cis-7-Aza­bi­cyclo­[4.2.0]­octan-8-one

Under the strain of the quasi-planar β-lactam moiety, the rigid cyclo­hexane ring in the title compound, C₇H₁₁NO, can assume either a flexible boat form (77%) or a flexible half-chair form (23%). These two forms can be present simultaneously. The racemic crystals, isostructural with the cis-6-aza­bi­cyclo­[3.2.0]­heptan-7-one homologue [Reck et al. (1990). Acta Cryst. C46, 720–722], are characterized by N—H...O=C hydrogen bonds that are formed along the screw axes of the similar monoclinic unit cell.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• R factor = 0.052
• wR factor = 0.185
• Data-to-parameter ratio = 13.3

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT301_ALERT_3_B Main Residue  Disorder .........................      31.00 Perc.

Author Response: see _refine_special_details

Alert level C
PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors ....        C3B
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........         16

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1992); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and RPluto in CSD (Allen, 2002); software used to prepare material for publication: SHELXL97.

cis-7-azabicyclo[4.2.0]octan-8-one

Crystal data

C7H11NO	F(000) = 272
Mr = 125.17	Dx = 1.200 Mg m^−3
Monoclinic, P21/c	Melting point = 329–330 K
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.54180 Å
a = 11.333 (1) Å	Cell parameters from 25 reflections
b = 6.474 (1) Å	θ = 29.3–32.3°
c = 10.181 (1) Å	µ = 0.64 mm^−1
β = 112.00 (1)°	T = 293 K
V = 692.59 (14) Å^3	Prism, colourless
Z = 4	0.50 × 0.35 × 0.30 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	1256 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.010
Graphite monochromator	θmax = 75.6°, θmin = 4.2°
ω–θ scans	h = −14→7
Absorption correction: ψ scan (North et al., 1968)	k = −1→8
Tmin = 0.766, Tmax = 0.822	l = −12→12
1554 measured reflections	3 standard reflections every 60 min
1433 independent reflections	intensity decay: 8%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.052	Riding
wR(F^2) = 0.185	w = 1/[σ^2(Fo^2) + (0.101P)^2 + 0.05P] where P = (Fo^2 + 2Fc^2)/3
S = 1.30	(Δ/σ)max < 0.001
1433 reflections	Δρmax = 0.23 e Å^−3
108 parameters	Δρmin = −0.15 e Å^−3
188 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.012 (3)

Special details

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. # start RESPONSE (PLAT301) "Normal" structure refinement (Npar = 82) finished at R1 = 0.083, wR2 = 0.354, S = 3.2. Introducing 2–2 atomic positions for C3, C4, C5 and C6 we got the final model (Npar = 108) of the disordered molecule. # end RESPONSE PLAT301)

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.29462 (14)	0.4259 (2)	0.41635 (14)	0.0589 (4)
H1A	0.3219	0.5110	0.3532	0.077*	0.769 (7)
H1B	0.3234	0.5103	0.3542	0.077*	0.231 (7)
C2A	0.1508 (3)	0.4204 (8)	0.3717 (6)	0.0667 (10)	0.769 (7)
H2A1	0.1201	0.5590	0.3764	0.087*	0.769 (7)
H2A2	0.1128	0.3738	0.2743	0.087*	0.769 (7)
C3A	0.1094 (3)	0.2785 (4)	0.4650 (4)	0.0745 (7)	0.769 (7)
H3A1	0.0175	0.2661	0.4250	0.097*	0.769 (7)
H3A2	0.1331	0.3406	0.5580	0.097*	0.769 (7)
C4A	0.1676 (3)	0.0642 (5)	0.4810 (4)	0.0745 (7)	0.769 (7)
H4A1	0.0988	−0.0342	0.4407	0.097*	0.769 (7)
H4A2	0.2072	0.0342	0.5814	0.097*	0.769 (7)
C5A	0.2654 (4)	0.0250 (7)	0.4148 (6)	0.0622 (8)	0.769 (7)
H5A1	0.3134	−0.0988	0.4555	0.081*	0.769 (7)
H5A2	0.2224	0.0032	0.3138	0.081*	0.769 (7)
C2B	0.1574 (9)	0.470 (2)	0.394 (3)	0.072 (4)	0.231 (7)
H2B1	0.1540	0.5391	0.4774	0.094*	0.231 (7)
H2B2	0.1207	0.5616	0.3139	0.094*	0.231 (7)
C3B	0.0810 (9)	0.2735 (17)	0.3687 (19)	0.103 (3)	0.231 (7)
H3B1	0.0691	0.2220	0.2751	0.134*	0.231 (7)
H3B2	−0.0025	0.3051	0.3693	0.134*	0.231 (7)
C4B	0.1404 (11)	0.104 (3)	0.476 (2)	0.103 (3)	0.231 (7)
H4B1	0.0841	−0.0137	0.4612	0.134*	0.231 (7)
H4B2	0.1641	0.1539	0.5723	0.134*	0.231 (7)
C5B	0.2567 (16)	0.053 (2)	0.442 (2)	0.084 (5)	0.231 (7)
H5B1	0.3020	−0.0546	0.5073	0.109*	0.231 (7)
H5B2	0.2246	−0.0097	0.3482	0.109*	0.231 (7)
C6	0.35598 (15)	0.2074 (3)	0.44054 (16)	0.0610 (5)
H6A	0.4135	0.1907	0.3895	0.079*	0.769 (7)
H6B	0.4071	0.1713	0.3847	0.079*	0.231 (7)
N7	0.42568 (13)	0.2716 (2)	0.58807 (14)	0.0661 (4)
H7	0.4799	0.2087	0.6598	0.086*
C8	0.37583 (14)	0.4609 (2)	0.57222 (15)	0.0589 (4)
O1	0.38991 (13)	0.60397 (19)	0.65522 (12)	0.0788 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0662 (9)	0.0549 (8)	0.0517 (8)	−0.0100 (6)	0.0175 (6)	0.0072 (6)
C2A	0.0619 (16)	0.059 (2)	0.0662 (19)	0.0025 (11)	0.0095 (12)	−0.0031 (18)
C3A	0.0711 (12)	0.0739 (13)	0.0868 (14)	−0.0113 (8)	0.0392 (11)	−0.0019 (9)
C4A	0.0711 (12)	0.0739 (13)	0.0868 (14)	−0.0113 (8)	0.0392 (11)	−0.0019 (9)
C5A	0.0791 (16)	0.0479 (17)	0.065 (2)	−0.0039 (12)	0.0328 (12)	−0.0103 (14)
C2B	0.067 (5)	0.049 (6)	0.082 (9)	−0.009 (4)	0.007 (4)	−0.009 (5)
C3B	0.064 (4)	0.094 (6)	0.149 (8)	−0.009 (3)	0.038 (4)	0.019 (5)
C4B	0.064 (4)	0.094 (6)	0.149 (8)	−0.009 (3)	0.038 (4)	0.019 (5)
C5B	0.140 (11)	0.044 (5)	0.074 (8)	0.008 (5)	0.047 (6)	−0.022 (4)
C6	0.0633 (9)	0.0638 (9)	0.0589 (8)	−0.0011 (6)	0.0263 (7)	−0.0006 (6)
N7	0.0622 (8)	0.0669 (8)	0.0588 (8)	0.0041 (6)	0.0107 (6)	0.0050 (6)
C8	0.0591 (8)	0.0573 (8)	0.0544 (8)	−0.0117 (6)	0.0144 (6)	0.0031 (6)
O1	0.0929 (9)	0.0622 (8)	0.0672 (7)	−0.0139 (6)	0.0137 (6)	−0.0088 (5)

Geometric parameters (Å, º)

C1—C2B	1.513 (8)	C2B—C3B	1.506 (8)
C1—C2A	1.519 (4)	C2B—H2B1	0.9700
C1—C8	1.524 (2)	C2B—H2B2	0.9700
C1—C6	1.555 (2)	C3B—C4B	1.514 (8)
C1—H1A	0.9800	C3B—H3B1	0.9700
C1—H1B	0.9800	C3B—H3B2	0.9700
C2A—C3A	1.516 (5)	C4B—C5B	1.521 (8)
C2A—H2A1	0.9700	C4B—H4B1	0.9700
C2A—H2A2	0.9700	C4B—H4B2	0.9700
C3A—C4A	1.519 (4)	C5B—C6	1.507 (12)
C3A—H3A1	0.9700	C5B—H5B1	0.9700
C3A—H3A2	0.9700	C5B—H5B2	0.9700
C4A—C5A	1.519 (4)	C6—N7	1.4710 (19)
C4A—H4A1	0.9700	C6—H6A	0.9800
C4A—H4A2	0.9700	C6—H6B	0.9800
C5A—C6	1.521 (4)	N7—C8	1.334 (2)
C5A—H5A1	0.9700	N7—H7	0.8600
C5A—H5A2	0.9700	C8—O1	1.2232 (19)
C2B—C1—C8	108.2 (9)	C3B—C2B—H2B2	109.4
C2A—C1—C8	118.5 (2)	C1—C2B—H2B2	109.4
C2B—C1—C6	124.7 (5)	H2B1—C2B—H2B2	108.0
C2A—C1—C6	113.1 (2)	C2B—C3B—C4B	114.5 (15)
C8—C1—C6	84.87 (11)	C2B—C3B—H3B1	108.6
C2A—C1—H1A	112.5	C4B—C3B—H3B1	108.6
C8—C1—H1A	112.5	C2B—C3B—H3B2	108.6
C6—C1—H1A	112.5	C4B—C3B—H3B2	108.6
C2B—C1—H1B	111.8	H3B1—C3B—H3B2	107.6
C8—C1—H1B	111.8	C3B—C4B—C5B	100.5 (14)
C6—C1—H1B	111.8	C3B—C4B—H4B1	111.7
C3A—C2A—C1	112.1 (3)	C5B—C4B—H4B1	111.7
C3A—C2A—H2A1	109.2	C3B—C4B—H4B2	111.7
C1—C2A—H2A1	109.2	C5B—C4B—H4B2	111.7
C3A—C2A—H2A2	109.2	H4B1—C4B—H4B2	109.4
C1—C2A—H2A2	109.2	C6—C5B—C4B	124.8 (11)
H2A1—C2A—H2A2	107.9	C6—C5B—H5B1	106.1
C2A—C3A—C4A	113.4 (3)	C4B—C5B—H5B1	106.1
C2A—C3A—H3A1	108.9	C6—C5B—H5B2	106.1
C4A—C3A—H3A1	108.9	C4B—C5B—H5B2	106.1
C2A—C3A—H3A2	108.9	H5B1—C5B—H5B2	106.3
C4A—C3A—H3A2	108.9	N7—C6—C5B	107.3 (8)
H3A1—C3A—H3A2	107.7	N7—C6—C5A	117.7 (2)
C3A—C4A—C5A	117.7 (3)	N7—C6—C1	86.67 (11)
C3A—C4A—H4A1	107.9	C5B—C6—C1	108.2 (7)
C5A—C4A—H4A1	107.9	C5A—C6—C1	116.5 (2)
C3A—C4A—H4A2	107.9	N7—C6—H6A	111.3
C5A—C4A—H4A2	107.9	C5A—C6—H6A	111.3
H4A1—C4A—H4A2	107.2	C1—C6—H6A	111.3
C6—C5A—C4A	110.6 (3)	N7—C6—H6B	116.8
C6—C5A—H5A1	109.5	C5B—C6—H6B	116.8
C4A—C5A—H5A1	109.5	C1—C6—H6B	116.8
C6—C5A—H5A2	109.5	C8—N7—C6	95.45 (12)
C4A—C5A—H5A2	109.5	C8—N7—H7	132.3
H5A1—C5A—H5A2	108.1	C6—N7—H7	132.3
C3B—C2B—C1	111.0 (8)	O1—C8—N7	132.26 (14)
C3B—C2B—H2B1	109.4	O1—C8—C1	134.71 (15)
C1—C2B—H2B1	109.4	N7—C8—C1	93.01 (12)
C8—C1—C2A—C3A	−49.1 (4)	C8—C1—C6—N7	0.16 (10)
C6—C1—C2A—C3A	47.8 (4)	C2B—C1—C6—C5B	−1.3 (14)
C1—C2A—C3A—C4A	−51.1 (5)	C8—C1—C6—C5B	107.3 (9)
C2A—C3A—C4A—C5A	5.1 (5)	C2A—C1—C6—C5A	0.8 (3)
C3A—C4A—C5A—C6	41.9 (5)	C8—C1—C6—C5A	119.6 (2)
C8—C1—C2B—C3B	−108.3 (16)	C5B—C6—N7—C8	−108.3 (7)
C6—C1—C2B—C3B	−12 (2)	C5A—C6—N7—C8	−118.5 (2)
C1—C2B—C3B—C4B	50 (2)	C1—C6—N7—C8	−0.18 (12)
C2B—C3B—C4B—C5B	−67 (2)	C6—N7—C8—O1	178.67 (17)
C3B—C4B—C5B—C6	56 (2)	C6—N7—C8—C1	0.19 (12)
C4B—C5B—C6—N7	69 (2)	C2B—C1—C8—O1	−53.7 (7)
C4B—C5B—C6—C1	−24 (2)	C2A—C1—C8—O1	−65.1 (3)
C4A—C5A—C6—N7	56.2 (5)	C6—C1—C8—O1	−178.60 (18)
C4A—C5A—C6—C1	−44.6 (5)	C2B—C1—C8—N7	124.7 (6)
C2B—C1—C6—N7	−108.4 (11)	C2A—C1—C8—N7	113.3 (3)
C2A—C1—C6—N7	−118.6 (3)	C6—C1—C8—N7	−0.18 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N7—H7···O1^i	0.86	2.03	2.8781 (17)	171

Symmetry code: (i) −x+1, y−1/2, −z+3/2.