2-(4-Bromo­phen­yl)oxazolo[3,2-a]pyrimidinium perchlorate

The title compound, C₁₂H₈BrN₂O⁺·ClO₄⁻, was synthesized and characterized by ¹H NMR and single-crystal X-ray diffraction. The essentially planar p-bromo­phenyl fragment and plane of the heterocyclic system form a dihedral angle of 1.79 (7)°. Short inter­molecular contacts (ca 3.0 Å) involving O atoms of a perchlorate anion may indicate the positive charge concentration on the bridgehead N atom of the cation.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.041
• wR factor = 0.111
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    C10    -   C15     ..       7.54 su

Alert level C
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors for        Cl1
PLAT432_ALERT_2_C Short Inter X...Y Contact  O12    ..  C9      ..       3.00 Ang.
PLAT432_ALERT_2_C Short Inter X...Y Contact  O13    ..  C5      ..       2.97 Ang.
PLAT432_ALERT_2_C Short Inter X...Y Contact  O14    ..  C9      ..       2.99 Ang.

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: CAD-4 EXPRESS; cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wokadlo, (1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999).

2-(4-bromophenyl)oxazolo[3,2-a]pyrimidinium perchlorate

Crystal data

C12H8BrN2O^+·ClO4^−	F(000) = 744
Mr = 375.56	Dx = 1.879 Mg m^−3
Monoclinic, P21/n	Melting point: 553 K
Hall symbol: -P 2yn	Cu Kα radiation, λ = 1.5418 Å
a = 6.291 (2) Å	Cell parameters from 25 reflections
b = 12.052 (2) Å	θ = 34–36°
c = 17.688 (4) Å	µ = 6.33 mm^−1
β = 98.19 (2)°	T = 293 K
V = 1327.4 (6) Å^3	Prism, colourless
Z = 4	0.15 × 0.15 × 0.15 mm

Data collection

Enraf–Nonius CAD 4 diffractometer	Rint = 0.084
Radiation source: Fine-focus sealed tube	θmax = 74.9°, θmin = 4.5°
Graphite monochromator	h = −7→7
ω scans	k = 0→15
2811 measured reflections	l = 0→22
2714 independent reflections	1 standard reflections every 60 min
2375 reflections with I > 2σ(I)	intensity decay: 3%

Refinement

Refinement on F^2	Primary atom site location: Direct
Least-squares matrix: Full	Secondary atom site location: Difmap
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: Geom
wR(F^2) = 0.111	H-atom parameters constrained
S = 0.92	w = 1/[σ^2(Fo^2) + (0.0909P)^2 + 0.38P] where P = (Fo^2 + 2Fc^2)/3
2714 reflections	(Δ/σ)max = 0.001
190 parameters	Δρmax = 0.48 e Å^−3
0 restraints	Δρmin = −0.47 e Å^−3

Special details

Experimental. 1-[2-(4-Bromophenyl)-2-oxoethyl] pyrimidin-2(1H)-one (1) was prepared analogously to previously described procedure (Rybakov et al., 2006). Hydrochloride of pyrimidone-2 (1) (26.5 g, 0.2 mol) was suspended in 500 ml of dry acetone. Solution of 0.1 mol of p-bromophenacylbromide in 100 ml acetone and 0.4 mol K₂CO₃ was added with stirring. Reaction mixture was stirred for 2 days at room temperature, and then the solvent was evaporated in vacuum. The residue was washed with water and then with ethylacetate. The white solid product was isolated by suction and recrystallized from acetonitrile. Yield 95%, m.p. 510–512 K. IR (Nujol): 1700, 1660 cm^{-1. 1}H NMR (360 MHz, DMSO-d₆): δ J(Hz) 5.43 (s, 2H, CH₂), 6.41 (m, 1H, H-5), 7.72 (m, 2H, H—Ar, BB'), 7.99 (m, 2H, H—Ar, AA'), 8.08 (m, 1H, H-4), 8.57 (m, 1H, H-6). Calculated, %: C 49.17 H 3.09 N 9.56. C₁₂H₉BrN₂O₂. Found, %: C 48.75 H 2.89 N 9.36. 2-(p-bromophenyl)oxazolo[3,2-a]pyrimidinium perchlorate (2). ¹H NMR (360 MHz, DMSO-d₆): δ J(Hz) 7.81 (m, 2H, H—Ar, BB'), 8.02 (m, 2H, H—Ar, AA'), 8.14 (dd, J₆₇ = 4.6 Hz, J₆₅ = 6.3 Hz, 1H, H-6), 9.31 (s, 1H, H-3), 9.36 (dd, J₇₆ = 4.6 Hz, J₇₅ = 1.8 Hz, 1H, H-7), 9.68 (dd, J₅₆ = 6.3 Hz, J₅₇ = 1.8 Hz, 1H, H-5). Calculated, %: C 38.38 H 2.15 N 7.46. C₁₂H₈BrClN₂O₅. Found, %: C 38.24 H 1.86 N 7.71.

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

	x	y	z	Uiso*/Ueq
Br13	0.04764 (4)	0.07749 (3)	−0.111497 (17)	0.04885 (15)
N1	1.1667 (3)	0.32306 (15)	0.13154 (10)	0.0294 (4)
C2	0.9824 (4)	0.25917 (19)	0.12708 (13)	0.0337 (5)
H2	0.9388	0.2163	0.1658	0.040*
C3	0.8792 (4)	0.27135 (17)	0.05578 (12)	0.0282 (4)
O4	0.9946 (3)	0.34262 (14)	0.01574 (8)	0.0322 (3)
C5	1.1668 (4)	0.37276 (18)	0.06303 (12)	0.0286 (4)
N6	1.3173 (4)	0.43928 (18)	0.04443 (12)	0.0372 (5)
C7	1.4759 (4)	0.4589 (2)	0.10101 (15)	0.0394 (6)
H7	1.5863	0.5057	0.0913	0.047*
C8	1.4867 (4)	0.4136 (2)	0.17387 (15)	0.0382 (6)
H8	1.6016	0.4300	0.2113	0.046*
C9	1.3271 (4)	0.34487 (19)	0.18955 (13)	0.0338 (5)
H9	1.3278	0.3142	0.2378	0.041*
C10	0.6796 (4)	0.22816 (18)	0.01586 (12)	0.0306 (5)
C11	0.6130 (4)	0.2531 (2)	−0.06063 (13)	0.0345 (5)
H11	0.6964	0.2993	−0.0866	0.041*
C12	0.4233 (4)	0.2094 (2)	−0.09832 (13)	0.0364 (5)
H12	0.3775	0.2268	−0.1493	0.044*
C13	0.3052 (4)	0.1409 (2)	−0.05974 (13)	0.0344 (5)
C14	0.3618 (4)	0.1158 (2)	0.01629 (13)	0.0349 (5)
H14	0.2741	0.0714	0.0418	0.042*
C15	0.5530 (4)	0.1584 (2)	0.05422 (12)	0.0323 (5)
H15	0.5969	0.1405	0.1052	0.039*
Cl1	0.01661 (10)	0.57078 (5)	0.23198 (3)	0.03760 (17)
O11	−0.1441 (5)	0.6452 (3)	0.25201 (16)	0.0786 (8)
O12	0.0014 (5)	0.4655 (3)	0.26678 (18)	0.0850 (9)
O13	−0.0160 (5)	0.5490 (3)	0.15224 (18)	0.0840 (8)
O14	0.2249 (5)	0.6165 (3)	0.24949 (19)	0.0863 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br13	0.0423 (2)	0.0571 (2)	0.0461 (2)	−0.00886 (12)	0.00254 (13)	−0.00393 (12)
N1	0.0384 (10)	0.0227 (9)	0.0285 (8)	0.0020 (7)	0.0101 (7)	0.0025 (7)
C2	0.0408 (12)	0.0252 (11)	0.0362 (11)	−0.0007 (9)	0.0098 (9)	0.0048 (9)
C3	0.0344 (11)	0.0197 (9)	0.0328 (10)	0.0035 (8)	0.0130 (8)	−0.0012 (8)
O4	0.0388 (8)	0.0317 (8)	0.0269 (7)	0.0010 (7)	0.0077 (6)	0.0040 (6)
C5	0.0360 (11)	0.0249 (10)	0.0264 (9)	0.0076 (9)	0.0092 (8)	0.0013 (8)
N6	0.0403 (11)	0.0355 (11)	0.0387 (10)	−0.0017 (9)	0.0151 (9)	0.0089 (8)
C7	0.0454 (14)	0.0286 (12)	0.0486 (14)	−0.0067 (10)	0.0220 (11)	−0.0067 (10)
C8	0.0395 (13)	0.0337 (12)	0.0404 (13)	0.0007 (10)	0.0023 (10)	−0.0050 (9)
C9	0.0436 (12)	0.0272 (11)	0.0297 (10)	−0.0016 (10)	0.0018 (9)	−0.0031 (8)
C10	0.0388 (11)	0.0224 (10)	0.0313 (10)	0.0059 (9)	0.0075 (8)	−0.0076 (8)
C11	0.0422 (12)	0.0334 (11)	0.0304 (10)	0.0021 (10)	0.0144 (9)	0.0013 (9)
C12	0.0396 (12)	0.0407 (13)	0.0281 (10)	0.0044 (10)	0.0018 (9)	0.0027 (9)
C13	0.0367 (12)	0.0359 (12)	0.0311 (10)	0.0065 (10)	0.0065 (9)	−0.0091 (9)
C14	0.0376 (12)	0.0346 (12)	0.0351 (11)	−0.0014 (10)	0.0140 (9)	−0.0021 (9)
C15	0.0375 (12)	0.0313 (11)	0.0291 (10)	−0.0024 (9)	0.0077 (8)	0.0021 (8)
Cl1	0.0424 (3)	0.0317 (3)	0.0392 (3)	0.0033 (2)	0.0077 (2)	−0.0078 (2)
O11	0.0806 (18)	0.0799 (19)	0.0769 (16)	0.0289 (15)	0.0169 (14)	−0.0084 (14)
O12	0.097 (2)	0.0731 (18)	0.0895 (19)	0.0289 (16)	0.0290 (16)	0.0060 (15)
O13	0.090 (2)	0.086 (2)	0.0774 (18)	0.0256 (17)	0.0172 (15)	−0.0076 (16)
O14	0.083 (2)	0.0756 (19)	0.101 (2)	0.0190 (16)	0.0133 (17)	−0.0188 (16)

Geometric parameters (Å, º)

Br13—C13	1.904 (3)	C9—H9	0.9300
N1—C5	1.352 (3)	C10—C11	1.391 (3)
N1—C9	1.359 (3)	C10—C15	1.398 (3)
N1—C2	1.384 (3)	C11—C12	1.385 (4)
C2—C3	1.342 (3)	C11—H11	0.9300
C2—H2	0.9300	C12—C13	1.358 (4)
C3—O4	1.383 (3)	C12—H12	0.9300
C3—C10	1.447 (3)	C13—C14	1.375 (3)
O4—C5	1.322 (3)	C14—C15	1.390 (3)
C5—N6	1.317 (3)	C14—H14	0.9300
N6—C7	1.330 (3)	C15—H15	0.9300
C7—C8	1.392 (4)	Cl1—O14	1.415 (4)
C7—H7	0.9300	Cl1—O12	1.419 (3)
C8—C9	1.360 (4)	Cl1—O13	1.420 (3)
C8—H8	0.9300	Cl1—O11	1.433 (3)
C5—N1—C9	119.7 (2)	C11—C10—C3	121.1 (2)
C5—N1—C2	107.63 (19)	C15—C10—C3	119.6 (2)
C9—N1—C2	132.6 (2)	C12—C11—C10	120.4 (2)
C3—C2—N1	106.4 (2)	C12—C11—H11	119.8
C3—C2—H2	126.8	C10—C11—H11	119.8
N1—C2—H2	126.8	C13—C12—C11	119.0 (2)
C2—C3—O4	109.3 (2)	C13—C12—H12	120.5
C2—C3—C10	133.6 (2)	C11—C12—H12	120.5
O4—C3—C10	117.12 (19)	C12—C13—C14	122.8 (2)
C5—O4—C3	106.82 (17)	C12—C13—Br13	119.43 (18)
N6—C5—O4	124.2 (2)	C14—C13—Br13	117.80 (19)
N6—C5—N1	125.9 (2)	C13—C14—C15	118.5 (2)
O4—C5—N1	109.9 (2)	C13—C14—H14	120.8
C5—N6—C7	114.1 (2)	C15—C14—H14	120.8
N6—C7—C8	124.0 (2)	C14—C15—C10	120.1 (2)
N6—C7—H7	118.0	C14—C15—H15	120.0
C8—C7—H7	118.0	C10—C15—H15	120.0
C9—C8—C7	119.2 (2)	O14—Cl1—O12	111.7 (2)
C9—C8—H8	120.4	O14—Cl1—O13	106.7 (2)
C7—C8—H8	120.4	O12—Cl1—O13	104.86 (19)
N1—C9—C8	117.0 (2)	O14—Cl1—O11	111.53 (17)
N1—C9—H9	121.5	O12—Cl1—O11	111.00 (18)
C8—C9—H9	121.5	O13—Cl1—O11	110.72 (17)
C11—C10—C15	119.2 (2)