Selenium-containing heterocycles from isoselenocyanates: Synthesis of 1,3-selenazoles from N-phenylimidoyl isoselenocyanates

Article abstract of DOI:10.1002/1522-2675(20000705)83:7<1576::AID-HLCA1576>3.0.CO;2-M

The reaction of N-phenylbenzamides 5 with excess SOCl₂ under reflux gave N-phenylbenzimidoyl chlorides 6, which, on treatment with KSeCN in acetone, yielded imidoyl isoselenocyanates of type 2. These products, obtained in almost quantitative yield, were stable in the crystalline state. They were transformed into selenourea derivatives 7 by the reaction with NH₃, or primary or secondary amines. In acetone at room temperature, 7 reacted with activated bromomethylene compounds such as 2-bromoacetates, acetamides, and acetonitriles, as well as phenacyl bromides and 4-cyanobenzyl bromide to to give 1,3-selenazol-2-amines of type 9 (Scheme 2). A reaction mechanism via alkylation of the Se-atom of 7, followed by ring closure and elimination of aniline, is most likely (cf. Scheme 7). In the case of selenourea derivatives 7d and 7I with an unsubstituted NH₂ group, an alternative ring closure via elimination of H₂O led to 1,3-selenazoles 10a and 10b, respectively (Schemes 4 and 7). On treatment with NaOH, ethyl 1,3- selenazole-5-carboxylates 9I and 9s were saponified and decarboxylated to give the corresponding 5-unsubstituted 1,3-selenazoles 12a and 12b (Scheme 6). The molecular structures of selenourea 7f and the 1,3-selenazoles 9c and 9d have been established by X-ray crystallography (Figs. 1 and 3).

Full text of DOI:10.1002/1522-2675(20000705)83:7<1576::AID-HLCA1576>3.0.CO;2-M

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Helvetica Chimica Acta ± Vol. 83 (2000)
Selenium-Containing Heterocycles from Isoselenocyanates: Synthesis of
1,3-Selenazoles from N-Phenylimidoyl Isoselenocyanates
by Yuehui Zhou1), Anthony Linden, and Heinz Heimgartner*
Organisch-chemisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich
Dedicated to Prof. Dr. Manfred Hesse on the occasion of his 65th birthday
The reaction of N-phenylbenzamides 5 with excess SOCl2 under reflux gave N-phenylbenzimidoyl chlorides
6, which, on treatment with KSeCN in acetone, yielded imidoyl isoselenocyanates of type 2. These products,
obtained in almost quantitative yield, were stable in the crystalline state. They were transformed into selenourea
derivatives 7 by the reaction with NH3, or primary or secondary amines. In acetone at room temperature, 7
reacted with activated bromomethylene compounds such as 2-bromoacetates, acetamides, and acetonitriles, as
well as phenacyl bromides and 4-cyanobenzyl bromide to to give 1,3-selenazol-2-amines of type 9 (Scheme 2). A
reaction mechanism via alkylation of the Se-atom of 7, followed by ring closure and elimination of aniline, is
most likely (cf. Scheme 7). In the case of selenourea derivatives 7d and 7l with an unsubstituted NH2 group, an
alternative ring closure via elimination of H2O led to 1,3-selenazoles 10a and 10b, respectively (Schemes 4 and
7). On treatment with NaOH, ethyl 1,3-selenazole-5-carboxylates 9l and 9s were saponified and decarboxylated
to give the corresponding 5-unsubstituted 1,3-selenazoles 12a and 12b (Scheme 6). The molecular structures of
selenourea 7f and the 1,3-selenazoles 9c and 9d have been established by X-ray crystallography (Figs. 1 and 3).
1. Introduction. ± With the aim of using less-toxic selenium compounds for the
synthesis of selenaheterocycles, we have prepared arenecarbonyl isoselenocyanates 1
from KSeCN and arenecarbonyl chlorides as precursors [1]. These transient
intermediates could not be isolated, because they readily oligomerized to give a
mixture of oligomers. This is the reason for low yields of products from reactions with
these intermediates, e.g., the formation of selenourea derivatives [1][2]. In our previous
paper, we have shown that the in situ generated arenecarbonyl isoselenocyanates 1 can
be trapped by ethyl diazoacetate, leading to 1,2,3-selenadiazole derivatives via a 1,3-
dipolar cycloaddition [1].
Surprisingly, the relatively stable N-phenylimidoyl isoselenocyanates 2 (Arˆ Ph),
which can be conveniently prepared from N-phenylimidoyl chlorides and KSeCN, have
been only rarely investigated. To the best of our knowledge, there is only one report on
1
)
Postdoctoral stay at the University of Zürich (August 1998± December 1999). Present address: Depart-
ment of Chemistry, Syracuse University, Syracuse, NY 13244, USA.

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these heterocumulenes, which seem to be attractive synthons for Se-containing
compounds. Kirsanova and Derkach described, e.g., the reaction of 2 (Arˆ Ph, R ˆ H)
with aniline in which the corresponding selenourea derivative was formed [3].
On the other hand, the synthesis of 1,3-selenazoles is still an attractive goal. The
known syntheses rely mainly on the Hantzsch reaction [4] (cf. Scheme 1). They require
selenoureas or selenoamides that, in turn, have to be prepared by treatment of
cyanamides and nitriles, respectively, with H2Se [5]. Compared with H2S, H2Se is more
toxic and more difficult to handle [6]. But the search for alternative syntheses of 1,3-
selenazoles was rarely successful, in contrast to those of analogous 1,3-thiazoles. For
example, a convenient method for the preparation of 1,3-thiazoles from a-thiocyanato-
acetophenones and primary amines, which does not involve H2S [7], was shown to be
unusable for the synthesis of 1,3-selenazoles [8]. In a recent re-investigation of these
experiments, the formation of a series of acyclic arenecarbonylcarboselenoamides has
been observed, but no 1,3-selenazole could be detected [9]. Some special 1,3-
selenazoles, e.g., those unsubstituted at C(2), are accessible in moderate yield by the
reaction between isocyanides with an acidic H-atom in a-position and isoselenocya-
nates [10]. Another useful starting material for the preparation of 1,3-selenazoles
proved to be allenyl isoselenocyanate, which was obtained from propynyl selenocya-
nate by a [3.3]-sigmatropic rearrangement [11].
The synthesis of selenoureas and selenoamides, which are both potential precursors
of 1,3-selenazoles, has been investigated by several groups with the aim of avoiding
H2Se. For example, Hartmann explored a synthesis of N,N-dialkylselenoamides by
treating corresponding S-alkylated thioamides with Na2Se, which was generated in situ
from elemental Se and Na in DMF [12]. Analogously, tri- and tetrasubstituted
thioureas were transformed into the corresponding selenoureas [13]. The overall
reaction is a conversion of a CˆS to a CˆSe group. In a similar reaction, the
transformation of a CˆO into a CˆS group was achieved by using chloroimidates, and
Na2Se [14] or chloroiminium salts2) and NaHSe [15]. A possibly rather general
selenating reagent for the conversion of CˆO into CˆSe groups is phenylphospho-
noselenoic dichloride [16]. The reagent was readily prepared by the reaction of
dichlorophenylphosphine with an excess of powdered Se at 170 ± 1758 in an inert
atmosphere. The main drawback of earlier protocols for the selenation of carbonyl
groups with P2Se5 was the low yield of product [17]. Lai and Reid reacted
arenecarbonitriles with NaHSe and obtained selenoamides in high yield [18], and
Ruan et al. generated NaHSe for the same purpose in situ from Se and NaBH4 [19].
A useful approach to selenoureas is the reaction of isoselenocyanates with amines
[20]. As a rule, aryl and alkyl isoselenocyanates are more difficult to synthesize than
arenecarbonyl analogues. Whereas the preparation of the former needs two or more
reaction steps [21], the latter can be easily synthesized by the reaction of arenecarbonyl
chlorides with KSeCN [22] (cf. [1]).
Although N-(arylcarbonyl)selenoureas are easily accessible, they have not been
used to synthesize 1,3-selenazoles according to the traditional Hantzsch reaction, until
Liebscher and Hartmann modified the procedure [23] (Scheme 1). In the classical
2
)
The chloroimidates and chloroiminium salts can be prepared conveniently by treatment of the
corresponding amides with phosgene.

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Helvetica Chimica Acta ± Vol. 83 (2000)
Hantzsch selenazole synthesis, the ring closure of the alkylated intermediate A occurs
between the NH2 group and the CˆO group of the former a-bromocarbonyl compound
to give B. On the other hand, the N-acylated intermediate C, on treatment with Et3N,
cyclizes via intramolecular nucleophilic attack of the activated CH2 group onto the acyl
C-atom to give D. Elimination of H2O from B and D leads to the 1,3-selenazoles 3a and
3b, respectively. Later, this concept was extended to N-(phenylimidoyl)thioureas [24],
N-(aminomethylene)thioureas [25], and N-(diaminomethylene)thioureas [26] for the
synthesis of 1,3-thiazoles, to 2-aminovinyl selenoketones for preparing selenophenes
and selenopyrones [27], and to N-(selenoacyl)carboximidamides (N-(selenoacyl)ami-
dines) to synthesize 1,3-selenazoles [28]. In these cases, an amine molecule was
eliminated after the cyclization step. However, in the preparation of N-(selenoacyl)-
carboximidamide H2Se is again needed as the source of Se. Based on the same concept,
N,N-dimethyl-N'-[(dimethylamino)(selenocarbonyl)]formimidamide was also used as
a starting material in the synthesis of 1,3-selenazoles [29]. The starting material itself
was prepared by an elegant carbene reaction with elemental Se.
Scheme 1
In the present paper, we describe a new modification of the Liebscher-Hartmann
synthesis [23] of 1,3-selenazoles from N-(N-phenylimidoyl)selenoureas, which leads to
the products in high yield and purity. Unlike (arenecarbonyl)selenoureas 4, which were

Helvetica Chimica Acta ± Vol. 83 (2000)
1579
synthesized from transient arenecarbonyl isoselenocyanates 1 and amines in low yield
(cf. [1]), (N-phenylimidoyl)selenoureas of type 7 (cf. Scheme 2) were prepared from
stable N-phenylimidoyl isoselenocyanates 2. The latter are easily accessible from N-
phenylimidoyl chlorides 6 and KSeCN.
2. Results and Discussion. ± A mixture of an N-phenylbenzamide of type 5
(Scheme 2) and 2 ± 3 equiv. of SOCl2 was heated to reflux until the evolution of SO2
ceased. The excess SOCl2 was evaporated, and the crude imidoyl chloride 6, obtained as
a white solid, was dried under vacuum for 24 h3). To this material, a freshly prepared
solution of KSeCN4) in dry acetone was added, and the mixture was stirred at room
temperature. After 30 min, the mixture was poured into ice-water, the precipitate was
filtered and air-dried, and identified as imidoyl isoselenocyanate of type 2. The yield
was almost quantitative and the product was analytically pure without recrystallization.
Compounds 2a ± c were rather stable at room temperature in the solid state but
decomposed slowly in CDCl3 and other organic solvents5). Nevertheless, it is
recommended to store the products in the refrigerator.
Scheme 2
In the IR spectra (KBr) of 2a ± c, a strong absorption band at 1985 ± 2053 cmÀ1 was characteristic for the
isoselenocyanate structure as was the singlet at 138.9 ± 140.1 ppm in the 13C-NMR spectrum (CDCl3).
‡
Furthermore, the compounds showed correct elemental analyses and intense peaks for [M ‡ 1] (CI-MS) and
.
‡
M
(EI-MS).
3
)
It is important to remove all SOCl2 to achieve high yields of pure product in the following reaction.
KSeCN was prepared from elemental Se and KCN in EtOH solution and dried at ca. 1208.
In EtOH solution, Se precipitated on standing overnight at room temperature.
4
)
5
)

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Table 1. Yields of Isoselenocyanates 2 and Selenoureas 7
Compound
R1
R2
R3
Yield [%]
2a
b
c
7a
b
c
d
e
f
g
h
i
H
±
±
±
99
99
98
92
74
80
65
8
85
60
95
85
82
97
75
92
Me
Cl
H
H
H
À(CH2)2O(CH2)2À
À(CH2)4À
À(CH2)5À
H
H
H
Me
H
Ph
4
Me
Me
Me
Me
Cl
Cl
Cl
Cl
À(CH2)2O(CH2)2À
À(CH2)2O(CH2)2À
H
H
Me
H
PhCH2
Ph
j
k
l
Bu
H
Me
Bu
H
Ph
m
Treatment of solutions of 2a ± c in acetone with aqueous NH3 (25%), primary or
secondary amines at room temperature gave selenourea derivatives of type 7 in good-
to-excellent yields (Table 1). In general, the reaction was fast, and after 5 ± 30 min the
starting material had disappeared (TLC). Whereas, with aliphatic amines, the reaction
was smooth, yielding only one product, it was slower with N-methylaniline. In the latter
case, the mixture showed several spots on TLC along with the main spot for 76). The
lowest yields (60 ± 75%) were obtained from the reactions with NH3.
The structures of the selenourea derivatives of type 7 have been deduced from their
spectral and analytical data, and, in the case of 7f, the structure has been established by
X-ray crystal-structure analysis (Fig. 1).
The crystal structure of 7f shows that there is no conjugation between the p-systems
of the molecule. Both phenyl rings, as well as the Se, C(1), N(5) plane, are twisted out of
the plane formed by the atoms C(1), N(2), C(3), N(4), C(11), and C(18): this latter
plane forms an angle of ca. 508 with that defined by Se, C(1), and N(5), and the torsion
angles N(2)ÀC(3)ÀC(11)ÀC(16) and C(3)ÀN(4)ÀC(18)ÀC(19) are 35.7(4) and
35.8(4)8, respectively. The amidine HÀN(4) forms an intermolecular H-bond with the
Se-atom of a neighboring molecule. These interactions link the molecule into infinite
one-dimensional chains that run parallel to the z-axis and have a graph set motif [31] of
C(6).
In all cases in which the terminal urea N-atom of the selenourea bears one or two
aliphatic substituents or is unsubstituted, there exists only one tautomer in CDCl3
solution, as shown by NMR spectroscopy. On the other hand, two tautomers have
been detected in the cases of 7e, 7i, and 7m, i.e., where a Me(Ph)N group is present.
As the crystal structure of 7f showed that the NH is the terminal group of the
amidine structure, we expected that the same tautomer would be present in
6
)
Reactions with aniline were even more sluggish and led to complex mixtures and only low yields of the
corresponding selenoureas.

Helvetica Chimica Acta ± Vol. 83 (2000)
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Fig. 1. ORTEP Plot [30] of the molecular structure of 7f (with 50% probability ellipsoids; arbitrary numbering
of the atoms)
CDCl3 solution. Indeed, this was established by 1H- and 13C-COSY and HSQC
and 15N-HMBC experiments, from which the chemical shifts of all H-, C-, and
N-atoms of 7f could be assigned (Fig. 2,a). The position of the movable H-atom
was determined by HMBC and 15N-HMBC experiments, which correlated the
H-atom (d 11.5 ppm) of the NH group (d(N) ˆ À254 ppm (d)) with the C-atoms
at d 132.1 (s) and 123.0 ppm (d), respectively, and the aromatic H-atom at d 7.04 ppm
with the N-atom of the NH group (3J couplings). Therefore, the compounds 7
are N2-[(amino)(selenocarbonyl)]-N1-phenylarenecarboximidamides with a similar
structure as some selenazadienes, which were used in hetero-Diels-Alder reactions (cf.
[28][32]).
In the cases of selenoureas synthesized with N-methylaniline, i.e., compounds 7e, 7i,
and 7m, two tautomers in a ratio of ca. 1:3 to 1:4 were present in CDCl3 solution

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Fig. 2. Assignment of chemical shifts of the H-, C-, and N-atoms of a) 7f, b) 7i, and c) 7i'
(NMR)7). For example, the 1H-NMR spectrum of 7i shows two signals for MeN (d 3.84
and 3.69, ratio 3 :1) and two for an aromatic Me group (d 2.37 and 2.26 ppm, ratio 1:3)
for the tautomers 7i and 7i' (Scheme 3). In 7i, the CˆSe group is conjugated with the 4-
methylphenyl ring and, as a result of the electron-withdrawing effect, the chemical shift
of the aromatic Me group is shifted to lower field compared with 7i'. On the other hand,
the signal of the MeN group of 7i appears at higher field than in 7i', because the
interaction of the N electron pair with CˆSe is weakened by the conjugation of CˆSe
with the 4-methylphenyl ring. Based on this analysis, we propose that 7i' is the major
7
)
We expected that one of the tautomers has a structure analogous to 7f. Unfortunately, the correlation of
NH with the C-atoms could not be observed in this case because of the rapid exchange between the
tautomers. However, the 1H-NMR spectrum allowed the decision which of the tautomers has the analogous
structure to 7f.

Helvetica Chimica Acta ± Vol. 83 (2000)
1583
tautomer. The results of additional NMR studies supported this conclusion: by means
1
of H- and 13C-COSY, HSQC, HMBC, and 15N-HMBC experiments, the assignment of
the H- and C-atoms of both tautomers 7i and 7i' was possible (Fig. 2,b). Based on the
comparison of the spectra with those of 7f, it was concluded that 7i is the minor and 7i'
the major compound.
Scheme 3
In analogy to 7i/7i', we propose that, in 7e and 7m, the major tautomer is that in
which CˆSe is not conjugated with the benzamidine ring, i.e., with the MeN signal at
lower field (d 3.81 (7e') and 3.65 (7e); d 3.82 (7m') and 3.65 (7m)). In accordance with
this assignment, the NH of the major tautomer absorbs at higher field (d 10.8, 10.9, and
11.1 ppm for 7e', 7i', and 7m', resp., and d 12.4, 12.4, and 12.7 ppm for 7e, 7i, and 7m,
resp.).
The N,N-disubstituted selenoureas of type 7, i.e., those with R2, R3=H, reacted with
a-bromoesters, amides, and nitriles, as well as with bromomethyl aryl ketones in
acetone at room temperature to give the corresponding salts of type 8. The reaction was
complete after a few minutes. Even 4-(bromomethyl)benzonitrile reacted under the
same conditions with 7i/7i'. Treatment of the crude material with a small excess of Et3N
or NaH gave 1,3-selenazoles 9 via elimination of aniline as white or yellowish solids in
high yields (Scheme 2 and Table 2)8). According to NMR spectroscopy, the precipi-
tated products were already pure, but, for characterization and elemental analysis, they
were recrystallized from EtOH, Et2O, or acetone.
The structures of 1,3-selenazoles 9a ± t were elucidated by means of their spectral
data and elemental analyses, and, in the cases of 9c and 9d, they have been established
by X-ray crystal-structure determination (Fig. 3). The two structures are very similar.
In both cases, the 1,3-selenazole ring is planar, but none of the phenyl rings is coplanar
with the five-membered ring.
The reaction of selenoureas with an NH2 group, e.g., 7d and 7l, with bromomethyl 4-
nitrophenyl ketone in boiling acetone yielded a precipitate that we believe was a
selenazolium salt. After trituration of the solid material with 5% aqueous NaOH
solution, 1,3-selenazoles 10a and 10b, respectively, with unsubstituted C(5) were
obtained (Scheme 4). The elemental analyses, as well as the mass spectra, showed that
H2O had been eliminated during cyclization, and the IR spectra indicated the absence
8
)
The 1,3-selenazoles 9 can also be prepared by a one-pot reaction starting with isoselenocyanates 2 in
acetone and successive addition of HNR2R3 and BrCH2Z.

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Table 2. Yields of 1,3-Selenazoles 9
Compound
R1
R2
R3
Z
Yield [%]
9a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
H
H
H
H
H
H
H
H
Me
Me
Me
Me
Me
Me
Cl
Cl
Cl
Cl
Cl
Cl
Cl
À(CH2)2O(CH2)2À
4-NO2ÀC6H4CO
4-NO2ÀC6H4CO
4-NO2ÀC6H4CO
4-MeOÀC6H4CO
EtOCO
EtOCO
EtOCO
CN
PhCO
90
97
95
98
88
80
79
8
96
95
81
85
90
86
95
92
99
94
85
96
95
À(CH2)4À
À(CH2)5À
Me
Ph
À(CH2)2O(CH2)2À
À(CH2)4À
Me
Me
Ph
Ph
5
À(CH2)2O(CH2)2À
À(CH2)2O(CH2)2À
À(CH2)2O(CH2)2À
À(CH2)2O(CH2)2À
4-NO2ÀC6H4CO
H2NCO
EtOCO
CN
Me
Me
Ph
Ph
4-NCÀC6H4
4-NO2ÀC6H4CO
4-NO2ÀC6H4CO
4-NO2ÀC6H4CO
EtOCO
EtOCO
EtOCO
CN
À(CH2)2O(CH2)2À
Bu
Me
Bu
Me
Bu
Ph
Bu
Ph
s
t
u
À(CH2)2O(CH2)2À
À(CH2)2O(CH2)2À
of a CˆO group. The NMR spectra showed that 10a and 10b, similarly as in the cases of
7e, 7i, and 7m, each exist in CDCl3 as a mixture of two tautomers in the ratio of ca. 5 :1.
In most cases, treatment of the amidinium (ˆ imidamidium) salts 8 (R2,R3 ˆ H)
with Et3N led smoothly to 1,3-selenazoles 9, but, in some experiments, the
deprotonated intermediates 11 were isolated as stable products (Scheme 5 and
Table 3). These N-(imidoyl)isoselenourea derivatives were fully characterized. They
were cyclized to give 1,3-selenazoles 9 by treatment with NaH in dry acetone. As an
exception, 11f could not be cyclized, probably because of the weak acidity of the CH2
group.
Scheme 4

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Fig. 3. ORTEP Plots [30] of the molecular structure of a) 9c and b) 9d (with 50% probability ellipsoids; arbitrary
numbering of the atoms)

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Scheme 5
Table 3. Yields of Isoselenoureas 11
Compound
R1
R2
R3
Z
Yield [%]
11a
b
c
d
e
H
H
Me
Me
Cl
À(CH2)2O(CH2)2À
EtOCO
CN
4-NCÀC6H4
4-NCÀC6H4
EtOCO
NCÀCH2
94
95
92
94
87
85
Me
Me
Ph
Ph
À(CH2)2O(CH2)2À
À(CH2)2O(CH2)2À
Me
f
Me
Ph
Scheme 6
1,3-Selenazoles of type 9 with an EtOCO group at C(5), e.g., 9l and 9s, after
saponification with 5% NaOH solution under reflux, decarboxylated smoothly to give
the corresponding 1,3-selenazoles 12a and 12b, respectively, with a free C(5) position
(Scheme 6).
It is well-known that C(5) in 1,3-thiazoles possess a high electron density. Therefore,
reactions with electrophiles such as aromatic diazonium salts, squaric acid, and
Vilsmeier reagent [33] occur at C(5), yielding diazo dyes and other useful fine chemicals.
In contrast, very few 1,3-selenazoles with a free C(5) position are known to date, and
the reactivity of these compounds at the unsubstituted C(5) is still not clear. Though
Bulka and Ahlers were successful in preparing diazo dyes from 2-(arylamino)-4-phenyl-
1,3-selenazoles and aromatic diazonium salts [34] and Keil and Hartmann in their
recent work prepared squarin dyes from 2,4-disubstituted 1,3-selenazoles [35], the
chemical shifts of HÀC(5) (selenazole moiety) of 12a (7.29 ppm) and 12b (7.18ppm)
indicate that the electron density is lower than in the analogous 1,3-thiazoles. For

Helvetica Chimica Acta ± Vol. 83 (2000)
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example, HÀC(5) (selenazole moiety) of 4-[4-(4-nitrophenyl)-1,3-thiazol-2-yl]mor-
pholine absorbs at 6.94 ppm [7b] and that of 4-(4-phenyl-1,3-thiazol-2-yl)morpholine
at 6.78ppm [36].
The formations of 1,3-selenazoles 9 and 10, respectively, via different ring-closure
processes need a comment. Whereas compounds 9 were obtained from N,N-
disubstituted selenourea derivatives (R2, R3=H), 1,3-selenazoles 10 were the only
observed products when N,N-unsubstituted 7 (R2 ˆ R3 ˆ H) were used in the reaction
with activated bromomethylene compounds. In both cases, the first step of the reaction
is the alkylation of the Se-atom leading to intermediate 8 (Schemes 2 and 7). With R2,
R3=H, the formation of the five-membered ring occurs via C-attack of the enolate onto
the amidinium (imidamidium) group of E to give F (Scheme 7). Elimination of aniline
then yields 9. In the case of R2 ˆ R3 ˆ H, an alternative cyclization to a five-membered
ring via nucleophilic attack of NH2 in 8' onto the CˆO group leads to intermediate G
and, after elimination of H2O, to 1,3-selenazoles 10 (Scheme 7). The cyclization to F
corresponds to that in the Liebscher-Hartmann synthesis whereas the ring closure to G
proceeds as in the classical Hantzsch synthesis (Scheme 1).
Scheme 7

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In conclusion, 4-aryl-1,3-selenazol-2-amines 9 with an electron-withdrawing group
at C(5) are conveniently accessible via the reaction of selenourea derivatives of type 7
with activated bromomethylene compounds. The selenourea derivatives 7 are easily
obtained from the reaction of benzimidoyl chlorides 6 and KSeCN, leading to
benzimidoyl isoselenocyanates 2, which on treatment with NH3 or amines give 7. As N-
phenylbenzamides are the starting materials for the preparation of 6, and KSeCN is
smoothly prepared from elemental Se and KCN in EtOH, the described synthesis of
1,3-selenazoles 9 is cheap and safe as no highly toxic Se-compounds are used. A further
advantage of the presented synthesis of 1,3-selenazole derivatives is the possibility of a
one-pot reaction starting with N-phenylimidoyl isoselenocyanates 2. The derivatives of
type 9 were obtained in 80 ± 95% yield.
We thank the analytical units of our institute for spectra and analyses, especially Mr. M. Binder for
performing numerous NMR experiments. Financial support of this work by the Dr. Helmut LegerlotzStiftung
and F. Hoffmann-La Roche AG, Basel, is gratefully acknowledged.
Experimental Part
1. General. See [1]. Atom numbering for the NMR data refer to the 1,3-selenazole moiety.
2. Preparation of N-Phenylbenzimidoyl Isoselenocyanates 2: General Procedure. A mixture of a N-
phenylbenzamide of type 5 and 2 ± 3 equiv. SOCl2 was heated to reflux for 2 ± 3 h, until the evolution of SO2
ceased. Excess SOCl2 was evaporated, and the corresponding N-phenylbenzimidoyl chloride 6 was obtained as a
white solid, which was dried in vacuo for 24 h. A freshly prepared soln. of KSeCN9) in acetone was added to 6
under stirring. Shortly after all of 6 had been dissolved, the yellowish benzimidoyl isoselenocyanate 2
crystallized from the soln. (in case of R1 ˆ Me or Cl). The mixture was poured on ice/H2O under stirring, and the
product was filtered by suction and air-dried.
N-Phenylbenzimidoyl Isoselenocyanate (2a). From 100.5 mmol of N-phenylbenzamide: 28.4 g (99%).
Yellowish crystals. M.p. 59 ± 608 (H2O). IR: 3054w, 2105m, 2079s, 2053s, 1610s, 1589m, 1575m, 1481m, 1446m,
1311w, 1265m, 1206m, 1176m, 1072w, 1050m, 1022m. 1H-NMR: 8.09 (d-like, 2 arom. H); 7.58± 7.38
(m, 5 arom. H); 7.25 (t-like, 1 arom. H); 7.03 (d-like, 2 arom. H). 13C-NMR: 148.0, 140.1 (2s, 2 arom. C);
‡
139.3 (s, NCSe); 132.5 (s, CN2); 132.3, 129.0, 128.7, 128.2, 125.6, 121.0 (6d, 10 arom. C). CI-MS: 287 ([M ‡ 1] ).
Anal. calc. for C14H10N2Se (285.21): C 58.95, H 3.51, N 9.82; found: C 58.80, H 3.55, N 9.81.
4-Methyl-N-phenylbenzimidoyl Isoselenocyanate (2b). From 162.5 mmol of 4-methyl-N-phenylbenzamide:
48.0 g (99%). Yellowish crystals. M.p. 103 ± 103.58 (acetone). IR: 3053w, 2919w, 2092m, 1991s, 1657w, 1610s,
1591s, 1571m, 1508m, 1278s, 1202s, 1179s, 1170m, 1114w, 1074w, 1047s, 1016m. 1H-NMR: 7.96 (AA' of AA'BB',
J ˆ 8.3, 2 arom. H); 7.39 (t-like, 2 arom. H); 7.29 ± 7.19 (m, 3 arom. H); 7.02 (d-like, 2 arom. H); 2.42 (s, Me).
13C-NMR: 148.1, 143.0, 140.1 (3s, 3 arom. C); 138.9 (s, NCSe); 129.8( s, CN2); 129.4, 129.0, 128.1, 125.4, 121.0
‡
(5d, 9 arom. C); 21.5 (q, Me). CI-MS: 301 ([M ‡ 1] ). Anal. calc. for C15H12N2Se (299.24): C 60.20, H 4.01,
N 9.36; found: C 60.13, H 4.06, N 9.36.
4-Chloro-N-phenylbenzimidoyl Isoselenocyanate (2c). From 100.7 mmol of 4-chloro-N-phenylbenzamide:
31.5 g (98%). Yellowish crystals. M.p. 92 ± 92.58 (Et2O). IR: 3064w, 2102w, 1986s, 1654w, 1610s, 1591s, 1568m,
1486m, 1448m, 1401m, 1300w, 1278s, 1206s, 1172m, 1106w, 1090s, 1072m, 1051m, 1012m. 1H-NMR: 8.02 (AA' of
AA'BB', J ˆ 8.0, 2 arom. H); 7.48 ± 7.32 (m, 4 arom. H); 7.28± 7.22 ( m, 1 arom. H); 7.02 (d-like, 2 arom. H).
13C-NMR: 147.8( s, 1 arom. C); 140.1 (s, NCSe); 139.3, 138.6 (2s, 2 arom. C); 131.0 (s, CN2); 129.4, 129.05,
.
‡
128.98, 125.7, 121.0 (5d, 9 arom. C). EI-MS: 320 (0.5, M ), 239 (2), 216 (20), 215 (10), 214 (82), 77 (100). Anal.
calc. for C14H9ClN2Se (319.65): C 52.58, H 2.82, Cl 11.11, N 8.76; found: C 52.51, H 2.79, Cl 11.15, N 8.77.
3. Preparation of Selenourea Derivatives 7: General Procedure. To a stirred soln. of 2 in acetone, 1 equiv. of
NH3, a primary or secondary amine was added at r.t. The soln. became orange immediately. After 5 ± 30 min, 2
was completely consumed (TLC), and the soln. was poured into H2O. In most of the cases, a yellow precipitate
was formed during stirring for 1 h. When an emulsion was formed, the mixture was stirred for another few hours,
9
)
The KSeCN used was prepared by dissolving powdered Se in a refluxing EtOH soln. of 1 equiv. of KCN.
After stirring for 5 h, no Se was left, the EtOH was evaporated, and KSeCN was dried at 1208 for 12 h.

Helvetica Chimica Acta ± Vol. 83 (2000)
1589
and a small amount of MgSO4 was added to accelerate the precipitation. The solid was filtered by suction and
air-dried; the products were pure enough for further reaction. For anal. purposes, an aliquot was recrystallized to
give yellow or yellowish crystals.
N2-[(Morpholin-4-yl)(selenocarbonyl)]-N1-phenylbenzimidamide (7a). From 10.2 mmol of 2a and mor-
pholine: 3.50 g (92%). M.p. 85 ± 868 (dec., AcOEt). IR: 3444w (br.), 3178m, 3114m, 3046m, 2958m, 2894m,
2864m, 1608s, 1588s, 1574s, 1532s, 1481s, 1434s, 1358m, 1325m, 1312s, 1277s, 1223s, 1176m, 1154w, 1120s, 1112s,
1083s, 1025m. 1H-NMR: 11.70 (s, NH); 7.60 ± 6.95 (m, 10 arom. H); 4.37, 4.14 (2t, J ˆ 4.9, 2 CH2O); 3.81, 3.72
(2t, J ˆ 4.9, 2 CH2N). 13C-NMR: 184.6, 159.1 (2s, CSe, CN2); 138.3, 135.0 (2s, 2 arom. C); 130.8, 129.1, 128.9,
‡
128.3, 125.1, 123.0 (6d, 10 arom. C); 66.7, 66.3 (2t, 2 CH2O); 50.9, 48.3 (2t, 2 CH2N). CI-MS: 374 (56, [M ‡ 1] ),
294 (100). Anal. calc. for C18H19N3OSe (372.33): C 58.06, H 5.11, N 11.29; found: C 58.81, H 5.17, N 11.20.
N1-Phenyl-N2-[(pyrrolidin-1-yl)(selenocarbonyl)]benzimidamide (7b). From 3.8mmol of 2a and pyrroli-
dine: 1.00 g (74%). M.p. 145.5 ± 146.58 (EtOH). IR: 3441w (br.), 3172m, 3109m, 3027m, 2962m, 2868m, 1616s,
1590s, 1576s, 1532s, 1490s, 1472s, 1439s, 1331s, 1282m, 1258m, 1223m, 1176m, 1110w, 1075m, 1027w, 1000w.
1H-NMR: 12.00 (s, NH); 7.55 ± 6.90 (m, 10 arom. H); 3.87, 3.80 (2t, J ˆ 6.5, 2 CH2N); 2.09 ± 1.94 (m, 2 CH2).
13C-NMR: 180.3, 158.4 (2s, CSe, CN2); 138.7, 135.3 (2s, 2 arom. C); 130.8, 129.4, 128.9, 128.2, 124.8, 123.0 (6d,
‡
10 arom. C); 53.5, 50.7 (2t, 2 CH2N); 25.6, 24.5 (2t, 2 CH2). CI-MS: 358(25, [ M ‡ 1] ), 278(100). Anal. calc. for
C18H19N3Se (356.33): C 60.67, H 5.34, N 11.80; found: C 60.55, H 5.51, N 11.75.
N1-Phenyl-N2-[(piperidin-1-yl)(selenocarbonyl)]benzimidamide (7c). From 3.0 mmol of 2a and piper-
idine: 0.89 g (80%). M.p. 143 ± 1448 (EtOH). IR: 3442w (br.), 3242m, 3183m, 3106m, 3040m, 2933m, 2858m,
1621s, 1590s, 1541s, 1493s, 1460s, 1439s, 1367m, 1346m, 1327m, 1308m, 1282s, 1262s, 1234s, 1192s, 1177m, 1131s,
1122m, 1077m, 1061m, 1025m, 1001m. 1H-NMR: 10.90 (s, NH); 7.53 ± 6.97 (m, 10 arom. H); 4.28(br. s, CH2N);
3.80 (t, J ˆ 6.5, CH2N); 2.09 ± 1.94 (m, 2 CH2). 13C-NMR: 183.4, 157.0 (2s, CSe, CN2); 138.7, 135.0 (2s,
2 arom. C); 130.7, 129.1, 128.8, 128.2, 124.5, 122.5 (6d, 10 arom. C); 52.4, 49.0 (2t, 2 CH2N); 26.1, 25.7, 24.4 (3t,
‡
3 CH2). CI-MS: 372 (100, [M ‡ 1] ), 292 (67). Anal. calc. for C19H21N3Se (370.36): C 61.62, H 5.68, N 11.35;
found: C 61.59, H 5.79, N 11.31.
N2-[Amino(selenocarbonyl)]-N1-phenylbenzimidamide (7d). From 10.4 mmol of 2a and NH3: 2.06 g
(65%). M.p. 183 ± 1848 (dec.; acetone). IR: 3430w (br.), 3242s, 3188s, 3080s, 3040m, 1646s, 1599s, 1578m, 1522s,
1488s, 1446s, 1313m, 1286s, 1267s, 1221s, 1117s, 1075w, 1034m. 1H-NMR: 11.77, 8.45, 7.70 (3s, 3 NH); 7.50 ± 6.95
‡
(m, 8arom. H); 6.69 ( d-like, 2 arom. H). CI-MS: 304 (44, [M ‡ 1] ), 224 (45), 197 (100). Anal. calc. for
C14H13N3Se (302.24): C 55.63, H 4.30, N 13.91; found: C 55.46, H 4.36, N 13.98.
N1-{[(Methyl)(phenyl)amino](selenocarbonyl)}-N2-phenylbenzimidamide (7e). From 6.95 mmol of 2a and
N-methylaniline: 2.30 g (84%). M.p. 108 ± 1098 (dec.; EtOH). IR: 3420w (br.), 3248m, 3188m, 3114w, 3055m,
1619s, 1593s, 1574s, 1538s, 1491s, 1474m, 1440s, 1382s, 1331s, 1312s, 1297m, 1273m, 1208m, 1118m, 1085s, 1026w,
1001w. 1H-NMR: 12.40 (br. s, 0.25 H, NH); 10.80 (br. s, 0.75 H, NH); 7.57 ± 6.83 (m, 15 arom. H); 3.81 (s, 2.25 H,
MeN); 3.65 (s, 0.75 H, MeN). 13C-NMR: 187.3, 155.7 (2s, CSe, CN2); 145.9, 138.6, 134.2 (3s, 3 arom. C); 130.7,
‡
129.4, 129.1, 128.9, 127.9, 127.4, 125.7, 124.6, 122.4 (9d, 15 arom. C); 45.2 (q, MeN). CI-MS: 394 (84, [M ‡ 1] ),
315 (49), 273 (45), 108(100). Anal. calc. for C 21H19N3Se (392.36): C 64.29, H 4.85, N 10.71; found: C 64.12,
H 4.77, N 10.69.
4-Methyl-N2-[(morpholin-4-yl)(selenocarbonyl)]-N1-phenylbenzimidamide (7f). From 19.7 mmol of 2b
and morpholine: 6.47 g (85%). M.p. 178 ± 1798 (dec.; acetone). IR: 3442w (br.), 3214m, 3180m, 3112m, 3075m,
2980m, 2952m, 2917m, 2852m, 1606s, 1587s, 1527s, 1494s, 1478s, 1429s, 1358m, 1312s, 1277s, 1255m, 1223s, 1208s,
1182m, 1120s, 1080s, 1028m, 1016m. 1H-NMR: 11.50 (s, NH); 7.38, 7.12 (AA'BB', J ˆ 8.2, 4 arom. H); 7.22 (t-like,
2 arom. H); 7.08( t-like, 1 arom. H); 7.04 (d-like, 2 arom. H); 4.34, 4.10 (2t, J ˆ 4.9, 2 CH2O); 3.78, 3.70 (2t, J ˆ
4.9, 2 CH2N); 2.34 (s, Me). 13C-NMR: 184.6, 158.7 (2s, CSe, CN2); 141.4, 138.4, 132.0 (3s, 3 arom. C); 129.1,
129.0, 128.9, 124.9, 122.8 (5d, 9 arom. C); 66.7, 66.3 (2t, 2 CH2O); 51.0, 48.2 (2t, 2 CH2N); 21.4 (q, Me). CI-MS:
‡
388 (100, [M ‡ 1] ), 308(90). Anal. calc. for C 19H21N3OSe (386.36): C 59.07, H 5.44, N 10.88; found: C 58.83,
H 5.58, N 10.75.
Suitable crystals for the X-ray crystal-structure determination were grown from acetone.
N2-[Amino(selenocarbonyl)]-4-methyl-N1-phenylbenzimidamide (7g). From 10.8mmol of 2b and NH3:
2.05 g (60%). M.p. 1708 (dec., acetone). IR: 3430w (sh.), 3235s, 3064m, 1638s, 1597s, 1511s, 1484s, 1447m,
1283m, 1257s, 1224m, 1184s, 1112s, 1071w, 1026m. 1H-NMR: 11.80, 8.51, 7.85 (3s, 3 NH); 7.17 ± 7.07
(m, 6 arom. H); 6.97 (t-like, 1 arom. H); 6.67 (d-like, 2 arom. H); 2.31 (s, Me). 13C-NMR: 180.5, 155.3 (2s,
CSe, CN2); 146.3, 141.1, 128.4 (3s, 3 arom. C); 129.4, 128.7, 128.0, 123.9, 121.9 (5d, 9 arom. C); 21.3 (q, Me). CI-
‡
MS: 318(40, [ M ‡ 1] ), 236 (100), 211 (74). Anal. calc. for C15H15N3Se (316.27): C 56.96, H 4.75, N 13.29;
found: C 56.67, H 4.77, N 13.08.

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N2-[(Benzylamino)(selenocarbonyl)]-4-methyl-N1-phenylbenzimidamide (7h). From 7.3 mmol of 2b and
PhCH2NH2: 2.84 g (95%). M.p. 153 ± 1548 (acetone). IR: 3422w (br.), 3175m, 3134m, 3057m, 3021m, 2946m,
2913m, 1638s, 1597m, 1558s, 1526s, 1485s, 1452m, 1372w, 1341m, 1294m, 1273s, 1200m, 1174s, 1112w, 1084w,
1072w, 1026w. 1H-NMR: 13.00, 8.50 (2s, 2 NH); 7.43 ± 7.23 (m, 5 arom. H); 7.12 ± 7.04 (m, 6 arom. H); 6.93 (t-
like, 1 arom. H); 6.61 (d-like, 2 arom. H); 5.00 (d-like, PhCH2); 2.28( s, Me). 13C-NMR: 180.2, 155.9 (2s, CSe,
CN2); 146.1, 141.0, 136.3 (3s, 4 arom. C); 129.4, 128.70, 128.68, 128.0, 127.7, 127.6, 123.9, 122.2 (8d, 14 arom. C);
‡
52.7 (t, CH2N); 21.3 (q, Me). CI-MS: 408(100, [ M ‡ 1] ), 326 (69), 236 (28), 211 (50). Anal. calc. for
C22H21N3Se (406.39): C 65.02, H 5.17, N 10.34; found: C 64.91, H 5.24, N 10.34.
N1-{[(Methyl)(phenyl)amino](selenocarbonyl)}-N2-phenylbenzimidamide (7i). From 3.75 mmol of 2b and
N-methylaniline: 1.22 g (85%). M.p. 117.5 ± 118.58 (AcOEt). IR: 3417w (br.), 3238m, 3187m, 3120w, 3046m,
1621s, 1591s, 1534s, 1494s, 1440s, 1385s, 1327s, 1312s, 1271s, 1204m, 1184m, 1114m, 1085s, 1071s, 1028m.
1H-NMR: 12.40 (br. s, 0.25 H, NH); 10.90 (br. s, 0.75 H, NH); 7.46 ± 6.85 (m, 14 arom. H); 3.84 (s, 2.25 H,
MeN); 3.69 (s, 0.75 H, MeN); 2.37 (s, 0.75 H, Me); 2.26 (s, 2.25 H, Me). 13C-NMR (major isomer)10): 187.1, 155.9
(2s, CSe, CN2); 146.0, 141.2, 138.8, 131.3 (4s, 4 arom. C); 129.5, 129.0, 128.8, 128.6, 127.4, 127.3, 125.8, 124.4, 122.3
‡
(9d, 14 arom. C); 45.2 (q, MeN); 21.3 (q, Me). CI-MS: 408(17, [ M ‡ 1] ), 328(51), 108(100). Anal. calc. for
C22H21N3Se (406.39): C 65.02, H 5.17, N 10.34; found: C 64.88, H 5.12, N 10.39.
4-Chloro-N2-[(morpholin-4-yl)(selenocarbonyl)]-N1-phenylbenzimidamide (7j). From 15.3 mmol of 2c
and morpholine: 5.12 g (82%). M.p. 208 ± 2098 (dec.; acetone). IR: 3450w (br.), 3176m, 3112m, 3046m, 2954m,
2864m, 1610s, 1583s, 1531s, 1496s, 1432s, 1398m, 1374m, 1310m, 1291m, 1278s, 1253m, 1224s, 1208m, 1176m,
1
1119m, 1089s, 1076s, 1029m, 1010m. H-NMR: 12.00 (s, NH); 7.41 (AA' of AA'BB', J ˆ 8.5, 2 arom. H); 7.30 ±
7.18( m, 4 arom. H); 7.10 (t-like, 1 arom. H); 6.97 (d-like, 2 arom. H); 4.36, 4.12 (2t, J ˆ 4.8, 2 CH2O); 3.81, 3.72
(2t, J ˆ 4.9, 2 CH2N). 13C-NMR: 184.4, 158.3 (2s, CSe, CN2); 138.0, 137.0, 133.5 (3s, 3 arom. C); 130.6, 129.1,
.
‡
128.6, 125.4, 123.2 (5d, 9 arom. C); 66.7, 66.3 (2t, 2 CH2O); 50.9, 48.4 (2t, 2 CH2N). EI-MS: 407 (11, M ), 326
(8), 241 (20), 214 (34), 86 (40), 77 (100). Anal. calc. for C18H18ClN3OSe (406.77): C 53.14, H 4.43, Cl 8.73,
N 10.33; found: C 52.96, H 4.52, Cl 9.03, N 10.24.
4-Chloro-N2-[(dibutylamino)(selenocarbonyl)]-N1-phenylbenzimidamide (7k). From 10.1 mmol of 2c and
Bu2NH: 4.40 g (97%). M.p. 116.7 ± 117.58 (Et2O). IR: 3464w (sh.), 3238m, 3184m, 3120m, 3054m, 2955s, 2930m,
2870m, 1621s, 1586s, 1566m, 1540s, 1493s, 1441s, 1418s, 1398m, 1370m, 1352m, 1318s, 1262s, 1226m, 1208m,
1
1199m, 1178m, 1138m, 1097s, 1075m, 1014m. H-NMR: 11.40 (s, NH); 7.43, 7.26 (AA'BB', J ˆ 8.6, 4 arom. H);
7.19 (t-like, 2 arom. H); 7.05 (t-like, 1 arom. H); 6.90 (d-like, 2 arom. H); 3.97, 3.79 (2t, J ˆ 7.8, 2 CH2N); 1.8± 1.7,
1.7 ± 1.6 (2m, 2 CH2); 1.50 ± 1.25 (m, 2 CH2); 0.98, 0.93 (2t, J ˆ 7.3, 2 Me). 13C-NMR: 183.7, 155.9 (2s, CSe, CN2);
138.5, 136.7, 133.6 (3s, 3 arom. C); 130.6, 129.0, 128.4, 124.7, 122.8 (5d, 9 arom. C); 53.9, 51.0 (2t, 2 CH2N); 30.2,
‡
29.0, 20.3, 20.1 (4t, 4 CH2); 13.80, 13.77 (2q, 2 Me). CI-MS: 450 (53, [M ‡ 1] ), 370 (100). Anal. calc. for
C22H28ClN3Se (448.90): C 58.86, H 6.24, Cl 7.92, N 9.36; found: C 58.63, H 6.39, Cl 8.08, N 9.35.
N2-[Amino(selenocarbonyl)]-4-chloro-N1-phenylbenzimidamide (7l). From 2.8mmol of 2c and NH3:
0.70 g (75%). M.p. 1908 (dec.; acetone). IR: 3430w (sh.), 3237s (br.), 3066m, 1641s, 1599s, 1510s, 1482s, 1449m,
1400m, 1283s, 1259s, 1224s, 1178m, 1114s, 1092s, 1074m, 1027w, 1014m. 1H-NMR (major isomer)11): 9.85, 8.95,
8.82 (3s, 3 NH); 7.67 ± 7.55 (m, 5 arom. H); 7.38± 7.30 ( m, 2 arom. H); 7.16 ± 7.05 (m, 2 arom. H). 13C-NMR
(major isomer): 191.1, 150.5 (2s, CSe, CN2); 139.4, 135.2, 132.7 (3s, 3 arom. C); 130.2, 128.5, 128.2, 123.8, 120.7
‡
(5d, 9 arom. C). CI-MS: 338(31, [ M ‡ 1] ), 256 (100). Anal. calc. for C14H12ClN3Se (336.68): C 49.93, H 3.57,
Cl 10.55, N 12.48; found: C 49.96, H 3.58, Cl 10.68, N 12.48.
4-Chloro-N1-{[(methyl)(phenyl)amino](selenocarbonyl)}-N2-phenylbenzimidamide (7m). From 19.4 mmol
of 2c and N-methylaniline: 7.60 g (92%). M.p. 1608 (dec.; AcOEt). IR: 3428w (br.), 3235w, 3185m, 3112m,
3054m, 1621s, 1588s, 1567m, 1542s, 1494s, 1442s, 1391s, 1345s, 1275s, 1248m, 1210s, 1180m, 1092s, 1028w, 1014m.
1H-NMR: 12.70 (br. s, 0.2 H, NH); 11.10 (br. s, 0.8H, NH); 7.51 ± 6.81 ( m, 14 arom. H); 3.82 (s, 2.4 H, MeN);
3.65 (s, 0.6 H, MeN). 13C-NMR (major isomer)10): 187.1, 155.0 (2s, CSe, CN2); 146.0, 138.4, 136.9, 132.7 (4s,
4 arom. C); 130.9, 129.1, 129.0, 128.2, 127.4, 125.7, 124.8, 122.6 (8d, 14 arom. C); 45.1 (q, MeN). CI-MS: 428(100,
‡
[M ‡ 1] ), 348(53), 216 (26), 108(43). Anal. calc. for C 21H18ClN3Se (426.81): C 59.09, H 4.22, Cl 8.32, N 9.85;
found: C 58.86, H 4.45, Cl 8.47, N 9.79.
10
)
)
All signals are doubled; ratio ca. 3 :1.
11
There are signals of two isomers present. The second isomer shows signals for NH at 11.32, 10.78, and
9.97 ppm, and for arom. H at 7.25 (d-like, 2 H), 6.90 (t-like, 1 H), and 6.68( d-like, 2 H); ratio of the isomers
ca. 3 :1.

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4. Preparation of 1,3-Selenazoles 9: General Procedure A. To a stirred soln. of 7 in acetone, 1 equiv. of
bromide (BrCH2Z) was added at r.t. Within a few min, the iminium salt was precipitated. The mixture was
concentrated i.v., and the precipitate was filtered. The solid was suspended in acetone, and 1.1 ± 1.3 equiv. of
Et3N or NaH was added. After a few min, a clear soln. was formed, and then a solid precipitated. After stirring
for 10 ± 30 min, the mixture was poured into ice/H2O, and stirred for another 10 min to 1 h. The precipitate was
filtered by suction and air-dried. For anal. purposes, an aliquot was recrystallized to give white or yellowish
crystals.
General Procedure B. A soln. of isoselenocyanate 2 in acetone was treated subsequently with an amine
according to Sect. 3 and with BrCH2Z according to General Procedure A in Sect. 4.
[2-(Morpholin-4-yl)-4-phenyl-1,3-selenazol-5-yl](4-nitrophenyl)methanone (9a). From 2.8mmol of 7a and
4-nitrophenacyl bromide (ˆ2-bromo-1-(4-nitrophenyl)ethanone): 1.10 g (90%). M.p. 196.4 ± 197.48 (EtOH).
IR: 3063w, 2972w, 2950w, 2896w, 2858w, 1609s, 1592s, 1546s, 1518s, 1472s, 1441s, 1386w, 1370m, 1341s, 1286s,
1261s, 1225m, 1172w, 1157w, 1116s, 1066m, 1032m, 1012m. 1H-NMR: 7.85, 7.46 (AA'BB', J ˆ 8.9, 4 arom. H);
7.23 ± 7.18( m, 2 arom. H); 7.14 ± 7.07 (m, 1 arom. H); 7.04 ± 6.97 (m, 2 arom. H); 3.83 (t, J ˆ 4.9, 2 CH2O); 3.66
(t, J ˆ 4.9, 2 CH2N). 13C-NMR: 187.8 (s, CO); 174.4, 161.7, 128.0 (3s, C(2), C(4), C(5)); 148.5, 143.8, 135.2 (3s,
3 arom. C); 129.9, 129.6, 129.1, 127.6, 122.5 (5d, 9 arom. C); 66.0 (t, 2 CH2O); 49.4 (t, 2 CH2N). APCI-MS
‡
(MeOH/H2O/NH4OAc): 444 ([M ‡ 1] ). Anal. calc. for C20H17N3O4Se (442.34): C 54.30, H 3.85, N 9.50; found:
C 54.22, H 4.02, N 9.49.
[4-Phenyl-2-(pyrrolidin-1-yl)-1,3-selenazol-5-yl](4-nitrophenyl)methanone (9b). From 1.4 mmol of 7b and
4-nitrophenacyl bromide: 0.58g (97%). M.p. 219.1 ± 219.8 8 (acetone). IR: 3076w, 2981w, 2947w, 2887w, 2840w,
1607m, 1584s, 1557s, 1517s, 1503s, 1473s, 1442m, 1406w, 1343s, 1327s, 1312s, 1286s, 1267s, 1244m, 1178w, 1140w,
1101m, 1076w, 1026w, 1013w. 1H-NMR (235 K): 7.84, 7.39 (AA'BB', J ˆ 8.9, 4 arom. H); 7.17 (d-like, 2 arom. H);
7.07 (t-like, 1 arom. H); 6.98( t-like, 2 arom. H); 3.79, 3.38(2 t, J ˆ 6.4, 2 CH2N); 2.18, 2.10 (2 quint., J ˆ 6.6,
2 CH2). 13C-NMR (235 K): 187.7 (s, CO); 170.4, 163.0, 127.0 (3s, C(2), C(4), C(5)); 147.5, 144.0, 134.8(3 s,
3 arom. C); 129.7, 129.4, 129.0, 127.6, 122.4 (5d, 9 arom. C); 52.3, 49.4 (2t, 2 CH2N); 25.7, 25.4 (2t, 2 CH2). EI-
.
‡
MS: 427 (48, M ), 398(10), 304 (13), 181 (44), 179 (20), 177 (11), 176 (12), 150 (73), 129 (24), 120 (30), 104
(100). Anal. calc. for C20H17N3O3Se (426.34): C 56.34, H 3.99, N 9.86; found: C 56.22, H 4.01, N 9.80.
{2-[(Methyl)(phenyl)amino]-4-phenyl-1,3-selenazol-5-yl}(4-nitrophenyl)methanone (9c). From 2.8mmol
of 7e and 4-nitrophenacyl bromide: 1.23 g (95%). M.p. 178.7 ± 179.38 (EtOH). IR: 3057w, 2933w, 1608m, 1592s,
1510s (br.), 1472s, 1453s, 1403s, 1343s, 1335s, 1305s, 1289s, 1165m, 1127m, 1100m, 1012m. 1H-NMR: 7.84 (AA' of
AA'BB', J ˆ 8.9, 2 arom. H); 7.53 ± 7.37 (m, 7 arom. H); 7.29 ± 7.23 (m, 2 arom. H); 7.12 ± 7.07 (m, 1 arom. H);
7.05 ± 6.95 (m, 2 arom. H); 3.63 (s, MeN). 13C-NMR: 188.0 (s, CO); 174.5, 161.4, 127.56 (3s, C(2), C(4), C(5));
148.4, 146.4, 144.0, 135.4 (4s, 4 arom. C); 130.4, 130.0, 129.6, 129.0, 128.4, 127.64, 125.3, 122.5 (8d, 14 arom. C);
‡
40.3 (q, MeN). APCI-MS (MeOH/H2O/NH4OAc): 464 ([M ‡ 1] ). Anal. calc. for C23H17N3O3Se (462.37):
C 59.74, H 3.68, N 9.09; found: C 59.58, H 3.68, N 9.08.
Suitable crystals for the X-ray crystal-structure determination were grown from EtOH.
(4-Methoxyphenyl)[4-phenyl-2-(piperidin-1-yl)-1,3-selenazol-5-yl]methanone (9d). From 4.3 mmol of 7c
and 4-methoxyphenacyl bromide: 1.80 g (98%). M.p. 158 ± 1598 (acetone). IR: 3006w, 2966w, 2945m, 2859w,
2840w, 1605s, 1588s, 1572m, 1535s, 1506s, 1470s, 1444s, 1339s, 1305s, 1282s, 1249s, 1170m, 1131m, 1105m, 1072w,
1
1033m, 1024m, 1008m. H-NMR: 7.44, 6.54 (AA'BB', J ˆ 8.9, 4 arom. H); 7.33 (dd-like, 2 arom. H); 7.12 ± 7.01
(m, 3 arom. H); 3.69 (s, MeO); 3.57 (br. s, 2 CH2N); 1.68(br. s, 3 CH2). 13C-NMR: 188.9 (s, CO); 173.0, 161.9,
127.0 (3s, C(2), C(4), C(5)); 159.1, 136.1, 130.9 (3s, 3 arom. C); 131.3, 129.9, 128.1, 127.4, 112.7 (5d, 9 arom. C);
‡
55.2 (q, MeO); 50.5 (t, 2 CH2N); 25.2 (t, 2 CH2); 24.0 (t, CH2). CI-MS: 427 (100, [M ‡ 1] ), 236 (50). Anal. calc.
for C22H22N2O2Se (425.39): C 62.12, H 5.18, N 6.59; found: C 62.06, H 5.28, N 6.58.
Suitable crystals for the X-ray crystal-structure determination were grown from acetone.
Ethyl 2-(Morpholin-4-yl)-4-phenyl-1,3-selenazole-5-carboxylate (9e). From 12.5 mmol of 7a and ethyl 2-
bromoacetate: 4.00 g (88%). M.p. 97.7 ± 98.58 (hexane/Et2O). IR: 3068w, 3025w, 2982m, 2905m, 2861m, 1667s,
1530s, 1483s, 1448m, 1392m, 1366s, 1309s, 1298s, 1256s, 1231s, 1192w, 1137m, 1111s, 1067s, 1031m, 1021m.
1H-NMR: 7.70 ± 7.64 (m, 2 arom. H); 7.38± 7.34 ( m, 3 arom. H); 4.16 (q, J ˆ 7.1, MeCH2O); 3.79 (t, J ˆ 4.9,
2 CH2O); 3.55 (t, J ˆ 4.9, 2 CH2N); 1.20 (t, J ˆ 7.1, Me ) . 13C-NMR: 163.3 (s, CO); 173.2, 160.7, 115.0 (3s, C(2),
C(4), C(5)); 135.6 (s, 1 arom. C); 129.8, 128.8, 127.5 (3d, 5 arom. C); 66.1 (t, 2 CH2O); 60.7 (t, MeCH2O); 49.3
‡
(t, 2 CH2N); 14.2 (q, Me). CI-MS: 367 ([M ‡ 1] ). Anal. calc. for C16H18N2O3Se (365.29): C 52.60, H 4.93,
N 7.67; found: C 52.56, H 5.06, N 7.68.
Ethyl 4-Phenyl-2-(pyrrolidin-4-yl)-4-phenyl-1,3-selenazole-5-carboxylate (9f). From 1.4 mmol of 7b and
ethyl 2-bromoacetate: 0.40 g (80%). M.p. 111.5 ± 112.58 (Et2O). IR: 3047w, 2970m, 2951m, 2900w, 2871m,
2852m, 1657s, 1600w, 1552s, 1515s, 1480s, 1447m, 1391w, 1366m, 1340m, 1319s, 1305s, 1282s, 1264s, 1242s, 1185m,

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Helvetica Chimica Acta ± Vol. 83 (2000)
1171m, 1126m, 1066s, 1026m. 1H-NMR: 7.70 ± 7.65 (m, 2 arom. H); 7.38± 7.34 ( m, 3 arom. H); 4.14 (q, J ˆ 7.1,
CH2O); 3.48(br. s, 2 CH2N); 2.10 ± 2.00 (m, 2 CH2); 1.19 (t, J ˆ 7.1, Me ) . 13C-NMR: 163.4 (s, CO); 169.1, 161.4,
113.5 (3s, C(2), C(4), C(5)); 136.0 (s, 1 arom. C); 129.7, 128.5, 127.4 (3d, 5 arom. C); 60.3 (t, CH2O); 50.4
‡
(t, 2 CH2N); 25.5 (t, 2 CH2); 14.2 (q, Me). ESI-MS (MeOH): 351 ([M ‡ 1] ). Anal. calc. for C16H18N2O2Se
(349.29): C 55.01, H 5.16, N 8.02; found: C 54.98, H 5.29, N 8.01.
Ethyl 2-[(Methyl)(phenyl)amino]-4-phenyl-1,3-selenazole-5-carboxylate (9g). From 5.85 mmol of 7e and
ethyl 2-bromoacetate: 1.78 g (79%). M.p. 87.5 ± 88.58 (hexane). IR: 3058w, 2981w, 2938w, 2898w, 1703s, 1597w,
1586w, 1514s (br.), 1496s, 1479s, 1451m, 1406s, 1360w, 1337s, 1335s, 1278s, 1232s, 1180m, 1157w, 1122s, 1054s,
1028m, 1020m. 1H-NMR: 7.76 ± 7.71 (m, 2 arom. H); 7.50 ± 7.33 (m, 8arom. H); 4.10 ( q, J ˆ 7.1, CH2O); 3.57
(s, MeN); 1.16 (t, J ˆ 7.1, Me ) . 13C-NMR: 163.3 (s, CO); 172.8, 160.5, 114.3 (3s, C(2), C(4), C(5)); 146.7, 135.7
(2s, 2 arom. C); 130.2, 129.7, 128.6, 127.8, 127.4, 125.4 (6d, 10 arom. C); 60.4 (t, CH2O); 40.0 (q, MeN); 14.4
‡
(q, Me). CI-MS: 387 (100, [M ‡ 1] ), 349 (10). Anal. calc. for C19H18N2O2Se (385.33): C 59.22, H 4.68, N 7.27;
found: C 59.25, H 4.76, N 7.33.
2-[(Methyl)(phenyl)amino]-4-phenyl-1,3-selenazole-5-carbonitrile (9h). From 2.75 mmol of 7e and 2-
bromoacetonitrile: 0.79 g (85%). M.p. 108 ± 1098. IR: 3055w, 2931w, 2895w, 2190m, 1586w, 1515s (br.), 1496m,
1478s, 1455m, 1440m, 1406s, 1349s, 1327m, 1292m, 1280m, 1266m, 1179w, 1162w, 1154w, 1126w, 1081w, 1028w,
1019w, 1000w. 1H-NMR: 8.12 ± 8.07 (m, 2 arom. H); 7.53 ± 7.38( m, 8arom. H); 3.62 ( s, MeN). 13C-NMR: 173.2,
162.8(2 s, C(2), C(4)); 146.2, 133.7 (2s, 2 arom. C); 130.5, 129.6, 128.5, 128.2, 125.3 (5d, 10 arom. C); 116.7
‡
(s, CꢀN); 88.4 (s, C(5)); 40.6 (q, MeN). CI-MS: 340 ([M ‡ 1] ). Anal. calc. for C17H13N3Se (338.27): C 60.36,
H 3.85, N 12.43; found: C 60.45, H 3.80, N 12.34.
[4-(4-Methylphenyl)-2-(morpholin-4-yl)-1,3-selenazol-5-yl]phenylmethanone (9i). From 2.5 mmol of 7f
and phenacyl bromide: 1.02 g (96%). M.p. 174.5 ± 175.08 (EtOH). IR: 3022w, 2968m, 2948w, 2861m, 1605s,
1574m, 1541s, 1476s, 1446s, 1428m, 1406w, 1375w, 1321s, 1302s, 1283s, 1260s, 1227s, 1172w, 1180m, 1156w, 1115s,
1
1100m, 1068m, 1029m. H-NMR: 7.42 (AA' of AA'BB', J ˆ 8.4, 2 arom. H); 7.22 ± 7.16 (m, 3 arom. H); 7.05 (t-
like, 2 arom. H); 6.82 (d-like, 2 arom. H); 3.81 (t, J ˆ 4.9, 2 CH2O); 3.61 (t, J ˆ 4.9, 2 CH2N); 2.18( s, Me).
13C-NMR: 190.2 (s, CO); 173.6, 159.9, 127.8(3 s, C(2), C(4), C(5)); 138.4, 138.2, 132.8 (3s, 3 arom. C); 130.8,
.
‡
129.9, 129.1, 128.1, 127.4 (5d, 9 arom. C); 66.0 (t, 2 CH2O); 49.2 (t, 2 CH2N); 21.1 (q, Me). EI-MS: 412 (17, M ),
114 (25), 105 (75), 77 (100). Anal. calc. for C21H20N2O2Se (411.37): C 61.31, H 4.87, N 6.81; found: C 61.21,
H 4.75, N 6.79.
[4-(4-Methylphenyl)-2-(morpholin-4-yl)-1,3-selenazol-5-yl](4-nitrophenyl)methanone (9j). From 2.4 mmol
of 7f and 4-nitrophenacyl bromide: 1.03 g (95%). M.p. 194 ± 194.58 (EtOH). IR: 3080w, 2966w, 2916w, 2858m,
1608s, 1590s, 1514s, 1473s, 1446s, 1435s, 1406w, 1331s, 1308s, 1291s, 1263s, 1230s, 1184w, 1148w, 1119s, 1100m,
1071w, 1036m, 1022m. 1H-NMR: 7.86, 7.46 (AA'BB', J ˆ 8.8, 4 arom. H); 7.09, 6.81 (AA'BB', J ˆ 8.0, 4 arom. H);
3.83 (t, J ˆ 4.9, 2 CH2O); 3.66 (t, J ˆ 4.9, 2 CH2N); 2.17 (s, Me). 13C-NMR: 187.8 (s, CO); 174.2, 162.0, 127.8(3 s,
C(2), C(4), C(5)); 148.3, 143.9, 139.5, 132.4 (4s, 4 arom. C); 129.9, 129.6, 128.3, 122.5 (4d, 8arom. C); 66.0
‡
(t, 2 CH2O); 49.4 (t, 2 CH2N); 21.0 (q, Me). CI-MS: 458(74, [ M ‡ 1] ), 428(100). Anal. calc. for C 21H19N3O4Se
(456.34): C 55.26, H 4.17, N 9.21; found: C 55.08, H 4.22, N 9.13.
4-(4-Methylphenyl)-2-(morpholin-4-yl)-1,3-selenazole-5-carboxamide (9k). From 2.8mmol of 7f and 2-
bromoacetamide: 0.80 g (81%). M.p. 230.5 ± 231.58 (acetone). IR: 3436s, 3296m, 3158s, 2957m, 2914m, 2849m,
1639s, 1580s, 1531s, 1493s, 1447m, 1433m, 1398s, 1318s, 1268s, 1231s, 1182m, 1137m, 1118s, 1070w, 1031m.
1H-NMR: 7.45, 7.25 (AA'BB', J ˆ 8.0, 4 arom. H); 5.60 (s, 2 H); 3.78( t, J ˆ 4.9, 2 CH2O); 3.52 (t, J ˆ 4.9,
2 CH2N); 2.39 (s, Me). 13C-NMR: 172.9, 165.1, 123.1 (3s, C(2), C(4), C(5)); 154.8( s, CO); 139.4, 132.3 (2s,
2 arom. C); 129.7, 128.9 (2d, 4 arom. C); 66.0 (t, 2 CH2O); 49.0 (t, 2 CH2N); 21.3 (q, Me). CI-MS: 352 ([M ‡
‡
1] ). Anal. calc. for C15H17N3O2Se (350.28): C 51.43, H 4.86, N 12.00; found: C 51.45, H 4.92, N 12.09.
Ethyl 4-(4-Methylphenyl)-2-(morpholin-4-yl)-1,3-selenazole-5-carboxylate (9l). From 5.0 mmol of 7f and
ethyl 2-bromoacetate: 1.60 g (85%). M.p. 130 ± 130.68 (acetone). IR: 2980m, 2905m, 2863m, 1700m, 1666s,
1612w, 1530s, 1489s, 1448m, 1393m, 1366s, 1318s, 1307s, 1288s, 1257s, 1232s, 1212m, 1192m, 1137m, 1113s, 1068s,
1
1022m. H-NMR: 7.59, 7.17 (AA'BB', J ˆ 8.1, 4 arom. H); 4.16 (q, J ˆ 7.1, MeCH2O); 3.77 (t, J ˆ 4.9, 2 CH2O);
3.65 (t, J ˆ 4.9, 2 CH2N); 2.36 (s, Me); 1.22 (t, J ˆ 7.1, Me ) . 13C-NMR: 163.2 (s, CO); 173.0, 160.8, 114.3 (3s, C(2),
C(4), C(5)); 138.6, 132.6 (2s, 2 arom. C); 129.6, 128.1 (2d, 4 arom. C); 66.0 (t, 2 CH2O); 60.5 (t, MeCH2O); 49.1
‡
(t, 2 CH2N); 21.3 (q, Me); 14.2 (q, Me). CI-MS: 381 (100, [M ‡ 1] ), 211 (23), 191 (11). Anal. calc. for
C17H20N2O3Se (379.32): C 53.83, H 5.28, N 7.39; found: C 53.73, H 5.18, N 7.40.
4-(4-Methylphenyl)-2-[(methyl)(phenyl)amino]-1,3-selenazole-5-carbonitrile (9m). From 2.15 mmol of 7i
and 2-bromoacetonitrile: 0.68g (90%). M.p. 149.5 ± 150 8. IR: 3050w, 2939w, 2194s, 1586w, 1510s (br.), 1494s,
1456s, 1403s, 1349s, 1328m, 1302m, 1276m, 1264m, 1184m, 1116m, 1082m, 1035w, 1018w. 1H-NMR: 8.00, 7.25
(AA'BB', J ˆ 8.2, 4 arom. H); 7.50 (t-like, 2 arom. H); 7.43 ± 7.36 (m, 3 arom. H); 3.62 (s, MeN); 3.29 (s, Me).

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13C-NMR: 173.2, 162.9 (2s, C(2), C(4)); 146.2, 139.8, 131.1 (3s, 3 arom. C); 130.5, 129.2, 128.5, 128.1, 125.3 (5d,
‡
10 arom. C); 116.9 (s, CꢀN); 87.7 (s, C(5)); 40.5 (q, MeN); 21.1 (q, Me). CI-MS: 354 ([M ‡ 1] ). Anal. calc. for
C18H15N3Se (352.30): C 61.36, H 4.26, N 11.93; found: C 61.44, H 4.40, N 11.81.
4-{4-(4-Methylphenyl)-2-[(methyl)(phenyl)amino]-1,3-selenazol-5-yl}benzonitrile (9n). From 3.7 mmol of
7i and 4-(bromomethyl)benzonitrile: 1.35 g (86%). M.p. 219.2 ± 220.58. IR: 3027w, 2939w, 2224m, 1598m, 1584w,
1522s, 1504s, 1454m, 1403s, 1320m, 1299m, 1262m, 1180w, 1127m, 1103m, 1019w. 1H-NMR: 7.50 ± 7.30
(m, 9 arom. H); 7.21 (t-like, 2 arom. H); 7.09 (d-like, 2 arom. H); 3.59 (s, MeN); 2.34 (s, Me). 13C-NMR: 170.0,
149.6 (2s, C(2), C(4)); 147.2, 140.4, 137.8, 132.8 (4s, 4 arom. C); 132.0, 130.0, 129.6, 129.2, 129.0, 127.3, 125.2 (7d,
13 arom. C); 123.2, 109.3 (2s, C(5), 1 arom. C); 118.9 (s, CꢀN); 39.9 (q, MeN); 21.2 (q, Me). CI-MS: 430 (100,
‡
[M ‡ 1] ), 349 (59). Anal. calc. for C24H19N3Se (428.40): C 67.29, H 4.44, N 9.81; found: C 67.08, H 4.50, N 9.72.
[4-(4-Chlorophenyl)-2-(morpholin-4-yl)-1,3-selenazol-5-yl](4-nitrophenyl)methanone
(9o).
From
2.4 mmol of 7j and 4-nitrophenacyl bromide: 1.10 g (95%). M.p. 234.5 ± 2358 (acetone). IR: 3081w, 2965w,
2919w, 2857w, 1608m, 1588s, 1514s, 1470s, 1446s, 1434s, 1400m, 1349s, 1330s, 1300s, 1289s, 1272s, 1262s, 1232s,
1177w, 1149w, 1119s, 1100m, 1084m, 1038w, 1016m. 1H-NMR: 7.94, 7.51 (AA'BB', J ˆ 8.5, 4 arom. H); 7.19, 7.02
(AA'BB', J ˆ 8.3, 4 arom. H); 3.84 (t, J ˆ 4.7, 2 CH2O); 3.65 (t, J ˆ 4.7, 2 CH2N). 13C-NMR: 187.5 (s, CO); 174.3,
160.0, 127.84 (3s, C(2), C(4), C(5)); 148.6, 143.7, 135.4, 133.6 (4s, 4 arom. C); 131.1, 129.7, 127.85, 122.7 (4d,
‡
8arom. C); 66.0 ( t, 2 CH2O); 49.4 (t, 2 CH2N). CI-MS: 478(100, [ M ‡ 1] ), 448(66). Anal. calc. for
C20H16ClN3O4Se (476.78): C 50.37, H 3.36, Cl 7.45, N 8.81; found: C 50.30, H 3.47, Cl 7.61, N 8.79.
[4-(4-Chlorophenyl)-2-(dibutylamino)-1,3-selenazol-5-yl](4-nitrophenyl)methanone (9p). From 1.7 mmol
of 7k and 4-nitrophenacyl bromide: 0.82 g (92%). M.p. 131.5 ± 1328 (Et2O). IR: 3053w, 2956m, 2930m, 2862m,
1598w, 1584s, 1539s, 1504s, 1465s, 1402m, 1329s, 1290s, 1240m, 1178w, 1155w, 1101m, 1014m. 1H-NMR: 7.93, 7.50
(AA'BB', J ˆ 8.9, 4 arom. H); 7.18, 7.00 (AA'BB', J ˆ 8.6, 4 arom. H); 3.51 (br. s, 2 CH2N); 1.72 (quint., J ˆ 7.5,
4 H); 1.27 (sext., J ˆ 7.4, 4 H); 0.98( t, J ˆ 7.3, 2 Me). 13C-NMR: 187.1 (s, CO); 173.3, 169.7, 126.5 (3s, C(2), C(4),
C(5)); 148.4, 144.3, 135.1, 134.0 (4s, 4 arom. C); 131.2, 129.6, 127.7, 122.7 (4d, 8arom. C); 55 ± 50 (very br.,
‡
2 CH2N); 29.2, 20.0 (2t, 4 CH2); 13.7 (q, 2 Me). CI-MS: 420 (100, [M ‡ 1] ), 490 (20). Anal. calc. for
C24H26ClN3O3Se (518.90): C 55.54, H 5.01, Cl 6.85, N 8.10; found: C 55.68, H 5.21, Cl 6.92, N 8.01.
{4-(4-Chlorophenyl)-2-[(methyl)(phenyl)amino]-1,3-selenazol-5-yl}(4-nitrophenyl)methanone (9q). From
2.3 mmol of 7m and 4-nitrophenacyl bromide: 1.15 g (99%). M.p. 193 ± 1948 (acetone). IR: 3065w, 2939w,
2855w, 1613s, 1593s, 1570m, 1522s, 1467s, 1400s, 1322s (br.), 1301s (br.), 1161m, 1102m, 1084m, 1015m.
1H-NMR: 7.93 (AA' of AA'BB', J ˆ 8.8, 2 arom. H); 7.54 ± 7.38 (m, 7 arom. H); 7.25, 7.04 (AA'BB', J ˆ 8.5,
4 arom. H); 3.63 (s, MeN). 13C-NMR: 187.8 (s, CO); 174.7, 156.7, 127.4 (3s, C(2), C(4), C(5)); 148.8, 146.3, 144.1,
135.3, 134.0 (5s, 5 arom. C); 131.3, 130.6, 129.8, 128.6, 128.0, 125.4, 122.9 (7d, 13 arom. C); 40.4 (q, MeN). EI-
.
‡
MS: 497 (30, M ), 375 (5), 215 (26), 180 (14), 150 (74), 132 (12), 123 (12), 120 (31), 106 (97), 105 (21), 104
(100), 92 (57), 91 (67). Anal. calc. for C23H16ClN3O3Se (496.81): C 55.59, H 3.22, Cl 7.15, N 8.46; found: C 55.42,
H 3.23, Cl 7.39, N 8.62.
Ethyl 4-(4-Chlorophenyl)-2-(dibutylamino)-1,3-selenazole-5-carboxylate (9r). From 6.25 mmol of 7k and
ethyl 2-bromoacetate: 2.60 g (94%). Yellowish oil. IR (film): 2957s, 2931m, 2871m, 1699s, 1670m, 1595w, 1534s,
1478s, 1399m, 1362m, 1326s, 1294s, 1271s, 1233s, 1187m, 1123s, 1090s, 1056s, 1015m. 1H-NMR: 7.67, 7.33
(AA'BB', J ˆ 8.6, 4 arom. H); 4.16 (q, J ˆ 7.1, CH2O); 3.44 (br. t, 2 CH2N); 1.67 (quint., J ˆ 7.5, 4 H); 1.37
(sext., J ˆ 7.4, 4 H); 1.23 (t, J ˆ 7.1, Me); 0.96 (t, J ˆ 7.3, 2 Me). 13C-NMR: 171.8( s, CO); 163.3, 159.6, 112.8(3 s,
C(2), C(4), C(5)); 134.4, 134.1 (2s, 2 arom. C); 131.3, 127.4 (2d, 4 arom. C); 60.5 (t, CH2O); 52.3 (very br.,
‡
2 CH2N); 29.2, 20.0 (2t, 4 CH2); 14.2 (q, Me); 13.7 (q, 2 Me). CI-MS: 443 ([M ‡ 1] ). Anal. calc. for
C20H27ClN2O2Se (441.86): C 54.36, H 6.12, Cl 8.04, N 6.34; found: C 54.49, H 6.23, Cl 8.09, N 6.48.
Ethyl 4-(4-Chlorophenyl)-2-[(methyl)(phenyl)amino]-1,3-selenazole-5-carboxylate (9s). From 4.6 mmol of
7m and ethyl 2-bromoacetate: 1.65 g (85%). M.p. 140.7 ± 141.28 (Et2O). IR: 2974w, 2932w, 1701s, 1596w, 1584w,
1570w, 1509s, 1493s, 1477s, 1451m, 1400s, 1364m, 1340s, 1304m, 1290m, 1259s, 1241s, 1171m, 1156w, 1133s,
1097m, 1087m, 1058s, 1014m. 1H-NMR: 7.71 (AA' of AA'BB', J ˆ 8.4, 2 arom. H); 7.51 ± 7.33 (m, 7 arom. H);
4.12 (q, J ˆ 7.1, CH2O); 3.56 (s, MeN); 1.18( t, J ˆ 7.1, Me ) . 13C-NMR: 172.9 (s, CO); 163.2, 159.1, 114.5 (3s,
C(2), C(4), C(5)); 146.3, 134.5, 134.1 (3s, 3 arom. C); 131.2, 130.3, 127.9, 127.6, 125.4 (5d, 9 arom. C); 60.6
.
‡
(t, CH2O); 40.0 (q, MeN); 14.1 (q, Me). EI-MS: 420 (24, M ), 348(9), 215 (22), 180 (14), 136 (21), 123 (15),
107 (13), 106 (100), 105 (13), 91 (50). Anal. calc. for C19H17ClN2O2Se (419.77): C 54.35, H 4.05, Cl 8.46, N 6.67;
found: C 54.34, H 4.21, Cl 8.63, N 6.74.
Ethyl 4-(4-Chlorophenyl)-2-(morpholin-4-yl)-1,3-selenazole-5-carboxylate (9t). From 4.3 mmol of 7j and
ethyl 2-bromoacetate: 1.66 g (96%). M.p. 145.5 ± 1468 (Et2O). IR: 2988m, 2905m, 2864m, 1700m, 1666s, 1598w,
1572w, 1527s, 1480s, 1447m, 1393m, 1366s, 1314s, 1301s, 1288s, 1272s, 1256s, 1232s, 1192w, 1137m, 1110s, 1094s,
1
1067s, 1034m, 1020m. H-NMR: 7.64, 7.34 (AA'BB', J ˆ 8.7, 4 arom. H); 4.16 (q, J ˆ 7.1, MeCH2O); 3.80 (t, J ˆ

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Helvetica Chimica Acta ± Vol. 83 (2000)
4.9, 2 CH2O); 3.54 (t, J ˆ 4.9, 2 CH2N); 1.23 (t, J ˆ 7.1, Me ) . 13C-NMR: 163.1 (s, CO); 173.2, 159.2, 115.0 (3s,
C(2), C(4), C(5)); 134.6, 133.9 (2s, 2 arom. C); 131.2, 127.6 (2d, 4 arom. C); 66.0 (t, 2 CH2O); 60.7 (t, MeCH2O);
‡
49.1 (t, 2 CH2N); 14.1 (q, Me). CI-MS: 401 ([M ‡ 1] ). Anal. calc. for C16H17ClN2O3Se (399.74): C 48.06,
H 4.26, Cl 8.89, N 7.01; found: C 48.00, H 4.21, Cl 8.98, N 7.06.
4-(4-Chlorophenyl)-2-(morpholin-4-yl)-1,3-selenazole-5-carbonitrile (9u). From 2.4 mmol of 7j and 2-
bromoacetonitrile: 0.81 g (95%). M.p. 170 ± 1718 (acetone). IR: 2987w, 2958w, 2917w, 2876w, 2197s, 1596w,
1552s, 1511w, 1476m, 1461w, 1445m, 1400m, 1374w, 1342s, 1330m, 1318m, 1302m, 1272m, 1229m, 1172w, 1118s,
1100m, 1089m, 1069w, 1031m, 1016m. 1H-NMR: 8.00, 7.39 (AA'BB', J ˆ 8.8, 4 arom. H); 3.82 (t, J ˆ 4.9,
2 CH2O); 3.57 (t, J ˆ 4.9, 2 CH2N). 13C-NMR: 173.3, 161.5 (2s, C(2), C(4)); 135.7, 131.9 (2s, 2 arom. C); 129.5,
.
‡
128.7 (2d, 4 arom. C); 116.4 (s, CꢀN); 88.9 (s, C(5)); 65.9 (t, 2 CH2O); 49.6 (t, 2 CH2N). EI-MS: 353 (23, M ),
296 (17), 241 (23), 163 (33), 162 (19), 161 (100), 126 (20), 114 (13), 111 (10), 99 (13), 86 (11). Anal. calc. for
C14H12ClN3OSe (352.68): C 47.66, H 3.40, Cl 10.07, N 11.91; found: C 47.66, H 3.57, Cl 10.31, N 11.93.
5. Preparation of 1,3-Selenazoles 10: General Procedure. A soln. of 7d or 7l (R2 ˆ R3 ˆ H) and 1 equiv. of 4-
nitrophenacyl bromide in acetone was heated to reflux for 30 min. Then, the precipitated salt was filtered and
triturated in 5% aq. NaOH soln. for 1 h. The solid product was washed with H2O, filtered by suction, and air-
dried. For anal. purposes, an aliquot was recrystallized to give yellowish crystals.
N2-[4-(4-Nitrophenyl)-1,3-selenazol-2-yl]-N1-phenylbenzimidamide (10a). From 2.95 mmol of 7d and 4-
nitrophenacyl bromide: 1.30 g (98%). M.p. 218 ± 2198 (acetone). IR: 3367m, 3329m, 3102w, 3062w, 1638m,
1593s, 1570m, 1537s, 1516s, 1450m, 1407m, 1376m, 1336s, 1311s, 1277s, 1187m, 1108m, 1071w, 1046m, 1027w.
1H-NMR (223 K; major isomer)12): 10.20 (s, NH); 8.03, 7.63 (AA'BB', J ˆ 8.5, 4 arom. H); 7.88 (s, HÀC(5)); 7.19
(t-like, 2 arom. H); 7.08± 6.98 ( m, 2 arom. H); 6.94 ± 6.82 (m, 3 arom. H); 6.78( d-like, 2 arom. H). 13C-NMR
(223 K; major isomer): 162.4, 145.6 (2s, C(2), C(4)); 151.0 (s, CN2); 147.1, 146.3, 140.4, 130.1 (4s, 4 arom. C);
‡
129.9, 128.7, 128.1, 127.9, 126.1, 123.6, 123.1, 122.5 (8d, 14 arom. C); 117.3 (d, C(5)). CI-MS: 449 (100, [M ‡ 1] ),
418(30), 256 (21). Anal. calc. for C 22H16N4O2Se (447.36): C 59.06, H 3.58, N 12.53; found: C 58.91, H 3.63,
N 12.50.
4-Chloro-N2-[4-(4-nitrophenyl)-1,3-selenazol-2-yl]-N1-phenylbenzimidamide (10b). From 2.5 mmol of 7l
and 4-nitrophenacyl bromide: 1.05 g (87%). M.p. 223 ± 2248 (EtOH). IR: 3384m, 3063w, 1644s, 1594s, 1542s,
1507s, 1450m, 1408w, 1342s, 1310m, 1296m, 1274s, 1184w, 1101m, 1088m, 1044m, 1016m. 1H-NMR (major
isomer)13): 10.30 (s, NH); 8.15, 7.84 (AA'BB', J ˆ 8.8, 4 arom. H); 7.92 (s, HÀC(5)); 7.35 ± 6.90 (m, 7 arom. H);
6.75 (d-like, 2 arom. H). 13C-NMR (major isomer): 162.3, 146.4 (2s, C(2), C(4)); 150.6 (s, CN2); 148.5, 146.3,
140.4, 138.5, 130.6 (5s, 5 arom. C); 129.5, 128.8, 128.6, 126.4, 123.8, 123.5, 122.4 (7d, 13 arom. C); 117.3 (d, C(5)).
‡
CI-MS: 483 (100, [M ‡ 1] ), 453 (33), 370 (32), 231 (12). Anal. calc. for C22H15ClN4O2Se (481.80): C 54.83,
H 3.12, Cl 7.37, N 11.63; found: C 54.57, H 3.13, Cl 7.48, N 11.58.
6. Isolation of Intermediate Isoselenoureas 11: General Procedure (cf. Sect. 4). To a stirred soln. of 7 in
acetone, 1 equiv. of bromide (BrCH2Z) was added at r.t. After a few min, the mixture was concentrated i.v., and
the precipitate was filtered. The solid was suspended in acetone, and 1 equiv. of Et3N was added. After stirring
for 10 ± 30 min, the mixture was poured into ice/H2O and stirred for another 10 min to 1 h. The precipitate was
filtered by suction and air-dried. For anal. purposes, an aliquot was recrystallized to give white crystals.
Ethyl 2-{[((Morpholin-4-yl){[(phenyl)(phenylimino)methyl]imino})methyl]selanyl}acetate (11a). From
4.4 mmol of 7a and ethyl 2-bromoacetate: 1.90 g (94%). M.p. 63.5 ± 648 (Et2O). IR: 3061w, 2956m, 2842w,
1731s, 1606s, 1579s, 1482m, 1447m, 1425w, 1410w, 1392m, 1365m, 1309m, 1285m, 1263s, 1226m, 1218m, 1193w,
1167m, 1111s, 1057m, 1016s, 1001m. 1H-NMR: 8.00 ± 7.96 (m, 2 arom. H); 7.46 ± 7.37 (m, 3 arom. H); 7.30 ± 7.25
(m, 2 arom. H); 7.01 ± 6.96 (m, 3 arom. H); 4.01 (q, J ˆ 7.1, MeCH2O); 3.54 (t, J ˆ 4.6, 2 CH2O); 3.43 (t, J ˆ 4.5,
2 CH2N); 3.27 (s with satellite, J ˆ 6.2, CH2Se); 1.15 (t, J ˆ 7.1, Me ) . 13C-NMR: 169.4 (s, CO); 158.7, 150.0 (2s,
SeCN2, CN2); 148.9, 136.4 (2s, 2 arom. C); 130.4, 128.3, 128.1, 122.7, 122.1 (5d, 10 arom. C); 66.3 (t, 2 CH2O);
‡
61.5 (t, MeCH2O); 48.9 (t, 2 CH2N); 27.2 (t, CH2Se); 13.9 (q, Me). CI-MS: 460 (5, [M ‡ 1] ), 367 (73), 294 (49),
94 (100). Anal. calc. for C22H25N3O3Se (458.42): C 57.64, H 5.46, N 9.17; found: C 57.57, H 5.62, N 9.17.
N1-{[(Cyanomethyl)selanyl][(methyl)(phenyl)amino]methylidene}-N2-phenylbenzimidamide (11b). From
1.4 mmol of 7e and 2-bromoacetonitrile: 0.56 g (95%). M.p. 105.5 ± 1068 (Et2O). IR: 3059w, 2999w, 2932w,
2242m, 1618s, 1578s, 1560s, 1492s, 1480s, 1446m, 1414s, 1374m, 1347s, 1307m, 1272s, 1216m, 1185w, 1165m,
12
)
)
There are signals for two isomers present (ratio ca. 3 :1). The second isomer shows signals for NH at 12.70
and for the AA'BB' system at 8.33, 7.94 ppm (J ˆ 8.5).
13
There are signals for two isomers present (ratio ca. 3 :2). The second isomer shows signals for NH at 12.65,
for the AA'BB' system at 8.28, 7.95 (J ˆ 8.5), and for HÀC(5) at 8.06 ppm.

Helvetica Chimica Acta ± Vol. 83 (2000)
1595
1115m, 1068m, 1023m, 1008w. 1H-NMR: 8.21 ± 8.16 (m, 2 arom. H); 7.49 ± 7.45 (m, 3 arom. H); 7.39 (t-like,
2 arom. H); 7.28± 7.20 ( m, 3 arom. H); 7.12 (t-like, 1 arom. H); 7.05 (d-like, 2 arom. H); 6.58( dd, 2 arom. H);
3.35 (s with satellite, J ˆ 8.2, CH2Se); 3.13 (s, MeN). 13C-NMR: 157.2, 150.0 (2s, SeCN2, CN2); 148.8, 142.6, 136.3
(3s, 3 arom. C); 130.8, 129.4, 128.9, 128.7, 128.4, 128.2, 127.9, 122.8, 121.9 (9d, 15 arom. C); 117.4 (s, CꢀN); 41.3
‡
(q, MeN); 8.7 (t, CH2Se). CI-MS: 431 (<1, [M ‡ 1] ), 340 (100), 94 (67). Anal. calc. for C23H20N4Se (431.40):
C 64.04, H 4.64, N 12.99; found: C 63.92, H 4.74, N 12.98.
N1-{[(4-Cyanobenzyl)selanyl][(methyl)(phenyl)amino]methylidene}-4-methyl-N2-phenylbenzimidamide (11c).
From 6.8mmol of 7i and 4-(bromomethyl)benzonitrile: 3.25 g (92%). M.p. 124 ± 124.58 (Et2O). IR: 3059w,
3027w, 2925w, 2227m, 1621s, 1591s, 1574s, 1552s, 1507m, 1493m, 1446w, 1416m, 1342m, 1307w, 1269m, 1258m,
1
1214m, 1189w, 1174m, 1116m, 1068w, 1019w, 1001w. H-NMR: 7.91 (AA' of AA'BB', J ˆ 8.2, 2 arom. H); 7.42
(AA' of AA'BB', J ˆ 8.3, 2 arom. H); 7.33 (t-like, 2 arom. H); 7.24 ± 7.20 (m, 5 arom. H); 7.15 ± 7.03 (m, 5 ar-
om. H); 6.71 ± 6.65 (m, 2 arom. H); 3.48( s, CH2Se); 3.18( s, MeN); 2.43 (s, Me). 13C-NMR: 157.8, 150.3 (2s,
SeCN2, CN2); 144.0, 143.8, 140.8, 134.0, 110.5 (5s, 6 arom. C); 132.0, 129.7, 129.1, 128.8, 128.6, 128.1, 127.8, 127.7,
122.5, 122.2 (10d, 18arom. C); 118.6 ( s, CꢀN); 41.2 (q, MeN); 31.4 (t, CH2Se); 21.4 (q, Me). Anal. calc. for
C30H26N4Se (521.53): C 69.10, H 4.99, N 10.75; found: C 68.83, H 5.07, N 10.67.
N1-{[(4-Cyanobenzyl)selanyl](morpholin-4-yl)methylidene}-4-methyl-N2-phenylbenzimidamide (11d). From
2.5 mmol of 7f and 4-(bromomethyl)benzonitrile: 1.19 g (94%). M.p. 220 ± 2218 (acetone). IR: 3052w, 3025w,
2964w, 2921w, 2849w, 2224m, 1609s, 1595s, 1580s, 1507w, 1482m, 1461w, 1443w, 1424w, 1411w, 1394m, 1308w,
1292m, 1266m, 1225w, 1189w, 1199m, 1189m, 1169m, 1106m, 1068m, 1021m, 1014m, 1002m. 1H-NMR: 7.71 (AA'
of AA'BB', J ˆ 8.2, 2 arom. H); 7.40 (AA' of AA'BB', J ˆ 8.3, 2 arom. H); 7.28 ± 7.24 (m, 2 arom. H); 7.17 (BB' of
AA'BB', J ˆ 8.1, 2 arom. H); 7.08 (BB' of AA'BB', J ˆ 8.2, 2 arom. H); 7.00 ± 6.96 (m, 3 arom. H); 3.80 (s with
satellite, J ˆ 6.3, CH2Se); 3.51 (t, J ˆ 4.6, 2 CH2O); 3.44 (t, J ˆ 4.6, 2 CH2N); 2.42 (s, Me). 13C-NMR: 159.0,
150.1, (2s, SeCN2, CN2); 148.3, 143.5, 140.7, 133.9, 110.8 (5s, 5 arom. C); 132.1, 129.4, 128.8, 128.4, 127.9, 122.6,
122.3 (7d, 13 arom. C); 118.5 (s, CꢀN); 66.3 (t, 2 CH2O); 48.9 (t, 2 CH2N); 30.7 (t, CH2Se); 21.4 (q, Me). CI-
‡
MS: 503 (100, [M ‡ 1] ), 388 (90), 308 (81). Anal. calc. for C27H26N4OSe (501.49): C 64.67, H 5.19, N 11.18;
found: C 64.57, H 5.36, N 11.21.
Ethyl 2-[({[(4-chlorophenyl)(phenylimino)methyl]imino}(morpholin-4-yl)methyl)selanyl]acetate (11e).
From 5.05 mmol of 7j and ethyl 2-bromoacetate: 2.17 g (87%). M.p. 108.5 ± 1098 (Et2O). IR: 2957m, 2922w,
2848w, 1730s, 1606s, 1576s, 1487m, 1444m, 1425w, 1395m, 1365w, 1301m, 1287m, 1263s, 1194m, 1163m, 1112s,
1092m, 1057m, 1018s, 1012s, 1001m. 1H-NMR: 7.93, 7.38( AA'BB', J ˆ 8.7, 4 arom. H); 7.30 ± 7.23 (m, 2 arom. H);
7.02 ± 6.95 (m, 3 arom. H); 4.02 (q, J ˆ 7.1, MeCH2O); 3.54 (t, J ˆ 4.6, 2 CH2O); 3.43 (t, J ˆ 4.5, 2 CH2N); 3.25 (s
with satellite, J ˆ 6.3, CH2Se); 1.16 (t, J ˆ 7.1, Me ) . 13C-NMR: 169.3 (s, CO); 157.6, 149.7 (2s, SeCN2, CN2);
149.3, 136.5, 135.0 (3s, 3 arom. C); 129.4, 128.3, 128.2, 122.8, 122.1 (5d, 9 arom. C); 66.3 (t, 2 CH2O); 61.6
‡
(t, MeCH2O); 48.9 (t, 2 CH2N); 27.2 (t, CH2Se); 13.9 (q, Me). CI-MS: 494 (28, [M ‡ 1] ), 401 (34), 328(51), 94
(100). Anal. calc. for C22H24ClN3O3Se (492.87): C 53.61, H 4.90, Cl 7.19, N 8.53; found: C 53.41, H 5.02, Cl 7.35,
N 8.53.
N1-{[(Cyanoethyl)selanyl][(methyl)(phenyl)amino]methylidene}-4-methyl-N2-phenylbenzimidamide (11f).
From 1.5 mmol of 7i and 3-bromopropionitrile: 0.59 g (85%). M.p. 144.2 ± 144.58 (Et2O). IR: 3064w, 2995w,
2934w, 2253w, 1601s, 1587s, 1556s, 1508m, 1492s, 1446m, 1412m, 1340m, 1306w, 1286w, 1257s, 1210m, 1187w,
1169m, 1116m, 1074w, 1023m. 1H-NMR: 7.96 (d-like, 2 arom. H); 7.35 (t-like, 2 arom. H); 7.29 ± 7.22
(m, 5 arom. H); 7.12 ± 7.03 (m, 3 arom. H); 6.74 ± 6.71 (m, 2 arom. H); 3.17 (s, MeN); 2.78, 2.51 (2t, 2 CH2);
2.42 (s, Me). 13C-NMR: 157.7, 150.3 (2s, SeCN2, CN2); 150.0, 143.8, 140.9, 133.9 (4s, 4 arom. C); 129.2, 129.0,
128.7, 128.1, 127.8, 122.6, 122.0 (7d, 14 arom. C); 118.6 (s, CꢀN); 41.2 (q, MeN); 22.3, 18.7 (2t, 2 CH2); 21.4
‡
(q, Me). CI-MS: 461 (100, [M ‡ 1] ), 406 (13), 343 (17), 328(50). Anal. calc. for C 25H24N4Se (459.46): C 65.36,
H 5.23, N 12.20; found: C 65.29, H 5.40, N 12.08.
7. Preparation of 1,3-Selenazoles 12. To a soln. of an ethyl 1,3-selenazole-5-carboxylate in acetone, an aq.
soln. of NaOH (5%) was added (2 ± 3 equiv. of NaOH). Then, acetone was added to obtain a homogenous soln.,
and the mixture was heated under reflux. After 2 h, the starting material was consumed (TLC), the mixture was
poured into ice/H2O, and the product was isolated by filtration.
4-[4-(4-Methylphenyl)-1,3-selenazol-2-yl]morpholine (12a). From 2.5 mmol of 9l: 0.54 g (71%). M.p.
82.5 ± 83.58. IR: 3100w, 3031w, 2977w, 2921m, 2871m, 2839m, 1538s, 1489m, 1447m, 1434m, 1371m, 1319m,
1297m, 1278m, 1225s, 1197w, 1177m, 1114s, 1074w, 1043m, 1021m. 1H-NMR: 7.72, 7.15 (AA'BB', J ˆ 4 arom. H);
7.29 (s with satellite, J ˆ 25.7, HÀC(5)); 3.81 (t, J ˆ 4.9, 2 CH2O); 3.52 (t, J ˆ 4.9, 2 CH2N); 2.34 (s, Me).
13C-NMR: 172.9, 152.8(2 s, C(2), C(4)); 137.1, 133.0 (2s, 2 arom. C); 129.1, 126.2 (2d, 4 arom. C); 105.0 (d, C(5));
‡
66.2 (t, 2 CH2O); 49.6 (t, 2 CH2N); 21.1 (q, Me). CI-MS: 309 (100, [M ‡ 1] ), 290 (20), 94 (27). Anal. calc. for
C14H16N2OSe (307.26): C 54.72, H 5.21, N 9.12; found: C 54.94, H 5.20, N 9.18.

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4-(4-Chlorophenyl)-N-methyl-N-phenyl-1,3-selenazol-2-amine (12b). From 3.8mmol of 9s: 1.01 g (76%).
M.p. 137.7 ± 1398 (Et2O). IR: 3078w, 2988w, 2905w, 2886w, 1594w, 1582m, 1529s, 1500s, 1474s, 1397m, 1338m,
1318m, 1306m, 1286m, 1253s, 1174m, 1126w, 1083m, 1050m, 1032m, 1009m. 1H-NMR: 7.80, 7.31 (AA'BB', J ˆ 8.7,
4 arom. H); 7.45 ± 7.41 (m, 4 arom. H); 7.32 ± 7.25 (m, 1 arom. H); 7.18( s with satellite, J ˆ 24.6, HÀC(5)); 3.59
(q, MeN). 13C-NMR: 171.6, 151.4 (2s, C(2), C(4)); 147.3, 134.4, 132.8(3 s, 3 arom. C); 129.9, 128.5, 127.5, 126.8,
‡
125.1 (5d, 9 arom. C); 106.0 (d, C(5)); 40.3 (q, MeN). CI-MS: 349 ([M ‡ 1] ). Anal. calc. for C16H13ClN2Se
(347.70): C 55.27, H 3.77, Cl 10.20, N 8.06; found: C 55.27, H 3.83, Cl 10.40, N 8.05.
8. Crystal-Structure Determination of 7f, 9c, and 9d (see Table 4, and Figs. 1 and 3)14). All measurements
were performed on
a Rigaku AFC5R diffractometer with graphite-monochromated MoKa radiation
(l 0.71069 Š) and a 12-kW rotating anode generator. The w/2q scan mode was employed for data collection.
The intensities were corrected for Lorentz and polarization effects, and an empirical absorption correction
based on y scans was applied in the cases of 7f and 9d [37], whereas, in the case of 9c, an empirical absorption
correction by means of the program DIFABS [38] was applied. Data collection and refinement parameters are
given in Table 4, views of the molecules are shown in Figs. 1 and 3. The structures were solved by direct methods
Table 4. Crystallographic Data of Compounds 7f, 9c, and 9d
7f
9c
9d
Crystallized from
acetone
C19H21N3OSe
386.29
yellow, prism
0.17 Â 0.40 Â 0.43
173(1)
EtOH
C23H17N3O3Se
462.30
yellow, irregular prism
0.20 Â 0.33 Â 0.45
173(1)
acetone
C22H22N2O2Se
425.33
pale yellow, prism
0.25 Â 0.32 Â 0.40
173(1)
Empirical formula
Formula weight [g molÀ1
Crystal color, habit
Crystal dimensions [mm]
Temperature [K]
]
Crystal system
Space group
monoclinic
P21/c
monoclinic
P21/c
monoclinic
P21/c
Z
4
4
4
Reflections for cell determination
25
25
25
2q Range for cell determination [8]
39 ± 40
24 ± 26
39 ± 40
Unit-cell parameters a [Š]
8.982(3)
13.577(4)
14.726(2)
104.24(2)
1740.5(7)
1.474
12.594(1)
14.834(3)
10.986(2)
102.26(1)
2005.5(6)
1.531
10.229(5)
9.765(4)
19.784(4)
103.30(3)
1923(1)
1.469
b [Š]
c [Š]
b [8]
V [Š3]
Dx [g cmÀ3
]
m(MoKa) [mmÀ1
2q(max) [8]
]
2.167
55
1.902
55
1.971
55
Transmission factors (min; max)
Total reflections measured
Symmetry-independent reflections
Reflections used [I > 2s(I)]
Parameters refined
0.491; 0.692
4434
4003
2996
302
0.485; 0.683
5026
4604
31483296
340
0.511; 0.611
4934
4417
333
Final R
0.0345
0.0282
0.0445
0.0388
0.0332
0.0278
wR (w ˆ [s2(Fo) ‡ (0.005Fo)2]À1
Goodness of fit
Secondary extinction coefficient
Final Dmax/s
D1 (max; min) [e Š
1.460
1.920
1.434
1.6(4) Â 10À7
6(5) Â 10À8
3.7(3) Â 10À7
0.001
0.0004
0.0006
À3
]
0.39; À0.480.66;
À0.55
0.39; À0.38
14
)
Crystallographic data (excluding structure factors) for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data Centre as supplementary publications No. CCDC-
141338± 141340 for 7b, 9c, and 9d, respectively. Copies of the data can be obtained, free of charge, on
application to the CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax: ‡44-(0)1223-336033 or e-mail:
deposit@ccdc.cam.ac.uk).

Helvetica Chimica Acta ± Vol. 83 (2000)
1597
using SIR92 [39], which revealed the position of all non-H-atoms. The non-H-atoms were refined anisotropi-
cally. All of the H-atoms were located in difference electron-density maps, and their positions were allowed to
refine together with individual isotropic displacement parameters. Refinement of each structure was carried out
on F using full-matrix least-squares procedures, which minimized the function Sw(j Fo jÀj Fc j )2. A correction for
secondary extinction was applied. Neutral-atom scattering factors for non-H-atoms were taken from [40a] and
the scattering factors for H-atoms from [41]. Anomalous dispersion effects were included in Fc [42]; the values
for f ' and f '' were those of [40b], and the values of the mass-attenuation coefficients were those of [40c]. All
calculations were performed using the teXsan crystallographic software package [43].
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Received March 22, 2000