Synthesis and stereochemistry of some new spiro and polyspiro-1,3-dithiane derivatives

Article abstract of DOI:10.1016/j.tet.2008.05.065

The synthesis of new spiro and trispiro compounds with 2,4,8,10-tetrathiaspiro[5.5]undecane and 7,11,18,21-tetrathia[5.2.2.5.2.2]heneicosane units is reported. The structural analysis was carried out by NMR investigations and the X-ray single crystal mole

Full text of DOI:10.1016/j.tet.2008.05.065

Tetrahedron 64 (2008) 7295–7300
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis and stereochemistry of some new spiro
and polyspiro-1,3-dithiane derivatives
a
b
a
a
a
ˆ
S¸erban Andrei Gaz , Eric Condamine , Niculina Bogdan , Anamaria Terec , Elena Bogdan ,
Yvan Ramondenc b, Ion Grosu a
,
*
a Organic Chemistry Department, CCOCCAN, ‘Babes-Bolyai’ University, 11 Arany Janos, RO-400028 Cluj Napoca, Romania
b Facult´e de Sciences, Universite´ de Rouen, IRCOF, UMR 6014, 76821, Mont Saint Aignan, Cedex, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 March 2008
Received in revised form 27 April 2008
Accepted 15 May 2008
Available online 20 May 2008
The synthesis of new spiro and trispiro compounds with 2,4,8,10-tetrathiaspiro[5.5]undecane and
7,11,18,21-tetrathia[5.2.2.5.2.2]heneicosane units is reported. The structural analysis was carried out by
NMR investigations and the X-ray single crystal molecular structure determined for one of the com-
pounds. The barriers for the flipping of the 1,3-dithiane units are determined by variable temperature
NMR experiments.
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
derivatives (tetrathiapentaerythritol) and the difficult access to the
starting tetramercapto derivative itself. Only the paper of Backerand
Six-membered ring spiranes and polyspiranes are intriguing
targets in organic chemistry. Their stereochemistry is correlated
with the helical chirality of the spiro[5.5]undecane skeleton.1–4 The
conformational analysis of six-membered ring spiranes was mainly
carried out using NMR methods and revealed flexible or ananco-
meric structures in correlation with the substitution of the spirane
skeleton.1–6 The majority of the investigations of six-membered
ring spiranes were focused on derivatives bearing 1,3-dioxane
rings. The advantage of the investigations on spiro-1,3-dioxanes
consisted of the fact that the stereochemistry of 1,3-dioxane system
itself is well known7–10 and spiro-1,3-dioxanes are appropriated for
NMR investigations.11
Evenhuis,15 published in 1937, deals with the synthesis of 3,9-
disubstituted-2,4,8,10-tetrathiaspiro[5.5]undecane derivatives by
the direct thioacetalyzation reaction. The parent 2,4,8,10-tetra-
thia[5.5]undecane 2 (Scheme 1) was obtained by the reaction of the
tetraacetylated derivative
1 with formaldehyde under acidic
conditions.16,17 Some spiro-1,3-dithianes (4), with chiral centers,
were obtained via the reaction of double lithiated derivative 3 with
various carbonyl compounds (substituted benzaldehydes, for-
mylcalixarenes, and formylbenzocrown ethers)16–18 as electrophiles
(Scheme 1).
AcS
AcS
SAc
SAc
The 1,3-dithiane derivatives are less studied12 than the corre-
sponding 1,3-dioxanes. Eliel13 and Pihlaja14 determined the A-
values for some alkyl, aryl, and polar substituents located at different
positions of the 1,3-dithiane ring. These investigations revealed for
alkyl and aryl groups similar A-values with those found in the
cyclohexane series, while for several polar groups located at position
2, the preference for the axial orientation was observed.
The literature data discuss few spiro-1,3-dithianes with 2,4,8,10-
tetrathia[5.5]undecane skeleton. Maybe the reduced number of
publications (compared to the very large number of papers
concerning similar spiranes with oxygen atoms) can be explained by
the difficulties encountered in the synthesis of these spiranes by the
condensation reaction of carbonyl compounds with tetramercapto
S
S
S
S
BuLi
CH2O
+
2
1
10
2
S
S
HO
S
9
S
OH
1
11
R-CHO
*
6
3
Li
*
Li
7
5
S
S
R
S
S
R
8
4
3
4
R=phenyl, calixarene-4'-yl, benzocrown-3'-yl
Scheme 1.
Compounds 4 exhibit complex stereochemistry due to the two
chiral centers (R or S configurations at the secondary alcohols) and
due to the chirality (M or P configuration) of the spirane skeleton.
These compounds exhibit three diastereoisomers (d1: RPR, SMS; d2:
RMR, SPS, and d3: SPR, RMS). They were used for the synthesis of
* Corresponding author. Tel.: þ40 264 593833; fax: þ40 264 590818.
E-mail address: igrosu@chem.ubbcluj.ro (I. Grosu).
0040-4020/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2008.05.065

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S¸.A. Gaz et al. / Tetrahedron 64 (2008) 7295–7300
7296
supramolecular structures with different guest molecules (e.g.,
60). The authors do not discuss the stereoisomerism of these de-
C
rivatives but the NMR spectra (e.g., in S.I. of Ref. 16) show that the
compounds were obtained and were investigated as mixtures of
diastereoisomers. The axial chirality of spiro-bis-dithiepins was
recently investigated.19 No X-ray molecular structure for usual
2,4,8,10-tetrathiaspiro[5.5]undecane compounds were reported
(except for 3,9-bis(dicyanomethylene)-2,4,8,10-tetrathiaspiro[5.5]-
undecane, a derivative, which exhibits sp2 carbon atoms in the 1,3-
dithiane spirane unit).20
We considered it of interest to find an appropriate procedure for
the direct synthesis of spiro compounds with 2,4,8,10-tetrathia-
spiro[5.5]undecane skeleton and to investigate the stereochemistry
and the properties of some 3,9-substituted derivatives of this
tetrathiaspirane.
2. Results and discussions
New 3,9-substituted-2,4,8,10-tetrathiaspiro[5.5]undecane de-
rivatives 6–9 and 7,11,18,21-tetrathiatrispiro[5.2.2.5.2.2]heneicosane
10 were obtained by the direct reaction of tetrathiapentaerythritol 5
with several carbonyl compounds (Scheme 2).
Figure 2. View of the lattice for 6 along the c crystallographic axis.
R1
R2
52-74%
CHCl3
R1
R2
S
9
S
S
R1
R2
HS
HS
SH
SH
11
7
1
5
C=O
+
3
S
(9: acetone)
The lattice exhibits a zigzag arrangement of the molecules
(Fig. 2). Each molecule exhibits four CH-p interactions. Two of them
5
r.t.
I2
R1= H ; R2 = meta-C6H4NO2
R1= H ; R2 = meta-C6H4OH
R1= H ; R2 = CH(CH3)2
R1= R2 = CH3
6
7
8
9
involve the axial proton of the methylene inside groups (positions 1
and 11) of the 1,3-dithiane units and the aromatic groups of two
neighboring molecules. The other two interactions are located on
the aromatic rings and involve the axial protons of the methylene
inside groups of the 1,3-dithiane units of the same neighboring
spirane molecules (the distance from the axial H atoms to the
centroid of the aromatic rings is d¼2.92 Å).
S
S
19
10
49%
Ph
20
8
HS
HS
SH
SH
12
6
O
Ph
Ph
+
CHCl3
S
S
r.t.
I2
5
10
2.2. Structural aspects in solution
Scheme 2.
A recently published procedure21 for the synthesis of the 1,3-
The stereochemistry of compounds 6–10 in solution was
deduced from NMR investigations. Despite the lower difference
between the energies of chair and TB (twist-boat) conformers
dithiane ring based on I2 catalysis was successfully adapted to the
synthesis of spiranes with 2,4,8,10-tetrathiaspiro[5.5]undecane
skeleton (yields 49–74%). The mechanism of this reaction is not yet
well known. All the other essays of usual thioacetalization22
reactions of the starting carbonyl compounds failed.
(
D
G0
¼2.9 kcal/mol)9 in 1,3-dithiane series than in the series
TB–chair
of other six-membered rings (e.g., cyclohexane,
D
G0
¼
TB–chair
4.9 kcal/mol; 1,3-dioxane,
D
G0
¼5.7 kcal/mol)9 the chair con-
TB–chair
formers are the main ones and in the further discussions only their
contributions to the stereochemistry of the compounds are con-
sidered. The characteristic stereoisomers for 6–10 are similar with
those found for the corresponding spiranes with 1,3-dioxane units.
Compound 6–8 exhibit anancomeric structures and the flipping
of the 1,3-dithiane rings is shifted toward the conformers in which
the larger substituents occupy the equatorial positions [R2¼meta-
C6H4NO2 (6); meta-C6H4OH (7); –CH(CH3)2 (8)]. Compounds 6–8
are chiral (due to the specific axial and helical chirality of spiro
compounds with six-membered rings) and they are obtained as
2.1. Structural aspects in solid state
The solid-state molecular structure for 6 was determined by
single crystal X-ray diffractometry. The ORTEP diagram (Fig. 1) re-
veals the chair conformation for the 1,3-dithiane units. The aro-
matic rings are equatorial and exhibit a rotameric behavior close to
that of the bisectional conformer. The angle between the aromatic
ring and the best plane of the 1,3-dithiane ring is 26ꢀ 280, while the
angle between the aromatic rings is 52ꢀ 420.
R2
3
R2
4
5
S
R1
S
R1
6 7
8
S
S
1
S
S
2
11
S
R2
R2
9
S
10
R1
R1
M
P
1,11 inside, 5,7 outside (positions)
Figure 1. ORTEP diagram for compound 6.
Scheme 3.

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S¸.A. Gaz et al. / Tetrahedron 64 (2008) 7295–7300
7297
S
9
S
S
3
S
1
5
11
7
H
O2N
NO2
(3,9)
Hax inside
Hax outside
(5,7)
(1,11)
Heq inside
(1,11)
Heq outside
(5,7)
5.00
4.50
4.00
3.50
3.00
ppm (t1)
Figure 3. 1H NMR spectrum (CDCl3, rt, fragment) of compound 6.
Figure 4. Variabletemperature1HNMRexperiments(CD2Cl2, fragments)forcompound9.
Table 1
NMR data (
d ppm) for compounds 6–8
The flexible behavior of the compound is proved by the NMR
spectra. At rt, the 1H NMR spectrum of 9 (Fig. 4) exhibits only two
Compound Solvent Temperature (K)
d
(ppm)
CH2 inside
Equatorial Axial Equatorial Axial
CH2 outside
singlets; a more deshielded one (
d
¼2.96 ppm) for the protons of the
heterocycles and another one (
d¼1.67 ppm) for the protons of the
methyl groups. The variable temperature NMR experiments (Fig. 4)
show the obtaining of the (de)coalescences of the signals at lower
temperatures (T¼255 K) and the spectrum run at 195 K reveals the
frozen structure.
6
7
8
9
9
10
10
CDCl3
CDCl3
CDCl3
CD2Cl2
CD2Cl2
CD2Cl2
CD2Cl2
295
295
295
308
195
295
190
4.12
4.17
3.83
2.91
2.93
2.57
2.72
2.66
2.52
3.15
3.34
2.83
2.68
3.67
3.84
2.59
2.54
2.24
3.11
2.78
The pattern of the NMR spectrum at 195 K for the protons of the
spirane unit is similar with the spectra of the anancomeric com-
pounds (Table 1, Figs. 3 and 4) while for the methyl groups at
positions 3 and 9 the spectrum shows two singlets corresponding
to the axial (dax¼1.69 ppm) and equatorial (deq¼1.48 ppm) orien-
tations, respectively. On the basis of these experiments and using
Eyring’s equations23 the barrier for the flipping of the 1,3-dithiane
rings in 9 was calculated (Table 2).
Compound 10 exhibits a semiflexible structure, the cyclohexane
rings (A and D, Scheme 5) situated at the extremities of the poly-
spirane unit are anancomeric and show the substituents at posi-
tions 3 and 15 in equatorial orientations, while the heterocyclic
middle part (rings B and C; Scheme 5) is flipping.
The trispirane is built up by merging three monospirane units
(AB, BC, and CD). Spirane 10 is a semiflexible polyspirane (trispir-
ane) with odd spirane units, which has similar groups at its ex-
tremities and exhibits six main conformers (3 diastereoisomers),
which represent separable enantiomers (E1: PPP$MMP$MPM;
E2: MMM$PPM$PMP; see Scheme 5 for E1). The flipping of the
1,3-dithiane units transforms one diastereoisomer into the other.
The transformation of a structure belonging to E1 into a structure
belonging to E2 or vice versa is possible only if some bonds are
broken and then they are rebuild in a new manner. The rt 1H NMR
spectrum of 10 (Fig. 5) exhibits for the protons of the heterocycles
two singlets (positions 8,19 in one side and 10,20 on the other side
are diastereotopic).
3.04
2.91
2.28
racemates (Scheme 3). The CH2 groups of the spirane units are
different in NMR. Positions 1 and 11 are oriented toward the other
1,3-dithiane ring and they are named methylene inside, while the
other two CH2 groups (positions 5 and 7) are oriented in opposite
direction and they are named methylene outside groups. On the
other hand, due to the anancomeric behavior of the compounds,
the NMR spectra exhibit different signals for the axial and equa-
torial protons of the spirane units. The equatorial protons of the
methylene inside groups are considerably more deshielded than
those of the methylene outside positions (Fig. 3, Table 1). The as-
signment of the signals was carried out on the basis of NOESY or/
and ROESY experiments.
1
The H NMR pattern for the spirane units exhibits two AB (AX)
systems (Fig. 3) with more deshielded equatorial protons for the
methylene inside groups (they are the closest to the sulfur atoms of
the neighboring heterocycle). The signals of the equatorial protons
exhibit a further splitting due to the long range coupling (4Jz2 Hz)
possible as result of the W (M) arrangement of the bonds Heq
–
C1(11)–C6–C5(7)–Heq
.
Compound 9 is flexible and both 1,3-dithiane rings are flipping.
The flipping of one of the heterocycles transforms one enantiomer
of the compound into the other (M$P; Scheme 4).
The variable temperature NMR experiments (Fig. 5) show at
lower temperatures the coalescence of the signals (T¼250 K) and at
190 K the spectrum corresponds to the frozen structure (Table 3).
The spectrum exhibits for the protons of the heterocycles pattern
similar to that recorded at rt for the anancomeric compounds 6–9.
Even if the four signals are well separated it is not possible to
assign them to one diastereoisomer or to a mixture of frozen dia-
stereoisomers. Despite this inconvenience, because the four groups
are well separated the barrier for the flipping of the middle part of
S
S
S
S
S
S
S
S
M
P
Scheme 4.

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7298
Table 2
Flipping barriers calculated from the coalescence temperatures and the chemical shifts of the signals for the protons 3(9)-CH3(ax), 3(9)-CH3(eq), 1(11)-Hax, 5(7)-Hax, 1(11)-Heq
,
and 5(7)-Heq measured in the low temperature 1H NMR spectra (CD2Cl2, 500 MHz) for compound 9
Compd
Temperature (K)
Dd (Hz)
D
G# (kcal/mol)
Mean D
G# value
(kcal/mol)
3(9)
1(11)
Heq, Hax
255
5(7)
3(9)
1(11)
5(7)
3(9)
1(11)
5(7)
CH3(ax), CH3(eq)
250
Hax, Heq
255
CH3(ax), CH3(eq)
108.5
Heq, Hax
538.2
Hax, Heq
434
CH3(ax), CH3(eq)
11.83
Heq, Hax
11.27
Hax, Heq
11.38
9
11.49ꢁ0.30
1
3
21
3. Conclusions
2
S
A
20
R
S
B
A
R
4
6
18
S
5
B
6
19
C
17
B
The efficient synthesis of some new spiro and trispiro-1,3-
dithianes is reported. The first single crystal X-ray molecular
structure for compounds with 2,4,8,10-tetrathiaspiro[5.5]undecane
shows the chair conformation for the 1,3-dithiane rings and the
zigzag disposition of the molecules in the lattice. The NMR studies
reveal flexible, semiflexible, and anancomeric structures in corre-
lation with the substituents located at the extremities of the
spirane skeleton. The barriers (
flipping of the heterocycles in the flexible and semiflexible com-
pounds were calculated by variable temperature NMR experiments.
S
16
S
S
9
7
S
C
8
9
S
12
11
13
D
12
10
D
R
II
I
15
R
14
6,9-anti-9,12-anti (MPM)
6,9-anti-9,12-syn (PMM)
C
C
D
G#¼10.95–11.83 kcal/mol) for the
S
B
A
R
S
A
R
6
6
B
S
B
C
9
S
C
9
S
S
S
4. Experimental part
12
S
D
12
D
II
R
III
R
4.1. General information
6,9-syn-9,12-anti (MMP)
6,9-syn-9,12-syn (PPP)
Routine 1H NMR (300 MHz) and 13C NMR (75 MHz) spectra,
COSY, HMQC, HMBC were recorded at rt in CDCl3 on a Bruker
300 MHz spectrometer, using the solvent line as reference. Variable
temperature NMR spectra and low temperature ROESY and NOESY
were recorded on Bruker Avance DMX 500 spectrometer in CD2Cl2.
Melting points were measured with a Kleinfeld melting point
apparatus and are uncorrected. Mass spectra were recorded on
ATI Unicam Automass, Micromass TofSpec E or a JEOL AX-500
spectrometer.
Scheme 5.
Thin layer chromatography (TLC) was conducted on silica gel 60
F254 TLC plates purchased from Merck. Preparative column (flash)
chromatography was performed using PharmPrep 60 CC (40–63
silica gel purchased from Merck.
mm)
TheexperimentalconditionsfortheX-raystructuredetermination
of compound 6 are as follows.25
The sample was studied on a Bruker AXS X8-APEX II with
graphite monochromatized Mo Ka radiation for 6. The structure
was solved with SIR-97,26 which reveals the non hydrogen atoms of
the molecule. After anisotropic refinement, many hydrogen atoms
may be found with a Fourier difference. The whole structure was
refined with SHELXL9727 by the full-matrix least-square tech-
niques. Atomic scattering factors from International Tables for
X-ray Crystallography (1992). ORTEP views were realized with
PLATON98. The structural data was deposited at the Cambridge
Crystallographic Data Center, deposition number is CCDC 678029
for 6.
Figure 5. Variable temperature 1H NMR experiments (CD2Cl2, fragments) for
compound 10.
the spirane could be estimated (Table 2). The measured barriers
for the flipping of the 1,3-dithiane rings in the spiranes are some-
what larger than the value measured for flipping 1,3-dithiane
Chemicals were purchased from Aldrich, Merck or Acros and
were used without further purification. Dimethylformamide was
freshly distilled from CaH2.
(D
G#¼10.3 kcal/mol).24
4.2. General procedure for the synthesis of 6–10
Table 3
Flipping barriers calculated from the coalescence temperatures and the chemical
shifts of the signals of the protons 8(10)-Hax, 19(20)-Hax, 8(10)-Heq, and 19(20)-Heq
measured in the low temperature 1H NMR spectra (CD2Cl2, 500 MHz) for compound
10
To a solution of aldehyde or ketone (1.2 mmol) and tetrathia-
pentaerythritol (100 mg, 0.5 mmol) in CHCl3 (in acetone for de-
rivative 9) iodine (0.25 mmol) was added and the resulting mixture
was stirred at rt. After completion of the reaction (TLC, hexane/
dichloromethane¼3:1) the mixture was quenched with aqueous
Na2S2O3. CHCl3 was then added and the organic layer was washed
twice with H2O, dried over Na2SO4, and filtered. Evaporation of the
solvent in vacuo gave the desired crude product. Further
Compd Temperature (K) Dd (Hz)
19(20) 8(10) 19(20) 8(10)
eq, Hax Hax, Heq Heq, Hax Hax, Heq Heq, Hax Hax, Heq
250 250 646.25 249.25 10.95 11.42
D
G# (kcal/mol)
19(20) 8(10)
Mean D
G#
value (kcal/mol)
H
10
11.18ꢁ0.33

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7299
purification was achieved by crystallization or separation by
column chromatography (petroleum ether/dichloromethane).
Tetrathiapentaerythritol (5) was obtained by a modificated pro-
cedure described by Yang28 for synthesis of SH groups. To a sus-
pension of LiAlH4 (100 mmol, 3.8 g) in 100 mL dry THF cooled with
(35). Anal. Calcd for C13H24S4 (308): C, 50.60; H, 7.84; S, 41.56.
Found: C, 50.71; H, 8.01; S, 41.28.
4.2.4. 3,3,9,9-Tetramethyl-2,4,8,10-tetrathiaspiro[5.5]undecane (9)
Yield: 69%; white crystals; mp¼191.4–191.7 ꢀC; crystallized
from acetone.
an ice bath,
a
solution of pentaerythrityl tetrathioacetate16
(9.185 mmol, 3.38 g) in 75 mL dry THF was added. The reaction
mixture was stirred under nitrogen atmosphere and the comple-
tion of the reaction was monitored by TLC. Water was carefully
added in order to neutralize the excess of LiAlH4, then the entire
mixture was quenched in concentrated HCl (12 M) and stirred until
a clear solution was obtained (pH¼1). The mixture was extracted
three times with dichloromethane (3ꢂ80 ml). The separated
organic phase was dried over Na2SO4 and the solvent was then
removed under reduced pressure. The crude product was crystal-
lized from ethanol to give white crystals (mp 72.1–72.5 ꢀC, yield:
1H NMR (300 MHz, CDCl3)
d
/ppm 1.68 (s, 12H, H-3, H-9), 2.97 (s,
8H, H-1, H-5, H-7, H-11). 13C NMR (75 MHz, CDCl3)
d
/ppm 25.6 (C-
6), 30.1 (CH3-3, CH3-9), 36.4 (CH2-5, CH2-7), 42.5 (CH2-1, CH2-11).
MS (EI, 70 eV) m/z (%) 280 [Mþ] (92), 237 (12.3), 206 (38), 191 (4),
173 (7), 141 (20), 132 (49), 117 (20), 99 (48), 85 (43), 74 (55), 59
(100), 45 (30), 41 (48). Anal. Calcd for C11H20S4 (280): C, 47.09; H,
7.19; S, 45.72. Found: C, 46.99; H, 7.02; S, 45.99.
4.2.5. 3,15-Diphenyl-7,11,18,21-tetrathiatrispiro-
[5.2.2.5.2.2]heneicosane (10)
1.49 g, 81%). 1H NMR (300 MHz, CDCl3)
d
/ppm 1.24 (t, J¼8.7 Hz, 4H),
Yield: 49%; white crystals; mp¼242.8–243.7 ꢀC; crystallized
from ethanol.
2.66 (d, J¼8.7 Hz, 8H); 13C NMR (75 MHz, CDCl3)
d/ppm 30.3
(C-quaternary), 38.7 (CH2).
1H NMR (500 MHz, CD2Cl2)
d/ppm 1.76–1.77 (m, 4H, Heq-2, Heq-
4, Heq-14, Heq-16), 1.82–1.86 (m, 4H, Hax-1, Hax-5, Hax-13, Hax-17),
1.95–2.01 (m, 4H, Hax-2, Hax-4, Hax-14, Hax-16), 2.46–2.51 (m, 4H,
4.2.1. 3,9-Bis(meta-nitrophenyl)-2,4,8,10-tetrathiaspiro-
[5.5]undecane (6)
Heq-1, Heq-5, Heq-13, Heq-17), 2.55–2.61 (m, 2H, H-3, H-15), 2.91 (s,
Yield: 52%; white crystals; mp¼225–226.5 ꢀC; purified by flash
chromatography (silica, CH2Cl2/petroleum ether¼1:1.25) Rf¼0.30.
4H, H-8, H-10), 3.05 (s, 4H, H-19, H-20), 7.19–7.22 (m, 2H, H-40, H-
400), 7.25–7.27 (m, 4H, H-20, H-200), 7.30–7.33 (m, 4H, H-30, H-300).
1H NMR (300 MHz, CDCl3)
d/ppm 2.72 (dd, J¼14.5, 2.1 Hz, 2H,
13C NMR (125 MHz, CD2Cl2)
d/ppm 26.2 (C-9), 30.4 (CH2-2, CH2-4,
H
eq-5, Heq-7), 2.92 (d, J¼14.5 Hz, 2H, Hax-1, Hax-11), 3.15 (d,
CH2-14, CH2-16), 35.0 (CH2-8, CH2-10, CH2-19, CH2-20), 38.2 (CH2-1,
CH2-5, CH2-13, CH2-17), 44.5 (CH2-3, CH2-15), 51.1 (C-6, C-12),
126.6, 127.4, 128.9 (CH-tertiary aromatic carbon atom), 147.3 (C-
quaternary aromatic carbon atom). MS (EI, 70 eV) m/z (%) 512 [Mþ]
(81), 393 (10), 353 (20), 322 (16), 289 (21), 189 (20), 157 (70), 129
(53), 117 (42), 104 (45), 91 (100). Anal. Calcd for C29H36S4 (512): C,
67.92; H, 7.08; S, 25.01. Found: C, 68.05; H, 7.22; S, 24.73.
J¼14.5 Hz, 2H, Hax-5, Hax-7), 4.12 (dd, J¼14.5, 2.1 Hz, 2H, 2Heq-1,
H
eq-11), 5.18 (s, 2H, H-3, H-9), 7.56 (t (overlapped dd), JzJ0¼8.1 Hz,
2H, H-50, H-500), 7.87–7.89 (m, 2H, H-60, H-600), 8.20 (ddd, 2H, J¼8.1,
2.1, 0.9 Hz, H-40, H-400), 8.41 (t (overlapped dd), JzJ0¼2.1 Hz, 2H, H-
20, H-200). 13C NMR (75 MHz, CD2Cl2)
d/ppm 22.7 (C-6), 36.9 (CH2-5,
CH2-7), 42.9 (CH2-1, CH2-11), 50.7 (CH-3, CH-9), 123.2, 123.7, 129.9,
134.1 (CH-tertiary aromatic carbon atoms), 140.0 (C-quaternary
aromatic carbon), 148.5 (C–NO2 quaternary aromatic carbon atom).
MS (CI) m/z (%) 467 [MþH]þ. Anal. Calcd for C19H18N2O4S4 (466): C,
48.91; H, 3.89; N, 6.00; S, 27.49. Found: C, 49.17; H, 3.77; N, 6.11; S,
27.31.
Acknowledgements
We acknowledge the financial support of this work by UEFISCSU
(projects Td 56/2007) and by CEEX-program (project 2Cex06-11-
30).
4.2.2. 3,9-Bis(meta-hydroxyphenyl)-2,4,8,10-tetrathiaspiro-
[5.5]undecane (7)
Yield: 74%; pale yellow crystals; mp¼234.5–235.3 ꢀC; crystal-
References and notes
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1H NMR (300 MHz, CD3COCD3)
d/ppm 2.66 (dd, J¼14.4, 2.1 Hz,
´
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(m, 4H, H-20, H-200, H-40, H-400), 7.18 (t (overlapped dd), JzJ0¼8.1 Hz,
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d/ppm
22.1 (C-6), 36.2 (CH2-5, CH2-7), 42.7 (CH2-1, CH2-11), 51.3 (CH-3,
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d
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ˆ
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