N-(2-Naphthyl­oxy­methyl­carbonyl)­pyrrolidine

N-(2-Naphthyl­oxy­methyl­carbonyl)­pyrrolidine, C₁₆H₁₇NO₂, is a potential antiamnesic agent. In the solid state, the pyrrolidine ring adopts an envelope conformation. Except for the atom of the envelope flap, the entire mol­ecule is essentially planar.

Key indicators

• Single-crystal X-ray study
• T = 160 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.052
• wR factor = 0.144
• Data-to-parameter ratio = 21.4

checkCIF/PLATON results

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S1. Comment

The conformation of molecules with anti-amnesic activity has attracted considerable interest (Amato et al., 1991). The pyrrolidine moiety is a requisite for several active compounds currently used in the therapy of pathological brain-aging phenomena (Piracetam, Oxyracetam and Pramiracetam). The ring-extended N-analogues of 2-pyrrolidinone, viz. 2-aryl-3-piperazinone compounds, have been found to possess the characteristic nootropic pharmacological profile (Amato et al., 1991). The present paper reports the structure and conformation of the title compound, (I), which was determined as a continuation of the investigation of a new class of anti-amnesic agents (Thamotharan, Parthasarathi, Gupta et al., 2003a,b,c; Thamotharan, Parthasarathi, Malik et al., 2003a,b).

Fig. 1 shows a view of the molecule of (I), with the atomic numbering scheme. The bond lengths and angles in (I) are comparable with those in the related structures of 1-(2-naphthyloxymethylcarbonyl)piperidine and 3-methyl-1-(2-naphthyloxymethylcarbonyl)piperidine (Thamotharan, Parthasarathi, Malik et al., 2003a), 4-(2-naphthyloxymethylcarbonyl)morpholine and 4-methyl-1-(2-naphthyloxymethylcarbonyl)piperazine (Thamotharan, Parthasarathi, Gupta et al., 2003a), as well as N,N-dimethyl-2-(2-naphthyloxy)acetamide monohydrate (Thamotharan, Parthasarathi, Gupta et al., 2003c). In (I), the central fragment C2—O11—C12—C13—N14 is planar, with a maximum deviation of 0.0223 (13) Å for atom C12. This central unit is virtually coplanar with the plane of the naphthalene moiety, the angle between the planes being 1.48 (5)°. The C2—O11—C12—C13 and O11—C12—C13—N14 torsion angles show that the central unit has an antiperiplanar conformation.

The pyrrolidine ring in nootropics usually has a half-chair (C₂, twist-envelope) conformation, (Thamotharan, Parthasarathi, Malik et al., 2003b and references therein). In (I), however, the pyrrolidine ring adopts an envelope conformation, with atom C17 as the flap, a pseudo-rotation angle Δ = 86.0 (1)° and a maximum torsion angle ϕ_m = 36.5 (1)° (Rao et al., 1981) for the atom sequence N14—C15—C16—C17—C18. Ignoring C17, the mean plane through the remainder of the pyrrolidine ring is almost coplanar with the plane of the naphthalene moiety, the angle between the planes being 3.55 (9)°. Thus, the entire molecule is essentially planar.

The exocyclic bond angle C1—C2—O11 deviates significantly from the normal value of 120° (Table 1) and this may be due to steric repulsion (H1···H121 =2.31 Å, H1···H122 = 2.28 Å). The crystal packing is influenced only by normal van der Waals contacts.

S2. Experimental

Methyl 2-(2-naphthyloxy)acetate (0.5 g) was reacted with pyrrolidine. The oily product obtained was treated with water. The precipitate obtained was filtered, dried and crystallized from acetone to afford (I) (yield, 0.51 g, 86.39%; m.p. 397–399 K).

S3. Refinement

All H atoms were placed in geometrically idealized positions (C—H = 0.95–0.99 Å) and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C). Reflection 1 0 0 was partially obscured by the beam stop and was omitted.

Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Figures

Fig. 1. View of the molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by circles of arbitrary radii.

N-(2-naphthyloxymethylcarbonyl)pyrrolidine

Crystal data

C16H17NO2	F(000) = 544
Mr = 255.31	Dx = 1.343 Mg m^−3
Monoclinic, P21/c	Melting point: 397 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 10.6427 (2) Å	Cell parameters from 3899 reflections
b = 8.8035 (2) Å	θ = 2.0–30.0°
c = 14.4306 (2) Å	µ = 0.09 mm^−1
β = 110.9738 (11)°	T = 160 K
V = 1262.46 (4) Å^3	Prism, colourless
Z = 4	0.23 × 0.20 × 0.17 mm

Data collection

Nonius KappaCCD diffractometer	2775 reflections with I > 2σ(I)
Radiation source: Nonius FR591 sealed tube generator	Rint = 0.047
Horizontally mounted graphite crystal monochromator	θmax = 30.0°, θmin = 2.8°
Detector resolution: 9 pixels mm^-1	h = 0→14
ϕ and ω scans with κ offsets	k = 0→12
33348 measured reflections	l = −20→18
3686 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.144	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0765P)^2 + 0.209P] where P = (Fo^2 + 2Fc^2)/3
3685 reflections	(Δ/σ)max < 0.001
172 parameters	Δρmax = 0.51 e Å^−3
0 restraints	Δρmin = −0.30 e Å^−3

Special details

Experimental. Solvent used: acetone Cooling Device: Oxford Cryosystems Cryostream 700 Crystal mount: glued on a glass fibre Mosaicity (°.): 0.484 (2) Frames collected: 326 Seconds exposure per frame: 40 Degrees rotation per frame: 2.0 Crystal-Detector distance (mm): 28.0

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.

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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O11	0.72111 (8)	0.52679 (10)	0.40282 (6)	0.0258 (2)
O13	0.91728 (9)	0.71575 (11)	0.40863 (6)	0.0329 (2)
N14	1.00984 (10)	0.71437 (12)	0.57646 (7)	0.0250 (2)
C1	0.59653 (11)	0.36322 (13)	0.47607 (8)	0.0225 (3)
H1	0.6561	0.3833	0.5418	0.027*
C2	0.61699 (11)	0.43114 (13)	0.39705 (8)	0.0223 (2)
C3	0.52769 (12)	0.40350 (14)	0.29858 (8)	0.0252 (3)
H3	0.5418	0.4528	0.2446	0.030*
C4	0.42181 (12)	0.30663 (13)	0.28106 (8)	0.0247 (3)
H4	0.3633	0.2884	0.2148	0.030*
C5	0.28892 (12)	0.13087 (14)	0.34436 (9)	0.0255 (3)
H5	0.2297	0.1106	0.2785	0.031*
C6	0.26823 (13)	0.06134 (14)	0.42287 (9)	0.0272 (3)
H6	0.1954	−0.0074	0.4112	0.033*
C7	0.35519 (13)	0.09200 (14)	0.52097 (9)	0.0273 (3)
H7	0.3402	0.0439	0.5750	0.033*
C8	0.46083 (12)	0.19043 (13)	0.53880 (8)	0.0248 (3)
H8	0.5180	0.2105	0.6052	0.030*
C9	0.48618 (11)	0.26294 (13)	0.45948 (8)	0.0214 (2)
C10	0.39775 (11)	0.23241 (13)	0.36073 (8)	0.0218 (2)
C12	0.81293 (12)	0.56020 (14)	0.49915 (8)	0.0236 (3)
H121	0.8574	0.4659	0.5323	0.028*
H122	0.7648	0.6060	0.5396	0.028*
C13	0.91719 (12)	0.67071 (14)	0.48940 (8)	0.0238 (3)
C15	1.01720 (12)	0.66274 (15)	0.67521 (9)	0.0277 (3)
H151	1.0330	0.5518	0.6828	0.033*
H152	0.9335	0.6876	0.6870	0.033*
C16	1.13665 (16)	0.75073 (18)	0.74576 (11)	0.0421 (4)
H161	1.1198	0.7810	0.8064	0.051*
H162	1.2197	0.6887	0.7652	0.051*
C17	1.14902 (18)	0.88943 (19)	0.68716 (11)	0.0456 (4)
H171	1.0868	0.9708	0.6909	0.055*
H172	1.2421	0.9294	0.7120	0.055*
C18	1.11106 (12)	0.83033 (15)	0.58232 (9)	0.0286 (3)
H181	1.0729	0.9121	0.5332	0.034*
H182	1.1898	0.7855	0.5712	0.034*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O11	0.0235 (4)	0.0310 (5)	0.0208 (4)	−0.0041 (3)	0.0054 (3)	0.0001 (3)
O13	0.0333 (5)	0.0406 (5)	0.0250 (4)	−0.0040 (4)	0.0106 (4)	0.0043 (4)
N14	0.0218 (5)	0.0271 (5)	0.0245 (5)	−0.0022 (4)	0.0063 (4)	0.0008 (4)
C1	0.0209 (5)	0.0261 (6)	0.0189 (5)	0.0036 (4)	0.0051 (4)	−0.0006 (4)
C2	0.0209 (5)	0.0235 (6)	0.0226 (6)	0.0017 (4)	0.0081 (4)	−0.0007 (4)
C3	0.0281 (6)	0.0281 (6)	0.0196 (6)	0.0004 (5)	0.0087 (5)	0.0008 (4)
C4	0.0266 (6)	0.0273 (6)	0.0176 (5)	0.0012 (5)	0.0047 (4)	−0.0009 (4)
C5	0.0237 (6)	0.0285 (6)	0.0229 (5)	0.0005 (5)	0.0068 (4)	−0.0042 (4)
C6	0.0271 (6)	0.0279 (6)	0.0287 (6)	−0.0025 (5)	0.0126 (5)	−0.0032 (5)
C7	0.0317 (7)	0.0291 (6)	0.0242 (6)	0.0019 (5)	0.0135 (5)	0.0012 (5)
C8	0.0266 (6)	0.0280 (6)	0.0196 (5)	0.0027 (5)	0.0079 (5)	−0.0001 (4)
C9	0.0214 (5)	0.0230 (6)	0.0202 (5)	0.0050 (4)	0.0080 (4)	0.0002 (4)
C10	0.0227 (5)	0.0234 (6)	0.0196 (5)	0.0037 (4)	0.0078 (4)	−0.0012 (4)
C12	0.0216 (5)	0.0273 (6)	0.0205 (5)	0.0003 (5)	0.0061 (4)	−0.0007 (4)
C13	0.0210 (5)	0.0254 (6)	0.0251 (6)	0.0031 (5)	0.0083 (4)	0.0013 (4)
C15	0.0257 (6)	0.0323 (7)	0.0230 (6)	−0.0008 (5)	0.0061 (5)	0.0021 (5)
C16	0.0444 (8)	0.0446 (9)	0.0286 (7)	−0.0122 (7)	0.0023 (6)	−0.0005 (6)
C17	0.0513 (9)	0.0408 (8)	0.0407 (8)	−0.0156 (7)	0.0117 (7)	−0.0075 (6)
C18	0.0232 (6)	0.0262 (6)	0.0355 (7)	−0.0021 (5)	0.0095 (5)	0.0006 (5)

Geometric parameters (Å, º)

O11—C2	1.3703 (14)	C7—C8	1.3690 (17)
O11—C12	1.4147 (14)	C7—H7	0.9500
O13—C13	1.2315 (15)	C8—C9	1.4182 (16)
N14—C13	1.3459 (15)	C8—H8	0.9500
N14—C18	1.4643 (16)	C9—C10	1.4243 (16)
N14—C15	1.4709 (15)	C12—C13	1.5197 (17)
C1—C2	1.3723 (16)	C12—H121	0.9900
C1—C9	1.4194 (17)	C12—H122	0.9900
C1—H1	0.9500	C15—C16	1.5252 (19)
C2—C3	1.4194 (16)	C15—H151	0.9900
C3—C4	1.3626 (17)	C15—H152	0.9900
C3—H3	0.9500	C16—C17	1.518 (2)
C4—C10	1.4231 (16)	C16—H161	0.9900
C4—H4	0.9500	C16—H162	0.9900
C5—C6	1.3732 (18)	C17—C18	1.512 (2)
C5—C10	1.4144 (17)	C17—H171	0.9900
C5—H5	0.9500	C17—H172	0.9900
C6—C7	1.4126 (17)	C18—H181	0.9900
C6—H6	0.9500	C18—H182	0.9900
C2—O11—C12	116.52 (9)	O11—C12—C13	108.21 (9)
C13—N14—C18	122.07 (10)	O11—C12—H121	110.1
C13—N14—C15	125.67 (10)	C13—C12—H121	110.1
C18—N14—C15	112.12 (9)	O11—C12—H122	110.1
C2—C1—C9	119.91 (10)	C13—C12—H122	110.1
C2—C1—H1	120.0	H121—C12—H122	108.4
C9—C1—H1	120.0	O13—C13—N14	122.89 (11)
O11—C2—C1	125.64 (10)	O13—C13—C12	122.80 (10)
O11—C2—C3	113.79 (10)	N14—C13—C12	114.31 (10)
C1—C2—C3	120.57 (11)	N14—C15—C16	103.44 (10)
C4—C3—C2	120.40 (11)	N14—C15—H151	111.1
C4—C3—H3	119.8	C16—C15—H151	111.1
C2—C3—H3	119.8	N14—C15—H152	111.1
C3—C4—C10	120.89 (10)	C16—C15—H152	111.1
C3—C4—H4	119.6	H151—C15—H152	109.0
C10—C4—H4	119.6	C17—C16—C15	104.74 (11)
C6—C5—C10	120.50 (11)	C17—C16—H161	110.8
C6—C5—H5	119.8	C15—C16—H161	110.8
C10—C5—H5	119.8	C17—C16—H162	110.8
C5—C6—C7	120.04 (11)	C15—C16—H162	110.8
C5—C6—H6	120.0	H161—C16—H162	108.9
C7—C6—H6	120.0	C18—C17—C16	103.61 (12)
C8—C7—C6	120.58 (11)	C18—C17—H171	111.0
C8—C7—H7	119.7	C16—C17—H171	111.0
C6—C7—H7	119.7	C18—C17—H172	111.0
C7—C8—C9	120.92 (10)	C16—C17—H172	111.0
C7—C8—H8	119.5	H171—C17—H172	109.0
C9—C8—H8	119.5	N14—C18—C17	103.02 (11)
C8—C9—C1	121.92 (10)	N14—C18—H181	111.2
C8—C9—C10	118.30 (11)	C17—C18—H181	111.2
C1—C9—C10	119.78 (10)	N14—C18—H182	111.2
C5—C10—C4	121.91 (10)	C17—C18—H182	111.2
C5—C10—C9	119.65 (11)	H181—C18—H182	109.1
C4—C10—C9	118.44 (11)
C12—O11—C2—C1	−1.55 (17)	C8—C9—C10—C5	−0.53 (16)
C12—O11—C2—C3	179.33 (10)	C1—C9—C10—C5	179.16 (10)
C9—C1—C2—O11	−178.29 (10)	C8—C9—C10—C4	179.13 (10)
C9—C1—C2—C3	0.77 (18)	C1—C9—C10—C4	−1.17 (16)
O11—C2—C3—C4	177.85 (10)	C2—O11—C12—C13	−178.34 (9)
C1—C2—C3—C4	−1.31 (18)	C18—N14—C13—O13	5.85 (19)
C2—C3—C4—C10	0.58 (18)	C15—N14—C13—O13	−178.70 (11)
C10—C5—C6—C7	0.57 (18)	C18—N14—C13—C12	−174.56 (10)
C5—C6—C7—C8	−0.23 (19)	C15—N14—C13—C12	0.90 (17)
C6—C7—C8—C9	−0.50 (18)	O11—C12—C13—O13	−1.60 (16)
C7—C8—C9—C1	−178.81 (11)	O11—C12—C13—N14	178.81 (10)
C7—C8—C9—C10	0.88 (17)	C13—N14—C15—C16	−178.27 (12)
C2—C1—C9—C8	−179.84 (11)	C18—N14—C15—C16	−2.43 (14)
C2—C1—C9—C10	0.47 (17)	N14—C15—C16—C17	23.52 (15)
C6—C5—C10—C4	−179.83 (11)	C15—C16—C17—C18	−35.72 (16)
C6—C5—C10—C9	−0.18 (17)	C13—N14—C18—C17	156.45 (12)
C3—C4—C10—C5	−179.69 (11)	C15—N14—C18—C17	−19.56 (14)
C3—C4—C10—C9	0.65 (17)	C16—C17—C18—N14	33.41 (15)