Synthesis of 3-Ω-aminohydantoins

Article abstract of DOI:10.1002/jhet.5570390521

Several 3-Ω-amino monosubstituted hydantoins have been obtained in the reaction of isocyanate of glycine ethyl ester with the appropriate aliphatic or aromatic diamine. It was found, that the 3-(aminoaryl) monosubstituted hydantoins may be diazotized and their diazonium salts may be coupled and hydrolysed without changes in the hydantoin ring.

Full text of DOI:10.1002/jhet.5570390521

Sep-Oct 2002
997
Synthesis of 3-W-Aminohydantoins
Józef Ryczek
·
Department of Chemistry, Pedagogical University , Podchor¸azych 2 St., 30-084 Kraków, Poland
Received November 27, 2001
Several 3-W-amino monosubstituted hydantoins have been obtained in the reaction of isocyanate of
glycine ethyl ester with the appropriate aliphatic or aromatic diamine. It was found, that the 3-(aminoaryl)
monosubstituted hydantoins may be diazotized and their diazonium salts may be coupled and hydrolysed
without changes in the hydantoin ring.
J. Heterocyclic Chem., 39, 997(2002).
Derivatives of hydantoin have different pharmacological
activity [1] and technical applications [2]. It was found that
differently substituted hydantoins with amino and dialky-
lamino groups are active against central nervous system
[3,4] and cardiovascular system [5] disorders. There have
been few 3-monosubstituted dialkylaminoalkyl hydantoins
obtained till now and their synthesis offers rather limited
possibilities [6]. 3-Monosubstituted hydantoins with the
free amine group with the substituent at the 3 position are
even more scarce and their syntheses have low yield [7] or
is protected by patents [8,9].
0 °C. Chloroform or anhydrous ethanol was used as sol-
vents due to the solubility of the substrates. After the reac-
tion, the unisolated intermediate, i.e., a derivative of ethyl
ester of hydantoic acid, was cyclised under acidic (HCl)
conditions to the appropriate hydantoin in water-ethanol
solution. The raw product obtained was purified as a
hydrochloride or, after transformation, as a free base. For
the synthesis of derivatives with a free amino group a
monoacetyl derivative of the diamine was used as sub-
strate. It was found that when a monoalkyldiamine, i.e.
N-methyl-1,3-propanediamine, was used the reaction did
not follow the proposed scheme (Scheme 1). Immediately
after mixing of reagents a mixture of various products was
Results and Discussion.
In this paper 3-monosubstituted amino and dialkylamino
alkyl and aryl hydantoins were synthesized according to
the known method [10] and its applications [11]. It
involves the reaction between the appropriate diamine and
the isocyanate of glycine ethyl ester (Scheme 1). The reac-
tion was carried out at room temperature or alternatively at
obtained, evidenced by monitoring the reaction in CDCl
3
1
solution by H NMR spectroscopy. After careful evapora-
tion of the solvent and drying under reduced pressure at 40
°C the intermediate was hydrolysed in HCl medium. A
mixture of different products was obtained and among
them ca. 10% of N-methyl-1,3-propanediamine hydro-
1
chloride, the presence of which (confirmed by H NMR,
Scheme 1
13
C NMR and MS) may mean that during the mentioned
reaction a partial amidation of the ester group of the iso-
cyanate occured. To obtain the indole derivative of
3-monosubstituted hydantoin, 5-aminoindole and iso-
cyanate of glycine ethyl ester were used (Scheme 1). The
indole derivative of the ester of hydantoic acid 9 was
obtained with satisfactory yield but attempts to cyclise it to
the hydantoin derivative proved unsuccessful although
HCl, CH COOH and heating without a solvent were tried.
3
In each case the final result was a mixture of different,
unidentified substances.
One of the major aims of this work was to determine
whether the free amine group in the 3-monoaminoaryl sub-
stituent reacts without simultaneous changes in the hydan-
toin ring. The reactions were carried out with 3-(4'-
aminophenyl)hydantoin 8, which was transformed in the
non-isolated diazonium salt (8a) (Scheme 2) at 0 °C with-
out a change of the NH group of the hydantoin ring in the
nitroso group [12]. This salt was remarkably stable and
could be heated at 80 °C for several hours without decom-
position but after 5 hours heating at 100 °C it was hydrol-
ysed with 45% yield to 3-(4'-hydroxyphenyl)hydantoin 10
(Scheme 3), identical with the specimen obtained by
another method [11]. The diazonium salt was also coupled
Compounds 1-3, 5, 6 and 8 are hydrochlorides

998
J. Ryczek
Vol. 39
Table 1
Preparative, Physical and Analytical Data for the Compounds 1-12
Compound Yield Mp/°C Recrystn. Found /Calcd. m/z
.
+
(Formula)
(%)
solvent
C
H
N
M
1
99.5 238-9
EtOH
40.4 6.8 20.2 171
40.1 6.8 19.9
C H N O •HCl
7
13 3 2
2
99.7 157-8
99.7 206-7
EtOH
EtOH
45.9 7.7 17.8 199
45.8 7.7 17.8
43.3 7.3 18.9 185
43.1 7.1 18.6
C H N O •HCl
3 [6]
C H N O •HCl
with b-naphthol in alkaline medium (Scheme 3) yielding
an azo dye 11 with indicator properties.
9
17 3 2
8
15 3 2
The strong alkaline medium of the reaction did not cause
opening of the hydantoin ring, which is usual at this pH.
This allowed the Japp-Klingeman reaction with ethyl
2-methylacetoacetate to occur, leading to phenylhydrazone
derivative 12 (Scheme 3). This was treated with HCl in
anhydrous ethanol and BF in CH COOH. In the first case
4
52.4 119-20 Cyclohexane 51.9 8.2 22.7 185
51.8 8.2 22.6
C H N O
5
C H N O •HCl
6
C
6a
C
7
8
15 3 2
99.5 205-7
93.4 220-21
59.9 220-21
53.3 188-9
99.8 238-9
99.3 173-4
45.3 291-2
86.2 266-7
35.2 286-7
EtOH
33.4 5.6 23.4 143
33.4 5.6 23.2
51.7 5.5 16.4 219
51.4 5.5 16.1
5
9 3 2
EtOH
H N O •HCl
11 13 3 2
EtOH
+benzene
EtOH
+benzene
EtOH
3
3
H N O
the substance remained unchanged, whereas treatment
11 13 3 2-
63.1 6.9 17.0 247
63.0 6.9 16.7
47.5 4.4 18.4 191
47.4 4.4 18.3
59.8 5,8 16.1 261
59.5 5.6 15.8
56.2 4.2 14.6 192
56.0 4.1 14.6
65.9 4,1 16.2 346
65.6 3.9 15.9
55.2 5.3 18.4 304
55.0 5.3 18.1
with BF resulted in a mixture of different products.
3
C
8
H
N O
3 2
13 17
C H N O •HCl
9
C
10 [11]
C H N O
11
C
9
9 3 2
EtOH
EtOH
AcOH
AcOH
H N O
13 15 3 3
9
8
2
2
H N O
19 14 4 3
12
C
H N O
14 16 4 4
of diastereotopic hydrogen atoms were theoretically calculated
using a computer program (written by Dr. E Szneler from the
NMR Laboratory of the Jagiellonian University). For compound
10 the coupling between aromatic protons was interpreted from
1
1
the H , H COSY spectra and chemical shifts of carbon atoms
were ascribed from HETCOR and HMBC spectra. The interpre-
tation of 1H and 13C NMR spectra was supported by the program
gNMR V3.6. Mass spectra were obtained on a Varian MAT-112
spectrometer at 70 eV. The reagents were from Aldrich (Poznan,
Poland).
The physicochemical data of compounds 1-12 are pre-
1
13
General Procedure.
sented in Table 1. Table 2 reports spectral (IR, H and
C
NMR) data, which unambiguously confirmed the structure
of the compounds obtained. A comparison of C NMR
spectra of hydrochloride 6 and free amine 6a revealed
broad signals for some carbon atoms of the phenyl moiety
To a solution of diamine (1.00 g) in 25 cm3 of chloroform or
monoacetyldiamine in 25 cm3 of anhydrous ethanol an equimolar
amount of isocyanate of glycine ethyl ester in 25 cm3 of chloro-
form (for 1-4, 6 and 7) or 25 cm3 of anhydrous ethanol was added
dropwise with constant stirring. The mixture was stirred for 2
hours and the solvent was evaporated on a rotary evaporator
under reduced pressure and thoroughly dried at 40 °C under
reduced pressure. The residue was dissolved in 25 cm3 of ethanol
and 25 cm3 of 5 M HCl was added. The mixture was refluxed for
3 hours then the solvent was evaporated and the raw product was
crystallized from the appropriate solvent (Table 1).
13
and N(CH ) group in this first compound but not in the
3 2
second, whereas a significant shift of d values of these
C
atoms was observed in this last compound. This phenome-
non may be associated with the lack of inversion of config-
uration at the nitrogen atom in hydrochloride 6.
EXPERIMENTAL
Free Base for Hydantoins with a Phenylamine Group (6a and 7).
The of hydrochloride of compound 6 (0.5 g, 1.95 mmol) was
dissolved in 5 cm3 of water and conc. ammonia solution was
added dropwise to alkaline reaction. The separated precipitate
was isolated by filtration and washed with water until neutral.
The precipitate was dried and crystallized from the mixture of
ethanol and benzene. Yield 0.257 g (59.9%) of 6a.
Mps were uncorrected and measured on a Boetius apparatus.
CHN analyses were acquired on a Perkin Elmer 2400 analyzer.
IR spectra were recorded on a Zeiss Specord 75 IR apparatus in
1
KBr discs. H and 13C NMR spectra were obtained on a Bruker
500 apparatus in DMSO d6 and CDCl3 with TMS as an internal
standard. Spin-spin coupling constants are given in Hz and those

Sep-Oct 2002
999
Synthesis of 3-W-Aminohydantoins
Table 2
1
13
IR and HNMR and CNMR Spectroscopic Data for the Compounds 1-12
-1
Compound
n
(KBr) cm
d [500 MHz DMSO d ; TMS]
d [125 MHz DMSO d ; TMS]
C 6
max
H
6
1
3295 (NH)
2.75 (s, 6H, N(CH ) ), 3.24 (t, 2H, J=5.5 Hz,
36.79 (C(6)H ), 45.49- (N(CH ) ),
2 3 2
3 2
1785, 1720 (CO)
C(6)H ), 3.68 (t, 2H, J=5.5Hz, C(7)H ), 3.88
46.83 (C(5)H ), 57.16 (C(7)H ), 158.68 (C(2)O),
2
2
2
2
(s, 2H, C(5)H ), 8,22 (br s, 1H, N(1)H)
172.45 (C(4)O)
2
2
3325 (NH)
1.19 (t, 6H, J=7.1Hz, N(CH -CH ) ), 3.13 (m, 4H,
8.04 (N(CH -CH ) ), 32.35 (C(6)H ), 45.81
3 2 2 2
3
2 2
1730, 1695 (CO)
N(CH -CH ) ), 3.18 (m, 2H C(6)H ), 3.69 (t, 2H, J=6.4 Hz,
(N(CH -CH ) ), 47.23 (C(5)H ), 47.55 (C(7)H ),
3
2 2
2
3 2 2 2 2
C(7)H ), 3.88 (s, 2H, C(5)H ), 8,22 (br s, H, N(1)H)
157.75 (C(2)O), 172.30 (C(4)O)
22.96 (C(7)H ), 34.85 (C(6)H ), 41.93
2
2
3 [6]
3120 (NH)
1.88 (m, 2H, C(7)H ), 2.67 (s, 6H, N(CH ) ), 3.00 (2H,
2 3 2
2
2
1730, 1655 (CO)
t, 2H, J=8.00 Hz, C(6)H ), 3.37 (2H, m, 2H, C(8)H ),
(N(CH ) ), 45.95 (C(5)H ), 54.05 (C(8)H ),
2
2
3 2 2 2
3.88 (s, 2H, C(5)H ), 8.15 (1H, br s, 1H, N(1)H)
157.42 (C(2)O), 172.17 (C(4)O)
16.13 (C(6)H ), 45.22 (C(7)H), 45.55
2
4
3045 (NH)
1.36 (d, 3H , J= 7.0 Hz, C(7)H ), 2.18 (q, 1H, J=4.8 Hz,
3
3
x
x
y
1745, 1690 (CO)
(C(8)H , C(6)H), J=12.5 Hz, ((C(8)H , C(8)H ),
(C(8)H H )), 2.22 (s, 6H, N(CH ) ), 3.15 (q, 1H,
J=10.7 Hz, (C(8)H , C(6)H), J= 12.5 Hz, ((C(8)H ,
C(8)H ), (C(8)H H )), 4.29*(m, 1H, J=7.0 Hz, (C(7)H ,
C(6)H), J=4.8 Hz, (C(8)H , C(6)H), J=10.7 Hz, (C(8)H ,
C(6)H), 3.91(s, 2H, C(5)H ), 6.53(br s, 1H, N(1)H)
(N(CH ) ), 46.13 (C(5)H ), 61.20 (C(8)H ),
3 2 2 2
x
y
158.70 (C(2)O), 171. 77 (C(4)O)
3 2
y
x
y
x y
3
y
x
2
5
3200, 3140 (NH ,
2.49(t, 2H, J= 6.0 Hz, C(7)H ), 3.59 (t, 2H J= 6.0 Hz,
35.43 (C(7)H ), 36.93 (C(6)H ), 46.16 (C(5)H ),
2 2 2
2
2
NH)
C(6)H ), 3.85(s, 2H C(5)H ), 8.18(d, 2H, N(1)H, NH )
157.32 (C(2)O), 172.40 (C(4)O)
2
2
2
1745, 1660 (CO)
3250 (NH)
6
3.08(s, 6H, N(CH ) ), 4.05(s, 2H, C(5)H ), 7.46(d, 2H,
3 2 2
br.43.61 (N(CH ) , 46.02 (C(5)H ), br.118.03
3 2
2
1760, 1700 (CO)
J= 8.5 Hz, C(8,10)H), 7.72(d, 2H, J= 8.5, Hz, C(7, 11)H),
8.42(br s, 1H, N(1)H)
(C(8,10)H), 127.79 (C(7,11)H) and C(6),
br.144.98 C(9), 156.38 (C(2)O), 171.06 (C(4)O)
40.46 (N(CH ) ), 46.46 (C(5)H ), 112.54
6a
7
3220 (NH)
2.98(s, 6H, N(CH ) ), 4.05(s, 2H, C(5)H ), 6.65(br s, 1H,
3 2 2
3 2
2
1750, 1745 (CO)
N(1)H), 6.76(d, 2H, J= 9.0 Hz, C(8,10)H), 7.18(d,
2H, J= 9.0 Hz, C(7, 11)H),
(C(8,10)H), 119.59 C(6), 127.17 (C(7,11)H),
150.46 C(9), 158.38 (C(2)O), 170.77 (C(4)O)
3305 (NH)
1.08(t, 6H, J= 7.0 Hz, N(CH -CH ) ), 3.33(q, 4H,
12.34 (N(CH -CH ) ), 43.75 (N(CH -CH ) ),
3
2 2
3 2 2 3 2 2
1755, 1690 (NH)
J= 7.0 Hz, N(CH -CH ) ), 4.00(s, 2H C(5)H ),
45.87 (C(5)H ), 111.00 (C(8,10)H, 119.50 C(6),
3
2 2
2
2
6.66(d, 2H, J= 8.7 Hz, C(8,10)H), 7.02 (2H, d, 2H,
J= 8.7 Hz, C(7, 11)H), 8.14(1H, br s, 1H, N(1)H)
127,89 (C(7,11)H), 146.78 C(9), 157.19 (C(2)O),
171.48 (C(4)O)
8
9
3420, 3340, 3280
4.04(s, 2H, C(5)H ), 7.35(m, 4H, J= 8.6 Hz,
C(7,8,10,11)H), 8.36(s, 1H, N(1)H), 10.30(br s,
45.99 (C(5)H ), 122.10 (C(8,10)H), 127.97
(C(7,11)H), 129.99 C(6), 133.72 C(9), 156.27
(C(2)O), 170.99 (C(4)O)
2
2
(NH , NH)
2
1770, 1690 (CO)
3260 (NH)
2H, NH )
2
1.21(t, 3H, J= 7.1 Hz, C(16)H ), 3.86(d, 2H, J= 5.9 Hz,
14.14 (C(16)H ), 41.46 (C(13)H ), 60.29
3
3 2
1730 (CO),
C(13)H ), 4.11(q, 2H, J= 7.1 Hz, C(15)H ), 6.31(m,
(C(15)H ), 100.78, 109.36, 109.67, 111.16,
2
2
2
1575 (CO ester)
2H, C(2,3)H), 7.02(d, 1H, C(7)H), 7,26(m, 2H, C(4,6)H),
7.61(br s, 1H,N (12)H), 8.48(br s, 1H, N(10)H),
10.99(br s, 1H, N(1)H)
114.48, 126.31, 127.70, 132.00, (C(2)H, C(3)H,
C(4)H, C(5), C(6)H, C(7)H, C(8), C(9)),
155.73 (C(14)O), 171.11 (C(11)O)
10 [11]
3420 (OH), 3240
(NH)
1760, 1673 (CO)
3220 (OH), 3100
(NH)
4.02(s, 2H, C(5)H ), 6.82(d, 2H, J= 8.8 Hz, C(8,10)H),
7.09(d, 2H, J= 8.8 Hz, C(7,11)H), 8.17(br s, 1H,
45.89 (C(5)H ), 115.21 (C(8,10)H), 123.30 C(6),
128.13 (C(7,11)H), 156.85, 156.89 C(9) and
(C(2)O), 171.28 (C(4)O)
2
2
**)
N(1)H), 9.65(s, 1H, OH(9)
11
4.11(s, 2H, C(5)H ), 6.92(d, 1H, J= 9.0 Hz, C(16)H),
46.07 (C(5)H ), 119.03 (C(8)H and C(10)H),
2
2
7.47(m, 1H, J= 7.0 Hz and J= 8.0 Hz C(19)H),
7.55(d, 2H, J= 8.5 Hz, C(7,11)H), 7.62(m, 1H,
J= 7.0 Hz and J= 8.0 Hz C(20)H), 7.79(d, 1H,
J= 8.0 Hz, C(18)H), 7.96(d,2H, J= 9.0 Hz,
C(8,10)H), 7.96(d, 1H, J= 9.0 Hz, C(17)H),
8.56(d, 1H, J= 8.0 Hz, C(21)H), 8.42(br s, 1H N(1)H)
121,45 (C(21)H), 124.01 (C(16)H), 126.01
(C(19)H), 127,73 (C(7)H and C(11)H), 127.90
(C(20)H), 128.96 (C(18)H), 129.39 C(15), 140.27
(C(17)H), 129.16, 132.71 (C(14), C(22) and
C(23)), 131.53, 143.93 (C(9) and C(6)), 156.31
(C(2)O), 171.06 (C(4)O)
1750, 1700 (CO)
12
3295, 3100 (NH)
1750, 1700 (CO),
1560 (CO ester)
1.27(t, 3H, J= 7.0 Hz, C(18)H ), 2.08(s, 3H,
11.82 (C(18)H ), 14.18 (C(14)H ), 45.87
(C(5)H ), 60.22 (C(17)H ), 113.50 (C(8,10)H),
2 2
125.03 C(9), 127.55 (C(7,11)H), 132.60 C(6),
143.74 C(15), 156.72 (C(2)O), 164.76
(C(16)O), 171.15 (C(4)O)
3
3 3
C(14)H ), 4.04(s, 2H, C(5)H ), 4.20(q, 2H, J= 7.0 Hz,
3
2
C(17)H ), 7.22(d, 2H, J= 8.7 Hz, C(8,10)H), 7.32(d,
2
2H, J= 8.7 Hz, C(7,11)H), 8.25(br s, 1H, N(1)H),
9.97(br s, 1H, N(12)H)
Compounds 4 and 6a were measured in CDCl ; * J values for this multiplet were calculated; ** after addition of D O the signal at 9,65 ppm disappeared.
3
2
Free base for Hydantoin with a Dialkylaminoalkyl Group (4).
evaporated and the residue was dried. The precipitate was boiled
twice with 20 cm3 of benzene and filtered. The combined filtrates
were evaporated and the residue was crystallized from cyclo-
hexane. Yield 0.82 g (98.2%) of 4.
The hydrochloride of compound 4 (1.0 g, 4.7 mmol) was dis-
solved in 25 cm3 of ethanol and an equimolar amount of piperi-
dine (0.4 g) in 25 cm3 of ethanol was added. The solvent was

1000
J. Ryczek
Vol. 39
4-[3'-(2',4'-Imidazolidinedione)]benzenediazonium Chloride
(8a).
added dropwise with stirring. The solution was added to the dia-
zonium salt prepared from 2.00 g of amine 8 (above). Then 20
cm3 of water was added and the mixture stirred for 1 hour. The
separated precipitate was isolated by filtration, washed with
water till neutral, dried and crystallized from glacial acetic acid
yielding 0.94 g (35.2%) of 12.
To a solution of 2.00 g (8.7 mmol) of 3-(4'-aminophenyl)-
hydantoin hydrochloride 8 in 50 cm3 of water, 1.7 cm3 of conc.
HCl was added and the mixture was chilled to 0 °C. Then 0.605 g
(8.8 mmol) of NaNO2 in 1.7 cm3 of water was added dropwise
during 45 minutes under constant stirring and keeping the tem-
perature at 0 °C. The stirring was continued for 15 minutes after
addition of the nitrite.
Acknowledgements.
Thanks are due to Dr. E. Szneler from the NMR Laboratory of
Jagiellonian University for calculations of NMR data for
compound 4.
3-(4'-Hydroxyphenyl)-2,4-imidazolidinedione (10).
To the obtained diazonium salt (above) 30 cm3 of water was
added and heated under reflux for 5 hours at 100 °C. The reaction
course was monitored by the coupling reaction with b-naphthol
until no red azo dye formation was observed. After completion of
reaction the solution was evaporated under reduced pressure and
the residue was dried. The precipitate was boiled twice with 25
cm3 of acetone and filtered. Acetone was evaporated from the
combined filtrates and the residue was crystallized from ethanol
yielding 0.765 g (45.3%) of 10.
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2-Hydroxynaphthelene-1-azo[4-(3-imidazolidine-2,4-dione)]-
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To the diazonium salt obtained from 2.00 g of compound 8
(above) chilled to 0 °C a solution of equimolar amount of
b-naphthol (1.266 g) in 6.3 cm3 of 10% NaOH was added with
stirring. A precipitate was formed immediately. Then 50 cm3 of
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mixture was filtered and washed with water till neutral. The pre-
cipiate was dried and crystallized from glacial acetic acid yield-
ing 2.625 g (86.2%) of 11.
2-[4'-(3"-(2",4"-Imidazolidinedione))phenylhydrazone]ethyl
Propionate (12)
Ethyl 2-methylacetoacetate (1.27 g, 8.8 mmol) was dissolved
in 9.4 cm3 of anhydrous ethanol and chilled to –5 °C. At that tem-
perature slowly a cold solution of 3.11 cm3 of 50% KOH was
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