tert-Butyl N-{2-[bis­(prop-2-yn-1-yl)amino]­phen­yl}carbamate

Manavendra K Singh; Alka Agarwal; Charu Mahawar; Satish K Awasthi

doi:10.1107/S1600536811016862

. 2011 May 11;67(Pt 6):o1382. doi: 10.1107/S1600536811016862

tert-Butyl N-{2-[bis(prop-2-yn-1-yl)amino]phenyl}carbamate

Manavendra K Singh ^a, Alka Agarwal ^a,^*, Charu Mahawar ^a, Satish K Awasthi ^b,^*

PMCID: PMC3120597 PMID: 21754772

Abstract

In the crystal of the title compound, C₁₇H₂₀N₂O₂, the molecules are linked by C—H⋯O interactions. Intramolecular C—H⋯O and N—H⋯N hydrogen bonds also occur.

Related literature

For applications of alkyne scaffolds in biology, medicinal and materials chemistry, see: Diederich et al. (2005 ▶); Stang & Diederich (1995 ▶); Lam et al. (1988 ▶); Patai (1994 ▶). For background to click chemistry, which involves 1,3-dipolar cycloaddition of an alkyne with an azide and is an efficient and highly versatile tool that has allowed the preparation of a variety of macromolecule conjugates such as sugars, peptides or proteins and DNA, see: Rostovtsev et al. (2002 ▶). For the synthesis, see: Lilienkampf et al. (2009 ▶). For intermolecular interactions, see: Steiner & Desiraju (1998 ▶). For intramolecular C—H⋯O hydrogen bonds, see: Smith et al. (1993 ▶). graphic file with name e-67-o1382-scheme1.jpg

Experimental

Crystal data

C₁₇H₂₀N₂O₂
M _r = 284.35
Monoclinic,
a = 19.1936 (12) Å
b = 8.7181 (4) Å
c = 19.7619 (9) Å
β = 99.513 (5)°
V = 3261.3 (3) Å³
Z = 8
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 K
0.40 × 0.39 × 0.38 mm

Data collection

Oxford Diffraction Xcalibur Eos diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T _min = 0.953, T _max = 1.000
6969 measured reflections
4389 independent reflections
2427 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.156
S = 0.96
4389 reflections
194 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811016862/zj2008sup1.cif

e-67-o1382-sup1.cif^{(18.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811016862/zj2008Isup2.hkl

e-67-o1382-Isup2.hkl^{(177.2KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811016862/zj2008Isup3.cml

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
C10—H10B⋯O1ⁱ	0.97	2.55	3.512 (2)	171
C9—H9⋯O1ⁱⁱ	0.93	2.28	3.194 (3)	166
C2—H2⋯O1	0.93	2.32	2.911 (3)	121
N1—HN1⋯N2	0.810 (19)	2.28 (2)	2.703 (2)	114 (2)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

AA, MKS and CM are thankful to the University Grant Commission (scheme No. 34–311/2008), New Delhi, and Banaras Hindu University, Varanasi, India, for financial assistance. SKA is thankful to the University of Delhi, India, for financial assistance.

supplementary crystallographic information

Comment

The carbon-carbon triple bond is an important and versatile functional group in organic chemistry. Alkynes are found in numerous natural products as well as in synthetic organic molecules. These alkyne scaffolds have various applications in biology, medicinal and material chemistry (Diederich et al., 2005; Stang & Diederich 1995; Lam et al., 1988; Patai 1994). Click chemistry developed by Sharpless (Rostovtsev et al., 2002) involves 1,3-dipolar cycloaddition of alkyne with azide as an efficient and highly versatile tool that has allowed to prepare a variety of macromolecule conjugates such as sugars, peptides or proteins and DNA. As part of our ongoing work on antimicrobial studies on small molecules, we characterized and report here the crystal structure of [2-(di-prop-2-ynyl-amino)phenyl]carbamic acid tert-butyl ester (Figure1).

In the crystal structure, the compound is stabilized by intermolecular interaction between C10—H10B···O1 and C9—H9···O1 (Steiner & Desiraju, 1998) and intramolecular hydrogen bond between C2—H2···O1 (Smith et al., 1993) and N1—HN1···N2 as seen in the crystal packing diagram along b axis (Table 1, Figure 2). Considering C1—C6 C13—C15 N1 N2 O1 O2 atom as plane A, C7 C8 C9 atom as plane B, C10 C11 C12 atom as plane C, the dihedral angels between planes A/B, A/C and B/C are 74.74°, 57.52°, 48.94° respectively, suggests that the molecule is not co-planar.

Experimental

The synthesis of the title compound was carried out according to the published procedure (Lilienkampf, et al., 2009). Briefly, to a solution of (2-aminophenyl)carbamic acid tert-butyl ester (1.5 g, 7.2 mmol) in dry acetone was added anhydrous K₂CO₃ (7.95 g, 54.6 m mol) and reaction mixture was refluxed for 15–30 minutes. Subsequently, KI (0.60 g m, 3.6 mmol) and propargyl bromide (0.75 ml, 7.8 mmol) were added and further refluxed the reaction mixture for 18 hrs. The reaction mixture was cooled, filtered, and the filtrate was evaporated in vacuo to give the product. The crude product was purified by column chromatography using hexane and dichloromethane (65:35) as eluent. The purified product was recrystallized from hexane-dichloromethane (1:1). The colourless crystals were obtained by slow evaporation of solvent at room temperature in several days. Yield: 20%.

¹H NMR (CDCl₃): 8.11 (bs, 1H, NH), 7.56–7.55 (m, 1H, Ar—H), 7.35- 7.32 (m, 1H, Ar—H), 7.19–7.14 (m, 1H, Ar—H), 6.99–6.94 (m, 1H, Ar—H), 3.83 (s, 4H, CH₂), 2.28 (s, 2H, CH), 1.51 (s, 9H, 3xCH₃).