adducts. 1,4-Benzothiazepines (4)12)
have also been produced by the condensation of 2-mercapto-
benzamide and bromoacetaldehyde diethylacetal. Further-
more, the photocycloaddition of 2-phenylbenzothiazole
with acetylenes gave the 1,5-benzothiazepines (5)13) in one
step. In addition, a number of tellurium-nitrogen-containing
heterocycles14) have been prepared. However, only two pa-
pers15,16) have been published to date on the synthesis of
seven-membered tellurazepine rings. 1,4-Dibenzo[b,f]tellu-
razepine (7)15) was prepared by the thermolysis of 9-azido-
xanthene (6) in 1987. The one-pot synthesis of the 2-aryl-
1,5-benzotellurazepines (9)16) has been reported based on the
condensation of sodium 2-aminophenyltellurolate (8) with
arylpropargyl aldehydes.
In recent years, we have been investigating the syntheses
of the 3-benzotellurepines17) and 1-benzotellurepines,18,19)
novel fully unsaturated seven-membered heterocycles con-
taining a tellurium atom. More recently, a convenient syn-
thetic route for the preparation of tellurochromones,20) six-
membered tellurium-containing carbonyl compounds, was
also reported. Our synthetic strategy21,22) for the preparation
of these compounds is based on the intramolecular cycliza-
tion of the tellurol moieties to a triple bond. In this respect,
we report herein the synthesis of the title compounds23) as
an extension of increasing interest in our methodology for
preparing the tellurium-containing heterocycles.
Chart 1
The first sub-goal is the preparation of the tellurazepinones
(14). The preparation of 14 from o-iodobenzoic acid (10) is
shown in Chart 3. o-Iodophenylisocyanate (11) was easily
prepared from 10 via one-step according to the diphenylphos-
pholic azide (DPPA) procedure reported by Shioiri and Ya-
Chart 2
© 2004 Pharmaceutical Society of Japan
To whom correspondence should be addressed. e-mail: h-sashida@hokuriku-u.ac.jp

414
Vol. 52, No. 4
Chart 3
Table 1. 1,5-Benzotellurazepin-4-ones (14)
razepines (14), and their corresponding oxidized ditellurides
were not produced. If the first step of the reaction is the
Michael-type addition of NaHTe to the ynone function of 12,
the adducts (16, 17) should be generated in the same ratio. In
addition,23) the reaction of the propiolanilide having no halo-
gen group at the ortho position with NaHTe under the same
reaction conditions used for the preparation of 14 did not af-
ford any adducts or the corresponding ditellurides. It is re-
ported25) that an electron-withdrawing group at the resonance
position on an aromatic ring could significantly enhance the
reactivity of the nucleophilic substitution of the iodo anion
with the hydrotelluro group, however, an electron-donating
group decreased; e.g., p-aminoiodobenzene did not react
with NaHTe to give the p-aminophenyl tellurol or the corre-
sponding ditelluride. The starting material was recovered.
For the reaction of the propiolanilides (12) with NaHTe, the
Conpound
Appearance
(mp °C)
R
Yield (%)
No.
14a
14b
14c
14
Me
n-Bu
tert-Bu
n-Hex
Ph
19
26
Pale yellow prisms
(118—120)
Pale yellow prisms
(148—150)
Pale yellow prisms
(150—151)
Yellow prisms
(172—174)
Pale yellow prisms
(184—186)
Pale yellow prisms
(96—98)
29
25
14e
14f
26
TMS
Trace
of the 1,5-benzotellurazepine skeleton, and applied the one- replacement of the iodo anion by the hydrotelluro group
pot method for the preparation of the tellurochromones20) would proceed because of the decreased electron-donating
from the o-bromophenylethynyl ketones described in our pre- inductive effect due to the change in the amino group to the
vious paper. The treatment of the propiolanilides (12) with amide such as a propiolalnilide.
sodium hydrogen telluride (NaHTe),25) generated in situ from
In order to introduce the conjugated double bond, the lac-
tellurium powder and sodium borohydride in dimethylform- tams (14b—e) were treated with trimethyloxonium tetrafluo-
amide (DMF) at ca. 100 °C, resulted in the direct ring clo- roborate (Me3Oϩ BF4Ϫ) in dichloromethane at 0 °C to give the
sure to afford the desired 1,5-benzotellurazepin-4-ones (14) 4-methoxy-1,5-benzotellurazepines (18b—e) in ca. 40—45%
as the sole characterized product. The results of this ring clo- yields. 2-Methyltellurazepine (18a) was essentially formed
sure for the preparation of 14 are shown in Table 1. 2-Alkyl- and detected on TLC, however, it could not be isolated. 18a
(14a—d), 2-phenyl- (14e) and 2-trimethylsilyl (TMS)-tellu- was decomposed during the normal isolating operation be-
razepinones (14f) were obtained as stable yellow crystalline cause of its thermal instability. Compounds (18b—e) are
products with an unknown complex mixture, while the yields somewhat unstable, and gradually decomposed during stor-
of the expected tellurazepines (14) were not good. Especially, age at room temperature even under argon. It is well known
the TMS derivative (14f) was isolated in only a trace amount, that simple monocyclic thiepines, selenepines and benzotel-
probably because of the thermal instability of 14 itself and its lurepines13) are thermally unstable due to the easy extrusion
desylilated parent product, which might be produced under of the hetero elements, but the stability of the heteropine ring
such conditions. The obtained tellurazepinones (14) are novel can be enhanced by the introduction of a bulky group into
compounds, and were characterized on the basis of the spec- the a-position. We next examined a few reactions of the new
tral data (Table 2). Neither the presumable phenyltellurole in- 1,5-benzotellurazapinene rings using 14 and 18 for compari-
termediates (13) nor their oxidized dimeric-type products, son with the 1-benzotellerepines,13) whose reactivity was de-
the ditellurides, were obtained. The tellurazepinones (14) scribed in our previous report. However, the halogenation
were produced by the Michael-type 7-endo-dig ring closure with SO2Cl2, Br2 or I2 and the oxidation of the tellurazepines
of the tellurols (13) at the sp carbon atom of the triple bond; (14, 18) gave a complex mixture without any characterized
the 6-exo-dig reaction products (15) were not formed.
products. The reactions of 14 and 18 with lithium reagents or
An alternative mechanism for the formation of 14 would Grignard reagents also afforded no characterized products.
involve the addition of NaHTe to an alkynyl moiety to first The pyrolysis of 18 at 160 °C in mesitylene for ca. 1 h re-
produce the Z-vinyltellurols (16). However, this possibility sulted in the exclusion of the Te element to yield the 2-
was eliminated by the facts that the regio isomers, E-vinyltel- methoxyquinolines (19b—d) in good yields. Upon heating
lurols (17), which might not cyclize to form the tellu- under these conditions, the 2-phenyltellurazepinone (18e) af-

April 2004
415
Table 2. Spectral Data for the 1,5-Benzotellurazepin-4-ones (14)
Formula
1H-NMR (500 MHz, JϭHz)
IR
Compound No.
R
cmϪ1
MS (m/z: Mϩ)
3-H
NH
Ph–H
R–H
14a
RϭMe
C10H9NOTe
(289)
3176 (NH)
1646 (CϭO)
6.54
(q, Jϭ1.8)
9.39
(br s)
7.07 (1H, dd, Jϭ7.3, 7.8)
7.26 (1H, Jϭ7.8)
2.48 (3H, d, Jϭ1.8)
Me
7.35 (1H, dd, Jϭ7.3, 7.8)
7.80 (1H, d, Jϭ7.8)
14b
Rϭn-Bu
C13H15NOTe
(331)
3150 (NH)
1654 (CϭO)
6.55
(s)
9.39
(br s)
7.06 (1H, dd, Jϭ7.3, 7.8)
7.26 (1H, d, Jϭ7.8)
7.34 (1H, dd, Jϭ7.3, 7.8)
7.80 (1H, d, Jϭ7.8)
0.89 (3H, t, Jϭ7.3)
1.26—1.33 (2H, m)
1.47—1.51 (2H, m)
2.60 (2H, t, Jϭ7.3)
n-Bu
14c
Rϭtert-Bu
C13H15NOTe
(331)
3176 (NH)
1652 (CϭO)
6.58
(s)
8.09
(br s)
7.05 (1H, dd, Jϭ7.3, 7.8)
7.16 (1H, d, Jϭ7.8)
1.18 (9H, s)
tert-Bu
7.36 (1H, dd, Jϭ7.3, 7.8)
7.87 (1H, d, Jϭ7.8)
14d
Rϭn-Hex
C15H19NOTe
(359)
3162 (NH)
1627 (CϭO)
6.54
(s)
9.03
(br s)
7.06 (1H, dd, Jϭ7.3, 7.8)
7.24 (1H, d, Jϭ7.8)
7.35 (1H, dd, Jϭ7.3, 7.8)
7.80 (1H, d, Jϭ7.8)
0.86 (3H, t, Jϭ7.3)
1.25—1.29 (6H, m)
1.48—1.52 (2H, m)
2.59 (2H, Jϭ7.3)
n-Hex
14e
RϭPh
C15H11NOTe
(351)
3460 (NH)
1646 (CϭO)
7.52
(s)
8.56
(br s)
6.93 (1H, dd, Jϭ7.3, 7.5), 6.97 (1H, d, Jϭ7.5), 7.18 (1H,
dd, Jϭ7.3, 7.3), 7.28—7.32 (2H, m), 7.37 (1H, d,
Jϭ7.5), 7.39—7.7.43 (1H, m), 7.45—7.49 (2H, m)
Ph
14f
RϭTMS
C12H15NOSiTe
(347)
3192 (NH)
1650 (CϭO)
8.15
(s)
8.2
(br)
6.81 (1H, d, Jϭ8.0)
0.24 (9H, s)
TMS
6.94 (1H, dd, Jϭ7.7, 7.7)
7.18 (1H, dd, Jϭ8.0, 7.7)
7.44 (1H, d, Jϭ7.7)
2 h, and then washed with water (300 mlϫ3), brine and dried (MgSO4). The
benzene solution was heated to refluxing temperature for 1—2 h, and evapo-
rated in vacuo to give crude isocyanate (11) as a pale yellow oil in almost
quantitative yield.
IR (neat) cmϪ1: 2260 (NϭCϭO). 11 was immediately used for the next
step without purification.
Preparation of o-Iodopropiolanilides (12) The above benzene solution
(300 ml) of o-iodophenylisocyanate (11, 0.3 mol) was added to a THF
(200 ml) solution of an alkynylmagnesium bromide (0.3 mol), which was
freshly prepared from ethylmagnesium bromide (0.3 mol) and the corre-
sponding 1-alkyne (0.3 mol) under an argon atmosphere at 0 °C. The reac-
tion mixture was stirred overnight at room temperature, and quenched by ad-
dition of 20% ammonium chloride solution (300 ml). After separation of or-
ganic layers, the aqueous layer was extracted with benzene (100 mlϫ3). The
combined organic fraction was washed with 3% H2SO4 (150 mlϫ2), satd.
NaHCO3 (100 mlϫ2) and brine (150 mlϫ2), and dried (MgSO4). Evapora-
tion of organic solvent in vacuo gave the crude product (12), which was re-
Chart 4
forded no isolable products, and gradually decomposed. The
tellurazepinones (14) were quite stable without decomposi-
tion in refluxing mesitylene.
In conclusion, the construction of the 1,5-benzotellu-
razepine ring system was achieved using the intramolecular
cyclization of the tellurol to a triple bond. The obtained novel crystallized from acetone–n-hexane to afford the pure anilides.
12a (RϭMe): 48.13 g, 56% yield, pale yellow leaflets, mp 144—146 °C.
tellurazepinones were transformed into the fully unsaturated
4-methoxy-1,5-benzotellurazepines, which were decomposed
to afford the quinoline derivatives with their ready tellurium
extrusion. Neither the selenium and sulfur seven-membered
analogues could be obtained using similar methods.
IR (KBr) cmϪ1: 3264 (NH), 2240 (CϵC), 1640 (CϭO). 1H-NMR (90 MHz,
CDCl3) d: 2.27 (3H, s, Me), 7.12, 7.62, 8.07 and 8.43 (1H, ddd, Jϭ8, 8,
2 Hz, 1H, ddd, Jϭ8, 8, 2 Hz, 1H, dd, Jϭ8, 2 Hz, and 1H, br d, Jϭ8 Hz,
Ph–H), 8.0 (1H, br, NH). MS m/z: 285 (Mϩ, 30), 219 (25), 158 (100), 67
(78). Anal. Calcd for C10H8NOI: C, 42.11; H, 2.83; N, 4.91. Found: C,
41.93; H, 2.63; N, 4.90.
12b (Rϭn-Bu): 58.90 g, 60% yield, colorless leaflets, mp 77—80 °C. IR
(KBr) cmϪ1: 3272 (NH), 2236 (CϵC), 1642 (CϭO). 1H-NMR (90 MHz,
CDCl3) d: 0.85, 1.1—1.7 and 2.28 (3H, t, Jϭ6 Hz, 4H, m, 2H, t, Jϭ6 Hz, n-
Bu), 6.82, 7.32, 7.77 and 8.17 (1H, ddd, Jϭ8, 8, 2 Hz, 1H, ddd, Jϭ8, 8,
2 Hz, 1H, dd, Jϭ8, 2 Hz, and 1H, br d, Jϭ8 Hz, Ph–H), 7.7 (1H, br, NH). MS
m/z: 327 (Mϩ, 22), 219 (16), 200 (100), 109 (20). Anal. Calcd for
C13H14NOI: C, 47.73; H, 4.31; N, 4.28. Found: C, 47.52; H, 4.05; N, 4.28.
12c (Rϭtert-Bu): 61.8 g, 63% yield, colorless leaflets, mp 65—67 °C. IR
(KBr) cmϪ1: 3262 (NH), 2228 (CϵC), 1658 (CϭO). 1H-NMR (90 MHz,
CDCl3) d: 1.30 (9H, s, tert-Bu), 6.88, 7.40, 7.83 and 8.20 (1H, ddd, Jϭ8, 8,
2 Hz, 1H, ddd, Jϭ8, 8, 2 Hz, 1H, dd, Jϭ8, 2 Hz, and 1H, br d, Jϭ8 Hz,
Ph–H), 7.7 (1H, br, NH). MS m/z: 327 (Mϩ, 21), 200 (100), 109 (33), 81
(43). Anal. Calcd for C13H14NOI: C, 47.73; H, 4.31; N, 4.28. Found: C,
47.49; H, 4.07; N, 4.26.
Experimental
Melting points were measured on a Yanagimoto micro melting point hot
stage apparatus and are uncorrected. IR spectra were determined with a Hi-
tachi 270-30 spectrometer. Mass spectra (MS) and HR-MS were recorded on
1
a JEOL JMS-DX300 instrument. H-NMR spectra were determined with a
JEOL PMX-60SI (60 MHz), a JEOL EX-90A (90 MHz) or a JEOL ECP-500
(500 MHz) spectrometer in CDCl3 using tetramethylsilane as internal stan-
dard; J values are given in Hz. 13C-NMR spectra were recorded on a JEOL
ECP-500 (125 MHz) spectrometer. Microanalyses were performed in the
Microanalytical Laboratory of this Faculty.
Preparation of o-Iodophenylisocyanate (11) DPPA (82.6 g, 0.3 mol)
was added to a mixture of o-iodobenzoic acid (10, 74.4 g, 0.3 mol) and tri-
ethylamine (30.3 g, 0.3 mol) in benzene (300 ml) at 0 °C under an argon at-
mosphere. The reaction mixture was stirred under the same conditions for

416
Vol. 52, No. 4
12d (Rϭn-Hex): 78.54 g, 74% yield, pale yellow leaflets, mp 55—57 °C. CDCl3) d: 0.85, 1.1—1.6 and 2.54 (3H, t, Jϭ7 Hz, 8H, m, 2H, t, Jϭ7 Hz, n-
IR (KBr) cmϪ1: 3272 (NH), 2232 (CϵC), 1640 (CϭO). 1H-NMR (90 MHz, Hex), 3.85 (3H, s, OMe), 6.37 (1H, s, 3-H), 6.9—7.3 and 7.68 (3H, m, 1H,
CDCl3) d: 0.90, 1.0—2.0 and 2.33 (3H, t, Jϭ5 Hz, 8H, m, and 2H, t, d, Jϭ7 Hz, Ph–H). MS m/z: 373 (Mϩ, 30), 371 (28), 243 (55), 242 (100),
Jϭ6 Hz, n-Hex). 6.83, 7.33, 7.77 and 8.20 (1H, ddd, Jϭ8, 8, 2 Hz, 1H, ddd, 214 (25), 173 (50), 373.0711 (Calcd for C16H21NOTe: 373.0685).
Jϭ8, 8, 2 Hz, 1H, dd, Jϭ8, 2 Hz, and 1H, br d, Jϭ8 Hz, Ph–H), 7.9—8.5
18d (RϭPh): 28 mg, 39% yield, colorless oil. 1H-NMR (90 MHz, CDCl3)
(1H, br, NH). MS m/z: 355 (Mϩ, 28), 228 (100), 219 (20). Anal. Calcd for d: 3.97 (3H, s, OMe), 6.50 (1H, s, 3-H), 7.1—7.8 (9H, m, Ph–H). MS m/z:
C15H18NOI: C, 50.71; H, 5.11; N, 3.94. Found: C, 50.55; H, 5.12; N, 3.89.
12e (RϭPh): 66.6 g, 64% yield, yellow prisms, mp 103—104 °C. IR
(KBr) cmϪ1: 3148 (NH), 2212 (CϵC), 1630 (CϭO). 1H-NMR (90 MHz,
CDCl3) d: 6.88, 7.2—7.6, 7.83 and 8.30 (1H, ddd, Jϭ8, 8, 2 Hz, 6H, m, 1H,
dd, Jϭ8, 2 Hz, and 1H, br d, Jϭ8 Hz, Ph–H), 8.0 (1H, br, NH). MS m/z: 347
365 (Mϩ, 85), 363 (80), 235 (100), 234 (46), 365.065 (Calcd for
C16H13NOTe: 365.059).
Thermolysis of Tellurazepine (18): Formation of 2-Methoxyquinoline
(19) A solution of tellurazepine (18, 0.04 mol) in mesitylene (3 ml) was re-
fluxed for 1 h. After cooling, the mixture was chromatographed on silica gel
(Mϩ, 18), 220 (99), 129 (100). Anal. Calcd for C15H10NOI: C, 51.89; H, using CH2Cl2 as an eluent to give the 2-methoxyquinolines (19).
2.90; N, 4.03. Found: C, 51.80; H, 2.99; N, 4.00.
4-n-Butyl-2-methoxyquinoline (19b): 6.3 mg, 73% yield, colorless oil.
12f (RϭTMS): 47.3 g, 46% yield, colorless needles, mp 82—84 °C. IR 1H-NMR (90 MHz, CDCl3) d: 0.97, 1.3—2.0 and 2.99 (3H, t, Jϭ6 Hz, 4H,
(KBr) cmϪ1: 3296 (NH), 2212 (CϵC), 1642 (CϭO). 1H-NMR (90 MHz, m, 2H, t, Jϭ8 Hz, n-Bu), 4.06 (3H, s, OMe), 6.75 (1H, s, 3-H), 7.4—8.0
CDCl3) d: 0.33 (9H, s, TMS), 6.88, 7.37, 7.83 and 8.20 (1H, ddd, Jϭ8, 8, (4H, m, Ph–H). MS m/z: 215 (Mϩ, 100), 214 (98), 186 (48), 185 (35), 173
2 Hz, 1H, ddd, Jϭ8, 8, 2 Hz, 1H, dd, Jϭ8, 2 Hz, and 1H, br d, Jϭ8 Hz, (55), 215.1313 (Calcd for C14H17NO: 215.1310).
Ph–H), 7.9 (1H, br, NH). MS m/z: 343 (Mϩ, 20), 216 (100), 125 (22), 97
(19). Anal. Calcd for C12H14NOISi: C, 41.98; H, 4.11; N, 4.08. Found: C,
42.10; H, 4.02; N, 4.10.
4-tert-Butyl-2-methoxyquinoline (19c): 7.5 mg, 87% yield, colorless oil.
1H-NMR (90 MHz, CDCl3) d: 1.58 (9H, s, tert-Bu), 4.05 (3H, s, OMe), 6.87
(1H, s, 3-H), 7.3—7.6, 7.89 and 8.29 (2H, m, 1H, d, Jϭ8 Hz and 1H, d,
Preparation of 1,5-Benzotellurazepin-4-ones (14) Under an argon at- Jϭ8 Hz, Ph–H). MS m/z: 215 (Mϩ, 100), 214 (98), 200 (51), 186 (40), 185
mosphere, a solution of o-iodopropiolanilides (12, 20 mmol) in DMF (20 ml) (40), 215.1318 (Calcd for C14H17NO: 215.1310).
was slowly added to a solution of sodium hydrogen telluride (24 mmol),
4-n-Hexyl-2-methoxyquinoline (19d): 6.5 mg, 67% yield, colorless oil.
which was prepared from tellurium powder (3.06 g, 24 mmol) and sodium 1H-NMR (90 MHz, CDCl3) d: 0.94, 1.1—2.5 (3H, t, Jϭ7 Hz, 10H, m, n-
borohydride (1.08 g, 24 mmol) in DMF (80 ml), at 100 °C for 2 h. The whole Hex), 3.84 (3H, s, OMe), 6.57 (1H, s, 3-H), 6.8—6.9, 7.5—7.6 and 7.9—8.0
reaction mixture was stirred under these conditions overnight and poured (2H, m, 1H, m, 1H, m, Ph–H). MS m/z: 243 (Mϩ, 100), 242 (98), 214 (29),
into cold water (500 ml). The aqueous mixture was filtered and extracted 173 (49), 243.1603 (Calcd for C16H21NO: 243.1623).
with benzene (200 mlϫ3). The extracts were washed with water (100 mlϫ3),
brine (50 mlϫ2) and dried (MgSO4), and then concentrated. The resulting
Acknowledgements A part of his work was supported by a Grant-in-
residue was chromatographed on silica gel, eluting with CH2Cl2–acetone, to Aid for Scientific Research from The Ministry of Education, Culture,
give 14. Products were recrystallized from n-hexane–acetone. The results Sports, Science and Technology of Japan, and The Specific Research Fund
are given in Table1, HR-MS, IR and 1H-NMR spectral data for 14 are listed of Hokuriku University. The authors wish to express appreciation to Mr.
in Table 2.
K. Tashiro and Miss H. Kubo for their technical support and to Mr. M.
14a (RϭMe): HR-MS m/z: 288.9850 (Calcd for C10H9NOTe: 288.9746). Teranishi for the 13C-NMR measurement.
13C-NMR (CDCl3) d: 32.77 (q), 113.39 (s), 123.91 (d), 126.42 (d), 130.15
(d), 132.07 (s), 132.41 (d), 138.89 (d), 141.04 (s), 170.77 (s).
References and Notes
14b (Rϭn-Bu): Anal. Calcd for C13H15NOTe: C, 47.48; H, 4.60; N, 4.26.
Found: C, 47.49; H, 4.54; N, 4.25. 13C-NMR (CDCl3) d: 13.83 (q), 21.88 (t),
31.31 (t), 44.85 (t), 113.11 (s), 123.75 (d), 126.37 (d), 130.10 (d), 131.07
(d), 138.95 (d), 139.41 (s), 141.27 (s), 170.82 (s).
14c (Rϭtert-Bu): Anal. Calcd for C13H15NOTe: C, 47.48; H, 4.60; N,
4.26. Found: C, 47.68; H, 4.64; N, 4.12. 13C-NMR (CDCl3) d: 29.45 (q),
40.63 (s), 113.69 (s), 123.06 (d), 128.01 (d), 129.19 (d), 130.10 (d), 139.34
(d), 141.38 (s), 151.74 (s), 170.59 (s).
14d (Rϭn-Hex): Anal. Calcd for C15H19NOTe: C, 50.48; H, 5.37; N, 3.92.
Found: C, 50.43; H, 5.27; N, 3.95. 13C-NMR (CDCl3) d: 13.99 (q), 22.44 (t),
28.37 (t), 29.13 (t), 31.49 (t), 45.13 (t), 113.22 (s), 123.69 (d), 126.40 (d),
130.07 (d), 131.02 (d), 138.98 (d), 139.59 (s), 141.18 (s), 170.62 (s).
14e (RϭPh): HR-MS m/z: 350.9908 (Calcd for C15H11NOTe: 350.9903).
13C-NMR (CDCl3) d: 118.23 (s), 123.00 (d), 124.06 (d), 124.00 (d), 127.98
(d), 128.28 (d), 128.99 (d), 129.00 (d), 132.75 (d), 137.39 (s), 139.07 (s),
144.70 (s), 163.33 (s).
1) For Part 21, see: Sashida H., Satoh H., Ohyanagi K., Heterocycles, 61,
309—317 (2004).
2) Chimirri A., Gitto R., Grasso S., Monforte A. M., Zappala M., “Ad-
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Contraction of Heterocycles by Sulfur Extrusion,” Vol. 65, ed.by Ka-
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4) Wunsch K.-H., Ehlers A., Z. Chem., 10, 361—370 (1970).
5) Murata I., Phosphorus Sulfur and Silica, 43, 243—259 (1989).
6) Levai A., J. Heterocyclic Chem., 37, 199—214 (2000).
7) Ried W., Bopp H., Synthesis, 1978, 211—212 (1978).
8) Yamamoto K., Yamazaki S., Osedo H., Murata I., Angew. Chem. Int.
Ed. Engl., 7, 635—637 (1986).
9) Hofmann H., Fischer H., Z. Naturforsch., 42b, 217—220 (1987).
14f (RϭTMS): HR-MS m/z: 346.9999 (Calcd for C12H15NOSiTe: 10) Hofmann H., Fischer H., Bremer M., Chem. Ber., 120, 2087—2089
346.9985). (1987).
Treatment of 14 with Me3O؉ BF4؊: Formation of 4-Methoxy-1,5-ben- 11) Kaupp G., Gründken E., Matthies D., Chem. Ber., 119, 3109—3120
zotellurazepines (18) To a solution of the lactam (14, 0.2 mmol) in
(1986).
CH2Cl2 (10 ml) was added Me3Oϩ BF4Ϫ (88 mg, 0.6 mmol) at 0 °C under an 12) Hofmann H., Fischer H., Chem. Ber., 121, 2147—2150 (1988).
argon atmosphere. The reaction mixture was stirred at room temperature 13) Sindler-Kulyk M., Neckers D. C., J. Org. Chem., 47, 4914—4919
overnight, and then quenched with 10% K2CO3 solution. The mixture was
(1982).
extracted with CH2Cl2 and washed with brine (50 mlϫ2) and the extracts 14) Sadekov I. G., Minkin V. I., “Advances in Heterocyclic Chemistry, Tel-
were dried (MgSO4). The solvent was removed in vacuo and the resulting
residue was chromatographed on silica gel using n-hexane–CH2Cl2 (1 : 2) as
an eluent to give 18.
lurium-Nitrogen-Containing Heterocycles,” Vol. 79, ed. by Katritzky
A. R., Academic Press, London, 2001, pp. 1—36.
15) Ladatko A. A., Sadekov I. D., Minkin V. I., Khim. Geterotsikl. Soedin.,
2, 279 (1987).
18b (Rϭn-Bu): 28 mg, 41% yield, colorless oil. 1H-NMR (90 MHz,
CDCl3) d: 0.87, 1.2—1.5 and 2.55 (3H, t, Jϭ6 Hz, 4H, m, 2H, t, Jϭ7 Hz, n- 16) Garnovskii A. D., Sadekov I. D., Antsishkina A. S., Sadikov G. G.,
Bu), 3.85 (3H, s, OMe), 6.37 (1H, s, 3-H), 6.9—7.3 and 7.68 (3H, m and
1H, d, Jϭ7 Hz, Ph–H). MS m/z: 345 (Mϩ, 40), 343 (35), 215 (80), 214
(100), 345.0375 (Calcd for C14H17NOTe: 345.0372).
Borodkin G. S., Uraev, A. I., Maksimenko A. A., Vasilchenko I. S.,
Borodkina I. G., Sergienko V. S., Minkin V. I., Koord. Khim., 25, 821
(1999). This literature is cited in ref. 14 (p. 24), but we were unable to
find it.
18c (Rϭtert-Bu): 31 mg, 45% yield, colorless oil. 1H-NMR (90 MHz,
CDCl3) d: 1.16 (9H, s, tert-Bu), 3.89 (3H, s, OMe), 6.40 (1H, s, 3-H), 6.8— 17) Sashida H., Kurahashi H., Tsuchiya T., J. Chem. Soc. Chem. Commun.,
7.4 and 7.75 (3H, m, 1H, d, Jϭ7 Hz, Ph–H). MS m/z: 345 (Mϩ, 40), 343
1991, 802 (1991).
(35), 215 (75), 214 (100), 200 (34), 186 (27), 345.0285 (Calcd for 18) Sashida H., Ito K., Tsuchiya T., J. Chem. Soc. Chem. Commun., 1993,
C14H17NOTe: 345.0372). 1493—1493 (1993).
18d (Rϭn-Hex): 29 mg, 40% yield, colorless oil. 1H-NMR (90 MHz, 19) Sashida H., Ito K., Tsuchiya T., Chem. Pharm. Bull., 43, 19—25

April 2004
(1995).
417
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