Reaction of potassium 2-(1-adamantyl)ethynethiolate with nitrilimines

Full text of DOI:10.1134/S1070428011110248

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 11, pp. 1777−1780. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © M.L. Petrov, A.A. Shchipalkin, V.A. Kuznetsov, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47, No. 11, pp. 1737−1739.
SHORT
COMMUNICATIONS
Reaction of Potassium 2-(1-Adamantyl)ethynethiolate
with Nitrilimines
M. L. Petrov, A. A. Shchipalkin, and V. A. Kuznetsov
St. Petersburg State Technological Institute, St. Petersburg,190013 Russia
e-mail: mlpetrov@lti-gti.ru
Received April 13, 2011
DOI: 10.1134/S1070428011110248
Nitrilimines are the most active donor Huisgen
1,3-dipoles that readily are brought into the
[2+3]-cycloaddition reactions with thiocarbonyl
compounds. The simplest method of nitrilimines
generation is the reaction of hydrazonoyl chlorides with
bases [1]. It was formerly established that potassium
2-arylethynethiolates form with nitrilimines products
of [2+3]-cycloaddition, 1,3,4-thiadiazolines [2]. It was
proved that this reaction could proceed both as a concerted
1,3-dipolar cycloaddition and in two stages. First a linear
product formed resulting from the nucleophilic attack of
the thiolate on the electrophilic site of the nitrilimine
that at the treatment with a methanol solution of KOH
quantitatively converted into thiadiazolidine. The
reaction of potassium 2-arylethynethiolates with the
initial compounds for nitrilimines synthesis (hydrazonoyl
chlorides) occurred exclusively as the nucleophilic
substitution of the halogen by the thiolate residue [2].
At the same time the reaction of potassium 2-tert-
butylethynethiolate with nitrilimines afforded only the
linear product of the nucleophilic attack of the thiolate
on the electrophilic site of the nitrilimine. This product
did not undergo the intramolecular cyclization under the
treatment with bases evidently due to the geometry of
the molecule [3].
(II) with hydrazonoyl chlorides IIIa, IIIb containing
strond electron-withdrawing substituents MeC=O (IIIa)
and CO2Me (IIIb) takes two routes. The first direction
consists in the nucleophilic substitution of the halogen in
hydrazonoyl chlorides IIIa, IIIb by thiolate II.
t-BuOK
_ N2
_
S K+
N
N
S
I
II
R
H
Cl
N N Ar
R
IIIа, IIIb
H
N
S
N
Ar
_ KCl
IVа, IVb
R = Ac, Ar = Ph (a); R = CO2Me, Ar = 4-ClC6H4 (b).
The structure of isolated products of the
nucleophilic substitution 1-(1-adamantylethynethio)-
1-phenylhydrazono-2-oxopropane (IVa) and methyl
(1-adamantylethynethio)[(4-chlorophenyl)hydrazono]
acetate (IVb) was proved by the IR, 1H, 13C NMR, and
mass spectra. The IR spectra of hydrazones IVa, IVb
contain the absorption bands of the stretching vibrations
of the NH bonds in the region 3195 (IVa) and 3245 (IVb)
cm–1, no absorption bands of the stretching vibrations of
the triple bonds, strong bands of the stretching vibrations
of C=O [1708 (IVa), 1688 (IVb)] and C=N bonds [1520
Potassium 2-(1-adamantyl)ethynethiolate (II) obtained
by the treatment with such a strong base as potassium
tert-butylate of 4-(1-adamantyl)-1,2,3-thiadiazole (I)
[4] readily reacted with hydrazonoyl chlorides IIIa–IIIc.
However the direction of the reaction is ambiguous
and depends on the character of the substituents in
hydrazonoyl chlorides IIIa–IIIc. For instance, the
reaction of potassium 2-(1-adamantyl)-ethynethiolate
1
(IVa), 1527 (IVb) cm–1]. In the H NMR spectra the
signals of amine protons are present at δNH 10.53 (IVa)
and 9.12 (IVb) ppm. The 13C NMR spectra contain the
1777

PETROV et al.
1778
signals of the carbon atoms of the triple bond SC≡ [61.22
(IVa), 59.45 (IVb)] and ≡C–C [103.3 (IVa), 107.1 (IVb)
ppm]. In the mass spectra of hydrazones IVa, IVb fairly
intensive peaks of molecular ions were observed.
of the stretching vibrations of NH bond and contains the
characteristic bands of the stretching vibrations of CH=C
bonds (3051 cm–1). In the 1H NMR spectrum the signal of
amine proton is absent, the signal of the methylene proton
appears at δCH=C 7.26 ppm. The 13C NMR spectrum
lacks the signals of the carbon atoms of triple bonds and
contains the signals of the methine carbon atom C=CH
(110.44 ppm) and atoms C5 (127.31) and C2 (155.88
ppm) of the heterocycle. A weak peak of the molecular
ion is detected in the mass. The structure of the isolated
thiadiazoline IX is confirmed by further fragmentation of
the molecular ion. In contrast to hydrazones IVa, IVb the
heterocyclic ring of compound IX is sufficiently stable,
and the decomposition of adamantyl radical known by
publications occurs with the ejection of C4H9 radical [7].
The chromatographic separation of the reaction mix-
tures showed that alongside the formation of the products
of nucleophilic substitution a second route of the reaction
led to the formation of nitrilimine VI from hydrazonoyl
chloride IVa. Here potassium 2-(1-adamantyl)ethynethi-
olate (II) played the role of a base. From this reaction
“dimers” of thiolate (II) [2-(1-adamantyl)-methylene-
4-(1-adamantyl)-2H-dithiol (VII)] and of nitrilimine
VI [3,6-diacetyl-1,4-diphenyl-1H,4H-1,2,4,5-tetrazine
(VIII)] were obtained.
The structure of tetrazine VIII and dithiol VII was
proved by the comparison with the previously obtained
samples [5, 6].
The obtained results of the study of the reaction
between potassium 2-(1-adamantyl)ethynethiolate (II)
and hydrazonoyl chlorides IIIa–IIIc and comparison
with the published data on similar reactions with tert-
butyl-substituted ethynethiolates [2, 3] show an essential
difference in the effect on these reactions of the adamantyl
and tert-butyl residues.
_
+
Ac C N N Ph
IIIa
+
II
SH
+
_KCl
VI
V
1-(Adamantan-1-ylethynylsulfanyl)-1-(N1-phenyl-
hydrazono)propan-2-one (IVa). To a solution of 0.5 g
(2.2 mmol) of thiadiazole I in 25 ml of anhydrous THF
was added 0.26 g (2.4 mmol) of potassium tert-butylate
under an argon atmosphere at room temperature. The reac-
tion mixture was stirred for 5 min till complete end of gas
liberation; therewith a precipitate of potassium thiolate
II separated from the reaction mixture. Then 0.43 g (2.2
mmol) of hydrazonoyl chloride IIIa was added. The reac-
tion mixture was stirred for 3 h, the solvent was distilled
off in a vacuum. The precipitate was washed with water,
dried, dissolved in 20 ml of chloroform, and boiled with
5 g of silica gel for 0.5 h, the solvent was distilled off in a
vacuum. The residue was crystallized from ethanol. Yield
0.1 g (13%). Colorless crystals, mp 154–155°C, Rf 0.45
(ethyl acetate–hexane, 1:8). IR spectrum, ν, cm–1: 3195,
2927, 2901, 2892, 2848, 1708, 1597, 1520, 1471, 1435,
II
Ph
Ac
N
S
S
N
N
N
Ac
Ph
VII
VIII
The change of the character of substituent to the
electron-donor phenyl resulted in the reaction of
[2+3]-cycloaddition of potassium 2-(1-adamantyl)
ethynethiolate (II) to hydrazonoylchloride IIIc. Thus
2-(1-adamantyl)methylene-3,5-diphenyl-2H-1,3,4-
thiadiazoline (IX) was obtained.
Ph
1
1245, 1185, 1065, 821, 756. H NMR spectrum (DMSO-
Ph
Cl
N
N Ph
d6), δ, ppm: 1.56 m (6HAd), 1.72 m (6HAd), 1.83 m (3HAd),
2.43 s (3H, CH3CO), 7.03 d (H4Ph, J 7 Hz), 7.34 t (H3,
H5Ph, J 7.5 Hz), 7.46 t (H2, H6Ph, J 7 Hz), 10.53 s (NH).
13C NMR spectrum (DMSO-d6), δ, ppm: 25.31 (CH3),
27.21 (CHAd), 30.47 (C1Ad), 35.60, 41.96 (CH2Ad), 61.22
(SC≡C), 103.30 (SC≡C), 115.06 (C2,6Ph), 123.09 (C 4Ph),
126.78 (SC=N), 129.30 (C3,5Ph), 142.44 (C1Ph), 191.64
(C=O). Mass spectrum, m/z (Irel, %): 352 (12) [M]+, 135
N N
S
IIIc
II
Ph
IX
The structure of 2-(1-adamantyl)methylene-3,5-
diphenyl-2H-1,3,4-thiadiazoline (IX) was proved with IR,
1H, 13C, and mass spectra. Its IR spectrum lacks the band
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 11 2011

REACTION OF POTASSIUM 2-(1-ADAMANTYL)ETHYNETHIOLATE
1779
(74) [Ad]+, 92 (100), 77 (21) [Ph]+, 65 (45), 51 (9), 43
(75) [CH3CO]. Found, %: C 71.38, 71.25; H 6.55, 6.72.
C21H24N2OS. Calculated, %: C 71.56; H 6.86. M 352.49.
butylate, and 0.5 g (2.2 mmol) of the corresponding
hydrazonoyl chloride IIIc. The precipitate was dissolved
in 20 ml of chloroform, and boiled with 3 g of silica
gel for 0.5 h, the solvent was distilled off in a vacuum.
The residue was crystallized from ethanol. Yield 0.36 g
(41%). Yellow-orange needle crystals, mp 210– 211°C,
Rf 0.6 (ethyl acetate–hexane, 1:8). IR spectrum, ν, cm–1:
3051, 3024, 2929, 2896, 2843, 1538, 1449, 1342, 1296,
3,6-Diacetyl-1,4-diphenyl-1H,4H-[1,2,4,5]-tetra-
zine (VIII). The precipitate after the reaction from the
previous experiment was subjected to chromatography on
a column (3 × 20 cm) packed with silica gel L 100/160,
eluent ethyl acetate–hexane, 1:8, the fraction with Rf 0.36
was collected. The solvent was distilled off. Yield 0.15 g
(35%). Red crystals, mp 161–162°C (mp 162–163°C [5]).
1H NMR spectrum (DMSO-d6), δ, ppm: 2.53 s (6H,
CH3CO), 7.13m (4HPh), 7.28 m (6HPh).
1
1225, 1136, 736, 683, 591. H NMR spectrum (CDCl3),
δ, ppm: 1.88 m (6HAd), 2.17 m (3HAd), 2.30 m (6HAd),
7.23 m (H3, H5NPh), 7.26 s (CH=), 7.48 m, 7.93 m (8HAr).
13C NMR spectrum (CDCl3), δ, ppm: 28.66 (CHAd), 33.48
(C1Ad), 36.81, 42.60 (CH2Ad), 110.44 (C=CH), 112.70
(C2Ht), 119.91 + 120.25 (C2,6Ph), 126.46 (C4N–Ph), 127.31
(C1=C–Ph), 127.74 (C1N–Ph), 128.76 (C4=C–Ph), 130.37 +
130.66 (C3,5Ph), 155.88 (C5Ht). Macc-cпeqtp, m/z (Irel,
%): 386 (7) [M]+, 384 (96) [M – 2]+, 327 (100) [M – 2 –
C4H9]+, 290 (12), 263 (9), 250 (11), 223 (21), 186 (18),
165 (24), 135 (15) [Ad]+, 128 (25), 121 (14 ), 103 (34),
91 (29), 77 (32) [Ph]+, 67 (10), 51 (15), 41 (47). Found,
%: C 77.47, 77.51; H 6.42, 6.81. C25H26N2S. Calculated,
%: C 77.68; H 6.78. M 386.55.
From the fraction with Rf 0.81 on removing the
solvent we obtained 2-(1-adamantyl)methylene-4-(1-
adamantyl)-[1,3]dithiol (VII). Yield 0.15 g (41%).
Colorless crystals, mp 252–255°C (mp 250–255°C [6]).
1H NMR spectrum (DMSO-d6), δ, ppm: 1.80 m (6HAd),
2.02 m (9HAd), 5.11 s (E, H4Ht), 5.15 d (Z, H4 Ht, J 2 Hz),
5.66 d (Z, CH=, J 2 Hz), 5.70 s (E, CH=).
Compounds IVb, IX were similarly obtained.
Methyl (1-adamantylethynylsulfanyl)[(4-chloro-
phenyl)hydrazono]acetate (IVb) was obtained from
0.5 g (2.2 mmol) of thiadiazole I, 0.26 g (2.4 mmol) of
potassium tert-butylate, and 0.54 g (2.2 mmol) of hydra-
zonoyl chloride IIIb. The precipitate was subjected to
chromatography on a column (3 × 20 cm) packed with
silica gel L 100/160, eluent chloroform–hexane, 1 : 10,
the fraction with Rf 0.41 (ethyl acetate–hexane, 1:8) was
collected. The solvent was distilled off. Yield 0.29 g
(33%). Light-yellow needle crystals, mp 153–154°C. IR
spectrum, ν, cm–1: 3245, 2927, 2904, 2849, 1688, 1602,
Melting points were measured on a Boёtius heating
block. IR spectra were recorded on a spectrophotometer
Shimadzu FTIR 84000S from pellets with KBr. 1H and
13C NMR spectra were registered on a spectrometer
Bruker AMX-400 (400 and 100 MHz respectively), the
signals of residual protons (1H) and carbon atoms (13C)
of deuterated solvents served as internal references. Mass
spectra were taken on an instrument Finnigan INCOS
MAT 95 with the direct admission of the sample into
the ion source, ionizing electrons energy 70 eV, ionizing
chamber temperature 200°C. The reaction progress was
monitored by TLC on Silica Gel 60 F254 plates, develop-
ment under UV irradiation or in iodine vapor.All solvents
used in the study were purified and dried by standard
procedures.
1
1527, 1491, 1450, 1235, 1024, 753, 688. H NMR spec-
trum (CDCl3), δ, ppm: 1.63 m (6HAd), 1.78 m ( 6HAd),
1.91 m (3HAd), 3.89 s (3H, CH3O), 7.21 d (H3, H5
,
Ar
J 7 Hz), 7.30 d (H2, H6Ar, J 7 Hz), 9.12 s (NH). 13C NMR
spectrum (CDCl3), δ, ppm: 27.63 (CHAd), 31.07 (C1Ad),
35.02 + 42.28 (CH2Ad), 52.99 (CH3O), 59.45 (SC≡C),
107.1 (SC≡C), 115.64 (C2, C6Ar), 119.2 (C4 Ar), 128.12
(C1Ar), 129.4 (C3, C5Ar), 140.41 (C=N), 162.65 (C=O).
Mass spectrum, m/z (Irel, %): 402 (12) [M]+, 135 (27)
[Ad]+, 126 (100), 111 (18 ), 99 (56), 91 (51), 79 (34), 63
(30), 53 (24), 41 (70). Found, %: C 62.78, 62.87; H 5.43,
5.39. C21H23ClN2O2S. Calculated, %: C 62.60; H 5.75.
M 402.94.
ACKNOWLEDGMENTS
The study was carried out under the financial support
of the Russian Foundation for Basic Research (grant no.
08-03-00383-a).
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