1,2-Dibromo-5-(4-tolylsulfonyl)-2,2a,4a,5,7a,7b-hexahydro-1H-7-oxa-5-azacyclobuta[e]inden-6-one
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807017011/av3083sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807017011/av30836bsup2.hkl |
CCDC reference: 647580
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.008 Å
- R factor = 0.099
- wR factor = 0.144
- Data-to-parameter ratio = 24.4
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ? PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 8 PLAT431_ALERT_2_C Short Inter HL..A Contact Br2 .. Br2 .. 3.56 Ang.
Alert level G PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
For related literature, see: Vasilyev et al. (2001); Balci (1981); Boshe & Huisgen (1965); Gözel et al. (1991); Huisgen & Gasteiger (1972); Kara et al. (1994); Kara & Balci (2003); Kelebekli et al. (2005); Kelebekli et al. (2006); Lysek & Vogel (2006); Paul et al. (2002); Reppe et al. (1948); Seçen et al. (1990); Şahin et al. (2006); Trost et al. (1992); Trost & Van Vranken (1993).
For preparation of 6a and 6 b, to a stirred solution of diol (5a) and (5 b) (0.525 g, 2.05 mmol) in anhydrous THF (20 ml) under N2 at room temperature p-toluensulfonyl isocyanate (0.8 g, 4.1 mmol= 0.62 ml) was added via syringe. The reaction was stirred at room temperature for 5 h and then the reaction temperature was increased to 335 K in 30 min. To another flask containing tris(dibenzylideneacetone)dipalladium chloroform complex (0.112 g, 108 µmol) in anhydrous THF (10 ml) under N2 at room temperature triisopropylphosphite (0.40 g, 1.94 mmol) was added dropwise and stirred at room temperature for 30 min until a clear yellow color was obtained. The prepared catalyst mixture was added to the main reaction mixture and stirred at 335 K for 12 h. After removal of the solvent under reduced pressure (325 K, 20 m mH g), the residue was purified on a silica gel (60 g) by elution with 20% ethyl acetate / hexane to afford 6 b (70 mg, 7.2%). White crystals, mp 469–470 K (from hexane/ethyl acetate). νmax (KBr); 3080, 3055, 3004, 2953, 1778, 1600, 1497, 1421, 1370, 1319, 1268, 1217, 1165, 1140, 1089, 1038 cm-1; 1H-NMR (200 MHz CDCl3 p.p.m.) 7.94 (br d, A part of AA' BB' system, J= 8.3 Hz, 2H, aromatic), 7.34 (br d, B part of AA'BB' system, J= 8.3 Hz, 2H, aromatic), 6.11 (br s, 2H, –CH=CH), 4.93 (d, J= 7.3 Hz,1H, —CH—O), 4.80 (dd, J= 7.2, 2.0 Hz,1H, —CH—N), 4.37 and 4.33 (td, J= 6.5, 1.2 Hz, 2H —CH—Br), 3.62 (td, J=10.1, 2.1 Hz, 1H, —CH), 3.17 (dd, J= 6.9, 1.4 Hz, 1H, —CH), 2.47 (s, 3H, arom-CH3); 13 C-NMR (50 MHz CDCl3 p.p.m.) δ 151.9 (C═O), 147.4 and 137.3 (ipso C's), 131.7, 130.6,130.4 and 125.0 (HC═CH and aromatic), 71.7 (C—O), 54.4 and 53.6 (—CH—Br), 45.1 and 43.7 (CH), 41.3 (—C—N), 23.7 (arom-CH3).
The H atoms were placed in geometrically idealized positions (C—H=0.93–0.98 Å) and treated as riding, with Uiso(H)=1.2Ueq(C) or 1.5Ueq(methyl C).
Recently, we successfully used cyclooctatetraene as starting material for synthesis of various stereospecific cyclitol isomers and their aminocyclitol derivatives (Kara et al., 1994; Kelebekli et al., 2005, 2006). In addition, some aminocyclitols have shown interesting inhibitor activities towards glycosidases (Paul et al., 2002; Lysek & Vogel 2006). It is known that both cis- and trans-7,8-dichloro-cycloocta-1,3,5-triene are obtained by chlorination of cyclooctatetraene 1 (Reppe et al., 1948; Gözel et al., 1991;Şahin et al., 2006) (Scheme). For synthesis of the aminoconduritol derivative, we performed bromination of cyclooctatetraene 1 in ice bath (Boshe & Huisgen, 1965; Huisgen & Gasteiger, 1972). The bromination product 2 was heated in CCl4 at 323 K to form 3. The photooxygenation of 3 and its reduction of O—O bond with thiourea resulted in formation of 5 (Balci, 1981; Seçen et al., 1990; Kara & Balci, 2003; Kelebekli et al., 2005, 2006). Pd(0)-catalyzed reactions provide the selective entry to amino alcohols with various regio- and stereoselectivity. Recently, vinyl oxazolidone-2-one has been synthesized by stereoselective Pd(0)-catalyzed reaction with cis-2-alkene-1,4-diol in a single step (Trost et al., 1992; Trost & Van Vranken, 1993). Using this method, oxazolidinone 6 b was synthesized from 5 b. The exact configuration of compound 6 b was determined by 1H and 13C– NMR spectra and an X-ray diffraction analysis. The resolved structure provides information on the stereochemical course of the cis-brom atoms, namely, both bromine atoms are cis to each other. It is known that bromination is a stereoscpecific anti-addition. In the light of all this findings, one can conclude that formation of cis-bromide occurrs during bromination of cyclooctatetraene 1 as a minor product along with major trans adduct. In order to confirm this unexpected result again, the bromination of cyclooctatetraene 1 was repeated, and consecutive yield of cis-bromide was 5–10%.
The molecular structure of 6 b is shown in Fig. 1, and the bond lengths and angles are listed in Table 1. As reported earlier, after the bromination of cyclooctatetraene 1, cis-bromide product was observed (Boshe & Huisgen, 1965; Huisgen & Gasteiger, 1972), but this type of adducts was not investigated in detail.
Compound 6 b contains a central cyclohexene ring with a cyclobutane and oxazolidinone moieties fused to it. The Br atoms have cis stereochemistry, in which Br1—C15 [1.926 (5)] and Br2—C16 [(1.933 (3)]Å bond lengths are comparable with the Br—C (1.94 (1), 1.93 (1) Å) bond lengths in the dibromotetraacetate compound (Kara et al., 1994), but there the Br atoms have trans
configuration. Because of cis configuration of the Br atoms in compound 5 b, oxazolidinone moiety leads to formation of the only product 6 b. All the substituents, including the oxazolidinone moiety and the bromine atoms are on the same side of the bicycle (syn conformation). In addition to this, the cyclobutane and the oxazolidinone rings have trans stereochemistry. The cyclobutane moiety is appreciably folded with C—C distances in the range 1.542 (7)–1.551 (7) Å. Due to the strong electronegativity of the Cl atoms, this range is larger [1.534 (3)–1.567 (3) Å] in the (1SR,2SR,3SR,4RS,5RS,6RS,7SR,8RS)-7,8-Dichlorobicyclo[4.2.0] octa-2,3,4,5-tetrayl tetraacetate structure Şahin et al., 2006). Finally the cyclohexene ring adopts a half-chair conformation with puckering parameters QT=0.283 (5) Å, θ =52.0 (2)and φ=84.3 (4) °. Electron localization was also found at the C13—C14 bond with a length of 1.310 (7)Å which is appreciably shorter for cyclohexene C=C bond. Tosyl O1 atom does not depart from the phenyl ring plane. The O1—S1—C5 and O2—S1—C5 bond angles, as well as the O—S bond lengths are essentially equal as expected (Kelebekli et al., 2006).
The closest Br···C intermolecular distance is 3.428 (6)Å with no hydrogen atom directed even approximately along this line, so the Br atoms do not participate in hydrogen bonds. In the crystal structure Br2 atoms are facing one another along the c axis and the Br2···Br2 interatomic distance is 3.556Å within the van der Waals distance of 3.70 Å. C15—Br1···Pi(phenyl) noncovalent interactions contribute to the stability of the overall structure. The C-donor bond vectors are directed more closely towards the mid-point of an individual aromatic bond (Br1···C6=3.428, Br1···C7=3.458 Å) rather then the ring centroid (X) with Br1···X=3.440 (4)Å and C—Br···X=144.16 (16)°. Most important, the bromine does not coordinate to the benzene ring symmetrically in striking contrast to the coaxial (delocalized) model reported by Hassel & Stromme (1959). Instead, the bromine is positioned over the rim (not over the center) of the phenyl ring which corresponds to one of the highest electron density positions. Such experimental location of bromine is in good agreement with the data on noncovalent binding of halogens to aromatic donors (Vasilyev et al., 2001).
In the crystal structure the adjacent phenyl moieties are stacked opposed to each other. The distance between ring centroids is 3.893 (5)Å and the corresponding slip angle is 7.4°. The crystal structure is also stabilized by two weak intermolecular hydrogen bonds (Fig. 3).
For related literature, see: Vasilyev et al. (2001); Balci (1981); Boshe & Huisgen (1965); Gözel et al. (1991); Huisgen & Gasteiger (1972); Kara et al. (1994); Kara & Balci (2003); Kelebekli et al. (2005); Kelebekli et al. (2006); Lysek & Vogel (2006); Paul et al. (2002); Reppe et al. (1948); Seçen et al. (1990); Şahin et al. (2006); Trost et al. (1992); Trost & Van Vranken (1993).
Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
C16H15Br2NO4S | F(000) = 944 |
Mr = 477.17 | Dx = 1.821 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 6799 reflections |
a = 10.8513 (4) Å | θ = 3.0–30.5° |
b = 6.0019 (3) Å | µ = 4.80 mm−1 |
c = 26.7246 (7) Å | T = 293 K |
β = 90.232 (2)° | Block, brown |
V = 1740.52 (12) Å3 | 0.32 × 0.21 × 0.20 mm |
Z = 4 |
Rigaku R-AXIS RAPID S diffractometer | 4398 reflections with I > 2σ(I) |
oscillation scans | Rint = 0.097 |
Absorption correction: multi-scan (Blessing, 1995) | θmax = 30.6°, θmin = 3.0° |
Tmin = 0.310, Tmax = 0.383 | h = −15→15 |
44718 measured reflections | k = −8→7 |
5328 independent reflections | l = −38→38 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.099 | w = 1/[σ2(Fo2) + 4.0303P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.144 | (Δ/σ)max < 0.001 |
S = 1.39 | Δρmax = 0.62 e Å−3 |
5328 reflections | Δρmin = −0.49 e Å−3 |
218 parameters |
C16H15Br2NO4S | V = 1740.52 (12) Å3 |
Mr = 477.17 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.8513 (4) Å | µ = 4.80 mm−1 |
b = 6.0019 (3) Å | T = 293 K |
c = 26.7246 (7) Å | 0.32 × 0.21 × 0.20 mm |
β = 90.232 (2)° |
Rigaku R-AXIS RAPID S diffractometer | 5328 independent reflections |
Absorption correction: multi-scan (Blessing, 1995) | 4398 reflections with I > 2σ(I) |
Tmin = 0.310, Tmax = 0.383 | Rint = 0.097 |
44718 measured reflections |
R[F2 > 2σ(F2)] = 0.099 | 0 restraints |
wR(F2) = 0.144 | H-atom parameters constrained |
S = 1.39 | Δρmax = 0.62 e Å−3 |
5328 reflections | Δρmin = −0.49 e Å−3 |
218 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.82396 (6) | −0.33398 (11) | 0.35382 (2) | 0.05280 (18) | |
Br2 | 0.97931 (7) | 0.00899 (15) | 0.43399 (2) | 0.0734 (3) | |
N1 | 1.0135 (4) | 0.2449 (8) | 0.18456 (15) | 0.0398 (10) | |
S1 | 1.08884 (13) | 0.2442 (3) | 0.13037 (5) | 0.0441 (3) | |
O1 | 1.1277 (4) | 0.4663 (8) | 0.11961 (15) | 0.0614 (12) | |
O2 | 1.1774 (4) | 0.0710 (8) | 0.13677 (14) | 0.0600 (12) | |
O3 | 0.9097 (4) | 0.5830 (7) | 0.18095 (15) | 0.0578 (11) | |
O4 | 0.8846 (3) | 0.3462 (6) | 0.24463 (12) | 0.0435 (9) | |
C1 | 0.6963 (6) | −0.0249 (14) | −0.0174 (2) | 0.078 (2) | |
H1A | 0.618 | 0.0001 | −0.0018 | 0.117* | |
H1B | 0.7041 | −0.1796 | −0.0259 | 0.117* | |
H1C | 0.7018 | 0.0637 | −0.0472 | 0.117* | |
C2 | 0.7985 (5) | 0.0399 (11) | 0.0183 (2) | 0.0515 (15) | |
C3 | 0.8497 (6) | 0.2495 (12) | 0.0169 (2) | 0.0564 (16) | |
H3 | 0.8235 | 0.3501 | −0.0074 | 0.068* | |
C4 | 0.9395 (5) | 0.3134 (10) | 0.0509 (2) | 0.0497 (14) | |
H4 | 0.9733 | 0.4557 | 0.0496 | 0.06* | |
C5 | 0.9780 (5) | 0.1634 (9) | 0.08647 (17) | 0.0392 (11) | |
C6 | 0.9301 (6) | −0.0502 (10) | 0.0878 (2) | 0.0506 (14) | |
H6 | 0.9588 | −0.1528 | 0.1112 | 0.061* | |
C7 | 0.8398 (6) | −0.1090 (10) | 0.0542 (2) | 0.0528 (15) | |
H7 | 0.8058 | −0.251 | 0.0556 | 0.063* | |
C8 | 0.9333 (5) | 0.4099 (9) | 0.20073 (19) | 0.0418 (12) | |
C9 | 1.0333 (4) | 0.0759 (9) | 0.22463 (17) | 0.0352 (10) | |
H9 | 1.0355 | −0.0748 | 0.2106 | 0.042* | |
C10 | 0.9155 (4) | 0.1127 (8) | 0.25475 (17) | 0.0347 (11) | |
H10 | 0.8498 | 0.0154 | 0.2421 | 0.042* | |
C11 | 0.9284 (5) | 0.0853 (9) | 0.31047 (17) | 0.0364 (11) | |
H11 | 0.8567 | 0.1481 | 0.3277 | 0.044* | |
C12 | 1.0497 (5) | 0.1659 (10) | 0.33545 (18) | 0.0431 (12) | |
H12 | 1.0403 | 0.3043 | 0.3545 | 0.052* | |
C13 | 1.1566 (5) | 0.1682 (10) | 0.3009 (2) | 0.0484 (14) | |
H13 | 1.2336 | 0.2019 | 0.3143 | 0.058* | |
C14 | 1.1500 (5) | 0.1263 (9) | 0.2528 (2) | 0.0426 (13) | |
H14 | 1.2232 | 0.1278 | 0.2348 | 0.051* | |
C15 | 0.9573 (5) | −0.1502 (9) | 0.33031 (18) | 0.0406 (12) | |
H15 | 1.004 | −0.2323 | 0.305 | 0.049* | |
C16 | 1.0479 (5) | −0.0463 (10) | 0.36853 (18) | 0.0460 (13) | |
H16 | 1.1276 | −0.1229 | 0.3698 | 0.055* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0580 (4) | 0.0512 (3) | 0.0492 (3) | −0.0040 (3) | 0.0102 (2) | 0.0088 (3) |
Br2 | 0.0826 (5) | 0.1077 (6) | 0.0299 (3) | −0.0011 (4) | −0.0012 (3) | −0.0001 (3) |
N1 | 0.046 (2) | 0.042 (2) | 0.031 (2) | 0.002 (2) | 0.0003 (17) | 0.0067 (18) |
S1 | 0.0397 (7) | 0.0582 (9) | 0.0345 (6) | −0.0040 (7) | 0.0007 (5) | 0.0086 (6) |
O1 | 0.059 (3) | 0.071 (3) | 0.054 (2) | −0.029 (2) | −0.0044 (19) | 0.014 (2) |
O2 | 0.050 (2) | 0.087 (3) | 0.043 (2) | 0.017 (2) | 0.0068 (17) | 0.009 (2) |
O3 | 0.076 (3) | 0.043 (2) | 0.054 (2) | 0.008 (2) | 0.000 (2) | 0.0120 (19) |
O4 | 0.051 (2) | 0.045 (2) | 0.0344 (18) | 0.0132 (18) | 0.0006 (15) | 0.0063 (16) |
C1 | 0.065 (5) | 0.111 (7) | 0.056 (4) | −0.006 (4) | −0.011 (3) | −0.018 (4) |
C2 | 0.047 (3) | 0.065 (4) | 0.042 (3) | 0.004 (3) | 0.003 (2) | −0.010 (3) |
C3 | 0.061 (4) | 0.072 (4) | 0.036 (3) | 0.003 (3) | −0.006 (3) | 0.017 (3) |
C4 | 0.056 (4) | 0.051 (4) | 0.042 (3) | −0.005 (3) | −0.002 (2) | 0.013 (3) |
C5 | 0.041 (3) | 0.047 (3) | 0.030 (2) | 0.000 (2) | 0.0018 (19) | 0.004 (2) |
C6 | 0.063 (4) | 0.043 (3) | 0.046 (3) | 0.004 (3) | 0.002 (3) | 0.006 (3) |
C7 | 0.060 (4) | 0.039 (3) | 0.059 (4) | −0.006 (3) | 0.001 (3) | −0.011 (3) |
C8 | 0.049 (3) | 0.040 (3) | 0.037 (3) | 0.002 (2) | −0.007 (2) | 0.004 (2) |
C9 | 0.041 (3) | 0.034 (3) | 0.031 (2) | 0.000 (2) | −0.0027 (19) | 0.0070 (19) |
C10 | 0.036 (3) | 0.038 (3) | 0.031 (2) | 0.002 (2) | −0.0020 (19) | 0.003 (2) |
C11 | 0.039 (3) | 0.042 (3) | 0.028 (2) | 0.007 (2) | −0.0011 (19) | 0.004 (2) |
C12 | 0.052 (3) | 0.044 (3) | 0.033 (2) | −0.001 (3) | −0.011 (2) | 0.000 (2) |
C13 | 0.041 (3) | 0.057 (4) | 0.047 (3) | −0.013 (3) | −0.013 (2) | 0.011 (3) |
C14 | 0.032 (3) | 0.052 (4) | 0.044 (3) | −0.004 (2) | −0.003 (2) | 0.011 (2) |
C15 | 0.045 (3) | 0.044 (3) | 0.033 (2) | 0.006 (2) | 0.006 (2) | 0.006 (2) |
C16 | 0.044 (3) | 0.063 (4) | 0.031 (2) | 0.012 (3) | −0.001 (2) | 0.010 (2) |
Br1—C15 | 1.926 (5) | C6—H6 | 0.93 |
Br2—C16 | 1.933 (5) | C14—C13 | 1.310 (7) |
S1—O2 | 1.425 (4) | C14—H14 | 0.93 |
S1—O1 | 1.428 (4) | C10—C11 | 1.504 (6) |
S1—N1 | 1.666 (4) | C10—H10 | 0.98 |
S1—C5 | 1.746 (5) | C4—C3 | 1.383 (8) |
O4—C8 | 1.344 (6) | C4—H4 | 0.93 |
O4—C10 | 1.466 (6) | C11—C15 | 1.542 (7) |
O3—C8 | 1.193 (6) | C11—H11 | 0.98 |
N1—C8 | 1.388 (7) | C13—H13 | 0.93 |
N1—C9 | 1.490 (6) | C2—C3 | 1.376 (9) |
C5—C4 | 1.373 (7) | C2—C7 | 1.384 (8) |
C5—C6 | 1.384 (8) | C2—C1 | 1.511 (8) |
C9—C14 | 1.501 (7) | C7—H7 | 0.93 |
C9—C10 | 1.530 (7) | C15—C16 | 1.546 (7) |
C9—H9 | 0.98 | C15—H15 | 0.98 |
C12—C13 | 1.486 (8) | C3—H3 | 0.93 |
C12—C16 | 1.550 (7) | C16—H16 | 0.98 |
C12—C11 | 1.551 (7) | C1—H1A | 0.96 |
C12—H12 | 0.98 | C1—H1B | 0.96 |
C6—C7 | 1.372 (8) | C1—H1C | 0.96 |
O2—S1—O1 | 120.4 (3) | C10—C11—C15 | 117.3 (4) |
O2—S1—N1 | 103.3 (2) | C10—C11—C12 | 117.9 (4) |
O1—S1—N1 | 108.6 (3) | C15—C11—C12 | 88.1 (4) |
O2—S1—C5 | 109.9 (3) | C10—C11—H11 | 110.6 |
O1—S1—C5 | 109.1 (3) | C15—C11—H11 | 110.6 |
N1—S1—C5 | 104.2 (2) | C12—C11—H11 | 110.6 |
C8—O4—C10 | 110.0 (4) | O3—C8—O4 | 123.3 (5) |
C8—N1—C9 | 110.5 (4) | O3—C8—N1 | 128.1 (5) |
C8—N1—S1 | 125.6 (4) | O4—C8—N1 | 108.5 (4) |
C9—N1—S1 | 123.6 (3) | C14—C13—C12 | 124.7 (5) |
C4—C5—C6 | 120.8 (5) | C14—C13—H13 | 117.7 |
C4—C5—S1 | 119.4 (4) | C12—C13—H13 | 117.7 |
C6—C5—S1 | 119.8 (4) | C3—C2—C7 | 118.6 (5) |
N1—C9—C14 | 110.0 (4) | C3—C2—C1 | 120.9 (6) |
N1—C9—C10 | 99.3 (4) | C7—C2—C1 | 120.4 (6) |
C14—C9—C10 | 114.3 (4) | C6—C7—C2 | 121.1 (6) |
N1—C9—H9 | 110.9 | C6—C7—H7 | 119.5 |
C14—C9—H9 | 110.9 | C2—C7—H7 | 119.5 |
C10—C9—H9 | 110.9 | C11—C15—C16 | 89.2 (4) |
C13—C12—C16 | 112.0 (5) | C11—C15—Br1 | 119.0 (4) |
C13—C12—C11 | 113.5 (4) | C16—C15—Br1 | 119.5 (3) |
C16—C12—C11 | 88.7 (4) | C11—C15—H15 | 109.2 |
C13—C12—H12 | 113.5 | C16—C15—H15 | 109.2 |
C16—C12—H12 | 113.5 | Br1—C15—H15 | 109.2 |
C11—C12—H12 | 113.5 | C2—C3—C4 | 121.3 (6) |
C7—C6—C5 | 119.2 (5) | C2—C3—H3 | 119.4 |
C7—C6—H6 | 120.4 | C4—C3—H3 | 119.4 |
C5—C6—H6 | 120.4 | C15—C16—C12 | 87.9 (4) |
C13—C14—C9 | 124.9 (5) | C15—C16—Br2 | 114.9 (4) |
C13—C14—H14 | 117.5 | C12—C16—Br2 | 112.4 (4) |
C9—C14—H14 | 117.5 | C15—C16—H16 | 113.1 |
O4—C10—C11 | 107.9 (4) | C12—C16—H16 | 113.1 |
O4—C10—C9 | 103.4 (4) | Br2—C16—H16 | 113.1 |
C11—C10—C9 | 115.5 (4) | C2—C1—H1A | 109.5 |
O4—C10—H10 | 109.9 | C2—C1—H1B | 109.5 |
C11—C10—H10 | 109.9 | H1A—C1—H1B | 109.5 |
C9—C10—H10 | 109.9 | C2—C1—H1C | 109.5 |
C5—C4—C3 | 119.0 (6) | H1A—C1—H1C | 109.5 |
C5—C4—H4 | 120.5 | H1B—C1—H1C | 109.5 |
C3—C4—H4 | 120.5 | ||
O2—S1—N1—C8 | 167.3 (4) | C13—C12—C11—C10 | −25.2 (7) |
O1—S1—N1—C8 | 38.4 (5) | C16—C12—C11—C10 | −138.7 (5) |
C5—S1—N1—C8 | −77.8 (5) | C13—C12—C11—C15 | 94.9 (5) |
O2—S1—N1—C9 | −6.5 (5) | C16—C12—C11—C15 | −18.6 (4) |
O1—S1—N1—C9 | −135.4 (4) | C10—O4—C8—O3 | 170.7 (5) |
C5—S1—N1—C9 | 108.4 (4) | C10—O4—C8—N1 | −10.2 (6) |
O2—S1—C5—C4 | −136.8 (4) | C9—N1—C8—O3 | 169.7 (5) |
O1—S1—C5—C4 | −2.8 (5) | S1—N1—C8—O3 | −4.8 (9) |
N1—S1—C5—C4 | 113.1 (5) | C9—N1—C8—O4 | −9.3 (6) |
O2—S1—C5—C6 | 43.1 (5) | S1—N1—C8—O4 | 176.2 (4) |
O1—S1—C5—C6 | 177.1 (4) | C9—C14—C13—C12 | 1.9 (10) |
N1—S1—C5—C6 | −67.0 (5) | C16—C12—C13—C14 | 104.2 (6) |
C8—N1—C9—C14 | −97.1 (5) | C11—C12—C13—C14 | 5.7 (8) |
S1—N1—C9—C14 | 77.5 (5) | C5—C6—C7—C2 | 1.8 (9) |
C8—N1—C9—C10 | 23.2 (5) | C3—C2—C7—C6 | −0.1 (9) |
S1—N1—C9—C10 | −162.2 (4) | C1—C2—C7—C6 | −178.1 (6) |
C4—C5—C6—C7 | −2.4 (8) | C10—C11—C15—C16 | 139.2 (4) |
S1—C5—C6—C7 | 177.7 (4) | C12—C11—C15—C16 | 18.6 (4) |
N1—C9—C14—C13 | 120.0 (6) | C10—C11—C15—Br1 | −97.1 (5) |
C10—C9—C14—C13 | 9.3 (8) | C12—C11—C15—Br1 | 142.3 (4) |
C8—O4—C10—C11 | 147.6 (4) | C7—C2—C3—C4 | −0.9 (9) |
C8—O4—C10—C9 | 24.7 (5) | C1—C2—C3—C4 | 177.1 (6) |
N1—C9—C10—O4 | −27.3 (4) | C5—C4—C3—C2 | 0.3 (9) |
C14—C9—C10—O4 | 89.8 (5) | C11—C15—C16—C12 | −18.6 (4) |
N1—C9—C10—C11 | −144.9 (4) | Br1—C15—C16—C12 | −141.9 (4) |
C14—C9—C10—C11 | −27.9 (6) | C11—C15—C16—Br2 | 95.2 (4) |
C6—C5—C4—C3 | 1.4 (9) | Br1—C15—C16—Br2 | −28.2 (6) |
S1—C5—C4—C3 | −178.7 (4) | C13—C12—C16—C15 | −96.3 (5) |
O4—C10—C11—C15 | 178.3 (4) | C11—C12—C16—C15 | 18.5 (4) |
C9—C10—C11—C15 | −66.6 (6) | C13—C12—C16—Br2 | 147.5 (4) |
O4—C10—C11—C12 | −78.4 (5) | C11—C12—C16—Br2 | −97.6 (4) |
C9—C10—C11—C12 | 36.7 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···O3i | 0.93 | 2.51 | 3.331 (7) | 148 |
C9—H9···O3i | 0.98 | 2.59 | 3.450 (7) | 147 |
Symmetry code: (i) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | C16H15Br2NO4S |
Mr | 477.17 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 10.8513 (4), 6.0019 (3), 26.7246 (7) |
β (°) | 90.232 (2) |
V (Å3) | 1740.52 (12) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 4.80 |
Crystal size (mm) | 0.32 × 0.21 × 0.20 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID S |
Absorption correction | Multi-scan (Blessing, 1995) |
Tmin, Tmax | 0.310, 0.383 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 44718, 5328, 4398 |
Rint | 0.097 |
(sin θ/λ)max (Å−1) | 0.716 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.099, 0.144, 1.39 |
No. of reflections | 5328 |
No. of parameters | 218 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.62, −0.49 |
Computer programs: CrystalClear (Rigaku, 2005), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
Br1—C15 | 1.926 (5) | S1—C5 | 1.746 (5) |
Br2—C16 | 1.933 (5) | N1—C8 | 1.388 (7) |
S1—O2 | 1.425 (4) | C12—C16 | 1.550 (7) |
S1—O1 | 1.428 (4) | C15—C16 | 1.546 (7) |
S1—N1 | 1.666 (4) | ||
O2—S1—O1 | 120.4 (3) | C10—C11—C15 | 117.3 (4) |
O2—S1—N1 | 103.3 (2) | C10—C11—C12 | 117.9 (4) |
O1—S1—N1 | 108.6 (3) | C11—C15—C16 | 89.2 (4) |
C13—C12—C16 | 112.0 (5) | C11—C15—Br1 | 119.0 (4) |
O4—C10—C11 | 107.9 (4) | C16—C15—Br1 | 119.5 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···O3i | 0.93 | 2.51 | 3.331 (7) | 148 |
C9—H9···O3i | 0.98 | 2.59 | 3.450 (7) | 147 |
Symmetry code: (i) x, y−1, z. |
Subscribe to Acta Crystallographica Section E: Crystallographic Communications
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- If you have already subscribed, you may need to register
Recently, we successfully used cyclooctatetraene as starting material for synthesis of various stereospecific cyclitol isomers and their aminocyclitol derivatives (Kara et al., 1994; Kelebekli et al., 2005, 2006). In addition, some aminocyclitols have shown interesting inhibitor activities towards glycosidases (Paul et al., 2002; Lysek & Vogel 2006). It is known that both cis- and trans-7,8-dichloro-cycloocta-1,3,5-triene are obtained by chlorination of cyclooctatetraene 1 (Reppe et al., 1948; Gözel et al., 1991;Şahin et al., 2006) (Scheme). For synthesis of the aminoconduritol derivative, we performed bromination of cyclooctatetraene 1 in ice bath (Boshe & Huisgen, 1965; Huisgen & Gasteiger, 1972). The bromination product 2 was heated in CCl4 at 323 K to form 3. The photooxygenation of 3 and its reduction of O—O bond with thiourea resulted in formation of 5 (Balci, 1981; Seçen et al., 1990; Kara & Balci, 2003; Kelebekli et al., 2005, 2006). Pd(0)-catalyzed reactions provide the selective entry to amino alcohols with various regio- and stereoselectivity. Recently, vinyl oxazolidone-2-one has been synthesized by stereoselective Pd(0)-catalyzed reaction with cis-2-alkene-1,4-diol in a single step (Trost et al., 1992; Trost & Van Vranken, 1993). Using this method, oxazolidinone 6 b was synthesized from 5 b. The exact configuration of compound 6 b was determined by 1H and 13C– NMR spectra and an X-ray diffraction analysis. The resolved structure provides information on the stereochemical course of the cis-brom atoms, namely, both bromine atoms are cis to each other. It is known that bromination is a stereoscpecific anti-addition. In the light of all this findings, one can conclude that formation of cis-bromide occurrs during bromination of cyclooctatetraene 1 as a minor product along with major trans adduct. In order to confirm this unexpected result again, the bromination of cyclooctatetraene 1 was repeated, and consecutive yield of cis-bromide was 5–10%.
The molecular structure of 6 b is shown in Fig. 1, and the bond lengths and angles are listed in Table 1. As reported earlier, after the bromination of cyclooctatetraene 1, cis-bromide product was observed (Boshe & Huisgen, 1965; Huisgen & Gasteiger, 1972), but this type of adducts was not investigated in detail.
Compound 6 b contains a central cyclohexene ring with a cyclobutane and oxazolidinone moieties fused to it. The Br atoms have cis stereochemistry, in which Br1—C15 [1.926 (5)] and Br2—C16 [(1.933 (3)]Å bond lengths are comparable with the Br—C (1.94 (1), 1.93 (1) Å) bond lengths in the dibromotetraacetate compound (Kara et al., 1994), but there the Br atoms have trans
configuration. Because of cis configuration of the Br atoms in compound 5 b, oxazolidinone moiety leads to formation of the only product 6 b. All the substituents, including the oxazolidinone moiety and the bromine atoms are on the same side of the bicycle (syn conformation). In addition to this, the cyclobutane and the oxazolidinone rings have trans stereochemistry. The cyclobutane moiety is appreciably folded with C—C distances in the range 1.542 (7)–1.551 (7) Å. Due to the strong electronegativity of the Cl atoms, this range is larger [1.534 (3)–1.567 (3) Å] in the (1SR,2SR,3SR,4RS,5RS,6RS,7SR,8RS)-7,8-Dichlorobicyclo[4.2.0] octa-2,3,4,5-tetrayl tetraacetate structure Şahin et al., 2006). Finally the cyclohexene ring adopts a half-chair conformation with puckering parameters QT=0.283 (5) Å, θ =52.0 (2)and φ=84.3 (4) °. Electron localization was also found at the C13—C14 bond with a length of 1.310 (7)Å which is appreciably shorter for cyclohexene C=C bond. Tosyl O1 atom does not depart from the phenyl ring plane. The O1—S1—C5 and O2—S1—C5 bond angles, as well as the O—S bond lengths are essentially equal as expected (Kelebekli et al., 2006).
The closest Br···C intermolecular distance is 3.428 (6)Å with no hydrogen atom directed even approximately along this line, so the Br atoms do not participate in hydrogen bonds. In the crystal structure Br2 atoms are facing one another along the c axis and the Br2···Br2 interatomic distance is 3.556Å within the van der Waals distance of 3.70 Å. C15—Br1···Pi(phenyl) noncovalent interactions contribute to the stability of the overall structure. The C-donor bond vectors are directed more closely towards the mid-point of an individual aromatic bond (Br1···C6=3.428, Br1···C7=3.458 Å) rather then the ring centroid (X) with Br1···X=3.440 (4)Å and C—Br···X=144.16 (16)°. Most important, the bromine does not coordinate to the benzene ring symmetrically in striking contrast to the coaxial (delocalized) model reported by Hassel & Stromme (1959). Instead, the bromine is positioned over the rim (not over the center) of the phenyl ring which corresponds to one of the highest electron density positions. Such experimental location of bromine is in good agreement with the data on noncovalent binding of halogens to aromatic donors (Vasilyev et al., 2001).
In the crystal structure the adjacent phenyl moieties are stacked opposed to each other. The distance between ring centroids is 3.893 (5)Å and the corresponding slip angle is 7.4°. The crystal structure is also stabilized by two weak intermolecular hydrogen bonds (Fig. 3).