Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate activation

Article abstract of DOI:10.1016/j.crci.2019.03.001

Acylimidodicarbonates obtained from aziridine-2-carboxamides through Davidsen bis-Boc activation react with amine nucleophiles under mild conditions to form tertiary aziridine-2-carboxylic acid amides. NH aziridine-2-carboxylic acid amides were obtained by hydrogenolythic deprotection of N-Cbz derivatives.

Full text of DOI:10.1016/j.crci.2019.03.001

C. R. Chimie xxx (xxxx) xxx
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Preliminary communication/Communication
Access to NH-aziridine-2-carboxamides through Davidsen
acylimidodicarbonate activation
a
a
a, b, *
ꢁ
ꢁ
ꢀ
Jekaterına Ivanova , Boriss Strumfs , Raivis Zalubovskis
a Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
b Institute of Technology of Organic Chemistry, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Riga, Latvia
a r t i c l e i n f o
a b s t r a c t
Article history:
Acylimidodicarbonates obtained from aziridine-2-carboxamides through Davidsen bis-Boc
activation react with amine nucleophiles under mild conditions to form tertiary aziridine-
2-carboxylic acid amides. NH aziridine-2-carboxylic acid amides were obtained by
hydrogenolythic deprotection of N-Cbz derivatives.
Received 22 January 2019
Accepted 12 March 2019
Available online xxxx
© 2019 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Keywords:
Aziridine-2-carboxamides
Aziridines
Acylimidodicarbonates
Davidsen activation
Nucleophiles
Onlya small number of activation methods of aziridine-2-
carboxylic acid derivatives for ester and amide bound for-
mation are known in the literature. Some examples of N, N0 -
dicyclohexylcarbodiimide (DCC) [4e6], 1-ethyl-3-(3-dime-
thylaminopropyl)carbodiimide (EDC) [7] and Castro reagent
[8] activation have been reported. Other methods include
alkylation of metal aziridine-2-carboxylates [9], using an-
hydride [10], mixed anhydride [11,12] and in case of aziridine
2,2-dicarboxylic diesters, chloroanhydride activation have
been shown [13e15]. Some examples of solid phase peptide
synthesis have also been demonstrated [16,17]. These
methods are limited only to aziridine substrates with free
carboxyl or carboxylate salt functionality. Promising method
of AlMe3emediated aziridine-2-carboxylic acid ester ami-
nolysis was reported [18]. However, that method gave only
N-trityleprotected aziridine-2-carboxamides.
1. Introduction
Finding of novel potential anticancer drugs, as well as
development of efficient methods for their synthesis and
preparation of appropriate building blocks, is one of the most
challenging problems in medical chemistry. Because of the
electrophilic nature of the aziridine ring, derivatives of azir-
idine-2-carboxylicacidareinterestingsyntheticsubstratesfor
creating various amino acids, alkanolamines and heterocyclic
compounds [1]. Some derivatives of aziridine-2-carboxylic
acid, namely, imexon, azimexon [2] and leakadine [3] have
shown anticancer immunomodulatory activity themselves
and were developed as anticancer drug candidates.
Here, we report a convenient route for facile synthesis of
various aziridine-2-carboxamides using Davidsen bis-Boc
activation methodology [19].
2. Materials and methods
* Corresponding author. Latvian Institute of Organic Synthesis, Aiz-
The 1H NMR spectra were recorded using a Varian
Mercury 200 (200 MHz) and using Varian Mercury plus 400
kraukles 21, Riga, LV-1006, Latvia
ꢁ
E-mail address: raivis@osi.lv (R. Zalubovskis).
https://doi.org/10.1016/j.crci.2019.03.001
1631-0748/© 2019 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001

2
J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
Table 1
(400 MHz) spectrometers, TMS or CDCl3 remaining signal
7.26 ppm, solvent CDCl3) was used as an internal stan-
dard. The 13C NMR spectra were recorded using Varian
Mercury plus 400 spectrometers. CDCl3 remaining signal (
Reaction conditions and yields of intermediate amides 4.
(
d
No. Product 4
Reaction time
(h)
Yield
(%)
d
77.16 ppm) was used as an internal standard. High-
resolution mass spectrometry (HRMS) was measured
using a Waters Synapt G2-Si mass spectrometer. Melting
points were determined on a Gallenkamp heating stage
and are uncorrected. Thin-layer chromatography was car-
ried out using DC Alufolien plates of Kieselgel 60. Column
chromatography was carried out on silica gel (Merck),
0.023e0.070 mm, pore diameter ca. 6 nm. All solvents were
purified by standard procedures. Starting materials were
synthesized according to the known methods [19] for
compounds 3 and [20] 2 described in Section 5. General
procedures for compounds 4 and 6 are also described in
Section 5.
1
2
72
72
43
91
2
3
4
1.5
2
3. Results and discussion
Using aziridine-2-carboxamide (leakadine) (1) [3] as a
starting material protected and activated substrate 2 was
synthesized first by N-acylation of amide 1 with benzyl
chloroformate (Cbz-chloride) and second by reaction of
protected amide 2 with 2 equiv of Boc-anhydride under
DMAP-catalysed conditions (Scheme 1).
2
Activated aziridine 3 is isolable and stable at room
temperature.
Bis-Boceactivated amide 3 in reaction with a series of
primary (Table 1, entries 5e10) and secondary (Table 1,
entries 1e4) amines as well as anilines (Table 1, entries
11e15) gave amides 4aeo mostly in good yields (Scheme
2). The main withdraw is formation of bis-Boc-amine 5 as
a byproduct, therefore purification by chromatography is
required. It was observed that Cbz-protected compounds 4
often exhibited rather low stability by storing at room
temperature. That might be explained by electron
5
6
7
1.5
57
85
62
4
2.5
8
5
66
Scheme 1. Synthesis of acylimidodicarbonate 3.
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001

J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
3
Table 1 (continued )
No. Product 4
Reaction time
(h)
Yield
(%)
9
2
38
Scheme 2. Synthesis of amides 4 and 6.
10
3
7
90
Table 2
Reaction conditions and yields of deprotected aziridines 6.
No. Product 6
Reaction time
(h)
Yield
(%)
11
55
1
2
85
2
3
1.5
84
78
12
13
14
4
86
51
62
3
3
4
5
2
2
32
51
12
15
12
57
6
7
2
75
90
1.5
deficiency in aziridine. Therefore, aziridines
deprotected shortly after purification.
4 were
Deprotection of
4 was performed by palladium-
(continued on next page)
catalysed hydrogenation at atmospheric pressure at room
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001

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J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
Table 2 (continued)
No. Product 6
4. Conclusions
Reaction time
(h)
Yield
(%)
We have demonstrated
a convenient synthesis of
substituted amides of aziridine-2-carboxylic acid.
Activated acylimidodicarbonate obtained from azir-
idine-2-carboxamide reacts with various amines as nucle-
ophiles to form secondary and tertiary aziridine-2-
carboxylic acid amides. Hydrogenolythic deprotection of
obtained Cbz-protected compounds leads to corresponding
NH-aziridines. Reactions undergo at mild conditions and
are regioselective. No nucleophilic ring opening of azir-
idines is observed.
8
3
96
100
92
9
1.5
1.5
5. Experimental section
5.1. Synthesis of starting materials
10
5.1.1. Benzyl-2-(aminocarbonyl)aziridine-1-carboxylate (2)
11
12
1
2
83
75
Compound 1 (10.00 g, 0.12 mol) was dissolved in satu-
rated NaHCO3 (125 mL), EtOAc (125 mL) was added and
then CbzCl (16.49 mL, 0.12 mol) was added slowly. Reaction
mixture (RM) was stirred at room temperature for 3 days. It
was extracted with EtOAc (2 ꢀ 100 mL) and washed with
water. Organic phase was dried over Na2SO4, filtered and
evaporated. The product was obtained as a white crystal-
line solid (22.70 g, 89%), mp 92e93 ꢁC.
1H NMR (CDCl3, 200 MHz),
d
, ppm: 2.40 (1H, dd, J ¼ 0.6, J
13
2
74
¼ 3.3 Hz), 2.57 (1H, d, J ¼ 6.6 Hz), 3.04 (1H, dd, J ¼ 3.3, J ¼
6.6 Hz), 5.15 (2H, m), 5.77 (1H, br s), 6.17 (1H, br s),
7.20e7.45 (5H, m) [20].
LC-MS (ESI, m/z): [M þ Na]þ 243.
5.1.2. Benzyl-2-{[bis(tert-butoxycarbonyl)amino]carbonyl}
aziridine-1-carboxylate (3)
14
15
2
2
81
83
Benzyl-2-(aminocarbonyl)aziridine-1-carboxylate (2)
(3.00 g, 13.62 mmol) was suspended in dry DCM (30 mL),
DMAP (170 mg, 1.36 mmol) was added, RM was cooled to
0
ꢁC and Boc2O (5.95 g, 27.24 mmol) solution in dry DCM
(10 mL) was added slowly. RM was stirred at room tem-
perature until benzyl-2-(aminocarbonyl)aziridine-1-
carboxylate was completely dissolved (~30 min), filtered
through silica and evaporated. Product was purified by
column chromatography on silica gel, eluent ether/EtOAc
(4:1). Note: evaporation has to be done in vacuum with
temperature in short (1.5e3 h). The results are summarized
in Table 2. It is worth to notice that low hydrogen pressure
used in the reaction allows selective removal of the Cbz-
protecting group providing benzyl amides in good to high
yields (entries 2, 7e10).
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
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J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
5
heating at less than 30 ꢁC; purification has to be done
immediately after evaporation. The product was obtained
as a colourless oil (4.7 g, 82%).
purified by column chromatography on silica gel, eluent
petroleum ether/EtOAc (1:1). The product was obtained as
a colourless oil (443 mg, 72%).
1H NMR (CDCl3, 400 MHz),
d, ppm: 1.52 (18H, s),
1H NMR (CDCl3, 200 MHz), mixture of two rotamers,
d,
2.53e2.63 (2H, m), 4.05e4.12 (1H, m), 5.14 (2H, m),
7.30e7.40 (5H, m).
ppm: 2.35e2.48 (1H, m), 2.73e2.78 (1H, m), 2.94 (1.5H, s),
3.11 (1.5H, s), 3.23e3.29 (0.5H, m), 3.31e3.38 (0.5H, m),
4.57 (1H, s), 4.65 and 4.81 (1H, AB, J ¼ 17.0 Hz), 5.11 (1H, s),
5.11 and 5.17 (1H, AB, J ¼ 12.2 Hz), 7.12e7.40 (10H, m).
HRMS (ESI, m/z): [M þ H]þ Calcd C19H21N2O3: 325.1552.
Found: 325.1544.
13C NMR (D2O, 100 MHz),
d, ppm: 27.6, 28.0, 32.7, 36.1,
68.6, 81.9, 85.5, 128.4, 128.5, 135.4, 149.0, 161.0, 168.4.
HRMS (ESI, m/z): [M þ H]þ Calcd C21H29N2O7: 421.1975.
Found: 421.1968.
5.2. Amides 4aeo
5.2.4. Benzyl-2-(piperidin-1-ylcarbonyl)aziridine-1-
carboxylate (4c)
5.2.1. General procedure
Benzyl-2-{[bis(tert-butoxycarbonyl)amino]carbonyl}
aziridine-1-carboxylate (3) (1.00 g, 2.38 mmol) was dis-
solved in dry DCM (5 mL) and corresponding amino de-
rivative (2.38 mmol) was added. RM was stirred at room
temperature for 1.5e12 h and then evaporated. The product
was purified by column chromatography on silica gel,
eluent petroleum ether/EtOAc.
5.2.2. Benzyl-2-[(diethylamino)carbonyl]aziridine-1-
carboxylate (4a)
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(0.66 g,1.57 mmol) and piperidine (0.14 mL,1.41 mmol). RM
was stirred for 2 h. The product was purified by column
chromatography on silica gel, eluent petroleum ether/
EtOAc (1:1). The product was obtained as a colourless oil
(196 mg, 43%).
1H NMR (CDCl3, 200 MHz),
d, ppm: 1.40e1.65 (6H, m),
2.35e2.41 (1H, m), 2.66e2.71 (1H, m), 3.23e3.31 (1H, m),
3.34e3.76 (4H, m), 5.11 (2H, s), 7.32 (5H, s).
HRMS (ESI, m/z): [M þ H]þ Calcd C16H21N2O3: 289.1552.
Found: 289.1547.
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(1.19 g, 2.83 mmol) and diethylamine (0.26 mL, 2.55 mmol).
RM was stirred for 2 h. The product was purified by column
chromatography on silica gel, eluent petroleum ether/
EtOAc (1:1). The product was obtained as white crystalline
solid (562 mg, 72%).
5.2.5. Benzyl-2-(morpholin-4-yl)carbonyl]aziridine-1-
carboxylate (4d)
1H NMR (CDCl3, 200 MHz),
d
, ppm: 1.10 (3H, t, J ¼ 7.1 Hz),
1.23 (3H, t, J ¼ 7.1 Hz), 2.37e2.44 (1H, m), 2.70e2.76 (1H,
m), 3.20e3.27 (1H, m), 3.38 (2H, q, J ¼ 7.2 Hz), 3.40 (2H, m),
5.13 (2H, m), 7.35 (5H, m).
HRMS (ESI, m/z): [M þ H]þ Calcd C15H21N2O3: 277.1552.
Found: 277.1541.
5.2.3. Benzyl-2-{[benzyl(methyl)amino]carbonyl}aziridine-1-
carboxylate (4b)
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(1.00 g, 2.38 mmol) and morpholine (0.21 mL, 2.38 mmol).
RM was stirred for 2 h. The product was purified by column
chromatography on silica gel, eluent petroleum ether/
EtOAc (1:1). The product was obtained as a colourless oil
(630 mg, 91%).
1H NMR 2,45 (1H, d, J ¼ 5.6 Hz), 2.75 (1H, d, J ¼ 3.3 Hz),
3.24 (1H, dd, J ¼ 3.3 Hz, J ¼ 5.6 Hz), 3.44e3.53 (1H, m),
3.54e3.74 (6H, m), 3.77e3.87 (1H, m), 5.12 and 5.14 (AB,
2H, J ¼ 12.2 Hz), 7.30e7.41 (5H, m).
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(0.80 g, 1.90 mmol) and N-methyl-N-benzylamine (0.22 mL,
1.71 mmol). RM was stirred for 1.5 h. The product was
HRMS (ESI, m/z): [M þ H]þ Calcd C15H19N2O4: 291.1345.
Found: 291.1339.
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
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J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
5.2.6. Benzyl-2-[(isopropylamino)carbonyl]aziridine-1-
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate (3)
carboxylate (4e)
(0.70 g, 1.67 mmol) and benzylamine (0.17 mL, 1.51 mmol).
RM was stirred for 2.5 h. The product was purified by col-
umn chromatography on silica gel, eluent petroleum ether/
EtOAc (1:1). The product was obtained as a colourless oil
(320 mg, 62%).
1H NMR (CDCl3, 200 MHz),
d, ppm: 2.34e2.38 (1H, m),
2.46 (1H, dt, J ¼ 0.8, J ¼ 6.3 Hz), 3.07 (1H, dq, J ¼ 0.8, J ¼
3.4 Hz), 4.38 (2H, m), 5.09 and 5.12 (2H, AB, J ¼ 12.2 Hz),
7.16e7.37 (10H, m).
This is obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
HRMS (ESI, m/z): [M þ H]þ Calcd C18H19N2O3: 311.1396.
Found: 311.1390.
(0.91 g, 2.15 mmol) and isopropylamine (0.17 mL,
1.94 mmol). RM was stirred for 1.5 h. The product was
purified by column chromatography on silica gel, eluent
petroleum ether/EtOAc (1:1). The product was obtained as
a colourless oil (311 mg, 57%).
5.2.9. Benzyl-2-{[(3-methylbenzyl)amino]carbonyl}aziridine-
1-carboxylate (4h)
1H NMR (CDCl3, 200 MHz),
d
, ppm: 1.10 (3H, d, J ¼
6.6 Hz), 1.16 (3H, d, J ¼ 6.6 Hz), 2.28e2.32 (1H, m),
2.51e2.56 (1H, m), 3.02 (1H, dd, J ¼ 3.3, J ¼ 6.6 Hz),
3.90e4.12 (1H, m), 5.12 and 5.18 (2H, AB, J ¼ 12.1 Hz), 7.36
(5H, s).
HRMS (ESI, m/z): [M þ H]þ Calcd C14H19N2O3: 263.1396.
Found: 263.1392.
This was obtained from benzyl-2-{[bis(tert-butox-
5.2.7. Benzyl-2-[(pentylamino)carbonyl]aziridine-1-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
carboxylate (4f)
(1.00 g, 2.38 mmol) and 3-methylbenzylamine (0.27 mL,
2.14 mmol). RM was stirred for 5 h. The product was pu-
rified by column chromatography on silica gel, eluent pe-
troleum ether/EtOAc (1:1). The product was obtained as
colourless oil (505 mg, 66%).
1H NMR (CDCl3, 200 MHz),
d, ppm: 2.33 (3H, s), 2.36 (1H,
d, J ¼ 3.3 Hz), 2.57 (1H, d, J ¼ 6.6 Hz), 3.11 (1H, dd, J ¼ 3.3, J ¼
6.6 Hz), 4.38 (2H, m), 5.14 (2H, m), 6.97e7.23 (4H, m), 7.36
(5H, s).
This was obtained from benzyl-2-{[bis(tert-butox-
HRMS (ESI, m/z): [M þ H]þ Calcd C19H21N2O3: 325.1552.
Found: 325.1547.
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(1.04 g, 2.47 mmol) and n-pentylamine (0.26 mL,
2.23 mmol). RM was stirred for 4 h. The product was pu-
rified by column chromatography on silica gel, eluent pe-
troleum ether/EtOAc (1:1). The product was obtained as a
colourless oil (613 mg, 85%).
5.2.10. Benzyl-2-{[(2-methylbenzyl)amino]carbonyl}aziridine-
1-carboxylate (4i)
1H NMR (CDCl3, 200 MHz),
d, ppm: 0.83e0.93 (3H, m),
1.26e1.35 (4H, m), 1.40e1.54 (2H, m), 2.32 (1H, d, J ¼
3.3 Hz), 2.56 (1H, d, J ¼ 6.7 Hz), 3.05 (1H, dd, J ¼ 3.3 un
6.7 Hz), 3.22 (2H, m), 5.13 and 5.17 (2H, AB, J ¼ 12.1 Hz), 7.37
(5H, s).
HRMS (ESI, m/z): [M þ H]þ Calcd C16H23N2O3: 291.1709.
Found: 291.1713.
This was obtained from benzyl-2-{[bis(tert-butox-
5.2.8. Benzyl-2-[(benzylamino)carbonyl]aziridine-1-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
carboxylate (4g)
(0.60 g, 1.43 mmol) and 2-methylbenzylamine (0.16 mL,
1.29 mmol). RM was stirred for 2 h. The product was pu-
rified by column chromatography on silica gel, eluent pe-
troleum ether/EtOAc (2:1). The product was obtained as a
colourless oil (177 mg, 38%).
1H NMR (CDCl3, 200 MHz),
d, ppm: 2.28 (3H, s),
2.32e2.37 (1H, m), 2.55e2.61 (1H, m), 3.11 (1H, dd, J ¼ 3.4, J
¼ 6.7 Hz), 4.39e4.45 (2H, m), 5.14 (2H, m), 7.14e7.21 (4H,
m), 7.34e7.39 (5H, m).
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001

J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
7
HRMS (ESI, m/z): [M þ H]þ Calcd C19H21N2O3: 325.1552.
5.2.13. Benzyl-2-{[4-(trifluoromethyl)phenyl]carbamoyl}
aziridine-1-carboxylate (4l)
Found: 325.1551.
5.2.11. Benzyl-2-({[2-(trifluoromethyl)benzyl]amino}carbonyl)
aziridine-1-carboxylate (4j)
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate (3)
This was obtained from benzyl-2-{[bis(tert-butox-
(1.08 g, 2.57 mmol) and 4-trifluoromethylaniline (0.32 g,
2.57 mmol). RM was stirred for 4 h. The product was pu-
rified by column chromatography on silica gel, eluent pe-
troleum ether/EtOAc (2:1). The product was obtained as a
colourless oil (510 mg, 86%).
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(1.00 g, 2.38 mmol) and 2-trifluoromethylbenzylamine
(0.30 mL, 2.14 mmol). RM was stirred for 3 h. The
product was purified by column chromatography
on silica gel, eluent petroleum ether/EtOAc (2:1).
The product was obtained as a colourless oil (581 mg,
90%).
1H NMR (CDCl3, 400 MHz),
d
, ppm: 2.53 (1H, d, J ¼
3.4 Hz), 2.64 (1H, d, J ¼ 6.4 Hz), 3.26 (1H, dd, J ¼ 3.4, J ¼
6.4 Hz), 5.19 and 5.21 (2H, AB, J ¼ 12.1 Hz), 7.34e7.40 (5H,
m), 7.51 (2H, d, J ¼ 8.6 Hz), 7.61 (2H, d, J ¼ 8.6 Hz), 8.53 (1H,
br s).
1H NMR (CDCl3, 200 MHz),
d, ppm: 2.30e2.36 (1H, m),
2.57 (1H, dd, J ¼ 1.5, J ¼ 6.7 Hz), 3.06e3.14 (1H, m), 4.60 (2H,
m), 5.13 (2H, m), 7.29e7.54 (8H, m), 7.60e7.69 (1H, m).
HRMS (ESI, m/z): [M
365.1113. Found: 365.1109.
þ
H]þ Calcd C18H16F3N2O3:
HRMS (ESI, m/z): [M
379.1270. Found: 379.1266.
þ
H]þ Calcd C19H18F3N2O3:
5.2.14. Benzyl-2-[(4-methoxyphenyl)carbamoyl]aziridine-1-
carboxylate (4m)
5.2.12. Benzyl-2-[(4-chlorophenyl)carbamoyl]aziridine-1-
carboxylate (4k)
This was obtained from benzyl-2-{[bis(tert-butox-
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(0.97 g, 2.31 mmol) and 4-methoxyaniline (0.29 g,
2.31 mmol). RM was stirred for 3 h. The product was pu-
rified by column chromatography on silica gel, eluent pe-
troleum ether/EtOAc (1:1). The product was obtained as a
colourless oil (382 mg, 51%).
(0.90 g, 2.15 mmol) and 4-tert-butylaniline (0.34 mL,
2.15 mmol). RM was stirred for 7 h. The product was pu-
rified by column chromatography on silica gel, eluent pe-
troleum ether/EtOAc (2:1). The product was obtained as a
colourless oil (414 mg, 55%).
1H NMR (CDCl3, 400 MHz),
d, ppm: 2.44 (1H, d, J ¼
1H NMR (CDCl3, 400 MHz),
d, ppm: 1.30 (9H, s), 2.43 (1H,
3.4 Hz), 2.66 (1H, d, J ¼ 6.9 Hz), 3.18 (1H, dd, J ¼ 3.4, J ¼
6.9 Hz), 3.79 (3H, s), 5.15 and 5.20 (2H, AB, J ¼ 12.1 Hz), 6.86
(2H, d, J ¼ 9.0 Hz), 7.38 (5H, s), 7.42 (2H, d, J ¼ 9.0 Hz), 7.84
(1H, br s).
d, J ¼ 3.3 Hz), 2.66 (1H, d, J ¼ 6.8 Hz), 3.19 (1H, dd, J ¼ 3.3 Hz,
J ¼ 6.8 Hz), 5.17 and 5.20 (2H, AB, J ¼ 12.1 Hz), 7.34 (2H, d, J
¼ 8.6 Hz), 7.37 (5H, s), 7.43 (2H, d, J ¼ 8.6 Hz), 7.89 (1H, br s).
HRMS (ESI, m/z): [M þ H]þ Calcd C21H25N2O3: 353.1865.
Found: 353.1860.
HRMS (ESI, m/z): [M þ H]þ Calcd C18H19N2O4: 327.1345.
Found: 327.1339.
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001

8
J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
5.2.15. Benzyl-2-[(3,5-dimethylphenyl)carbamoyl]aziridine-1-
purified by column chromatography on silica gel, eluent
carboxylate (4n)
DCM/MeOH (9:1).
5.3.2. N,N-Diethylaziridine-2-carboxamide (6a)
This was obtained from benzyl-2-[(diethylamino)
carbonyl]aziridine-1-carboxylate (4a) (0.56 g, 2.03 mmol)
and Pd/C (22 mg, 0.20 mmol). RM was stirred for 2 h. The
product was obtained as yellow liquid (245 mg, 85%).
This was obtained from benzyl-2-{[bis(tert-butox-
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(1.00 g, 2.30 mmol) and 3,5-dimethylaniline (0.29 mL,
2.38 mmol). RM was stirred for 12 h. The product was
purified by column chromatography on silica gel, eluent
petroleum ether/EtOAc (2:1). The product was obtained as
a colourless oil (477 mg, 62%).
1H NMR (D2O, 400 MHz),
d
, ppm: 1.12 (3H, t, J ¼ 7.2 Hz),
1.27 (3H, t, J ¼ 7.2 Hz), 1.87 (1H, d, J ¼ 3.4 Hz),1.94 (1H, d, J ¼
6.1 Hz), 2.93 (1H, dd, J ¼ 3.4, J ¼ 6.1 Hz), 3.34e3.48 (2H, m),
3.66e3.71 (2H, m).
13C NMR (D2O, 100 MHz),
41.6, 42.2, 170.8.
d
, ppm: 12.0, 13.4, 25.3, 27.6,
1H NMR (CDCl3, 400 MHz),
d, ppm: 2.28 (6H, s), 2.42 (1H,
d, J ¼ 3.5 Hz), 2.66 (1H, d, J ¼ 6.9 Hz), 3.17 (1H, dd, J ¼ 3.5 Hz,
J ¼ 6.9 Hz), 5.16 and 5.20 (2H, AB, J ¼ 12.1 Hz), 6.77 (1H, s),
7.15 (2H, s), 7.37 (5H, s), 7.86 (1H, br s).
HRMS (ESI, m/z): [M
165.1004. Found: 165.1007.
þ
Na]þ Calcd C7H14N2ONa:
HRMS (ESI, m/z): [M þ H]þ Calcd C19H21N2O3: 325.1552.
Found: 325.1551.
5.3.3. N-Benzyl-N-methylaziridine-2-carboxamide (6b)
5.2.16. Benzyl-2-[(2,4-dimethylphenyl)carbamoyl]aziridine-1-
carboxylate (4o)
This was obtained from benzyl-2-{[benzyl(methyl)
amino]carbonyl}aziridine-1-carboxylate (4b) (440 mg,
1.36 mmol) and Pd/C (15 mg, 0.14 mmol). RM was stirred
for 1.5 h. The product was obtained as a colourless oil (yield
217 mg, 84%).
1H NMR (CD3OD, 400 MHz), mixture of two rotamers,
d,
This was obtained from benzyl-2-{[bis(tert-butox-
ppm: 1.77e1.92 (2H, m), 2.87e2.95 (1H, m), 2.98 (1.5H, s),
3.13 (1.5H, s), 4.60 and 4.65 (1H, AB, J ¼ 14.8 Hz), 4.76e4.83
(1H, m), 7.22e7.42 (5H, m).
ycarbonyl)amino]carbonyl}aziridine-1-carboxylate
(3)
(1.06 g, 2.52 mmol), 2,4-dimethylaniline (0.29 g,
2.38 mmol) and DMAP (0.03 g, 0.25 mmol). RM was stirred
for 12 h. The product was purified by column chromatog-
raphy on silica gel, eluent petroleum ether/EtOAc (1:1). The
product was obtained as a colourless oil (465 mg, 57%).
13C NMR (CD3OD, 100 MHz), mixture of two rotamers,
d,
ppm: 26.7, 27.0, 28.3, 28.7, 34.6, 35.0, 52.4, 53.6, 127.8,
128.6, 128.8, 128.9, 129.7, 130.0, 138.0, 138.1, 172.3, 172.5.
HRMS (ESI, m/z): [M þ H]þ Calcd C11H15N2O: 191.1184.
Found: 191.1190.
1H NMR (CDCl3, 400 MHz),
d, ppm: 2.17 (3H, s), 2.28
(3H,s), 2.46 (1H, d, J ¼ 3.4 Hz), 2.69 (1H, d, J ¼ 6.8 Hz), 3.22
(1H, dd, J ¼ 3.4 Hz, J ¼ 6.8 Hz), 5.18 and 5.19 (2H, AB, J ¼
12.1 Hz), 6.97e7.03 (2H, m), 7.37 (5H, s), 7.68 (1H, d, J ¼
8.1 Hz), 7.84 (1H, br s).
5.3.4. 1-[(Aziridin-2-yl)carbonyl]piperidine (6c)
HRMS (ESI, m/z): [M þ H]þ Calcd C19H21N2O3: 325.1552.
Found: 325.1546.
5.3. Amides 6aeo
5.3.1. General procedure for elimination of Cbz group
Benzyl-2-substituted aziridine-1-carboxylate 4aeo was
dissolved in MeOH and Pd/C (10 mol%) was added. RM was
stirred under hydrogen (p ¼ 1 atm) 1.5e3 h. RM was
filtered through Celite and evaporated. The products were
This was obtained from benzyl-2-(piperidin-1-
ylcarbonyl]aziridine-1-carboxylate
(4c)
(0.19
g,
0.66 mmol) and Pd/C (7 mg, 0.07 mmol). RM was stirred for
3 h. The product was obtained as a yellow oil (80 mg, 78%).
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
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9
1H NMR (CD3OD, 400 MHz),
d
, ppm: 1.53e1.60 (3H, m),
and Pd/C (22 mg, 0.21 mmol). RM was stirred for 2 h. The
product was obtained as a yellow liquid (246 mg, 75%).
1.68e1.74 (3H, m), 1.78 (1H, dd, J ¼ 1.4, J ¼ 3.4 Hz), 1.83 (1H,
d, J ¼ 5.8 Hz), 2.89 (1H, dd, J ¼ 3.4, J ¼ 5.8 Hz), 3.54e3.60
(2H, m), 3.66e3.71 (2H, m).
1H NMR (D2O, 400 MHz),
d, ppm: 0.85e0.91 (3H, m),
1.27e1.35 (4H, m), 1.49e1.57 (2H, m), 1.83e1.95 (2H, m),
2.56e2.62 (1H, m), 3.32 (2H, t, J ¼ 6.9 Hz).
13C NMR (CD3OD, 100 MHz),
26.2, 27.2, 43.5, 45.7, 168.7.
d, ppm: 24.0, 24.9, 25.2,
13C NMR (D2O, 100 MHz),
28.2, 29.6, 39.5, 172.5.
d, ppm: 13.2, 21.6, 27.1, 27.9,
HRMS (ESI, m/z): [M þ H]þ Calcd C8H15N2O: 155.1184.
Found: 155.1178.
HRMS (ESI, m/z): [M þ H]þ Calcd C8H17N2O: 157.1341.
Found 157.1336.
5.3.5. Aziridin-2-yl(morpholin-4-yl)methanone (6d)
5.3.8. N-Benzylaziridine-2-carboxamide (6g)
This was obtained from benzyl-2-(morpholin-4-yl)
carbonyl]aziridine-1-carboxylate (4d) (0.84 g, 2.88 mmol)
and Pd/C (31 mg, 0.29 mmol). RM was stirred for 2 h. Yield
145 mg, 32%.
This was obtained from benzyl-2-[(benzylamino)
carbonyl]aziridine-1-carboxylate (4g) (0.32 g, 1.02 mmol)
and Pd/C (11 mg, 0.10 mmol). RM was stirred for 1.5 h. Yield
161 mg, 90%.
1H NMR (CD3OD, 400 MHz),
d
, ppm: 1.82 (1H, dd, J ¼
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.68e1.98 (2H, m),
1.4 Hz, J ¼ 3.4 Hz), 1.83e1.89 (1H, m), 2.89 (1H, dd, J ¼
2.49e2.60 (1H, m), 4.41 (2H, s), 7.23e7.35 (5H, m).
3.4 Hz, J ¼ 5.6 Hz), 3.61e3.81 (8H, m).
13C NMR (CD3OD, 100 MHz),
128.4, 128.6, 129.6, 139.7, 172.6.
d, ppm: 26.0, 30.6, 44.4,
13C NMR (CD3OD, 100 MHz),
67.6, 67.8, 82.4, 170.7.
d, ppm: 28.4, 44.1, 46.6,
HRMS (ESI, m/z): [M þ H]þ Calcd C10H13N2O: 177.028.
HRMS (ESI, m/z): [M þ H]þ Calcd C7H13N2O2
Found: 177.1033.
157.0977. Found 157.0981.
5.3.9. N-(3-Methylbenzyl)aziridine-2-carboxamide (6h)
5.3.6. N-Isopropylaziridine-2-carboxamide (6e)
This was obtained from benzyl-2-{[(3-methylbenzyl)
amino]carbonyl}aziridine-1-carboxylate (4h) (0.51 g,
1.56 mmol) and Pd/C (17 mg, 0.16 mmol). RM was stirred
for 3 h. Yield 284 mg, 96%. Mp 58e59 ꢁC.
This was obtained from benzyl-2-[(isopropylamino)
carbonyl]aziridine-1-carboxylate (4e) (0.31 g, 1.19 mmol)
and Pd/C (13 mg, 0.12 mmol). RM was stirred for 2 h. The
product was obtained as a colourless oil (78 mg, 51%).
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.73e1.94 (2H, m),
1H NMR (D2O, 400 MHz),
d, ppm: 1.12e1.19 (6H, m),
2.32 (3H, s), 2.51e2.56 (1H, m), 4.37 (2H, s), 7.05e7.12 (3H,
m), 7.17e7.23 (1H, m).
1.84e1.93 (2H, m), 2.53e2.58 (1H, m), 3.90e4.01 (1H, m).
13C NMR (D2O, 100 MHz),
41.9, 171.4.
d
, ppm: 21.2, 21.3, 27.1, 29.7,
13C NMR (CD3OD, 100 MHz),
d, ppm: 21.4, 26.0, 30.6,
44.4, 125.7, 129.0, 129.3, 129.5, 139.4, 139.5, 172.6.
HRMS (ESI, m/z): [M þ H]þ Calcd C11H15N2O: 191.1184.
Found: 191.1179.
HRMS (ESI, m/z): [M
þ
Na]þ Calcd C6H12N2ONa:
151.0847. Found: 151.0841.
5.3.7. N-Pentylaziridine-2-carboxamide (6f)
5.3.10. N-(2-Methylbenzyl)aziridine-2-carboxamide (6i)
This was obtained from benzyl-2-[(pentylamino)
This was obtained from benzyl-2-{[(2-methylbenzyl)
carbonyl]aziridine-1-carboxylate (4f) (0.16 g, 2.10 mmol)
amino]carbonyl}aziridine-1-carboxylate (4i) (170 mg,
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
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10
J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
0.52 mmol) and Pd/C (6 mg, 0.05 mmol). RM was stirred for
5.3.13. N-[4-(Trifluoromethyl)phenyl]aziridine-2-carboxamide
(6l)
1.5 h. Yield 129 mg, 100%. Mp 78e79 ꢁC.
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.69e1.97 (2H, m),
2.32 (3H, s), 2.51e2.58 (1H, m), 4.42 (2H, s), 7.14e7.19 (3H,
m), 7.21e7.25 (1H, m).
13C NMR (CD3OD, 100 MHz),
d, ppm: 19.0, 26.0, 30.5,
42.7, 127.1, 128.6, 129.3, 131.4, 137.0, 137.4, 172.4.
HRMS (ESI, m/z): [M þ H]þ Calcd C11H15N2O: 191.1184.
Found: 191.1187.
5.3.11. N-[2-(Trifluoromethyl)benzyl]aziridine-2-carboxylate
(6j)
This was obtained from benzyl-2-{[4-(trifluoromethyl)
phenyl]carbamoyl}aziridine-1-carboxylate (4l) (0.50 g,
1.37 mmol) and Pd/C (24 mg, 0.22 mmol). RM was stirred
for 2 h. Yield 238 mg, 75%.
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.83e2.02 (2H, m),
2.67e2.73 (1H, m), 7.61 (2H, d, J ¼ 8.4 Hz), 7.80 (2H, d, J ¼
8.4 Hz).
13C NMR (CD3OD, 100 MHz),
d, ppm: 26.7, 31.2, 120.7,
125.7 (J ¼ 271 Hz), 126.8 (J ¼ 32.9 Hz), 127.1 (J ¼ 3.8 Hz),
143.1; 171.3.
HRMS (ESI, m/z): [M
231.0745. Found 231.0747.
þ
H]þ Calcd C10H10N2OF3:
This was obtained from benzyl-2-({[2-(trifluoromethyl)
benzyl]amino}carbonyl)aziridine-1-carboxylate
(4j)
5.3.14. N-(4-Methoxyphenyl)aziridine-2-carboxamide (6m)
(0.58 g, 1.52 mmol) and Pd/C (16 mg, 0.15 mmol). RM was
stirred for 1.5 h. The product obtained was a colourless oil
(Yield 341 mg, 92%). .
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.76e1.96 (2H, m),
2.56e2.63 (1H, m), 4.62 (2H, s), 7.43e7.48 (1H, m),
7.51e7.55 (1H, m), 7.58e7.64 (1H, m), 7.68e7.73 (1H, m).
13C NMR (CD3OD, 100 MHz),
d, ppm: 26.1, 30.5, 41.0,
124.6,126.0 (q, J ¼ 273 Hz),127.0 (q, J ¼ 5.7 Hz),128.8,130.6,
133.6, 137.8, 173.0.
HRMS (ESI, m/z): [M þ Na]þ Calcd C11H11F3N2ONa:
267.0721. Found: 267.0727.
This was obtained from benzyl 2-[(4-methoxyphenyl)
carbamoyl]aziridine-1-carboxylate
(4m)
(0.37
g,
1.13 mmol) and Pd/C (12 mg, 0.11 mmol). RM was stirred for
2 h. Yield 161 mg, 74%.
5.3.12. N-(4-tert-butylphenyl)aziridine-2-carboxamide (6k)
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.74e2.05 (2H, m),
2.60e2.69 (1H, m), 3.77 (3H, s), 6.85e6.90 (2H, m),
7.44e7.49 (2H, m).
13C NMR (CD3OD, 100 MHz),
115.0, 115.9, 122.9, 132.6, 158.1.
d, ppm: 26.3, 31.0, 55.9,
HRMS (ESI, m/z): [M þ H]þ Calcd C10H13N2O2: 193.0977.
Found 193.0975.
5.3.15. N-(3,5-Dimethylphenyl)aziridine-2-carboxamide (6n)
This was obtained from 2-[(tert-butylphenyl)carba-
moyl]aziridine-1-carboxylate (4k) (0.40 g, 1.14 mmol) and
Pd/C (12 mg, 0.11 mmol). RM was stirred for 1 h. Yield
207 mg, 83%.
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.31 (9H, s),
1.80e2.00 (2H, m), 2.63e2.69 (1H, m), 7.33e7.38 (2H, m),
7.46e7.51 (2H, m)
13C NMR (CD3OD,100 MHz),
d
, ppm: 26.4, 31.1, 31.8, 35.2,
This was obtained from benzyl 2-[(3,5-dimethylphenyl)
carbamoyl]aziridine-1-carboxylate (4n) (0.46 g, 1.42 mmol)
and Pd/C (23 mg, 0.14 mmol). RM was stirred for 2 h. Yield
81%, 218 mg.
120.9, 126.7, 136.9, 148.5, 170.7.
HRMS (ESI, m/z): [M þ H]þ Calcd C13H19N2O: 219.1497.
Found: 219.1499.
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001

J. Ivanova et al. / C. R. Chimie xxx (xxxx) xxx
11
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.83e1.89 (1H, m),
Appendix A. Supplementary data
1.91e1.97 (1H, m), 2.27 (6H, d, J ¼ 0.8 Hz), 2,65 (1H, dd, J ¼
3.2 Hz, J ¼ 5.7 Hz), 6.75e6.78(1H, m), 7.18e7.20 (2H, m).
Supplementary data to this article can be found online
at https://doi.org/10.1016/j.crci.2019.03.001.
13C NMR (CD3OD, 100 MHz),
118.9, 127.0, 139.3, 139.7, 170.7.
d, ppm: 21.5, 26.4, 31.1,
HRMS (ESI, m/z): [M þ H]þ Calcd C11H15N2O: 191.1184,
References
Found 191.1180.
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218e223.
5.3.16. N-(2,4-Dimethylphenyl)aziridine-2-carboxamide (6o)
[3] I.Y. Kalvinsh, E.B. Astapenok, US Patent US4686215, Appl. US06/
693,171, Aug. 11, (1987).
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Tetrahedron 43 (2002) 6461e6466.
This was obtained from benzyl 2-[(2,4-dimethylphenyl)
carbamoyl]aziridine-1-carboxylate (4o) (0.45 g, 1.39 mmol)
and Pd/C (15 mg, 0.14 mmol). RM was stirred for 2 h. Yield
218 mg, 83%.
[13] B.R. Henke, A.J. Kouklis, C.H. Heathcock, J. Org. Chem. 57 (1992)
7056e7066.
1H NMR (CD3OD, 400 MHz),
d, ppm: 1.79e2.03 (2H, m),
2.21 (3H, s), 2.29 (3H, s), 2.73 (1H, dd, J ¼ 3.1 Hz, J ¼ 5.7 Hz),
6.97e7.02 (1H, m), 7.04e7.07 (1H, m), 7.21e7.30 (1H, m).
13C NMR (CD3OD, 100 MHz), 17.9, 21.0, 26.4, 30.8, 126.4,
127.9, 132.2, 133.9, 137.3, 171.7.
[14] D.A. Griffith, C.H. Heathcock, Tetrahedron Lett. 36 (1995)
2381e2384.
[15] G. Cardillo, S. Fabbroni, L. Gentilucci, M. Gianotti, R. Perciaccante,
S. Selva, A. Tolomelli, Tetrahedron Asymmetry 13 (2002) 1411e1415.
[16] H. Konno, K. Kubo, H. Makabe, E. Toshiro, N. Hinoda, K. Nosaka,
K. Akaji, Tetrahedron 63 (2007) 9502e9513.
HRMS (ESI, m/z): [M þ H]þ Calcd C11H15N2O: 191.1184.
Found 191.1176.
[17] D.P. Galoni, N.D. Ide, W.A. van der Donk, D.Y. Gin, J. Am. Chem. Soc.
127 (2005) 7359e7369.
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5482e5485.
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Acknowledgements
This work was supported by ERDF project no. 1.1.1.2/
VIAA/1/16/242.
Please cite this article as: J. Ivanova et al., Access to NH-aziridine-2-carboxamides through Davidsen acylimidodicarbonate
activation, Comptes Rendus Chimie, https://doi.org/10.1016/j.crci.2019.03.001