Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103001574/gg1150sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103001574/gg1150Isup2.hkl |
CCDC reference: 211742
A solution of 6-cyanobenzothiazole (4 g, 25 mmol) in dry 2-(2-ethoxyethoxy)ethanol (60 ml) was cooled to 278 K and saturated with HCl. The flask was then stoppered and the contents stirred at room temperature for 2 d (until IR spectra indicated the disappearance of the nitrile peak). Excess HCl was removed from the suspension by a stream of N2. The reaction mixture was poured into 400 ml of dry ether, and crystals of imidoyl ether hydrochloride were filtered off, washed with dry ether and dried under reduced pressure over KOH. Imidoyl ether hydrochloride was poured into 150 ml of cold water with 20 ml of 20% K2CO3, and the free base was extracted with CHCl3. The solvent was evaporated, and the oil residue was dissolved in 100 ml of ethanol. The solution of NH4Cl (1.4 g, 26 mmol) in 25 ml of water was added to the ethanolic solution, and the mixture was heated under reflux for 5 h. After filtration (charcoal), the hot reaction mixture was left to stand at room temperature for 4 d. The title compound separated in colourless crystals [m.p. = 275°C, yield 3.94 g (68%)]. Spectroscopic analysis: IR (KBr, cm−1): 3265, 3080 (NH), 1679 (C═N); 1H NMR (300 MHz, DMSO-d6) δ: 9.67 (s, 1H, H-2), 9.41 (br s, 4H, H—NH, disappeared with D2O), 8.74 (d, 1H, J7,5 = 1.7 Hz, H-7), 8.31 (d, 1H, J4,5 = 8.6 Hz, H-4), 7.95 (dd, 1H, J5,4 = 8.6 Hz, J5,4 = 1.8 Hz, H-5). 13C NMR (75 MHz, DMSO-d6) δ: 166.2 (s), 161.3 (d), 156.5 (s), 134.5 (s), 126.4 (d), 125.7 (s), 124.2 (d), 123.8 (d). Analysis: calculated for C8H8ClN3S·2H2O C 38.48, H 4.84, N 16.83, Cl 14.20%; found C 38.67, H 4.48, N 17.03, Cl 14.64%.
Intensities were corrected for Lorentz and polarization and absorption effects (Stoe & Cie, 1995). The structure was solved by direct methods. H atoms were found in the difference Fourier map and were refined isotropically, giving C—H distances in the range 0.91 (3)–0.96 (2) Å, O—H distances in the range 0.73 (5)–0.91 (4) Å and N—H distances in the range 0.81 (3)–0.85 (2) Å.
Data collection: STADI4 (Stoe & Cie, 1995); cell refinement: X-RED (Stoe & Cie, 1995); data reduction: X-RED (Stoe & Cie, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON98 (Spek, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
C8H8N3S+·Cl−·2H2O | Dx = 1.429 Mg m−3 |
Mr = 249.72 | Melting point: 548 K |
Orthorhombic, Pna21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2c -2n | Cell parameters from 60 reflections |
a = 16.9296 (9) Å | θ = 12.5–17.8° |
b = 9.3433 (5) Å | µ = 0.49 mm−1 |
c = 7.3389 (15) Å | T = 293 K |
V = 1160.9 (3) Å3 | Block, colourless |
Z = 4 | 0.47 × 0.42 × 0.22 mm |
F(000) = 520 |
Philips PW1100 (updated by STOE) diffractometer | 2945 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.034 |
Planar Graphite monochromator | θmax = 30.0°, θmin = 3.3° |
ω scans | h = −23→23 |
Absorption correction: Ψ scan X-RED (Stoe & Cie, 1995) | k = −13→13 |
Tmin = 0.792, Tmax = 0.893 | l = −10→10 |
4203 measured reflections | 4 standard reflections every 90 min |
3377 independent reflections | intensity decay: 4% |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | All H-atom parameters refined |
R[F2 > 2σ(F2)] = 0.032 | w = 1/[σ2(Fo2) + (0.0471P)2 + 0.0723P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.081 | (Δ/σ)max < 0.001 |
S = 1.06 | Δρmax = 0.25 e Å−3 |
3377 reflections | Δρmin = −0.20 e Å−3 |
185 parameters | Extinction correction: SHELXL97, Fc* = kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 0.083 (4) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983) |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.02 (6) |
C8H8N3S+·Cl−·2H2O | V = 1160.9 (3) Å3 |
Mr = 249.72 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 16.9296 (9) Å | µ = 0.49 mm−1 |
b = 9.3433 (5) Å | T = 293 K |
c = 7.3389 (15) Å | 0.47 × 0.42 × 0.22 mm |
Philips PW1100 (updated by STOE) diffractometer | 2945 reflections with I > 2σ(I) |
Absorption correction: Ψ scan X-RED (Stoe & Cie, 1995) | Rint = 0.034 |
Tmin = 0.792, Tmax = 0.893 | 4 standard reflections every 90 min |
4203 measured reflections | intensity decay: 4% |
3377 independent reflections |
R[F2 > 2σ(F2)] = 0.032 | All H-atom parameters refined |
wR(F2) = 0.081 | Δρmax = 0.25 e Å−3 |
S = 1.06 | Δρmin = −0.20 e Å−3 |
3377 reflections | Absolute structure: Flack (1983) |
185 parameters | Absolute structure parameter: 0.02 (6) |
1 restraint |
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. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Cl | 0.51091 (2) | 0.31217 (5) | 0.39859 (8) | 0.04496 (12) | |
N1 | 0.79005 (10) | 0.30764 (15) | 0.1236 (2) | 0.0438 (3) | |
C1 | 0.86375 (13) | 0.30760 (18) | 0.0754 (3) | 0.0455 (4) | |
S | 0.90695 (2) | 0.47046 (5) | 0.02443 (7) | 0.04415 (12) | |
C2 | 0.81749 (9) | 0.55165 (16) | 0.0712 (2) | 0.0335 (3) | |
C3 | 0.79721 (9) | 0.69579 (15) | 0.0596 (2) | 0.0337 (3) | |
C4 | 0.72051 (9) | 0.73514 (16) | 0.1035 (2) | 0.0317 (3) | |
C5 | 0.66498 (9) | 0.63239 (18) | 0.1604 (2) | 0.0367 (3) | |
C6 | 0.68528 (11) | 0.48995 (19) | 0.1721 (3) | 0.0394 (3) | |
C7 | 0.76184 (10) | 0.44770 (16) | 0.1244 (2) | 0.0349 (3) | |
C8 | 0.69649 (9) | 0.88729 (17) | 0.0880 (2) | 0.0347 (3) | |
N2 | 0.74765 (11) | 0.98737 (16) | 0.1322 (2) | 0.0424 (3) | |
N3 | 0.62544 (9) | 0.91850 (17) | 0.0301 (3) | 0.0434 (3) | |
O1 | 0.90985 (10) | 0.92882 (19) | 0.2589 (3) | 0.0576 (4) | |
O2 | 0.57384 (14) | 0.20048 (17) | 0.0155 (4) | 0.0705 (5) | |
H1 | 0.8971 (13) | 0.227 (3) | 0.068 (3) | 0.048 (6)* | |
H3 | 0.8363 (12) | 0.758 (3) | 0.017 (3) | 0.047 (5)* | |
H5 | 0.6120 (14) | 0.660 (2) | 0.192 (3) | 0.042 (5)* | |
H6 | 0.6527 (13) | 0.420 (3) | 0.215 (3) | 0.046 (6)* | |
H21 | 0.7921 (13) | 0.964 (2) | 0.177 (3) | 0.037 (5)* | |
H22 | 0.7352 (15) | 1.074 (3) | 0.120 (3) | 0.051 (6)* | |
H31 | 0.5958 (16) | 0.855 (3) | −0.003 (4) | 0.061 (8)* | |
H32 | 0.6107 (15) | 1.002 (3) | 0.027 (5) | 0.052 (6)* | |
H101 | 0.938 (2) | 0.910 (4) | 0.156 (5) | 0.078 (9)* | |
H102 | 0.929 (2) | 0.991 (5) | 0.300 (6) | 0.093 (12)* | |
H201 | 0.558 (2) | 0.225 (4) | 0.109 (5) | 0.067 (9)* | |
H202 | 0.5813 (16) | 0.264 (4) | −0.053 (4) | 0.068 (9)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl | 0.03552 (17) | 0.0478 (2) | 0.0516 (2) | 0.00226 (15) | 0.00166 (18) | 0.0037 (2) |
N1 | 0.0542 (9) | 0.0260 (6) | 0.0511 (9) | −0.0016 (6) | −0.0122 (7) | 0.0014 (5) |
C1 | 0.0574 (10) | 0.0296 (7) | 0.0493 (10) | 0.0069 (7) | −0.0104 (8) | −0.0015 (6) |
S | 0.04013 (19) | 0.03467 (18) | 0.0576 (3) | 0.00547 (15) | 0.00139 (19) | −0.00148 (19) |
C2 | 0.0350 (6) | 0.0282 (6) | 0.0373 (8) | −0.0025 (5) | −0.0036 (5) | −0.0012 (5) |
C3 | 0.0331 (6) | 0.0262 (6) | 0.0417 (9) | −0.0038 (5) | 0.0019 (6) | −0.0003 (5) |
C4 | 0.0342 (6) | 0.0256 (6) | 0.0351 (7) | −0.0026 (5) | −0.0029 (6) | −0.0008 (5) |
C5 | 0.0315 (7) | 0.0359 (7) | 0.0428 (8) | −0.0054 (6) | −0.0010 (6) | 0.0021 (6) |
C6 | 0.0386 (7) | 0.0330 (7) | 0.0466 (9) | −0.0115 (6) | −0.0049 (7) | 0.0055 (7) |
C7 | 0.0417 (7) | 0.0266 (6) | 0.0363 (8) | −0.0055 (6) | −0.0077 (6) | 0.0018 (5) |
C8 | 0.0387 (7) | 0.0299 (6) | 0.0356 (7) | 0.0018 (6) | 0.0044 (6) | −0.0014 (6) |
N2 | 0.0472 (8) | 0.0252 (6) | 0.0547 (9) | −0.0017 (6) | −0.0005 (7) | −0.0020 (6) |
N3 | 0.0415 (6) | 0.0349 (6) | 0.0540 (8) | 0.0069 (6) | −0.0027 (7) | −0.0026 (7) |
O1 | 0.0595 (9) | 0.0531 (9) | 0.0603 (10) | −0.0125 (7) | −0.0017 (7) | −0.0139 (7) |
O2 | 0.1033 (15) | 0.0359 (7) | 0.0724 (12) | −0.0017 (7) | 0.0238 (11) | −0.0056 (9) |
S—C1 | 1.7292 (19) | C6—C7 | 1.399 (3) |
S—C2 | 1.7283 (16) | C6—H6 | 0.91 (3) |
N1—C1 | 1.297 (3) | C8—N3 | 1.309 (2) |
N1—C7 | 1.393 (2) | C8—N2 | 1.315 (2) |
C1—H1 | 0.95 (3) | N2—H21 | 0.85 (2) |
C2—C3 | 1.392 (2) | N2—H22 | 0.84 (3) |
C2—C7 | 1.408 (2) | N3—H31 | 0.82 (3) |
C3—C4 | 1.388 (2) | N3—H32 | 0.82 (3) |
C3—H3 | 0.93 (2) | O1—H101 | 0.91 (4) |
C4—C5 | 1.407 (2) | O1—H102 | 0.73 (4) |
C4—C8 | 1.483 (2) | O2—H201 | 0.77 (4) |
C5—C6 | 1.377 (2) | O2—H202 | 0.79 (4) |
C5—H5 | 0.96 (2) | ||
C1—S—C2 | 88.43 (9) | C3—C4—C8 | 119.51 (13) |
S—C2—C3 | 128.93 (12) | C5—C4—C8 | 119.59 (14) |
S—C2—C7 | 109.79 (12) | C4—C5—C6 | 120.74 (15) |
S—C1—N1 | 117.76 (13) | C6—C5—H5 | 118.3 (14) |
C1—N1—C7 | 109.34 (14) | C4—C5—H5 | 120.9 (14) |
N1—C7—C2 | 114.67 (15) | C5—C6—C7 | 119.22 (15) |
N1—C7—C6 | 125.70 (15) | C5—C6—H6 | 124.2 (15) |
N2—C8—N3 | 121.80 (16) | C7—C6—H6 | 116.5 (15) |
N2—C8—C4 | 118.81 (15) | C2—C7—C6 | 119.63 (14) |
N3—C8—C4 | 119.38 (15) | C8—N2—H21 | 119.5 (14) |
N1—C1—H1 | 126.2 (15) | C8—N2—H22 | 119.6 (18) |
S—C1—H1 | 116.0 (15) | H21—N2—H22 | 121 (2) |
C3—C2—C7 | 121.27 (15) | C8—N3—H31 | 120 (2) |
C2—C3—C4 | 118.21 (13) | C8—N3—H32 | 120.1 (18) |
C4—C3—H3 | 125.3 (14) | H31—N3—H32 | 120 (3) |
C2—C3—H3 | 116.4 (15) | H101—O1—H102 | 105 (4) |
C3—C4—C5 | 120.90 (14) | H201—O2—H202 | 113 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H21···O1 | 0.85 (2) | 2.11 (2) | 2.950 (3) | 171 (2) |
N2—H22···N1i | 0.84 (3) | 2.37 (3) | 3.078 (2) | 142 (2) |
N3—H31···Clii | 0.81 (3) | 2.49 (3) | 3.3023 (18) | 171 (3) |
N3—H32···O2i | 0.82 (3) | 1.96 (3) | 2.778 (2) | 179 (4) |
O1—H101···Cliii | 0.91 (4) | 2.27 (3) | 3.159 (2) | 165 (3) |
O1—H102···Cliv | 0.73 (5) | 2.41 (4) | 3.136 (2) | 170 (3) |
O2—H201···Cl | 0.77 (4) | 2.41 (4) | 3.183 (3) | 177.4 (17) |
O2—H202···O1v | 0.79 (3) | 2.07 (3) | 2.859 (3) | 175 (3) |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, −y+1, z−1/2; (iii) −x+3/2, y+1/2, z−1/2; (iv) x+1/2, −y+3/2, z; (v) −x+3/2, y−1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C8H8N3S+·Cl−·2H2O |
Mr | 249.72 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 293 |
a, b, c (Å) | 16.9296 (9), 9.3433 (5), 7.3389 (15) |
V (Å3) | 1160.9 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.49 |
Crystal size (mm) | 0.47 × 0.42 × 0.22 |
Data collection | |
Diffractometer | Philips PW1100 (updated by STOE) diffractometer |
Absorption correction | Ψ scan X-RED (Stoe & Cie, 1995) |
Tmin, Tmax | 0.792, 0.893 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4203, 3377, 2945 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 0.704 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.081, 1.06 |
No. of reflections | 3377 |
No. of parameters | 185 |
No. of restraints | 1 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.25, −0.20 |
Absolute structure | Flack (1983) |
Absolute structure parameter | 0.02 (6) |
Computer programs: STADI4 (Stoe & Cie, 1995), X-RED (Stoe & Cie, 1995), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON98 (Spek, 1990).
S—C1 | 1.7292 (19) | C3—C4 | 1.388 (2) |
S—C2 | 1.7283 (16) | C4—C5 | 1.407 (2) |
N1—C1 | 1.297 (3) | C4—C8 | 1.483 (2) |
N1—C7 | 1.393 (2) | C5—C6 | 1.377 (2) |
C2—C3 | 1.392 (2) | C6—C7 | 1.399 (3) |
C2—C7 | 1.408 (2) | ||
C1—S—C2 | 88.43 (9) | N1—C7—C2 | 114.67 (15) |
S—C2—C3 | 128.93 (12) | N1—C7—C6 | 125.70 (15) |
S—C2—C7 | 109.79 (12) | N2—C8—N3 | 121.80 (16) |
S—C1—N1 | 117.76 (13) | N2—C8—C4 | 118.81 (15) |
C1—N1—C7 | 109.34 (14) | N3—C8—C4 | 119.38 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H21···O1 | 0.85 (2) | 2.11 (2) | 2.950 (3) | 171 (2) |
N2—H22···N1i | 0.84 (3) | 2.37 (3) | 3.078 (2) | 142 (2) |
N3—H31···Clii | 0.81 (3) | 2.49 (3) | 3.3023 (18) | 171 (3) |
N3—H32···O2i | 0.82 (3) | 1.96 (3) | 2.778 (2) | 179 (4) |
O1—H101···Cliii | 0.91 (4) | 2.27 (3) | 3.159 (2) | 165 (3) |
O1—H102···Cliv | 0.73 (5) | 2.41 (4) | 3.136 (2) | 170 (3) |
O2—H201···Cl | 0.77 (4) | 2.41 (4) | 3.183 (3) | 177.4 (17) |
O2—H202···O1v | 0.79 (3) | 2.07 (3) | 2.859 (3) | 175 (3) |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, −y+1, z−1/2; (iii) −x+3/2, y+1/2, z−1/2; (iv) x+1/2, −y+3/2, z; (v) −x+3/2, y−1/2, z−1/2. |
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Small and simple heterocyclic structures often exhibit complex biological properties. Substituted benzothiazoles show biological activities including anti-tumor activity (Goldfarb et al., 1999), anti-infective and anti-fungal activity (Sener et al., 2000), and anti-helmintic activity (Nadkarn et al., 2000). In order to find new potent anti-tumor benzothiazole compounds (Racanè et al., 2001), we have introduced an amidino group into the benzothiazole moiety. This report describes the synthesis and crystal structure of a new cationic compound, benzo-1,3-thiazole-6-carboxamidinium chloride dihydrate, (I). Substituted benzothiazoles that are not bound to a metal are rare.
As depicted in the reaction Scheme, the starting compound was 6-cyanobenzothiazole (Boggust & Cocker, 1949). The conversion of the cyano function into the amidino function was achieved using the Pinner method (Boyd, 1991). The imidoyl ether hydrochloride that was generated as an intermediate product was converted into the free base with potassium carbonate and was then converted with ammonium chloride into the desired 6-amidinobenzothiazole hydrochloride (I).
The structure comprises benzo-1,3-thiazole-6-carboxamidinium cations, chloride anions and water molecules (Fig 1); pertinent bond lengths and angles are given in Table 1. The plane calculated through the atoms of the 1,3-benzothiazole moiety shows that it is planar, with the largest deviation from the plane being that of atom C6 [0.023 (2) Å.] However, the entire benzo-1,3-thiazole-6-carboxamidinium cation is not planar, since the plane through the 6-amidino group is inclined to that through the 1,3-benzothiazole moiety by 36.71 (9)°. The C—C differences within the benzene ring are usual for such fused rings. The bond angle around the S atom is within the range found in five-membered rings of other substituted benzothiazole derivatives (Davidović et al., 1999; Popović et al., 2001, Popović et al., 2002). The hydrogen-bond pattern is very interesting, since all N/H and O/H donor atoms are involved in the hydrogen bonding to the acceptor atoms: endocyclic N atoms, the Cl ion and water O atoms. Water molecules have an important role since they form six out of the eight hydrogen bonds that interconnect the ions and molecules into a three-dimensional network (Table 2).