Crystal structure of ethyl (2S)-9-meth­oxy-2-methyl-4-oxo-3,4,5,6-tetra­hydro-2H- 2,6-methano­benzo[g][1,3,5]oxa­diazocine-11-carboxyl­ate

A Dhandapani; S Manivarman; S Subashchandrabose; B Gunasekaran

doi:10.1107/S2056989015000559

. 2015 Jan 17;71(Pt 2):o117–o118. doi: 10.1107/S2056989015000559

Crystal structure of ethyl (2S)-9-methoxy-2-methyl-4-oxo-3,4,5,6-tetrahydro-2H- 2,6-methanobenzo[g][1,3,5]oxadiazocine-11-carboxylate

A Dhandapani ^a, S Manivarman ^a, S Subashchandrabose ^b, B Gunasekaran ^c,^*

PMCID: PMC4384574 PMID: 25878860

Abstract

In the title compound, C₁₅H₁₈N₂O₅, the methoxyphenyl ring makes a dihedral angle of 84.70 (12)° with the mean plane of the tetrahydropyrimidin-2(1H)-one ring. Both the pyran and tetrahydropyrimidin-2(1H)-one rings have distorted envelope conformations with the carboxylate-substituted C atom as the flap. In the crystal, molecules are linked via pairs of N—H⋯O hydrogen bonds, forming zigzag chains propagating along [010], which enclose R ² ₂(8) ring motifs. The chains are linked by C—H⋯π interactions, forming a two-dimensional network parallel to (100).

Keywords: crystal structure, hydropyrimidine, oxadiazocine, pyran, hydrogen bonding

Related literature

For the biological activity of dihydropyrimidine derivatives, see: Hurst & Hull (1961 ▸); Ashok et al. (2007 ▸); Bahekar & Shinde (2004 ▸); Mayer et al. (1999 ▸); Kappe (2000 ▸); For the crystal structures of two very similar compounds, see: Jing et al. (2009 ▸); Yar et al. (2014 ▸; Liu et al. (2014 ▸). graphic file with name e-71-0o117-scheme1.jpg

Experimental

Crystal data

C₁₅H₁₈N₂O₅
M _r = 306.31
Monoclinic,
a = 9.6982 (14) Å
b = 7.4802 (12) Å
c = 10.8293 (17) Å
β = 111.252 (5)°
V = 732.2 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 295 K
0.25 × 0.20 × 0.20 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▸) T _min = 0.954, T _max = 0.975
10886 measured reflections
3030 independent reflections
2029 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.071
wR(F ²) = 0.175
S = 1.14
3030 reflections
203 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.25 e Å⁻³
Absolute structure: Flack (1983 ▸), 1371 Friedel pairs
Absolute structure parameter: 0.01 (4)

Data collection: APEX2 (Bruker, 2008 ▸); cell refinement: SAINT (Bruker, 2008 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸, 2015 ▸); molecular graphics: PLATON (Spek, 2009 ▸); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015000559/su5057sup1.cif

e-71-0o117-sup1.cif^{(24.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015000559/su5057Isup2.hkl

e-71-0o117-Isup2.hkl^{(145.6KB, hkl)}

Click here for additional data file.^{(6.2KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015000559/su5057Isup3.cml

Click here for additional data file.^{(1.9MB, tif)}

. DOI: 10.1107/S2056989015000559/su5057fig1.tif

The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

Click here for additional data file.^{(1.2MB, tif)}

b . DOI: 10.1107/S2056989015000559/su5057fig2.tif

The crystal packing of the title compound, viewed along the b axis. Hydrogen bonds are shown as dashed lines (see Table 1 for details).

CCDC reference: 1043105

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

Cg1 is the centroid of the C1C6 ring.

DHA	DH	HA	D A	DHA
N1H1O2ⁱ	0.86	2.12	2.962(5)	168
N2H2AO2ⁱⁱ	0.86	2.11	2.936(4)	162
C14H14B Cg1ⁱⁱⁱ	0.96	2.62	3.570(6)	171

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

supplementary crystallographic information

S1. Comment

Dihydropyrimidine derivatives have recently received great attention because of their wide range of therapeutic and pharmacological properties, such as antiviral (Hurst & Hull, 1961), antitumor, antibacterial and antifungal (Ashok et al., 2007), anti-inflammatory (Bahekar & Shinde, 2004), antihypertensive agents, and neuropeptide Y (NPY) antagonists (Mayer et al., 1999). The natural products containing these heterocyclic moieties have been studied as new leads for AIDS therapies (Kappe, 2000).

The molecular structure of the title compound is illustrated in Fig. 1. The methoxyphenyl ring (C1-C6) makes a dihedral angles of 84.70 (12) ° with the mean plane of the tetrahydropyrimidin-2(1H)-one ring (N1/N2/C7-C10). Both the pyran (O1/C3/C4/C7/C10)and tetrahydropyrimidin-2(1H)-one rings have distorted envelope con formations with atom C10 as the flap.

The geometrical parameters of the title molecule agree well with those reported for two very similar compounds, viz. ethyl 2-methyl-4-oxo-3,4,5,6-tetrahydro-2H-2,6-methanobenzo[g][1,3,5]oxadiazocine-11-carboxylate (Jing et al., 2009; Yar et al., 2014) and methyl 2-methyl-4-oxo-3,4,5,6-tetrahydro-2H-2,6-methanobenzo[g][1,3,5]oxadiazocine-11-carboxylate (Liu et al., 2014)

In the crystal, molecules are linked via pairs of N—H···O hydrogen bonds forming zigzag chains propagating along [010], which enclose R²₂(8) ring motifs (Table 1 and Fig. 2). The chains are linked by C-H···π interactions forming a two-dimensional network parallel to (100).

S2. Experimental

2-hydroxy-4-methoxybenzaldehyde (0.76 g, 5 mmol) and urea (0.9 g, 15 mmol) were added to an ethanolic solution of ethyl acetoacetate (0.65 ml, 5 mmol). To this mixture CeCl₃.7H₂O (0.465 g, 25%) was added slowly with stirring. After the addition was complete the reaction mixture was reflux at 363 K. The reaction mixture was then cooled to room temperature, then poured onto crushed ice water and stirred for 10 min. The solid that separated was filtered under suction, washed with water, and then recrystallized from DMSO giving colourless block-like crystals (yield: 96%; m.p.: 463 K).