N-[(1S,2S)-2-Amino-1,2-diphenyl­eth­yl]-4-methyl­benzene­sulfonamide [(S,S)-TsDPEN]

Claudine Schlemmer; Dieter Schollmeyer; Nancy Blank; Alexander Stoye; Till Opatz

doi:10.1107/S1600536810049159

. 2010 Nov 27;66(Pt 12):o3343. doi: 10.1107/S1600536810049159

N-[(1S,2S)-2-Amino-1,2-diphenylethyl]-4-methylbenzenesulfonamide [(S,S)-TsDPEN]

Claudine Schlemmer ^a, Dieter Schollmeyer ^a, Nancy Blank ^a, Alexander Stoye ^a, Till Opatz ^a,^*

PMCID: PMC3011471 PMID: 21589615

Abstract

The crystal structure of the title compound, C₂₁H₂₂N₂O₂S, shows a network of N—H⋯N and N—H⋯O hydrogen bonds. The tolyl and 1-phenyl rings are almost mutually coplanar [7.89 (9)°], while the 2-phenyl ring makes a dihedral angle of 50.8 (1) ° with the 1-phenyl ring. An intramolecular N—H⋯N hydrogen bond stabilizes the molecular conformation.

Related literature

For the synthesis of the title compound, see: Vanino (1923 ▶); Mistryukov (2002 ▶). The title compound was synthesized as a ligand for Ru-catalyzed asymmetric transfer hydrogenations. Similar to BINAP introduced by the same author, the synthesized diamine permits highly enantioselective asymmetric hydrogenation reactions, see: Noyori (1996 ▶).

Experimental

Crystal data

C₂₁H₂₂N₂O₂S
M _r = 366.47
Orthorhombic,
a = 6.3892 (6) Å
b = 12.2290 (11) Å
c = 24.281 (2) Å
V = 1897.2 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.19 mm⁻¹
T = 173 K
0.50 × 0.05 × 0.05 mm

Data collection

Bruker APEXII CCD diffractometer
37668 measured reflections
4511 independent reflections
3865 reflections with I > 2σ(I)
R _int = 0.062

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.086
S = 1.02
4511 reflections
236 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.30 e Å⁻³
Absolute structure: Flack (1983 ▶), 1905 Friedel pairs
Flack parameter: 0.01 (7)

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810049159/bt5420sup1.cif

e-66-o3343-sup1.cif^{(20.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810049159/bt5420Isup2.hkl

e-66-o3343-Isup2.hkl^{(221KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N11—H11⋯N20ⁱ	0.97	2.09	3.041 (2)	167
N20—H20A⋯N11	0.99	2.31	2.8149 (19)	110
N20—H20B⋯O10ⁱ	0.87	2.17	3.0236 (19)	166

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

The title compound is formed from hydrobenzamide in a base catalyzed one-pot reaction involving deprotonation to a diazapentadienide anion, cyclization to amarine, and isomerization at elevated temperature under formation of isoamarine. Subsequent reduction with Al/Hg then furnishes racemic stilbenediamine. To obtain optically pure (S,S)—N-p-toluenesulfonyl-1,2-diphenylethylenediamine, the racemate is converted to the diastereomeric L-tartrate salts which are separated by crystallization. After conversion to the free base, the (S,S)-1,2-diphenylethylenediamine is reacted with p-toluenesulfonyl chloride to give the desired product as colorless crystals. The crystal structure is characterized by a network consisting of the three following hydrogen bonds: N11—H11···N20 (2.09 Å), N20—H20B···O10 (2.17 Å) and N20—H20A···N11 (2.31 Å). The first two bonds build the network to a second molecule while the last one stabilizes the molecular conformation. Furthermore, the aromatic rings C1—C6 and C13—C18 are almost coplanar while the ring C21–26 exhibits a dihedral angle of 50.8 (1) ° to the ring C13—C18. The carbon atoms C12 and C19 are (S)-configurated.

Experimental

The title compound was prepared from hydrobenzamide (Vanino, 1923) as follows: To a suspension of hydrobenzamide (66 g, 0.22 mol) in dry DMSO (100 ml) was added solid NaOH (1.2 g, 0.03 mol) under argon atmosphere and vigorous stirring. After 5 min, the mixture was heated to 323 K and held at this temperature for 1 h. Then, the reaction mixture was heated to 403 K and stirred at that temperature for another 3 h. The mixture was cooled down to 353 K and diluted with ethanol and ammonia (28% in water). For completion of the crystallization, the mixture was allowed to stand at room temperature for 20 h. The crystalline isoamarine was filtered off and washed with 2-propanol (Mistryukov, 2002). Yield: 57.2 g (87%, Lit.:90%), m.p.: 474 K (Lit.: 471–473 K). In an argon atmosphere a mixture of isoamarine (50 g, 0.17 mol), pieces of aluminium foil (13.5 g, 0.5 mol), and HgCl₂ (3 g, 0.011 mol) were suspended in dry THF (300 ml). The suspension was stirred for 15 min. Then, water (9 ml) in THF (25 ml) was added during 1.5 h. After 2 h, another portion of water (25 ml) was added and the mixture was allowed to stand for 20 h. A concentrated solution of aqueous ammonia (50 ml) was added and the mixture was set aside for another 24 h before it was filtered. The filtrate was concentrated and the distillate was used to wash the residue on the filter. The obtained filtrate was also concentrated and combined with the remainder obtained in the first evaporation. The resulting oil was dissolved in a mixture of methanol (150 ml), concentrated HCl (75 ml) and water (50 ml). The crystaline dihydrochloride was filtered off, washed with dioxane and dried. To obtain the free base, the salt was dissolved in water (100 ml), NaOH was added and the solution was extracted four times with CHCl₃. The combined organic layers were concentrated to dryness (see Mistryukov (2002)). Yield: 19.0 g (53%, Lit.: 78%), m.p.: 354 K (Lit.: 355 K). The obtained diamine (14.5 g, 0.068 mol) was dissolved in ethanol (77 ml) and warmed to 343 K. To this solution, L-(+)-tartaric acid (10.2 g, 0.068 mol) dissolved in hot (343 K) ethanol (77 ml) was added. The mixture was allowed to cool to ambient temperature before filtration. The crystals were washed with ethanol and dried in vacuo. The salt was then dissolved in boiling water (77 ml), ethanol (77 ml) was added and the mixture was allowed to cool slowly to room temperature. This procedure was repeated twice to give the desired (S,S)-diamine-(R,R)-tartrate salt. Yield: 6.0 g (48%, Lit.: 63–69%), m.p.: 465 K, [α]_D²³: -10.4° (H₂O, c=1.0), Lit.: -10.8° (H₂O, c=1.3). The salt was suspended in water (80 ml), cooled to 273 K and 8 ml of 50% aqueous solution of NaOH were added dropwise. The solution was extracted with CH₂Cl₂, the combined organic layers were washed with brine and dried over anhydrous Na₂SO₄. The solvent was evaporated in vacuo. From the combined filtrates and mother liquors, the (R,R)-diamine can be obtained in a similar fashion by crystallization with D-(–)-tartaric acid. Yield: 3.2 g (44%, Lit.: 57–66%), m.p.: 356 K, Lit.: 356 K, [α]_D²³: -101.9° (MeOH, c=1.0), Lit.: -106.0° (MeOH, c=1.1). For the tosylation, (S,S)-1,2-diphenylethylenediamine (0.3 g, 1.41 mmol) was dissolved in dry CH₂Cl₂ (3 ml) and Et₃N (320 µL) was added. Then, p-toluenesulfonyl chloride (0.256 g, 1.41 mmol) dissolved in dry CH₂Cl₂ (9 mL) was added dropwise. After 30 min of stirring, the solution was diluted with CH₂Cl₂ to twice its volume and washed with saturated NaHCO₃, brine and dried over anhydrous Na₂SO₄. After evaporation of the solvent, the product was purified by flash chromatography on silica (petroleum ether/ethyl acetate, 2:3) and subsequently recrystallized from benzene. Yield: 0.33 g (62%, Lit.: 49%), m.p.: 403 K, [α]_D²³: -90° (MeOH, c=1.0), Lit.: -89° (MeOH, c=1.0).