JOURNAL OF CHEMICAL RESEARCH 2014 465
a
c
b
Fig. 1 Molecular structure of compound 5 at 30%probability thermal
ellipsoids.
O
O
O S
O2
N
N
O2 S O
Fig. 3 Packing diagram of 5,5′-dinitro-[5,5′-bi(1,3,2-dioxathiane)]2,2′-
dioxide.
O
O
Fig. 2 Newman projection of compound 5.
In conclusion, we have synthesised a novel 1,3,2-dioxathiane-
2-oxide derivative and its structure was characterised by IR,
1H NMR, 13C NMR and X-ray crystal analysis.
As shown in the Fig. 1, the molecule is made up of two
six-membered heterocyclic rings, which exist in a chair
conformation with the S=O group axially oriented.13,14
This shows that the energy of the title compound with chair
conformation is lower than that of title compound with other
conformations. In the six-membered ring, atoms O3, C2,
O4 and C3 are not in one plane. Two nitro groups exist with
staggered conformation from Newman projection (Fig. 2). In
the molecule, all bond distances are normal, and all C atoms
are of sp3 hybridisation, while the bond angles of C(2)–C(1)–
C(1A), C(3)–C(1)–C(1A) and N(1)–C(1)–C(1A) are different
from 109.5° with the influence of the nitro group (Table 2).
Interestingly, there exists only one kind of H proton in the
methylene of the title compound, while the different chemical
shifts of the two protons in the 1H NMR spectrum can be seen
from Fig. 3. In the analysis of some analogous structures,
according to Takeo Sato and Bi Fu-Qiang,15,16 the difference
exists because of the function of steric configuration, while the
methylene protons experience magnetic nonequivalence.
Apart from this explanation, hydrogen bonds may be used
to explain the different chemical shifts of H atoms of the
methylene. In the methylene, only one H atom participates
hydrogen bond, resulting in the difference of chemical
environment of the two H atoms.
Experimental
All commercial reagents and solvents were purchased and used
without further purification. Melting points were determined using
XT4A microscope melting point apparatus (uncorrected). IR spectra
were recorded on a PerkinElmer FT-IR spectrophotometer with KBr
1
pellets. H and 13C NMR spectra were recorded at a Varian mercury-
plus 400 spectrometer with TMS as the internal standard. Elemental
analyses (C, H and N) were performed on a Flash EA 1112 elemental
analyser.
General procedure
2,3-Bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol 4 (4 mmol) was
dissolved in 6 mL of thionyl chloride. Then pyridine (2 mL) was added
to the solution and the system were refluxed for 4 h. The reaction
mixture was added dropwise to ice water (100 mL) immediately under
magnetic stirring, and white solid was precipitated. After stirring for a
few minutes, the solid was washed with water for several times. Then
filtration gave the product and it was recrystallised from MeOH to
give white crystalline powder. The colourless single crystal suitable
for X-ray diffraction analysis was obtained by diffusion of petroleum
ether when the compound was dissolved in ethyl acetate for a few days.
5,5′-Dinitro-[5,5′-bis(1,3,2-dioxathiane)]2,2′-dioxide (5): Solid,
yield: 75%, m.p. 194 °C; IR (KBr, cm–1): 1568, 1332 (NO2); 1H NMR:
(400 MHz, DMSO-d6) δH 4.88 (d, 4H, J= 12.8 H z, CH 2), 5.44 (d, 4H,
J=13.2 Hz, CH2); 13C NMR: (100 MHz, DMSO-d6) δC 56.77, 87.90.
Anal. calcd for C6H8N2O10S2: C, 21.69; H, 2.43; N, 8.43; found: C, 21.47;
H, 2.45; N, 8.18%.
As shown in Fig. 3, there exists in the crystal lattice two
kinds of potential weak intermolecular interactions of C–H···O,
which are summarised in Table 3, only one H atom of the
methylene participates in the hydrogen bonds.
Crystal structure determination of 5,5′-dinitro-[5,5′-bi(1,3,2-
dioxathiane)]2,2′-dioxide (5): Suitable single crystals of 5 for X-ray
structural analysis were obtained by recrystallisation from petroleum/
ethyl acetate. The diffraction data was collected with a Bruker
SMART CCD diffractometer using a graphite monochromated Mo
Table 2 Selected bond lengths (Å) and bond angles (°)
Bond
Dist.
Bond
Dist.
S(1)–O(4)
S(1)–O(3)
S(1)–O(5)
1.628(5)
1.623(4)
1.444(5)
O(4)–C(3)
O(3)–C(2)
C(1)–C(1A)
1.449(7)
1.444(7)
1.601(12)
Table 3 Hydrogen bond lengths (Å) and bond angles (°)
Angle
(°)
Angle
(°)
D–H…A
d(D–H)
d(H…A)
d(D…A)
∠DHA
C(2)–H(2B)…O(1)a
C(3)–H(3A)…O(5)b
C(3)–H(3B)…O(3)c
C(2)–H(2A)…O(4)d
0.990
0.990
0.990
0.990
2.568
2.394
2.456
2.501
3.555(8)
3.244(8)
3.340(8)
3.387(8)
174.914
143.542
148.483
148.775
O(3)–S(1)–O(4)
O(5)–S(1)–O(4)
O(5)–S(1)–O(3)
C(3)–O(4)–S(1)
C(3)–C(1)–C(1A)
96.9(2)
107.1(3)
107.2(2)
115.2(4)
112.4(4)
C(2)–O(3)–S(1)
O(4)–C(3)–C(1)
O(3)–C(2)–C(1)
C(2)–C(1)–C(1A)
N(1)–C(1)–C(1A)
114.5(4)
108.8(5)
108.4(5)
112.2(4)
105.7(6)
D and A are the hydrogen-bond donor and acceptor, respectively.
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