New spirans containing a 1,5-benzodithiepine system, derived from methylbenzenes. Conformational transmission

Article abstract of DOI:10.1021/ol990335p

A synthesis of three new spirans, derived from methylbenzenes, containing the 1,5-benzodithiepine system is reported. X-ray structure proved the identity of model monospiran 9. In the solid and liquid state, the conformation of the seven-membered ring is chair, and the five-membered ring has the envelope conformation. The effect of conformational transmission in spirans 9 and 10 was observed. The synthesis of trispirans from hexamethylbenzene using the proposed scheme is also possible.

Full text of DOI:10.1021/ol990335p

ORGANIC
LETTERS
2000
Vol. 2, No. 4
425-427
New Spirans Containing a
1,5-Benzodithiepine System, Derived
from Methylbenzenes. Conformational
Transmission
Joanna Baran´ska, Jacek Grochowski, Janusz Jamrozik,* and Paweł Serda
Department of Organic Chemistry, Jagiellonian UniVersity, 30-060 Krako´w, Poland,
and Regional Laboratory of Physicochemical Analysis and Structural Research,
Jagiellonian UniVersity, 30-060 Krako´w, Poland
jamrozik@chemia.uj.edu.pl
Received October 28, 1999
ABSTRACT
A synthesis of three new spirans, derived from methylbenzenes, containing the 1,5-benzodithiepine system is reported. X-ray structure proved
the identity of model monospiran 9. In the solid and liquid state, the conformation of the seven-membered ring is chair, and the five-membered
ring has the envelope conformation. The effect of conformational transmission in spirans 9 and 10 was observed. The synthesis of trispirans
from hexamethylbenzene using the proposed scheme is also possible.
The chemistry of spirans has been studied extensively from
many points of view.1,2 Much interest has been focused on
the bonding character of the central spiroatom. In the past
few years many aspects of spiran chemistry have been
developed such as conformational transmission,3 spirocon-
jugation,4 helical structure,5 and photochromism.6
A new group of spirans are the compounds containing the
1,5-benzodithiepine system.7
this compound gave ester 1, which was reduced with LiAlH4
to tetrol 2. Finally, treatment of tosylate 3 with the sodium
salt of 1,2-benzenedithiol in a sealed tube afforded dispiran
4 as a stable, high-melting compound. In the same way, from
prehnitene were obtained new compounds 5-8.
All the new compounds 1-8 were characterized by
elemental analyses and spectroscopic data. Unfortunately,
low solubility of spirans 4 and 8 caused such a weak intensity
of NMR spectra in low temperature that the respective spectra
could not be interpreted.8 In this situation, using the method
The reaction of durene with NBS yields 1,2,4,5-tetrakis-
(bromomethyl)benzene. In the reaction with ethyl malonate
10.1021/ol990335p CCC: $19.00 © 2000 American Chemical Society
Published on Web 01/26/2000

described above,9 we obtained new monospiran 9. This model
spiran 9 contained the seven-membered 1,5-dithiepine ring
identical with the rings in dispirans 4 and 8.
The environment of the spiroatom C11 deviates from
tetrahedral symmetry: the valency angle C9-C11-C10 is
112.09°, whereas the angle C12-C11-C13 is 103.58°. Their
The structure of 9 was determined from X-ray data.10
A
ν (cm-1) ) 3049, 2904 (CH2), 1442, 751; 1H NMR (CDCl3) δ ) 2.96
(broad s, 16H, CH2, CH2S), 7.03 (s, 2H, aromatic H), 7.16-7.26 (m, 4H,
aromatic H), 7.46-7.59 (m, 4H, aromatic H); 13C NMR (CDCl3) δ ) 43.6,
48.2, 52.0, 124.8, 126.4, 127.4, 133.1, 141.0; MS (EI) m/z (%) ) 490 (34)
M+, 349 (50), 207 (94), 193 (100), 178 (43). Anal. Calcd for C28H26S4
(490.82): C, 68.51; H, 5.35. Found: C, 68.28; H, 5.13. Dispiro[bis(2H-
benzo[f]-3,4-dihydro-1,5-dithiepine-3,2′,3,5′)cyclopentano[e′]indan] (8).
Dispirane 8 was obtained analogously from 7 in 16% yield, colorless crystals
(benzene), mp 206-207 °C: IR (KBr) ν (cm-1) ) 3044, 2901, 2835 (CH2),
1442, 1268, 760; 1H NMR (CDCl3) δ ) 2.97 (broad s, 16H, CH2, CH2S),
7.02 (s, 2H, aromatic H), 7.17-7.26 (m., 4H, aromatic H), 7.42-7.59 (m,
4H, aromatic H); 13C NMR (CDCl3) δ ) 43.2, 44.0, 45.1, 48.6, 123.3,
127.7, 132.1, 133.5, 137.7, 139.9; MS (EI) m/z (%) ) 490 (29) M+, 349
(45), 207 (81), 193 (100), 178 (24). Anal. Calcd for C28H26S4 (490.82): C,
68.51; H, 5.35. Found: C, 68.07; H, 5.25. Spiro(2H-benzo[f]-3,4-dihydro-
1,5-dithiepine-3,2′-indan) (9). Spirane 9 was prepared similarly by treating
the ditosylate of 2,2-bis(hydroxymethylo)indan9 with the sodium salt of
1,2-benzenedithiol: 23% yield; colorless crystals (benzene); mp 117-118
°C; IR (KBr) ν (cm-1) ) 2903, 2830 (CH2), 1440, 1270, 751; 1H NMR
(CDCl3) δ ) 2.94 (broad s, 8H, CH2, CH2S), 7.14-7.34 (m, 6H, aromatic
H), 7.57 (broad s, 2H, aromatic H); 13C NMR (CDCl3) δ ) 43.1, 43.7,
48.4, 125.0, 126.6, 127.6, 133.4, 134.2, 141.3; MS (EI) m/z (%) ) 284
(100) M+, 156 (36), 153 (48), 143 (93), 129 (89). Anal. Calcd for C17H16S2
(284.43): C, 71.79; H, 5.67. Found: C, 71.52; H, 5.76. New compounds
1-3 and 5-7 were obtained according to procedures described in ref 3.
Data for new compounds 1-3 and 5-7 follows. 2,2,6,6-Tetrakis-
(ethoxycarbonyl)cyclopentano[f]indan] (1): colorless crystals (ethanol);
yield 58%; mp 161-163 °C; IR (KBr) ν (cm-1) ) 2985, 2969, 2920 (CH2,
perspective view of the molecule 9 with the atom numbering
scheme is given in Figure 1. The compound 9 belongs to
Figure 1. Molecular structure of spiran 9.
asymmetric spirans. The spiroatom C11 joins two rings-
the seven-membered ring (S1, C8, C3, S2, C10, C11, C9)
containing two sulfur heteroatoms and the five-membered
ring (C11, C13, C14, C15, C12). Both rings are condensed
with aromatic moieties (C3, C4, C5, C6, C7, C8 and C14,
C15, C16, C17, C18, C19, respectively). To visualize the
complex geometry of the molecule, a continuous symmetry
measure11 (CSM) can be employed. The seven-membered
heteroring has the chair conformation with a total puckering
amplitude of 0.973(1) and corresponds very closely to an
H-form.12 The moiety composed of atoms numbered 1
through 13 (involving the 1,5-benzodithiepine fragment) has
a near-mirror symmetry with the mirror plane passing
through the spiroatom C11 and intersecting bonds C3-C8
and C5-C6. The continuous symmetry measure (CSM) has
a value of 0.0186. The second moiety, C11-C19, has also
a near-mirror plane symmetry with a CSM value of 0.0035.
The mirror plane passes through the spiroatom C11 and
intersects bonds C14-C15 and C17-C18. Both symmetry
planes are inclined at an angle of 87°. The five-membered
ring has an envelope conformation with the plane C12-
C11-C13 inclined at an angle of 27° with the planar
fragment C12-C19.
1
CH3), 1725 (CO), 1283, 1054, 907; H NMR (CDCl3) δ ) 1.25 (t, J ) 7
Hz, 12H, CH3), 3.51 (s, 8H, CH2), 4.17/4.21 (q, J ) 7 Hz, 8H, OCH2),
7.01 (s, 2H, aromatic H); 13C NMR (CDCl3) δ ) 14.0, 40.1, 60.8, 61.7,
120.0, 139.0, 171.7; MS (EI) m/z (%) ) 446 (24) M+, 297 (100). Anal.
Calcd for C24H30O8 (446.54): C, 64.55; H, 6.78. Found: C, 64.10; H, 6.82.
2,2,6,6-Tetrakis(hydroxymethyl)cyclopentano[f]indan] (2): colorless crys-
tals (ethanol); yield 51%; mp 274-275 °C; IR (KBr) ν (cm-1) ) 3314
1
(OH), 2937, 2832 (CH2), 1082, 1032; H NMR (DMSO-d6) δ ) 2.62 (s,
8H, CH2), 3.35 (s, 8H, OCH2), 4.60 (t, J ) 5.0 Hz, 4H, OH), 6.91 (s, 2H,
aromatic H); 13C NMR (DMSO-d6) δ ) 37.1, 50.0, 64.4, 121.0, 140.2; MS
(EI) m/z (%) ) 278 (16) M+, 193 (100). Anal. Calcd for C16H22O4
(278.38): C, 69.03; H, 7.98. Found: C, 69.10; H, 8.20. Tetratosylate of
2,2,6,6-tetrakis(hydroxymethyl)cyclopentano[f]indan] (3): colorless crys-
tals (acetone); yield 57%; mp 218-219 °C; IR (KBr) ν (cm-1) ) 2958,
2853 (CH2, CH3), 1358, 1178 (SO2), 1099; 1H NMR (CDCl3) δ ) 2.46 (s,
12H, CH3), 2.66 (s, 8H, CH2), 3.91 (s, 8H, OCH2), 6.76 (s, 2H, aromatic
H), 7.26-7.35 (m, 8H, aromatic H), 7.71-7.73 (m, 8H, aromatic H); 13C
NMR (CDCl3) δ ) 21.7, 37.7, 47.3, 71.1, 121.4, 127.9, 130.0, 132.4, 138.8,
145.2. Anal. Calcd for C44H46O12S4 (895.18): C, 59.03; H, 5.19. Found:
C, 58.72; H, 5.31. 2,2,5,5-Tetrakis(ethoxycarbonyl)cyclopentano[e]indan]
(5): colorless crystals (ethanol); yield 50%; mp 82-84 °C.; IR (KBr) ν
1
(cm-1) ) 2989, 2970, 2890 (CH2, CH3), 1739 (CO), 1258, 1065, 860; H
NMR (CDCl3) δ ) 1.25 (t, J ) 7 Hz, 12H, CH3), 3.50 (s, 4H, CH2), 3.55
(s, 4H, CH2), 4.18/4.22 (q, J ) 7 Hz, 8H, OCH2), 7.00 (s, 2H, aromatic
H); 13C NMR (CDCl3) δ ) 14.0, 38.9, 40.4, 60.5, 61.7, 122.8, 135.7, 138.9,
171.7; MS (EI) m/z (%) ) 446 (19) M+, 297 (100). Anal. Calcd for
C24H30O8 (446.54): C, 64.55; H, 6.78. Found: C, 64.49; H, 6.92. 2,2,5,5-
Tetrakis(hydroxymethyl)cyclopentano[e]indan] (6): colorless crystals
(methanol); yield 18%; mp 192-193 °C; IR (KBr) ν (cm-1) ) 3261 (OH),
2926, 2830 (CH2), 1090, 1023; 1H NMR (DMSO-d6) δ ) 2.60 (s, 4H,
CH2), 2.69 (s, 4H, CH2), 3.40 (s, 8H, OCH2), 4.59 (br. s, 4H, OH), 6.93 (s,
2H, aromatic H); 13C NMR (DMSO-d6) δ ) 35.9, 37.45, 49.8, 64.6, 122.3,
138.5, 140.1; MS (EI) m/z (%) ) 278 (9) M+, 193 (100). Anal. Calcd for
C16H22O4 (278.38): C, 69.03; H, 7.98. Found: C, 68.72; H, 8.14.
Tetratosylate of 2,2,5,5-tetrakis(hydroxymethyl)cyclopentano[e]indan]
(7): colorless crystals (acetone); yield 34%; mp 151-152 °C; IR (KBr) ν
(cm-1) ) 2960, 2848 (CH2, CH3), 1361, 1180 (SO2), 1100; 1H NMR
(CDCl3) δ ) 2.46 (s, 12H, CH3), 2.57 (s, 4H, CH2), 2.71 (s, 4H, CH2),
3.92 (s, 8H, OCH2), 6.85 (s, 2H, aromatic H), 7.30-7.36 (m, 8H, aromatic
H), 7.68-7.73 (m, 8H, aromatic H); 13C NMR (CDCl3) δ ) 21.7, 36.6,
38.1, 47.1, 71.2, 123.6, 127.9, 130.1, 132.3,136.2, 138.7, 145.2. Anal. Calcd
for C44H46O12S4 (895.18): C, 59.03; H, 5.19. Found: C, 58.65; H, 5.44.
(9) Smolin´ski, S.; Paluchowska, M. Monatsh. Chem. 1980, 111, 413-
421.
(1) Ginsburg, D. Top. Curr. Chem. 1987, 137, 1-17.
(2) Jamrozik, J.; Schab, S. Wiad. Chem. 1998, 52, 269-281.
(3) Jamrozik, J.; Schab, S. Monatsh. Chem. 1994, 125, 1145-1151.
(4) Maslak, P.; Chopra, A. J. Am. Chem. Soc. 1993, 115, 9331-9332.
(5) Grochowski, J.; Rutkowska, M.; Rys, B.; Serda, P.; Snatzke, G. Chem.
Ber. 1992, 125, 1837-1841.
(6) Favaro, G.; Masetti, F.; Mazzuchato, U.; Ottavi, G.; Allegrini, P.;
Malatesta, V. J. Chem. Soc., Faraday Trans. 1994, 90, 333-338.
(7) St-Jacques, M. Can. J. Chem. 1986, 64, 2142-2147.
(8) Experimental Details. Melting points (uncorrected): Boetius hot-
stage microscope. IR: Bruker IFS 48. 1H and 13C NMR: Bruker AMX
500 (500 MHz). Chemical shifts are referenced to interal SiMe4. MS:
Finnigan MAT 44S (EI, 70 eV). Dispiro[bis(2H-benzo[f]-3,4-dihydro-
1,5-dithiepine-3,2′,3,6′)cyclopentano[f ′]indan] (4). A mixture of 60 mL
of ethyl cellosolve, 0.20 g (8.8 mmol) of sodium, 0.64 g (4.4 mmol) of
1,2-benzenedithiol, and 2.00 g (2.2 mmol) of 3 in sealed tube was stirred
at 130 °C for 30 h. After evaporation of the solvent, the residue was
dissolved in benzene and sodium tosylate was filtered off. Product 4 was
purified chromatographically on Al2O3 using benzene as an eluent: colorless
crystals (chloroform-methanol); 132 mg (13%); mp 287-288 °C; IR (KBr)
(10) The structure was solved and refined using the SHELX-97 system
(Sheldrick, G. M. SHELX-97, a program for structure solution and
refinement. 1997, Goettingen University). Details of the crystal structure
investigation are available free of charge via the Internet at http://
pubs.acs.org.
426
Org. Lett., Vol. 2, No. 4, 2000

1
significant departure from the ideal value of 109.28° corre-
sponds to the classic rule of Thorpe-Ingold.13 Similar effects
were observed in crystal structures of asymmetrically strained
spirans containing nine-membered heterorings.14,15 The ge-
ometry of the molecule seems to result also from the stiffness
of the terminal aromatic substituents and repulsion of the
sulfur atoms.
In contrast to the H NMR spectrum (-90 °C) of the
model 9, the spectrum of 10 is more complicated and shows
the following signals: δ ) 2.62/2.75 (AB, J ) 14 Hz, 2H,
CH2S), 2.71/2.96 (AB, J ) 14 Hz, 2H, CH2S), 1.88/3.88
(AX, J ) 12 Hz, 2H, CH2C), 2.10/2.36 (AB, J ) 12 Hz,
2H, CH2C)swhen the 1,5-dithiepine ring adopts the chair
(C) conformationsand δ ) 2.52/3.80 (AX, J ) 14 Hz, 4H,
CH2S), 2.00/2.74 (AX, J ) 12 Hz, 4H, CH2C)sin the case
of the twist-boat (TB) conformation.
1
The H NMR spectra of 4, 8, and 9 recorded at room
temperature revealed broad singlets at δ ) 2.96, 2.97, and
2.94 for all methylene protons (CH2S, CH2), respectively.
This result is probably connected with rapid inversion of the
The interconversion barrier of C-TB conformations of the
1,5-dithiepine ring at the coalescence temperature of -15
°C, calculated16 for the AX signal at δ ) 2.52/3.80, is equal
to 12.8 kcal/mol.
1
1,5-dithiepine ring. It was supported by H NMR measure-
ments of the model spiran 9 at low temperatures (down to
-90 °C). Then the broad singlet at δ ) 2.94 which was
produced by methylene protons was split at low temperature
and three other signals appeared at δ ) 2.77/2.89 (AB, J )
14 Hz, CH2S) as well as singlets at δ ) 2.78 and 3.42 for
acyclic methylene protons. The shape of the 1H NMR
spectrum allowed the attribution of the chair conformation
also in solution for the 1,5-dithiepine ring.
It seems probable that the 1,5-dithiepine rings adopt a
similar conformation also in dispirans 4 and 8. In fact, these
compounds exhibit an identical configuration around the
spiroatoms as in the model monospiran 9 (1,5-benzodithie-
pine-spiroatom-five-membered ring). A change of config-
uration around the spiroatom in spiran 103 (1,5-benzodithie-
pine-spiroatom-seven-membered ring) affects the con-
formation of benzodithiepine.
In the present authors’ opinion the changes observed in
the shape of NMR spectra of spirans 9 and 10 are the result
of mutual interaction of both spiran components transmitted
by the spiroatom, the effect of which is analogous to the
well-known effect of the Barton conformational transmis-
sion.17
Structural consequences of the conformational transmission
will be the subject of future reports. It should also be possible
to develop a general route described above to obtain
trispirane from hexamethylbenzene18 and containing the 1,5-
benzodithiepine system.
OL990335P
(11) Zabrodsky, H.; Peleg, S.; Avnir, D. J. Am. Chem. Soc. 1993, 115,
8278-8289.
(12) Evans, G. G.; Boeyens, J. A. Acta Crystallogr. 1989, B45, 581-
590.
(13) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. J. Chem. Soc. 1915,
107, 1080-1106.
(14) Karle, I. L.; Grochowski, J. Acta Crystallogr. 1979, B35, 1293-
1295.
(15) Rys, B.; Szneler, E.; Grochowski, J.; Serda, P.; Duddeck, H. J. Mol.
Struct. 1992, 271, 301-309.
On the basis of 2D NMR spectra (TOCSY, NOESY),
spiran 10 at -90 °C was ascribed two dominant conforma-
tions of the heterocyclic ring: chair and twist-boat with a
population of 2:1.
(16) Sandstroem, J. Dynamic NMR Spectroscopy; Academic Press:
London, 1982.
(17) Barton, D. H. R.; Head, A. J.; May, P. J. J. Chem. Soc. 1957, 935-
944.
(18) Jamrozik, J.; Z˙ esłwski, W. Chem. Ber. 1994, 127, 2471-2474.
Org. Lett., Vol. 2, No. 4, 2000
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