research communications
N-[(1S,2S)-2-aminocyclohexyl]-2,4,6-trimethylbenzenesulfonamide
ofaDepartment of Chemistry, Grand Valley State University, 1 Campus Dr., Allendale, MI 49401, USA, and bCenter for Crystallographic Research, Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
*Correspondence e-mail: ngassaf@gvsu.edu
The title compound, C15H24N2O2S, was synthesized via a between the enantiopure (1S,2S)-(+)-1,2-diaminocyclohexane and 2,4,6-trimethylbenzene-1-sulfonyl chloride. The cyclohexyl and phenyl substituents are oriented gauche around the sulfonamide S—N bond. In the crystal, molecules are linked via N—H⋯N hydrogen bonds, forming chains propagating along [100].
Keywords: crystal structure; sulfonamide; hydrogen bond; chiral compound.
CCDC reference: 1437453
1. Chemical context
Many ; Yan et al., 2006; Palakurthy & Mandal, 2011). The use of as catalysts in has also been reported (Lao et al., 2009; Feng et al., 2010; Jin et al., 2010). Through explicit hydrogen-bonding interactions with specific functional groups, the and stereoselectivity of a given substrate is enhanced.
have been reported as anticancer, anti-inflammatory, and antiviral agents (Navia, 2000Conjugate addition reactions of ; Rabalakos & Wulff, 2008; Lao et al., 2009; Sun et al., 2012; Zhou et al., 2014; Ruiz-Olalla et al., 2015; Yang et al., 2015). The of chiral primary amine organocatalysts with particular emphasis on the role of the N—H acidity and hydrogen bonding has also been investigated (Lao et al., 2009). Although the N—H acidity and hydrogen-bonding modes could have an effect on the of the organocatalysts, the nature of the substrate and reaction conditions could be more important. Asymmetric conjugate addition reactions of to nitroalkenes have also been reported as a convenient synthesis of γ-amino acids (Horne & Gellman, 2008; Wiesner et al., 2008; Chi et al., 2008).
and to nitroalkenes, catalyzed by chiral primary have been reported (Huang & Jacobsen, 2006In line with our research interest in the synthesis of heterogeneous foldamers (Hayen et al., 2004), we synthesized the title compound as a chiral organocatalyst for conjugate addition. This conjugate addition was then applied for the synthesis of γ-amino acids, which have been shown to be interesting foldamer building blocks (Horne & Gellman, 2008). Therefore, as the title compound is of interest in our ongoing effort on foldamer design and synthesis, we report here on the synthesis and of this chiral sulfonamide.
2. Structural commentary
The asymmetric part of the along with the atom-numbering scheme. The absolute stereochemistry of this chiral sulfonamide was confirmed by a of 0.00 (2) (Parsons et al., 2013). The cyclohexyl (C1–C6) and benzene (C7–C12) substituents are oriented gauche around the sulfonamide S—N bond, with a C1—N1—S1—C7 torsion angle of 70.4 (2)°. A weak intramolecular interaction is present between the amine H2A atom and the sp2-hybridized sulfonamide N1 atom (Table 1).
is shown in Fig. 1
|
As described in the Database survey section below, the structure of a racemic crystal of this compound has been reported (FAVHEP; Balsells, et al., 1998). In this crystal, there are two crystallographically unique molecules of the sulfonamide compound in the Here, the cyclohexyl and benzene substituents are oriented gauche around the S—N bond with torsion angles of 86.8 (8) and 69.1 (7)°. While we expected that there would be an intramolecular hydrogen bond in this crystal, in the model deposited in the CSD there are no intramolecular hydrogen bonds present between the amine N—H group and the sulfonamide N atom.
3. Supramolecular features
Molecules of the title compound are held together in the solid state by intermolecular hydrogen-bonding interactions between the donor sulfonamide N1—H1 and the acceptor amine N2 atoms (Table 1 and Fig. 2). These hydrogen bonds arrange molecules into supramolecular chains that are oriented along the [100] axis (Fig. 2). Weaker N2—H2B⋯O1(1 + x, y, z) interactions with an H2B⋯O1(1 + x, y, z) distance of 2.72 Å between the donor amine N2—H2B and the acceptor sulfonamide O1 atoms can also be noticed within this chain.
As for the racemic crystal FAVHEP, in the model deposited in the CSD there is one intermolecular hydrogen bond present between a donor sulfonamide N1—H1 and a nearby amine acceptor N atom [D⋯H = 0.860 (7) Å; H⋯A = 2.160 (8) Å; D⋯A = 3.011 (8) Å; D—H⋯A = 169.9 (5)°].
4. Database survey
The Cambridge Structural Database (CSD, Version 5.36, May 2015; Groom & Allen, 2014) contains 35 bearing a mesitylene group on the S atom. Of these, there are four structures where the substituent bonded to the sulfonamide N atom is an aliphatic six-membered ring. In structures RAWMAF (Hou et al., 2012) and ZIQPAS (Wu et al., 2014), the aminocyclohexane substituent is part of a larger fused-ring system. Interestingly, there are two structures with 1,2-diaminocyclohexane rings as the amide substituent. In structure OTOPAP (Schwarz et al., 2010), both of the trans-1,2-diaminocyclohexane ring are bonded to a mesitylsulfonamide group. Structure FAVHEP (Balsells et al., 1998) is the same as the title compound, but is present as a that crystallized in the P.
5. Synthesis and crystallization
To a stirred solution of (1S,2S)-(+)-1,2-diaminocyclohexane (0.77 g, 6.74 mmol) in 5 ml of CH2Cl2 at 273 K was added a solution of 2,4,6-trimethylbenzene-1-sulfonyl chloride (0.44 g, 2.01 mmol) in 5 ml CH2Cl2. After the addition was complete (20 min), the mixture was allowed to warm to room temperature and stirred overnight. The reaction mixture was washed with H2O (3 × 25 ml) and the aqueous layer was back-extracted with CH2Cl2 (20 ml). The combined organic extracts were dried over Na2SO4 and the solvent was removed under reduced pressure. The residue was purified by over silica gel (CH2Cl2/EtOAc 1:1 v/v) to afford a pale-yellow–white solid (yield: 0.46 g, 78%). Part of the purified product was redissolved in CH2Cl2 and after slow evaporation for several days, white large chunky crystals (stained yellow) were formed that were suitable for analysis by X-ray diffraction (m.p. 406–407 K).
6. Refinement
Crystal data, data collection and structure . The positions of all non-polar H atoms were calculated geometrically and refined to ride on their parent atoms, with Uiso(H) = 1.2Ueq(C) for methine, methylene and and Uiso(H) = 1.5Ueq(C) for methyl groups. H atoms bonded directly to N atoms (H1, H2A and H2B) were located in difference-Fourier maps and refined isotropically.
details are summarized in Table 2Supporting information
CCDC reference: 1437453
https://doi.org/10.1107/S205698901502191X/gk2646sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901502191X/gk2646Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S205698901502191X/gk2646Isup3.cml
Data collection: APEX2 (Bruker, 2013); cell
SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009; Bourhis et al., 2015); software used to prepare material for publication: CrystalMaker (Palmer, 2007).C15H24N2O2S | Dx = 1.289 Mg m−3 |
Mr = 296.42 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 9968 reflections |
a = 6.5215 (4) Å | θ = 2.2–25.3° |
b = 10.0202 (6) Å | µ = 0.22 mm−1 |
c = 23.3660 (15) Å | T = 173 K |
V = 1526.89 (16) Å3 | Block, colourless |
Z = 4 | 0.37 × 0.20 × 0.15 mm |
F(000) = 640 |
Bruker APEXII CCD diffractometer | 2799 independent reflections |
Radiation source: sealed tube | 2667 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
Detector resolution: 8 pixels mm-1 | θmax = 25.4°, θmin = 1.7° |
φ and ω scans | h = −7→7 |
Absorption correction: multi-scan (SADABS; Bruker, 2014) | k = −12→12 |
Tmin = 0.706, Tmax = 0.745 | l = −28→28 |
25587 measured reflections |
Refinement on F2 | Hydrogen site location: mixed |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.029 | w = 1/[σ2(Fo2) + (0.0313P)2 + 0.5049P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.071 | (Δ/σ)max < 0.001 |
S = 1.06 | Δρmax = 0.19 e Å−3 |
2799 reflections | Δρmin = −0.21 e Å−3 |
196 parameters | Absolute structure: Flack parameter x determined using 1098 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
0 restraints | Absolute structure parameter: 0.00 (2) |
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 | ||
S1 | 0.39425 (9) | 0.81200 (6) | 0.62892 (2) | 0.03018 (16) | |
O1 | 0.2464 (3) | 0.72704 (19) | 0.65596 (8) | 0.0412 (4) | |
O2 | 0.3238 (3) | 0.93797 (17) | 0.60697 (8) | 0.0408 (5) | |
N1 | 0.5015 (3) | 0.7361 (2) | 0.57616 (9) | 0.0297 (5) | |
N2 | 0.9140 (3) | 0.6769 (2) | 0.54061 (8) | 0.0287 (4) | |
C1 | 0.5776 (3) | 0.5984 (2) | 0.58084 (9) | 0.0238 (5) | |
H1A | 0.6425 | 0.5872 | 0.6193 | 0.029* | |
C2 | 0.7442 (3) | 0.5816 (2) | 0.53502 (9) | 0.0234 (5) | |
H2 | 0.6780 | 0.5986 | 0.4971 | 0.028* | |
C3 | 0.8271 (3) | 0.4398 (2) | 0.53360 (10) | 0.0273 (5) | |
H3A | 0.9052 | 0.4225 | 0.5692 | 0.033* | |
H3B | 0.9228 | 0.4306 | 0.5009 | 0.033* | |
C4 | 0.6574 (4) | 0.3363 (2) | 0.52793 (10) | 0.0308 (5) | |
H4A | 0.7174 | 0.2457 | 0.5300 | 0.037* | |
H4B | 0.5902 | 0.3460 | 0.4902 | 0.037* | |
C5 | 0.4980 (4) | 0.3528 (2) | 0.57518 (11) | 0.0314 (5) | |
H5A | 0.3864 | 0.2871 | 0.5696 | 0.038* | |
H5B | 0.5624 | 0.3353 | 0.6128 | 0.038* | |
C6 | 0.4094 (4) | 0.4934 (2) | 0.57442 (10) | 0.0300 (5) | |
H6A | 0.3095 | 0.5031 | 0.6061 | 0.036* | |
H6B | 0.3356 | 0.5080 | 0.5379 | 0.036* | |
C7 | 0.5988 (4) | 0.8413 (2) | 0.67770 (9) | 0.0252 (5) | |
C8 | 0.7523 (4) | 0.9336 (2) | 0.66163 (9) | 0.0270 (5) | |
C9 | 0.9071 (4) | 0.9619 (2) | 0.69984 (10) | 0.0321 (5) | |
H9 | 1.0119 | 1.0225 | 0.6887 | 0.039* | |
C10 | 0.9154 (4) | 0.9054 (2) | 0.75383 (10) | 0.0340 (6) | |
C11 | 0.7662 (4) | 0.8131 (3) | 0.76822 (10) | 0.0346 (5) | |
H11 | 0.7724 | 0.7723 | 0.8049 | 0.042* | |
C12 | 0.6078 (4) | 0.7775 (2) | 0.73148 (9) | 0.0291 (5) | |
C13 | 0.7568 (5) | 1.0087 (2) | 0.60541 (10) | 0.0384 (6) | |
H13A | 0.7084 | 0.9502 | 0.5746 | 0.058* | |
H13B | 0.8974 | 1.0373 | 0.5972 | 0.058* | |
H13C | 0.6675 | 1.0871 | 0.6080 | 0.058* | |
C14 | 1.0799 (5) | 0.9459 (3) | 0.79566 (13) | 0.0532 (8) | |
H14A | 1.2117 | 0.9523 | 0.7757 | 0.080* | |
H14B | 1.0897 | 0.8789 | 0.8261 | 0.080* | |
H14C | 1.0452 | 1.0327 | 0.8124 | 0.080* | |
C15 | 0.4607 (5) | 0.6726 (3) | 0.75300 (12) | 0.0440 (7) | |
H15A | 0.3236 | 0.7116 | 0.7569 | 0.066* | |
H15B | 0.5071 | 0.6399 | 0.7903 | 0.066* | |
H15C | 0.4559 | 0.5983 | 0.7258 | 0.066* | |
H2A | 0.864 (5) | 0.754 (3) | 0.5537 (12) | 0.047 (8)* | |
H1 | 0.484 (5) | 0.768 (3) | 0.5458 (13) | 0.040 (8)* | |
H2B | 1.003 (5) | 0.645 (3) | 0.5683 (13) | 0.045 (8)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0271 (3) | 0.0327 (3) | 0.0307 (3) | 0.0072 (3) | 0.0005 (3) | −0.0065 (2) |
O1 | 0.0275 (8) | 0.0496 (11) | 0.0465 (10) | −0.0037 (8) | 0.0092 (8) | −0.0111 (8) |
O2 | 0.0427 (10) | 0.0387 (10) | 0.0410 (10) | 0.0196 (8) | −0.0057 (8) | −0.0067 (8) |
N1 | 0.0371 (11) | 0.0293 (11) | 0.0228 (10) | 0.0109 (9) | −0.0014 (9) | −0.0010 (9) |
N2 | 0.0283 (10) | 0.0250 (10) | 0.0329 (10) | −0.0021 (9) | 0.0002 (9) | −0.0004 (9) |
C1 | 0.0239 (11) | 0.0250 (11) | 0.0225 (10) | 0.0044 (9) | −0.0012 (9) | −0.0009 (9) |
C2 | 0.0228 (10) | 0.0238 (11) | 0.0236 (10) | 0.0009 (9) | 0.0001 (9) | 0.0016 (9) |
C3 | 0.0261 (11) | 0.0259 (12) | 0.0300 (12) | 0.0053 (10) | 0.0036 (9) | 0.0003 (9) |
C4 | 0.0357 (13) | 0.0241 (11) | 0.0326 (12) | 0.0008 (10) | 0.0001 (10) | −0.0010 (9) |
C5 | 0.0315 (13) | 0.0313 (13) | 0.0315 (12) | −0.0059 (10) | 0.0014 (10) | 0.0010 (10) |
C6 | 0.0229 (11) | 0.0359 (12) | 0.0312 (11) | −0.0006 (11) | 0.0032 (11) | −0.0033 (10) |
C7 | 0.0278 (11) | 0.0242 (10) | 0.0235 (10) | 0.0038 (10) | 0.0040 (10) | −0.0040 (8) |
C8 | 0.0327 (12) | 0.0217 (11) | 0.0267 (11) | 0.0030 (10) | 0.0081 (10) | −0.0020 (9) |
C9 | 0.0291 (12) | 0.0290 (12) | 0.0382 (13) | −0.0015 (11) | 0.0069 (12) | −0.0045 (10) |
C10 | 0.0319 (13) | 0.0361 (13) | 0.0340 (13) | 0.0076 (11) | −0.0008 (11) | −0.0102 (10) |
C11 | 0.0465 (14) | 0.0342 (12) | 0.0232 (11) | 0.0075 (13) | 0.0014 (11) | 0.0010 (10) |
C12 | 0.0367 (12) | 0.0247 (11) | 0.0259 (11) | 0.0018 (11) | 0.0062 (11) | −0.0010 (9) |
C13 | 0.0536 (16) | 0.0285 (12) | 0.0331 (13) | −0.0021 (12) | 0.0098 (13) | 0.0058 (11) |
C14 | 0.0455 (18) | 0.0629 (19) | 0.0512 (17) | 0.0037 (16) | −0.0124 (16) | −0.0140 (15) |
C15 | 0.0569 (18) | 0.0351 (14) | 0.0401 (14) | −0.0079 (13) | 0.0094 (13) | 0.0066 (12) |
S1—O1 | 1.4330 (19) | C6—H6A | 0.9900 |
S1—O2 | 1.4379 (18) | C6—H6B | 0.9900 |
S1—N1 | 1.609 (2) | C7—C8 | 1.414 (3) |
S1—C7 | 1.779 (2) | C7—C12 | 1.411 (3) |
N1—C1 | 1.470 (3) | C8—C9 | 1.377 (3) |
N1—H1 | 0.79 (3) | C8—C13 | 1.514 (3) |
N2—C2 | 1.469 (3) | C9—H9 | 0.9500 |
N2—H2A | 0.89 (3) | C9—C10 | 1.384 (3) |
N2—H2B | 0.93 (3) | C10—C11 | 1.384 (4) |
C1—H1A | 1.0000 | C10—C14 | 1.507 (4) |
C1—C2 | 1.535 (3) | C11—H11 | 0.9500 |
C1—C6 | 1.527 (3) | C11—C12 | 1.390 (4) |
C2—H2 | 1.0000 | C12—C15 | 1.509 (3) |
C2—C3 | 1.521 (3) | C13—H13A | 0.9800 |
C3—H3A | 0.9900 | C13—H13B | 0.9800 |
C3—H3B | 0.9900 | C13—H13C | 0.9800 |
C3—C4 | 1.522 (3) | C14—H14A | 0.9800 |
C4—H4A | 0.9900 | C14—H14B | 0.9800 |
C4—H4B | 0.9900 | C14—H14C | 0.9800 |
C4—C5 | 1.525 (3) | C15—H15A | 0.9800 |
C5—H5A | 0.9900 | C15—H15B | 0.9800 |
C5—H5B | 0.9900 | C15—H15C | 0.9800 |
C5—C6 | 1.523 (3) | ||
O1—S1—O2 | 117.62 (12) | C1—C6—H6A | 109.4 |
O1—S1—N1 | 110.46 (11) | C1—C6—H6B | 109.4 |
O1—S1—C7 | 108.68 (11) | C5—C6—C1 | 111.33 (19) |
O2—S1—N1 | 106.31 (11) | C5—C6—H6A | 109.4 |
O2—S1—C7 | 108.86 (11) | C5—C6—H6B | 109.4 |
N1—S1—C7 | 104.06 (11) | H6A—C6—H6B | 108.0 |
S1—N1—H1 | 116 (2) | C8—C7—S1 | 117.96 (16) |
C1—N1—S1 | 122.24 (17) | C12—C7—S1 | 121.78 (19) |
C1—N1—H1 | 120 (2) | C12—C7—C8 | 120.2 (2) |
C2—N2—H2A | 108 (2) | C7—C8—C13 | 124.7 (2) |
C2—N2—H2B | 108.1 (18) | C9—C8—C7 | 118.8 (2) |
H2A—N2—H2B | 107 (3) | C9—C8—C13 | 116.5 (2) |
N1—C1—H1A | 108.4 | C8—C9—H9 | 118.8 |
N1—C1—C2 | 106.87 (18) | C8—C9—C10 | 122.4 (2) |
N1—C1—C6 | 113.39 (19) | C10—C9—H9 | 118.8 |
C2—C1—H1A | 108.4 | C9—C10—C14 | 120.6 (3) |
C6—C1—H1A | 108.4 | C11—C10—C9 | 117.9 (2) |
C6—C1—C2 | 111.36 (17) | C11—C10—C14 | 121.5 (2) |
N2—C2—C1 | 113.59 (18) | C10—C11—H11 | 118.5 |
N2—C2—H2 | 107.1 | C10—C11—C12 | 123.0 (2) |
N2—C2—C3 | 109.98 (18) | C12—C11—H11 | 118.5 |
C1—C2—H2 | 107.1 | C7—C12—C15 | 125.9 (2) |
C3—C2—C1 | 111.70 (18) | C11—C12—C7 | 117.7 (2) |
C3—C2—H2 | 107.1 | C11—C12—C15 | 116.5 (2) |
C2—C3—H3A | 109.1 | C8—C13—H13A | 109.5 |
C2—C3—H3B | 109.1 | C8—C13—H13B | 109.5 |
C2—C3—C4 | 112.32 (19) | C8—C13—H13C | 109.5 |
H3A—C3—H3B | 107.9 | H13A—C13—H13B | 109.5 |
C4—C3—H3A | 109.1 | H13A—C13—H13C | 109.5 |
C4—C3—H3B | 109.1 | H13B—C13—H13C | 109.5 |
C3—C4—H4A | 109.4 | C10—C14—H14A | 109.5 |
C3—C4—H4B | 109.4 | C10—C14—H14B | 109.5 |
C3—C4—C5 | 111.02 (19) | C10—C14—H14C | 109.5 |
H4A—C4—H4B | 108.0 | H14A—C14—H14B | 109.5 |
C5—C4—H4A | 109.4 | H14A—C14—H14C | 109.5 |
C5—C4—H4B | 109.4 | H14B—C14—H14C | 109.5 |
C4—C5—H5A | 109.5 | C12—C15—H15A | 109.5 |
C4—C5—H5B | 109.5 | C12—C15—H15B | 109.5 |
H5A—C5—H5B | 108.1 | C12—C15—H15C | 109.5 |
C6—C5—C4 | 110.51 (19) | H15A—C15—H15B | 109.5 |
C6—C5—H5A | 109.5 | H15A—C15—H15C | 109.5 |
C6—C5—H5B | 109.5 | H15B—C15—H15C | 109.5 |
S1—N1—C1—C2 | −156.04 (17) | C2—C1—C6—C5 | 55.2 (2) |
S1—N1—C1—C6 | 80.9 (2) | C2—C3—C4—C5 | −55.0 (3) |
S1—C7—C8—C9 | 177.22 (17) | C3—C4—C5—C6 | 56.8 (3) |
S1—C7—C8—C13 | −0.7 (3) | C4—C5—C6—C1 | −57.3 (3) |
S1—C7—C12—C11 | −175.90 (18) | C6—C1—C2—N2 | −177.74 (19) |
S1—C7—C12—C15 | 4.4 (3) | C6—C1—C2—C3 | −52.6 (2) |
O1—S1—N1—C1 | −46.1 (2) | C7—S1—N1—C1 | 70.4 (2) |
O1—S1—C7—C8 | −173.93 (17) | C7—C8—C9—C10 | −1.4 (3) |
O1—S1—C7—C12 | 4.7 (2) | C8—C7—C12—C11 | 2.7 (3) |
O2—S1—N1—C1 | −174.73 (18) | C8—C7—C12—C15 | −177.0 (2) |
O2—S1—C7—C8 | −44.7 (2) | C8—C9—C10—C11 | 2.8 (4) |
O2—S1—C7—C12 | 133.97 (19) | C8—C9—C10—C14 | −176.1 (2) |
N1—S1—C7—C8 | 68.36 (19) | C9—C10—C11—C12 | −1.4 (4) |
N1—S1—C7—C12 | −112.99 (19) | C10—C11—C12—C7 | −1.3 (4) |
N1—C1—C2—N2 | 57.9 (2) | C10—C11—C12—C15 | 178.4 (2) |
N1—C1—C2—C3 | −176.97 (18) | C12—C7—C8—C9 | −1.5 (3) |
N1—C1—C6—C5 | 175.8 (2) | C12—C7—C8—C13 | −179.4 (2) |
N2—C2—C3—C4 | 179.90 (18) | C13—C8—C9—C10 | 176.7 (2) |
C1—C2—C3—C4 | 52.8 (3) | C14—C10—C11—C12 | 177.4 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2A···N1 | 0.89 (3) | 2.43 (3) | 2.877 (3) | 111 (2) |
N1—H1···N2i | 0.79 (3) | 2.14 (3) | 2.921 (3) | 170 (3) |
Symmetry code: (i) x−1/2, −y+3/2, −z+1. |
Acknowledgements
The authors thank GVSU for financial support (Weldon Fund, CSCE), the NSF for a 300 MHz Jeol FT–NMR (CCLI-0087655) and Pfizer, Inc. for the donation of a Varian Inova 400 FT–NMR. The CCD-based X-ray diffractometers at Michigan State University were upgraded and/or replaced by departmental funds.
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