Reaction of α-iminomethylene amino esters with mono- and bidentate nucleophiles: A straightforward route to 2-amino-1H-5-imidazolones

Article abstract of DOI:10.1016/S0040-4020(01)00330-1

The reaction between α-iminomethylene amino esters with different mono- and bidentate nucleophiles has been studied. It has been shown that the reactions with primary and secondary amines as monodentate nucleophiles afford 2-aminoimidazolones efficiently under very mild conditions. Judicious selection of the primary amines employed can modulate the regioselectivity. Analogous reactions employing bidentate nucleophiles (e.g. amidines) also afford imidazolyl derivatives. The formation of the latter is preferred over the formation of seven-membered heterocycles of the triazepinone type. The optimized methodology in solution described herein should be readily adaptable to use in the solid phase for the parallel synthesis of collections of 2-aminoimidazolone derivatives with a high degree of molecular diversity.

Full text of DOI:10.1016/S0040-4020(01)00330-1

TETRAHEDRON
Pergamon
Tetrahedron 57 .2001) 4371±4388
Reaction of a-iminomethylene amino esters with mono- and
bidentate nucleophiles: a straightforward route to
2-amino-1H-5-imidazolones
a,²
Montserrat Heras, Montserrat Ventura, Anthony Linden and Jose M. Villalgordo
a
b
a,p
Â
a
 Á
Departament de Quõmica, Facultat de Ciencies, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Spain
b
È È È
Organisch-chemisches Institut der Universitat Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
Received 4 December 2000; revised 22 February 2001; accepted 22 March 2001
AbstractÐThe reaction between a-iminomethylene amino esters with different mono- and bidentate nucleophiles has been studied. It has
been shown that the reactions with primary and secondary amines as monodentate nucleophiles afford 2-aminoimidazolones ef®ciently under
very mild conditions. Judicious selection of the primary amines employed can modulate the regioselectivity. Analogous reactions employing
bidentate nucleophiles .e.g. amidines) also afford imidazolyl derivatives. The formation of the latter is preferred over the formation of seven-
membered heterocycles of the triazepinone type. The optimized methodology in solution described herein should be readily adaptable to use
in the solid phase for the parallel synthesis of collections of 2-aminoimidazolone derivatives with a high degree of molecular diversity.
q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
activity against murine P388 lymphocytic leukaemia,8 or
leucettamine B and the mauritiamines, isolated from the
marine sponges Leucetta microraphis and Agelas
mauritiana, respectively, which show potent anti-
in¯ammatory and antifouling activities.9,10 For several of
these alkaloids, their total synthesis has also been
reported.11±14
2-Aminoimidazolones of type 1 .Fig. 1) represent an
interesting pharmacophore that displays a wide variety of
biological properties. Synthetic compounds containing this
structural motif have been shown, for instance, to exert a
potent hypoglycaemic1±4 and hypotensive activity.5 In
addition, in the last few years, an increasingly important
number of alkaloids isolated from marine organisms have
been reported to bear the 2-aminoimidazolone moiety.6
Examples of these include the discapamides, isolated from
Caribbean Agelas sponges, of which some members show a
potent antihistamine activity,7 the hymenialdisines, isolated
from various Agelasidae sponges and exhibiting potent
During the course of our ongoing studies dealing with the
development of ef®cient methodologies that could readily
be adapted for combinatorial and/or parallel synthesis, in
solution and/or on solid supports, of relevant core structures
with potential therapeutic interest,15±18 we focused our
attention on the 2-aminoimidazolone nucleus 1. We wished
to identify and to develop an ef®cient methodology that
could afford collections of 2-aminoimidazolones of type 1
with a high degree of molecular diversity. This method-
ology should also be readily adaptable to use in the solid
phase, taking full advantage of automated parallel synthesis
systems. From the several methods available and described
in the literature19±23 for the synthesis of targets of type 1, we
needed to use a strategy that could employ readily available
starting materials, and that in addition could be tethered to a
solid support. Furthermore, this strategy should allow the
introduction of a high degree of molecular diversity in each
step by using easily available building blocks. Finally, the
construction of the ®ve-membered cyclic guanidines of type
1 should be performed in the last step through a cyclization
process under mild conditions. This last requirement is of
special signi®cance when carried out on solid supports.
Procedures for cyclization-assisted cleavage are largely
Figure 1.
Keywords: a-carbodiimide esters; mono- and bidentated nucleophiles;
heterocyclization; 2-aminoimidazolones.
Corresponding author. Fax: 134-972-41-81-50;
e-mail: jose.villalgordo@udg.es
Taken in part from the PhD Thesis of M. H., Universitat de Girona, 1999.
p
²
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020.01)00330-1

4372
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
independent of the nature of the linker and offer several
advantages. For example, only molecules that have gone
through the whole reaction sequence necessary for the
cyclization reaction will be cleaved, and even if single
steps do not proceed quantitatively, the cyclization will
nevertheless lead to pure products. In addition, the ®nal
products do not contain any residue or ªmemoryº due to
the solid support.24
this iminophosphorane chemistry and with the aim of
establishing reliable reaction conditions in solution for the
preparation of our targets of type 1, which could eventually
be adapted to the solid phase, we were prompted to pursue this
study and the full details and scope are reported herein.
2. Results and discussion
Under the same premises, we recently disclosed the
2.1. Synthesis of a-iminomethylene amino esters 7a±c
successful solid-phase synthesis of
a
library of
3H-quinazolinones.15 This method, based on the formation
of carbodiimide esters derived from anthranilic acid
derivatives via an aza Wittig reaction, had previously
been very well documented in the literature.25,26 In fact,
the use of iminophosphoranes as intermediates in organic
synthesis have proven to be particularly useful for the
preparation of different six-membered heterocyclic systems
containing an endocyclic CyN double bond.26±31
Surprisingly, however, the application in solution of similar
methodologies for the synthesis of heterocycles in the ®ve-
membered series has been far less explored and little
experimental data are available.32±34 Therefore, based on
Consistent with this goal, the readily available a-bromo
esters 2a±c were selected as starting materials. Their
reaction with NaN3 in MeCN at r.t. for 20±48 h, afforded
after isolation by distillation under reduced pressure, the
corresponding a-azido esters 3a±c in good yields
.78±90%) as shown in Scheme 1.
The subsequent Staudinger reaction of a-azido esters 3 with
Ph3P at 08C in anhydrous CH2Cl2, led after 8 h to the
corresponding iminophosphoranes 4. Although the evolu-
tion of N2 could be clearly detected in these reactions, and
the disappearance of 3 could be properly monitored by TLC
or GC, the iminophosphoranes 4 proved to be too labile to
be isolated either by crystallization or by ¯ash-
chromatography. In all cases, only hydrolysed a-amino
esters of type 5 together with phosphine oxide 6 could be
isolated. In a second set of experiments, we moved directly
toward the target carbodiimides 7 in a one-pot procedure
simply by reacting in situ the previously formed imino-
phosphoranes 4 with 1 equiv. of phenyl isocyanate in
anhydrous CH2Cl2. After 2h at r.t., total consumption of
the starting materials was observed and the desired a-imino-
methylene amino ester derivatives 7 were isolated in pure
Scheme 1.
Scheme 2.
form and in good yields .56±75%, two steps, overall yield;
see Scheme 2and Table 1).
Table 1. Prepared a-iminomethylene amino esters 7a±c
Entry
Compound
R
Yield .%)a
m.p. .8C):
Having established a simple and reproducible procedure for
the ef®cient generation of carbodiimides of type 7, we then
proceeded further by ®rstly investigating the reactivity of
these types of substrates in the presence of monodentated
nucleophiles .e.g. primary and secondary amines).
1
2
3
7a
7b
7c
Me
Et
Ph
65
56
75
Colourless oil
Colourless oil
48±49
a
Overall yields .two steps) for isolated pure products.

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4373
Scheme 3.
2.2. Reaction with monodentated primary amines
n-propyl amine .8a and 8b, respectively) were allowed to
react with carbodiimide esters 7a±c in anhydrous THF at r.t.
for a period of 5±15 h, regioselective cyclization with the
formation of derivatives of type 10 took place and 2-phenyl-
amino imidazolones 10a±f were isolated in good yields
.75±89%). However, the analogous reaction with t-butyl
amine 8c promoted the opposite regioselective cyclization
affording exclusively 2-t-butylamino imidazolones 11a±c,
also in good yields .68±75%). However, when aniline 8d
and 2,4-dimethoxy aniline 8e were employed as mono-
dentate nucleophiles, no reaction occurred at r.t. and only
the formation of decomposition products was observed
when the reaction conditions were forced .Scheme 4 and
Table 2).
As can be seen in Scheme 3, the reaction between carbodi-
imides 7 and primary amines 8 should afford primarily
guanidine intermediates of type 9. From these intermediates
9, the formation of two regioisomeric 2-aminoimidazolones
.10 and/or 11) could in principle take place. 2-Amino-
imidazolones of type 10 will be the resulting products
after a subsequent nucleophilic attack from the intervening
amine over the carbonyl ester .pathway a). Regioisomeric
2-aminoimidazolones of type 11 will be formed instead
when the heterocyclization reaction is a result of the attack
of the former carbodiimidic nitrogen atom .pathway b). The
ratio of the formed imidazolones of type 10 and 11 will
depend presumably on the electronic and/or the steric
factors exerted by the two amine groups in intermediates
of type 9.
These results indicate that in this type of transformation,
regioselectivity toward the formation of 10 and/or 11
seems to be in¯uenced not only by differences in the nucleo-
philic character of the two nitrogen atoms of the guanidine
Accordingly, when primary amines like benzyl- and
Scheme 4.

4374
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
Table 2. Synthesized 2-aminoimidazolones of type 10 and 11
R1±NH2
Entry
R
Compound
Reaction time .h)
Yield .%)a
m.p. .8C):
i
ii
iii
Me
Et
Ph
10a
10b
10c
6
5
8
86
84
88
Colourless oil
Colourless oil
129±130
iv
v
vi
Me
Et
Ph
10d
10e
10f
15
15
1289
76
75
135±136
Colourless oil
Colourless oil
dec.
vii
viii
ix
Me
Et
Ph
11a
11b
11c
15
15
15
68
75
59±60
73±74
0
72119±12
dec.
x
Me
Et
NRb
NR
±
±
±
±
±
xi
±
a
Yields of isolated pure products.
No reaction.
b
intermediates of type 9, but also by the steric factors
involved. Thus, when nucleophilic, non-sterically hindered
primary amines were used, 2-aminoimidazolones of type 10
were formed .entries i±vi in Table 2). However, when large
steric restrictions are present in intermediates of type 9, this
effect predominates over any nucleophilic character and the
opposite regioselectivity is obtained giving rise to the
exclusive formation of 2-aminoimidazolones of type 11
.entries vii±ix in Table 2).
mixtures of 10g±i and 11d±f in different ratios .Scheme 5
and Table 3).
The structure of regioisomeric 2-aminoimidazolones of type
10 and 11 could be unambiguously established with the help
of X-ray crystal structure analyses. Initially, we attempted to
obtain crystals of adequate quality from 11c by slow
evaporation of a CH2Cl2 solution at r.t. Surprisingly,
however, and presumably as a consequence of the slow
crystallization process, 11c dimerized into 12 as found
afterwards from the subsequent X-ray diffraction analysis
Using these arguments, it should also be possible to ®nd
Scheme 5.
Table 3. Synthesized 2-aminoimidazolones from 7a±c and 8f
cases in which neither the nucleophilicity of the two guani-
dinic nitrogen atoms, nor the steric demand imposed in
intermediates of type 9, clearly predominate, and that
mixtures of regioisomeric 2-aminoimidazolones 10 and 11
should then be obtained.
R
Entry Compound Reaction time .h) Yield .%)a m.p. .8C):
Me
Et
1
2
3
4
5
6
10g
11d
10h
11e
10i
15
15
15
15
15
15
65
15
35
35
70
±
90±91
118±119
91±92
120±121
154±155dec.
±
Ph
Indeed, this was effectively the case when isopropyl amine
8f was employed as the monodentate nucleophile. In this
case, despite the nucleophilic power of the aliphatic
nitrogen atom, the steric effect exerted by the isopropyl
group in intermediates of type 9 allowed the formation of
11fb
a
Yields of isolated pure products.
Compound detected by TLC but decomposes during the puri®cation
process.
b

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4375
Figure 2. Dimerization of 11c during crystallization.
Figure 3. Ortep plot of the molecular structure of 12 with 50% probability ellipsoids.35
.Figs. 2and 3). The dimerization mechanism to 12, probably
involving a radical and/or oxidation pathway was not fully
investigated at this stage.
Although the crystal obtained did not correspond to the
expected 11c, the structure of the dimer 12 accounted for
the mentioned regioselectivity. In addition, we were able to
obtain crystals of 10g and 11e that were of adequate quality
and these were also used for X-ray crystal structure
analyses, which con®rmed the proposed structures and
regioselectivity .Figs. 4 and 5). Subsequent correlation of
the spectroscopic data allowed for consistent structural
elucidation of all synthesized 2-aminoimidazolones of
types 10 and 11.
Interestingly, as can be seen in Fig. 4, compound 10g
crystallized in another tautomeric form .10g0) with the
CyN double bond exo to the ®ve-membered ring, and the
ring N-atom being the protonated amine group .Fig. 6).
Therefore, as has been shown, the reaction between
a-iminomethylene amino esters of type 7 and amines 8
can lead under mild conditions via guanidine inter-
mediates of type 9 .Scheme 3) to different regio-
isomeric imidazolones of type 10 and/or 11 depending
Figure 4. Ortep plot of the molecular structure of 10g0 with 50% prob-
ability ellipsoids.35 Bond length of C.3)ZN.3)ˆ1.270 .4) A .correspond-
Ê
Ê
ing to a CyN double bond). Bond length of C.3)ZN.4)ˆ1.363 .4) A
.corresponding to a CZN single bond).

4376
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
on the nature of the primary amine employed, although
it is possible to predict to some extent the kind of
derivative obtained.
2.3. Reaction with monodentate secondary amines
A much simpler picture should be expected, however, when
the same type of reaction is carried out employing
secondary amines as monodentate nucleophiles. In these
cases, only one mode of cyclization is available, which is
independent of the steric requirements imposed by the
intervening amine.
Effectively, when a solution of carbodiimides 7a±b in
anhydrous THF were allowed to react with different
secondary amines of type 13 for a period of 15±18 h, the
corresponding 2-amino imidazolones of type 15 were
isolated in excellent yields .79±98%, Scheme 6 and
Table 4).
Special mention should be made of the reaction involving
the carbodiimide ester 7c. Its reaction with secondary
amines 13a±c proceeded as usual but the ®nal products
were rather unstable. They could not be isolated by ¯ash-
chromatography due to fast decomposition, and only 15h
could be isolated in 79% yield by crystallization from
CH2Cl2:ether:n-pentane. 2-Aminoimidazolones 15g and
15i, when subjected to the same crystallization work-up
dimerized into 16 and 17, respectively, and were isolated
in 75±77% yields .Scheme 7).
Figure 5. Ortep plot of the molecular structure of 11e with 50% probability
ellipsoids.35
2.4. Reaction with bidentate amidines
Having established the general behaviour of a-imino-
methylene amino esters of type 7 in the presence of
Figure 6.
Scheme 6.
Table 4. Synthesized imidazolones 15a±f
R1R2NH
Entry
R
Reaction time .h)
Compound
Yield .%)
m.p. .8C):
1
Me
15
15a
15b
88
98
63±64
2Et
15
Colourless oil
3
4
Me
Et
18
18
15c
15d
80
79
96±97
Colourless oil
5
6
Me
Et
18
18
15e
15f
92Colourless oil
96
Colourless oil

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4377
Scheme 7.
monodentate nucleophiles .primary and secondary amines),
we wished to study further their synthetic potential. In
particular, we were interested in examining their reactivity
with bidentate nucleophiles of the amidine type.
20 took place. No traces of imidazolones of the general
type 21 or triazepinones of type 22 were detected.
These derivatives 20, could be isolated in pure form
and in generally good yields .48±78%) after a simple
chromatographic ®ltration, except those derived from
carbodiimide 7c, which proved to be too unstable and
decomposed rapidly. However, for this particular case,
by slightly changing the reaction conditions .DIPEA as
a base in MeCN), it was possible to isolate 20i and 20j,
although in low yields .35% and 20%, respectively; see
Scheme 9 and Table 5).
a-Iminomethylene amino esters 7 can be catalogued as
1,4-bis-acceptor building blocks .or 1,4-dielectrophiles),
and amidines 18 can be catalogued as 1,3-bis-donor
building blocks .or 1,3-dinucleophiles). Therefore, the
combination of both 7 and 18, could lead via guanidine
intermediates of type 19, not only to imidazolones of
general structure 20 .pathway a) or 21 .pathway b) but
also to seven-membered heterocycles of the triazepinone
type 22 .pathway c) .Scheme 8).
The structural elucidation of imidazolones of type 20 was
accomplished on the basis of the usual spectroscopic
methods. As shown in Fig. 7, it is also possible to write
other tautomeric forms .200 and 2000) of the involved
exocyclic guanidine moiety.
With the aim of disclosing the general trend followed in
this type of reaction, several easily available amidines
18a±d were selected and their reactions with carbodi-
imide esters 7a±c were studied. We found that when a
solution of the corresponding carbodiimides 7a±c in
anhydrous MeCN was treated with amidines 18a±d in
the presence of 2equiv. of solid K 2CO3 at r.t., the
exclusive formation of 2-amino imidazolones of type
The data obtained from the 1H-NMR spectra taken in CDCl3
or DMSO-d6 solutions of the synthesized 20a±j, did not
provide enough evidence for the preferred tautomeric
form. The presence of two distinct D2O exchangeable
protons revealed the presence of two different NH groups,

4378
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
Scheme 8.
but since the two hydrogen atoms of 200 could be placed in
distinctly different environments due to the ¯at structure of
its imidate moiety, none of the above-represented tautomers
should a priori be neglected. In order to obtain more data
about this point, 20e was subjected to an X-ray crystal
structure analysis, which showed that the preferred
tautomeric form in the solid state corresponds with that
represented by the general formula 200 as shown in Figs.
7 and 8.
3. Conclusions
In summary, we have shown that 1,4-bis-aceptor a-imino-
methylene amino esters of type 7, easily available from
a-bromo esters 2, are good synthetic precursors for the
preparation of imidazolyl derivatives. Their reactions with
monodentate nucleophiles furnish under very mild
conditions and in good yields collections of 2-amino-
imidazolones of the type 10 and/or 11. The regioselection
Scheme 9.
Table 5. Prepared 2-aminoimidazolones 20a±j
R
R1
Entry
Base
Reaction Time .h)
Compound
Yield .%)
m.p. .8C):
Me
PhCH2S
CH3.CH2)9S
Ph
1
2
3
4
5
6
7
8
9
10
K2CO3
2CO3
6
20a
20b
20c
20d
20e
20f
20g
20h
20i
69
65
48
68
75
78
56
65
35
20
143±144
68±69
132±133
151±152
144±145
73±74
139±140
160±161
113±114dec.
165±166dec.
K
18
18
15
8
18
20
8
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
DIPEA
DIPEA
Me
Et
PhCH2S
CH3.CH2)9S
Ph
Me
CH3.CH2)9S
Me
Ph
6
15
20j

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4379
Figure 7.
Figure 8. Ortep plot of the molecular structure of 20e0 with 50% probability ellipsoids.35
issue concerning the use of primary amines as nucleophiles
can be modulated by the judicious selection of their electro-
nic and/or the steric properties. Thus, when nucleophilic,
non-sterically hindered primary amines are used, exclusive
regioselective transformation toward derivatives of type 10
can be obtained. In turn, nucleophilic amines bearing groups
with a large steric demand will promote the opposite
regioselection, giving rise to 2-aminoimidazolones of type
11. By using secondary amines as monodentate
nucleophiles, only 2-aminoimidazolones of type 11 will
be formed, without any dependence on steric factors. The
structures of the 2-aminoimidazolones of type 10 and 11
were established unambiguously from the X-ray crystal
structure analyses of some representatives and a correlation
of their spectroscopic data with all other synthesized
derivatives.
The methodology presented herein should be readily
adaptable to the solid phase. The coupling of easily
available a-bromo acids .of which a good number is already
commercially available) to hydroxymethyl polystyrene
resin should provide the ®rst synthetic precursor in analogy
to 2a±c. Following an analogous synthetic sequence, the
reaction of polymer-bound carbodiimide esters with
different secondary amines and amidines should lead in a
highly regioselective manner to collections of imidazolones
via a cyclization-assisted cleavage with the concomitant
release from the solid support. Preliminary experiments
along this line have been performed successfully and the
results will be published in due course.
4. Experimental
4.1. General
Finally, when bidentate nucleophiles like amidines 18a±d
were allowed to react with carbodiimide esters 7a±c at r.t.
imidazolyl derivatives of type 20 were formed in a highly
regioselective manner. Despite the nucleophilic character of
the nitrogen atoms in intermediates of type 19, the
formation of the ®ve-membered heterocycles 20 was largely
preferred over the seven-membered derivatives of type 22.
All commercially available chemicals were used as
purchased. MeCN was dried over activated molecular sieves
Ê
.4 A). THF was dried over Na/benzophenone prior to use.
All reactions were run under a positive pressure of dry N2.
Melting points .capillary tube) were measured with an

4380
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
Electrothermal digital melting point apparatus IA 9100 and
are uncorrected. IR spectra were recorded on a Mattson-
1391, 1370, 1335, 1300, 1257, 1197, 1178, 1096, 1026, 913,
878, 842, 779, 730, 702 cm21. MS .FAB1) m/e: 2 06
.[M11]1, 6), 205 .M1, 1), 178 .44), 164 .14), 163 .27),
137 .27), 136 .15), 135 .16), 132 .15), 107 .22), 106 .26),
105 .23), 104 .100). Anal. Calc. for C10H11N3O2 .205.21):
C 58.53%, H 5.40%, N 20.48. Found: C 58.34%, H 5.19%,
N 20.74%.
1
Galaxy Satellite FT-IR. H and 13C NMR spectra were
recorded at 200 and 50 MHz, respectively, on a Brucker
DPX200 Advance instrument with TMS as internal
standard. MS spectra were recorded on a VG Quattro
instrument in the positive ionization FAB mode, using
3-NBA or 1-thioglycerol as the matrix. Elemental analyses
were performed on an apparatus from Thermo instruments,
model EA1110-CHNS. Analytical TLC was performed on
precoated TLC plates, silica gel 60 F254 .Merck). Flash-
chromatography puri®cations were performed on silica gel
60 .230±400 mesh, Merck).
4.3. Synthesis of a-iminomethylene amino ester derivatives
7a±c. General procedure
To a cooled .08C) solution of 10 mmol .1 equiv.) of the
corresponding a-azido esters 3a±c in 30 mL of dry
CH2Cl2, 10 mL .10 mmol, 1 equiv.) of a 1 M solution of
Ph3P in dry CH2Cl2 were added dropwise. A vigorous N2
gas evolved immediately. The reaction mixture was stirred
under a positive pressure of dry Ar from 08C to r.t. for 8 h.
Then 1.09 mL .10 mmol, 1 equiv.) of phenylisocyanate were
added, and the new reaction mixture stirred at r.t. under Ar for
an additional 2h. The solvent was eliminated under reduced
pressure and the resulting residue puri®ed by ¯ash-chromato-
graphy .n-hexane:AcOEt) to afford pure 7a±c.
4.2. Synthesis of a-azidoesters 3a±c. General procedure
To a suspension at r.t. of sodium azide .2.92 g, 45 mmol,
2.5 equiv.) in 72 mL of dry MeCN, the corresponding
a-bromo esters 2a±c .18 mmol, 1 equiv.) were added. The
reaction mixture, under N2, was stirred at r.t. for 20±48 h.
The reaction mixture was ®ltered over a celite pad, the
organic solvent eliminated under reduced pressure and the
residue distilled bulb to bulb in vacuo.
4.3.1. Ethyl 2-phenyliminomethyleneaminopropanoate
07a). According to the general procedure described above,
the reaction between 3a and phenyl isocyanate afforded
4.2.1. Ethyl 2-azidopropanoate 03a). According to the
general procedure described above, the reaction between
2a and sodium azide afforded 2.0 g .78%) of 3a as a colour-
less oil. B.p.: 50±528C .0.1 Torr); 1H NMR .CDCl3): d 1.29
.t, 3H, Jˆ7 Hz, CH3), 1.48 .d, 3H, Jˆ7.1 Hz, CH3), 3.9 .q,
1H, Jˆ7.1 Hz), 4.25 .q, 2H, Jˆ7 Hz, OCH2CH3). 13C NMR
.CDCl3): d 14.51 .q, CH3CH2), 17.13 .q, CH3CH), 57.74
.d,CH), 62.19 .t, OCH2CH3), 171.38 .s, CO). IR .®lm)
n 2981, 2933, 2881, 2120, 1744, 1450, 1381, 1334, 1299,
1258, 1197, 1094, 1019, 901, 850 cm21. MS .FAB1) m/e:
144 .[M11]1, 100). Anal. Calc. for C5H9N3O2 .143.14):
C 41.95%, H 6.34%, N 29.36. Found: C 42.23%, H 6.21%,
N 29.07%.
1
0.86 g .65%) of 7a as a colourless oil. H NMR .CDCl3):
d 1.3 .t, 3H, Jˆ7.2Hz, C H3), 1.59 .d, 3H, Jˆ7.0 Hz, CH3),
4.18 .q, 1H, Jˆ7.0 Hz, CH), 4.21 .q, 2H, Jˆ7.2Hz, OC H2),
7.35±7.15 .m, 5H, Harom.). 13C NMR .CDCl3): d 14.02
.q, CH3), 20.24 .q, CH3), 55.05 .d, CH), 61.84 .t, OCH2),
123.91 .d, 2CHarom.), 124.94 .d, CHarom.), 129.18
.d, 2CHarom.), 137.31 .s, Carom.), 139.43 .s, ZNyCyNZ),
171.82.s, CO). IR .®lm) n 3063, 2988, 2942, 2890, 2130,
1739, 1593, 1502, 1450, 1375, 1293, 1257, 1205, 1158,
1097, 1075, 1018, 899, 871, 850, 757, 690 cm21. MS
.FAB1) m/e: 219 .[M11]1, 20), 218 .M1, 9), 191 .10),
146 .11), 145 .100), 120.10), 119 .13). Anal. Calc. for
C12H14N2O2 .218.25): C 66.04%, H 6.47%, N 12.84.
Found: C 65.77%, H 6.67%, N 12.55%.
4.2.2. Ethyl 2-azidobutanoate 03b). According to the
general procedure described above, the reaction between
2b and sodium azide afforded 2.26 g .80%) of 3b as a
colourless oil. B.p.: 60±658C .0.1 Torr). 1H NMR
.CDCl3): d 0.99 .t, 3H, Jˆ7.4 Hz, CH3), 1.29 .t, 3H,
Jˆ7.2Hz, C H3), 1.70±1.90 .m, 2H, CH2), 3.75 .dd, 1H,
Jˆ7.7 Hz, J0ˆ5.6 Hz, CH), 4.28 .q, 2H, Jˆ7.2Hz,
OCH2CH3). 13C NMR .CDCl3): d 9.97 .q, CH3), 13.95 .q,
CH3), 24.68 .t, CH2), 61.47 .d, CH), 63.14 .t, OCH2), 170.29
.s, CO). IR .®lm) n 2979, 2938, 2882, 2108, 1743, 1461,
4.3.2. Ethyl 2-phenyliminomethyleneaminobutanoate
07b). According to the general procedure described above,
the reaction between 3b and phenyl isocyanate afforded
1
0.94 g .50%) of 7b as a colourless oil. H NMR .CDCl3):
d 0.97 .t, 3H, Jˆ7.2Hz, C H3CH2), 1.19 .t, 3H, Jˆ7.1 Hz,
CH3), 1.75±1.90 .m, 2H, CH3CH2), 3.99 .dd, 1H,
Jˆ6.95 Hz, J0ˆ5.3 Hz, CH), 4.18 .q, 2H, Jˆ7.1 Hz,
OCH2), 7.0±7.25 .m, 5Harom.). 13C NMR .CDCl3): d 9.95
.q, CH3), 14.13 .q, CH3), 27.53 .t, CH2), 60.80 .t, OCH2),
61.81 .d, CH), 123.98 .d, 2CHarom.), 124.87 .d, CHarom.),
125.83 .s, Carom.), 129.25 .d, 2CHarom.), 139.68
.s, ZNyCyNZ), 171.29 .s, CO). IR .®lm) n 3063, 2974,
2933, 2878, 2140, 1737, 1593, 1457, 1368, 1342, 1293,
1251, 1204, 1183, 1156, 1103, 1082, 1018, 934, 850, 758,
688 cm21. MS .FAB1) m/e: 233 .[M11]1, 39), 232 .M1,
12), 205 .21), 194 .17), 172 .16), 160 .11), 159 .100), 144
.24), 120 .12), 119 .17). Anal. Calc. for C13H16N2O2
.232.28): C 67.22%, H 6.94%, N 12.06. Found: C 67.01%,
H 6.75%, N 12.21%.
1370, 1333, 1293, 1259, 1193, 1117, 1096, 1023, 899 cm21
.
MS .FAB1) m/e: 158 .[M11]1, 100). Anal. Calc. for
C6H11N3O2 .157.17): C 45.85%, H 7.05%, N 26.74.
Found: C 45.62%, H 7.22%, N 26.49%.
4.2.3. Ethyl 2-azido-2-phenylacetate 03c). According to
the general procedure described above, the reaction between
2c and sodium azide afforded 3.32g .90%) of 3c as a
colourless oil. B.p.: 80±828C .0.1 Torr). 1H NMR
.CDCl3): d 1.29 .t, 3H, Jˆ7.2Hz, C H3), 4.15 .q, 2H,
Jˆ7.2Hz, OC H2), 4.99 .s, 1H, CH), 7.44 .s, 5Harom.). 13C
NMR .CDCl3): d 13.91 .q, CH3), 62.03 .d, CH), 65.22 .t,
OCH2), 127.52 .d, 2CHarom.), 128.96 .d, 2CHarom.), 129.12
.d, CHarom.), 133.90 .s, Carom.), 169.0 .s, CO). IR .®lm)
n 3064, 6036, 2980, 2938, 2910, 2106, 1743, 1496, 1454,
4.3.3. Ethyl 2-phenyl-2-phenyliminomethyleneamino-
acetate 07c). According to the general procedure described

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4381
above, the reaction between 3c and phenyl isocyanate
afforded 2.10 g .75%) of 7c as a colourless solid. M.p.:
48±498C. 1H NMR .CDCl3): d 1.03 .t, 3H, Jˆ7.1 Hz,
CH3), 4.15 .q, 2H, OCH2), 4.97 .s, 1H, CH), 7.05±7.35
.m, 10Harom.). 13C NMR .CDCl3): d 9.95 .q, CH3), 62.75
.t, OCH2), 63.54 .d, CH), 124.63 .d, 2CHarom.), 125.59
.d, CHarom.), 127.47 .d, 2CHarom.), 129.15 .d, CHarom.),
129.33 .d, 2CHarom.), 129.74 .d, 2CHarom.), 136.49
.s, Carom.), 137.76 .s, Carom.), 139.16 .s, ZNyCyNZ),
170.11 .s, CO). IR .KBr) n 3063, 3030, 2984, 2938, 2896,
2129, 2105, 1734, 1592, 1502, 1440, 1377, 1327, 1307,
1204, 1174, 1154, 1075, 1023, 969, 934, 857, 835, 754,
723, 694 cm21. MS .FAB1) m/e: 281 .[M11]1, 37), 280
.M1, 8), 207 .28), 164 .12), 163 .100), 135 .7). Anal. Calc.
for C17H16N2O2 .280.32): C 72.84%, H 5.75%, N 9.99.
Found: C 73.07%, H 5.94%, N 9.78%.
2878, 1744, 1682, 1593, 1491, 1443, 1416, 1368, 1320,
1236, 1194, 1131, 1103, 1068, 1025, 934, 906, 842, 772,
723, 695 cm21. MS .FAB1) m/e: 294 .[M11]1, 100), 293
.M1, 28), 154 .16), 137 .14), 136 .17), 123 .10), 119 .18),
109 .17), 107 .16), 105 .17). Anal. Calc. for C18H19N3O
.293.36): C 73.69%, H 6.53%, N 14.32. Found: C
73.91%, H 6.67%, N 14.03%.
4.4.3. 2-Anilino-1-benzyl-4-phenyl-4,5-dihydro-1H-5-imida-
zolone 010c). According to the general procedure described
above, the reaction between 7c and benzyl amine 8a
afforded after recrystallization from CCl4 0.59 g .88%) of
10c as a colourless solid. M.p.: 129±1308C. 1H NMR
.CDCl3): d 4.75 .d, 1H, Jˆ14.2Hz, PhC H2), 4.83 .s, 1H,
CH), 4.87 .d, 1H, Jˆ14.2Hz, PhC H02), 5.04 .s, br., 1H,
NH), 6.95±7.50 .m, 15Harom.). 13C NMR .CDCl3): d 42.80
.t, PhCH2), 61.16 .d, CH), 122.48 .d, 2CHarom.), 123.89 .d,
CHarom.), 126.49 .d, 2CHarom.), 127.65 .d, CHarom.), 128.42
.d, 2CHarom.), 128.69 .d, 2CHarom.), 128.81 .d, 2CHarom.),
128.96 .d, 2CHarom.), 129.54 .d, CHarom.), 135.60 .s,
Carom.), 136.31 .s, Carom.), 147.28 .s, C.2)), 149.01 .s,
Carom.), 171.63 .s, CO). IR .KBr) n 3388, 3057, 3036,
2917, 2868, 1750, 1670, 1591, 1491, 1451, 1435, 1412,
1361, 1335, 1307, 1278, 1264, 1229, 1187, 10632, 941,
899, 774, 728, 695 cm21. MS .FAB1) m/e: 342.[M 11]1,
19), 341 .M1, 74), 340 .11), 313 .14), 312.17), 209..10),
208 .13), 207 .49), 117 .11), 106 .100), 104 .13), 91 .52), 77
.37), 65 .18), 51 .12). Anal. Calc. for C22H19N3O .341.41):
C 77.40%, H 5.61%, N 12.31. Found: C 77.61%, H 5.76%,
N 12.03%.
4.4. Synthesis of 2-amino imidazolones derivatives of
type 10, 11, 15, 16 and 17. General procedure
To a solution of 2mmol .1 equiv.) of the corresponding
carbodiimides 7a±c in 6 mL of dry THF, 2.2 mmol
.1.1 equiv.) of the corresponding amines 8a±f were added
at r.t. The reaction mixture was stirred at r.t. under Ar for the
time speci®ed in Tables 2±4. After completion of the
reaction .TLC and/or GC monitoring), the solvent was
removed under reduced pressure and the resulting residue
was puri®ed by ¯ash-chromatography .n-hexane:AcOEt)
and dried under high vacuum.
4.4.1. 2-Anilino-1-benzyl-4-methyl-4,5-dihydro-1H-
5-imidazolone 010a). According to the general procedure
described above, the reaction between 7a and benzyl amine
8a afforded 0.48 g .86%) of 10a as a colourless oil. 1H NMR
.CDCl3): d 0.79 .d, 3H, Jˆ6.9 Hz, CH3), 4.02.q, 1H,
Jˆ6.9 Hz, CH), 4.86 .s, 2H, PhCH2), 4.94 .s, br., 1H,
NH), 7.0±7.55 .m, 10Harom.). 13C NMR .CDCl3): d 18.01
.q, CH3), 42.45 .t, PhCH2), 53.24 .d, CH), 122.29 .d,
2CHarom.), 123.09 .d, CHarom.), 127.55 .d, CHarom.), 128.38
.d, 2CHarom.), 128.57 .d, 2CHarom.), 129.34 .d, 2CHarom.),
136.41 .s, Carom.), 147.43 .s, C.2)), 149.08 .s, Carom.),
174.13 .s, CO). IR .®lm) n 3335, 3063, 3023, 2977, 2930,
1742, 1676, 1592, 1545, 1490, 1441, 1418, 1391, 1367,
1322, 1278, 1237, 1197, 1131, 110, 1075, 990, 835, 758,
744, 730, 697 cm21. MS .FAB1) m/e: 280 .[M11]1, 100),
279 .M1, 25), 207 .30), 165 .20), 149 .31), 147 .39), 145
.54), 119 .78), 109 .93), 105 .98). Anal. Calc. for
C17H17N3O .279.34): C 73.10%, H 6.13%, N 15.04.
Found: C 73.07%, H 5.96%, N 15.32%.
4.4.4. 2-Anilino-4-methyl-1-propyl-4,5-dihydro-1H-5-imi-
dazolone 010d). According to the general procedure
described above, the reaction between 7a and n-propyl
amine 8b afforded 0.35 g .76%) of 10d as a colourless oil.
1H NMR .CDCl3): d 0.97 .t, 3H, Jˆ7.4 Hz, CH3), 1.35 .d,
3H, Jˆ6.9 Hz, CH3), 1.74 .sext., 2H, Jˆ7.4 Hz, CH2), 3.62
.t, 2H, Jˆ7.2Hz, NC H2), 3.95 .q, 1H, Jˆ6.9 Hz, H4), 4.55
.s, br., 1H, NH), 6.95±7.35 .m, 5Harom.). 13C NMR .CDCl3):
d 11.12.q, CH3), 18.07 .q, CH3), 20.94 .t, CH2), 40.60
.t, NCH2), 53.06 .d, CH), 122.31 .d, 2CHarom.), 123.02
.d, CHarom.), 129.30 .d, 2CHarom.), 147.55 .s, C.2)), 149.57
.s, Carom.), 174.45 .s, CO). IR .KBr) n 3329, 3057, 3022,
2964, 2933, 2877, 1735, 1675, 1592, 1490, 1454, 1446,
1422, 1372, 1321, 1278, 1229, 1210, 1132, 1089, 1046,
1025, 835, 793, 751, 730, 698 cm21. MS .FAB1) m/e: 2 32
.[M11]1, 100), 231 .M1, 23), 230 .14), 161 .13), 145 .22),
123 .18), 121 .16), 119 .41), 109 .38), 107 .26), 105 .32).
Anal. Calc. for C13H17N3O .231.29): C 67.51%, H 7.41%, N
18.17. Found: C 67.67%, H 7.51%, N 17.93%.
4.4.2. 2-Anilino-1-benzyl-4-ethyl-4,5-dihydro-1H-5-
imidazolone 010b). According to the general procedure
described above, the reaction between 7b and benzyl
amine 8a afforded 0.49 g .84%) of 10b as a colourless oil.
1H NMR .CDCl3): d 0.79 .t, 3H, Jˆ7.4 Hz, CH3), 1.65±
1.70 .m, 2H, CH2), 3.85 .t, 1H, Jˆ5.7 Hz, CH), 4.69 .s, br.,
1H, NH), 4.76 .s, 2H, PhCH2), 6.90±7.45 .m, 10Harom.).
13C NMR .CDCl3): d 8.55 .q, CH3), 25.24 .t, CH3CH2),
42.49 .t, PhCH2), 58.36 .d, CH), 122.31 .d, 2CHarom.),
123.10 .d, CHarom.), 127.57 .d, CHarom.), 128.39
.d, 2CHarom.), 128.65 .d, 2CHarom.), 129.45 .d, 2CHarom.),
133.51 .s, Carom.), 147.66 .s, C.2)), 149.44 .s, Carom.),
173.39 .s, CO). IR .®lm) n 3343, 3063, 3029, 2967, 2926,
4.4.5. 2-Anilino-4-ethyl-1-propyl-4,5-dihydro-1H-5-imida-
zolone 010e). According to the general procedure described
above, the reaction between 7b and n-propyl amine 8b
1
afforded 0.38 g .75%) of 10e as a colourless oil. H NMR
.CDCl3): d 0.8 .t, 3H, Jˆ7.5 Hz, CH3), 0.89 .t, 3H,
Jˆ7.4 Hz, CH3), 1.60±1.75 .m, 4H, 2CH2), 3.56 .t, 2H,
Jˆ7.2Hz, NC H2), 3.85 .t, 1H, Jˆ5.6 Hz, CH), 4.60 .s, br.,
1H, NH), 6.85±7.30 .m, 5Harom.). 13C NMR .CDCl3): d 8.41
.q, CH3), 11.21 .q, CH3), 21.02 .t, CH2), 25.12 .t, CH2),
40.65 .t, NCH2), 58.18 .d, CH), 122.34 .d, 2CHarom.),
123.04 .d, CHarom.), 129.40 .d, 2CHarom.), 147.74 .s, C.2)),
149.98 .s, Carom.), 173.67 .s, CO). IR .KBr) n 3297, 3072,

4382
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
3051, 2972, 2952, 2932, 2873, 1713, 1681, 1588, 1488,
1452, 1415, 1374, 1321, 1213, 1125, 1101, 1063, 848,
772, 745, 696 cm21. MS .FAB1) m/e: 246 .[M11]1,
100), 245 .M1, 20), 207 .10), 159 .12), 147 .32), 145
.10). Anal. Calc. for C14H19N3O .245.32): C 68.54%,
H 7.81%, N 17.13%. Found: C 68.26%, H 7.94%, N 16.92%.
1287, 1222, 1180, 1135, 1068, 990, 927, 793, 765, 735,
706, 681 cm21. MS .FAB1) m/e: 260 .[M11]1, 100), 259
.M1, 11), 204 .51), 202 .24). Anal. Calc. for C15H21N3O
.259.35): C 69.47%, H 8.16%, N 16.20%. Found: C 69.25%,
H 8.01%, N 16.47%.
4.4.9. 2-0tert-Butylamino)-1,4-diphenyl-4,5-dihydro-1H-
5-imidazolone 011c). According to the general procedure
described above, the reaction between 7c and tert-butyla-
mine 8c afforded 0.44 g .72%) of 11c as a colourless solid.
4.4.6. 2-Anilino-4-phenyl-1-propyl-4,5-dihydro-1H-5-imi-
dazolone 010f). According to the general procedure
described above, the reaction between 7c and n-propyl
amine 8b afforded 0.52g .89%) of 10f as a colourless
1
M.p.: 119±1208Cdec. H NMR .CDCl3): d 1.32.s, 9H,
1
solid. M.p.: 135±1368Cdec. H NMR .DMSO-d6): d 0.86
3CH3), 3.72.s, br., 1H, N H), 5.12.s, 1H, C H), 7.05±7.40
.m, 10Harom.). 13C NMR .CDCl3): d 29.40 .q, 3CH3), 52.38
.s, Ct-bu), 69.95 .d, CH), 127.29 .d, 2CHarom.), 127.89
.d, 2CHarom.), 128.05 .d, CHarom.), 128.88 .d, 2CHarom.),
129.45 .d, CHarom.), 130.46 .d, 2CHarom.), 132.73 .s,
Carom.), 138.28 .s, Carom.), 152.94 .s, C.2)), 179.13 .s, CO).
IR .KBr) n 3382, 3058, 3029, 2980, 2961, 2924, 1739,
1636, 1596, 1513, 1496, 1451, 1393, 1355, 1295, 120,
1159, 1103, 1025, 927, 751, 704, 690 cm21. MS .FAB1)
m/e: 308 .[M11]1, 10), 307 .M1, 16), 252 .20), 251 .20),
222 .23), 159 .36), 132 .33), 131 .36), 119 .77), 118 .40), 85
.26), 83 .40), 81 .26), 77 .65), 73 .24), 71 .38), 69 .52), 67
.25), 60 .22), 57 .100), 56 .31), 55 .73), 51 .26). Anal. Calc.
for C19H21N3O .307.39): C 74.24%, H 6.89%, N 13.67%.
Found: C 74.14%, H 7.06%, N 13.54%. Spectroscopic data
for 12: 1H NMR .CDCl3): d 1.47 .s, 18H, 6CH3), 6.65 .s, br.,
2H, 2NH), 7.15±7.45 .m, 16Harom.), 7.55±7.65 .m, 2Harom.),
.t, 3H, Jˆ7.4 Hz, CH3), 1.65 .sext., 2H, Jˆ7.4 Hz, CH2),
3.5 .t, 2H, Jˆ6.9Hz, NCH2), 5.07 .d, 1H, Jˆ2Hz, C H),
6.90±7.40 .m, 10Harom.), 7.75 .d, 1H, Jˆ2Hz, N H). 13C
NMR .DMSO-d6): d 11.05 .q, CH3), 20.59 .t, CH2), 40.05
.t, NCH2), 60.51 .CH), 121.98 .d, CHarom.), 122.48
.d, CHarom.), 126.74 .d, CHarom.), 127.99 .d, CHarom.),
128.47 .d, CHarom.), 128.93 .d, CHarom.), 137.23 .s, Carom.),
147.99 .s, Carom.), 149.26 .s, C.2)), 172.15 .s, CO). IR .KBr)
n 3290, 3044, 3022, 2959, 2931, 2875, 1725, 1683, 1665,
1589, 1489, 1452, 1420, 1368, 1335, 1300, 1236, 1208,
1159, 1112, 1060, 1004, 899, 850, 779, 744, 698 cm21
.
MS .FAB1) m/e: 294 .[M11]1, 16), 293 .M1, 68), 264
.10), 252 .13), 251 .59), 250 .37), 236 .13), 222 .24), 207
.11), 183 .15), 182.100), 176 .58), 175 .38), 146 .11), 145
.13), 131 .14), 119 .21), 118 .44), 107 .10), 106 .92), 104
.32), 93 .10), 92 .10), 91 .38), 83 .12), 81 .11), 78 .13), 77
.74), 69 .23), 57 .22), 55 .20), 51 .25). Anal. Calc. for
C18H19N3O .293.36): C 73.69%, H 6.53%, N 14.32%.
Found: C 73.44%, H 6.71%, N 14.05%.
8.1±8.2.m, 2H arom.). M.p.: 149±1518Cdec
.
4.4.10. 2-Anilino-1-isopropyl-4-methyl-4,5-dihydro-1H-
5-imidazolone 010g) and 2-isopropyl-amino-4-methyl-1-
phenyl-4,5-dihydro-1H-5-imidazolone 011d). According
to the general procedure described above, the reaction
between 7a and isopropyl amine 8f afforded 0.31 g .67%)
of 10g as a colourless solid. M.p.: 90±918Cdec, and 0.07 g
.15%) of 11d as a colourless solid. M.p.: 118±1198C.
Spectroscopic data for 10g: 1H NMR .CDCl3): d 1.35
.d, 3H, Jˆ6.8 Hz, CH3), 1.51 .d, 3H, Jˆ7 Hz, CH3), 1.55
.d, 3H, Jˆ7 Hz, CH3), 3.91 .q, 1H, Jˆ6.8 Hz, CH), 4.58
.m, 1H, Jˆ7 Hz, NCH.CH3)2), 4.69 .s, br., 1H, NH), 7.0±
7.40 .m, 5Harom.). 13C NMR .CDCl3): d 18.14 .q, CH3),
19.22 .q, 2CH3), 44.17 .d, NCH.CH3)2), 57.70 .d, CH),
122.29 .d, 2CHarom.), 122.96 .d, CHarom.), 129.38
.d, 2CHarom.), 147.84 .s, C.2)), 149.32 .s, Carom.), 174.35
.s, CO). IR .KBr) n 3343, 3077, 2917, 2931, 2890, 1743,
1679, 1590, 1487, 1425, 1387, 1324, 1222, 1137,
1041 cm21. MS .FAB1) m/e: 232 .[M11]1, 100), 231
.M1, 25), 218 .5), 204 .5), 190 .9), 189 .6), 188 .5).
Anal. Calc. for C13H17N3O .231.29): C 67.51%, H 7.41%,
N 18.17%. Found: C 67.32%, H 7.25%, N 17.99%. Spectro-
4.4.7. 2-0tert-Butylamino)-4-methyl-1-phenyl-4,5-dihydro-
1H-5-imidazolone 011a). According to the general
procedure described above, the reaction between 7a and
tert-butylamine 8c afforded 0.33 g .68%) of 11a as a colour-
less solid. M.p.: 59±608C. 1H NMR .CDCl3): d 1.39 .s, 9H,
3CH3), 1.48 .d, 3H, Jˆ7.4 Hz, CH3), 3.72.s, br., 1H, N H),
4.22 .q, 1H, Jˆ7.4 Hz, CH), 7.20±7.50 .m, 5Harom.). 13C
NMR .CDCl3): d 18.25 .q, CH3), 28.73 .q, 3CH3), 51.57
.s, Ct-bu), 62.27 .d, CH), 127.27 .d, 2CHarom.), 128.83
.d, CHarom.), 129.91 .d, 2CHarom.), 132.23 .s, Carom.),
151.20 .s, C.2)), 181.52 .s, CO). IR .KBr) n 3424, 3063,
2959, 2927, 2869, 1734, 1652, 1595f, 1457, 1364, 1304,
1221, 1182, 1132, 763, 738, 695 cm21. MS .FAB1) m/e:
246 .[M11]1, 100), 245 .M1, 8), 192.19), 191.13), 190
.71), 189 .16), 188 .32), 136 .18), 133 .62). Anal. Calc. for
C14H19N3O .245.32): C 68.54%, H 7.81%, N 17.13%.
Found: C 68.25%, H 7.91%, N 16.97%.
4.4.8. 2-0tert-Butylamino)-4-ethyl-1-phenyl-4,5-dihydro-
1H-5-imidazolone 011b). According to the general proce-
dure described above, the reaction between 7b and tert-
butylamine 8c afforded 0.38 g .75%) of 11b as a colourless
1
scopic data for 11d: H NMR .CDCl3): d 1.12.d, 6H,
Jˆ6.4 Hz, 2CH3), 1.41 .d, 3H, Jˆ7.4 Hz, CH3), 3.62
.s, br., 1H, NH), 4.01 .m, 1H, Jˆ6.4 Hz, NCH.CH3)2),
4.11 .q, 1H, Jˆ7.4 Hz, CH), 7.15±7.50 .m, 5Harom.). 13C
NMR .CDCl3): d 17.17 .q, CH3), 22.68 .q, CH3), 22.85
.q, CH3), 43.41 .d, NCH.CH3)2), 62.00 .d, CH), 127.21
.d, 2CHarom.), 128.92 .d, CHarom.), 130.0 .d, 2CHarom.),
132.12 .s, Carom.), 152.73 .s, C.2)), 181.87 .s, CO). IR
.KBr) n 3344, 3069, 3043, 2966, 2926, 2864, 1724, 1646,
1593, 1520, 1453, 1370, 1344, 1322, 1279, 1239, 1159,
1126, 1068, 957, 844, 767, 735, 706, 690 cm21. MS
.FAB1) m/e: 232 .[M11]1, 89), 231 .M1, 6), 178 .18),
1
solid. M.p.: 73±748C. H NMR .CDCl3): d 1.01 .t, 3H,
Jˆ7.3 Hz, CH3), 1.42.s, 9H, 3C H3), 1.90±1.95 .m, 2H,
CH2), 3.73 .s, br., 1H, NH), 4.23 .t, 1H, Jˆ5.3 Hz, H4),
7.20±7.55 .m, 5Harom.). 13C NMR .CDCl3): d 8.51
.q, CH3), 25.47 .t, CH2), 29.06 .q, 3CH3), 51.62.s, Ct-bu),
67.20 .d, CH), 127.34 .d, 2CHarom.), 128.68 .d, CHarom.),
129.94 .d, 2CHarom.), 132.35 .s, Carom.), 151.55 .s, C.2)),
180.96 .s, CO). IR .KBr) n 3353, 2974, 2961, 2929, 2869,
1724, 1653, 1596, 1523, 1493, 1458, 1398, 1365, 1305,

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4383
165 .10), 154 .16), 149 .22), 145 .13), 137 .12), 136 .20),
133 .100), 131 .15), 123 .13), 121 .16), 119 .40), 115 .20),
109 .27), 107 .30), 105 .38). Anal. Calc. for C13H17N3O
.231.29): C 67.51%, H 7.41%, N 18.17%. Found: C
67.22%, H 7.66%, N 17.96%.
.14), 93 .11), 91 .26), 77 .55), 76 .15), 65 .12), 51 .20).
Anal. Calc. for C18H19N3O .293.36): C 73.69%, H 6.53%, N
14.32%. Found: C 73.51%, H 6.82%, N 14.15%.
4.4.13. 4-Methyl-1-phenyl-2-tetrahydro-1H-1-pyrrolyl-
4,5-dihydro-1H-5-imidazolone 015a). According to the
general procedure described above, the reaction between
7a and pyrrolidine 13a afforded 0.21 g .88%) of 15a as a
4.4.11. 2-Anilino-4-ethyl-1-isopropyl-4,5-dihydro-1H-5-
imidazolone 010h) and 4-ethyl-2-isopropylamino-1-
phenyl-4,5-dihydro-1H-5-imidazolone 011e). According
to the general procedure described above, the reaction
between 7b and isopropyl amine 8f afforded 0.17 g .35%)
of 10h as a colourless solid. M.p.: 91±928C, and 0.17 g
.35%) of 11e as a colourless solid. M.p.: 120±1218C. Spec-
1
colourless solid. M.p.: 63±648C. H NMR .CDCl3): d 1.39
.d, 3H, Jˆ7.4 Hz, CH3), 1.60±1.75 .m, 4H), 3.0±3.05 .m,
4H), 4.14 .q, 1H, Jˆ7.4 Hz, CH), 7.15±7.40 .m, 5Harom.).
13C NMR .CDCl3): d 18.30 .q, CH3), 25.15 .t, 2CH2), 48.46
.t, 2CH2), 61.71 .d, CH), 127.64 .d, 2CHarom.), 128.29 .d,
CHarom.), 129.33 .d, 2CHarom.), 134.90 .s, Carom.), 156.2.s,
C.2)), 182.80 .s, CO). IR .KBr) n 2966, 2929, 2872, 1740,
1616, 1490, 1418, 1329, 1251, 1176, 1130, 1078, 1027, 981,
885, 750, 699 cm21. MS .FAB1) m/e: 244 .[M11]1, 100),
243 .M1, 11), 320 .31), 205 .22), 189 .20), 137 .21), 136
.45), 107 .72), 105 .10). Anal. Calc. for C14H17N3O
.243.30): C 69.11%, H 7.04%, N 17.27%. Found: C
69.15%, H 6.85%, N 17.01%.
1
troscopic data for 10h: H NMR .CDCl3): d 0.92.t, 3H,
Jˆ7.4 Hz, CH3), 1.52.d, 3H, Jˆ6.9 Hz, CH3), 1.53 .d, 3H,
Jˆ6.9 Hz, CH3), 1.70±1.85 .m, 2H, CH2), 3.86 .t, 1H,
Jˆ5.2Hz, C H), 4.59 .m, 1H, Jˆ6.9 Hz, NCH.CH3)2),
4.66 .s, br., 1H, NH), 6.95±7.40 .m, 5Harom.). 13C NMR
.CDCl3): d 8.13 .q, CH3), 19.17 .q, CH3), 19.29 .q, CH3),
25.62 .t, CH2), 44.19 .d, NCH.CH3)2), 57.62.d, CH),
122.28 .d, 2CHarom.), 122.90 .d, CHarom.), 129.41
.d, 2CHarom.), 147.99 .s, C.2)), 149.71 .s, Carom.), 173.57
.s, CO). IR .KBr) n 3338, 2968, 2926, 2877, 2853, 1725,
1677, 1590, 1487, 1458, 1428, 1385, 1331, 1246, 1218,
1123, 1080, 934, 874, 720, 691 cm21. MS .FAB1) m/e:
246 .[M11]1, 100), 245 .M1, 32), 204 .22), 202 .20),
159 .18). Anal. Calc. for C14H19N3O .245.32): C 68.54%,
H 7.81%, N 17.13%. Found: C 68.41%, H 7.92%, N
4.4.14.
4-Ethyl-1-phenyl-2-tetrahydro-1H-1-pyrrolyl-
4,5-dihydro-1H-5-imidazolone 015b). According to the
general procedure described above, the reaction between
7b and pyrrolidine 13a afforded 0.25 g .98%) of 15b as a
1
colourless oil. H NMR .CDCl3): d 0.88 .t, 3H, Jˆ7.4 Hz,
CH3), 1.60±1.80 .m, 4H), 1.80±1.95 .m, 2H, CH2), 3.0±
3.05 .m, 4H), 4.13 .t, 1H, Jˆ5.5 Hz, CH), 7.15±7.40 .m,
5Harom.). 13C NMR .CDCl3): d 8.74 .q, CH3), 25.15 .t,
2CH2), 25.56 .t, CH2), 48.45 .t, 2CH2), 66.73 .d, CH),
127.62 .d, 2CHarom.), 128.25 .d, CHarom.), 129.33 .d,
2CHarom.), 134.97 .s, Carom), 156.18 .s, C.2)), 182.81 .s,
CO). IR .®lm) n 3064, 3043, 2966, 2931, 2868, 1743,
1616, 1496, 1454, 1419, 1342, 1335, 1229, 1180, 1145,
906, 758, 716, 681 cm21. MS .FAB1) m/e: 258 .[M11]1,
100), 257 .M1, 17), 205 .32), 189 .23), 136 .29), 107 .15).
Anal. Calc. for C15H19N3O .257.33): C 70.01%, H 7.44%, N
16.33%. Found: C 70.23%, H 7.25%, N 17.21%.
1
16.87%. Spectroscopic data for 11e: H NMR .CDCl3): d
0.90 .t, 3H, Jˆ7.3 Hz, CH3), 1.11 .d, 3H, Jˆ6.3 Hz, CH3),
1.12.d, 3H, Jˆ6.3 Hz, CH3), 1.80±2.0 .m, 2H, CH2), 3.62
.s, br., 1H, NH), 4.02.m, 1H, Jˆ6.3 Hz, NCH.CH3)2), 4.11
.t, 1H, Jˆ5.3 Hz, CH), 7.10±7.50 .m, 5Harom.). 13C NMR
.CDCl3): d 8.61 .q, CH3), 22.67 .q, CH3), 22.81 .q, CH3),
25.40 .t, CH2), 43.40 .d, NCH.CH3)2), 66.89 .d, CH),
127.21 .d, 2CHarom.), 128.89 .d, CHarom.), 129.96
.d, 2CHarom.), 132.11 .s, Carom.), 151.95 .s, C.2)), 181.17
.s, CO). IR .KBr) n 3336, 3050, 2965, 2920, 2875, 2853,
1728, 1640, 1595, 1524, 1497, 1454, 1371, 1341, 1328,
1293, 1264, 1215, 1155, 1130, 1104, 1068, 983, 765, 737,
716, 695 cm21. MS .FAB1) m/e: 246 .[M11]1, 100), 245
.M1, 5), 133 .19), 119 .25). Anal. Calc. for C14H19N3O
.245.32): C 68.54%, H 7.81%, N 17.13%. Found:
C 68.26%, H 7.94%, N 16.99%.
4.4.15. 4-Methyl-2-morpholine-1-phenyl-4,5-dihydro-
1H-5-imidazolone 015c). According to the general proce-
dure described above, the reaction between 7a and morpho-
line 13b afforded 0.20 g .80%) of 15c as a colourless solid.
M.p.: 95±978C. 1H NMR .CDCl3): d 1.49 .d, 3H, Jˆ7.4 Hz,
CH3), 3.06 .t, 4H, Jˆ4.8 Hz), 3.6 .t, 4H, Jˆ4.8), 4.18 .q,
1H, Jˆ7.4 Hz, CH), 7.30±7.50 .m, 5Harom.). 13C NMR
.CDCl3): d 17.74 .q, CH3), 47.44 .t, 2CH2), 62.08 .d,
CH), 65.87 .t, 2CH2), 125.81 .d, 2CHarom.), 128.04 .d,
CHarom.), 129.38 .d, 2CHarom.), 134.55 .s, Carom.), 158.38
.s, C.2)), 182.40 .s, CO). IR .KBr) n 3055, 2976, 2921,
2854, 1739, 1617, 1591, 1494, 1452, 1368, 1330, 1304,
1260, 1171, 1114f, 1008, 904, 868, 743, 698 cm21. MS
.FAB1) m/e: 260 .[M11]1, 100), 259 .M1, 14), 258 .42),
207 .16), 206 .83), 205 .11), 149 .25), 147 .18), 145 .47),
133 .49), 131 .29), 119 .47), 117 .25), 115 .17), 111 .22),
109 .45), 107 .33), 105 .46), 104 .19). Anal. Calc. for
C14H17N3O2 .259.30): C 64.85%, H 6.61%, N 16.21%.
Found: C 64.66%, H 6.48%, N 16.49%.
4.4.12. 2-Anilino-1-isopropyl-4-phenyl-4,5-dihydro-1H-
5-imidazolone 010i). According to the general procedure
described above, the reaction between 7c and isopropyl
amine 8f afforded 0.41 g .70%) of 10i as a yellow solid.
1
M.p.: 154±1558Cdec. H NMR .CDCl3): d 1.55 .d, 3H,
Jˆ7 Hz, CH3), 1.59 .d, 3H, Jˆ7 Hz, CH3), 4.66 .m, 1H,
Jˆ7Hz, NCH.CH3)2), 4.85 .s, 1H, CH), 5.07 .s, br. 1H,
NH), 7.05±7.45 .m, 10Harom.). 13C NMR .CDCl3): d 19.19
.q, CH3), 19.3 .q, CH3), 44.52.d, N CH.CH3)2), 60.67
.d, CH), 122.25 .d, 2CHarom.), 123.145 .d, CHarom.), 126.41
.d, 2CHarom.), 128.74 .d, CHarom.), 128.99 .d, 2CHarom.),
129.49 .d, 2CHarom.), 133.16 .s, Carom.), 147.72.s, C.2)),
149.3 .s, Carom.), 171.74 .s, CO). IR .KBr) n 3325, 3064,
3029, 2980, 2938, 2875, 1746, 1674, 1644, 1590, 1574,
1492, 1455, 1421, 1389, 1368, 1343, 1287, 1209, 1124,
1103, 1075, 983, 906, 842, 729, 699 cm21. MS .FAB1)
m/e: 294 .[M11]1, 100), 293 .M1, 63), 292 .40), 291
.43), 251.24), 250 .41), 248 .20), 182 .22), 176 .15), 172
4.4.16. 4-Ethyl-2-morpholine-1-phenyl-4,5-dihydro-1H-
5-imidazolone 015d). According to the general procedure
described above, the reaction between 7b and morpholine

4384
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
1
13b afforded 0.21 g .79%) of 15d as a colourless oil. H
NMR .CDCl3): d 0.92.t, 3H, Jˆ7.4 Hz, CH3), 1.70±2.05
.m, 2H, CH2), 2.90±3.15 .m, 4H), 3.05±3.55 .m, 4H), 4.12
.t, 1H, Jˆ5.5 Hz, CH), 7.20±7.45 .m, 5Harom.). 13C NMR
.CDCl3): d 8.79 .q, CH3), 25.16 .t, CH2), 47.49 .t, 2CH2),
65.89 .t, 2CH2), 67.09 .d, CH), 125.85 .d, 2CHarom.), 128.04
.d, CHarom.), 129.4 .d, 2CHarom.), 134.51 .s, Carom.), 158.74
.s, C.2)), 181.81 .s, CO). IR .®lm) n 3062, 3038, 2963,
2923, 2854, 1745, 1626, 1596, 1497, 1455, 1407, 1334,
1303, 1260, 1182, 1160, 1119f, 1070, 1014, 900, 881,
752, 730, 711, 693 cm21. MS .FAB1) m/e: 274 .[M11]1,
10), 273 .M1, 9), 207 .19), 206 .100), 205 .12), 189 .11),
149 .17), 133 .20), 109 .38). Anal. Calc. for C15H19N3O2
.273.33): C 65.91%, H 7.01%, N 15.37%. Found: C 66.12%,
H 6.85%, N 15.59%.
.t, 2CH2), 69.03 .d, CH), 125.91 .d, 2CHarom.), 126.81
.d, 2CHarom.), 127.91 .d, CHarom.), 128.18 .d, CHarom.),
128.60 .d, 2CHarom.), 129.45 .d, CHarom.), 134.48 .s, Carom.),
136.14 .s, Carom.), 159.27 .s, C.2)), 179.60 .s, CO). IR .KBr)
n 3060, 2990, 2972, 2913, 2888, 2852, 1743, 1619, 1591,
1492, 1450, 1393, 1365, 1328, 1300, 1256, 1221, 1160, 1115,
1068, 1020, 895, 795, 756, 703, 697 cm21. MS .FAB1) m/e:
322 .[M11]1, 100), 321 .M1, 19), 32 0 .35), 2 06 .2 8), 189
.20), 154 .30), 138 .11), 137 .21), 136 .29), 107 .10), 104
.10). Anal. Calc. for C20H20N2O2 .320.39): C 79.48%, H
6.29%, N 8.74%. Found: C 79.19%, H 6.07%, N 8.99%.
4.4.20. 4-05-Oxo-1,4-diphenyl-2-tetrahydro-1H-1-pyrro-
lyl-4,5-dihydro-1H-4-imidazolyl)-1,4-diphenyl-2-tetra-
hydro-1H-1-pyrrolyl-4,5-dihydro-1H-5-imidazolone
016). According to the general procedure described above,
the reaction between 7c and pyrrolidine 13a afforded after
crystallization of the residue with CH2Cl2:ether:n-pentane
instead of the chromatographic puri®cation, 0.23 g .75%) of
4.4.17. 2-Diethylamino-4-methyl-1-phenyl-4,5-dihydro-
1H-5-imidazolone 015e). According to the general proce-
dure described above, the reaction between 7a and diethyl
amine 13c afforded 0.22 g .92%) of 15e as a colourless oil.
1H NMR .CDCl3): d 1.03 .t, 6H, Jˆ7 Hz, 2CH3), 1.53
.d, 3H, Jˆ7.4 Hz, CH3), 3.09 .q, 4H, Jˆ7 Hz, 2NCH2),
4.27 .q, 1H, Jˆ7.4 Hz, CH), 7.30±7.55 .m, 5Harom.). 13C
NMR .CDCl3): d 12.34 .q, 2CH3), 18.2.q, CH3), 42.86
.t, 2NCH2), 61.88 .d, CH), 126.51 .d, 2CHarom.), 128.06
.d, CHarom.), 129.38 .d, 2CHarom.), 135.16 .s, Carom.),
157.92.s, C.2)), 183.56 .s, CO). IR .®lm) n 3063, 3036,
2973, 2931, 2871, 1742, 1621, 1537, 1495, 1450, 1415,
1378, 1333, 1277, 1179, 1115, 1076, 895, 781, 744,
698 cm21. MS .FAB1) m/e: 246 .[M11]1, 52), 231
.M1,22), 244 .64), 234 .10), 193.16), 192 .100), 175 .27),
119 .41). Anal. Calc. for C14H19N3O2 .245.32): C 68.54%,
H 7.81%, N 17.13%. Found: C 68.26%, H 7.97%, N
17.01%.
1
the dimer 16 as a colourless solid. M.p.: 171±1728C. H
NMR .DMSO-d6): d 1.85±1.80 .m, 8H), 3.15±3.30 .m,
8H), 6.55±7.35 .m, 20Harom.). 13C NMR .DMSO-d6): d
25.19 .t, 4CH2), 48.69 .t, 4CH2), 90.9 .s, 2C.4)), 126.47
.d, 4CHarom.), 128.11 .d, 2CHarom.), 128.17 .d, 4CHarom.),
128.57 .d, 4CHarom.), 128.88 .d, 2CHarom.), 129.80 .d,
4CHarom.), 135.54 .s, 2Carom.), 141.74 .s, 2Carom.), 155.98
.s, 2C.2)), 180.75 .s, 2CO). IR .KBr) n 3056, 2971, 2868,
2824, 1766, 1609, 1578, 1488, 1450, 1434, 1350, 1311,
1225, 1193, 1169, 1126, 1065, 977, 909, 783, 753, 715,
692cm 21. MS .FAB1) m/e: 608 .M1, 10), 304 .5), 191
.29), 190 .100), 189 .13), 105 .18). Anal. Calc. for
C38H36N6O2 .608.73): C 74.98%, H 5.96%, N 13.81%.
Found: C 74.42%, H 6.17%, N 13.52%.
4.4.21. 2-Diethylamino-4-02-diethylamino-1,4-diphenyl-
5-oxo-4,5-dihydro-1H-4-imidazolyl)-1,4-diphenyl-4,5-
dihydro-1H-5-imidazolone 017). According to the general
procedure described above, the reaction between 7c and
diethylamine 13c afforded after crystallization of the residue
with CH2Cl2:ether:n-pentane instead of the chromatograph-
ic puri®cation, 0.24 g .77%) of the dimer 17 as a colourless
4.4.18. 2-Diethylamino-4-ethyl-1-phenyl-4,5-dihydro-1H-
5-imidazolone 015f). According to the general procedure
described above, the reaction between 7b and diethyl
amine 13c afforded 0.25 g .96%) of 15f as a colourless
1
oil. H NMR .CDCl3): d 0.80±0.95 .m, 9H, 3CH3), 1.80±
1.95 .m, 2H, CH2), 2.85±3.10 .m, 4H, 2NCH2), 4.13 .t, 1H,
Jˆ5.4 Hz, CH), 7.15±7.45 .m, 5Harom.). 13C NMR .CDCl3):
d 8.56 .q, CH3), 12.32 .q, 2CH3), 25.22 .t, CH2), 42.80
.t, 2NCH2), 66.95 .d, CH), 126.38 .d, 2CHarom.), 127.87
.d, CHarom.), 129.26 .d, 2CHarom.), 135.14 .s, Carom.),
158.27 .s, C.2)), 182.55 .s, CO). IR .®lm) n 3057, 3043,
2968, 2931, 2875, 1741, 1621, 1596, 1497, 1461, 1412,
1378, 1334, 1274, 1178, 1131, 1089, 1068, 1028, 984,
883, 782, 747, 694 cm21. MS .FAB1) m/e: 260 .[M11]1,
20), 259 .M1, 2), 193 .17), 192 .100), 183 .14), 119 .11),
100 .17). Anal. Calc. for C15H21N3O .259.35): C 69.47%,
H 8.16%, N 16.20%. Found: C 69.60%, H 7.95%, N
16.38%.
1
solid. M.p.: 159±1608C. H NMR .DMSO-d6): d 1.08 .t,
12H, Jˆ7.0 Hz, 4CH3), 2.85±3.10 .q, 8H, Jˆ7.0 Hz,
4NCH2), 6.70±7.70 .m, 20Harom.). 13C NMR .DMSO-d6):
d 12.32 .q, 4CH3), 42.80 .t, 4NCH2), 90.36 .s, 2C.4)),
126.38 .d, 4CHarom.), 127.87 .d, 2CHarom.), 129.26 .d,
4CHarom.), 135.14 .s, 2Carom.), 158.27 .s, 2C.2)), 182.55 .s,
2CO). IR .KBr) n 3059, 2987, 2967, 2930, 2790, 1757,
1612f, 1578, 1493, 1444, 1424, 1330, 1278, 1231, 1185,
1111, 1062, 1000, 877, 786, 753, 706, 695 cm21. MS
.FAB1) m/e: 613 .[M11]110), 612.M 1, 5), 193 .19),
192.100), 154 .17), 137 .13), 136 .19), 119 .11), 105
.17). Anal. Calc. for C38H40N6O2 .612.76): C 74.48%, H
6.58%, N 13.71%. Found: C 74.18%, H 6.36%, N 13.97%.
4.4.19. 2-Morpholino-1,4-diphenyl-4,5-dihydro-1H-5-imi-
dazolone 015h). According to the general procedure
described above, the reaction between 7c and morpholine
13b afforded after crystallization of the residue with
CH2Cl2:ether:n-pentane instead of the chromatographic puri-
®cation, 0.25 g .79%) of 15h as a colourless solid. M.p.:
138±1398C. 1H NMR .CDCl3): d 3.05±3.10 .m, 4H),
3.55±3.60 .m, 4H), 5.19 .s, 1H, CH), 7.20±7.40
.m, 10Harom.). 13C NMR .CDCl3): d 47.54 .t, 2CH2), 65.89
4.5. Synthesis of 4,5-dihydro-1H-5-imidazolones of
general structure 20. General procedure
Method A: To a solution of the corresponding carbodi-
imides 7a±b .1 mmol, 1 equiv.) in 3 mL of anhydrous
MeCN, 1 mmol .1 equiv.) of the corresponding amidines
18a±d .as hydrohalide salts; XˆBr for 18a, XˆI for 18b
and XˆCl for 18c and 18d) followed by 1 mmol K2CO3

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4385
were added sequentially at r.t. The reaction mixture was
stirred at r.t. under an Ar atmosphere for the time speci®ed
in Table 5. After completion of the reaction .TLC
monitoring) the solvent was eliminated under reduced
pressure and the resulting residue was partitioned with
25 mL of a 4:1 mixture of AcOEt:H2O. The organic layer
was separated and washed with 5 mL portions of brine .3£).
The organic layer was dried over anhydrous MgSO4, the
solvent eliminated under reduced pressure and the resulting
residue puri®ed by ¯ash-chromatography .n-hexane:
AcOEt) and the pure products dried under high vacuum.
4.5.3. 2-Imino0phenyl)methylamino-1-phenyl-4-methyl-
4,5-dihydro-1H-5-imidazolone 020c). According to the
general procedure described above .Method A), the reaction
between 7a and 18c afforded 0.13 g .48%) of 20c as a
1
colourless solid. M.p.: 132±1338C. H NMR .DMSO-d6):
d 1.52.d, 3H, Jˆ8.0 Hz, CH3), 4.51 .q, 1H, Jˆ8.0 Hz, CH),
7.40±7.90 .m, 10Harom.), 9.29 .s, br., 1H, NH), 10.58 .s, br.,
1H, NH). 13C NMR .DMSO-d6): d 17.59 .q, CH3), 61.87
.d, CH), 127.14 .d, CHarom.), 127.35 .d, 2CHarom.), 127.62
.d, 2CHarom.), 128.41 .d, 2CHarom.), 128.57 .d, 2CHarom.),
131.82.d, CHarom.), 135.49 .d, Carom.), 136.31 .d, Carom.),
161.05 .s, C.2)), 164.96 .s, C.2)), 178.72 .s, CO). IR
.KBr) n 3341, 3058, 2980, 1718, 1644, 1592, 1560, 1522,
Method B: To a solution of the carbodiimide 7c .1 mmol,
1 equiv.) in 3 mL of anhydrous MeCN, 1 mmol .1 equiv.) of
amidines 18b and 18d were added followed by the addition
of 1 mmol of DIPEA. After stirring at r.t. under Ar
atmosphere for the time speci®ed in Table 5, a solid preci-
pitates, which was ®ltered and washed sequentially with
MeCN, ether and n-pentane and dried under high vacuum.
1482, 1444, 1391, 1325, 1285, 1179, 1157, 766, 692 cm21
.
MS .FAB1) m/e: 293 .[M11]1, 100), 292 .M1, 10), 291
.21), 190 .34), 154 .16), 149 .22), 146 .19), 145 .31), 136
.24), 133 .22), 131 .24), 123 .27), 120 .20), 119 .49), 111
.24), 109 .49), 107 .38), 105 .49), 104 .38). Anal. Calc. for
C17H16N4O .292.13): C 69.85%, H 5.52%, N 19.17%.
Found: C 70.12%, H 5.33%, N 18.90%.
4.5.1. 2-Benzylsulfanyl0imino)methylamino-1-phenyl-4-
methyl-4,5-dihydro-1H-5-imidazolone 020a). According
to the general procedure described above .Method A), the
reaction between 7a and 18a afforded 0.23 g .69%) of 20a
4.5.4. 2-01-Iminoethylamino)-1-phenyl-4-methyl-4,5-
dihydro-1H-5-imidazolone 020d). According to the
general procedure described above .Method A), the reaction
between 7a and 18d afforded 0.13 g .55%) of 20d as a
1
as a colourless solid. M.p.: 143±1448C. H NMR .DMSO-
1
d6): d 1.18 .d, 3H, Jˆ7.4 Hz, CH3), 4.08 .s, 2H, CH2S), 4.27
.q, 1H, Jˆ7.4 Hz, CH), 6.80±7.45 .m, 10Harom.), 9.01 .s, br.,
1H, NH), 9.85 .s, br., 1H, NH). 13C NMR .CDCl3): d 17.59
.q, CH3), 34.82.t, CH2S), 62.31 .d, CH), 127.10 .d,
CHarom.), 127.44 .d, 2CHarom.), 127.61 .d, CHarom.), 128.32
.d, 2CHarom.), 128.52 .d, 2CHarom.), 128.62 .d, 2CHarom.),
133.69 .s, Carom.), 137.24 .s, Carom.), 159.34 .s, C.2)),
168.04 .s, CyN), 181.31 .s, CO). IR .KBr) n 3330, 3135,
3022, 2980, 2924, 2860, 1718, 1609, 1581, 1454, 1386,
1317, 1281, 1241, 1180, 1111, 1061, 962, 821, 751,
700 cm21. MS .FAB1) m/e: 340 .[M12]1, 2), 339
.[M11]1, 4), 243 .19), 215 .96), 190 .8), 92 .9), 91
.100). Anal. Calc. for C18H18N4OS .338.43): C 63.88%, H
5.36%, N 16.56%. Found: C 63.61%, H 5.13%, N 16.30%.
colourless solid. M.p.: 151±1528C. H NMR .DMSO-d6):
d 1.36 .d, 3H, Jˆ7.4 Hz, CH3), 1.93 .s, 3H, CH3), 4.25
.q, 1H, Jˆ7.4 Hz, CH), 7.25±7.50 .m, 5Harom.), 8.70
.s, br., 1H, NH), 9.92.s, br., 1H, NH). 13C NMR .DMSO-
d6): d 18.72.q, CH3), 24.92 .q, CH3), 61.58 .d, CH), 127.04
.d, CHarom.), 128.37 .d, 2CHarom.), 129.23 .d, 2CHarom.),
138.21 .s, Carom.), 160.70 .s, C.2)), 167.40 .s, CyN),
181.03 .s, CO). IR .KBr) n 3273, 3106, 3061, 2984, 2931,
2864, 1747, 1706, 1676, 1646, 1554, 1516, 1491, 1422,
1309, 1225, 1186, 1141, 1099, 1053, 1018, 760,
694 cm21. MS .FAB1) m/e: 231 .[M11]1, 100), 230
.M1, 13), 229 .17), 190 .38), 149 .29), 145 .33), 136
.25), 133 .23), 123 .25), 121.25), 119 .54), 117 .20), 111
.28), 109 .49), 107 .39), 105 .49). Anal. Calc. for
C12H14N4O .230.27): C 62.59%, H 6.13%, N 24.33%.
Found: C 62.33%, H 6.34%, N 24.17%.
4.5.2. 2-Decylsulfanyl0imino)methylamino-1-phenyl-4-
methyl-4,5-dihydro-1H-5-imidazolone 020b). According
to the general procedure described above .Method A), the
reaction between 7a and 18b afforded 0.25 g .65%) of 20b
as a colourless solid. M.p.: 68±698C. 1H NMR .DMSO-d6):
d 0.96 .t, 3H, Jˆ6.2Hz, C H3), 1.15±1.40 .m, 16H, 8CH2),
1.45 .d, 3H, Jˆ7.4 Hz, CH3), 2.7 .t, 2H, Jˆ7.2Hz, SC H2),
4.36 .q, 1H, Jˆ7.4 Hz, CH), 7.35±7.60 .m, 5Harom.), 9.05
.s, br., 1H, NH), 9.89 .s, br., 1H, NH). 13C NMR .DMSO-
d6): d 13.97 .q, CH3), 17.47 .q, CH3), 22.13 .t, CH2), 28.10
.t, CH2), 28.55 .t, CH2), 28.71 .t, CH2), 28.94 .t, 3CH2),
29.79 .t, CH2), 33.32.t, S CH2), 61.69 .d, CH), 127.11
.d, CHarom.), 127.53 .d, 2CHarom.), 128.24 .d, 2CHarom.),
134.01 .s, Carom.), 158.93 .s, C.2)), 168.22 .s, CyN),
180.68 .s, CO). IR .KBr) n 3359, 3219, 3156, 3064, 2959,
2919, 2850, 1707, 1617, 1587, 1510, 1488, 1454, 1385,
1319, 1278, 1236, 1186, 1114, 1060, 1011, 955, 892, 828,
751, 710, 690 cm21. MS .FAB1) m/e: 390 .[M12]1, 25),
389 .[M11]1, 100), 388 .M1, 10), 215 .69), 187 .21), 161
.20), 145 .32), 144 .28), 133 .53), 120.24), 119 .76), 117
.26), 115 .22), 114 .21), 109 .46), 107 .39), 105 .56). Anal.
Calc. for C21H32N4OS .388.57): C 64.91%, H 8.30%,
N 14.42%. Found: C 64.67%, H 8.46%, N 14.20%.
4.5.5. 2-Benzylsulfanyl0imino)methylamino-4-ethyl-1-
phenyl-4,5-dihydro-1H-5-imidazolone 020e). According
to the general procedure described above .Method A),
the reaction between 7b and 18a afforded 0.26 g .75%)
1
of 20e as a colourless solid. M.p.: 144±1458C. H NMR
.DMSO-d6): d 0.93 .t, 3H, Jˆ7.4 Hz, CH3), 1.60±1.95
.m, 2H, CH2), 3.96 .s, 2H, SCH2), 4.22 .dd, 1H,
Jˆ6.8 Hz, J0ˆ5.0 Hz, CH), 6.80±7.45 .m, 10Harom.),
9.02.s, br., 1H, N H), 9.90 .s, br., 1H, NH). 13C NMR
.CDCl3): d 9.6 .q, CH3), 25.34 .t, CH2), 34.87 .t, SCH2),
67.51 .d, CH), 127.13 .d, CHarom.), 127.46 .d, 2CHarom.),
127.64 .d, CHarom.), 128.34 .d, 2CHarom.), 128.55 .d,
2CHarom.), 128.65 .d, 2CHarom.), 133.68 .s, Carom.), 137.22
.s, Carom.), 159.65 .s, C.2)), 168.12 .s, CyN), 180.50 .s,
CO). IR .KBr) n 3347, 3301, 3032, 2966, 2925, 2871,
1711, 1604, 1584, 1515, 1387, 1318, 1186, 1124 cm21
.
MS .FAB1) m/e: 354 .[M12]1, 7), 353 .[M11]1, 32),
352.M 1, 2), 257 .22), 230 .17), 229 .100), 204 .12),
91 .93). Anal. Calc. for C19H20N4OS .352.45): C 64.74%,
H 5.72%, N 15.90%. Found: C 64.58%, H 5.93%, N
15.67%.

4386
M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4.5.6. 2-Decylsulfanyl0imino)methylamino-4-ethyl-1-
phenyl-4,5-dihydro-1H-5-imidazolone 020f). According
to the general procedure described above .Method A), the
reaction between 7b and 18b afforded 0.31 g .78%) of 20f
as a colourless solid. M.p.: 73±748C. 1H NMR .DMSO-d6):
d 0.95±1.40 .m, 22H, 2CH3, 8CH2), 1.70±2.00 .m, 2H,
CH2), 2.75 .t, 2H, Jˆ7.2Hz, SC H2), 4.32.dd, 1H,
Jˆ6.8 Hz, J0ˆ5 Hz, CH), 7.35±7.55 .m, 5Harom.), 9.05 .s,
br., 1H, NH), 9.96 .s, br., 1H, NH). 13C NMR .DMSO): d
9.37 .q, CH3), 13.97 .q, CH3), 22.13 .t, CH2), 24.82 .t, CH2),
28.10 .t, CH2), 28.54 .t, CH2), 28.72 .t, CH2), 28.94
.t, 2CH2), 29.79 .t, 2CH2), 31.32.t, CH2S), 66.82.d, CH),
127.11 .d, CHarom.), 127.47 .t, 2CHarom.), 128.27
.t, 2CHarom.), 133.97 .s, Carom.), 159.32.s, C.2)), 168.29
.s, CyN), 179.89 .s, CO). IR .KBr) n 3296, 3142, 2959,
2924, 2853, 1714, 1613, 1585, 1515, 1454, 1387, 1346,
1322, 1306, 1288, 1191, 1138, 1117, 1068, 1025, 990,
969, 835, 779, 751, 709, 695 cm21 MS .FAB1) m/e: 404
.[M12]1, 25), 403 .[M11]1, 100), 402.M 1, 5), 229 .58),
204 .37), 201 .25), 161 .21), 145 .27), 144 .32), 133 .56),
131 .30), 129 .26), 128 .23), 121 .26), 120 .26), 119 .86),
117 .32), 115 .27), 109 .56), 107 .47), 105 .66). Anal. Calc.
for C22H34N4OS .402.60): C 65.63%, H 8.51%, N 13.92%.
Found: C 65.82%, H 8.39%, N 13.65%.
C 63.91%, H 6.60%, N 22.93%. Found: C 64.17%, H
6.47%, N 23.14%.
4.5.9. 2-Decylsulfanyl0imino)methylamino-1,4-diphenyl-
4,5-dihydro-1H-5-imidazolone 020i). According to the
general procedure described above .Method B), the reaction
between 7c and 18b afforded 0.17 g .35%) of 20i as a
1
colourless solid. M.p.: 113±1148Cdec. H NMR .DMSO-
d6): d 0.90±1.60 .m, 19H, CH3, 8CH2), 2.6 .t, 2H,
Jˆ8 Hz, SCH2), 6.01 .s, 1H, CH), 6.70±8.15 .m, 10Harom.),
9.21 .s, br., 1H, NH), 10.43 .s, br., 1H, NH). 13C NMR
.DMSO-d6): d 13.9 .q, CH3), 22.061 .t, CH2), 27.98
.t, CH2), 28.50 .t, CH2), 28.63 .t, CH2), 28.88 .t, 2CH2),
29.75 .t, 2CH2), 31.32.t, CH2S), 76.71 .d, CH), 126.73
.d, CHarom.), 127.20 .d, 2CHarom.), 127.81 .d, 2CHarom.),
128.075 .d, 2CHarom.), 128.26 .d, 2CHarom.), 128.99
.d, CHarom.), 133.30 .s, Carom.), 134.34 .s, Carom.), 159.2.s,
C.2)), 169.25 .s, CyN), 176.59 .s, CO). IR .KBr) n 3323,
3219, 3125, 3063, 2960, 2919, 2851, 1716, 1600, 1566,
1498, 1436, 1375, 1299, 1215, 1180, 1103, 1068, 1032,
835, 800, 744, 716, 695 cm21. MS .FAB1) m/e: 452
.[M12]1, 17), 451 .[M11]1, 58), 450 .M1, 38), 449
.78), 277 .17), 161 .27), 154 .33), 145 .16), 144 .53), 137
.21), 136 .43), 120 .18), 119 .100), 118 .19), 105 .33), 104
.41), 103 .21). Anal. Calc. for C26H34N4OS .450.64):
C 69.30%, H 7.60%, N 12.43%. Found: C 69.00%,
H 7.82%, N 12.73%.
4.5.7. 2-Imino0phenyl)methylamino-4-ethyl-1-phenyl-
4,5-dihydro-1H-5-imidazolone 020g). According to the
general procedure described above .Method A), the reaction
between 7b and 18c afforded 0.16 g .56%) of 20g as a
4.5.10. 2-01-Iminoethylamino)-1,4-diphenyl-4,5-dihydro-
1H-5-imidazolone 020j). According to the general proce-
dure described above .Method B), the reaction between 7c
and 18d afforded 61 mg .20%) of 20j as a colourless solid.
1
colourless solid. M.p.: 139±1408C. H NMR .DMSO-d6):
d 1.08 .t, 3H, Jˆ7.4 Hz, CH3), 1.80±2.10 .m, 2H, CH2),
4.42.dd, 1H, Jˆ6.0 Hz, J0ˆ4.0 Hz, CH), 7.50±7.95
.m, 10Harom.), 9.29 .s, br., 1H, NH), 10.62.s, br., 1H,
NH). 13C NMR .DMSO-d6): d 9.8 .q, CH3), 25.27
.t,CH2), 67.30 .d, CH), 127.14 .d, CHarom.), 127.33
.d, 2CHarom.), 127.42 .d, 2CHarom.), 128.38 .d, 2CHarom.),
128.41 .d, 2CHarom.), 131.72.d, CHarom.), 134.09 .s, Carom.),
134.33 .s, Carom.), 161.64 .s, C.2)), 163.46 .s, CyN), 179.92
.s, CO). IR .KBr) n 3342, 3142, 3050, 2952, 2931, 2875,
1705, 1633, 15993, 1572, 1524, 1497, 1447, 1385, 1345,
1319, 1308, 1190, 1155, 1053, 1025, 997, 842, 772, 730,
695 cm21. MS .FAB1) m/e: 307 .[M11]1, 100), 306 .M1,
12). Anal. Calc. for C18H18N4O .306.36): C 70.57%, H
5.92%, N 18.29%. Found: C 70.80%, H 5.77%, N 18.01%.
1
M.p.: 165±1668Cdec. H NMR .DMSO-d6): d 2.04 .s, 3H,
Jˆ7.4 Hz, CH3), 5.85 .s, 1H, CH), 6.85±7.85 .m, 10Harom.),
9.32.s, br., 1H, N H), 10.71 .s, br., 1H, NH). 13C NMR
.DMSO-d6): d 23.51 .q, CH3), 76.68 .d, CH), 126.77 .d,
CHarom.), 127.25 .d, 2CHarom.), 127.40 .d, 2CHarom.), 127.86
.d, CHarom.), 128.29 .d, 2CHarom.), 128.41 .d, 2CHarom.),
133.61 .s, Carom.), 134.65 .s, Carom.), 160.98 .s, C.2)),
168.43 .s, CyN), 177.02.s, CO). IR .KBr) n 3360, 3090,
1714, 1623, 1588, 1513, 1380, 1300, 1183, 995, 872, 747,
729, 693 cm21. MS .FAB1) m/e: 293 .[M11]1, 12), 292
.M1, 25), 172 .100). Anal. Calc. for C17H16N4O .292.34):
C 69.85%, H 5.52%, N 19.17%. Found: C 70.13%, H 5.23%,
N 18.88%.
4.5.8. 2-01-Iminoethylamino)-4-ethyl-1-phenyl-4,5-di-
hydro-1H-5-imidazolone 020h). According to the general
procedure described above .Method A), the reaction
between 7b and 18c afforded 0.17 g .65%) of 20h as a
4.6. X-ray crystallographic details. General procedure36
Rigaku AFC5R diffractometer, graphite-monochromated
Ê
1
colourless solid. M.p.: 160±1618C. H NMR .DMSO-d6):
d 0.94 .t, 3H, Jˆ7.4 Hz, CH3), 1.60±1.90 .m, 2H, CH2),
MoKa radiation, lˆ0.71073 A, unit cell dimensions from
25 centred re¯ections, v ±2u scans, intensities of 3
standards checked after every 150 re¯ections: no decay.
The intensities were corrected for Lorentz and polarization
effects, but not for absorption. Structure solution by direct
methods using SHELXS-8637 and re®ned on F with weights
of wˆ[s2.Fo)1.0.005Fo)2]21 by full-matrix least-squares
methods using TEXSAN.38
1.94 .s, 3H, CH3), 4.21 .t, 1H, Jˆ6.4 Hz, CH), 7.20±7.45
.m, 5Harom.), 8.69 .s, br., 1H, NH), 9.95 .s, br., 1H, NH). 13
C
NMR .DMSO-d6): d 9.56 .q, CH3), 24.37 .q, CH3), 25.42
.t, CH2), 67.65 .d, CH), 127.11 .d, 2CHarom.), 127.21 .d,
CHarom.), 128.49 .d, 2CHarom.), 133.73 .s, Carom.), 161.69
.s, C.2)), 166.92 .s, CyN), 181.04 .s, CO). IR .KBr) n
3369, 3140, 3064, 2963, 2931, 2876, 1709, 1629, 1578,
1532, 1503, 1456, 1422, 1382, 1322, 1279, 1255, 1190,
1125, 1101, 1074, 1029, 996, 746, 728, 695 cm21. MS
.FAB1) m/e: 245 .[M11]1, 23), 244 .M1, 4), 233 .26),
205 .22), 204 .11), 195 .22), 194 .19), 186 .16), 159
.100), 132.5)2. Anal. Calc. for C 13H16N4O .244.29):
4.6.1. Crystallographic data for compound 10g0 0Fig. 4).
C13H17N3O, Mrˆ231.30, orthorhombic, space group
Ê
P212121, aˆ11.165.2), bˆ11.255.3), cˆ10.054.2) A,
Vˆ1263.4.4) A , Zˆ4, Dcˆ1.216 Mg m23, F.000)ˆ496,
Ê 3
Tˆ190.1) K, m.MoKa)ˆ0.0796 mm21, colourless prism,

M. Heras et al. / Tetrahedron 57 52001) 4371±4388
4387
dimensions: 0.22£0.25£0.45 mm, 2u range 58±558, 2048
measured re¯ections of which 1673 were unique
.Rintˆ0.029). The methyl substituent on the ®ve-membered
ring is disordered so that it lies both above and below the
plane of the ®ve-membered ring. Two positions were
de®ned for this group with equal site occupation factors.
Although the compound crystallizes in a chiral space
group, this disorder indicates that the compound is racemic.
All non-H atoms re®ned anisotropically, amine H-atom
re®ned isotropically, all other H-atoms ®xed in calculated
positions. The re®nement of 168 parameters using 1099
observed re¯ections with I.2s.I) gave Rˆ0.0459,
through project UdG98-452, Medichem S.A. .Barcelona)
Â
and Roviall Quõmica S.L. .Murcia) is gratefully acknow-
ledged. Thanks are also due to Dr LluÈisa Matas .Servei
Â
d'Analisi, Universitat de Girona) for recording the NMR
spectra and performing the microanalyses and to Dr M.
Â
Maestro and Dr J. Mahõa .Servicios Xerais de Apoio a
Investigacion, Universidade da CorunÄa) for recording
Â
Â
mass spectra.
References
wRˆ0.0340, Sˆ1.682, max. and min. Drˆ0.17;
1. Ishikawa, F.; Kosasayama, A.; Nakamura, S.; Konno, T.
Chem. Pharm. Bull 1978, 26, 3658.
Ê 23
20.16 e A
.
2. Ishikawa, F.; Kosasayama, A.; Konno, T. Chem. Pharm. Bull.
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4.6.2. Crystallographic data for compound 11e 0Fig. 5).
C14H19N3O, Mrˆ245.32, monoclinic, space group Cc,
3. Kosasayama, A.; Watanabe, Y.; Higashi, K.; Ishikawa, F.
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aˆ14.925.2), bˆ9.416.2), cˆ11.701.2) A, bˆ124.977.6)8,
Ê 3
Vˆ1347.4.4) A , Zˆ4, Dcˆ1.209 Mg m23, F.000)ˆ528,
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Pharm. Bull. 1979, 27, 841.
Tˆ173.1) K, m.MoKa)ˆ0.0784 mm21, colourless prism,
dimensions: 0.33£0.33£0.50 mm, 2u range 58± 608, 2147
measured re¯ections of which 2030 were unique
.Rintˆ0.022). All non-H atoms re®ned anisotropically,
H-atoms re®ned isotropically. The re®nement of 238 para-
meters using 1799 observed re¯ections with I.2s.I) gave
5. Gadwood, R. C.; Kamdar, B. V.; Dubray, L. A. C.; Wolfe,
M. L.; Smith, M. P.; Watt, W.; Mizsak, S. A.; Groppi, V. E.
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Rˆ0.0358, wRˆ0.0316, Sˆ1.734, max. and min. Drˆ0.23;
Ê 23
20.19 e A
.
8. Pettit, G. R.; Herald, C. L.; Leet, J. E.; Gupta, R.;
Schaufelberger, D. E.; Bates, R. B.; Clewlow, P. J.; Doubek,
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4.6.3. Crystallographic data for compound 12 0Fig. 3).
C38H40N6O2´2CH2Cl2, Mrˆ782.64, triclinic, space group
Ê
P1, aˆ10.379.3), bˆ12.050.3), cˆ8.836.2) A, aˆ
Ê 3
107.71.2), bˆ89.97.3), gˆ69.86.2)8, Vˆ981.5.5) A ,
9. Chan, G. W.; Mong, S.; Hemling, M. E.; Freyer, A. J.; Offen,
P. H.; DeBrosse, C. W.; Sarau, H. M.; Westley, J. W. J. Nat.
Prod. 1993, 56, 116±121.
Zˆ1, Dcˆ1.324 Mg m23
,
colourless prism, dimensions:
F.000)ˆ410, Tˆ173.1) K,
m.MoKa)ˆ0.344 mm21
,
0.30£0.33£0.40 mm, 2u range 58±558, 4758 measured
re¯ections of which 4511 were unique .Rintˆ0.016). The
asymmetric unit contains one half of the molecule of 12,
which sits across a centre of inversion, plus one molecule of
CH2Cl2. All non-H atoms re®ned anisotropically, H-atoms
re®ned isotropically. The re®nement of 323 parameters
using 3303 observed re¯ections with I.2s.I) gave
10. Tsukamoto, S.; Kato, H.; Hirota, H.; Fusetani, N. J. Nat. Prod.
1996, 59, 501±503.
11. Olofson, A.; Yakushijin, K.; Horne, D. A. J. Org. Chem. 1998,
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14. Molina, P.; Almendros, P.; Fresneda, P. M. Tetrahedron Lett.
1994, 35, 2235.
Rˆ0.0465, wRˆ0.0417, Sˆ2.395, max. and min.
Ê 23
Drˆ0.42; 20.30 e A
.
15. Villalgordo, J. M.; Obrecht, D.; Chucholowski, A. Synlett
1998, 1405±1407.
4.6.4. Crystallographic data for compound 20e0 0Fig. 8).
C19H20N4OS, Mrˆ352.45, monoclinic, space group P21/n,
16. Chucholowsky, A.; Masquelin, T.; Obrecht, D.; Stadlwieser,
J.; Villalgordo, J. M. Chimia 1996, 50, 525.
Ê
aˆ13.221.2), bˆ10.043.3), cˆ13.999.2) A, bˆ103.36.1)8,
Ê 3
Vˆ1808.6.6) A , Zˆ4, Dcˆ1.294 Mg m23, F.000)ˆ744,
17. Obrecht, D.; Abrecht, C.; Grieder, A.; Villalgordo, J. M. Helv.
Chim. Acta 1997, 80, 65.
Tˆ173.1) K, m.MoKa)ˆ0.193 mm21, colourless plate,
dimensions: 0.12£0.32£0.42mm, 2 u range 58±558, 4575
measured re¯ections of which 4151 were unique
.Rintˆ0.029). All non-H atoms re®ned anisotropically,
H-atoms ®xed in calculated positions. The re®nement of
226 parameters using 2590 observed re¯ections with
18. Heras, M.; Ventura, M.; Linden, A.; Villalgordo, J. M.
Synthesis 1999, 1613.
19. Markwalder, J. A.; Pottorf, R. S.; Seitz, S. P. Synlett 1997, 521.
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1992, 48, 6385.
I.2s.I) gave Rˆ0.0620, wRˆ0.0583, Sˆ2.373, max. and
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