Acta Cryst. (2012). E68, o1198 [ doi:10.1107/S1600536812012433 ]
The asymmetric unit of the title compound, C2H3N3OS, contains three independent molecules which are essentially planar, with r.m.s. deviations of 0.011 (2)-0.027 (2) Å from the mean plane defined by the seven non-H atoms. In the crystal, N-H
N and N-HO hydrogen bonds link the molecules into a sheet parallel to the (111) plane.
Synthesis of 5-amino-2-ethoxy-1,3,4-thiadiazole: Ethyl thiocarbazate (4.8 g, 0.04 mol) was dissolved in 24 ml of 2 N NaOH at 10 °C. Cyanogen bromide (4.2 g, 0.04 mol) dissolved in 20 ml of ethanol was added to the above solution keeping the temperature below 10 °C during 45 minutes. The solid product (4.1 g, 71%) was collected by filtration. To obtain the analytical sample the product was recrystallized from ethanol. m.p. 200–202 °C; IR (KBr, cm-1) 3300 (NH), 3150 (NH), 3000 (CH), 2950 (CH), 1620 (C=O), 1580 (C=N); 1H NMR (DMSO-d6, p.p.m.) 6.65 (2H, b, NH2), 4.25 (2H, q, CH2), 1.29 (3H, t, CH3); 13C NMR (DMSO-d6, p.p.m.) 164.85 (C=N), 162.18 (C—O), 67.48 (CH2), 14.35 (CH3); Anal. Calcd. For C4H7N3OS: C 33.09, H 4.86, N 28.94. Found: C 33.71, H 4.94, N 28.50.
Synthesis of title compound: 5-Amino-2-ethoxy-1,3,4-thiadiazole (5 g, 34.5 mmol) was dissolved in 50 ml of dioxane and 3.5 ml of c-HCl was added. The reaction mixture was refluxed for 4.5 h. The solvent was distilled off under reduced pressure. The residue product was washed with ether (3.7 g, 92.5%). To obtain the analytical sample the product was recrystallized from water. Recrystallization from DMSO afforded the colorless crystals suitable for X-ray diffraction. m.p. 176–178 °C; IR (KBr, cm-1) 3450 (NH), 3150 (NH), 3100, 3000, 2900 (CH), 1700 (C=O), 1610, 1500 (C=N); 1H NMR (DMSO-d6, p.p.m.) 11.3 (1H, b, NH), 6.4 (2H, b, NH2; 13C NMR (DMSO-d6, p.p.m.) 169.4 (C=N), 153.0 (C=O); Anal. Calcd. For C2H3N3OS: C 20.51, H 2.58, N 35.88, S 27.37. Found: C 20.19, H 2.65, N 34.28, S 27.22.
H atoms of the NH and NH2 groups were located in a difference Fourier map and refined freely [refined distances = 0.79 (2)–0.94 (2) Å].
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](./is5096fig1thm.gif)
| Fig. 1. Molecular structure of the title compound, showing the atom-numbering scheme and 30% probability ellipsoids. Intermolecular N—H···N hydrogen bonds are indicated by dashed lines. |
![[Figure 2]](./is5096fig2thm.gif)
| Fig. 2. Part of the crystal structure of the title compound, showing molecules linked by intermolecular N—H···N and N—H···O hydrogen bonds (dashed lines). |
| C2H3N3OS | Z = 6 |
| Mr = 117.13 | F(000) = 360 |
| Triclinic, P1 | Dx = 1.694 Mg m−3 |
| Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
| a = 7.2860 (2) Å | Cell parameters from 5437 reflections |
| b = 10.2982 (3) Å | θ = 2.2–26.1° |
| c = 10.7727 (3) Å | µ = 0.57 mm−1 |
| α = 63.721 (3)° | T = 296 K |
| β = 73.122 (2)° | Block, colourless |
| γ = 76.737 (2)° | 0.15 × 0.1 × 0.05 mm |
| V = 688.74 (3) Å3 |
| Bruker SMART CCD area-detector diffractometer | 2526 reflections with I > 2σ(I) |
| Graphite monochromator | Rint = 0.055 |
| φ and ω scans | θmax = 28.3°, θmin = 2.2° |
| Absorption correction: multi-scan (SADABS; Bruker, 2002) | h = −9→9 |
| Tmin = 0.93, Tmax = 0.97 | k = −13→13 |
| 23857 measured reflections | l = −14→14 |
| 3433 independent reflections |
| Refinement on F2 | Primary atom site location: structure-invariant direct methods |
| Least-squares matrix: full | Secondary atom site location: difference Fourier map |
| R[F2 > 2σ(F2)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.080 | All H-atom parameters refined |
| S = 0.94 | w = 1/[σ2(Fo2) + (0.0423P)2] where P = (Fo2 + 2Fc2)/3 |
| 3433 reflections | (Δ/σ)max < 0.001 |
| 226 parameters | Δρmax = 0.30 e Å−3 |
| 0 restraints | Δρmin = −0.26 e Å−3 |
| C2H3N3OS | γ = 76.737 (2)° |
| Mr = 117.13 | V = 688.74 (3) Å3 |
| Triclinic, P1 | Z = 6 |
| a = 7.2860 (2) Å | Mo Kα radiation |
| b = 10.2982 (3) Å | µ = 0.57 mm−1 |
| c = 10.7727 (3) Å | T = 296 K |
| α = 63.721 (3)° | 0.15 × 0.1 × 0.05 mm |
| β = 73.122 (2)° |
| Bruker SMART CCD area-detector diffractometer | 3433 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2002) | 2526 reflections with I > 2σ(I) |
| Tmin = 0.93, Tmax = 0.97 | Rint = 0.055 |
| 23857 measured reflections | θmax = 28.3° |
| R[F2 > 2σ(F2)] = 0.031 | All H-atom parameters refined |
| wR(F2) = 0.080 | Δρmax = 0.30 e Å−3 |
| S = 0.94 | Δρmin = −0.26 e Å−3 |
| 3433 reflections | Absolute structure: ? |
| 226 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | ||
| S1 | 0.86165 (6) | −0.07773 (5) | −0.06572 (4) | 0.03647 (13) | |
| C2 | 0.7587 (2) | 0.10880 (18) | −0.13554 (16) | 0.0339 (4) | |
| N3 | 0.6466 (2) | 0.13649 (15) | −0.02585 (14) | 0.0329 (3) | |
| H3 | 0.580 (3) | 0.219 (2) | −0.0362 (19) | 0.044 (5)* | |
| N4 | 0.62764 (19) | 0.02538 (14) | 0.10886 (13) | 0.0303 (3) | |
| C5 | 0.7333 (2) | −0.09181 (17) | 0.10313 (16) | 0.0289 (3) | |
| O6 | 0.7853 (2) | 0.19397 (15) | −0.26078 (12) | 0.0517 (4) | |
| N7 | 0.7416 (3) | −0.21857 (17) | 0.21825 (17) | 0.0472 (4) | |
| H7A | 0.825 (3) | −0.291 (3) | 0.210 (2) | 0.072 (7)* | |
| H7B | 0.672 (3) | −0.224 (2) | 0.297 (2) | 0.052 (6)* | |
| S8 | 0.15828 (7) | 0.02436 (5) | 0.59226 (4) | 0.03889 (13) | |
| C9 | 0.3260 (2) | −0.05097 (18) | 0.47618 (16) | 0.0338 (4) | |
| N10 | 0.3484 (2) | 0.05559 (15) | 0.34594 (14) | 0.0353 (3) | |
| H10 | 0.439 (3) | 0.047 (2) | 0.262 (2) | 0.065 (6)* | |
| N11 | 0.2481 (2) | 0.19183 (14) | 0.32756 (13) | 0.0354 (3) | |
| C12 | 0.1437 (2) | 0.19073 (18) | 0.44702 (16) | 0.0348 (4) | |
| O13 | 0.40594 (19) | −0.17651 (13) | 0.51031 (13) | 0.0485 (3) | |
| N14 | 0.0375 (3) | 0.3114 (2) | 0.4619 (2) | 0.0592 (5) | |
| H14A | −0.048 (3) | 0.297 (2) | 0.536 (3) | 0.070 (7)* | |
| H14B | 0.019 (3) | 0.387 (2) | 0.386 (2) | 0.050 (6)* | |
| S15 | 0.23799 (7) | 0.66689 (5) | −0.15169 (5) | 0.04302 (14) | |
| C16 | 0.1723 (2) | 0.55543 (18) | 0.03347 (17) | 0.0363 (4) | |
| N17 | 0.2688 (2) | 0.42407 (15) | 0.05437 (15) | 0.0353 (3) | |
| H17 | 0.262 (3) | 0.352 (2) | 0.138 (2) | 0.053 (6)* | |
| N18 | 0.3933 (2) | 0.40035 (14) | −0.06009 (13) | 0.0354 (3) | |
| C19 | 0.3895 (2) | 0.51734 (17) | −0.17336 (17) | 0.0356 (4) | |
| O20 | 0.0594 (2) | 0.59341 (14) | 0.12439 (14) | 0.0537 (4) | |
| N21 | 0.4930 (3) | 0.5249 (2) | −0.30232 (18) | 0.0651 (6) | |
| H21A | 0.492 (4) | 0.606 (3) | −0.363 (3) | 0.081 (8)* | |
| H21B | 0.566 (3) | 0.455 (3) | −0.304 (2) | 0.071 (8)* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| S1 | 0.0365 (2) | 0.0374 (2) | 0.0315 (2) | 0.00386 (18) | 0.00096 (17) | −0.01947 (18) |
| C2 | 0.0319 (9) | 0.0371 (9) | 0.0289 (8) | −0.0040 (7) | −0.0003 (7) | −0.0139 (7) |
| N3 | 0.0386 (8) | 0.0250 (7) | 0.0254 (6) | 0.0032 (6) | −0.0008 (6) | −0.0089 (6) |
| N4 | 0.0345 (7) | 0.0262 (7) | 0.0233 (6) | 0.0000 (6) | −0.0004 (5) | −0.0091 (5) |
| C5 | 0.0290 (8) | 0.0292 (8) | 0.0274 (7) | −0.0007 (7) | −0.0024 (6) | −0.0139 (7) |
| O6 | 0.0631 (9) | 0.0485 (8) | 0.0246 (6) | −0.0049 (7) | 0.0027 (6) | −0.0064 (6) |
| N7 | 0.0625 (12) | 0.0306 (9) | 0.0324 (8) | 0.0104 (8) | −0.0046 (8) | −0.0096 (7) |
| S8 | 0.0458 (3) | 0.0368 (2) | 0.02102 (19) | −0.00454 (19) | 0.00086 (17) | −0.00531 (17) |
| C9 | 0.0375 (9) | 0.0317 (9) | 0.0270 (8) | −0.0028 (7) | −0.0059 (7) | −0.0084 (7) |
| N10 | 0.0412 (8) | 0.0293 (7) | 0.0241 (6) | 0.0039 (6) | −0.0013 (6) | −0.0080 (6) |
| N11 | 0.0412 (8) | 0.0276 (7) | 0.0224 (6) | 0.0029 (6) | 0.0011 (6) | −0.0052 (6) |
| C12 | 0.0366 (9) | 0.0310 (9) | 0.0261 (8) | −0.0022 (7) | 0.0009 (7) | −0.0078 (7) |
| O13 | 0.0601 (9) | 0.0290 (7) | 0.0423 (7) | 0.0049 (6) | −0.0128 (6) | −0.0056 (6) |
| N14 | 0.0692 (13) | 0.0386 (10) | 0.0393 (10) | 0.0088 (9) | 0.0126 (9) | −0.0111 (8) |
| S15 | 0.0533 (3) | 0.0232 (2) | 0.0365 (2) | 0.00734 (19) | −0.0052 (2) | −0.00628 (18) |
| C16 | 0.0386 (10) | 0.0298 (9) | 0.0342 (9) | 0.0008 (7) | −0.0040 (7) | −0.0121 (7) |
| N17 | 0.0417 (9) | 0.0258 (7) | 0.0255 (7) | 0.0029 (6) | −0.0009 (6) | −0.0061 (6) |
| N18 | 0.0423 (8) | 0.0241 (7) | 0.0267 (7) | 0.0036 (6) | 0.0006 (6) | −0.0074 (6) |
| C19 | 0.0428 (10) | 0.0240 (8) | 0.0305 (8) | 0.0000 (7) | −0.0020 (7) | −0.0083 (7) |
| O20 | 0.0561 (9) | 0.0453 (8) | 0.0474 (7) | 0.0072 (6) | 0.0046 (6) | −0.0238 (6) |
| N21 | 0.0938 (16) | 0.0328 (10) | 0.0314 (9) | 0.0067 (10) | 0.0134 (9) | −0.0036 (8) |
| S1—C5 | 1.7449 (15) | N10—H10 | 0.98 (2) |
| S1—C2 | 1.7905 (17) | N11—C12 | 1.2874 (19) |
| C2—O6 | 1.2270 (19) | C12—N14 | 1.354 (2) |
| C2—N3 | 1.333 (2) | N14—H14A | 0.83 (2) |
| N3—N4 | 1.3857 (18) | N14—H14B | 0.86 (2) |
| N3—H3 | 0.854 (19) | S15—C19 | 1.7419 (17) |
| N4—C5 | 1.2905 (19) | S15—C16 | 1.7876 (17) |
| C5—N7 | 1.349 (2) | C16—O20 | 1.2298 (19) |
| N7—H7A | 0.87 (2) | C16—N17 | 1.327 (2) |
| N7—H7B | 0.84 (2) | N17—N18 | 1.3853 (18) |
| S8—C12 | 1.7419 (16) | N17—H17 | 0.88 (2) |
| S8—C9 | 1.7874 (17) | N18—C19 | 1.2821 (19) |
| C9—O13 | 1.2264 (19) | C19—N21 | 1.352 (2) |
| C9—N10 | 1.336 (2) | N21—H21A | 0.80 (3) |
| N10—N11 | 1.3817 (18) | N21—H21B | 0.79 (2) |
| C5—S1—C2 | 88.70 (7) | C12—N11—N10 | 110.16 (13) |
| O6—C2—N3 | 126.79 (16) | N11—C12—N14 | 123.00 (15) |
| O6—C2—S1 | 126.30 (13) | N11—C12—S8 | 115.37 (12) |
| N3—C2—S1 | 106.90 (12) | N14—C12—S8 | 121.53 (13) |
| C2—N3—N4 | 119.16 (14) | C12—N14—H14A | 116.1 (16) |
| C2—N3—H3 | 122.2 (13) | C12—N14—H14B | 117.8 (13) |
| N4—N3—H3 | 118.5 (13) | H14A—N14—H14B | 118 (2) |
| C5—N4—N3 | 109.74 (12) | C19—S15—C16 | 88.49 (8) |
| N4—C5—N7 | 122.96 (15) | O20—C16—N17 | 126.47 (16) |
| N4—C5—S1 | 115.48 (12) | O20—C16—S15 | 126.48 (13) |
| N7—C5—S1 | 121.54 (12) | N17—C16—S15 | 107.05 (12) |
| C5—N7—H7A | 118.8 (15) | C16—N17—N18 | 119.02 (14) |
| C5—N7—H7B | 119.4 (14) | C16—N17—H17 | 122.9 (13) |
| H7A—N7—H7B | 122 (2) | N18—N17—H17 | 118.0 (13) |
| C12—S8—C9 | 88.73 (7) | C19—N18—N17 | 109.75 (13) |
| O13—C9—N10 | 126.70 (16) | N18—C19—N21 | 122.74 (16) |
| O13—C9—S8 | 126.29 (13) | N18—C19—S15 | 115.68 (12) |
| N10—C9—S8 | 107.01 (12) | N21—C19—S15 | 121.57 (13) |
| C9—N10—N11 | 118.72 (13) | C19—N21—H21A | 113.9 (17) |
| C9—N10—H10 | 125.0 (12) | C19—N21—H21B | 116.2 (17) |
| N11—N10—H10 | 116.1 (12) | H21A—N21—H21B | 128 (2) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N3—H3···N18 | 0.854 (19) | 2.004 (19) | 2.8516 (19) | 171.9 (18) |
| N7—H7A···O20i | 0.87 (2) | 2.07 (2) | 2.907 (2) | 160 (2) |
| N10—H10···N4 | 0.98 (2) | 1.88 (2) | 2.8558 (19) | 175.7 (18) |
| N14—H14A···O6ii | 0.83 (2) | 2.10 (2) | 2.897 (2) | 162 (2) |
| N17—H17···N11 | 0.88 (2) | 1.97 (2) | 2.8424 (18) | 179 (4) |
| N21—H21A···O13iii | 0.80 (3) | 2.10 (3) | 2.878 (2) | 163 (2) |
| Symmetry codes: (i) x+1, y−1, z; (ii) x−1, y, z+1; (iii) x, y+1, z−1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N3—H3···N18 | 0.854 (19) | 2.004 (19) | 2.8516 (19) | 171.9 (18) |
| N7—H7A···O20i | 0.87 (2) | 2.07 (2) | 2.907 (2) | 160 (2) |
| N10—H10···N4 | 0.98 (2) | 1.88 (2) | 2.8558 (19) | 175.7 (18) |
| N14—H14A···O6ii | 0.83 (2) | 2.10 (2) | 2.897 (2) | 162 (2) |
| N17—H17···N11 | 0.88 (2) | 1.97 (2) | 2.8424 (18) | 179 (4) |
| N21—H21A···O13iii | 0.80 (3) | 2.10 (3) | 2.878 (2) | 163 (2) |
| Symmetry codes: (i) x+1, y−1, z; (ii) x−1, y, z+1; (iii) x, y+1, z−1. |
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5-Amino-2H-1,2,4-thiadiazolin-3-one heterocycle is an analog of cytosine (Parkanyi et al., 1989). Derivatives of 5-amino-2H-1,2,4-thiadiazolin-3-one have recently attracted attention on the antibacterial activity, potential carcinogenicity, and kinase inhibitor activity (Castro et al., 2008; Cho, Ra et al., 1996; Ra, Cho, Moon & Kang, 1998). 5-Amino-3H-1,3,4-thiadiazolin-2-one is an isomer of 5-amino-2H-1,2,4-thiadiazolin-3-one, which has become an attractive moiety due to potential biological activities (Cho, Cho, Ra, Moon et al., 1996; Ra, Cho & Cho 1998).
In (I), three independent but similar molecules, which are linked by the intermolecular N—H···N hydrogen bonds (Fig. 1), comprise the asymmetric unit. The 1,3,4-thiadiazolin-2-one units are almost planar with r.m.s. deviations of 0.011 (2)–0.027 (2) Å from the corresponding least-squares plane defined by the seven constituent atoms. The bond distance of N4—C5 [1.291 (2) Å; N11—C12, 1.287 (2) Å; N18—C19, 1.282 (2) Å] is shorter than that of C2—N3 [1.333 (2) Å; C9—N10, 1.336 (2) Å; C16—N17, 1.327 Å], which is consistent with double bond character. The crystal structure is stabilized by the intermolecular N—H···N and N—H···O hydrogen bonds, which link the molecules into a two-dimensional sheet parallel to the (111) plane (Table 1 and Fig. 2).