Synthesis of isochalcogenazole rings by treating β-(N,N- dimethylcarbamoylchalcogenenyl)alkenyl ketones with hydroxylamine-O-sulfonic acid

Article abstract of DOI:10.1246/bcsj.80.567

β-(N,N-Dimethylcarbamoylselenenyl)- and β-(N,N- dimethylcarbamoyltellurenyl)alkenyl ketones were converted into isoselenazoles and isotellurazole Te-oxides, respectively, simply by treating with hydroxylamine-O-sulfonic acid, and deoxygenation of the latt

Full text of DOI:10.1246/bcsj.80.567

Ó 2007 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 80, No. 3, 567–577 (2007)
567
Synthesis of Isochalcogenazole Rings by Treating
ꢀ-(N,N-Dimethylcarbamoylchalcogenenyl)alkenyl
Ketones with Hydroxylamine-O-sulfonic Acid
ꢀ1
Kazuaki Shimada, Akiko Moro-oka,1 Akiko Maruyama,1 Hiroyuki Fujisawa,1
Toshio Saito,1 Ryo Kawamura,1 Hisashi Kogawa,1 Maiko Sakuraba,1
Yukichi Takata,1 Shigenobu Aoyagi,1 Yuji Takikawa,1 and Chizuko Kabuto2
1Department of Chemical Engineering, Faculty of Engineering, Iwate University, Morioka 020-8551
2Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University,
Aramaki, Aoba-ku, Sendai 980-8578
Received August 3, 2006; E-mail: shimada@iwate-u.ac.jp
ꢀ-(N,N-Dimethylcarbamoylselenenyl)- and ꢀ-(N,N-dimethylcarbamoyltellurenyl)alkenyl ketones were converted
into isoselenazoles and isotellurazole Te-oxides, respectively, simply by treating with hydroxylamine-O-sulfonic acid,
and deoxygenation of the latter products was successfully carried out by treating with PPh3. Alternative treatment of
ynone oxime tosylates with hydrochalcogenide ions or N,N-dimethylchalcogenocarbamate ions also gave the same iso-
chalcogenazole rings. These reactions were assumed to proceed through intramolecular nucleophilic substitution on the
nitrogen atom of oxime sulfonates by the attack of in situ generated chalcogen nucleophiles.
Recently, hetero Diels–Alder reactions have become one of
the most effective methods for the syntheses of various hetero-
cycles, and especially, the thermal reactions of cyclic hetero-
dienes possessing removable heteroatom-bridges, such as O,
S, SO2, and N=N atoms, have been widely used as preparable
and treatable heterodynes with a cisoid structure.1–5 Especial-
ly, chalcogen-containing five-membered heterocycles have
been regarded as novel bridged heterodienes, and the synthetic
use of these compounds have been extensively studied in the
light of their potentiality of novel 4ꢁ components for hetero
Diels–Alder reactions. However, the synthetic pathways to
construct complicated compounds have been limited because
of the thermal stability of the oxygen-, sulfur-, or nitrogen-
bridged compounds, and less reactive isothiazole S,S-dioxides
as potential SO2-bridged heterodienes for hetero Diels–Alder
reactions have also been reported.6–9 It has been assumed that
selenium or tellurium analogues of such substrates would be
more reactive because of the weak C-chalcogen or N-chalco-
gen bonds and the enhanced ring strain of these five-membered
heterocylces along with a decrease in aromaticity.10,11 More-
over, subsequent heteroatom extrusion from these compounds
should also be possible under much milder reaction conditions
than those of the oxygen or sulfur derivatives.12,13
However, to date, only limited methods for the preparation
of isoselenazoles and isotellurazoles have been reported15–27
in spite of their potential as acceptors for nucleophiles,17,28
electrophiles,29 and reactive heterodienes, and thus, new and
efficient synthetic methods for these compounds are required.
Actually, we have already reported a convenient preparation of
Se-alkenyl selenocarbamates 4 and Te-alkenyl tellurocarba-
mates 5 involving a stepwise reduction–alkylation reaction
starting from bis(N,N-dimethylcarbamoyl) dichalcogenides 1
and 2,30–32 and the Lewis acid-induced removal of dimethyl-
carbamoyl group from 4 (X ¼ Se) and 5 (X ¼ Te) forming di-
alkenyl diselenides and ditellurides, respectively. These results
suggested that in situ generated Z-alkenechalcogenol deriva-
tives A bearing a leaving group on the oxime nitrogen atom
would undergo facile ring closure to give isochalcogenazoles
6 and 7 via intramolecular nucleophilic substitution on the ni-
trogen atom. Here, we describe a new and convenient synthetic
route for isoselenazole and isotellurazole ring systems start-
ing from chalcogenocarbamates 4 (X ¼ Se) or 5 (X ¼ Te),
hydroxylamine-O-sulfonic acid, and ynones 3 as shown in
Scheme 1. Alternative attempts to prepare 6 and 7 from ynone
oxime tosylates 12 and chalcogen nucleophiles are also men-
tioned in this paper.
In the course of our studies on the syntheses and chemical
conversion of heavy chalcogen-containing heterocyclic com-
pounds, we have preliminarily reported the thermal reaction
of 1,2,4-selenadiazoles, a 1,2,5-selenadiazole, and a 1,3-selena-
zoles in the presence of acetylenic dienophiles to afford the
corresponding nitrogen-containing six-membered heterocycles
in high yields via hetero Diels–Alder reactions and the subse-
quent selenium extrusion.14 Extension of the synthetic methods
to heavy isochalcogenazoles became a challenging target.
Results and Discussion
Preparation of Se-Alkenyl Selenocarbamates 4 and Te-
Alkenyl Tellurocarbamates 5. Initially, bis(N,N-dimethyl-
carbamoyl) diselenide (1), bis(N,N-diethylcarbamoyl) disele-
nide (10), and bis(N,N-dimethylcarbamoyl) ditelluride (2) were
prepared according to Sonoda’s method30,31 or by ours.32 Ace-
tylenic compounds were efficiently converted into the corre-
sponding ynones 3a–3h through a two-step procedure: (1)
Published on the web March 13, 2007; doi:10.1246/bcsj.80.567

568 Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
Isochalcogenazole
R1
R2
R2
O
R1
X
N
3
6 (X=Se)
7 (X=Te)
O
O
[ H ]
X
X
R2N
NR2
1 (X=Se)
2 (X=Te)
R1
HX
R1
X
R2
R2 NH OSO H
2
3
R2NOC
(Z )
(Z )
N
O
OSO3H
4 (X=Se)
5 (X=Te)
A (X=Se,Te)
1
2
1
2
1
2
1
2
a: R =C H , R =CH ; b: R =R =C H ; c: R =H, R =C H ; d: R =C H , R =p-CH C H ; e:
6
5
3
6
5
2
6
5
6
5
3 6 4
1
2
1
1
2
1
2
R =C H , R =t-C H ; f: R =C H , R =i-C H ; g: R =C H , R =n-C H ; h: R =TMS, R =C H
6 5
6
5
4
9
6
5
3
7
6
5
3
7
Scheme 1. General strategy for preparation of isochalcogenazoles 6 and 7.
Table 1. Preparation of Se-Alkenyl Selenocarbamates 4 and Te-Alkenyl Tellurocarbamates 5aÞ
O
O
O
1) NaBH
4
R1
X
R2
(2.2 mol amt.)
R2N
R2N
X
X
NR2
R1
2)
COR2
C
(Z )
C
1 (X=Se)
2 (X=Te)
O
4 (X=Se)
5 (X=Te)
3 (2.2 mol amt.)
Substrate
X
Ynone 3
R2
Yield of 4 or 5cÞ/%bÞ
Temp
/ꢁC
Time
/h
1 or 2
R
R1
1
1
1
10
2
2
2
2
2
2
2
Se
Se
Se
Se
Te
Te
Te
Te
Te
Te
Te
CH3
CH3
CH3
C6H5
C6H5
H
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
CH3
CH3
C6H5
C6H5
CH3
CH3
ꢂ50
0.25
0.25
2
0.25
7
7
1
7
7
4
Complex mixturecÞ
Complex mixturedÞ
20 (4c)e),f)
ꢂ50
ꢂ50–R.T.
ꢂ50
C2H5
CH3
CH3
CH3
CH3
CH3
CH3
CH3
61 (4a0)e),g)
ꢂ50–R.T.
ꢂ50–R.T.
0
94 (5a)eÞ
C6H5
74 (5b)eÞ
p-CH3C6H4
t-C4H9
i-C3H7
C6H5
61 (5d)eÞ
ꢂ50–R.T.
ꢂ50–R.T.
ꢂ50–R.T.
ꢂ50–R.T.
37 (5e)e),f)
47 (5f)eÞ
Complex mixture
Complex mixture
TMS
C6H5
4
a) All reactions were carried out by treating a C2H5OH solution of 1 (X ¼ Se) or a DMF–C2H5OH solution
of 2 (X ¼ Te) with NaBH4 (2.2 mol amt.) followed by ynone 3 (2.2 mol amt.) to the reaction mixture at the
recorded temperature under an Ar atmosphere. b) Isolated yields based on the starting ynones 3. c) Small
amount of plausible 4a (R1 ¼ C6H5, R2 ¼ CH3) was detected in the mixture by 1H NMR measurement.
d) Small amount of plausible 4b (R1 ¼ R2 ¼ C6H5) was detected in the mixture by 1H NMR measurement.
e) Single geometrical isomers were obtained. f) 4 or 5 was isolated after chromatographic separation of the
complex mixture afforded by the reaction. g) Crude yield after rough chromatographic purification.
C2H5MgBr, (CH3)3SiCl, (2) acetyl chloride, pivaloyl chloride,
isobutyryl chloride, butanoyl chloride, benzoyl chloride, or p-
a one-pot method without isolation and purification of 4 and
40. On the other hand, Te-alkenyl tellurocarbamates 5 were iso-
lated in high to moderate yields as single Z-isomers from the
reaction of 2,36,37 NaBH4, and 3. The results are summarized
in Table 1.
Synthesis of Isoselenazoles 6 and Isotellurazoles 7 by
Treating Se-Alkenyl Selenocarbamates 4 or Te-Alkenyl Tel-
lurocarbamates 5 with Hydroxylamine-O-sulfonic Acid.
Treatment of a CH3OH solution of crude selenocarbamates 4
with hydroxylamine-O-sulfonic acid (4.4 mol amt.) at reflux
under an Ar atmosphere only gave a complex mixture maybe
due to the facile decomposition of 4 during the reaction. How-
ever, a one-pot treatment of a CH3OH solution of 1 (R ¼ CH3)
toluoyl chloride, AlCl3.33 Subsequent treatment of 1 or 10 with
32,34
NaH or NaBH4
(2.2 mol amt.) and ynones 3 only afforded
complex mixtures in all cases. However, in the 1H NMR spec-
tra, the presence of Se-alkenyl selenocarbamates 4 (R ¼ CH3)
or 40 (R ¼ C2H5), respectively,32,35 was observed in the crude
mixture. Compounds 4 (R ¼ CH3) were not stable and under-
went gradual decomposition during the usual workup, chroma-
tographic separation, and storage. Compound 4a0 (R ¼ C2H5)
was relatively stable and was isolated by chromatography;
however, it gradually decomposed. Therefore, subsequent
heterocyclic ring forming reactions were carried out by using

K. Shimada et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
569
1) NaBH (2.2 mol amt.)
4
CH OH, R.T., Ar
3
2) C H
C C COCH (3a)
6
5
3
(2.2 mol amt.)
R.T., 6 h
C6H5
CH3
C6H5
CH3
1
+
+
(R=CH )
Se
N
O
N
3
3) NH OSO H
2
3
(4.2 mol amt.)
MeOH, RT, 5 h
6a (71%)
8a (2%)
1) NaBH (1.1 mol amt.)
4
CH OH-CH CN (1:1)
3
3
2) C H C C COCH
(3a)
3
6
5
(2.5 mol amt.)
0 °C, 30 min
C6H5
CH3
1'
6a (29%)
Se
N
(R=C H )
3) NH OSO H
2
5
2
3
O
(6.0 mol amt.)
EtOH, RT, 2 h
9a (5%)
Scheme 2. One-pot synthesis of isoselenazole 6a, isoxazole 8a, and isoselenazole N-oxide 9a starting from 1 or 10.
However, attempts to prepare a single crystal of 10 for X-
ray crystallographic analysis were unsuccessful. Deoxygena-
tion of 10 was also performed by using PPh3 (1.1 mol amt.)
in CHCl3 in a sealed tube to afford 7 in almost quantitative
yields. The results of the synthesis and the subsequent deoxy-
genation of isotellurazole Te-oxides 10 are given in Table 2.
It was presumed that isochalcogenazole rings would be
formed through a pathway involving acid-induced removal
of a N,N-dialkylcarbamoyl cation from 4 or 5 and subsequent
nucleophilic substitution of the resulting alkeneselenols or al-
kenetellurols A (X ¼ Se and Te)32 on the nitrogen atoms of the
in situ formed oxime sulfonates.42–47 However, no methanoly-
sis products, O-methyl N,N-dimethylselenocarbamate, were
found in the crude reaction mixture, and thus, this pathway
was negligible. In addition, reaction of crude selenocarbamate
4a0 (R ¼ C2H5, R1 ¼ C6H5, R2 ¼ CH3) with hydroxylamine-
O-sulfonic acid in the presence of allyltrimethylsilane (10
mol amt.) in methanol to trap the N,N-dialkylcarbamoyl cation
only afforded a mixture containing isoxazole 8a (35%), iso-
selenazole 6a (13%), and an intractable mixture, and N,N-di-
ethylbutenamide, the allylation product of N,N-diethylcarba-
moyl cation, was not found in the crude mixture.
Isoselenazoles 6 and isotellurazoles 7 were reasonably sta-
ble toward exposure to air, and further treatment of isotellura-
zole 7a with an excess amount of hydroxylamine-O-sulfonic
acid under a similar condition (methanol, reflux, 2 h) only re-
sulted in the complete recovery of 7a. On the other hand,
mCPBA oxidation of 7 in CHCl3 at 0 ꢁC only resulted in form-
ing a complex mixture containing isoxazoles 8. These results
suggest that the formation pathway of 9 and 10 does not in-
volve the oxidation of 6 and 7, respectively. The formation
pathway of isoselenazole N-oxide 9 and isotellurazole Te-
oxides 10 through the reaction of 4 and 5 with hydroxyl-
amine-O-sulfonic acid is still unclear.
Fig. 1. ORTEP drawing of isoselenazole N-oxide 9a.
with NaBH4, ynone 3a, and hydroxylamine-O-sulfonic acid af-
forded isoselenazole 6a (71%)21,22 and isoxazole 8a (2%)38–41
as well as complex mixture, and a similar treatment of a
CH3CN solution of 10 (R ¼ C2H5) afforded a mixture of iso-
selenazole 6a (29%) and its N-oxide 9a (5%), as shown in
Scheme 2. These results indicated that the crude mixture ob-
tained from the reaction of 3 with 1/NaBH4 contained 4 as
the main components. The structure of 9a was determined
by X-ray crystallographic analysis, and an ORTEP drawing
of 9a is shown in Fig. 1. Compound 9a was converted into
6a in 88% yield by treating with PPh3 (1.1 mol amt.) in CHCl3
at refluxing temperature for 50 h. Compound 6a was reasona-
bly stable in air, and treatment of 6a with m-chloroperbenzoic
acid (mCPBA) or an aqueous hydrogen peroxide solution only
caused decomposition affording a complex mixture containing
isoxazole 8a as a minor component. The actual pathway for the
formation of 9a is still unclear at this time, but this result clear-
ly showed that the oxidation of 6a is not involved.
A similar treatment of a CH3OH solution of Te-alkenyl tel-
lurocarbamates 5 with hydroxylamine-O-sulfonic acid afford-
ed air-stable isotellurazole Te-oxides 10 as well as a trace
amount of isotellurazoles 7.21,22 In the mass spectra, the parent
ion peaks of 10 were observed along with the isotope distribu-
tion pattern for one tellurium atom. The 1H NMR spectra of 10
also showed a new signal assigned to the vinyl proton of the
C-4 position of isotellurazole ring, and the 125Te NMR signal
of 10b (ꢂ ¼ 3831) was shifted significantly downfield com-
pared to that of 7b (ꢂ ¼ 1676). The similarity in the patterns
of 1H NMR and 13C NMR spectra of 10b to those of 7b, except
for the downfield shift of the 125Te NMR signal, strongly indi-
cated the existence of telluroxide moiety, not N-oxide, in 10.
Attempts at an Alternative Synthesis of Isoselenazoles 6
and Isotellurazoles 7. Ynones 3 have generally been recog-
nized as Michael accepters, and therefore, nucleophilic 1,4-at-
tack of chalcogenide ions to ynone oxime derivatives bearing a
leaving group on the oxime nitrogen should result in further
cyclization to form isochalcogenazoles 6 and 7 via intramolec-
ular nucleophilic substitution on the oxime nitrogen.

570 Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
Table 2. Syntheses of Isotellurazole Te-Oxides 10 and Isotellurazoles 7aÞ
Isochalcogenazole
O
R1
Te
NH OSO H
R1
R2
R1
R2
2
3
R2
(4.4 mol amt.)
Me2N
+
Te
N
Te
N
MeOH
reflux, 2 h
O
7
O
5
10
PPh (1.1 mol amt.)
3
CHCl , 100 °C, 1 h
3
Substrate
R2
Yield/%
Yield/% of
deoxygenationbÞ
R1
5
10
7
10 to 7
Ph3P=O
C6H5
C6H5
C6H5
C6H5
CH3
C6H5
p-CH3C6H5
t-C4H9
5a
5b
5d
5e
79 (10a)
86 (10b)
74 (10d)
67 (10e)
4 (7a)
trace (7b)
0
0
91 (7a)
94 (7b)
89 (7d)
quant.
quant.
quant.
cÞ
—
a) All reactions were carried out under an Ar atmosphere. b) Carried out in a sealed tube. c)
Not attempted.
Table 3. Reaction of Ynone Oxime Tosylates 12 with NaSeH or NaTeH
R1
R2
R1
N
R2
R1
R2
R2
X / NaBH
EtOH
4
R1
+
+
Se Se
O
N
X
N
N
OTs
0 °C, 0.5 h
6 (X=Se)
7 (X=Te)
12
8
13
(X=Se,Te)
Substrate
Chalcogen X
Yield/%aÞ
R1
R2
12
Major:MinorbÞ
6
8
13
C6H5
C6H5
C6H5
C6H5
C6H5
CH3
C6H5
n-C3H7
CH3
12a
12b
12g
12a
12b
10:1
10:1
5:1
10:1
10:1
Se
Se
Se
Te
Te
41 (6a)
0
43 (6g)
0cÞ
0cÞ
38 (8a)
59 (8b)
40 (8g)
Trace (8a)
Trace (8b)
0
38 (13b)
0
—
—
C6H5
a) Isolated yields. b) Determined by integration of the signals of the 1H NMR spectrum of oxime tosylates 12.
c) Complex mixture was obtained.
Ynone oximes 11 were easily prepared by the reaction of
ynones 3, hydroxylamine hydrochloride, and sodium acetate,
and oximes 11 were easily converted into the mixtures of
syn–anti geometrical isomers of oxime tosylates 12 by treating
them with p-toluenesulfonyl chloride and triethylamine. It was
noteworthy that oxazoles 8 were formed as byproducts of the
tosylation in most cases through base-induced ring closure of
11. Subsequently, when an oxime tosylate 12 was treated with
NaSeH, generated in situ by treating elemental selenium with
NaBH4 in ethanol, isoselenazole 6 and isoxazole 8 were main-
ly obtained. All the results of reactions of oxime tosylates 12
with NaSeH are shown in Table 3. Interestingly, 1,2-diselenole
13b, instead of isoselenazole 6b, was obtained along with iso-
xazole 8b by starting from oxime tosylate 12b (R1 ¼ R2 ¼
C6H5). All the spectral data of 13b, involving MS, IR,
1H NMR, and 13C NMR spectra, as well as elemental analysis
data, were fully consistent with the structure. Selena-Beckmann
rearrangement of oxime sulfonates has already been reported
by Segi and Nakajima which involves the treatment of oxime
mesylates with (Me2Al)2Se,48 and 13b was also regarded as a
selena-Beckmann product of 12b. The structure of 13b was de-
termined by X-ray crystallographic analysis, and an ORTEP
drawing of 13b is shown in Fig. 2. It was worth noting that
Fig. 2. ORTEP drawing of 13b.
the some intermolecular attractive Se–N–Se interaction, i.e.
˚
˚
Se(1){N ¼ 3:52 A and Se(2){N ¼ 3:58 A, respectively, was
found in the crystal packing structure of 13b as shown in Fig. 3.
On the other hand, similar reactions of 12 with NaTeH only
gave intractable mixtures, and isotellurazoles 7 were not found
in the crude products. NaTeH is widely known to behave as
a reducing agent and as a divalent tellurium nucleophile to
afford dialkenyl ditellurides from the reactions with various
substrates having acetylenic moieties, imine moieties, and
hydroxylamine derivatives,49–59 and this might have caused
the complicated mixture in our case.
In contrast, when ynone oxime tosylate 12a was treated with
N,N-dimethylcarbamoylchalcogenide ion, generated in situ

K. Shimada et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
571
through reductive cleavage of 1 or 2 using NaBH4, the corre-
sponding isochalcogenazole 6a or 7a, respectively, was mainly
afforded without the formation of isoxazole 8a and oxidation
products (9a and 10a). In addition, tosylate 15a was obtained
in low yield as the sole geometrical isomer in the case starting
from 2 as shown in Table 4.
explained by the cleavage of tosyloxy group to generate free
oximes 11 through the nucleophilic attack of hydroselenide
ion (SeHꢂ) to the sulfur atom of the tosyloxy moiety of 12.
A plausible reaction pathway for the formation of isoselena-
zoles 6, isoxazoles 8, and 1,2-diselenole 13b is summarized
as shown in Scheme 3.
It should be noted that 13b was not unexpected from selena-
Beckmann rearrangement of 12b. Presumably, conversion of
12b into 13b is initiated by Michael addition of NaSeH to
the ꢀ-position of ynone oxime tosylates 12 to form general in-
termediates B, and the formation of 6 can be explained by in-
tramolecular nucleophilic substitution of intermediary alkene-
selenolate ions C to the nitrogen atom of the oxime sulfonates.
However, when an aryl group is bound at the R2 position, sub-
sequent 1,2-shift of aryl group from the oxime carbon atom to
the nitrogen atom along with elimination of tosyloxy group
might proceed predominantly,46,60–62 and further addition of
hydroselenide ion (SeHꢂ) to the newly formed iminocarbon
of ketenimine D occurs. The final aerobic oxidation during
the usual workup would afford 1,2-diselenole 13b. The forma-
tion of 8 through the reaction of 12 with NaSeH can also be
Conclusion
In conclusion, we found several new methods for the syn-
thesis of isochlcogenazoles 6 and 7 starting from bis(N,N-di-
alkylcarbamoyl) dichalcogenides 1, 10, and 2 and ynones 4 in-
volving the intramolecular nucleophilic substitution of ene-
chalcogenolate ions on the nitrogen atoms of in situ generated
ynone oxime sulfonates. Especially, the reactions of Te-alken-
yl tellurocarbamates 5 with hydroxylamine-O-sulfonic acid
gave the best results for the formation of isotellurazole ring
system among these new methods. Further attempts to syn-
thesize various fused heterocycles via hetero Diels–Alder
approach using these higher-row isochalcogenazoles as novel
4ꢁ components bridged with a heavy chalcogen atom are un-
der way in our laboratory.
Experimental
Instruments. Melting points were determined with a Buchi
¨
535 micro-melting-point apparatus. 1H NMR spectra were record-
ed on a Hitachi R-22 (90 MHz) or a Bruker AC-400P (400 MHz)
1
spectrometer, and the chemical shifts of the H NMR spectra are
given as ꢂ relative to internal tetramethylsilane (TMS). 13C NMR
spectra were recorded on
a Bruker AC-400P (100 MHz).
77Se NMR spectra and 125Te NMR spectra were recorded on a
Bruker AC-400P (76 and 125 MHz), and the chemical shifts of
the 77Se NMR and 125Te NMR spectra are given in ꢂ relative to
external standard of dimethyl selenide and dimethyl telluride, re-
spectively. Mass spectra were recorded on a Hitachi M-2000 mass
spectrometer with electron-impact ionization at 20 or 70 eV using
a direct inlet system. IR spectra were recorded for thin-film (neat)
or KBr disks on a JASCO FT/IR-7300 spectrometer. Elemental
analyses were performed using a Yanagimoto CHN corder MT-5.
Materials. Column chromatography was performed using
silica gel (Merck, Cat. No. 7734 or 9385) without pretreatment.
Dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon
tetrachloride (CCl4) were dried over P4O10 and were freshly
Fig. 3. Crystal structure of 13b.
Table 4. Reaction of Ynone Oxime Tosylate 12a with Bis(N,N-dimethylcarbamoyl) Dichalco-
genide 1 and 2 and NaBH4
O
1) NaBH , CH OH
R2
4
3
R1
O
O
Ph
-50 °C, 15 min
CH3
+
Me2N
X
X
N
CH3
OTs
Me2N
X
X
NMe2
2) Ph
N
6 (X=Se)
7 (X=Te)
14 (X=Se)
15 (X=Te)
1 (X=Se)
2 (X=Te)
N
OTs
12a
1 or 2
X
Yield/%bÞ
NaBH4
Temp
/ꢁC
Time
/mol amt.
/h
6 or 7
14 or 15
0cÞ
23 (15a)
22 (15a)
1
2
2
Se
Te
Te
2.2
2.2
4.4
R.T.
R.T.
40
4
7
7
14 (6a)
12 (7a)
30 (7a)
a) A methanolic solution of 1 or 2 was treated with NaBH4 at ꢂ50 ꢁC for 15 min, and the result-
ing reaction mixture was treated with ynone oxime tosylate 12a under the condition described in
the table. b) Isolated yields. c) Complex mixture was obtained.

572 Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
Isochalcogenazole
2
R
1
R
N
OTs
12
NaSeH
2
R
2
1
R
R
1
•
R
HSe
N
OTs
N
O
B
(R2=Alkyl)
(R2=Ar)
- TsO
1
1
H
R
R
2
•
•
R
N
2
R
Se
HSe
D
N
OTs
NaSeH
C
1
R
HSe
N
2
HSe
R
- TsO
[ O ]
13
6
8
Scheme 3. Plausible formation pathway of isoselenazoles 6, 1,2-diselenole 13a, and isoxazoles 8 through the reaction of oxime
tosylates 12 with NaSeH.
distilled before use. Benzene, hexane, acetonitrile, triethylamine,
and N,N-dimethylformamide (DMF) were dried over calcium hy-
dride (CaH2) and freshly distilled before use. Diethyl ether and
tetrahydrofuran (THF) were dried over lithium tetrahydridoalumi-
nate (LiAlH4) and was freshly distilled before use. Ethanol and
methanol were dried over anhydrous magnesium sulfate (MgSO4)
and were freshly distilled before use. All of the substrates, NMR
solvents, and reagents, including elemental selenium, elemental
tellurium, sodium metal, diethylamine, carbon monoxide (gas),
phenylacetylene, trimethylsilylacetylene, ethyl bromide, magnesi-
um metal, trimethylchlorosilane, anhydrous aluminium trichloride
(AlCl3), acetyl chloride, pivaloyl chloride, butanoyl chloride, iso-
butyryl chloride, benzoyl chloride, p-toluoyl chloride, sodium hy-
dride (NaH) in a mineral oil (about 50%), sodium tetrahydroborate
(NaBH4), lithium tetrahydridoaluminate (LiAlH4), hydroxyl-
amine-O-sulfonic acid, hydroxylamine hydrochloride, sodium
acetate, p-toluenesulfonyl chloride, triphenylphosphine, m-chloro-
perbenzoic acid (mCPBA), anhydrous sodium sulfate (Na2SO4),
anhydrous magnesium sulfate (MgSO4), 34.5% aqueous hydrogen
peroxide solution, acetic acid, concentrated hydrochloric acid, and
deuteriochloroform (CDCl3), were commercially available re-
agent grade and were used without any pretreatment.
at ꢂ50 ꢁC, and the reaction mixture was then treated with ynone 3
(2.2 mol amt.) at 0 ꢁC for 7 h. The reaction was quenched with
water, and the reaction mixture was extracted with benzene. The
organic layer was washed twice with water and was dried over
anhydrous Na2SO4 powder. The organic solvent was removed in
vacuo, and the residual crude mixtures were subjected to chroma-
tographic separation. However, purification of unstable Se-alkenyl
N,N-dimethylselenocarbamates 4 was not successful even after re-
peated column chromatography on silica gel. On the other hand,
the corresponding N,N-diethylselenocarbamates 40 were relatively
stable and were isolated in low yield as an yellow oil.
4a0 (R ¼ C2H5, R1 ¼ C6H5, R2 ¼ CH3): Yellow oil; IR (neat)
2975, 1665, 1548, 1402, 1245, 1212, 1111, 842, 750, 697 cmꢂ1
;
1H NMR (CDCl3) ꢂ 0.90 (3H, t, J ¼ 7:0 Hz), 1.25 (3H, t, J ¼
7:0 Hz), 2.33 (3H, s), 3.18 (2H, q, J ¼ 7:0 Hz), 3.46 (2H, q, J ¼
7:0 Hz), 6.90 (1H, s), 7.32–7.34 (3H, m), 7.50–7.52 (2H, m).
4c (R ¼ CH3, R1 ¼ H, R2 ¼ C6H5): Yellow plates, mp 103.5–
104.8 ꢁC (dec.); MS (m=z) 283 (Mþ; 5%, 80Se), 131 (C6H5-
COCH=CH; 31%), 72 (Me2NCO; bp); IR (KBr) 1618, 1600,
1503, 1332, 1211, 1089, 828, 766, 700, 560 cmꢂ1 1H NMR
;
(CDCl3) ꢂ 3.11 (3H, s), 3.12 (3H, s), 7.47–7.51 (2H, m), 7.56–
7.59 (1H, m), 7.72 (1H, d, J ¼ 9:3 Hz), 8.02–8.03 (2H, m), 8.79
(1H, d, J ¼ 9:3 Hz); 13C NMR (CDCl3) ꢂ 33.7 (q), 37.3 (q), 120.1
(d), 128.2 (d), 128.9 (d), 132.9 (d), 137.4 (s), 146.7 (d), 164.6 (s),
189.5 (s). Calcd for C12H13NO2Se: C, 51.07; H, 4.64; N, 4.96%.
Found: C, 50.91; H, 4.53; N, 4.72%.
General Procedure for Preparation of Se-Alkenyl Seleno-
carbamates 4. To a DMF solution (10 mL) of bis(N,N-dimethyl-
carbamoyl) diselenide (1, 616 mg, 2.00 mmol)30–32 or bis(N,N-di-
ethylcarbamoyl) diselenide (10, 716 mg, 2.00 mmol)30,32 was add-
ed a methanolic solution (5 mL) of NaBH4 (168 mg, 2.2 mol amt.)
General Procedure for Preparation of Te-Alkenyl Telluro-

K. Shimada et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
573
carbamates 5. To a DMF solution (10 mL) of bis(N,N-dimethyl-
carbamoyl) ditelluride (2, 398 mg, 1.00 mmol) was added a meth-
anolic solution (5 mL) of NaBH4 (84 mg, 2.2 mol amt.) at ꢂ50 ꢁC,
and the reaction mixture was then treated with ynone 3 (2.2
mol amt.) at 0 ꢁC for 7 h. The reaction was quenched with water,
and the reaction mixture was extracted with benzene. The organic
layer was washed twice with water and was dried over anhydrous
Na2SO4 powder. The organic solvent was removed in vacuo, and
the residual crude products were subjected to column chromatog-
raphy on silica gel to obtain Te-alkenyl N,N-dimethyltellurocarba-
mates 5 in high to moderate yields as yellow crystals.
nide (1 or 10). An acetonitrile solution (10 mL) of bis(N,N-di-
methylcarbamoyl) diselenide (1) or bis(N,N-diethylcarbamoyl)
diselenide (10) was treated with NaBH4 (1.0–2.2 mol amt.) at room
temperature for 30 min under an Ar atmosphere, and the reaction
mixture was treated with ynone 3 (2.20–2.50 mol amt.) at room
temperature for 2–6 h. The reaction was quenched with water
and was extracted with CHCl3. The organic layer was washed
with water, and was dried over anhydrous Na2SO4 powder. The
organic solvent was removed in vacuo, and ethanol (20 mL) was
added to the residual crude products. Then, a methanolic or an
ethanolic solution of the crude products was then treatment with
hydroxylamine-O-sulfonic acid (4.0–6.0 mol amt.) at room tem-
perature for a few hours. The reaction was quenched by large
amount of water, and the reaction mixture was extracted with
chloroform. The organic layer was washed with water, and was
dried over anhydrous Na2SO4 powder. The organic solvent was
removed in vacuo, and the residual crude products were subjected
to column chromatography on silica gel to obtain isoselenazoles
6a, isoxazole 8a, and isoselenazole N-oxides 9a.
5a (R1 ¼ C6H5, R2 ¼ CH3):32 Yellow solid, mp 67.0–67.5 ꢁC;
MS (m=z) 347 (Mþ; 3%, 130Te), 345 (Mþ; 2%, 128Te), 275 (Mþ ꢂ
Me2NCO; 55%, 130Te), 273 (Mþ ꢂ Me2NCO; 53%, 128Te), 271
(Mþ ꢂ Me2NCO; 31%, 126Te), 43 (CH3CO; bp); IR (KBr) 2924,
1637, 1609, 1522, 1483, 1359, 1089, 822, 761, 702, 646 cmꢂ1
;
1H NMR (CDCl3) ꢂ 2.34 (3H, s), 2.60 (3H, br s), 2.77 (3H, br s),
7.35–7.65 (6H, m). Calcd for C13H15NO2Te: C, 45.28; H, 4.38; N,
4.06%. Found: C, 44.97; H, 4.38; N, 3.77%.
5b (R1 ¼ R2 ¼ C6H5): Orange needles, mp 101.3–102.7 ꢁC;
MS (m=z) 409 (Mþ; 3%, 130Te), 330 (Mþ ꢂ C6H5; 84%, 128Te),
251 (Mþ ꢂ 2(C6H5); 24%, 126Te), 202 (Me2NCO, 81%), 172
(NCOTe; 1%, 130Te), 72 (Me2NCO; bp); IR (KBr) 1606, 1481,
1238, 1086, 758, 697 cmꢂ1; 1H NMR (CDCl3) ꢂ 2.59 (3H, s), 2.80
(3H, s), 7.36–7.40 (3H, m), 7.47–7.51 (4H, m), 7.55–7.58 (1H, m),
8.04–8.06 (2H, m), 8.13 (1H, s); 13C NMR (CDCl3) ꢂ 33.6 (q),
41.7 (q), 126.5 (d), 127.8 (d), 128.2 (d), 128.4 (d), 128.7 (d), 129.0
(d), 132.9 (d), 137.3 (s), 143.8 (s), 161.4 (s), 162.0 (s), 188.5 (s).
Calcd for C18H17NO2Te: C, 53.13; H, 4.21; N, 3.44%. Found: C,
53.00; H, 4.18; N, 3.30%.
6a (R1 ¼ C6H5, R2 ¼ CH3): Pale yellow needles, mp 72.1–
72.9 ꢁC (lit.,37 73.0–75.0 ꢁC); MS (m=z) 223 (Mþ; bp, 80Se), 182
(Mþ ꢂ CH3CN; 36%, 80Se), 102 (C6H5C=CH; 48%); IR (KBr)
3059, 2925, 1546, 1491, 1448, 1377, 1344, 827, 762, 732 cmꢂ1
;
1H NMR (CDCl3) ꢂ 2.48 (3H, s), 7.35–7.39 (4H, m), 7.50–7.52
(2H, m); 13C NMR (CDCl3) ꢂ 21.6 (q), 123.1 (d), 126.9 (d),
129.1 (d), 133.6 (s), 171.5 (s), 172.5 (s); 77Se NMR (CDCl3) ꢂ
602.6. Calcd for C10H9NSe: C, 54.07; H, 4.08; N, 6.31%. Found:
C, 54.18; H, 4.10; N, 6.06%.
8a (R1 ¼ C6H5, R2 ¼ CH3):38–41,63 Colorless needles, mp
64.5–66.0 ꢁC (lit.,38 65.0–67.0 ꢁC).
5d (R1 ¼ C6H5, R2 = p-CH3C6H4): Orange plates, mp 130.5–
131.0 ꢁC (dec.); MS (m=z) 423 (Mþ; 5%, 130Te), 73 (Me2NCO þ
1; bp); IR (KBr) 1618, 1600, 1503, 1332, 1211, 1089, 828, 766,
9a (R1 ¼ C6H5, R2 ¼ CH3): Yellow plates, mp 135.3–136.0
ꢁC; MS (m=z) 239 (Mþ; 34%, 80Se), 223 (Mþ ꢂ O; 67%, 80Se);
IR (KBr) 3067, 2994, 1543, 1412, 1247, 1200, 939, 882, 823,
1
700, 560 cmꢂ1; H NMR (CDCl3) ꢂ 2.41 (3H, s), 2.59 (3H, br s),
758 cmꢂ1 1H NMR (CDCl3) ꢂ 2.27 (3H, s), 6.78 (1H, s), 7.28–
;
2.81 (3H, br s), 7.28–7.30 (2H, m), 7.36–7.38 (3H, m), 7.48–7.50
(2H, m), 7.90–7.95 (2H, m), 8.11 (1H, s); 13C NMR (CDCl3) ꢂ
21.7 (q), 33.7 (q), 41.7 (q), 126.6 (d), 127.8 (d), 128.4 (d), 128.5
(d), 128.9 (d), 129.5 (d), 134.9 (s), 160.6 (s), 162.2 (s), 188.2 (s).
125Te NMR (CDCl3) ꢂ ¼ ꢂ192:7. Calcd for C19H19NO2Te: C,
54.21; H, 4.55; N, 3.33%. Found: C, 54.02; H, 4.38; N, 3.21%.
5e (R1 ¼ C6H5, R2 = t-C4H9): Yellow prisms, mp 89.0–89.3
ꢁC (dec.); MS (m=z) 392 (Mþ; 5%, 130Te), 389 (Mþ; 3%, 128Te),
317 (bp); IR (KBr) 2966, 1687, 1618, 1512, 1484, 1364, 1248,
7.38 (5H, m); 13C NMR (CDCl3) ꢂ 14.5 (q), 116.2 (d), 125.7 (d),
129.2 (d), 132.8 (s), 148.2 (s), 149.3 (s). Calcd for C10H9NOSe: C,
50.43; H, 3.81; N, 5.88%. Found: C, 50.85; H, 3.87; N, 5.94%.
X-ray Crystallographic Analysis of Isoselenazole N-Oxide
9a. A single crystal with sizes of 0:25 ꢃ 0:10 ꢃ 0:04 mm3 was
mounted on a Rigaku MSC Mercury CCD diffractometer, equip-
ped with a rotating anode (50 kV, 40 mA), using graphite-mono-
˚
chromated Mo Kꢃ radiation (ꢄ ¼ 0:71070 A). Crystal data are
˚
as follows: a ¼ 8:942ð2Þ, b ¼ 5:817ð1Þ, c ¼ 17:812ð4Þ A, ꢀ ¼
1
ꢁ
3
1217, 1087, 1013, 948, 761, 699, 663 cmꢂ1; H NMR (CDCl3) ꢂ
102:016ð5Þ , V ¼ 906:2ð3Þ A , space group = P21=n (No. 14),
˚
1.24 (9H, s), 2.59 (3H, br s), 2.80 (3H, br s), 7.34–7.35 (3H, m),
7.41–7.43 (2H, m), 7.58 (1H, s); 13C NMR (CDCl3) ꢂ 25.6 (q),
33.7 (q), 41.7 (q), 42.9 (q), 126.5 (d), 127.8 (d), 128.4 (d), 128.8
(d), 143.8 (s), 158.3 (s), 161.7 (s), 204.6 (s). Calcd for C16H21-
NO2Te: C, 49.66; H, 5.48; N, 3.62%. Found: C, 49.45; H, 5.53;
N, 3.54%.
Z ¼ 4, Dcalcd ¼ 1:745 g cmꢂ3, ꢅ(Mo Kꢃ) = 40.98 cmꢂ1
. The
2ꢆ–! scan mode with a scan rate of 8ꢁ minꢂ1 (!) was employed
with a scan range (1:20 þ 0:30 tan ꢆ). A total of 8316 reflection
within 2ꢆ ¼ 55:0ꢁ was collected. The structure was solved by
the direct method and refined by the full-matrix least-square meth-
od. All non-hydrogen atoms were refined anisotropically and
hydrogen atoms found in the successive D-Fourier map were re-
fined isotropically. The final cycle of refinement was carried out
using 1521 observed reflections within Io > 2:5ꢇðIoÞ converged
5f (R1 ¼ C6H5, R2 = i-C3H7): Yellow needles, mp 97.4–97.6
ꢁC (dec.); MS (m=z) 375 (Mþ; 5%, 130Te), 299 (bp); IR (KBr)
2960, 1701, 1637, 1488, 1362, 1249, 1084, 881, 759, 696, 669
1
cmꢂ1; H NMR (CDCl3) ꢂ 1.19 (3H, br d, J ¼ 7:0 Hz), 1.21 (3H,
to the final R ¼ ꢀjjFoj ꢂ jFcjj=ꢀFoj value of 0.032 and Rw ¼
2
1=2
2
br d, J ¼ 7:0 Hz), 2.59 (3H, br s), 2.80 (3H, br s), 2.80 (1H, septet,
J ¼ 7:0 Hz), 7.33–7.43 (6H, m); 13C NMR (CDCl3) ꢂ 18.4 (q),
33.8 (q), 40.7 (q), 41.6 (q), 127.8 (d), 128.4 (d), 128.7 (d), 128.8
(d), 143.5 (s), 157.5 (s), 161.4 (s), 203.2 (s). Calcd for C15H19-
NO2Te: C, 48.31; H, 5.14; N, 3.76%. Found: C, 48.19; H, 5.04;
N, 3.65%.
½ðꢀwðjFoj ꢂ jFcjÞ =ꢀwFo Þꢄ of 0.098. The maximum and min-
imum peaks on the final difference Fourier map correspond to
0.46 and ꢂ0:54 eAꢂ3, respectively. Selected bond lengths and
˚
bond angles are listed in Table 5. Crystallographic data have been
deposited at the CCDC, 12, Union Road, Cambridge, CB2 1EZ,
UK, and the copies can be obtained on request, free of charge,
by quoting the publication citation and the deposition number
CCDC-620036.
General Procedure for Synthesis of Isoselenazoles 6 and
Their N-Oxides 11 from Bis(N,N-dialkylcarbamoyl) Disele-

574 Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
Isochalcogenazole
Table 5. Bond Lengths and Bond Angles for Isoselenazole
N-Oxide 9a
C15H11NOTe: C, 51.64; H, 3.18; N, 4.02%. Found: C, 51.09; H,
3.01; N, 3.89%.
10d (R1 ¼ C6H5, R2 = p-CH3C6H4): Orange oil; MS (m=z)
˚
Bond lengths/A
365 (Mþ; 2%, 130Te), 102 (C6H5C2H; bp); IR (oil) 2922, 1537,
;
1486, 1444, 1341, 1276, 758, 692 cmꢂ1 1H NMR (CDCl3) ꢂ
Bond angles/deg
N(1)–Se(1)–C(1)
Se(1)–N(1)
1.898(2)
1.874(2)
1.284(3)
1.317(3)
1.353(4)
1.472(4)
1.414(4)
1.498(4)
86.4(1)
121.1(2)
112.0(2)
126.9(2)
109.8(2)
121.3(2)
128.8(2)
117.3(2)
114.5(2)
119.7(2)
125.7(2)
121.3(2)
120.2(2)
Se(1)–C(1)
O(1)–N(1)
N(1)–C(3)
C(1)–C(2)
C(1)–C(5)
C(2)–C(3)
C(3)–C(4)
Se(1)–N(1)–O(1)
Se(1)–N(1)–C(3)
O(1)–N(1)–C(3)
Se(1)–C(1)–C(2)
Se(1)–C(1)–C(5)
C(2)–C(1)–C(5)
C(1)–C(2)–C(3)
N(1)–C(3)–C(2)
N(1)–C(3)–C(4)
C(2)–C(3)–C(4)
C(1)–C(5)–C(6)
C(1)–C(5)–C(10)
2.39 (3H, s), 7.24–7.26 (3H, m), 7.39–7.42 (3H, m), 7.50–7.52
(2H, m), 7.83–7.85 (1H, m), 8.62 (1H, s); 13C NMR (CDCl3) ꢂ
21.5 (q), 127.1 (d), 127.4 (d), 127.6 (d), 128.3 (d), 128.55 (d),
128.63 (d), 129.1 (s), 129.6 (s), 139.3 (s), 140.8 (s), 165.9 (s).
Calcd for C16H13NOTe: C, 52.96; H, 3.61; N, 3.86%. Found: C,
52.53; H, 3.46; N, 3.74%.
10e (R1 ¼ C6H5, R2 = t-C4H9): Pale yellow oil; MS (m=z) 331
(Mþ; 6%, 130Te), 329 (Mþ; 6%, 128Te), 327 (Mþ; 3%, 126Te), 315
(Mþ ꢂ O; bp, 130Te), 313 (Mþ ꢂ O; 72%, 128Te), 311 (Mþ ꢂ O;
34%, 126Te); IR (KBr) 2924, 1573, 1493, 1468, 1375, 1344, 1219,
1105, 928, 871, 835, 759, 696 cmꢂ1 1H NMR (CDCl3) ꢂ 1.09
;
(9H, s), 7.36–7.52 (6H, m); 125Te NMR (CDCl3) ꢂ 3782. Calcd
for C13H15NOTe: C, 47.48; H, 4.60; N, 4.26%. Found: C, 47.12;
H, 4.43; N, 4.15%.
General Procedure for Deoxygenation of Isoselenazole Se-
Oxide 9a Using Triphenylphosphine. A CHCl3 solution of
isoselenazole N-oxide 9a (R1 ¼ C6H5, R2 ¼ CH3, 238 mg, 1.00
mmol) was treated with triphenylphosphine (289 mg, 1.1 mol amt.)
at reflux for 50 h, and the reaction was quenched by cooling the
reaction mixture at 0 ꢁC in an ice bath. The organic solvent was
then removed in vacuo, and the residual crude products were sub-
jected to column chromatography on silica gel to obtain isoselena-
zole 6a (198 mg, 89% yield) along with the formation of quantita-
tive amount of triphenylphosphine oxide.
General Procedure for Synthesis of Isotellurazole Te-Oxides
10 by Treating Te-Alkenyl Tellurocarbamates 5 with Hydrox-
ylamine-O-sulfonic Acid. A methanolic solution (10 mL) of
Te-alkenyl N,N-dimethyltellurocarbamates 5 was treated with
hydroxylamine-O-sulfonic acid (4.4 mol amt.) at reflux for 1 h.
The reaction mixture was cooled to room temperature and was
quenched with water, and the crude reaction mixture was extract-
ed with benzene. The organic layer was washed with water and
was dried over anhydrous Na2SO4 powder. The organic solvent
was removed in vacuo, and the residual crude products were sub-
jected to column chromatography on silica gel to obtain isotellura-
zole Te-oxides 10 as main products besides a small amount of iso-
tellurazoles 7.
General Procedure for Deoxygenation of Isotellurazole Te-
Oxides 10 Using Triphenylphosphine. A CHCl3 solution of iso-
tellurazole Te-oxides 10 (1.00 mmol) was treated with triphenyl-
phosphine (1.1 mol amt.) at 100 ꢁC for 12 h in a sealed tube, and
the reaction vessel was cooled to 0 ꢁC in an ice bath to quench
the reaction. The organic solvent was then removed in vacuo,
and the residual crude products were subjected to column chroma-
tography on silica gel to obtain isotellurazoles 7 in high yields
along with quantitatively formed triphenylphosphine oxide.
7a (R1 ¼ C6H5, R2 ¼ CH3): Pale yellow needles, mp 147.5–
148.0 ꢁC (lit.,22 149.0–150.0 ꢁC), MS (m=z) 273 (Mþ; 67%,
130Te), 271 (Mþ; 63%, 128Te), 269 (Mþ; 63%, 126Te), 268 (Mþ;
1
bp, 125Te), 228 (88%); IR (KBr) 1551, 1314, 696 cmꢂ1; H NMR
(CDCl3) ꢂ 2.51 (3H, s), 7.36–7.38 (3H, m), 7.43–7.45 (2H, m),
8.01 (1H, s); 13C NMR (CDCl3) ꢂ 25.7 (q), 127.5 (d), 129.1 (d),
129.2 (d), 132.8 (d), 137.9 (s), 170.2 (s), 177.0 (s). 125Te NMR
(CDCl3) ꢂ 1676.
7b (R1 ¼ R2 ¼ C6H5): Pale yellow powder, mp 140.5–141.0
ꢁC; MS (m=z) 335 (Mþ; 130Te), 333 (Mþ; 128Te), 205 (Mþ ꢂ Te;
bp); IR (KBr) 1535, 1482, 1442, 1392, 1098, 1028, 847, 837, 753,
689 cmꢂ1; 1H NMR (CDCl3) ꢂ 7.35–7.50 (6H, m), 7.73–7.75 (2H,
m), 7.94–7.95 (2H, m), 8.65 (1H, s); 13C NMR (CDCl3) ꢂ 129.2
(d), 129.3 (d), 130.6 (d), 131.50 (d), 131.52 (d), 132.1 (d), 132.6
(d), 138.1 (d), 140.5 (s), 171.4 (s), 176.6 (s). Calcd for C15H11-
NTe: C, 54.13; H, 3.33; N, 4.21%. Found: C, 54.01; H, 3.15; N,
4.09%.
10a (R1 ¼ C6H5, R2 ¼ CH3): Ivory powder, mp 210.3–211.8
ꢁC (dec.); MS (m=z) 289 (Mþ; 10%, 130Te), 287 (Mþ; 13%,
128Te), 285 (Mþ; 9%, 126Te), 273 (Mþ ꢂ O; 61%, 130Te), 271
(Mþ ꢂ O; 60%, 128Te), 269 (Mþ ꢂ O; 76%, 126Te), 102 (C6H5-
C2H; bp); IR (KBr) 3050, 2917, 1570, 1492, 1467, 1441, 1372,
1342, 1221, 1164, 1022, 925, 905, 868, 831, 758, 694,
7d (R1 ¼ C6H5, R2 = p-CH3C6H4): Orange oil; MS (m=z) 349
(Mþ; 35%, 130Te), 219 (Mþ ꢂ Te; bp); IR (oil) 2922, 1537, 1486,
1
1444, 1341, 1276, 758, 692 cmꢂ1; H NMR (CDCl3) ꢂ 2.39 (3H,
1
616 cmꢂ1; H NMR (CDCl3) ꢂ 1.68 (3H, s), 7.05 (1H, s), 7.24–
s), 7.4–7.26 (3H, m), 7.39–7.42 (3H, m), 7.50–7.52 (2H, m),
7.83–7.85 (1H, m), 8.62 (1H, s). 13C NMR (CDCl3) ꢂ 21.3 (q),
127.3 (d), 127.5 (s), 128.9 (d), 129.0 (d), 129.1 (d), 129.2 (d),
129.6 (d), 130.4 (d), 137.8 (s), 138.1 (s), 139.0 (s). Calcd for
C16H13NTe: C, 55.40; H, 3.78; N, 4.04%. Found: C, 55.11; H,
3.62; N, 3.99%.
Reaction of Se-Alkenyl Selenocarbamate 4a with Hydroxyl-
amine-O-sulfonic Acid in the Presence of Allyltrimethylsilane.
An acetonitrile solution (10 mL) of crude Se-alkenyl selenocarba-
mate 4a (573 mg), obtained from the reaction of bis(N,N-diethyl-
carbamoyl) diselenide (10), NaBH4 and ynone 3 (366 mg, 2.50
mmol), was treated with hydroxylamine-O-sulfonic acid (673 mg,
2.4 mol amt.) at room temperature for 6 h in the presence of allyl-
trimethylsilane (2852 mg, 10 mol amt.). The reaction was quench-
7.28 (3H, m), 7.39–7.41 (2H, m); 13C NMR (CDCl3) ꢂ 15.5 (q),
126.8 (d), 127.5 (d), 127.6 (d), 129.3 (d), 140.0 (s), 153.0 (s),
157.3 (s); 125Te NMR (CDCl3) ꢂ 3806. Calcd for C10H9NOTe:
C, 41.88; H, 3.16; N, 4.88%. Found: C, 41.47; H, 3.16; N, 4.61%.
10b (R1 ¼ R2 ¼ C6H5): Yellow amorphous solids, mp 107.5–
108.0 ꢁC (dec.); MS (m=z) 351 (Mþ; 10%, 130Te), 349 (Mþ; 13%,
128Te), 347 (Mþ; 9%, 126Te), 335 (Mþ ꢂ O; 61%, 130Te), 333
(Mþ ꢂ O; 60%, 128Te), 331 (Mþ ꢂ O; 76%, 126Te), 102 (C6H5-
C2H; bp); IR (KBr) 1485, 1353, 1238, 1134, 1060, 756, 693
cmꢂ1 1H NMR (CDCl3) ꢂ 7.23–7.31 (7H, m), 7.36 (1H, s),
;
7.48–7.50 (2H, m), 7.58 (1H, s); 13C NMR (CDCl3) ꢂ 97.4 (d),
125.8 (d), 126.7 (d), 127.2 (d), 128.6 (d), 128.7 (d), 130.3 (s),
162.9 (s), 170.3 (s); 125Te NMR (CDCl3) ꢂ 3831. Calcd for

K. Shimada et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
575
ed by large amount of water, and the reaction mixture was extract-
ed with chloroform. The organic layer was washed with water and
was dried over anhydrous Na2SO4 powder. The organic solvent
was removed in vacuo, and the residual crude products were sub-
jected to column chromatography on silica gel to obtain isoselena-
zoles 6a (48 mg, 13%) and isoxazole 8a (125 mg, 35%) along with
several uncharacterizable products.
12g (R1 ¼ C6H5, R2 = n-C3H7, approximately 5:1 geometrical
mixture): Pale yellow oil; IR (oil) 2963, 2934, 2210, 1598, 1491,
1444, 1378, 1193, 1179, 1095 cmꢂ1; 1H NMR (CDCl3) major iso-
mer ꢂ 0.89–1.11 (3H, m), 1.47–1.83 (2H, m), 2.29–2.57 (2H, m),
2.43 (3H, s), 7.35–7.40 (7H, m), 7.83–7.97 (2H, m).
Preparation of Isoselenazoles 6 by Treating Oxime Tosy-
lates 12 with Sodiumhydrogen Selenide. An ethanolic solution
of NaBH4 (425 mg, 11 mmol) was treated with elemental selenium
(237 mg, 3.0 mmol) under an argon atmosphere at 0 ꢁC, and then,
ynone oxime tosylate 12 (2.2 mmol) was added to the colorless so-
lution. The reaction mixture was stirred at room temperature for
2 h. The reaction was quenched with a large amount of water,
and the reaction mixture was extracted with benzene. The organic
layer was washed with water and was dried over anhydrous
Na2SO4 powder. The solvent was removed in vacuo, and the re-
sidual crude products were subjected to column chromatography
on silica gel to obtain isoselenazoles 6 and isoxazoles 8. Excep-
tionally, in case the reaction starting from oxime tosylate 12b
(R1 ¼ R2 ¼ C6H5, 818 mg, 2.2 mmol), unexpected 1,2-diselenole
13b (304 mg, 38% yield) was obtained besides isoxazole 8b
(431 m, 59% yield).
Preparation of Isochalcogenazole 6a and 7a by Treating
Oxime Tosylates 12a with Bis(N,N-dimethylcarbamoyl) Di-
chalcogenide 1 and 2 with NaBH4. A methanolic solution
of bis(N,N-dimethylcarbamoyl) dichalcogenide (X ¼ Se, Te, 0.7
mmol) was treated with NaBH4 58 mg (2.2 mol amt.) or 116 mg
(4.4 mol amt.) under an argon atmosphere at ꢂ50 ꢁC for 15 min,
and then oxime tosylate 12a (488 mg, 2.20 mol amt.) was treated
with the resulting mixture at R.T. or 40 ꢁC for several hours.
The reaction was quenched with a large amount of water, and
the reaction mixture was extracted with benzene. The organic lay-
er was washed with water and was dried over anhydrous Na2SO4
powder. The solvent was removed in vacuo, and the residual crude
products were subjected to column chromatography on silica gel
to obtain isoselenazoles 6a or isotellurazole 7a in moderate yields.
In case the reaction starting from 2, oxime tosylate 15a was
obtained as the main byproduct.
Conversion of Ynones 3 into the Corresponding Ynone Ox-
ime Tosylates 12. A methanolic solution of ynone 3 (3.00 mmol)
was treated with a solution of hydroxylamine hydrochloride
(462 mg, 2.2 mol amt.) and sodium acetate (270 mg, 1.1 mol amt.)
in H2O/methanol at room temperature for 5 h. The reaction was
quenched by adding a large amount of water to the reaction mix-
ture, and the mixture was extracted with CH2Cl2. The organic
layer was washed twice with water and was dried over anhydrous
Na2SO4 powder. The organic solvent was removed in vacuo, and
the residual crude products were subjected to column chromatog-
raphy on silica gel to obtain a syn–anti geometrical mixture of
ynone oximes 11 (98% for 11a, 47% for 11b, and 50% for 11g,
respectively) as a main products as colorless powders or oils be-
sides isoxazole 8 as a byproduct. Subsequently, a CH2Cl2 solution
of 11 (9 mmol) was treated with p-toluenesulfonyl chloride (1891
mg, 1.1 mol amt.) and triethylamine (2001 mg, 2.2 mol amt.) at
room temperature for 24 h. The reaction was quenched with 10%
aqueous hydrochloric acid, and the reaction mixture was extracted
with CH2Cl2. The organic layer was washed with a saturated
aqueous NaHCO3 solution and was dried over anhydrous Na2SO4
powder. The solvent was removed in vacuo, and the residual crude
products were subjected to column chromatography on silica gel
to obtain the corresponding oxime tosylates 12 in high yields
(87% for 12a, 79% for 12b, and 84% for 12g, respectively). In
most cases, the major byproducts were the corresponding isoxa-
zoles 8.
11a (R1 ¼ C6H5, R2 ¼ CH3, approximately 10:1 geometrical
mixture): Pale yellow oil; IR (oil) 3261, 3059, 2922, 2218, 1616,
1327, 1184, 1172, 1028, 979, 756, 689 cmꢂ1 1H NMR (CDCl3)
;
major isomer ꢂ 2.21 (3H, s), 7.20–7.80 (5H, m), 8.60–9.20 (1H,
br s), minor isomer ꢂ 2.38 (3H, s), 7.20–7.80 (5H, m), 8.60–9.20
(1H, br s).
6g (R1 ¼ C6H5, R2 = n-C3H7): Red oil; MS (m=z) 251 (Mþ;
31%, 80Se), 102 (C6H5C=CH; bp); IR (oil) 2961, 1548, 1446,
758, 691 cmꢂ1; 1H NMR (CDCl3) ꢂ 0.97 (3H, t, J ¼ 7:3 Hz), 1.78
(2H, sextet, J ¼ 7:3 Hz), 2.75 (2H, t, J ¼ 7:3 Hz), 7.33–7.38 (3H,
m), 7.47–7.48 (2H, m), 7.67 (1H, br s); 13C NMR (CDCl3) ꢂ 13.9
(q), 22.0 (t), 37.9 (t), 122.3 (d), 126.9 (d), 129.1 (d), 129.3 (d),
133.6 (s), 172.2 (s), 175.9 (s). Calcd for C12H13NSe: C, 57.61;
H, 5.24; N, 5.60%. Found: C, 57.85; H, 5.29; N, 5.50%.
8b (R1 ¼ R2 ¼ C6H5): Colorless needles, mp 141.2–141.7 ꢁC
(lit.,64 141 ꢁC).
11b (R1 ¼ R2 ¼ C6H5): colorless oil; IR (oil) 3266, 2219,
1498, 1451, 1401, 1334, 1061, 956, 751, 689 cmꢂ1 1H NMR
;
(CDCl3) ꢂ 7.00–8.20 (10H, m), 9.20–9.50 (1H, m).
11g (R1 ¼ C6H5, R2 = n-C3H7, approximately 1:1 geometrical
mixture): IR (oil) 3322, 2966, 2876, 2215, 1491, 1443, 1314, 993,
757, 690 cmꢂ1; 1H NMR (CDCl3) ꢂ 1.00 (3H, t, J ¼ 6:9 Hz), 1.01
(3H, t, J ¼ 6:9 Hz), 1.40–1.90 (2H, m), 2.43 (2H, br t, J ¼ 7:0
Hz), 7.20–7.60 (3H, m), 7.70–8.00 (2H, m).
12a (R1 ¼ C6H5, R2 ¼ CH3, approximately 10:1 geometrical
mixture): Pale yellow powder, mp 69.7–70.1 ꢁC; IR (KBr) 3060,
2925, 2202, 1378, 1194, 1180, 817 cmꢂ1; 1H NMR (CDCl3) major
isomer ꢂ 2.20 (3H, s), 2.43 (3H, s), 7.20–7.40 (5H, m), 7.48 (2H,
br d, J ¼ 8:0 Hz), 7.92 (2H, br d, J ¼ 8:0 Hz), minor isomer ꢂ
2.14 (3H, s), 2.43 (3H, s), 7.20–7.40 (5H, m), 7.49 (2H, br d,
J ¼ 8:0 Hz), 7.93 (2H, br d, J ¼ 8:0 Hz); 13C NMR (CDCl3, major
isomer) ꢂ 18.3 (q), 20.8 (q), 21.6 (q), 95.1 (s), 120.6 (s), 128.4 (d),
128.5 (d) 128.77 (d), 128.82 (d), 129.6 (d), 132.0 (s), 132.2 (s),
145.3 (s), 151.7 (s). Calcd for C17H15NO3S: C, 65.16; H, 4.82;
N, 4.47%. Found: C, 65.01; H, 4.88; N, 4.45%.
8g (R1 ¼ C6H5, R2 = n-C3H7):41,65 Pale yellow solids, IR
(KBr) 3059, 2961, 1575, 1452, 1072, 893 cmꢂ1; 1H NMR (CDCl3)
ꢂ 1.21 (3H, t, J ¼ 6:8 Hz), 1.40–2.00 (2H, m), 2.20–2.80 (2H, m),
6.39 (1H, s), 7.30–7.80 (5H, m).
13b (R1 ¼ R2 ¼ C6H5): Red prisms, mp 127.4–127.7 ꢁC; MS
(m=z) 365 (Mþ; 26%, 80Se), 363 (Mþ; 21%, 78Se), 102 (bp); IR
;
(KBr) 1548, 1479, 1443, 1150, 823, 757, 695 cmꢂ1 1H NMR
(CDCl3) ꢂ 7.10–7.76 (11H, m); 13C NMR (CDCl3) ꢂ 118.9 (s),
125.4 (d), 126.7 (d), 126.9 (d), 129.1 (d), 130.0 (d), 130.3 (d),
135.4 (s), 153.2 (a), 159.4 (a), 171.2 (s); 77Se NMR (CDCl3) ꢂ
459.4 (s), 569.0 (s). Calcd for C15H11NSe2: C, 49.61; H, 3.05;
N, 3.86%. Found: C, 49.61; H, 3.00; N, 3.70%.
15a (R1 ¼ C6H5, R2 ¼ CH3): Orange powder, mp 115.2–117.3
ꢁC; MS (m=z) 273 (Mþ ꢂ Me2NCO ꢂ OTs; 2%, 130Te), 271
(Mþ ꢂ Me2NCO ꢂ OTs; 2%, 128Te), 269 (Mþ ꢂ Me2NCO ꢂ
12b (R1 ¼ R2 ¼ C6H5, approximately 10:1 geometrical mix-
ture: Pale yellow solid, mp 99.1–100.9 ꢁC; IR (KBr) 3064, 2206,
1760, 1380, 1194, 1179, 766, 691 cmꢂ1; 1H NMR (CDCl3) ꢂ 2.50
(3H, s), 7.20–7.80 (12H, m), 8.00–8.30 (2H, m).

576 Bull. Chem. Soc. Jpn. Vol. 80, No. 3 (2007)
Isochalcogenazole
Table 6. Bond Lengths, Bond Angles, and Torsion Angles for 1,2-Diselenole 13b
˚
Bond lengths/A
Bond angles/deg
Se(2)–Se(1)–C(3)
Torsion angles/degaÞ
Se(1)–Se(2)–C(1)–N(4) 172.6(4)
Se(1)–Se(2)
2.3225(8)
1.887(5)
1.943(5)
1.276(4)
1.421(6)
1.49(7)
91.6(2)
92.6(2)
Se(1)–C(3)
Se(2)–C(1)
N(4)–C(1)
N(4)–C(5)
C(1)–C(2)
C(2)–C(3)
C(3)–C(11)
C(5)–C(6)
C(5)–C(10)
C(11)–C(12)
C(11)–C(16)
Se(1)–Se(2)–C(1)
C(1)–N(4)–C(5)
Se(2)–C(1)–N(4)
Se(2)–C(1)–C(2)
N(4)–C(1)–C(2)
C(1)–C(2)–C(3)
Se(1)–C(3)–C(2)
Se(1)–C(3)–C(11)
C(2)–C(3)–C(11)
N(4)–C(5)–C(6)
N(4)–C(5)–C(10)
Se(1)–Se(2)–C(1)–C(2)
Se(1)–C(3)–C(2)–C(1)
Se(1)–C(3)–C(11)–C(12)
Se(1)–C(3)–C(11)–C(16)
Se(2)–Se(1)–C(3)–C(2)
Se(2)–Se(1)–C(3)–C(11)
Se(2)–C(1)–N(4)–C(5)
Se(2)–C(1)–C(2)–C(3)
N(4)–C(1)–C(2)–C(3)
N(4)–C(5)–C(6)–C(7)
N(4)–C(5)–C(10)–C(9)
C(1)–Se(2)–Se(1)–C(3)
C(1)–N(4)–C(5)–C(6)
C(1)–N(4)–C(5)–C(10)
C(1)–C(2)–C(3)–C(11)
C(2)–C(1)–N(4)–C(5)
C(2)–C(3)–C(11)–C(12)
C(2)–C(3)–C(11)–C(16)
ꢂ3:8ð4Þ
ꢂ3:4ð7Þ
34.1(6)
ꢂ144:5ð4Þ
0.1(4)
179.6(4)
2.3(7)
5.2(7)
ꢂ171:4ð5Þ
ꢂ178:7ð5Þ
179.0(5)
1.9(2)
ꢂ131:7ð5Þ
51.8(7)
177.2(5)
178.4(5)
ꢂ146:5ð5Þ
34.9(8)
121.0(4)
125.2(4)
112.7(3)
122.0(4)
124.2(4)
118.7(4)
116.4(4)
124.9(5)
118.0(5)
122.9(5)
1.339(7)
1.473(7)
1.377(7)
1.400(7)
1.392(7)
1.396(7)
a) The sign is positive if when looking from atom 2 to atom 3 a clockwise motion of atom 1 would superimpose
it on atom 4.
OTs; 1%, 126Te), 102 (bp); IR (KBr) 2924, 1662, 1596, 1378,
1364, 1189, 1174, 1083, 803, 788, 667 cmꢂ1
;
1H NMR (CDCl3)
References
ꢂ 2.08 (3H, s), 2.32 (3H, s), 2.68 (3H, s), 2.77 (3H, s), 6.66
(1H, s), 7.02–7.36 (5H, m), 7.43–7.45 (2H, m), 7.74–7.79 (2H,
m); 13C NMR (CDCl3) ꢂ 19.6 (q), 21.6 (q), 35.7 (q), 38.3 (q),
128.1 (d), 128.5 (d), 128.6 (d), 128.8 (d), 129.45 (s), 129.48 (d),
132.7 (s), 133.6 (d), 143.0 (s), 144.8 (s), 155.9 (s), 164.0 (s). Calcd
for C20H22N2O4STe: C, 46.73; H, 4.31; N, 5.45%. Found: C,
47.05; H, 4.50; N, 5.41%.
1
9, 789.
2
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5
6
˚
ing graphite-monochromated Mo Kꢃ radiation (ꢄ ¼ 0:71069 A).
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7
ꢁ
3
˚
˚
26:989ð2Þ A, ꢀ ¼ 96:52ð1Þ , V ¼ 1336:1ð8Þ A , space group =
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the final R ¼ ꢀjjFoj ꢂ jFcjj=ꢀFoj value of 0.046 and Rw
¼
2
1=2
2
½ðꢀwðjFoj ꢂ jFcjÞ =ꢀwFo Þꢄ of 0.044. The maximum and min-
imum peaks on the final difference Fourier map correspond to
0.28 and ꢂ0:31 eAꢂ3, respectively. Selected bond lengths and
˚
bond angles are listed in Table 6.
This work was partially supported by Grant-in-Aid
(No. 14044006) from the Ministry of Education, Culture,
Sports, Science and Technology. We thank Ms. Yoriko
Fujisawa in Iwate University for the elemental analysis
measurement.
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