Geminal systems 50. Synthesis and alcoholysis of N-acyloxy-N-alkoxy derivatives of ureas, carbamates, and benzamides

Article abstract of DOI:10.1023/B:RUCB.0000011887.40529.b0

Procedures were developed for the synthesis of N-acyloxy-N-alkoxy derivatives of ureas, carbamates, and benzamides by the reactions of the corresponding N-alkoxy-N-chloro derivatives with sodium carboxylates in MeCN. N-Chloro-N-ethoxy-p-toluenesulfonamide was inert in this reaction. Alcoholysis of N-acyloxy-N-alkoxy derivatives of ureas, carbamates, and tert-alkylamines afforded the corresponding N,N-dialkoxy derivatives, whereas alcoholysis of N-acetoxy-N-ethoxybenzamide gave rise to alkyl benzoates.

Full text of DOI:10.1023/B:RUCB.0000011887.40529.b0

Russian Chemical Bulletin, International Edition, Vol. 52, No. 10, pp. 2251—2260, October, 2003
2251
Geminal systems
50.* Synthesis and alcoholysis of NꢀacyloxyꢀNꢀalkoxy derivatives
of ureas, carbamates, and benzamides
V. G. Shtamburg,a E. A. Klots,a A. P. Pleshkova,b V. I. Avramenkoa,
a
a
c
ꢀ
S. P. Ivonin, A. V. Tsygankov, and R. G. Kostyanovsky
aDnepropetrovsk National University,
134 ul. Nauchnaya, 49050 Dnepropetrovsk, Ukraine.
Fax: +38 (056) 24 6314. Eꢀmail: heterosycle@ff.dsu.dp.ua
bA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5085
cN. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences,
4 ul. Kosygina, 119991 Moscow, Russian Federation.
Fax: +7 (095) 938 2156. Eꢀmail: kost@chph.ras.ru
Procedures were developed for the synthesis of NꢀacyloxyꢀNꢀalkoxy derivatives of ureas,
carbamates, and benzamides by the reactions of the corresponding NꢀalkoxyꢀNꢀchloro derivaꢀ
tives with sodium carboxylates in MeCN. NꢀChloroꢀNꢀethoxyꢀpꢀtoluenesulfonamide was inꢀ
ert in this reaction. Alcoholysis of NꢀacyloxyꢀNꢀalkoxy derivatives of ureas, carbamates, and
tertꢀalkylamines afforded the corresponding N,Nꢀdialkoxy derivatives, whereas alcoholysis of
NꢀacetoxyꢀNꢀethoxybenzamide gave rise to alkyl benzoates.
Key words: NꢀalkoxyꢀNꢀchloro derivatives of ureas, carbamates, benzamide, and pꢀtolueneꢀ
sulfonamide, sodium carboxylates, NꢀacyloxyꢀNꢀalkoxy derivatives of ureas, carbamates, and
1
tertiary alkylamines, alcoholysis, H NMR spectra, mass spectra, N,Nꢀdialkoxyamino derivaꢀ
tives of ureas and carbamates.
NꢀAlkoxyꢀN´,N´ꢀdialkylꢀNꢀchloroureas, N,Nꢀdialkꢀ
oxyꢀNꢀchloroamines, and NꢀalkoxyꢀNꢀchloroꢀtertꢀalkylꢀ
amines, which are representatives of the O—N—Cl gemiꢀ
nal system,2a are characterized by high anion mobility of
Cl atoms and serve as precursors of important classes of
compounds, such as dialkoxyamines2b,c and trialkoxyꢀ
amines.2b,d However, these compounds are rather unꢀ
stable.2
In this connection, we studied the synthesis of Nꢀacylꢀ
oxyꢀNꢀalkoxy derivatives of ureas and carbamates as well
as their transformations under conditions of alcoholysis.*
Earlier, the only NꢀacyloxyꢀNꢀalkoxyamine 1 has been
prepared (Scheme 1)5.
Scheme 1
A comparison of their properties with those of the
related N—C—X geminal system reveals the following
features. In chloromethylamines, the C—Cl bond is comꢀ
pletely ionized and these compounds exist as iminium
salts R2N+=CH2Cl–, whereas the corresponding acetoxyꢀ
methylamines exist in the covalent form AcOCH2NR2 as
stable distillable compounds.3 Hence, one would expect,
on the one hand, an increase in stability of NꢀacyloxyꢀNꢀ
alkoxy derivatives of ureas, amines, and carbamates comꢀ
pared to Nꢀchloro analogs and, on the other hand, the
anion mobility of the Nꢀacyloxy group, which provides an
easy access to N,Nꢀdialkoxy derivatives.
R = MeO(O)CC(Me)2—
We found that NꢀalkoxyꢀNꢀchloroureas also reacted
with sodium and potassium carboxylates in MeCN to
form NꢀacyloxyꢀNꢀalkoxyureas (Scheme 2).
NꢀAlkoxyꢀNꢀchloroureas 10—15, except for comꢀ
pound 9,6 have not been described earlier. We syntheꢀ
* For Part 49, see Ref. 1.
* For preliminary communications, see Ref. 4.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2132—2140, October, 2003.
1066ꢀ5285/03/5210ꢀ2251 $25.00 © 2003 Plenum Publishing Corporation

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Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
Shtamburg et al.
Scheme 2
3—4 months. Compounds 31, 32, and 36 are distillable in
vacuo (with partial decomposition).
The reactions of NꢀalkoxyꢀNꢀchlorobenzamides with
AcONa in MeCN proved to be a convenient way of preꢀ
paring NꢀacetoxyꢀNꢀalkoxybenzamides described earꢀ
lier,8—11 as exemplified by the synthesis of NꢀacetoxyꢀNꢀ
ethoxybenzamide (38) (Scheme 4).
Scheme 4
It is known that NꢀalkoxyꢀNꢀchlorosulfonamides reꢀ
main intact under the action of MeONa/MeOH.6 We
demonstrated that NꢀchloroꢀNꢀethoxytolueneꢀpꢀsulfonꢀ
amide (39) also did not react with AcONa in MeCN.
Therefore, it can be stated that the chlorine atom in
NꢀalkoxyꢀNꢀchlorosulfonamides possesses no anion moꢀ
bility.
The anion mobility of the acyloxy group in the resultꢀ
ing NꢀacyloxyꢀNꢀalkoxy derivatives of ureas and carbamꢀ
ates as well as in NꢀacyloxyꢀNꢀalkoxyamines was conꢀ
firmed by the formation of the corresponding N,Nꢀdiꢀ
alkoxyamino compounds upon alcoholysis.
R1 = Me (2, 9, 16—19), Prn (3, 4, 10, 11, 20—22),
Et (5, 6, 12, 13, 23, 24), Bun (7, 14, 25),
nꢀC12H25 (8, 15, 26)
R
R
R
2 = Me (16, 20, 21, 23—26), Et (17 (from EtCO2K)), Pri (18),
Ph (19, 22)
3 = Me (2—4, 9—11, 16—22), CH2Nphꢀ1 (5, 12, 23),
H (6—8, 13—15, 24—26)
4 = Me (2, 3, 9, 10, 16—20), H (4—8, 11—15, 21—26)
sized these compounds, which are very unstable in pure
form, by the reactions of Nꢀalkoxyureas 3—8 with ButOCl.
NꢀAcyloxyꢀNꢀalkoxyureas 16—23 were prepared as yelꢀ
lowish liquids. N´ꢀUnsubstituted NꢀacetoxyꢀNꢀalkoxyꢀ
ureas 24—26 represent colorless crystalline compounds.
Most of these compounds are rather unstable at 20 °C.
However, these compounds can be stored at –5 °C for up
to 2 months.
In the earlier study of NꢀalkoxyꢀNꢀchlorocarbamates,
attempts to carry out the nucleophilic replacement of the
chlorine atom by an alkoxy group under conditions of
alcoholysis in the presence of Et3N failed.7 In the present
study, NꢀacyloxyꢀNꢀalkoxycarbamates 31—36 were synꢀ
thesized for the first time in high yields by the reactions of
NꢀalkoxyꢀNꢀchlorocarbamates 27—30 with Na(K) salts
of carboxylic acids in MeCN (Scheme 3).
Alcoholysis of NꢀacyloxyꢀNꢀalkoxyureas 16—26 with
primary alcohols (methanol, ethanol, nꢀpropanol) at
20—25 °C selectively afforded the corresponding N,Nꢀdiꢀ
Table 1. N,NꢀDialkoxyureas R3R4NC(O)N(OR1)OR5 40—49
prepared by alcoholysis of NꢀacyloxyꢀNꢀalkoxyureas
Run Starting Alcohol
Ta/°C
Reacꢀ
tion
Reacꢀ Yield
comꢀ
tion
(%)
pound
time/h product
1
2
3
4
5
6
7
8
16
20
17
18
21
22
23
24
25
25
26
21
20
20
20
PrnOH
MeOH
EtOH
PrnOH
MeOH
MeOH
MeOH
MeOH
MeOH
EtOH
MeOH
PriOH
PriOH
PriOH
PriOH
30
20
25—30
25—30
25
20
22
20
30
30
20
20
20
20
82
264
55
217
255
169
45
92
103
30
40
40
41
40
42
42
43
44
45
46
81.5
80.1
97.4
95.4
92.2
56.0
99.5
88.1
92.2
88.4
95.2
71.0
75.4 b
91.9
25.5
Scheme 3
9
10
11
12
13
14
15
142
960 (40 d) 47
450
527
48
49
R1 = Me (27, 28, 31—33), Et (29, 30, 34—36)
R
R
2 = Me (27, 29, 31, 32, 34, 35), nꢀC8H17 (28, 33), Pri (30, 36)
3 = Me (31, 33, 34, 36), Et (32 (from EtCO2K)), Ph (35)
1224 (51 d) 49
49
5
a Reaction temperature.
b With an admixture of the starting compound, the 49/20 ratio
was ∼3 (1H NMR data).
The resulting products are colorless liquids, which can
be stored without noticeable decomposition at 20 °C for
up to 2 days (except for compound 35) or at –5 °C for

Synthesis and alcoholysis of urea derivatives
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
2253
alkoxyureas 40—47 (Table 1, runs 1—11). In addition,
alcoholysis gave rise to the corresponding carboxylic acid,
which was identified by 1H NMR spectroscopy of the
reaction mixtures and by GLC (Scheme 5).
Methyl NꢀacetoxyꢀNꢀnꢀoctyloxycarbamate (33) was
transformed into the corresponding NꢀmethoxyꢀNꢀnꢀ
octyloxycarbamate (51) upon methanolysis for 3 days
(20 °C). Ethanolysis giving rise to methyl N,Nꢀdialkoxyꢀ
carbamate (52) was brought to completion within 120 days
(Scheme 7).
Scheme 5
Scheme 7
R1 = Me (40, 41), Et (43, 44), Prn (42, 48, 49),
Bun (45, 46), nꢀC12H25 (47)
R
R
R
3 = H (44—47), Me (40—42, 48, 49), CH2Nphꢀ1 (43)
4 = H (42—48), Me (40, 41, 49)
5 = Me (42—45, 47), Et (41, 46), Prn (40), Pri (48, 49)
X = MeOC(O)
i. 3 days. ii. 120 days.
Alcoholysis of NꢀacyloxyꢀNꢀalkoxyureas with propanꢀ
2ꢀol under standard conditions requires longer time.
For example, NꢀacetoxyꢀNꢀnꢀpropoxyꢀN´,N´ꢀsubstituted
ureas 20 and 21 reacted with propanꢀ2ꢀol to give Nꢀisoꢀ
propoxyꢀNꢀnꢀpropoxyꢀN´,N´ꢀdisubstituted ureas 48 and
49 in only 71—75% yields even after 22 days (see Table 1,
runs 12 and 13, respectively). The complete conversion
was achieved only after 51 days (see Table 1, run 14).
Compound 20 was completely consumed upon refluxing
in propanꢀ2ꢀol for 5 h; however, product 49 was prepared
in much lower yield (see Table 1, run 15). Upon storage
in tertꢀbutyl alcohol for 70 h, NꢀacetoxyꢀNꢀnꢀpropoxyurea
20 remained intact, its recovery was ∼93%. An analogous
steric hindrance to alcoholysis with tertꢀbutyl alcohol was
observed for NꢀalkoxyꢀNꢀchloroamines2b and Nꢀalkoxyꢀ
NꢀchloroꢀN´,N´ꢀdimethylureas.6
Methanolysis of ethyl NꢀacetoxyꢀNꢀmethoxyꢀ
carbamate (34) afforded ethyl N,Nꢀdimethoxycarbamate
(53) along with ethyl methyl carbonate and ethyl
Nꢀmethoxycarbamate (54) (Scheme 8).
Scheme 8
Alcoholysis of NꢀacyloxyꢀNꢀalkoxycarbamates is
also accompanied by the replacement of the Nꢀacyloxy
group by the alkoxy group. Methanolysis of methyl
NꢀacyloxyꢀNꢀmethoxycarbamates 31 and 32 afforded meꢀ
thyl N,Nꢀdimethoxycarbamate (50) in satisfactory yields
(Scheme 6).
X = EtOC(O)
It should be noted that the nucleophilic substitution at
the nitrogen atom to form N,Nꢀdimethoxyurethane 53 is
not dominant and proceeds, apparently, according to both
the SN1 and SN2 mechanisms. Redox transformations givꢀ
ing rise to Nꢀmethoxyurethane 54 are not predominating
reactions as well. Apparently, the main process involves
the fragmentation of the nitrenium cation, which is genꢀ
erated from compound 34, to produce the more stable
ethoxycarbonyl cation (Scheme 9).
Scheme 6
Storage of compounds 31 and 34 in tertꢀbutyl alcohol
did not afford N,Nꢀdialkoxycarbamates. Storage of comꢀ
X = MeOC(O)
R = Me (31), Et (32)

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Shtamburg et al.
Scheme 9
Scheme 12
R = MeO(O)CCMe2—
in an aprotic medium also failed. Thus treatment of comꢀ
pound 38 with MeONa in DME gave rise to a mixture of
methyl and ethyl benzoates (Scheme 13).
Scheme 13
pound 34 in propanꢀ2ꢀol gave rise to urethane 54 and
hydrazine 55 (Scheme 10).
Scheme 10
Methyl benzoate was generated, apparently, as a reꢀ
sult of the attack of MeO– at the carbonyl fragment of the
benzoyl group. Ethyl benzoate was produced due to miꢀ
gration of the benzoyl group from the nitrogen atom to
the adjacent oxygen atom through the soꢀcalled Heteroꢀ
atomic Rearrangement on Nitrogen (HERON) typical of
NꢀacyloxyꢀNꢀalkoxybenzamides.12
Methanolysis of ethyl NꢀacetoxyꢀNꢀisopropoxycarꢀ
bamate (36) produced ethyl NꢀisopropoxyꢀNꢀmethoxyꢀ
carbamate (56) and ethyl methyl carbonate in similar
yields (Scheme 11).
Thus, a convenient procedure for the preparation of
various NꢀacyloxyꢀNꢀalkoxy compounds involves the reꢀ
actions of NꢀalkoxyꢀNꢀchloro compounds containing the
anionꢀmobile chlorine atom with sodium carboxylates in
MeCN. Alcoholysis of NꢀacyloxyꢀNꢀalkoxy compounds
can involve the nucleophilic substitution at the nitrogen
atom as well as redox processes and elimination dependꢀ
ing on the nature of the third substituent at the nitrogen
atom and the alcohol.
Scheme 11
Experimental
The 1H NMR spectra were recorded on a Varian VXPꢀ300
spectrometer (300 MHz, Me4Si as the internal standard) and a
Teslaꢀ567A spectrometer (100 MHz, (Me3Si)2O as the internal
standard); the chemical shifts are given in the δ scale; the spinꢀ
spin coupling constants are given in Hz. The IR spectra were
measured on a URꢀ20 spectrometer in a thin layer. The mass
spectra were obtained on a Kratos MS 890 instrument using
chemical ionization (CI, isobutane as the reagent gas) and elecꢀ
tron impact (EI, 70 eV). The GLC analysis was carried out on a
Tsvetꢀ5 chromatograph (flame ionization detector, 2400×3ꢀmm
glass column, 5% SEꢀ30 on Chromaton NꢀAW). The solvents
were purified according to standard procedures: MeCN was disꢀ
tilled from P2O5, Et2O and PhH were distilled from Na, and
MeOH and EtOH were distilled from Ca. Sodium carboxylates
were dried in vacuo (1 Torr) at 100 °C.
Methanolysis of NꢀacetoxyꢀNꢀmethoxyamine 1 gave
rise to N,Nꢀdimethoxyamine 57 (Scheme 12).
Unlike alcoholysis of NꢀacyloxyꢀNꢀalkoxy derivaꢀ
tives of ureas, carbamates, and amines, methanolysis of
NꢀacetoxyꢀNꢀethoxybenzamide 38 did not afford nucleoꢀ
philic substitution products at the nitrogen atom at all and
only methyl benzoate and benzoic acid were isolated. An
attempt to replace the acetoxy group by the methoxy group

Synthesis and alcoholysis of urea derivatives
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
2255
Methyl 2ꢀ(NꢀacetoxyꢀNꢀmethoxyamino)ꢀ2ꢀmethylpropionate
(1) was prepared according to a known procedure.5
N´ꢀMethoxyꢀN,Nꢀdimethylurea (2) and NꢀchloroꢀNꢀ
methoxyꢀN´,N´ꢀdimethylyurea (9) were prepared according to
procedures described earlier.6
NꢀnꢀButoxyurea (7) was prepared analogously to comꢀ
pound 8 from BunONH2, NaOCN, and AcOH in a yield of 82%
as colorless crystals, m.p. 109—111 °C (CHCl3). 1H NMR
(300 MHz, CDCl3): 0.94 (t, 3 H, CH2Me, J = 6.5 Hz); 1.39
(sext, 2 H, CH2CH2Me, J = 6.5 Hz); 1.65 (quint, 2 H,
OCH2CH2CH2, J = 6.5 Hz); 3.83 (t, 2 H, OCH2CH2, J =
6.5 Hz); 5.72 (s, 2 H, NH2); 8.00 (s, 1 H, NHO). Found (%):
C, 45.19; H, 8.98; N, 21.06. C5H12N2O2. Calculated (%):
C, 45.44; H, 9.15; N, 21.20.
N,NꢀDimethylꢀN´ꢀnꢀpropoxyurea (3) was prepared from
dimethylcarbamoyl chloride and propoxyamine analogously to
compound 2 6 in 67% yield as a colorless liquid, b.p. 117—118 °C
20
(2 Torr), nD 1.4650. 1H NMR (300 MHz, CDCl3): 0.95 (t,
3 H, CH2CH2Me, J = 7.2 Hz); 1.67 (sext, 2 H, CH2CH2Me, J =
7.2 Hz); 2.91 (s, 6 H, NMe2); 3.81 (t, 2 H, NOCH2, J = 7.2 Hz);
7.41 (s, 1 H, NHO). Found (%): C, 49.16; H, 9.72; N, 19.08.
C6H14N2O2. Calculated (%): C, 49.30; H, 9.65; N, 19.16.
NꢀMethylꢀN´ꢀnꢀpropoxyurea (4). A solution of MeNCO
(1.50 g, 26.3 mmol) in Et2O (6 mL) was added dropwise to a
solution of propoxyamine (1.98 g, 26.3 mmol) in Et2O (10 mL)
and the reaction mixture was kept at 20 °C for 6 days. The
precipitate that formed was filtered off and the solution was
concentrated in vacuo (10 Torr). Compound 4 was obtained in a
yield of 3.15 g (90.5%) as a colorless liquid, nD20 1.4550. 1H NMR
(300 MHz, CDCl3): 0.95 (t, 3 H, CH2CH2Me, J = 7 Hz); 1.67
(sext, 2 H, CH2CH2Me, J = 7 Hz); 2.86 (br.s, 3 H, NMe); 3.77
(t, 2 H, NOCH2, J = 7 Hz); 5.73 (s, 1 H, NH); 7.61 (s, 1 H,
NHO). Found (%): C, 45.67; H, 8.95; N, 21.46. C5H12N2O2.
Calculated (%): C, 45.44; H, 9.15; N, 21.20.
Synthesis of NꢀalkoxyꢀNꢀchloroureas 10—15 (general proꢀ
cedure). A solution of ButOCl (0.28 g, 2.6 mmol) in CH2Cl2
(3 mL) was added to a solution of Nꢀalkoxyurea 3—8 (1.7 mmol)
in CH2Cl2 (5 mL) at –30 °C. The reaction mixture was kept at
20 °C for 0.5 h, the solvent was removed in vacuo, and the
residue was kept at 1 Torr to prepare compounds 10—15.
NꢀChloroꢀN´,N´ꢀdimethylꢀNꢀnꢀpropoxyurea (10), yield
25
97.8%, yellow liquid, nD 1.4680, unstable at 20 °C. 1H NMR
(100 MHz, CCl4): 0.93 (t, 3 H, OCH2CH2Me, J = 6.7 Hz); 1.69
(sext, 2 H, OCH2CH2Me, J = 6.7 Hz); 3.00 (s, 6 H, NMe2);
3.97 (t, 2 H, OCH2CH2Me, J = 6.7 Hz). Found (%): Cl, 19.51.
C6H13ClN2O2. Calculated (%): Cl, 19.63.
NꢀChloroꢀN´ꢀmethylꢀNꢀnꢀpropoxyurea (11), yield 98.5%,
yellow liquid, nD20 1.4720. 1H NMR (100 MHz, CCl4): 0.97 (t,
3 H, CH2CH2Me, J = 7 Hz); 1.71 (sext, 2 H, CH2CH2Me, J =
7 Hz); 2.85 (d, 3 H, MeN, J = 4.7 Hz); 3.93 (t, 2 H, NOCH2,
J = 7 Hz); 6.60 (br.s, 1 H, NH). Found (%): Cl, 21.08.
C5H11ClN2O2. Calculated (%): Cl, 21.28.
NꢀChloroꢀNꢀethoxyꢀN´ꢀ(1ꢀnaphthyl)methylurea (12), yield
100%, yellowish viscous liquid. 1H NMR (300 MHz, CDCl3):
1.21 (t, 3 H, OCH2Me, J = 7 Hz); 4.04 (q, 2 H, OCH2Me, J =
7 Hz); 4.95 (d, 2 H, CH2NH, J = 5.7 Hz); 6.42 (br.s, 1 H, NH);
7.40—7.61 (m, 4 H, C(3)H, C(5)H, C(6)H, C(7)H); 7.83—7.93
(m, 2 H, C(2)H, C(4)H); 8.00 (d, 1 H, C(8)H, J = 8.1 Hz).
Found (%): Cl, 12.43. C14H15ClN2O2. Calculated (%): Cl, 12.72.
NꢀChloroꢀNꢀethoxyurea (13), yield 98%, viscous colorless
liquid. 1H NMR (300 MHz, CDCl3): 1.24 (t, 3 H, OCH2Me,
J = 6.9 Hz); 4.11 (q, 2 H, OCH2Me, J = 6.9 Hz); 5.31 (s, 2 H,
NH2). Found (%): Cl, 25.20. C3H7ClN2O2. Calculated (%):
Cl, 25.59.
NꢀEthoxyꢀN´ꢀ(1ꢀnaphthyl)methylurea (5). A solution of
ethoxyamine (1.09 g, 17.8 mmol) in PhH (3 mL) was added to a
solution of 1ꢀnaphthylmethyl isocyanate (2.11 g, 11.5 mmol) in
PhH (11 mL) and the reaction mixture was kept at 20 °C for
2 days. The precipitate that formed was filtered off and washed
with PhH (5 mL). Compound 5 was prepared in a yield of
1
2.09 g (74%) as colorless crystals, m.p. 145—146 °C. H NMR
(300 MHz, DMSOꢀd6): 1.16 (t, 3 H, OCH2Me, J = 7 Hz); 3.75
(q, 2 H, OCH2Me, J = 7 Hz); 4.73 (d, 2 H, CH2NH, J =
6.3 Hz); 7.37—7.57 (m, 5 H, C(3)H, C(5)H, C(6)H, C(7)H,
and NH); 7.83 (d, 1 H, C(4)H, J = 8.1 Hz); 7.93—7.96 (m, 1 H,
C(2)H); 8.16—8.18 (m, 1 H, C(8)H); 9.14 (s, 1 H, NHO).
Found (%): C, 68.73; H, 6.51; N, 11.38. C14H16N2O2. Calcuꢀ
lated (%): C, 68.83; H, 6.60; N, 11.47.
NꢀnꢀDodecyloxyurea (8). Sodium cyanate (0.97 g,
18.9 mmol) was added portionwise with stirring to a solution of
nꢀdodecyloxyamine (0.75 g, 3.7 mmol) in AcOH (8 mL). The
reaction mixture was stirred for 2 h and kept for 10 h. Then
AcOH was removed in vacuo (1 Torr), the residue was extracted
with CH2Cl2 (50 mL), and CH2Cl2 (40 mL) was distilled off
from the extract. The precipitate that formed was filtered off and
washed with hexane (10 mL). Urea 8 was prepared in a yield of
NꢀnꢀButoxyꢀNꢀchlorourea (14), yield 98%, colorless crysꢀ
tals, m.p. 24—26 °C (with decomp.). 1H NMR (100 MHz, CCl4):
0.96 (t, 3 H, CH2Me, J = 6.3 Hz); 1.1—1.8 (m, 4 H,
CH2CH2Me); 3.96 (t, 2 H, OCH2, J = 6.3 Hz); 6.2 (s, 1 H,
NH); 7.20 (s, 1 H, NH). Found (%): C, 35.82; H, 6.44; N, 16.81.
C5H11ClN2O2. Calculated (%): C, 36.05; H, 6.65; N, 16.81.
NꢀChloroꢀNꢀnꢀdodecyloxyurea (15), yield 100%, colorless
solid, m.p. 69—72 °C. 1H NMR (300 MHz, CDCl3): 0.88 (t, 3 H,
Me, J = 6.8 Hz); 1.14—1.47 (m, 18 H, NOCH2CH2(CH2)9Me);
1.69 (quint, 2 H, NOCH2CH2, J = 6.8 Hz); 4.04 (t, 2 H,
NOCH2, J = 6.8 Hz); 6.15 (br.s, 1 H, NH); 6.31 (br.s, 1 H,
NH). Found (%): Cl, 12.59. C13H27ClN2O2. Calculated (%):
Cl, 12.72.
Synthesis of NꢀacyloxyꢀNꢀalkoxyureas 16—26 (general proꢀ
cedure). A mixture of a solution of NꢀalkoxyꢀNꢀchlorourea 9—15
(8 mmol) and R2COONa (20 mmol) in MeCN (20 mL) was
stirred at 20 °C for 25 h (in the synthesis of compound 26, for
58 h). The precipitate that formed was filtered off and washed
with Et2O. The filtrate was concentrated in vacuo (20 Torr) and
the residue was extracted with benzene (15 mL). The benzene
extract was concentrated in vacuo and the residue was kept at
20 °C and 2 Torr for 0.5 h.
1
0.61 g (67%) as colorless crystals, m.p. 124—125 °C. H NMR
(300 MHz, CDCl3): 0.88 (t, 3 H, Me, J = 7.2 Hz); 1.23—1.40
(m, 18 H, OCH2CH2(CH2)9Me); 1.64 (quint, 2 H, OCH2CH2,
J = 7.2 Hz); 3.84 (t, 2 H, OCH2, J = 7.2 Hz); 5.56 (s, 2 H,
NH2); 7.66 (s, 1 H, NHO). Found (%): N, 11.51. C13H28N2O2.
Calculated (%): N, 11.46. From the CH2Cl2 filtrate, urea 8 was
additionally isolated in a yield of 0.28 g (30.7%) by precipitation
with hexane.
NꢀEthoxyurea (6) was synthesized analogously to compound
8 from EtONH2, NaOCN, and AcOH in a yield of 52% as
colorless crystals, m.p. 85—86 °C. 1H NMR (300 MHz, CDCl3):
1.27 (t, 3 H, OCH2Me, J = 7 Hz); 3.93 (q, 2 H, OCH2Me, J =
7 Hz); 5.64 (s, 2 H, NH2); 7.88 (s, 1 H, NHO). Found (%):
N, 26.95. C3H8N2O2. Calculated (%): N, 26.91.

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Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
Shtamburg et al.
NꢀAcetoxyꢀNꢀmethoxyꢀN´,N´ꢀdimethylurea (16), yield
87.0%, yellowish liquid, b.p. 64—65 °C (1 Torr) (with decomp.),
CDCl3): 0.95 (t, 3 H, OCH2CH2Me, J = 7.2 Hz); 1.74 (sext,
2 H, OCH2CH2Me, J = 7.2 Hz); 2.94 (d, 3 H, NHMe, J =
5.1 Hz); 4.12 (t, 2 H, OCH2CH2Me, J = 7.2 Hz); 6.23 (br.s,
1 H, NH); 7.47 (t, 2 H, C(3)H, C(5)H, J = 7.2 Hz); 7.61 (t, 1 H,
C(4)H, J = 7.2 Hz); 8.07 (d, 2 H, C(2)H, C(6)H, J = 7.2 Hz).
MS (CI), m/z (Irel (%)): 253 [M + H]+ (100); 252 M+ (20.8);
106 (5.5); 105 (37.8); 90 (6.2); 78 (8.5). Found (%): C, 57.40;
H, 6.55; N, 10.98. C12H16N2O4. Calculated (%): C, 57.13;
H, 6.39; N, 11.10.
nD 1.4540. 1H NMR (300 MHz, CDCl3): 2.16 (s, 3 H,
25
O2CMe); 3.03 (s, 3 H, NMe2); 3.85 (s, 3 H, NOMe). MS (CI),
m/z (Irel (%)): 175 [M – H]+ (5.4); 162 (3.3); 161 (4.2); 160
(3.6); 149 (10.7); 146 (24.6); 133 (4.0); 132 (8.2); 130 (13.5);
129 (12.3); 119 (10.6); 118 (13.1); 117 (51.4); 104 (9.9); 89
(18.3); 88 (18.7); 85 (30.1); 72 (100); 61 (25.8); 45 (94.5).
Found (%): C, 40.67; H, 6.83; N, 15.67. C6H12N2O4. Calcuꢀ
lated (%): C, 40.91; H, 6.87; N, 15.90.
NꢀAcetoxyꢀNꢀethoxyꢀN´ꢀ(1ꢀnaphthyl)methylurea (23), yield
1
NꢀMethoxyꢀN´,N´ꢀdimethylꢀNꢀpropionyloxyurea (17), yield
89.9%, yellowish liquid, b.p. 62 °C (2 Torr) (with decomp.),
nD20 1.4529. 1H NMR (300 MHz, CDCl3): 1.21 (t, 3 H, CH2Me,
J = 7.5 Hz); 2.45 (q, 2 H, CH2Me, J = 7.5 Hz); 3.04 (s, 6 H,
NMe2); 3.86 (s, 3 H, NOMe). MS (CI), m/z (Irel (%)): 190 M+
(12.0); 189 (6.6); 175 (5.3), 174 (3.5); 161 (5.6); 159 (3.7); 158
(5.5); 146 (21.5); 133 (5.7); 130 (11.0); 119 (14.5); 118 (13.6);
117 (61.0); 104 (10.4); 89 (14.0); 85 (23.7); 75 (19.0); 72 (100);
56 (17.3); 45 (87.9); Found (%): C, 44.38; H, 7.50; N, 14.44.
C7H14N2O4. Calculated (%): C, 44.20; H, 7.42; N, 14.73.
NꢀIsobutyroyloxyꢀNꢀmethoxyꢀN´,N´ꢀdimethylyurea (18) was
prepared after additional purification by stirring a pentane soluꢀ
tion with aqueous NaHCO3, the yield was 78.3%, yellowish
liquid, nD20 1.4462. 1H NMR (300 MHz, CDCl3): 1.24 (d, 6 H,
CHMe2, J = 6.9 Hz); 2.69 (sept, 1 H, CHMe2, J = 6.9 Hz); 3.03
(s, 6 H, NMe2); 3.85 (s, 3 H, NOMe). MS (EI, 70 eV),
m/z (Irel (%)): 204 [M]+ (1.1); 189 (2.9); 173 (1.5); 73 (36.4); 72
(100); 71 (33.8); 44 (73.5); 43 (91.9). Found (%): C, 47.32;
H, 7.98; N, 13.60. C8H16N2O4. Calculated (%): C, 47.05;
H, 7.90; N, 13.72.
NꢀBenzoyloxyꢀNꢀmethoxyꢀN´,N´ꢀdimethylurea (19), yield
77.1%, colorless viscous liquid, nD20 1.5250. 1H NMR (300 MHz,
CDCl3): 3.07 (br.s, 6 H, NMe2); 3.96 (s, 3 H, NOMe); 7.47 (t,
2 H, C(3)H, C(5)H, J = 7.5 Hz); 7.61 (t, 1 H, C(4)H, J =
7.5 Hz); 8.09 (d, 2 H, C(2)H, C(6)H, J = 7.5 Hz). MS
(EI, 70 eV), m/z (Irel (%)): 238 [M]+ (0.2); 208 (1.1); 192 (1.8);
149 (9.2); 148 (30.9); 106 (36.7); 105 (100); 77 (94.0); 72 (97.0).
Found (%): C, 55.71; H, 6.01; N, 11.52. C11H14N2O4. Calcuꢀ
lated (%): C, 55.46; H, 5.92; N, 11.76.
98.1%, viscous yellowish liquid. H NMR (300 MHz, CDCl3):
1.20 (t, 3 H, OCH2Me, J = 7 Hz); 2.19 (s, 3 H, O2CMe); 4.07
(q, 2 H, OCH2Me, J = 7 Hz); 4.91 (d, 2 H, CH2NH, J = 6.1 Hz);
6.41 (br.s, 1 H, NH); 7.25—7.70 (m, 4 H, C(3)H, C(5)H, C(6)H,
C(7)H); 7.83—7.93 (m, 2 H, C(2)H, C(4)H); 7.99 (d, 1 H,
C(8)H, J = 8 Hz). Found (%): C, 63.79; H, 6.21; N, 9.14.
C16H18N2O4. Calculated (%): C, 63.57; H, 6.00; N, 9.27.
NꢀAcetoxyꢀNꢀethoxyurea (24), yield 80.8%, colorless crysꢀ
tals, m.p. 93—95 °C. 1H NMR (300 MHz, CDCl3) 1.32 (t, 3 H,
OCH2Me, J = 7 Hz); 2.18 (s, 3 H, O2CMe); 4.14 (q, 2 H,
OCH2Me, J = 7 Hz); 6.06 (br.s, 2 H, NH2). Found (%): C, 37.30;
H, 6.31; N, 17.15. C5H10N2O4. Calculated (%): C, 37.04;
H, 6.22; N, 17.28.
NꢀAcetoxyꢀNꢀnꢀbutoxyurea (25), yield 84.4%, colorless crysꢀ
tals, m.p. 53—55 °C (hexane). 1H NMR (300 MHz, CDCl3):
0.95 (t, 3 H, CH2Me, J = 7.5 Hz); 1.38 (sext, 2 H, CH2CH2Me,
J = 7.5 Hz); 1.67 (quint, 2 H, OCH2CH2CH2Me, J = 7.5 Hz);
2.19 (s, 3 H, O2CMe); 4.09 (t, 2 H, OCH2CH2, J = 7.5 Hz);
6.11 (br.s, 2 H, NH2). IR, ν/cm–1: 1790 (C=O); 1730 (C=O).
MS (CI), m/z (Irel (%)): 191 [M + H]+ (11.2); 190 [M]+
(100); 159 (7.7); 134 (21.5); 131 (5.0); 117 (15.2); 103 (51.4).
Found (%): C, 44.93; H, 7.72; N, 14.60. C7H14N2O4. Calcuꢀ
lated (%): C, 44.20; H, 7.42; N, 14.73.
NꢀAcetoxyꢀNꢀnꢀdodecyloxyurea (26), yield 84.5%, colorꢀ
less crystals, m.p. 63—64 °C (hexane). 1H NMR (300 MHz,
CDCl3): 0.88 (t, 3 H, Me, J = 6.9 Hz); 1.10—1.20 (m, 18 H,
NOCH2CH2(CH2)9Me); 1.68 (quint, 2 H, NOCH2CH2, J =
6.9 Hz); 2.18 (s, 3 H, O2CMe); 4.08 (t, 2 H, NOCH2CH2,
J = 6.9 Hz); 5.94 (s, 2 H, NH2). Found (%): C, 59.65;
H, 10.12; N, 9.07. C15H30N2O4. Calculated (%): C, 59.58;
H, 10.00; N, 9.26.
NꢀAcetoxyꢀN´,N´ꢀdimethylꢀNꢀnꢀpropoxyurea (20), yield
90.9%, yellowish liquid, nD 1.4561. 1H NMR (300 MHz,
20
CDCl3): 0.95 (t, 3 H, OCH2CH2Me, J = 7.2 Hz); 1.68 (sext,
2 H, OCH2CH2Me, J = 7.2 Hz); 2.15 (s, 3 H, O2CMe); 3.04 (s,
6 H, NMe2); 4.04 (t, 2 H, OCH2CH2Me, J = 7.2 Hz). IR,
ν/cm–1: 1784 (C=O), 1732 (C=O). MS (CI), m/z (Irel (%)): 206
[M + 2 H]+ (17.3); 205 [M + H]+ (100); 204 M+ (19.4); 203
(11.9); 174 (15.3); 160 (16.0); 148 (10.8); 132 (25.8). Found (%):
C, 47.12; H, 8.02; N, 13.65. C8H16N2O4. Calculated (%):
C, 47.05; H, 7.90; N, 13.72.
Methyl NꢀchloroꢀNꢀmethoxycarbamate (27) was synthesized
according to a procedure described earlier.7
Synthesis of NꢀalkoxyꢀNꢀchlorocarbamates 28—30 (general
procedure). A solution of ButOCl (10 mmol) in CH2Cl2 (3 mL)
was added to a solution of the corresponding Nꢀalkoxycarbamate
(5 mmol) in CH2Cl2 (6 mL) at –20 °C. The reaction mixture
was kept at 20 °C for 0.5 h (in the case of 30, for 2 h), concenꢀ
trated in vacuo (10 Torr), and kept at 3 Torr for 10 min.
Methyl NꢀchloroꢀNꢀnꢀoctyloxycarbamate (28), yellowish liqꢀ
NꢀAcetoxyꢀN´ꢀmethylꢀNꢀnꢀpropoxyurea (21), yield 92.0%,
colorless liquid, nD 1.4549. 1H NMR (300 MHz, CDCl3):
uid, nD 1.4520. 1H NMR (100 MHz, CCl4): 0.88 (t, 3 H,
20
20
0.96 (t, 3 H, OCH2CH2Me, J = 7.5 Hz); 1.71 (sext, 2 H,
OCH2CH2Me, J = 7.5 Hz); 2.18 (s, 3 H, O2CMe); 2.90 (d, 3 H,
NHMe, J = 4.8 Hz); 4.04 (t, 2 H, OCH2CH2Me, J = 7.5 Hz);
6.16 (s, 1 H, NH). IR, ν/cm–1: 1795 (C=O), 1730 (C=O). MS
(CI), m/z (Irel (%)): 192 [M + 2 H]+ (8.1); 191 [M + H]+ (82.4);
189 (0.6); 175 (3.0); 147 (11.2); 133 (83.8); 131 (100). Found (%):
C, 44.34; H, 7.23; N, 14.61. C7H14N2O4. Calculated (%):
C, 44.20; H, 7.42; N, 14.73.
(CH2)7Me, J = 7 Hz); 1.05—1.93 (m, 12 H, OCH2(CH2)6Me);
3.83 (s, 3 H, CO2Me); 3.89 (t, 2 H, NOCH2, J = 7 Hz).
Found (%): Cl, 14.72. C10H20ClNO3. Calculated (%): Cl, 14.91.
Ethyl NꢀchloroꢀNꢀmethoxycarbamate (29), yellowish liquid,
b.p. 45—46 °C (3 Torr), nD241.4341. 1H NMR (300 MHz,
CDCl3): 1.37 (t, 3 H, CO2CH2Me, J = 7 Hz); 3.81 (s, 3 H,
NOMe); 4.35 (q, 2 H, CO2CH2Me, J = 7 Hz). Found (%):
Cl, 22.80. C4H8ClNO3. Calculated (%): Cl, 23.09.
NꢀBenzoyloxyꢀN´ꢀmethylꢀNꢀnꢀpropoxyurea (22), yield
86.2%, colorless viscous liquid, nD20 1.5171. 1H NMR (300 MHz,
Ethyl NꢀchloroꢀNꢀisopropoxycarbamate (30), yellowish
liquid. 1H NMR (300 Hz, CDCl3): 1.28 (d, 6 H, NOCHMe2,

Synthesis and alcoholysis of urea derivatives
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
2257
J = 6.3 Hz); 1.36 (t, 3 H, CO2CH2Me, J = 7 Hz); 4.31 (sept,
1 H, NOCHMe2, J = 6.3 Hz); 4.33 (q, 2 H, CO2CH2Me, J =
7 Hz). Found (%): Cl, 19.46. C6H12ClNO3. Calculated (%):
Cl, 19.52.
Synthesis of NꢀacyloxyꢀNꢀalkoxycarbamates 31—36 (genꢀ
eral procedure). A solution of NꢀalkoxyꢀNꢀchlorocarbamate
28—30 (8 mmol) in MeCN (20 mL) was stirred with R3COONa
(26 mmol) at 20 °C for 25 h. The precipitate that formed was
filtered off and washed with Et2O. The filtrate was concentrated
in vacuo (20 Torr). The residue was extracted with Et2O (20 mL),
the extract was concentrated in vacuo, and the residue was kept
at 3 Torr and 20 °C for 0.5 h.
J = 7.2 Hz); 4.33 (sept, 1 H, NOCHMe2, J = 6.3 Hz). Found (%):
C, 46.61; H, 7.35; N 6.59. C8H15NO5. Calculated (%): C, 46.82;
H, 7.37; N, 6.83.
NꢀChloroꢀNꢀethoxybenzamide (37) was synthesized as deꢀ
scribed earlier.9
NꢀAcetoxyꢀNꢀethoxybenzamide (38). A solution of comꢀ
pound 37 (0.505 g, 2.5 mmol) in MeCN (10 mL) was added with
stirring to a solution of AcONa (0.52 g, 6.3 mmol) in MeCN
(10 mL). The reaction mixture was stirred at 20 °C for 25 h. The
precipitate that formed was filtered off and the filtrate was
concentrated in vacuo (17 Torr). The residue was extracted
with benzene (18 mL), the extract was concentrated in vacuo
(17 Torr), and the residue was kept at 3 Torr. Compound 38 was
prepared in a yield of 0.51 g (90.3%) as a yellowish liquid,
Methyl NꢀacetoxyꢀNꢀmethoxycarbamate (31), yield 85.5%,
colorless liquid, b.p. 69—70 °C (3 Torr), nD22 1.4213. H NMR
1
nD 1.5085. 1H NMR (300 MHz, CDCl3): 1.29 (t, 3 H,
24
(300 MHz, C6D6): 1.59 (s, 3 H, CO2Me); 3.30 (s, NOMe); 3.66
(s, 3 H, CO2Me). 1H NMR (300 MHz, CDCl3): 2.19 (s, 3 H,
O2CMe); 3.89 (s, 6 H, CO2Me and NOMe). IR, ν/cm–1: 1805
(C=O); 1780 (C=O). MS (CI), m/z (Irel (%)): 164 [M + H]+
(3.5); 163 [M]+ (9.8); 162 (8.5); 133 (9.9); 106 (7.9); 105 (100);
104 (16.0); 91 (11.3); 89 (13.2); 75 (7.1); 61 (29.6); 58 (48.5); 44
(89.5). Found (%): C, 36.95; H, 5.44; N, 8.53. C5H9NO5. Calꢀ
culated (%) : C, 36.81; H, 5.56; N, 8.59.
OCH2Me, J = 7 Hz); 2.11 (s, 3 H, O2CMe); 4.24 (q, 2 H,
OCH2Me, J = 7 Hz); 7.43 (t, 2 H, C(3)H, C(5)H, J = 6.9 Hz);
7.55 (t, 1 H, C(4)H, J = 6.9 Hz); 7.78 (d, 2 H, C(2)H, C(6)H,
J = 6.9 Hz). This spectrum is identical with the 1H NMR specꢀ
trum of the authentic sample.8
NꢀChloroꢀNꢀethoxytolueneꢀpꢀsulfonamide (39) was preꢀ
pared by chlorination of Nꢀethoxytolueneꢀpꢀsulfonamide14 with
tertꢀbutyl hypochlorite in CH2Cl2 according to a known proceꢀ
Methyl NꢀmethoxyꢀNꢀpropionyloxycarbamate (32), yield
22
30
74.2%, colorless liquid, b.p. 59—60 °C (1 Torr), nD 1.4222.
dure,6 yellowish liquid, nD 1.5332. Found (%): C, 43.01;
1H NMR (300 MHz, CDCl3): 1.16 (t, 3 H, CH2Me, J = 7.5 Hz);
2.40 (q, 2 H, CH2Me, J = 7.5 Hz); 3.82 (s, 6 H, CO2Me and
NOMe). MS (CI), m/z (Irel (%)): 178 [M + H]+ (5.9); 177 [M]+
(0.5); 176 (0.8); 106 (57.0); 105 (11.0); 104 (100). Found (%):
C, 40.94; H, 6.30; N, 7.72. C6H11NO5. Calculated (%): C, 40.68;
H, 6.26; N, 7.91.
H, 4.95; Cl, 14.29. C9H12ClNO3S. Calculated (%): C, 43.29;
H, 4.84; Cl, 14.20.
Reaction of compound 39 with AcONa. A mixture of comꢀ
pound 39 (0.62 g, 2.5 mmol) and AcONa (1.42 g, 17.3 mmol)
was stirred in MeCN (25 mL) at 20 °C for 20 h. The precipitate
that formed was filtered off and the filtrate was concentrated in
vacuo (20 Torr). The residue was extracted with benzene (13 mL).
The extract was concentrated in vacuo and the residue was kept
at 2 Torr. Unconsumed compound 39, which was identified by
1H NMR spectroscopy, was obtained in a yield of 0.55 g (88.7%).
Alcoholysis of NꢀacyloxyꢀNꢀalkoxyureas 16—18 and 20—26
(general procedure). NꢀAcyloxyꢀNꢀalkoxyurea (3 mmol) was disꢀ
solved in an alcohol (10—15 mL) and kept at 20—30 °C (see
Table 1). Then the alcohol was removed in vacuo, the residue
was extracted with ether (30 mL), and the extract was stirred
with a solution of NaHCO3 (1.3 g) in water (1 mL). The organic
phase was separated and concentrated in vacuo. The residue was
kept at 1 Torr and 25—30 °C for 20 min. The yields of products
40—47 are given in Table 1.
Methyl NꢀacetoxyꢀNꢀnꢀoctyloxycarbamate (33), yield 93.4%,
colorless liquid, nD 1.4385. 1H NMR (300 MHz, CDCl3):
20
0.79 (t, 3 H, (CH2)7Me, J = 7 Hz); 1.13—1.33 (m, 10 H,
OCH2CH2(CH2)5Me); 1.58 (quint, 2 H, OCH2CH2, J = 7 Hz);
2.09 and 3.79 (both s, 3 H each, CO2Me); 3.97 (t, 2 H, NOCH2,
J = 7 Hz). IR, ν/cm–1: 1805 (C=O); 1780 (C=O). Found (%):
C, 55.08; H, 8.95; N, 5.20. C12H23NO5. Calculated (%):
C, 55.16; H, 8.87; N, 5.36.
Ethyl NꢀacetoxyꢀNꢀmethoxycarbamate (34), yield 92.3%,
22
yellowish liquid, nD 1.4232. 1H NMR (300 MHz, CDCl3):
1.35 (t, 3 H, CO2CH2Me, J = 7 Hz); 2.19 (s, 3 H, O2CMe); 3.89
(s, 3 H, NOMe); 4.32 (q, 2 H, CO2CH2Me, J = 7 Hz).
IR, ν/cm–1: 1780 (C=O); 1755 (C=O). MS (EI, 70 eV),
m/z (Irel (%)): 177 [M]+ (1.7); 146 (7.5); 119 (12.7); 118
(13.6); 90 (15.7); 75 (23.1); 74 (79.4); 73 (34.7); 72 (11.8); 59
(100); 58 (32.3); 46 (59.5); 45 (67.7); 43 (74.7). Found (%):
C, 40.41; H, 6.31; N, 7.78. C6H11NO5. Calculated (%): C, 40.68;
H, 6.26; N, 7.91.
NꢀMethoxyꢀN´,N´ꢀdimethylꢀNꢀnꢀpropoxyurea (40) colorless
25
liquid, b.p. 95—95.5 °C (1 Torr); nD 1.4449. 1H NMR
(300 MHz, CDCl3): 0.96 (t, 3 H, CH2CH2Me, J = 7.1 Hz); 1.67
(sext, 2 H, CH2CH2Me, J = 7.1 Hz); 3.00 (s, 6 H, NMe2); 3.73
(s, 3 H, NOMe); 3.91 (t, 2 H, NOCH2, J = 7.1 Hz). MS (CI),
m/z (Irel (%)): 177 [M + H]+ (7.7); 175 (6.4); 174 (9.9); 161
(32.8); 160 (11.0); 146 (14.0); 145 (19.0); 133 (11.2); 118 (13.9);
117 (46.5); 116 (29.3); 105 (12.9); 104 (24.3); 103 (40.2); 90
(14.3); 89 (100); 73 (20.7); 72 (23.5). Found (%): C, 47.82;
H, 9.17; N, 15.63. C7H16N2O3. Calculated (%): C, 47.71;
H, 9.15; N, 15.90.
Ethyl NꢀbenzoyloxyꢀNꢀmethoxycarbamate (35), yield 60.5%,
22
yellowish liquid, nD 1.4879, can be stored at –5 °C for no
1
more than one day. H NMR (300 MHz, CDCl3): 1.35 (t, 3 H,
CO2CH2Me, J = 7 Hz); 3.97 (s, 3 H, NOMe); 4.38 (q, 2 H,
CO2CH2Me, J = 7 Hz); 7.49 (t, 2 H, C(3)H, C(5)H, J =
6.9 Hz); 7.64 (t, 1 H, C(4)H, J = 6.9 Hz); 8.11 (d, 2 H, C(2)H,
C(6)H, J = 6.9 Hz). Found (%): C, 55.04; H, 5.70; N, 5.47.
C11H13NO5. Calculated (%): C, 55.23; H, 5.48; N, 5.85.
Ethyl NꢀacetoxyꢀNꢀisopropoxycarbamate (36), yield 98.0%,
NꢀEthoxyꢀNꢀmethoxyꢀN´,N´ꢀdimethylurea (41) was identiꢀ
fied by comparing its 1H NMR spectrum with the spectrum of
the authentic sample.6
22
yellowish liquid, nD 1.4211. 1H NMR (300 MHz, CDCl3):
NꢀMethoxyꢀN´ꢀmethylꢀNꢀnꢀpropoxyurea (42), colorless liqꢀ
20
1.28 (d, 6 H, OCHMe2, J = 6.3 Hz); 1.33 (t, 3 H, CO2CH2Me,
J = 7.2 Hz); 2.17 (s, 3 H, O2CMe); 4.30 (q, 2 H, CO2CH2Me,
uid, b.p. 91—92 °C (1 Torr), nD 1.4491. 1H NMR (300 MHz,
CDCl3): 0.98 (t, 3 H, CH2CH2Me, J = 7.5 Hz); 1.72 (sext, 2 H,

2258
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
Shtamburg et al.
CH2CH2Me, J = 7.5 Hz); 2.87 (d, 3 H, NMe, J = 4.8 Hz); 3.82
(s, 3 H, NOMe); 4.00 (t, 2 H, NOCH2, J = 7.5 Hz); 6.15 (br.s,
1 H, NH). Found (%): C, 44.59; H, 8.86; N, 17.11. C6H14N2O3.
Calculated (%): C, 44.43; H, 8.70; N, 17.27.
1.69 (sext, 2 H, OCH2CH2Me, J = 7.2 Hz); 2.86 (d, 3 H,
NHMe, J = 4 Hz); 3.97 (t, 2 H, OCH2CH2Me, J = 7.2 Hz);
4.30 (sept, 1 H, OCHMe2, J = 6.3 Hz); 6.13 (br.s, 1 H, NH).
MS (EI, 70 eV), m/z (Irel (%)): 190 M+ (6.2); 189 (1.8); 188
(2.0); 133 (14.1); 132 (29.2); 131 (21.4); 130 (68.2); 118 (10.5);
90 (25.4); 89 (35.8); 88 (34.0); 73 (19.3); 59 (21.4); 58 (70.7); 43
(100). Found (%): C, 50.35; H, 9.42; N, 14.81. C8H18N2O3.
Calculated (%): C, 50.51; H, 9.54; N, 14.72.
NꢀIsopropoxyꢀN´,N´ꢀdimethylꢀNꢀpropoxyurea (49), colorless
liquid, nD20 1.4460. 1H NMR (300 MHz, CDCl3): 0.95 (t, 3 H,
OCH2CH2Me, J = 7 Hz); 1.25 (d, 6 H, OCHMe2, J = 6.3 Hz);
1.63 (sext, 2 H, OCH2CH2Me, J = 7 Hz); 3.01 (s, 6 H, NMe2);
3.86 (t, 2 H, OCH2CH2Me, J = 7 Hz); 4.21 (sept, 1 H, OCHMe2,
J = 6.3 Hz). MS (EI, 70 eV), m/z (Irel (%)): 204 M+ (1.1); 146
(3.5); 144 (3.0); 104 (19.4); 101 (18.5); 73 (17.1); 72 (100); 59
(45.8); 57 (12.6); 45 (16.3); 44 (29.2); 43 (24.3). Found (%):
C, 53.03; H, 9.94; N, 13.65. C9H20N2O3. Calculated (%):
C, 52.92; H, 9.87; N, 13.71.
Methyl N,Nꢀdimethoxycarbamate (50). A. A solution of meꢀ
thyl NꢀacetoxyꢀNꢀmethoxycarbamate (31) (0.29 g, 1.8 mmol)
in MeOH (2 mL) was kept at 20 °C for 8 days. Then MeOH was
distilled off in vacuo, the residue was extracted with pentane, the
extract was concentrated, and the residue was distilled in vacuo.
Methyl N,Nꢀdimethoxycarbamate (50) was prepared in a yield
of 0.14 g (58.2%) as a colorless liquid, b.p. 52—55 °C (9 Torr).
1H NMR (300 MHz, CDCl3): 3.83 (s, 6 H, NOMe); 3.88 (s,
3 H, CO2Me). MS (CI), m/z (Irel (%)): 136 [M + H]+ (2.2); 134
[M – H]+ (5.6); 133 (5.8); 105 (43.8); 104 (32.0); 76 (96.4); 61
(56.0); 58 (47.2);46 (27.6); 45 (32.2); 44 (100). Found (%):
C, 35.43; H, 6.81; N, 10.60. C4H9NO4. Calculated (%): C, 35.56;
H, 6.71; N, 10.37.
NꢀEthoxyꢀNꢀmethoxyꢀN´ꢀ(1ꢀnaphthyl)methylurea (43), visꢀ
cous yellowish liquid. 1H NMR (300 MHz, CDCl3): 1.19 (t,
3 H, OCH2Me, J = 6.9 Hz); 3.73 (s, 3 H, NOMe); 4.02 (q, 2 H,
OCH2Me, J = 6.9 Hz); 4.83 (d, 2 H, CH2N H, J = 5.1 Hz); 6.31
(br.s, 1 H, NH); 7.26—7.63 (m, 4 H, C(3)H, C(5)H, C(6)H,
C(7)H); 7.71—7.86 (m, 2 H, C(2)H, C(4)H); 7.95 (d, 1 H,
C(8)H, J = 8 Hz). MS (EI, 70 eV), m/z (Irel (%)): 274 [M]+
(3.5), 243 [M – MeO]+ (19.3), 229 [M – EtO]+ (3.5), 201
(23.7), 200 (63.5), 182 (15.3), 156 (38.0), 155 (11.8), 154 (23.7),
142 (11.5), 141 (56.0), 129 (100), 128 (46.8), 127 (42.7).
Found (%): N, 10.03. C15H18N2O3. Calculated (%): N, 10.21.
NꢀEthoxyꢀNꢀmethoxyurea (44), colorless liquid, nD20 1.4493.
1H NMR (300 MHz, CDCl3): 1.32 (t, 3 H, OCH2Me, J =
7 Hz); 3.83 (s, 3 H, NOMe); 4.12 (q, 2 H, OCH2Me, J = 7 Hz);
5.50 and 5.93 (both s, 1 H each, NH). Found (%): C, 35.93;
H, 7.80; N, 20.69. C4H10N2O3. Calculated (%): C. 35.82;
H, 7.51; N, 20.88.
NꢀnꢀButoxyꢀNꢀmethoxyurea (45), yellowish liquid,
nD25 1.4495. 1H NMR (300 MHz, CDCl3): 0.95 (t, 3H, CH2Me,
J = 7.5 Hz); 1.42 (sext, 2 H, CH2CH2Me, J = 7.5 Hz); 1.67
(quint, 2 H, OCH2CH2CH2, J = 7.5 Hz); 3.81 (s, 3 H, NOMe);
4.04 (t, 2 H, OCH2CH2, J = 7.5 Hz); 6.05 and 6.38 (both s,
1 H each, NH). MS (CI), m/z (Irel (%)): 163 [M + H]+ (5.9),
161 (3.0), 160 (3.0), 146 (3.2), 133 (12.7), 131 (15.4), 119 (6.0),
116 (9.4), 105 (4.6), 104 (21.5), 89 (56.4), 88 (91.1), 77 (42.7),
76.6 (11.1), 75 (48.1), 73 (10.0), 70 (46.4), 61 (56.5), 60 (48.6),
59 (100), 58 (36.6), 56 (70.1), 54 (15.1), 46 (16.0), 45 (57.2), 44
(54.4). Found (%): C, 44.21; H, 8.51; N, 17.38. C6H14N2O3.
Calculated (%): C, 44.43; H, 8.70; N, 17.27.
B. Methanolysis of methyl NꢀmethoxyꢀNꢀpropionyloxyꢀ
carbamate (32) performed under analogous conditions afforded
methyl N,Nꢀdimethoxycarbamate (50) in 61.4% yield.
NꢀnꢀButoxyꢀNꢀethoxyurea (46), yellowish liquid, b.p.
56—58 °C (1 Torr) (with decomp.), nD 1.4465. 1H NMR
Methyl NꢀmethoxyꢀNꢀnꢀoctyloxycarbamate (51). A solution
of methyl NꢀacetoxyꢀNꢀnꢀoctyloxycarbamate (33) (0.28 g,
1.1 mmol) in MeOH (3 mL) was kept at 20 °C for 3 days. Then
MeOH was evaporated in vacuo, the residue was treated with a
mixture of hexane and aqueous NaHCO3. The hexane extract
was separated and concentrated in vacuo. The residue was kept
at 20 °C and 2 Torr for 0.5 h. NꢀMethoxyꢀNꢀnꢀoctyloxyꢀ
carbamate 51 was prepared in a yield of 0.245 g (98%) as a
25
(300 MHz, CDCl3): 0.91 (t, 3 H, O(CH2)3Me, J = 7.5 Hz);
1.27 (t, 3 H, OCH2Me, J = 6.9 Hz); 1.38 (sext, 2 H,
OCH2CH2CH2Me,
J = 7.5 Hz); 1.63 (quint, 2 H,
OCH2CH2CH2, J = 7.5 Hz); 3.99 (t, 2 H, OCH2CH2, J =
7.5 Hz); 4.06 (q, 2 H, OCH2Me, J = 6.9 Hz); 6.01 (br.s, 2 H,
NH2). MS (CI), m/z (Irel (%)): 178 [M + 2 H]+ (10.5), 177
[M + H]+ (100), 163 (12.4), 134 (10.1), 133 (37.0), 131 (25.9),
105 (27.9), 103 (43.7). Found (%): C, 47.54; H, 9.22; N, 15.50.
C7H16N2O3. Calculated (%): C, 47.71; H, 9.15; N, 15.90.
NꢀnꢀDodecyloxyꢀNꢀmethoxyurea (47), colorless crystals,
m.p. 46—49 °C. 1H NMR (300 MHz, CDCl3): 0.88 (t,
20
colorless liquid, nD 1.4345. 1H NMR (300 MHz, CDCl3):
0.88 (t, 3 H, (CH2)7Me, J = 6.9 Hz); 1.24—1.43 (m, 10 H,
OCH2CH2(CH2)5Me); 1.67 (quint, 2 H, OCH2CH2, J =
6.9 Hz); 3.80 (s, 3 H, NOMe); 3.87 (s, 3 H, CO2Me); 4.00 (t,
2 H, NOCH2, J = 6.9 Hz). MS (CI), m/z (Irel (%)): 234 [M + H]+
(3.8); 233 [M]+ (0.6); 232 (0.6); 203 (13.3); 202 (100); 121
(10.9); 111 (37.5); 106 (19.7); 104 (16.2). Found (%): C, 56.51;
H, 10.05; N, 5.82. C11H23NO4. Calculated (%): C, 56.63;
H, 9.94; N, 6.00.
3
H, O(CH2)11Me, J = 7 Hz); 1.20—1.40 (m, 18 H,
OCH2CH2(CH2)9Me); 1.66 (quint, 2 H, NOCH2CH2, J =
7 Hz); 3.83 (s, 3 H, NOMe); 4.04 (t, 2 H, NOCH2, J = 7 Hz);
5.32 (br.s, 1 H, NH); 5.9 (br.s, 1 H, NH). IR, ν/cm–1: 1708
(C=O). MS (EI, 70 eV), m/z (Irel (%)): 274 [M]+ (0.1), 259
[M – Me]+ (0.1), 245 [M – Et]+ (0.1), 113 (8.0), 111 (10.1), 99
(15.5); 86. (11.1), 85 (67.7), 84 (20.0), 71 (83.9), 70 (41.9), 69
(66.0), 68 (24.2), 67 (27.0), 63 (28.2), 58 (31.8), 57 (100), 56
(66.9), 55 (83.0), 54 (24.1). Found (%): C, 61.54; H, 10.95;
N, 10.14. C14H30N2O3. Calculated (%): C, 61.28; H, 11.02;
N, 10.21.
Methyl NꢀethoxyꢀNꢀnꢀoctyloxycarbamate (52) was syntheꢀ
sized as described above by ethanolysis of methyl NꢀacetoxyꢀNꢀ
nꢀoctyloxycarbamate (33) at 20 °C for 120 days. The yield was
20
78.5%, yellowish liquid, nD 1.4348. 1H NMR (300 MHz,
CDCl3): 0.88 (t, 3 H, (CH2)7Me, J = 6.7 Hz); 1.24—1.36 (m,
10 H, OCH2CH2(CH2)5Me); 1.29 (t, 3 H, NOCH2Me, J =
6.9 Hz); 1.66 (quint, 2 H, OCH2CH2, J = 6.7 Hz); 3.85 (s, 3 H,
CO2Me); 3.99 (t, 2 H, NOCH2, J = 6.7 Hz); 4.06 (q, 2 H,
NOCH2Me, J = 6.9 Hz). MS (CI), m/z (Irel (%)): 248 [M + H]+
NꢀIsopropoxyꢀN´ꢀmethylꢀNꢀpropoxyurea (48), colorless liqꢀ
20
uid, nD 1.4472. 1H NMR (300 MHz, CDCl3): 0.97 (t, 3 H,
OCH2CH2Me, J = 7.2 Hz); 1.28 (d, 6 H, OCHMe2, J = 6.3 Hz);

Synthesis and alcoholysis of urea derivatives
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
2259
(10.3); 247 [M]+ (6.3); 229 (4.3); 216 (1.3); 204 (8.2); 202
(31.4); 145 (9.8); 135 (69.2); 120 (51.8); 119 (11.1); 118 (100).
Found (%): C, 58.10; H, 10.27; N, 5.51. C12H25NO4. Calcuꢀ
lated (%): C, 58.27; H, 10.19; N, 5.66.
60 (50.9); 59 (15.8); 58 (17.0); 56 (13.8); 46 (95.3); 45 (37.8); 43
(26.1); 42 (28.8). Found (%): C, 47.22; H, 8.70; N, 7.65.
C7H15NO4. Calculated (%): C, 47.45; H 8.53; N, 7.90.
Ethyl methyl carbonate was found (GLC) in the condensate
in a yield of 0.044 g (38.7%).
Methanolysis of ethyl NꢀacetoxyꢀNꢀmethoxycarbamate (34).
A solution of ethyl NꢀacetoxyꢀNꢀmethoxycarbamate (34) (1.10 g,
6.21 mmol) in MeOH (10 mL) was kept at 20 °C for 98 h. Then
MeOH was distilled off in vacuo (17 Torr) into a cooled trap.
The residue was extracted with pentane (25 mL). The extract
was concentrated and the residue was distilled in vacuo (4 Torr).
Ethyl N,Nꢀdimethoxycarbamate (53) was prepared in a yield of
Methanolysis of NꢀacetoxyꢀNꢀmethoxyamine 1. A solution
of compound 1 (0.48 g, 2.34 mmol) and triethylamine (0.3 g,
3 mmol) in MeOH (5 mL) was kept at 20 °C for 6 days. Then
MeOH was removed in vacuo. The residue was extracted with
Et2O, washed with water, and dried over MgSO4. Then Et2O
was removed in vacuo and the residue was distilled. Methyl
2ꢀ(N,Nꢀdimethoxyamino)ꢀ2ꢀmethylpropionate (57) was preꢀ
pared in a yield of 0.24 g (57.5%) and identified by comparing its
1H NMR spectrum with the spectrum of the authentic sample.2c
Methanolysis of NꢀacetoxyꢀNꢀethoxybenzamide (38). A soꢀ
lution of compound 38 (0.42 g, 1.9 mmol) in MeOH (4 mL) was
kept at 20 °C for 6 days and then the methanol was removed in
vacuo (17 Torr). The residue was fractionated in vacuo. Benzoic
acid and methyl benzoate, which were identified by GLC and
based on the 1H NMR spectra, were obtained in yields of 0.048 g
(20.7%) and 0.124 g (48%), respectively.
Reaction of NꢀacetoxyꢀNꢀethoxybenzamide (38) with MeONa
in dimethoxyethane. A mixture of compound 38 (1.26 g,
5.64 mmol), anhydrous DME (20 mL), and MeONa (0.34 g,
6.25 mmol) was stirred at 20 °C for 36 h and then CO2 was
passed through the reaction mixture. The precipitate that formed
was filtered off, the filtrate was concentrated in vacuo, and the
residue was extracted with Et2O. The ethereal extract was conꢀ
centrated in vacuo and the residue was chromatographed on a
column (Al2O3, hexane—Et2O as the eluent). Methyl and ethyl
benzoates, which were identified by GLC and based on 1H NMR
spectra, were prepared in yields of 0.18 g (23.4%) and 0.26 g
(30.6%), respectively.
25
0.32 g (34%) as a colorless liquid, nD 1.4200. 1H NMR
2
(300 MHz, CDCl3): 1.36 (t, 3 H, MeCH2, J = 7 Hz); 3.83 (s,
6 H, MeO); 4.32 (q, 2 H, CO2CH2Me, 2J = 7 Hz). MS (CI),
m/z (Irel (%)): 150 [M + H]+ (0.5); 149 [M]+ (4.1); 148 (62.4);
118 (44.6); 117 (19.6); 116 (100); 104 (10.2); 76 (9.5); 75 (20.4);
73 (9.0). Found (%): C, 40.35; H, 7.68; N, 9.20. C5H11NO4.
Calculated (%): C, 40.27; H, 7.43; N, 9.39.
After extraction with pentane, the residue was neutralized
with NaHCO3 and extracted with ether (15 mL). The ethereal
extract was concentrated in vacuo to give ethyl Nꢀmethoxyꢀ
carbamate (54) in a yield of 0.054 g (7.3%). Compound 54 was
identified by comparing its 1H NMR spectrum with the specꢀ
trum of the authentic sample.13 In the MeOH condensate colꢀ
lected into a trap, ethyl methyl carbonate was detected (GLC)
in a yield of 0.287 g (44.4%).
tertꢀButanolysis of methyl NꢀacetoxyꢀNꢀmethoxycarbamate
(31). A solution of compound 31 (0.135 g, 0.83 mmol) in ButOH
(3 mL) was kept at 28—30 °C for 7 days and then ButOH was
removed in vacuo (2 Torr, 30 °C). The starting compound 31,
which was identified by 1H NMR spectroscopy, was obtained in
a yield of 0.082 g.
Analogously, ethyl NꢀacetoxyꢀNꢀmethoxycarbamate (34)
was recovered in 82.7% yield after storage in ButOH at 22 °C for
3 days.
This study was financially supported by INTAS (Grant
99ꢀ00157).
Reduction of ethyl NꢀacetoxyꢀNꢀmethoxycarbamate (34) in
propanꢀ2ꢀol. A solution of compound 34 (0.31 g, 1.73 mmol) in
PriOH (5 mL) was kept at 28 °C for 8 days. Then PriOH was
removed in vacuo (20 Torr) and the residue was chromatographed
on a column (Al2O3, hexane—Et2O as the eluent). Compound
55, ethyl Nꢀmethoxycarbamate (54), and compound 34 were
obtained in yields of 0.074 g (36.2%), 0.042 g (20.4%), and
0.02 g (6.5%), respectively. These compounds were identified by
1H NMR spectroscopy. N,N´ꢀDi(ethoxycarbonyl)ꢀN,N´ꢀdiꢀ
methoxyhydrazine (55), colorless liquid, nD20 1.4330, was idenꢀ
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Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
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Received December 24, 2002;
in revised form August 29, 2003