Thermal Ring Expansion of 2-Sulfonylimidoyl-1-phthalimidoaziridines into N-Sulfonylimidazoles

A Journal of

Accepted Article

Title: Thermal Ring Expansion of 2-Sulfonylimidoyl-1-

phthalimidoaziridines into N-Sulfonylimidazoles

Authors: Aleksandr Stukalov, Vitalii V. Suslonov, and Mikhail

Kuznetsov

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To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.201701806

Link to VoR: http://dx.doi.org/10.1002/ejoc.201701806

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10.1002/ejoc.201701806

European Journal of Organic Chemistry

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Thermal Ring Expansion of 2-Sulfonylimidoyl-1-

phthalimidoaziridines into N-Sulfonylimidazoles

Aleksandr Stukalov,^[a]Vitalii V. Suslonov^[b]and Mikhail A. Kuznetsov ^*[a]

Abstract: The oxidative phthalimidoaziridination of conjugated

unsaturated N-sulfonylimines leads in most cases to disubstituted,

trisubstituted and spirofused imidoylaziridines in synthetically useful

yields typically above 70%. The latter are thermally transformed to

disubstituted, trisubstituted and condensed N-sulfonylimidazoles.

Interestingly, this ring expansion is accompanied by the

intramolecular 1,3-sulfonyl shift from one nitrogen atom to another.

Introduction

Aziridines are widely utilized in organic synthesis since

their ring strain drives a plethora of ring opening reactions.¹

A

typical example is the transformation of aziridines into nitrogen-

containing five-membered heterocycles, most often via a 1,3-

dipolar cycloaddition of various dipolarophiles with azomethine

ylides that form thermally from aziridines.²Intramolecular

versions of this pathway are less common and occur when the

unsaturated substituent is directly linked to the aziridine ring, for

example, such as in a vinylaziridine-pyrroline rearrangement³

and the ring expansion of N-acylaziridines into oxazolines.⁴

Previously, we have demonstrated that readily available 2-acyl-

and 2-azo-1-phthalimimidoaziridines transform into oxazoles⁵

and 2H-1,2,3-triazoles⁶in good yields, accompanied by a loss of

the phthalimide fragment. We were therefore interested if

structurally similar transformations of N-phthalimidoaziridines

with unsaturated substituents could yield other aromatic nitrogen

heterocycles, in particular, imidazoles from 2-imidoylaziridines.

There is a single example of such a ring expansion of 2-imidoyl-

1-sulfonyl aziridines in the literature, but it is limited to the

preparation of N-alkyl-2,5-diaryl-4-chloroimidazoles⁷. Therefore

the objective of the current work is the investigation of

Scheme 1. Synthesis of oxazoles, 1,2- and 1,3-diazoles from 1-oxa- and 1-

azadienes

While aziridines generally form as by-products, acceptable

isolated yields of aziridines were obtained only for imines with

electron-deficient aryl substituents at the imine nitrogen atom

(Scheme 1). This change in chemoselectivity is due to the

suppressed nucleophilicity of the lone electron pair of the

nitrogen atom that otherwise competes with the C=C bond for

the nitrenoid leading to pyrazoles. Only if it becomes less

reactive than the double bond, the formation of imidoylaziridines

occurs.¹⁰For this reason we investigated the oxidative addition

of N-aminophthalimide to 1-azadienes with a strongly electron-

withdrawing sulfo group at the nitrogen atom and the thermal

thermolysis of

a

representative series of 2-imidoyl-1-

phthalimidoaziridines.

expansion

of

2-(N-sulfonylimidoyl)aziridines

into

N-

It should be noted that the synthesis of 2-imidoylaziridines

from the corresponding 2-acylaziridines is complicated by the

conversion of the former to oxazolines or oxazoles^5,8at high

temperatures; in addition, the aziridine ring easily opens up in

the presence of nucleophilic reagents and acids.⁹As such, our

preferred synthetic strategy relied on aziridination of appropriate

α,β-unsaturated imines.

sulfonylimidazoles. Since imidazole derivatives possess diverse

biological activity^11-14and are also used as precursors to N-

heterocyclic carbene (NHC) ligands¹⁵and ionic liquids¹⁶, we

studied this intriguing transformation in details and report our

results herein.

However, we have shown recently that the oxidative

phthalimidoaziridination of chalcone arylimines (1,2,4-triaryl-1-

azabuta-1,3-dienes) gives 1,3,5-triarylpyrazoles in good yields

instead of the corresponding imidoyl aziridines.¹⁰

Results and Discussion

The starting N-sulfonylimines 2 were obtained in good yields

from readily available unsaturated ketones 1 with the (E)-

configuration of the double bond and arylsulfonamides in the

presence of TiCl₄/Et₃N.¹⁷Generally, isomerization of the C=C

bond was not observed under the reaction conditions, however,

with 2l,l' and 2m,m' mixtures of (E/Z)-stereoisomers about this

bond were obtained and separated by column chromatography.

Moreover, according to the X-ray diffraction data, imines 2l and

2l' have different configurations about the C=N bonds (Figure 1).

[a]

[b]

Institute of Chemistry, Saint Petersburg State University,

Universitetskii pr. 26, 198504 Saint Petersburg, Russia.

E-mail: m.kuznetsov@spbu.ru

http://www.chem.spbu.ru/org/592-kuznetsov_scigroup

Center for X-ray Diffraction Studies, Saint Petersburg State

University, Universitetskii pr. 26, 198504 Saint Petersburg, Russia.

Supporting information for this article is available on the WWW

under http://dx.doi.org/

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European Journal of Organic Chemistry

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Table 1. Preparation of α,β-unsaturated N-sulfonylimines 2.

Table 2. Synthesis of 2-imidoyl-1-phthalimidoaziridines 3.

2l'

2l

3f

3m

3o

Figure 1. X-ray crystal structures of imines 2l and 2l’.

Figure 2. X-ray crystal structures of aziridines 3f, 3m and 3o.

However, when the temperature is lowered down to –20°C,

both double bond protons of 2c become clear doublets with

Typically, N-sulfonylimines have a low barrier of (E/Z)-

isomerization about the C=N bond,¹⁸which is manifested in the

broadening of some signals in their NMR spectra at room

3

vicinal coupling constants J = 16.1 Hz at δ 8.10 (H^α) and 7.10

(H^β) ppm. Given the high barrier for (E/Z)-isomerization about

the C=N bond in 2k due to the steric hindrance of the tert-butyl

substituent and no broaden signals in its ¹H and ¹³C NMR

spectra at room temperature, it is likely that 2k has a stable (E)-

configuration of the C=N bond.

Next, 2-imidoylaziridines 3 with various substitution patterns

were synthesized (Table 2). Although strongly twisted imines

2l',m' do not engage in oxidative phthalimidoaziridination,

trisubstituted aziridines 3l,m were successfully prepared from

stereoisomers 2l,m. Aziridine 3k with a tert-butyl substituent was

obtained only in a 20% yield. That said, TLC analysis showed

substantial amounts of the starting material in the reaction

mixture and it was not possible to increase its conversion even

with more than two-fold excess of aziridinating reagents.

1

temperature. Room temperature H NMR spectra of imines 2l,m

with the (E)-configuration of the C=C bond feature signals of all

aromatic protons as one strongly broadened multiplet at δ 6.68-

8.08 ppm. Likewise, the ¹³C NMR spectra of 2l,m reveal that

several signals are broadened so strongly that they merge with

the baseline. Cooling the sample down to –20°C allows

1

resolving three sets of signals in H NMR spectra of 2l,m that

correspond to the three isomeric forms in 1:0.64:0.21 ratio. This

indicates that as the temperature decreases, not only

isomerization about the C=N bond, but also another dynamic

process, namely rotation around the single bond of the C=C–

C=N fragment slows down. While one could a priori expect four

sets of signals as each of the two stereoisomers about the C=N

bond could exist as s-cis- and s-trans- conformers, one of these

A successful selective phthalimidoaziridination of conjugated

olefins containing other unsaturated sites requires the s-cis

conformation of the C=C–C=X (X = C, O) fragment, and the

nitrenoid attack on the C=C bond occurs from the side of the

unsaturated substituent C=X.¹⁹In this case, stabilizing

secondary orbital interactions appear between the C=O bond of

the phthalimido group and the C=X bond of the unsaturated

substrate and this lowers the energy of the respective transition

state. The inertness of 2l',m' and the low reactivity of 2k could

be due to the large steric hindrance shutting down the

accessibility of the s-cis conformation of the C=C–C=N fragment

in which the C=C bond is blocked by an arylsulfonyl group.

forms is present below the NMR detection limit.

In contrast, sterically hindered imines 2l',m' with (Z)-

configurations of both C=C and C=N bonds feature at room

temperature only one set of signals with narrow lines, which

indicates the lack of dynamic processes at the NMR time scale.

¹H NMR spectra of disubstituted imines 2a-j at room

temperature reveal the signal of the H^αproton of the double

bond at δ 7.84-8.22 ppm as a strongly broadened multiplet,

although the H^βsignal at δ 7.01-7.17 (7.59 for 2j) ppm is a

3

doublet with vicinal coupling constants J = 16.0-16.2 Hz, which

indicates (E)-configuration of C=C bonds in these compounds.

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Table 3. Synthesis of N-sulfonylimidazoles 4.

Due to the slow inversion of the endocyclic nitrogen atom,

disubstituted aziridines 3a-j exist as a mixture of two invertomers

and their ratio varies from 0.14:1 to 0.44:1. The signals of

aziridine ring protons are found at δ 3.79-3.87 (H², 2.86 for 3j)

and 4.72-4.86 (H³, 4.63 for 3j) ppm for the main invertomer, and

at δ 5.62-6.10 (H², 5.65-5.77 for 3j) and 4.03-4.14 (H³, 4.11 for

3j) ppm for the minor one. Usually, the phthalimido substituent

deshields the syn-oriented proton, and the lone pair of the

endocyclic nitrogen atom, on the contrary, shields it.¹⁹Based on

these arguments we can conclude that the phthalimido

substituent and the H³proton (and hence the imidoyl group) are

syn-oriented in the main invertomers, and anti-oriented in the

minor ones.

At room temperature, there is a relatively fast isomerization

about the C=N bond in the anti-invertomer reflected in a strong

broadening (by almost 0.5 ppm) of the signal of the neighboring

aziridine H²proton; note that there is no signal broadening for

the spatially hindered syn-invertomer. However, at –20°C,

1

according to H NMR of 3d, the signal of the minor form at δ

H⁴of 5-alkyl-1-sulfonylimidazoles resonates at δ 6.26-6.46 ppm.

Fully substituted imidazoles 4l,m are obtained from aziridines

3l,m in good yields. At the same time, thermolysis of

spiroaziridine 3n leads to a mixture of isomers. While 3o yields

only 4o (44%) at 120 ° C in 12 h, 3n under the same conditions

gives merely 6% of imidazole 4n and, surprisingly, 51% of its

isomer 4n'. When heated to 150 °C, imidazole 4n was the sole

product (32% yield). Moreover, isolated 4n' was transformed into

4n at this temperature, but strong tarring of the reaction mixture

was observed. 2D NOESY used for the structural assignment of

condensed imidazoles reveals cross peaks between signals of

the tosyl group at δ 7.29, 7.34 ppm and methylene groups

connected to the imidazole ring at δ 4.01, 3.31 ppm for 4n,o.

There is also an NOE between the protons of the tosyl group (δ

7.33 ppm) and H⁴proton of the condensed phenyl ring (δ 8.26

ppm) for 4n'.

Overall, observed results can be explained by the initial

formation of expected imidazoles and a subsequent sulfonyl shift,

a process well-known in the literature.²³We speculate that steric

factors could be the driving force of this process since the

sulfonyl group migrates from the nitrogen atom sandwiched

between two bulky substituents to the less hindered position.

Note that for 4l,m this rearrangement is degenerate. Imidazoles

4' (except 4n') are labile under the reaction conditions and

immediately transform into more stable imidazoles 4.

To substantiate our assumptions regarding the migration of

the sulfonyl group, we have prepared tosylimine 2c-¹⁵N from the

¹⁵N-labeled oxime 5 and p-toluenesulfinyl chloride using a

known reaction,²⁴and then synthesized 3c-¹⁵N as described

above (Scheme 2). Thermolysis of 3c-¹⁵N yields imidazole 4c-

¹⁵N containing the tosyl group at the unlabeled nitrogen atom.

¹H-¹⁵N HMBC spectrum of unlabeled 4c features nitrogen atoms

at δ 207.6 (pyrrole-type nitrogen) and 271.6 (pyridine-type

nitrogen) ppm. There is only one signal at δ 271.6 ppm

corresponding to the pyridine-type nitrogen atom in the ¹⁵N NMR

spectrum of the labeled compound 4c-¹⁵N, i.e. tosyl substituent

is no longer attached to this nitrogen atom. In agreement with

this, ¹³C NMR spectrum of 4c-¹⁵N has signals of ipso-carbons of

both phenyl rings at δ 129.5 and 132.2 ppm coupled with the

5.90 (H²) is already a typical narrow doublet. The values of

vicinal coupling constants of ³J=4.6-4.8 Hz for the main

invertomers and 5.3-5.5 Hz for the minor ones correspond to the

trans-arrangement of the aziridine ring protons, consistent with

the well-known retention of the double bond configuration in

oxidative aminoaziridination reactions.²⁰This is also confirmed

by the X-ray diffraction analysis of 3f (Figure 2). The solid state

structure of 3f corresponds to the major syn-invertomer

observed in solution. Aziridine 3k crystallizes as a single

invertomer with the bulky tert-butylimidoyl moiety located anti- to

the phthalimido group. This is in accordance with positions of the

signals of aziridine ring protons at δ 5.73 (H²) and 3.97 (H³) ppm

3

and the vicinal coupling constant of J = 5.7 Hz. The signals of

the carbon atoms of the aziridine ring are located at δ ~ 45-53

ppm, while the signal of the C²atom of the aziridine ring of the

minor form of compounds 3a-j is not visible due to its strong

broadening.

Trisubstituted aziridines 3l-o exist as a single invertomer

with the syn-location of the phthalimido substituent and the

aziridine proton (imidoyl fragment), as indicated by the downfield

1

singlet at δ 4.77-5.46 ppm in the H NMR spectra. In addition,

the structures of 3m and 3o are unambiguously confirmed by

the X-ray diffraction analysis data (Figure 2).

Next, thermolysis of aziridines 3a-o was carried out in sealed

glass reactors in dry toluene at 110-150 ^oC. Interestingly, while

expected products of the ring expansion (N-sulfonylimidazoles)

do form, they contain the sulfonyl group in an unexpected

position. We observed that heating of aziridines 3a-k yields 2,4-

disubstituted (and not 2,5-disubstituted) N-sulfonylimidazoles

4a-k (Table 3). Products 4a,c,d,e,i have been identified by

comparison of their spectroscopic data to literature reports,²¹

and the structure of 4k is additionally confirmed by the X-ray

diffraction analysis (Fig. S6, ESI). We speculate that 4j is

structurally similar to 4k, since the signal of the heterocyclic

proton is observed at δ 7.35 ppm, which is within the range of

chemical shifts δ 7.11-7.44 ppm for H⁵proton of 4-alkyl-1-

sulfonylimidazoles reported in the literature,²²while the proton

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Scheme 4. A plausible mechanism for the transformation of imidoylaziridines

3 into imidazoles 4.

Scheme 2. Synthesis of imidazole 4c-¹⁵N.

same coupling constant ²J (N,C) = 5.9 Hz, indicating the

equidistance of the phenyls from the labeled nitrogen atom.

To get further insight on the nature of the 1,3-sulfonyl

migration we have performed a crossover experiment heating

equimolar quantities of 3i and 3k at 140 °C in toluene for 4 h

(Scheme 3). According to ¹H NMR, HRMS-ESI and TLC analysis

of the reaction mixture, only products of intramolecular migration

4i,4k form with no detectable amounts of cross-products 4c,4ki

(ESI, S30-32).

Overall, transformation of 3 into 4 proceeds as the

following sequence of reactions: the aziridine ring-opening leads

to azomethine ylide 7 followed by its 1,5-electrocyclization to

imidazoline 8 with a subsequent loss of the phthalimide fragment

and isomerization of imidazole 4' into a less sterically hindered

isomer 4 by the intramolecular 1,3-sulfonyl shift (Scheme 4).

The thermal expansion of imidoylaziridines described above

can serve as a general method for the synthesis of disubstituted,

trisubstituted and condensed N-sulfonylimidazoles. This reaction,

however, is accompanied by the intramolecular 1,3-sulfonyl shift

and for aziridines 3a-k it regioselectively leads to 2,4-

disubstituted N-sulfonylimidazoles 4a-k. The latter can be further

elaborated into the corresponding NH imidazoles or alkylated at

the N-3 atom, after removing the protective sulfonyl group and

forming 1,2,5-trisubstituted imidazoles.²¹

Conclusions

In summary, we have demonstrated that the oxidative

phthalimidoaziridination

of

conjugated

unsaturated

N-

sulfonylimines leads in most cases to di-, trisubstituted and

spirofused imidoylaziridines in good yields. The latter are

transformed to imidazoles upon thermolysis that also brings

about the intramolecular 1,3-sulfonyl shift from one nitrogen

atom to another. Our approach is general and it exploits

transformations of readily available N-sulfonyl-1-azadienes into

N-sulfonylimidazoles by a two-step procedure.

Experimental Section

General information: NMR spectroscopic data were recorded

on the Bruker Avance 400 MHz spectrometer (400.13 MHz for

¹H, 100.61 MHz for ¹³C, 40.54 MHz for ¹⁵N, respectively) Bruker

Avance III 500 MHz (500.03 MHz for ¹H, 125.73 MHz for ¹³C,

respectively) in CDCl₃and CD₂Cl₂solvents. The signals are

referenced to the residual solvent proton (δH = 7.26 and 5.32

ppm, respectively) and carbon (δC = 77.00 and 53.84 ppm,

respectively) signals. Liquid ¹⁵NH₃(δN = 0 ppm) scale was used

for nitrogen NMR spectra. The signals of proton systems AA’XX’

of the para-disubstituted and AA’XX’Y of the monosubstituted

1

phenyl rings are not clearly resolved in the H NMR spectra, and

therefore apparent coupling constants for the observed

“doublets” and “triplets” of the corresponding aromatic protons

are reported. DEPT spectra were used for the assignment of

carbon signals. Melting points were determined with a Stuart

SMP30 instrument. High-resolution mass spectra were recorded

with

a

Bruker Maxis HRMS-ESI-qTOF spectrometer

(electrospray ionization mode). Column chromatography was

performed on silica gel Merck 60. The composition of the

reaction mixtures and fractions obtained after their separation as

well as the purity of the isolated compounds were monitored by

TLC on Alugram SIL G/UV₂₅₄plates (Macherey-Nagel). (E)-1-

Cyclopropyl-3-(4-nitrophenyl)prop-2-en-1-one²⁵,

chlorophenyl)-4,4-dimethylpent-1-en-3-one²⁶,

(E)-1-(4-

(E)-3-aryl-1,2-

diphenylprop-2-en-1-ones²⁷,

(E)-3-aryl-1-phenylprop-2-en-1-

Scheme 3. Crossover experiment indicating intramolecular 1,3-sulfonyl shift.

ones, (E)-2-benzylidene-2,3-dihydro-1H-inden-1-one and (E)-2-

benzylidene-3,4-dihydronaphthalen-1(2H)-one²⁸were prepared

according to the literature procedures.

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General procedure for the preparation of imines 2a-o: A 1.0

М solution of TiCl₄in CH₂Cl₂(5.0 mL, 5 mmol) was added

3H, CH₃); 3.85 (s, 3H, OCH₃); 6.92 (d, J = 8.7 Hz, 2H, H^ar); 7.04

(d, J = 16.0 Hz, 1H, H³); 7.30 (d, J = 8.1 Hz, 2H, H^ar); 7.40-7.45

dropwise to a stirred mixture of α,β-unsaturated ketone (5 mmol), (m, 2H, H^ar); 7.50-7.55 (m, 3H, H^ar); 7.58-7.66 (m, 2H, H^ar); 7.78-

arylsulfonamide (5 mmol) and Et₃N (2.1 mL, 1.5 g, 15 mmol) in

dry CH₂Cl₂(20 mL) at 0 °C. The reaction mixture was warmed to

room temperature and heated under reflux for 18 h. Water (1

mL) was added, the resulted suspension was filtered through

Celite and the solid residue washed with CH₂Cl₂(20 mL). The

resulted solution was washed with water (30 mL), the organic

layer separated and the aqueous one was extracted with CH₂Cl₂

(2×15 mL). The combined organic layers were washed with

water and brine and dried over Na₂SO₄. The solvent was

evaporated under reduced pressure and the residue was

purified by flash (for 2a-k,n,o, eluent - petroleum ether/EtOAc

5:1) or column chromatography (for the separation 2l/2l' and

2m/2m' mixtures, eluent - petroleum ether/EtOAc from 12:1 to

8:1) on silica gel to afford imines 2a-o.

8.10 (m, 3H, H^ar, H²) ppm.

N-[(2E)-1,3-Diphenylprop-2-en-1-ylidene]-4-

nitrobenzenesulfonamide (2f). Yellow crystals, 1.027 g (52%),

mp 161 °C. ¹H NMR (400 MHz, CDCl₃): δ = 7.17 (d, J = 16.0 Hz,

1H, H³); 7.40-7.50 (m, 5H, H^ar); 7.57-7.62 (m, 3H, H^ar); 7.66 (d, J

= 7.5 Hz, 2H, H^ar); 7.84-8.10 (br, 1H, H²); 8.23 (d, J = 8.6 Hz, 2H,

H^ar); 8.37 (d, J = 8.9 Hz, 2H, H^ar) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 122.6 (CH, br); 124.1 (CH); 128.4 (CH); 128.5 (CH);

128.9 (CH); 129.1 (CH); 130.1 (CH, br); 131.6 (CH); 132.4 (CH,

br); 134.2 (C); 136.6 (C, br); 147.2 (C); 150.0 (C); 150.4 (CH);

179.0 (C=N) ppm. HRMS (ESI), m/z: calcd for C₂₁H₁₆N₂O₄S

[M+Na]⁺415.0723, found 415.0731.

4-Chloro-N-[(2E)-1,3-Diphenylprop-2-en-1-

N-[(2E)-3-(4-Nitrophenyl)-1-phenylprop-2-en-1-ylidene]-4-

methylbenzenesulfonamide¹⁷(2a). Yellow crystals, 1.157 g

ylidene]benzenesulfonamide (2g). Beige crystals, 1.204 g

(63%), mp 140-141 °C. H NMR (400 MHz, CDCl₃): δ = 7.11 (d,

1

(57%), mp 148-149 °C (lit. 150-151 °C)¹⁷. H NMR (400 MHz,

J = 16.0 Hz, 1H, H³); 7.39-7.51 (m, 7H, H^ar); 7.54-7.68 (m, 5H,

H^ar); 7.86-8.16 (m, 3H, H^ar, H²) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 122.6 (CH, br); 128.4 (CH); 128.6 (CH); 128.8 (CH);

129.1 (CH); 129.1 (CH); 130.1 (CH, br); 131.3 (CH); 132.1 (CH,

br); 134.4 (C); 137.0 (C, br); 139.1 (C); 140.2 (C); 149.5 (CH);

178.2 (C=N) ppm. HRMS (ESI), m/z: calcd for C₂₁H₁₆ClNO₂S

[M+Na]⁺404.0482, found 404.0467.

1

CDCl₃): δ = 2.44 (s, 3H, CH₃); 7.07 (d, J = 16.2 Hz, 1H, H³); 7.34

(d, J = 8.1 Hz, 2H, H^ar); 7.46 (t, J = 7.6 Hz, 2H, H^ar); 7.58 (t, J =

7.5 Hz, 1H, H^ar); 7.65-7.75 (m, 4H, H^ar); 7.92 (d, J = 7.3 Hz, 2H,

H^ar); 8.08-8.22 (br, 1H, H²); 8.26 (d, J = 8.4 Hz, 2H, H^ar) ppm.

N-[(2E)-3-(4-Chlorophenyl)-1-phenylprop-2-en-1-ylidene]-4-

methylbenzenesulfonamide¹⁷(2b). Beige crystals, 1.225 g

(62%), mp 142 °C (lit. 141-142 °C)¹⁷. ¹H NMR (400 MHz,

CDCl₃): δ = 2.43 (s, 3H, CH₃); 7.01 (d, J = 16.1 Hz, 1H, H³); 7.32

(d, J = 8.0 Hz, 2H, H^ar); 7.38 (d, J = 8.4 Hz, 2H, H^ar); 7.42-7.46

(m, 2H, H^ar); 7.48-7.57 (m, 3H, H^ar); 7.59-7.68 (m, 2H, H^ar); 7.92

(d, J = 7.3 Hz, 2H, H^ar); 7.98-8.16 (br, 1H, H²) ppm.

N-[(2E)-1,3-Diphenylprop-2-en-1-

ylidene]benzenesulfonamide³¹(2h). Beige crystals, 1.027 g

1

(59%), mp 133-134 °C. H NMR (400 MHz, CDCl₃): δ = 7.09 (d,

J = 16.1 Hz, 1H, H³); 7.39-7.48 (m, 5H, H^ar); 7.50-7.71 (m, 8H,

H^ar); 7.90-8.22 (m, 3H, H^ar, H²) ppm.

N-[(2E)-1,3-Diphenylprop-2-en-1-ylidene]-4-

methylbenzenesulfonamide²⁹(2c). Beige crystals, 1.231 g

methoxybenzenesulfonamide³²(2i). Pale yellow crystals,

1

(68%), mp 149-150 °C (lit. 151-152 °C)²⁹. H NMR (400 MHz,

1.275 g (68%), mp 117-118 °C (lit. 119-121 °C)³². H NMR (400

MHz, CDCl₃): δ = 3.86 (s, 3H, OCH₃); 6.98 (d, J = 8.6 Hz, 2H,

H^ar); 7.05 (d, J = 16.0 Hz, 1H, H³); 7.38-7.47 (m, 5H, H^ar); 7.51-

7.70 (m, 5H, H^ar); 7.88-8.20 (m, 3H, H^ar, H²) ppm.

CDCl₃): δ = 2.43 (s, 3H, CH₃); 7.07 (d, J = 16.1 Hz, 1H, H³); 7.32

(d, J = 8.1 Hz, 2H, H^ar); 7.38-7.47 (m, 5H, H^ar); 7.52-7.70 (m, 5H,

H^ar); 7.93 (d, J = 7.3 Hz, 2H, H^ar); 8.00-8.22 (br, 1H, H²) ppm.

4-Methyl-N-[(2E)-3-(4-methylphenyl)-1-phenylprop-2-en-1-

ylidene]benzenesulfonamide (2d). Pale yellow crystals, 1.223

N-[(2E)-1-Cyclopropyl-3-(4-nitrophenyl)prop-2-en-1-ylidene]-

4-methylbenzenesulfonamide (2j). Orange crystals, 1.208 g

1

g (65%), mp 119-120 °C. ¹H NMR (400 MHz, CDCl₃): δ = 2.39 (s, (65%), mp 138-139 °C . H NMR (400 MHz, CDCl₃): δ = 1.06-

3H, CH₃); 2.42 (s, 3H, CH₃); 7.05 (d, J = 16.0 Hz, 1H, H³); 7.22

(d, J = 8.0 Hz, 2H, H^ar); 7.31 (d, J = 8.1 Hz, 2H, H^ar); 7.40-7.49

(m, 4H, H^ar); 7.52-7.56 (m, 1H, H^ar); 7.58-7.68 (m, 2H, H^ar); 7.93

(d, J = 7.5 Hz, 2H, H^ar); 7.98-8.18 (br, 1H, H²) ppm. ¹³C NMR

(100 MHz, CDCl₃): δ = 21.52 (CH₃); 21.54 (CH₃); 121.7 (CH, br);

127.2 (CH); 128.3 (CH); 128.8 (CH); 129.4 (CH); 129.8 (CH);

130.1 (CH, br); 131.7 (CH, br); 131.9 (C); 137.2 (C, br); 138.9

(C); 141.8 (C); 143.3 (C); 149.2 (CH); 177.8 (C=N) ppm. HRMS

(ESI), m/z: calcd for C₂₃H₂₂NO₂S [M+H]⁺376.1366, found

376.1363.

1.28 (m, 4H, CH₂, c-Pr); 2.18-2.38 (br, 1H, CH, c-Pr); 2.43 (s, 3H,

CH₃); 7.31 (d, J = 8.1 Hz, 2H, H^ar); 7.59 (d, J = 16.1 Hz, 1H, H³);

7.70-7.78 (m, 2H, H^ar); 7.83 (d, J = 7.9 Hz, 2H, H^ar); 7.92-8.18

(br, 1H, H²); 8.27 (d, J = 8.6 Hz, 2H, H^ar) ppm. ¹³C NMR (100

MHz, CDCl₃): δ = 13.4 (CH₂, br); 16.8 (CH, br); 21.5 (CH₃);

124.2 (CH); 126.8 (CH); 127.1 (CH, br); 129.0 (CH); 129.4 (CH);

138.7 (C); 140.3 (CH); 140.8 (C); 143.4 (C); 148.6 (C); 181.8

(C=N) ppm. HRMS (ESI), m/z: calcd for C₁₉H₁₈N₂O₄S [M+H]⁺

371.1060, found 371.1063.

N-[(1E,2E)-1-tert-butyl-3-(4-chlorophenyl)prop-2-en-1-

N-[(2E)-3-(4-Methoxylphenyl)-1-phenylprop-2-en-1-ylidene]-

4-methylbenzenesulfonamide³⁰(2e). Yellow crystals, 1.386 g

(71%), mp 128-129 °C. H NMR (400 MHz, CDCl₃): δ = 2.42 (s,

ylidene]-4-methylbenzenesulfonamide (2k). Colorless crystals,

1.384 g (74%), mp 151 °C . ¹H NMR (400 MHz, CDCl₃): δ = 1.24

(s, 9H, C(CH₃)₃); 2.42 (s, 3H, CH₃); 7.04 (d, J = 16.6 Hz, 1H, H³);

1

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7.27-7.38 (m, 5H, H^ar, H²); 7.46 (d, J = 8.5 Hz, 2H, H^ar); 7.85 (d,

J = 8.3 Hz, 2H, H^ar) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 21.5

(CH₃); 28.3 (C(CH₃)₃); 42.7 (C(CH₃)₃); 121.9 (CH); 126.9 (CH);

128.9 (CH); 129.1 (CH); 129.3 (CH); 133.6 (C); 135.7 (C); 139.1

(C); 140.0 (CH); 143.1 (C); 189.3 (C=N) ppm. HRMS (ESI), m/z:

calcd for C₂₀H₂₂ClNO₂S [M+H]⁺376.1133, found 376.1134.

MHz, CD₂Cl₂, 298K): δ = 2.29 (s, 3H, CH₃); 2.41 (s, 3H, CH₃);

1

6.68-8.08 (m, 19H, H^ar, =CH) ppm. H NMR (500 MHz, CD₂Cl₂,

252K): δ = 2.22 (s, CH₃), 2.26 (s, CH₃), 2.32 (s, CH₃), 2.35 (s,

CH₃), 2.38 (s, CH₃), 2.46 (s, CH₃), in sum 6H; 6.77 (d, J = 7.9 Hz,

H^ar), 6.90-7.58 (m, =CH, H^ar), 7.81 (d, J = 7.6 Hz, H^ar), 7.95 (d, J

= 7.8 Hz, H^ar), 8.03 (d, J = 7.7 Hz, H^ar), in sum 19H, ppm. ¹³C

NMR (100 MHz, CD₂Cl₂, 298K): δ = 21.5 (CH₃); 21.7 (CH₃);

127.3 (C); 128.3 (CH); 128.5 (C); 129.0 (CH); 129.4 (CH); 129.7

(CH); 130.5 (CH); 130.8 (C); 132.5 (C); 136.3 (C); 139.5 (C) ppm.

Some signals of carbon atoms are not seen due to strong

broadening at room temperature. ¹³C NMR (125 MHz, CD₂Cl₂,

252K): δ = 21.2 (CH₃); 21.3 (CH₃); 21.4 (CH₃); 21.57 (CH₃);

21.59 (CH₃); 126.2 (CH); 126.6 (CH); 127.3 (CH); 127.6 (CH);

127.9 (CH); 128.3 (CH); 128.6 (CH); 128.7 (CH); 128.8 (CH);

128.9 (CH); 129.0 (CH); 129.09 (CH); 129.12 (CH); 129.2 (CH);

129.38 (CH); 129.43 (CH); 129.7 (CH); 130.0 (CH); 130.05 (CH);

130.13 (CH); 130.33 (CH); 130.35 (CH); 131.2 (CH); 131.8 (C);

132.2 (C); 132.3 (C); 133.3 (CH); 133.8 (C); 134.2 (CH); 134.8

(CH); 135.0 (C); 135.54 (C); 135.56 (C); 135.7 (C); 136.6 (C);

137.0 (C); 138.1 (C); 138.6 (C); 138.7 (C); 138.8 (C); 140.8 (C);

141.9 (C); 143.3 (C); 144.0 (C); 144.3 (C); 148.3 (CH); 177.7

(C=N); 179.6 (C=N); 181.4 (C=N) ppm. HRMS (ESI), m/z: calcd

for C₂₉H₂₅NO₂S [M+H]⁺452.1679, found 452.1683.

N-[(2E)-3-(4-Chlorophenyl)-1,2-diphenylprop-2-en-1-ylidene]-

4-methylbenzenesulfonamide (2l). Pale yellow crystals, 1.206

1

g (51%), mp 136-137 °C. According to the H NMR spectrum,

imine 2l exists as a mixture of three forms in the ratio

1:0.64:0.21 at -21 °C, probably E/Z isomers about the C=N bond

with s-trans-conformation of the C=C–C=N fragment and s-cis-

conformer with undefined configuration of the C=N bond. ¹H

NMR (400 MHz, CD₂Cl₂, 298K): δ = 2.43 (s, 3H, CH₃); 6.74-8.06

(m, 19H, H^ar, =CH) ppm. ¹H NMR (500 MHz, CD₂Cl₂, 252K): δ =

2.35 (s, CH₃), 2.39 (s, CH₃), 2.46 (s, CH₃), in sum 3H; 6.83 (d, J

= 8.4 Hz, H^ar), 6.94 (s, =CH), 7.07-7.58 (m, =CH, H^ar), 7.82 (d, J

= 7.6 Hz, H^ar), 7.96 (d, J = 8.1 Hz, H^ar), 8.02 (d, J = 7.6 Hz, H^ar),

in sum 19H, ppm. ¹³C NMR (100 MHz, CD₂Cl₂, 298K): δ = 21.3

(CH₃); 127.5 (C); 128.6 (CH); 128.9 (CH); 129.1 (CH); 129.8

(CH); 130.4 (CH); 131.9 (C); 136.0 (C); 139.2 (C) ppm. Some

signals of carbon atoms are not seen due to strong broadening

at room temperature. ¹³C NMR (125 MHz, CD₂Cl₂, 252K): δ =

21.5 (CH₃); 21.59 (CH₃); 21.61 (CH₃); 126.3 (CH); 126.6 (CH);

127.3 (CH); 127.6 (CH); 128.0 (CH); 128.1 (CH); 128.50 (CH);

128.54 (CH); 128.6 (CH); 128.69 (CH); 128.74 (CH); 128.8 (CH);

128.86 (CH); 128.92 (CH); 129.0 (CH); 129.2 (CH); 129.3 (CH);

129.5 (CH); 129.8 (CH); 130.0 (CH); 130.1 (CH); 130.2 (CH);

130.3 (CH); 130.5 (CH); 131.4 (CH); 132.3 (CH); 133.0 (CH);

133.3 (C); 133.5 (CH); 133.8 (C); 134.0 (C); 134.4 (CH); 134.8

(C); 135.0 (C); 135.2 (C); 135.3 (C); 135.4 (C); 135.8 (C); 136.26

(C); 136.33 (C); 137.7 (C); 138.2 (C); 138.4 (C); 138.5 (C); 143.3

(C); 143.4 (C); 144.2 (C); 144.5 (C); 146.1 (CH); 177.1 (C=N);

178.9 (C=N); 181.1 (C=N) ppm. HRMS (ESI), m/z: calcd for

C₂₈H₂₂ClNO₂S [M+H]⁺472.1133, found 472.1128.

4-Methyl-N-[(1Z,2Z)-3-(4-methylphenyl)-1,2-diphenylprop-2-

en-1-ylidene]benzenesulfonamide (2m'). Yellow crystals,

0.390 g (17%), mp 167 °C. ¹H NMR (400 MHz, CDCl₃): δ = 2.26

(s, 3H, CH₃); 2.38 (s, 3H, CH₃); 6.97 (d, J = 8.0 Hz, 2H, H^ar);

7.14 (d, J = 8.0 Hz, 2H, H^ar); 7.20 (d, J = 8.2 Hz, 2H, H^ar); 7.27-

7.36 (m, 6H, =CH, H^ar); 7.38-7.43 (m, 2H, H^ar); 7.44-7.50 (m, 1H,

H^ar); 7.60 (d, J = 8.2 Hz, 2H, H^ar); 8.03-8.07 (m, 2H, H^ar) ppm.

¹³C NMR (100 MHz, CDCl₃): δ = 21.2 (CH₃); 21.5 (CH₃); 126.3

(CH); 127.8 (CH); 127.9 (CH); 128.7 (CH); 128.8 (CH); 128.9

(CH); 129.1 (CH); 129.2 (CH); 130.1 (CH); 130.5 (CH); 132.5

(C); 133.7 (CH); 134.3 (C); 135.4 (C); 137.0 (C); 138.2 (C);

138.3 (C); 143.5 (C); 177.4 (C=N) ppm. HRMS (ESI), m/z: calcd

for C₂₉H₂₅NO₂S [M+H]⁺452.1679, found 452.1691.

N-[(1Z,2Z)-3-(4-Chlorophenyl)-1,2-diphenylprop-2-en-1-

ylidene]-4-methylbenzenesulfonamide (2l'). Yellow crystals,

0.469 g (20%), mp 156 °C. ¹H NMR (400 MHz, CDCl₃): δ = 2.40

(s, 3H, CH₃); 7.09-7.13 (m, 2H, H^ar); 7.16 (d, J = 8.1 Hz, 2H, H^ar);

7.19-7.23 (m, 2H, H^ar); 7.24 (s, 1H, =CH); 7.30-7.37 (m, 5H, H^ar);

7.39-7.43 (m, 2H, H^ar); 7.46-7.52 (m, 1H, H^ar); 7.59 (d, J = 8.3

Hz, 2H, H^ar); 8.00-8.04 (m, 2H, H^ar) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 21.5 (CH₃); 126.4 (CH); 127.7 (CH); 128.4 (CH);

128.7 (CH); 128.8 (CH); 129.0 (CH); 129.1 (CH); 129.2 (CH);

130.0 (CH); 130.1 (CH); 133.8 (C); 133.9 (CH); 134.0 (C); 135.2

N-[(2E)-2-Benzylidene-2,3-dihydro-1H-inden-1-ylidene]-4-

methylbenzenesulfonamide (2n). Beige crystals, 1.208 g

(65%), mp 177-178 °C. H NMR (400 MHz, CDCl₃): δ = 2.47 (s,

1

3H, CH₃); 4.05 (s, 2H, CH₂); 7.35-7.55 (m, 7H, H^ar); 7.58-7.65 (m,

3H, H^ar); 7.84 (s, 1H, =CH); 8.03 (d, J = 8.2 Hz, 2H, H^ar); 8.90 (d,

J = 7.8 Hz, 1H, H^ar) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 21.5

(CH₃); 34.2 (CH₂); 125.6 (CH); 126.8 (CH); 127.9 (CH); 128.9

(CH); 129.3 (CH); 129.7 (CH); 130.4 (CH); 130.7 (CH); 134.4

(C); 135.0 (CH); 135.36 (C); 135.43 (CH); 136.4 (C); 140.1 (C);

(C); 136.3 (C); 136.8 (C); 137.9 (C); 143.8 (C); 176.8 (C=N) ppm. 142.8 (C); 150.4 (C); 175.6 (C=N) ppm. HRMS (ESI), m/z: calcd

HRMS (ESI), m/z: calcd for C₂₈H₂₂ClNO₂S [M+H]⁺472.1133,

for C₂₃H₁₉NO₂S [M+H]⁺374.1209, found 374.1217.

found 472.1132.

N-[(2E)-2-benzylidene-3,4-dihydronaphthalen-1(2H)-ylidene]-

4-methylbenzenesulfonamide³³(2o). Cream crystals, 1.485 g

4-Methyl-N-[(2E)-3-(4-methylphenyl)-1,2-diphenylprop-2-en-

1-ylidene]benzenesulfonamide (2m). Cream crystals, 1.132 g

(50%), mp 135 °C. According to the ¹H NMR spectrum, imine

2m exists as a mixture of three forms in the ratio 1:0.64:0.21 at -

21 °C, probably E/Z-isomers about the C=N bond with s-trans-

conformation of the C=C–C=N fragment and s-cis-conformer

with undefined configuration of the C=N bond. ¹H NMR (400

1

(77%), mp 131-132 °C (lit. 132-133 °C)³³. H NMR (400 MHz,

CDCl₃): δ = 2.44 (s, 3H, CH₃); 2.98 (s, 4H, CH₂); 7.19 (d, J = 7.6

Hz, 1H, H^ar); 7.24-7.48 (m, 9H, H^ar, CHCl₃); 7.85 (s, 1H, =CH);

7.95 (d, J = 8.3 Hz, 2H, H^ar); 8.17 (dd, J = 8.0 Hz, J = 0.8 Hz, 1H,

H^ar) ppm.

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General procedure for the preparation of aziridines 3a-o: N-

Aminophthalimide (0.648 g, 4 mmol) was added to a stirred

suspension of K₂CO₃(2.8 g, 20 mmol) in a solution of imine 2a-o

(2 mmol) in dry CH₂Cl₂(50 mL) at 0 °C followed by addition of

Pb(OAc)₄(1.772 g, 4 mmol) in small portions within 10 min.

Upon completion, the stirring was continued for 45 min at the

same temperature, and then the inorganic precipitate was

filtered off. The solid was washed with CH₂Cl₂and combined

filtrates concentrated under reduced pressure to 4-5 mL. The

crystalline product was isolated by the addition of methanol (15

mL) to this solution (aziridines decompose on silica gel during

the flash chromatography). The precipitate was filtered, washed

with methanol (3×5 mL), and dried in vacuo.

(CH, major); 129.1 (CH, major); 129.5 (CH, minor); 129.6 (C,

minor); 129.8 (C, major); 131.4 (CH, minor); 132.0 (CH, major);

133.5 (C, major); 133.6 (CH, major); 134.3 (CH, minor); 134.6 (C,

major); 135.2 (C, minor); 135.3 (C, minor); 137.2 (C, major);

137.4 (C, major); 137.9 (C, minor); 143.0 (C, major); 143.9 (C,

minor); 164.3 (CON, major); 174.2 (C=N, major) ppm. Signals of

the major and minor isomers partially overlap and several

signals of the carbon atoms of the minor form are not resolved.

HRMS (ESI), m/z: calcd for C₃₀H₂₂ClN₃O₄S [M+Na]⁺578.0912,

found 578.0922.

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-phenylaziridin-2-

yl](phenyl)methylene]-4-methylbenzenesulfonamide

(3c).

Cream crystals, 0.811 g (78%), mp 170-171 °C. According to the

¹H NMR spectrum it exists as a mixture of invertomers in the

ratio of 1:0.21. ¹H NMR (400 MHz, CDCl₃): δ = 2.26 (s, 3H, CH₃,

major); 2.42 (s, 3H, CH₃, minor); 3.83 (d, J = 4.8 Hz, 1H, H²,

major); 4.08 (d, J = 5.5 Hz, 1H, H³, minor); 4.78 (d, J = 4.8 Hz,

1H, H³, major); 5.72-6.08 (br, 1H, H², minor); 6.81 (d, J = 8.0 Hz,

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-(4-

nitrophenyl)aziridin-2-yl](phenyl)methylene]-4-

methylbenzenesulfonamide (3a). Pale yellow crystals, 0.947 g

(84%), mp 195-196 °C. According to the ¹H NMR spectrum it

1

exists as a mixture of invertomers in the ratio of 1:0.19. H NMR

(400 MHz, CDCl₃): δ = 2.26 (s, 3H, CH₃, major); 2.43 (s, 3H, CH₃, 2H, H^ar, major); 7.23-7.26 (m, 3H, H^ar, minor, CHCl₃); 7.29-7.42

minor); 3.83 (d, J = 4.6 Hz, 1H, H², major); 4.14 (d, J = 5.5 Hz,

1H, H³, minor); 4.86 (d, J = 4.6 Hz, 1H, H³, major); 5.82-6.06 (br,

1H, H², minor); 6.82 (d, J = 8.1 Hz, 2H, H^ar, major); 7.31-7.43 (m,

2H, H^ar, major, 4H, H^ar, minor); 7.48-7.72 (m, 9H, H^ar, major, 7H,

(m, 5H, H^ar, major, 4H, H^ar, minor); 7.44-7.69 (m, 9H, H^ar, major,

7H, H^ar, minor); 7.89 (d, J = 8.2 Hz, 2H, H^ar, minor); 8.01-8.10 (m,

2H, H^ar, major, 2H, H^ar, minor) ppm. ¹³C NMR (100 MHz, CDCl₃):

δ = 21.5 (CH₃); 52.56 (CH, major); 52.58 (CH, major); 52.9 (CH,

H^ar, minor); 7.88 (d, J = 8.2 Hz, 2H, H^ar, minor); 8.03-8.10 (m, 2H, minor); 123.0 (CH, major); 123.1 (CH, minor); 126.7 (CH, major);

H^ar, major, 2H, H^ar, minor); 8.13 (d, J = 8.8 Hz, 2H, H^ar, minor);

8.22-8.27 (m, 2H, H^ar, major) ppm. ¹³C NMR (100 MHz, CDCl₃):

δ = 21.6 (CH₃); 50.9 (CH, major); 51.6 (CH, minor); 52.7 (CH,

major); 123.2 (CH, major); 123.3 (CH, minor); 123.5 (CH, minor);

123.9 (CH, major); 126.8 (CH, major); 127.2 (CH, minor); 128.2

(CH, major); 128.3 (CH, minor); 128.4 (CH, major); 129.0 (C,

minor); 129.1 (CH, major); 129.6 (CH, minor); 129.7 (C, major);

131.1 (CH, minor); 132.2 (CH, major); 133.7 (CH, major); 134.6

(CH, minor); 136.86 (C, minor); 136.91 (C, major); 137.3 (C,

major); 142.2 (C, major); 143.1 (C, major); 148.1 (C, major);

164.3 (CON, major); 173.5 (C=N, major) ppm. Signals of the

major and minor isomers partially overlap and several signals of

the carbon atoms of the minor form are not resolved. HRMS

(ESI), m/z: calcd for C₃₀H₂₂N₄O₆S [M+Na]⁺589.1152, found

589.1159.

127.2 (CH, major); 127.3 (CH, minor); 128.17 (CH, minor);

128.19 (CH, minor); 128.3 (CH, major); 128.6 (CH, major); 128.7

(CH, major); 128.96 (CH, major); 129.03 (CH, major); 129.2 (CH,

minor); 129.4 (CH, minor); 129.7 (C, minor); 129.8 (C, major);

130.0 (CH, minor); 131.9 (CH, major); 133.5 (CH, major); 134.1

(CH, minor); 134.9 (C, major); 135.4 (C, minor); 137.4 (C,

major); 137.5 (C, major); 138.0 (C, minor); 142.9 (C, major);

143.7 (C, minor); 164.3 (CON, major); 174.7 (C=N, major) ppm.

Signals of the major and minor isomers partially overlap and

several signals of the carbon atoms of the minor form are not

resolved. HRMS (ESI), m/z: calcd for C₃₀H₂₃N₃O₄S [M+H]⁺

522.1482, found 522.1496.

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-(4-

methylphenyl)aziridin-2-yl](phenyl)methylene]-4-

methylbenzenesulfonamide (3d). Pale yellow crystals, 0.803 g

(75%), mp 177-178 °C. According to the ¹H NMR spectrum it

exists as a mixture of invertomers in the ratio of 1:0.25. H NMR

N-[[rel-(2R,3S)-3-(4-Сhlorophenyl)-1-(1,3-Dioxoisoindol-2-yl)-

)aziridin-2-yl](phenyl)methylene]-4-

1

methylbenzenesulfonamide (3b). Cream crystals, 0.909 g

(82%), mp 184-185 °C. According to the ¹H NMR spectrum it

(400 MHz, CDCl₃): δ = 2.24 (s, 3H, CH₃, minor); 2.25 (s, 3H, CH₃,

major); 2.35 (s, 3H, CH₃, major); 2.42 (s, 3H, CH₃, minor); 3.81

(d, J = 4.8 Hz, 1H, H², major); 4.03 (d, J = 5.5 Hz, 1H, H³,

1

exists as a mixture of invertomers in the ratio of 1:0.24. H NMR

(400 MHz, CDCl₃): δ = 2.25 (s, 3H, CH₃, major); 2.42 (s, 3H, CH₃, minor); 4.75 (d, J = 4.8 Hz, 1H, H³, major); 5.62-6.05 (br, 1H, H²,

minor); 3.79 (d, J = 4.7 Hz, 1H, H², major); 4.04 (d, J = 5.4 Hz,

1H, H³, minor); 4.74 (d, J = 4.7 Hz, 1H, H³, major); 5.68-6.08 (br,

1H, H², minor); 6.80 (d, J = 8.0 Hz, 2H, H^ar, major); 7.22-7.26 (m,

2H, H^ar, minor, CHCl₃); 7.29-7.45 (m, 6H, H^ar, major, 6H, H^ar,

minor); 7.46-7.62 (m, 7H, H^ar, major, 1H, H^ar, minor); 7.64-7.72

(m, 4H, H^ar, minor); 7.89 (d, J = 8.1 Hz, 2H, H^ar, minor); 8.00-

minor); 6.81 (d, J = 8.1 Hz, 2H, H^ar, major); 7.06 (d, J = 7.9 Hz,

2H, H^ar, minor); 7.19 (d, J = 8.0 Hz, 2H, H^ar, major); 7.28-7.42 (m,

4H, H^ar, major, 6H, H^ar, minor); 7.45-7.69 (m, 7H, H^ar, major, 5H,

H^ar, minor); 7.89 (d, J = 8.2 Hz, 2H, H^ar, minor); 8.01-8.10 (m, 2H,

H^ar, major, 2H, H^ar, minor) ppm. ¹³C NMR (100 MHz, CDCl₃): δ =

21.2 (CH₃); 21.5 (CH₃); 52.57 (CH, major); 52.60 (CH, major);

8.10 (m, 2H, H^ar, major, 2H, H^ar, minor) ppm. ¹³C NMR (100 MHz, 52.8 (CH, minor); 122.9 (CH, major); 123.1 (CH, minor); 126.1

CDCl₃): δ = 21.5 (CH₃); 51.7 (CH, major); 52.1 (CH, minor); 52.5

(CH, major); 123.0 (CH, major); 123.3 (CH, minor); 126.7 (CH,

major); 127.2 (CH, minor); 128.2 (CH, minor); 128.3 (CH, major);

128.5 (CH, minor); 128.6 (CH, major); 128.8 (CH, major); 129.0

(C, minor); 126.7 (CH, major); 127.0 (CH, major); 127.2 (CH,

minor); 128.1 (CH, minor); 128.3 (CH, major); 128.9 (CH, major);

128.98 (CH, minor); 129.01 (CH, major); 129.3 (CH, major);

129.4 (CH, minor); 129.76 (CH, minor); 129.83 (C, major); 131.8

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(CH, major); 131.9 (C, major); 133.4 (CH, major); 134.0 (CH,

minor); 135.4 (C, minor); 137.4 (C, major); 137.5 (C, major);

138.0 (C, minor); 138.6 (C, major); 139.0 (C, minor); 142.8 (C,

major); 143.7 (C, minor); 164.3 (CON, major); 174.8 (C=N,

major) ppm. Signals of the major and minor isomers partially

overlap and several signals of the carbon atoms of the minor

form are not resolved. HRMS (ESI), m/z: calcd for C₃₁H₂₅N₃O₄S

[M+H]⁺536.1639, found 536.1641.

the major and minor isomers partially overlap and several

signals of the carbon atoms of the minor form are not resolved.

HRMS (ESI), m/z: calcd for C₂₉H₂₀N₄O₆S [M+H]⁺553.1176,

found 553.1168.

4-Сhloro-N-[[rel-(2R,3S)-1-(1,3-dioxoisoindol-2-yl)-3-

phenylaziridin-2-yl](phenyl)methylene]benzenesulfonamide

(3g). Cream crystals, 0.844 g (78%), mp 161-162 °C. According

1

to the H NMR spectrum it exists as a mixture of invertomers in

1

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-(4-

the ratio of 1:0.14. H NMR (400 MHz, CDCl₃): δ = 3.85 (d, J =

methoxylphenyl)aziridin-2-yl](phenyl)methylene]-4-

methylbenzenesulfonamide (3e). Yellow crystals, 0.835 g

(76%), mp 172-174 °C. According to the ¹H NMR spectrum it

4.8 Hz, 1H, H², major); 4.09 (d, J = 5.5 Hz, 1H, H³, minor); 4.80

(d, J = 4.8 Hz, 1H, H³, major); 5.64-6.06 (br, 1H, H², minor);

6.95-6.99 (m, 2H, H^ar, major); 7.25-7.29 (m, 3H, H^ar, minor,

CHCl₃); 7.33-7.68 (m, 14H, H^ar, major, 11H, H^ar, minor); 7.93-

1

exists as a mixture of invertomers in the ratio of 1:0.33. H NMR

(400 MHz, CDCl₃): δ = 2.25 (s, 3H, CH₃, major); 2.42 (s, 3H, CH₃, 7.97 (m, 2H, H^ar, minor); 8.03-8.11 (m, 2H, H^ar, major, 2H, H^ar,

minor); 3.72 (s, 3H, OCH₃, minor); 3.79-3.82 (m, 4H, H², OCH₃,

major); 4.03 (d, J = 5.5 Hz, 1H, H³, minor); 4.72 (d, J = 4.8 Hz,

1H, H³, major); 5.68-5.98 (br, 1H, H², minor); 6.76-6.83 (m, 2H,

H^ar, major, 2H, H^ar, minor); 6.90 (d, J = 8.7 Hz, 2H, H^ar, major);

7.29-7.42 (m, 4H, H^ar, major, 6H, H^ar, minor); 7.46-7.69 (m, 7H,

H^ar, major, 5H, H^ar, minor); 7.89 (d, J = 8.3 Hz, 2H, H^ar, minor);

8.00-8.09 (m, 2H, H^ar, major, 2H, H^ar, minor) ppm. ¹³C NMR (100

MHz, CDCl₃): δ = 21.6 (CH₃); 52.5 (CH, major); 52.6 (CH,

major); 52.7 (CH, minor); 55.2 (OCH₃, minor); 55.4 (OCH₃,

major); 113.7 (CH, minor); 114.1 (CH, major); 123.0 (CH, major);

123.1 (CH, minor); 126.8 (CH, major); 126.9 (C, major); 127.3

(CH, minor); 128.2 (CH, minor); 128.3 (CH, major); 128.5 (CH,

major); 129.0 (CH, major); 129.1 (CH, major); 129.5 (CH, minor);

129.9 (C, major); 131.4 (CH, minor); 131.9 (CH, major); 133.5

(CH, major); 134.1 (CH, minor); 137.5 (C, major); 137.6 (C,

major); 142.9 (C, major); 160.0 (C, major); 160.2 (C, minor);

164.4 (CON, major); 174.9 (C=N, major) ppm. Signals of the

major and minor isomers partially overlap and several signals of

the carbon atoms of the minor form are not resolved. HRMS

(ESI), m/z: calcd for C₃₁H₂₅N₃O₅S [M+H]⁺552.1588, found

552.1593.

minor) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 52.5 (CH, major);

52.8 (CH, major); 53.0 (CH, minor); 123.05 (CH, major); 123.10

(CH, minor); 127.1 (CH, major); 128.2 (CH, major); 128.25 (CH,

minor); 128.29 (CH, minor); 128.4 (CH, major); 128.68 (CH,

major); 128.71 (CH, major); 128.8 (CH, major); 129.0 (CH,

major); 129.1 (CH, minor); 129.3 (CH, minor); 129.6 (C, major);

129.7 (C, minor); 129.9 (CH, minor); 132.2 (CH, major); 133.9

(CH, major); 134.1 (CH, minor); 134.7 (C, major); 135.2 (C,

minor); 137.2 (C, major); 138.9 (C, major); 139.42 (C, minor);

139.45 (C, minor); 164.2 (CON, major); 175.7 (C=N, major) ppm.

Signals of the major and minor isomers partially overlap and

several signals of the carbon atoms of the minor form are not

resolved. HRMS (ESI), m/z: calcd for C₂₉H₂₀ClN₃O₄S [M+H]⁺

542.0936, found 542.0949.

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-phenylaziridin-2-

yl](phenyl)methylene]-benzenesulfonamide

(3h). Cream

crystals, 0.702 g (69%), mp 164-165 °C. According to the ¹H

NMR spectrum it exists as a mixture of invertomers in the ratio of

1

1:0.25. H NMR (400 MHz, CDCl₃): δ = 3.84 (d, J = 4.8 Hz, 1H,

H², major); 4.10 (d, J = 5.5 Hz, 1H, H³, minor); 4.79 (d, J = 4.8

Hz, 1H, H³, major); 5.66-6.10 (br, 1H, H², minor); 7.05 (t, J = 7.8

Hz, 2H, H^ar, major); 7.20-7.29 (m, 1H, H^ar, major, 3H, H^ar, minor,

CHCl₃); 7.32-7.68 (m, 14H, H^ar, major, 12H, H^ar, minor); 8.00-

8.10 (m, 2H, H^ar, major, 4H, H^ar, minor) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 52.6 (CH, 2 overlapping signals, major); 53.0 (CH,

minor); 123.1 (CH, major); 126.6 (CH, major); 127.16 (CH,

major); 127.18 (CH, minor); 128.2 (CH, minor); 128.3 (CH,

major); 128.4 (CH, major); 128.6 (CH, major); 128.7 (CH, major);

128.8 (CH, minor); 128.9 (CH, major); 129.2 (CH, minor); 129.7

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-phenylaziridin-2-

yl](phenyl)methylene]-4-nitrobenzenesulfonamide

(3f).

Cream crystals, 0.871 g (79%), mp 168-169 °C. According to the

¹H NMR spectrum it exists as a mixture of invertomers in the

1

ratio of 1:0.16. H NMR (400 MHz, CDCl₃): δ = 3.87 (d, J = 4.8

Hz, 1H, H², major); 4.11 (d, J = 5.4 Hz, 1H, H³, minor); 4.76 (d, J

= 4.8 Hz, 1H, H³, major); 5.72-5.94 (br, 1H, H², minor); 7.26-7.29

(m, 3H, H^ar, minor, CHCl₃); 7.33-7.71 (m, 14H, H^ar, major, 9H,

H^ar, minor); 7.84 (d, J = 8.8 Hz, 2H, H^ar, major); 8.05-8.11 (m, 2H, (C, minor); 129.8 (C, major); 130.0 (CH, minor); 131.9 (CH,

H^ar, major, 2H, H^ar, minor); 8.21 (d, J = 8.8 Hz, 2H, H^ar, minor);

8.37 (d, J = 8.8 Hz, 2H, H^ar, minor) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 52.5 (CH, major); 53.1 (CH, minor); 53.3 (CH,

major); 123.0 (CH, major); 123.2 (CH, minor); 123.7 (CH, major);

124.1 (CH, minor); 127.1 (CH, major); 128.0 (CH, major); 128.4

(CH, minor); 128.46 (CH, minor); 128.54 (CH, major); 128.8 (CH,

major); 128.9 (CH, major); 129.1 (CH, major); 129.4 (CH, minor);

129.7 (C, major); 129.9 (CH, minor); 130.1 (CH, minor); 132.7

(CH, major); 133.4 (CH, minor); 134.1 (CH, major); 134.2 (CH,

minor); 134.5 (C, major); 134.9 (C, minor); 137.1 (C, major);

145.9 (C, major); 146.5 (C, minor); 149.6 (C, major); 150.2 (C,

minor); 164.1 (CON, major); 177.3 (C=N, major) ppm. Signals of

major); 132.4 (CH, major); 132.9 (CH, minor); 133.8 (CH, major);

134.1 (CH, minor); 134.8 (C, major); 135.3 (C, minor); 137.3 (C,

major); 140.3 (C, major); 140.9 (C, minor); 164.3 (CON, major);

165.2 (CON, minor); 175.2 (C=N, major) ppm. Signals of the

major and minor isomers partially overlap and several signals of

the carbon atoms of the minor form are not resolved. HRMS

(ESI), m/z: calcd for C₂₉H₂₁N₃O₄S [M+H]⁺508.1326, found

508.1343.

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-phenylaziridin-2-

yl](phenyl)methylene]-4-methoxybenzenesulfonamide (3i).

Pale yellow crystals, 0.766 g (71%), mp 162-163 °C. According

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European Journal of Organic Chemistry

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1

to the H NMR spectrum it exists as a mixture of invertomers in

8.2 Hz, 2H, H^ar); 7.42 (d, J = 8.6 Hz, 2H, H^ar); 7.61-7.69 (m, 4H,

H^ar); 7.84 (d, J = 8.2 Hz, 2H, H^ar) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 21.5 (CH₃); 27.6 (C(CH₃)₃); 44.0 (C(CH₃)₃); 44.7

(CH); 52.6 (CH); 123.1 (CH); 126.9 (CH); 128.2 (C); 128.4 (CH);

129.4 (CH); 131.4 (CH); 134.2 (CH); 135.2 (C); 138.4 (C); 143.5

(C); 165.1 (CON); 189.6 (C=N) ppm. HRMS (ESI), m/z: calcd for

C₂₈H₂₆ClN₃O₄S [M+Na]⁺558.1225, found 558.1233.

1

the ratio of 1:0.19. H NMR (400 MHz, CDCl₃): δ = 3.76 (s, 3H,

OCH₃, major); 3.81 (d, J = 4.8 Hz, 1H, H², major); 3.86 (s, 3H,

OCH₃, minor); 4.07 (d, J = 5.5 Hz, 1H, H³, minor); 4.81 (d, J =

4.8 Hz, 1H, H³, major); 5.68-6.10 (br, 1H, H², minor); 6.45-6.50

(m, 2H, H^ar, major); 6.95-6.99 (m, 2H, H^ar, minor); 7.24-7.28 (m,

3H, H^ar, minor, CHCl₃); 7.31-7.68 (m, 14H, H^ar, major, 9H, H^ar,

minor); 7.93 (d, J = 8.9 Hz, 2H, H^ar, minor); 8.00-8.08 (m, 2H, H^ar,

major, 2H, H^ar, minor) ppm. ¹³C NMR (100 MHz, CDCl₃): δ =

52.5 (CH, major); 52.6 (CH, major); 52.9 (CH, minor); 55.3

(OCH₃, major); 55.6 (OCH₃, minor); 113.6 (CH, major); 114.0

(CH, minor); 123.0 (CH, major); 123.1 (CH, minor); 127.2 (CH,

major); 128.17 (CH, minor); 128.20 (CH, minor); 128.3 (CH,

major); 128.65 (CH, major); 128.68 (CH, major); 128.91 (CH,

major); 128.94 (CH, major); 129.2 (CH, minor); 129.5 (CH,

minor); 129.9 (C, major); 130.0 (CH, minor); 131.8 (CH, major);

N-[[rel-(2R,3S)-3-(4-Chlorophenyl)-1-(1,3-dioxoisoindol-2-yl)-

2-phenylaziridin-2-yl](phenyl)methylene]-4-

methylbenzenesulfonamide (3l). Cream crystals, 0.948 g

(75%), mp 170-171 °C. ¹H NMR (400 MHz, CD₂Cl₂): δ = 2.31 (s,

3H, CH₃); 5.46 (s, 1H, CH); 6.88 (d, J = 8.0 Hz, 2H, H^ar); 6.96-

7.00 (m, 3H, H^ar); 7.11-7.24 (m, 9H, H^ar); 7.32 (d, J = 8.0 Hz, 2H,

H^ar); 7.47-7.51 (m, 2H, H^ar); 7.53-7.59 (m, 2H, H^ar); 7.65-7.70 (m,

2H, H^ar) ppm. ¹³C NMR (100 MHz, CD₂Cl₂): δ = 21.7 (CH₃); 57.4

132.0 (C, major); 133.6 (CH, major); 134.1 (CH, minor); 134.9 (C, (CH); 62.0 (C); 123.5 (CH); 127.2 (CH); 127.5 (CH); 127.9 (CH,

major); 137.4 (C, major); 162.4 (C, major); 164.4 (CON, major);

174.2 (C=N, major) ppm. Signals of the major and minor isomers

partially overlap and several signals of the carbon atoms of the

minor form are not resolved. HRMS (ESI), m/z: calcd for

C₃₀H₂₃N₃O₅S [M+H]⁺538.1431, found 538.1430.

2 overlapping signals); 128.4 (CH); 129.1 (CH); 129.6 (CH);

129.7 (CH); 130.26 (CH); 130.31 (C); 131.4 (CH); 132.7 (C);

133.3 (C); 134.2 (C); 134.3 (CH); 136.6 (C); 137.9 (C); 143.9

(C); 165.0 (CON); 178.1 (C=N) ppm. HRMS (ESI), m/z: calcd for

C₃₆H₂₆ClN₃O₄S [M+Na]⁺654.1225, found 654.1239.

N-[Cyclopropyl-[rel-(2R,3S)-1-(1,3-dioxoisoindol-2-yl)-3-(4-

nitrophenyl)aziridin-2-yl]methylene]-4-

N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-(4-methylphenyl)-

2-phenylaziridin-2-yl](phenyl)methylene]-4-

methylbenzenesulfonamide (3j). Cream crystals, 0.868 g

(82%), mp 137-138 °C. According to the ¹H NMR spectrum it

exists as a mixture of invertomers in the ratio of 1:0.44. H NMR

methylbenzenesulfonamide (3m). Pale yellow crystals, 0.927 g

(76%), mp 166-168 °C. ¹H NMR (400 MHz, CD₂Cl₂): δ = 2.23 (s,

3H, CH₃); 2.31 (s, 3H, CH₃); 5.43 (s, 1H, CH); 6.88 (d, J = 8.0 Hz,

2H, H^ar); 6.94-6.99 (m, 5H, H^ar); 7.04 (d, J = 8.0 Hz, 2H, H^ar);

7.11-7.25 (m, 5H, H^ar); 7.31 (d, J = 8.0 Hz, 2H, H^ar); 7.46-7.50

(m, 2H, H^ar); 7.52-7.58 (m, 2H, H^ar); 7.64-7.69 (m, 2H, H^ar) ppm.

¹³C NMR (100 MHz, CD₂Cl₂): δ = 21.2 (CH₃); 21.7 (CH₃); 58.4

(CH); 62.0 (C); 123.4 (CH); 127.2 (CH); 127.5 (CH); 127.68

(CH); 127.74 (CH); 128.2 (CH); 129.0 (CH); 129.1 (CH); 129.6

(CH); 130.1 (CH); 130.4 (C); 130.9 (C); 131.5 (CH); 133.7 (C);

1

(400 MHz, CDCl₃): δ = 1.08-1.47 (m, 2H, c-Pr, major, 4H, c-Pr,

minor); 1.59-1.66 (m, 1H, c-Pr, major); 1.88-1.96 (m, 1H, c-Pr,

major); 2.33 (s, 3H, CH₃, major); 2.44 (s, 3H, CH₃, minor); 2.46-

2.53 (m, 1H, c-Pr, minor); 2.86 (d, J = 4.7 Hz, 1H, H², major);

3.07-3.15 (m, 1H, c-Pr, major); 4.11 (d, J = 5.5 Hz, 1H, H³,

minor); 4.63 (d, J = 4.7 Hz, 1H, H³, major); 5.65-5.77 (br, 1H, H²,

minor); 6.93 (d, J = 8.0 Hz, 2H, H^ar, major); 7.25 (d, J = 8.4 Hz,

2H, H^ar, major); 7.31 (d, J = 8.1 Hz, 2H, H^ar, minor); 7.56-7.74 (m, 134.2 (CH); 136.8 (C); 138.0 (C); 138.4 (C); 143.8 (C); 165.1

6H, H^ar, major, 6H, H^ar, minor); 7.83 (d, J = 8.1 Hz, 2H, H^ar,

minor); 8.14 (d, J = 8.6 Hz, 2H, H^ar, minor); 8.23 (d, J = 8.8 Hz,

2H, H^ar, major) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 11.1 (CH₂,

major); 11.9 (CH₂, major); 14.6 (CH₂, minor); 15.9 (CH, minor);

16.4 (CH₂, minor); 19.9 (CH, major); 21.5 (CH₃, major); 21.6

(CH₃, minor); 45.7 (CH, major); 49.2 (CH, major); 50.8 (CH,

minor); 123.1 (CH, major); 123.3 (CH, minor); 123.4 (CH, minor);

123.9 (CH, major); 126.5 (CH, major); 127.0 (CH, minor); 128.1

(CH, major); 129.2 (CH, major); 129.5 (CH, minor); 129.7 (C,

minor); 129.8 (C, major); 131.1 (CH, minor); 133.9 (CH, major);

134.5 (CH, minor); 136.6 (C, minor); 137.8 (C, major); 142.2 (C,

major); 143.2 (C, major); 143.8 (C, minor); 148.0 (C, major);

148.3 (C, minor); 164.0 (CON, major); 165.0 (CON, minor);

175.4 (C=N, minor); 180.0 (C=N, major) ppm. HRMS (ESI), m/z:

calcd for C₂₇H₂₂N₄O₆S [M+H]⁺531.1333, found 531.1350.

(CON); 178.6 (C=N) ppm. HRMS (ESI), m/z: calcd for

C₃₇H₂₉N₃O₄S [M+H]⁺612.1952, found 612.1943.

N-[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-

phenylspiro[aziridine-2,2'-inden]-1'(3'H)-ylidene]-4-

methylbenzenesulfonamide (3n). Yellow crystals, 0.823 g

1

(77%), mp 182 °C. H NMR (400 MHz, CDCl₃): δ = 2.35 (s, 3H,

CH₃); 3.03 (d, J = 18.6 Hz, 1H, CH₂); 3.51 (d, J = 18.6 Hz, 1H,

CH₂); 4.77 (s, 1H, CH); 6.94 (d, J = 8.1 Hz, 2H, H^ar); 7.25-7.29

(m, 2H, H^ar, CHCl₃); 7.34-7.51 (m, 8H, H^ar); 7.57-7.76 (m, 4H,

H^ar); 8.83 (d, J = 8.2 Hz, 1H, H^ar) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 21.5 (CH₃); 33.0 (CH₂); 56.3 (CH); 59.2 (C); 122.7

(CH); 123.1 (CH); 125.9 (CH); 126.2 (CH); 127.6 (CH); 128.1

(CH); 128.5 (CH); 128.6 (CH); 129.1 (CH); 129.7 (C); 130.4

(CH); 132.8 (C); 133.4 (CH); 133.7 (C); 133.8 (CH); 135.2 (CH);

138.5 (C); 142.7 (C); 152.2 (C); 163.9 (CON); 164.3 (CON);

175.2 (C=N) ppm. Phthalimido substituent produces seven of

eight signals (signal δ = 129.7 is broadened) because rotation

around the N–N bond is slowed down. HRMS (ESI), m/z: calcd

for C₃₁H₂₃N₃O₄S [M+H]⁺534.1482, found 534.1491.

N-[[rel-(2R,3S)-3-(4-Chlorophenyl)-1-(1,3-dioxoisoindol-2-

yl)aziridin-2-yl]-2,2-dimethylpropylidene]-4-

methylbenzenesulfonamide (3k). Colorless crystals, 0.215 g

1

(20%), mp 182 °C. H NMR (400 MHz, CDCl₃): δ = 1.37 (s, 9H,

C(CH₃)₃); 2.43 (s, 3H, CH₃); 3.97 (d, J = 5.7 Hz, 1H, CH); 5.73 (d,

J = 5.7 Hz, 1H, CH); 7.22 (d, J = 8.6 Hz, 2H, H^ar); 7.30 (d, J =

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European Journal of Organic Chemistry

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N-[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-phenyl-3',4'-

dihydro-1'H-spiro[aziridine-2,2'-naphthalen]-1'-ylidene]-4-

methylbenzenesulfonamide (3o). Beige crystals, 0.885 g

2-(4-Methylphenyl)-1-[(4-methylphenyl)sulfonyl]-4-phenyl-

1H-imidazole²¹(4d). Heating

4 h at 140 °С, eluent -

CH₂Cl₂/petroleum ether 2:1. Colorless crystals, 0.111 g (57%),

1

(81%), mp 180-181 °C. H NMR (400 MHz, CDCl₃): δ = 1.67-

mp 142-143 °C (lit. 143 °C)²¹. H NMR (400 MHz, CDCl₃): δ =

1.74 (m, 1H, CH₂); 1.80-1.90 (m, 1H, CH₂); 2.29 (s, 3H, CH₃);

2.74-2.82 (m, 1H, CH₂); 3.72-3.82 (m, 1H, CH₂); 5.06 (s, 1H,

CH); 6.84 (d, J = 8.1 Hz, 2H, H^ar); 7.32-7.46 (m, 9H, H^ar); 7.48-

7.51 (m, 2H, H^ar); 7.54-7.59 (m, 3H, H^ar); 8.70 (d, J = 8.0 Hz, 1H,

H^ar) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 21.5 (CH₃); 27.6

(CH₂); 28.6 (CH₂); 55.9 (C); 56.6 (CH); 122.8 (CH); 126.1 (CH);

126.3 (CH); 128.0 (CH); 128.1 (CH); 128.3 (CH); 128.4 (CH);

129.1 (CH); 130.01 (C); 130.03 (C); 133.2 (CH); 133.3 (CH);

133.7 (C); 134.4 (CH); 138.9 (C); 142.4 (C); 145.7 (C); 164.4

(CON); 169.4 (C=N) ppm. HRMS (ESI), m/z: calcd for

C₃₂H₂₅N₃O₄S [M+Na]⁺570.1458, found 570.1445.

2.37 (s, 3H, CH₃); 2.43 (s, 3H, CH₃); 7.14 (d, J = 8.3 Hz, 2H,

H^ar); 7.20 (d, J = 8.0 Hz, 2H, H^ar); 7.27-7.41 (m, 7H, H^ar); 7.81-

7.85 (m, 2H, H^ar); 7.87 (s, 1H, H⁵) ppm.

2-(4-Methoxyphenyl)-1-[(4-methylphenyl)sulfonyl]-4-phenyl-

1H-imidazole²¹(4e). Heating 4 h at 140 °С, eluent - CH₂Cl₂.

Colorless crystals, 0.093 g (46%), mp 115-116 °C (lit. 113-

1

116 °C)²¹. H NMR (400 MHz, CDCl₃): δ = 2.36 (s, 3H, CH₃);

3.88 (s, 3H, OCH₃); 6.91 (d, J = 8.8 Hz, 2H, H^ar); 7.14 (d, J = 8.2

Hz, 2H, H^ar); 7.27-7.34 (m, 3H, H^ar); 7.36-7.45 (m, 4H, H^ar); 7.81-

7.85 (m, 2H, H^ar); 7.87 (s, 1H, H⁵) ppm.

General procedure for the preparation of imidazoles 4a-o: A

solution of the aziridine 3a-o (0.5 mmol (for 3k 0.25 mmol)) in

dry toluene (10 ml) in a sealed vessel was heated at the

indicated temperature. Then the solvent was distilled off in

vacuo and the residue was separated by column

chromatography (eluent indicated in each case).

1-[(4-Nitrophenyl)sulfonyl]-2,4-diphenyl-1H-imidazole

(4f).

Heating 4 h at 140 °С, eluent - CH₂Cl₂. Yellow crystals, 0.097 g

(48%), mp 120-121 °C. ¹H NMR (400 MHz, CDCl₃): δ = 7.33 (t, J

= 7.3 Hz, 1H, H^ar); 7.38-7.48 (m, 6H, H^ar); 7.51-7.59 (m, 3H, H^ar);

7.81-7.85 (m, 2H, H^ar); 7.91 (s, 1H, H⁵); 8.16 (d, J = 8.8 Hz, 2H,

H^ar) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 115.1 (CH); 124.3

(CH); 125.5 (CH); 128.0 (CH); 128.4 (CH); 128.78 (CH); 128.84

(CH); 130.6 (CH); 130.7 (CH); 131.6 (C); 142.1 (C); 142.7 (C);

148.9 (C); 150.9 (C) ppm. HRMS (ESI), m/z: calcd for

C₂₁H₁₅N₃O₄S [M+H]⁺406.0856, found 406.0860.

1-[(4-Methylphenyl)sulfonyl]-2-(4-nitrophenyl)-4-phenyl-1H-

imidazole²¹(4a). Heating 4 h at 140 °С, eluent - CH₂Cl₂. Yellow

crystals, 0.168 g (80%), mp 194 °C (lit. 194.5-197 °C)²¹. ¹H NMR

(400 MHz, CDCl₃): δ = 2.39 (s, 3H, CH₃); 7.19 (d, J = 7.8 Hz, 2H,

H^ar); 7.30-7.44 (m, 5H, H^ar); 7.75 (d, J = 8.7 Hz, 2H, H^ar); 7.82 (d,

J = 7.8 Hz, 2H, H^ar); 7.92 (s, 1H, H⁵); 8.27 (d, J = 8.7 Hz, 2H,

H^ar) ppm.

1-[(4-Chlorophenyl)sulfonyl]-2,4-diphenyl-1H-imidazole (4g).

Heating 4 h at 140 °С, eluent - CH₂Cl₂/petroleum ether 1.5:1.

1

Pale yellow crystals, 0.105 g (53%), mp 125-126 °C. H NMR

(400 MHz, CDCl₃): δ = 7.28-7.35 (m, 5H, H^ar); 7.38-7.43 (m, 4H,

H^ar); 7.45-7.52 (m, 3H, H^ar); 7.82-7.86 (m, 2H, H^ar); 7.90 (s, 1H,

H⁵) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 115.2 (CH); 125.4

(CH); 127.8 (CH); 128.1 (CH); 128.7 (CH); 128.9 (CH); 129.2

(C); 129.4 (CH); 130.2 (CH); 130.7 (CH); 132.0 (C); 135.9 (C);

141.4 (C); 141.5 (C); 148.7 (C) ppm. HRMS (ESI), m/z: calcd for

C₂₁H₁₅ClN₂O₂S [M+H]⁺395.0616, found 395.0623.

2-(4-Chlorophenyl)-1-[(4-methylphenyl)sulfonyl]-4-phenyl-

1H-imidazole (4b). Heating

4

h

at 140 °С, eluent

-

CH₂Cl₂/petroleum ether 1.5:1. Colorless crystals, 0.146 g (71%),

1

mp 135-136 °C. H NMR (400 MHz, CDCl₃): δ = 2.38 (s, 3H,

CH₃); 7.17 (d, J = 8.2 Hz, 2H, H^ar); 7.29-7.46 (m, 9H, H^ar); 7.80-

7.83 (m, 2H, H^ar); 7.89 (s, 1H, H⁵) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 21.6 (CH₃); 115.6 (CH); 125.3 (CH); 127.4 (CH);

127.9 (C); 128.0 (CH); 128.1 (CH); 128.7 (CH); 129.9 (CH);

131.99 (CH); 132.01 (C); 134.6 (C); 136.3 (C); 141.4 (C); 146.1

(C); 147.6 (C) ppm. HRMS (ESI), m/z: calcd for C₂₂H₁₇ClN₂O₂S

[M+H]⁺409.0772, found 409.0779.

2,4-Diphenyl-1-(phenylsulfonyl)-1H-imidazole (4h). Heating 4

h at 140 °С, eluent - CH₂Cl₂/petroleum ether 1.5:1. Colorless

crystals, 0.104 g (58%), mp 92-93 °C. ¹H NMR (400 MHz,

CDCl₃): δ = 7.29-7.50 (m, 12H, H^ar); 7.52-7.57 (m, 1H, H^ar); 7.83-

7.87 (m, 2H, H^ar); 7.93 (s, 1H, H⁵) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 115.4 (CH); 125.4 (CH); 127.5 (CH); 127.7 (CH);

128.0 (CH); 128.7 (CH); 129.1 (CH); 129.3 (C); 130.0 (CH);

130.7 (CH); 132.1 (C); 134.4 (CH); 137.6 (C); 141.2 (C); 148.8

(C) ppm. HRMS (ESI), m/z: calcd for C₂₁H₁₆N₂O₂S [M+H]⁺

361.1005, found 361.1005.

1-[(4-Methylphenyl)sulfonyl]-2,4-diphenyl-1H-imidazole²¹

(4c). Heating 4 h at 140 °С, eluent - CH₂Cl₂/petroleum ether

1.5:1. Colorless crystals, 0.116 g (62%), mp 129-130 °C (lit. 127

1

-129.5 °C)²¹. H NMR (400 MHz, CDCl₃): δ = 2.36 (s, 3H, CH₃);

7.12 (d, J = 8.2 Hz, 2H, H^m(p-Tol)); 7.28-7.33 (m, 3H, H^o(p-Tol), H^p(4-

^Ph)); 7.36-7.42 (m, 4H, H^m(4-Ph), H^m(2-Ph)); 7.45-7.50 (m, 3H, H^o,p(2-

^Ph)); 7.82-7.86 (m, 2H, H^o(4-Ph)); 7.91 (s, 1H, H⁵) ppm. ¹³C NMR

(100 MHz, CDCl₃): δ = 21.6 (CH₃); 115.4 (C⁵); 125.3 (C^o(4-Ph));

127.5 (C^o(p-Tol)); 127.7 (C^m(4-Ph)); 127.9 (C^p(4-Ph)); 128.7 (C^m(2-Ph));

129.4 (C^i(2-Ph)); 129.7 (C^m(p-Tol)); 130.0 (C^p(2-Ph)); 130.7 (C^o(2-Ph));

132.2 (C^i(4-Ph)); 134.6 (C^i(p-Tol)); 141.1 (C⁴); 145.8 (C^p(p-Tol)); 148.7

(C²) ppm. ¹⁵N NMR (¹H-¹⁵N HMBC, CDCl₃): δ = 207.6 (N¹);

271.5 (N³) ppm. The assignment of signals was performed using

2D NMR including ¹H-¹H COSY, ¹H-¹³C HSQC, HMBC spectra.

1-[(4-Methoxyphenyl)sulfonyl]-2,4-diphenyl-1H-imidazole²¹

(4i). Heating 4 h at 140 °С, eluent - CH₂Cl₂/petroleum ether 3:1.

Colorless crystals, 0.107 g (55%), mp 110-111 °C (lit. 107.5-

110 °C)²¹. ¹H NMR (400 MHz, CDCl₃): δ = 3.81 (s, 3H, OCH₃);

6.74-6.78 (m, 2H, H^ar); 7.28-7.42 (m, 7H, H^ar); 7.45-7.50 (m, 3H,

H^ar); 7.82-7.86 (m, 2H, H^ar); 7.90 (s, 1H, H⁵) ppm.

4-Cyclopropyl-1-[(4-methylphenyl)sulfonyl]-2-(4-

nitrophenyl)-1H-imidazole (4j). Heating 6 h at 140 °С, eluent -

10.1002/ejoc.201701806

European Journal of Organic Chemistry

FULL PAPER

CH₂Cl₂. Pale yellow crystals, 0.128 g (67%), mp 155 °C. ¹H

NMR (400 MHz, CDCl₃): δ = 0.76-0.82 (m, 2H, c-Pr); 0.86-0.92

(m, 2H, c-Pr); 1.80-1.87 (m, 1H, c-Pr); 2.39 (s, 3H, CH₃); 7.19 (d,

assignment of signals was performed using NOESY spectra. ¹³C

NMR (100 MHz, CDCl₃): δ = 21.6 (CH₃); 32.1 (CH₂); 118.5 (CH);

125.17 (CH); 125.19 (CH); 127.2 (CH, 2 overlapping signals);

J = 8.1 Hz, 2H, H^ar); 7.31-7.36 (m, 3H, H^ar, H⁵); 7.62-7.67 (m, 2H, 127.7 (CH); 129.7 (CH); 129.9 (C); 130.0 (CH); 130.8 (CH);

H^ar); 8.19-8.24 (m, 2H, H^ar) ppm. ¹³C NMR (100 MHz, CDCl₃): δ

= 7.2 (CH₂); 8.6 (CH); 21.7 (CH₃); 116.1 (CH); 122.8 (CH); 127.1

(CH); 130.0 (CH); 131.5 (CH); 134.7 (C); 135.8 (C); 145.2 (C);

145.6 (C); 146.2 (C); 148.4 (C) ppm. HRMS (ESI), m/z: calcd for

C₁₉H₁₇N₃O₄S [M+H]⁺384.1013, found 384.1020.

134.8 (C); 135.6 (C); 137.5 (C); 143.3 (C); 145.9 (C); 147.1 (C);

152.2 (C) ppm. HRMS (ESI), m/z: calcd for C₂₃H₁₈N₂O₂S [M+H]⁺

387.1162, found 387.1162.

3-[(4-Methylphenyl)sulfonyl]-2-phenyl-3,8-

dihydroindeno[1,2-d]imidazole (4n'). Cream crystals, 0.098 g

(51%) heating 12 h at 120 °С, mp 116-117 °C. Eluent - CH₂Cl₂

4-(tert-Butyl)-2-(4-chlorophenyl)-1-[(4-

methylphenyl)sulfonyl]-1H-imidazole (4k). Heating 4 h at

and then petroleum ether/EtOAc 3:1 (repeated chromatography)

1

140 °С, eluent - CH₂Cl₂/petroleum ether 1.5:1. Colorless crystals, for the separation 4n/4n' mixture. H NMR (400 MHz, CDCl₃): δ

1

0.070 g (72%), mp 146-147 °C. H NMR (400 MHz, CDCl₃): δ =

1.28 (s, 9H, C(CH₃)₃); 2.38 (s, 3H, CH₃); 7.17 (d, J = 8.2 Hz, 2H,

H^ar); 7.28 (s, 1H, H⁵); 7.29-7.36 (m, 6H, H^ar) ppm. ¹³C NMR (100

MHz, CDCl₃): δ = 21.6 (CH₃); 29.5 (C(CH₃)₃); 31.9 (C(CH₃)₃);

114.1 (CH); 127.3 (CH); 127.9 (CH); 128.4 (C); 129.7 (CH);

132.0 (CH); 135.0 (C); 136.0 (C); 145.7 (C); 146.7 (C); 152.2 (C)

ppm. HRMS (ESI), m/z: calcd for C₂₀H₂₁ClN₂O₂S [M+H]⁺

389.1085, found 389.1082.

= 2.34 (s, 3H, CH₃); 3.60 (s, 2H, CH₂); 7.09 (d, J = 8.3 Hz, 2H,

H^m(p-Tol)); 7.24-7.30 (m, 1H, H⁶, CHCl₃); 7.33 (d, J = 8.3 Hz, 2H,

H^o(p-Tol)); 7.38-7.45 (m, 3H, H^Ph, H⁵); 7.46-7.54 (m, 4H, H^Ph, H⁷);

8.26 (d, J = 7.8 Hz, 1H, H⁴) ppm. The assignment of signals was

performed using NOESY spectra. ¹³C NMR (100 MHz, CDCl₃): δ

= 21.6 (CH₃); 30.6 (CH₂); 120.7 (CH); 125.3 (CH); 125.4 (CH);

127.1 (CH); 127.4 (CH); 127.5 (CH); 129.7 (CH); 129.9 (CH);

130.2 (C); 130.8 (CH); 133.4 (C); 135.3 (C); 136.2 (C); 144.8

(C); 145.6 (C); 150.3 (C); 153.0 (C) ppm. HRMS (ESI), m/z:

calcd for C₂₃H₁₈N₂O₂S [M+H]⁺387.1162, found 387.1174.

2-(4-Chlorophenyl)-1-[(4-methylphenyl)sulfonyl]-4,5-

diphenyl-1H-imidazole (4l). Heating 3 h at 110 °С, eluent -

CH₂Cl₂. Colorless crystals, 0.189 g (78%), mp 181-182 °C. H

1

3-[(4-Methylphenyl)sulfonyl]-2-phenyl-4,5-dihydro-3H-

NMR (400 MHz, CDCl₃): δ = 2.37 (s, 3H, CH₃); 7.06-7.11 (m, 4H, naphtho[1,2-d]imidazole (4o). Heating 12 h at 120 °С, eluent -

H^ar); 7.13-7.18 (m, 3H, H^ar); 7.22-7.26 (m, 2H, H^ar, CHCl₃); 7.33-

7.39 (m, 4H, H^ar); 7.42-7.48 (m, 3H, H^ar); 7.67-7.71 (m, 2H, H^ar)

ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 21.6 (CH₃); 127.3 (CH);

127.45 (CH); 127.51 (CH); 127.9 (CH); 128.0 (CH); 128.1 (CH);

129.1 (CH); 129.3 (C); 129.49 (CH); 129.52 (C); 130.0 (C);

131.8 (CH); 132.0 (CH); 132.5 (C); 135.3 (C); 136.0 (C); 139.5

(C); 145.5 (C); 149.4 (C) ppm. HRMS (ESI), m/z: calcd for

C₂₈H₂₁ClN₂O₂S [M+H]⁺485.1085, found 485.1098.

CH₂Cl₂. Cream crystals, 0.088 g (44%), mp 109-110 °C. ¹H NMR

(400 MHz, CDCl₃): δ = 2.38 (s, 3H, CH₃); 3.11 (t, J = 8.0 Hz, 2H,

H⁵); 3.31 (t, J = 8.0 Hz, 2H, H⁴); 7.14-7.26 (m, 5H, H^m(p-Tol), H^6,7,8

,

CHCl₃); 7.34 (d, J = 8.4 Hz, 2H, H^o(p-Tol)); 7.38-7.43 (m, 2H, H^Ph);

7.46-7.51 (m, 3H, H^Ph); 7.78 (d, J = 7.4 Hz, 1H, H⁹) ppm. The

assignment of signals was performed using NOESY spectra. ¹³

C

NMR (100 MHz, CDCl₃): δ = 21.6 (CH₃); 22.2 (CH₂); 28.9 (CH₂);

121.7 (CH); 126.9 (CH); 127.1 (CH, 2 overlapping signals);

127.55 (CH); 127.63 (CH); 128.6 (C); 129.76 (CH); 129.80 (CH);

130.1 (C); 130.6 (C); 130.9 (CH); 133.7 (C); 135.6 (C); 137.6

(C); 145.6 (C); 149.9 (C) ppm. HRMS (ESI), m/z: calcd for

C₂₄H₂₀N₂O₂S [M+H]⁺401.1318, found 401.1331.

2-(4-Methylphenyl)-1-[(4-methylphenyl)sulfonyl]-4,5-

diphenyl-1H-imidazole (4m). Heating 3 h at 110 °С, eluent -

1

CH₂Cl₂. Colorless crystals, 0.170 g (73%), mp 180-181 °C. H

NMR (400 MHz, CDCl₃): δ = 2.36 (s, 3H, CH₃); 2.45 (s, 3H,

CH₃); 7.06-7.11 (m, 4H, H^ar); 7.13-7.18 (m, 3H, H^ar); 7.24-7.30

(m, 4H, H^ar, CHCl₃); 7.33-7.40 (m, 4H, H^ar); 7.41-7.46 (m, 1H,

H^ar); 7.63 (d, J = 8.1 Hz, 2H, H^ar) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 21.5 (CH₃); 21.6 (CH₃); 127.3 (CH); 127.4 (CH);

127.5 (CH); 128.0 (CH); 128.1 (CH); 128.3 (CH); 128.7 (C);

128.9 (C, CH); 129.4 (CH); 129.9 (C); 130.4 (CH); 132.0 (CH);

132.8 (C); 135.5 (C); 139.2 (C); 139.8 (C); 145.2 (C); 150.8 (C)

ppm. HRMS (ESI), m/z: calcd for C₂₉H₂₄N₂O₂S [M+H]⁺465.1631,

found 465.1645.

Isomerization imidazole 4n' into 4n: A solution of the

imidazole 4n' (39 mg, 0.1 mmol) in dry toluene (2 ml) in a sealed

vessel was heated at 150 °С for 4h. Then the solvent was

evaporated and the residue was purified by column

chromatography (petroleum ether/EtOAc 3:1) on silica to provide

imidazole 4n in 49% yield (19 mg).

Synthesis of ¹⁵N-labeled compounds: ¹⁵NH₂OH•HCl (Berlin-

Chemie, 95% purity, 96.7% enrichment) was used. ¹⁵N-(2E)-1,3-

diphenylprop-2-en-1-one

oxime

(5)

and

¹⁵N-((2E)-1,3-

1-[(4-Methylphenyl)sulfonyl]-2-phenyl-1,8-

Diphenylprop-2-en-1-ylidene)-4-methyl-benzenesulfonamide

(2c-¹⁵N) were prepared according to the reported procedures^28,34

for unlabeled compounds with minor changes. Compounds 3c-

¹⁵N and 4c-¹⁵N were synthesized as described in general

procedures for unlabeled compounds 3c,4c.

dihydroindeno[1,2-d]imidazole (4n). Cream crystals, 0.012 g

(6%) heating 12 h at 120 °С, 0.062 g (32%) heating 6 h at

150 °С, mp 162-163 °C. Eluent - CH₂Cl₂and then petroleum

ether/EtOAc 3:1 (repeated chromatography) for the separation

4n/4n' mixture. ¹H NMR (400 MHz, CDCl₃): δ = 2.35 (s, 3H,

CH₃); 4.01 (s, 2H, CH₂); 7.10 (d, J = 8.1 Hz, 2H, H^m(p-Tol)); 7.22-

7.30 (m, 3H, H^o(p-Tol), H⁶, CHCl₃); 7.32-7.43 (m, 3H, H^Ph, H⁵);

7.46-7.53 (m, 4H, H^Ph, H⁷); 7.66 (d, J = 7.4 Hz, 1H, H⁴) ppm. The

Synthesis of ¹⁵N-(2E)-1,3-diphenylprop-2-en-1-one oxime (5):

To a solution of (E)-1,3-diphenylprop-2-en-1-one (2.083 g, 10

mmol) in methanol (20 mL) was added ¹⁵NH₂OH•HCl (1.058 g,

10.1002/ejoc.201701806

European Journal of Organic Chemistry

FULL PAPER

15 mmol) and pyridine (1.978 g, 2.0 mL, 25 mmol). The reaction

mixture was stirred at room temperature for 24 h. The solvent

was evaporated and the residue was diluted with CH₂Cl₂(30

mL) and water (30 mL). The aqueous layer was extracted with

CH₂Cl₂(2×15 mL). The combined organic layers were

sequentially washed with 1 N HCl, saturated aqueous NaHCO₃

and brine, dried over Na₂SO₄. After evaporation of the solvent,

¹⁵N-[[rel-(2R,3S)-1-(1,3-Dioxoisoindol-2-yl)-3-phenylaziridin-

2-yl](phenyl)methylene]-4-methylbenzenesulfonamide (3c-

¹⁵N). Cream crystals, 0.792 g (76%), mp 170-171 °C. According

1

to the H NMR spectrum it exists as a mixture of invertomers in

1

the ratio of 1:0.21. H NMR (400 MHz, CDCl₃): δ = 2.25 (s, 3H,

CH₃, major); 2.42 (s, 3H, CH₃, minor); 3.83 (t, J = 4.6 Hz, 1H, H²,

major); 4.08 (d, J = 5.5 Hz, 1H, H³, minor); 4.78 (d, J = 4.8 Hz,

1H, H³, major); 5.72-6.08 (br, 1H, H², minor); 6.81 (d, J = 8.1 Hz,

2H, H^ar, major); 7.23-7.26 (m, 3H, H^ar, minor, CHCl₃); 7.29-7.42

(m, 5H, H^ar, major, 4H, H^ar, minor); 7.44-7.69 (m, 9H, H^ar, major,

7H, H^ar, minor); 7.89 (d, J = 8.2 Hz, 2H, H^ar, minor); 8.01-8.10 (m,

2H, H^ar, major, 2H, H^ar, minor) ppm. ¹³C NMR (100 MHz, CDCl₃):

δ = 21.5 (CH₃); 52.56 (CH, major); 52.63 (CH, major); 52.9 (CH,

minor); 123.0 (CH, major); 123.1 (CH, minor); 126.8 (CH, major);

127.2 (CH, major); 127.3 (CH, minor); 128.18 (CH, minor);

the residue was subjected to

a

flash chromatography

(hexane/EtOAc 6:1) giving the corresponding oxime.

¹⁵N-(2E)-1,3-diphenylprop-2-en-1-one oxime (5). Colorless

1

crystals, 1.742 g (78%), mp 89-90 °C. According to the H NMR

spectrum, it exists as a mixture of E/Z isomers about the C=N

bond in the ratio 1:0.5. According to the literature³⁵coupling

constants ³J (N,H) and ²J (N,C) are larger for the isomer with cis-

oriented nitrogen lone pair and corresponding carbon substituent, 128.20 (CH, minor); 128.3 (CH, major); 128.65 (CH, major);

therefore isomer with (Е)-configuration of the C=N bond is the

major one. H NMR (400 MHz, CDCl₃): δ = 6.52 (d, J = 16.3 Hz,

128.69 (CH, major); 128.97 (CH, major); 129.04 (CH, major);

129.2 (CH, minor); 129.4 (CH, minor); 129.7 (C, minor); 129.9 (C,

major); 130.0 (CH, minor); 131.9 (CH, major); 133.5 (CH, major);

134.1 (CH, minor); 134.9 (C, major); 135.4 (C, minor); 137.4 (d,

J = 1.5 Hz, C, major); 137.5 (d, J = 7.8 Hz, C, major); 142.9 (C,

major); 143.7 (C, minor); 164.3 (CON, major); 174.7 (d, J = 4.6

Hz, C=N, major) ppm. Signals of the major and minor isomers

partially overlap. ¹⁵N NMR (40.5 MHz, CDCl₃): δ = 317.1 ppm.

HRMS (ESI), m/z: calcd for C₃₀H₂₃N₂¹⁵NO₄S [M+H]⁺523.1452,

found 523.1463.

1

1H, H³, minor); 6.84 (d, J = 16.6 Hz, 1H, H³, major); 7.11 (dd, J =

16.3 Hz, 2.3 Hz, 1H, H², minor); 7.28-7.57 (m, 10H, H^ar, major,

10H, H^ar, minor); 7.72 (dd, J = 16.6 Hz, 1.0 Hz, 1H, H², major);

8.36-10.02 (br, 1H, OH, major, 1H, OH, minor) ppm. ¹³C NMR

(100 MHz, CDCl₃): δ = 117.1 (d, J = 1.7 Hz, C², major); 125.7 (d,

J = 12.1 Hz, C², minor); 126.9 (CH, minor); 127.5 (CH, major);

128.3 (CH); 128.4 (CH, major); 128.6 (CH); 128.68 (CH); 128.72

(CH, major); 128.9 (CH, minor); 129.2 (CH, major, minor); 131.5

(d, J = 1.2 Hz, C, minor); 134.7 (d, J = 8.9 Hz, C, major); 136.1

(C, major, minor); 137.0 (d, J = 5.9 Hz, C³, minor); 139.7 (d, J =

2.7 Hz, C³, major); 157.7 (d, J = 3.6 Hz, C=N, major); 159.2 (d, J

= 4.1 Hz, C=N, minor) ppm. ¹⁵N NMR (40.5 MHz, CDCl₃): δ =

348.6 (major); 354.2 (minor) ppm. HRMS (ESI), m/z: calcd for

C₁₅H₁₃¹⁵NO [M+H]⁺225.1040, found 225.1047.

(3-¹⁵N)-1-[(4-Methylphenyl)sulfonyl]-2,4-diphenyl-1H-

imidazole (4c-¹⁵N). Colorless crystals, 0.114 g (61%), mp

1

130 °C. H NMR (400 MHz, CDCl₃): δ = 2.36 (s, 3H, CH₃); 7.12

(d, J = 8.1 Hz, 2H, H^m(p-Tol)); 7.28-7.33 (m, 3H, H^o(p-Tol), H^p(4-Ph));

7.36-7.42 (m, 4H, H^m(4-Ph), H^m(2-Ph)); 7.45-7.50 (m, 3H, H^o,p(2-Ph));

7.82-7.86 (m, 2H, H^o(4-Ph)); 7.91 (d, J = 0.8 Hz, 1H, H⁵) ppm. ¹³

C

Synthesis of ¹⁵N-[(2E)-1,3-Diphenylprop-2-en-1-ylidene]-4-

methylbenzenesulfonamide (2c-¹⁵N). A solution of oxime 5

(1.12 g, 5.0 mmol) in dry CH₂Cl₂(20 mL) was treated

sequentially with triethylamine (0.606 g, 0.83 mL, 6.0 mmol) and

p-toluenesulfinyl chloride (0.960 g, 5.5 mmol) at 0°C and the

resulting mixture was stirred for 30 min, warmed to room

temperature and stirred for 12 h. The reaction mixture was

washed with water and brine, dried over Na₂SO₄, filtered, and

concentrated in vacuo. The residue was purified by flash

NMR (100 MHz, CDCl₃): δ = 21.6 (CH₃); 115.4 (d, J = 1.2 Hz,

C⁵); 125.4 (d, J = 1.9 Hz, C^o(4-Ph)); 127.5 (C^o(p-Tol)); 127.7 (C^m(4-

^Ph)); 127.9 (C^p(4-Ph)); 128.7 (C^m(2-Ph)); 129.5 (d, J = 5.9 Hz, C^i(2-Ph));

129.7 (C^m(p-Tol)); 130.0 (C^p(2-Ph)); 130.7 (br, C^o(2-Ph)); 132.2 (d, J =

5.9 Hz, C^i(4-Ph)); 134.6 (C^i(p-Tol)); 141.1 (br, C⁴); 145.8 (C^p(p-Tol));

148.7 (d, J = 1.9 Hz, C²) ppm. ¹⁵N NMR (40.5 MHz, CDCl₃): δ =

271.6 ppm. HRMS (ESI), m/z: calcd for C₂₂H₁₈N¹⁵NO₂S [M+H]⁺

376.1132, found 376.1144.

chromatography on silica gel (hexane/EtOAc 8:1) to afford imine. X-Ray diffraction data:

A

single-crystal X-ray diffraction

experiments were carried out using Agilent Technologies

«Xcalibur» and «SuperNova» diffractometers with

¹⁵N-[(2E)-1,3-Diphenylprop-2-en-1-ylidene]-4-

methylbenzenesulfonamide (2c-¹⁵N). Beige crystals, 1.071 g

(59%), mp 151-152 °C. H NMR (400 MHz, CDCl₃): δ = 2.42 (s,

monochromated MoKα and CuKα radiation. The crystals were

kept at 100(2) K during all data collection. The structures had

been solved by the Superflip³⁶and ShelXS³⁷structure solution

programs using Charge Flipping and Direct Methods,

respectively, and refined by means of the ShelXL³⁸program,

incorporated in the OLEX2 program package³⁹. CCDC 1579970-

1

3H, CH₃); 7.07 (d, J = 16.0 Hz, 1H, H³); 7.31 (d, J = 8.1 Hz, 2H,

H^ar); 7.38-7.47 (m, 5H, H^ar); 7.52-7.70 (m, 5H, H^ar); 7.93 (d, J =

7.4 Hz, 2H, H^ar); 8.00-8.22 (br, 1H, H²) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 21.5 (CH₃); 122.6 (CH, br); 127.2 (CH); 128.3 (CH);

128.7 (CH); 129.0 (CH); 129.4 (CH); 130.1 (CH, br); 131.1 (CH);

131.8 (CH, br); 134.5 (C); 138.7 (d, J = 6.8 Hz, C); 143.4 (C);

148.8 (CH); 177.5 (C=N, br) ppm. ¹⁵N NMR (40.5 MHz, CDCl₃):

δ = 308.5 ppm. HRMS (ESI), m/z: calcd for C₂₂H₁₉¹⁵NO₂S

[M+H]⁺363.1180, found 363.1190.

1579975 for compounds 2l,2l',3f,3m,3o,4k

contains the

supplementary crystallographic data for this paper. These data

can be obtained free of charge from the Cambridge

Crystallographic Data Centre.

10.1002/ejoc.201701806

European Journal of Organic Chemistry

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Acknowledgements

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Article Doi

Thermal Ring Expansion of 2-Sulfonylimidoyl-1-phthalimidoaziridines into N-Sulfonylimidazoles

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