2-Hydroxyphenyl 2-methylpyrazolo[1,5-a]pyrimidin-6-yl ketone

The mol­ecules of the title compound, C₁₄H₁₁N₃O₂, form a three-dimensional soft hydrogen-bonded network involving C—H...N hydrogen bonds.

S1. Comment

The investigation of the structure of the title compound, (IV), continues our research into the reactions of 3-aminopyrazoles as intermediates in the preparation of fused pyrazole systems with the potential for diverse medical and biological applications. Reactions between such compounds and α- and β-unsaturated carbonyl derivatives were carried out by Earl et al. (1975) and Shaw & Hildick (1971). Pyrazolo[1,5-a]pyrimidines are very interesting due to their biological activities, which include antileukaemia, antitumour (Quiroga et al., 1998, 1999), antipyretic (Auzzi et al., 1979, and references therein) and antiparasitic properties (Senga et al., 1975). The title compound, (IV), results from the reaction of 3-amino-5-methylpyrazole, (I), with 4-oxo-4H-chromene-3-carbaldehyde, (II), in which condensation takes place between the amino group in the pyrazole ring and the aldehyde in the chromene, in conjunction with nucleophilic displacement of oxygen in the chromene ring by the attack of N2 in the pyrazole ring on C2 in the chromene (see scheme). \sch

Compound (IV) can be divided into two isolated moieties: the pyrazolopyrimidine ring and the 2-hydroxyphenylcarbonyl residue. The bond lengths associated with the pyrazolo[1,5-a]pyrimidine ring confirm the configuration depicted in the scheme. The N8—C3a bond [1.400 (2) Å] is a typical single bond between two trigonal atoms (typical N_trigonal—C_trigonal 1.40 Å; ref?), because there is no delocalization associated with these atoms. This ring and its substituents are planar within experimental error.

The other moiety of the structure, the 2-hydroxyphenylcarbonyl attached to C6 of the pyrazolopyrimidine ring, is also planar, with a strong intramolecular hydrogen bond in which the hydroxyl atom O16 acts as a donor to the carbonyl O9, giving an S(6) primary motif. The phenolic ring is not constrained by this bond to lie in the same plane as the keto group and its connected atoms, as shown by the O9—C9—C11—C16 torsion angle of 17.2 (3)°. This intramolecular bond between the carbonyl and the hydroxy groups confirms the existence of the quinone-hydroxy tautomeric form. The angle between the mean planes of the two rings is 42.53°. Selected bond lengths are given in Table 1.

Each pair of molecules of (IV) related by (−1 − x, −y, 1 − z) is linked to form a dimer by means of C—H···N bonds; atom C3 acts as a donor to atom N4 at (−1 − x, −y, 1 − z), with a D···A distance of 3.528 (2) Å. The action of the centre of symmetry at (−1/2, 0, 1/2) repeats this bond, forming an R₂²(8) ring (Fig. 2). In addition, atom C15 acts as a donor to atom N1 at (3/2 − x, −1/2 + y, 3/2 − z), with a D···A distance of 3.337 (3) Å. This forms a spiral chain around the screw-axis at (3/4, y, 3/4), which in turn forms a C(7) infinite chain along [010]. Query rephrasing. Both these sets of interactions combine to form a complex three-dimensional continuum of further chains. Full details of the hydrogen bonding are given in Table 2.

Examination of the structure with PLATON (Spek, 2000) showed that there were no solvent-accessible voids in the crystal lattice.

S2. Experimental

A solution of 3-amino-5-methylpyrazole (2.0 mmol) and 4-oxo-4H-chromene-3-carbaldehyde (2.0 mmol) in ethanol (10 ml) was heated to reflux for 45 min. Cooling the solution to room temperature afforded bright yellow crystals of (IV) which were filtered out, washed with fresh ethanol and dried. Crystals suitable for X-ray diffraction were obtained after recrystallization from dimethylformamide (yield 80%, m.p. 442–445 K). Analysis calculated for C₁₄H₁₁N₃O₂: C 66.40, H 4.38, N 16.59%; found: C 66.32, H 4.25, N 16.45%.

S3. Refinement

H atoms were treated as riding, with C—H 0.95–0.98 Å and O—H 0.9483 Å. The position of the hydroxyl H atom was based on its position as found on a difference map.

Computing details

Data collection: Kappa-CCD Server Software (Nonius, 1997); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2000); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. A molecular view of (IV) with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. A view of the crystal structure of (IV) showing the dimer formed by the R2^2(8) ring [symmetry code: (i) −1 − x, −y, 1 − z].

2-Hydroxyphenyl 2-methylpyrazolo[1,5-a]pyrimidin-6-yl ketone

Crystal data

C14H11N3O2	F(000) = 528
Mr = 253.26	Dx = 1.439 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 5.6004 (2) Å	Cell parameters from 2591 reflections
b = 11.8172 (5) Å	θ = 3.6–27.5°
c = 17.865 (7) Å	µ = 0.10 mm^−1
β = 98.71 (16)°	T = 150 K
V = 1168.67 (8) Å^3	Plate, yellow
Z = 4	0.20 × 0.15 × 0.08 mm

Data collection

Nonius KAPPA CCD diffractometer	2591 independent reflections
Radiation source: fine-focus sealed X-ray tube	1681 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
ϕ and ω scans with κ offsets	θmax = 27.5°, θmin = 3.6°
Absorption correction: multi-scan (SORTAV; Blessing, 1995, 1997)	h = −7→7
Tmin = 0.980, Tmax = 0.993	k = −11→15
8919 measured reflections	l = −22→22

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 = 1.01	w = 1/[σ^2(Fo^2) + (0.0749P)^2 + 0.0357P] where P = (Fo^2 + 2Fc^2)/3
2591 reflections	(Δ/σ)max = 0.012
173 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.29 e Å^−3

Special details

Geometry. Mean-plane data from the final SHELXL97 refinement run:-

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

- 2.6310 (0.0045) x + 5.3853 (0.0100) y + 14.6225 (0.0096) z = 9.0365 (0.0046)

* −0.0023 (0.0010) N1 * 0.0019 (0.0011) C2 * −0.0008 (0.0011) C3 * −0.0007 (0.0011) C3A * 0.0018 (0.0010) N8

Rms deviation of fitted atoms = 0.0016

− 2.6315 (0.0034) x + 5.3491 (0.0078) y + 14.6541 (0.0077) z = 9.0541 (0.0050)

Angle to previous plane (with approximate e.s.d.) = 0.20 (0.12)

* −0.0009 (0.0012) C3A * 0.0046 (0.0012) N4 * −0.0076 (0.0012) C5 * 0.0068 (0.0012) C6 * −0.0034 (0.0012) C7 * 0.0006 (0.0011) N8

Rms deviation of fitted atoms = 0.0048

− 2.6308 (0.0029) x + 5.3675 (0.0046) y + 14.6387 (0.0047) z = 9.0433 (0.0028)

Angle to previous plane (with approximate e.s.d.) = 0.10 (0.09)

* −0.0030 (0.0013) N1 * 0.0002 (0.0014) C2 * −0.0010 (0.0014) C3 * 0.0014 (0.0016) C3A * 0.0046 (0.0013) N4 * −0.0092 (0.0014) C5 * 0.0058 (0.0014) C6 * −0.0021 (0.0014) C7 * 0.0035 (0.0014) N8

Rms deviation of fitted atoms = 0.0043

− 3.0933 (0.0036) x − 3.1395 (0.0092) y + 15.4479 (0.0068) z = 10.7578 (0.0078)

Angle to previous plane (with approximate e.s.d.) = 42.53 (0.05)

* −0.0236 (0.0012) C11 * 0.0078 (0.0013) C12 * 0.0112 (0.0014) C13 * −0.0144 (0.0014) C14 * −0.0021 (0.0013) C15 * 0.0211 (0.0012) C16

Rms deviation of fitted atoms = 0.0153

− 3.9344 (0.0097) x − 0.0882 (0.0269) y + 14.4677 (0.0252) z = 9.1623 (0.0269)

Angle to previous plane (with approximate e.s.d.) = 17.77 (1/5)

* 0.0000 (0.0000) O9 * 0.0000 (0.0000) C9 * 0.0000 (0.0000) C11 − 0.3677 (0.0055) C16 − 0.6697 (0.0075) O16

Rms deviation of fitted atoms = 0.0000

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

	x	y	z	Uiso*/Ueq
N1	0.1100 (3)	0.17904 (14)	0.57168 (9)	0.0311 (4)
C2	−0.1011 (3)	0.19732 (17)	0.52727 (10)	0.0305 (5)
C21	−0.1395 (4)	0.3051 (2)	0.48346 (12)	0.0425 (6)
C3	−0.2660 (3)	0.10919 (18)	0.52987 (11)	0.0325 (5)
C3a	−0.1491 (3)	0.03148 (17)	0.57953 (10)	0.0273 (4)
N4	−0.2130 (3)	−0.07073 (14)	0.60574 (9)	0.0306 (4)
C5	−0.0481 (3)	−0.12267 (18)	0.65346 (10)	0.0292 (5)
C6	0.1862 (3)	−0.07906 (16)	0.68062 (10)	0.0268 (4)
C7	0.2486 (3)	0.02342 (17)	0.65371 (10)	0.0270 (4)
N8	0.0800 (3)	0.07713 (13)	0.60410 (8)	0.0267 (4)
C9	0.3563 (3)	−0.15406 (17)	0.72926 (10)	0.0284 (5)
O9	0.3277 (3)	−0.25768 (12)	0.72083 (8)	0.0386 (4)
C11	0.5575 (3)	−0.10958 (16)	0.78422 (10)	0.0256 (4)
C12	0.5663 (3)	0.00237 (17)	0.81077 (11)	0.0307 (5)
C13	0.7652 (4)	0.04235 (18)	0.85895 (11)	0.0331 (5)
C14	0.9587 (3)	−0.03014 (18)	0.88131 (11)	0.0348 (5)
C15	0.9530 (3)	−0.14124 (18)	0.85838 (11)	0.0325 (5)
C16	0.7520 (3)	−0.18242 (17)	0.81126 (10)	0.0265 (4)
O16	0.7557 (2)	−0.29223 (11)	0.79074 (7)	0.0331 (4)
H21A	−0.2643	0.3500	0.5026	0.064*
H21B	−0.1913	0.2878	0.4298	0.064*
H21C	0.0118	0.3481	0.4892	0.064*
H3	−0.4254	0.1041	0.5029	0.039*
H5	−0.0879	−0.1949	0.6713	0.035*
H7	0.4038	0.0555	0.6692	0.032*
H12	0.4336	0.0515	0.7954	0.037*
H13	0.7696	0.1183	0.8765	0.040*
H14	1.0977	−0.0022	0.9131	0.042*
H15	1.0861	−0.1897	0.8747	0.039*
H16	0.6027	−0.3122	0.7636	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0330 (9)	0.0262 (10)	0.0329 (9)	0.0001 (7)	0.0006 (7)	0.0034 (7)
C2	0.0337 (11)	0.0309 (12)	0.0261 (10)	0.0048 (9)	0.0017 (8)	−0.0014 (8)
C21	0.0513 (13)	0.0384 (14)	0.0365 (12)	0.0067 (10)	0.0026 (10)	0.0074 (10)
C3	0.0273 (10)	0.0360 (13)	0.0317 (10)	0.0021 (9)	−0.0035 (8)	−0.0034 (9)
C3a	0.0235 (9)	0.0297 (11)	0.0279 (10)	−0.0005 (8)	0.0014 (8)	−0.0052 (8)
N4	0.0275 (9)	0.0329 (10)	0.0304 (9)	−0.0037 (7)	0.0012 (7)	−0.0018 (7)
C5	0.0312 (10)	0.0276 (11)	0.0284 (10)	−0.0025 (8)	0.0033 (8)	−0.0007 (8)
C6	0.0253 (10)	0.0271 (11)	0.0275 (10)	−0.0001 (8)	0.0024 (8)	−0.0023 (8)
C7	0.0223 (9)	0.0290 (11)	0.0279 (10)	0.0031 (8)	−0.0016 (7)	−0.0030 (8)
N8	0.0251 (8)	0.0243 (9)	0.0295 (8)	−0.0007 (6)	0.0009 (6)	−0.0008 (7)
C9	0.0292 (10)	0.0247 (11)	0.0314 (10)	0.0000 (8)	0.0047 (8)	−0.0001 (8)
O9	0.0423 (9)	0.0246 (9)	0.0460 (9)	−0.0004 (6)	−0.0029 (7)	−0.0005 (6)
C11	0.0281 (10)	0.0230 (11)	0.0258 (9)	0.0004 (8)	0.0039 (7)	0.0005 (8)
C12	0.0305 (10)	0.0267 (11)	0.0337 (10)	0.0048 (8)	0.0010 (8)	0.0031 (9)
C13	0.0399 (11)	0.0245 (12)	0.0332 (11)	0.0017 (9)	0.0000 (9)	−0.0011 (8)
C14	0.0327 (11)	0.0336 (13)	0.0351 (11)	−0.0032 (9)	−0.0045 (9)	−0.0002 (9)
C15	0.0304 (10)	0.0327 (12)	0.0326 (10)	0.0062 (9)	−0.0012 (8)	0.0005 (9)
C16	0.0317 (10)	0.0230 (11)	0.0254 (9)	0.0036 (8)	0.0064 (8)	0.0031 (8)
O16	0.0390 (8)	0.0237 (8)	0.0351 (8)	0.0051 (6)	0.0001 (6)	−0.0018 (6)

Geometric parameters (Å, º)

N1—C2	1.338 (2)	C7—N8	1.352 (2)
N1—N8	1.358 (2)	C7—H7	0.9500
C2—C3	1.397 (3)	C9—O9	1.241 (2)
C2—C21	1.493 (3)	C9—C11	1.474 (3)
C21—H21A	0.9800	C11—C12	1.404 (3)
C21—H21B	0.9800	C11—C16	1.415 (3)
C21—H21C	0.9800	C12—C13	1.384 (3)
C3—C3a	1.372 (3)	C12—H12	0.9500
C3—H3	0.9500	C13—C14	1.392 (3)
C3a—N4	1.363 (2)	C13—H13	0.9500
C3a—N8	1.400 (2)	C14—C15	1.374 (3)
N4—C5	1.310 (2)	C14—H14	0.9500
C5—C6	1.425 (3)	C15—C16	1.388 (3)
C5—H5	0.9500	C15—H15	0.9500
C6—C7	1.368 (3)	C16—O16	1.349 (2)
C6—C9	1.482 (3)	O16—H16	0.9483
C2—N1—N8	103.94 (15)	C7—N8—N1	125.23 (16)
N1—C2—C3	112.89 (18)	C7—N8—C3a	122.75 (17)
N1—C2—C21	119.54 (18)	N1—N8—C3a	112.02 (15)
C3—C2—C21	127.55 (18)	O9—C9—C11	120.27 (17)
C2—C21—H21A	109.5	O9—C9—C6	117.32 (17)
C2—C21—H21B	109.5	C11—C9—C6	122.38 (18)
H21A—C21—H21B	109.5	C12—C11—C16	118.18 (17)
C2—C21—H21C	109.5	C12—C11—C9	123.04 (17)
H21A—C21—H21C	109.5	C16—C11—C9	118.79 (18)
H21B—C21—H21C	109.5	C13—C12—C11	121.05 (18)
C3a—C3—C2	105.50 (17)	C13—C12—H12	119.5
C3a—C3—H3	127.2	C11—C12—H12	119.5
C2—C3—H3	127.2	C12—C13—C14	119.14 (19)
N4—C3a—C3	133.71 (18)	C12—C13—H13	120.4
N4—C3a—N8	120.65 (16)	C14—C13—H13	120.4
C3—C3a—N8	105.64 (18)	C15—C14—C13	121.36 (18)
C5—N4—C3a	116.29 (16)	C15—C14—H14	119.3
N4—C5—C6	125.0 (2)	C13—C14—H14	119.3
N4—C5—H5	117.5	C14—C15—C16	119.74 (18)
C6—C5—H5	117.5	C14—C15—H15	120.1
C7—C6—C5	118.14 (17)	C16—C15—H15	120.1
C7—C6—C9	124.04 (16)	O16—C16—C15	117.22 (16)
C5—C6—C9	117.41 (18)	O16—C16—C11	122.36 (16)
N8—C7—C6	117.13 (17)	C15—C16—C11	120.38 (18)
N8—C7—H7	121.4	C16—O16—H16	109.2
C6—C7—H7	121.4
N8—N1—C2—C3	−0.4 (2)	C3—C3a—N8—N1	−0.3 (2)
N8—N1—C2—C21	178.08 (16)	C7—C6—C9—O9	−145.85 (19)
N1—C2—C3—C3a	0.3 (2)	C5—C6—C9—O9	26.7 (2)
C21—C2—C3—C3a	−178.08 (18)	C7—C6—C9—C11	32.3 (3)
C2—C3—C3a—N4	179.8 (2)	C5—C6—C9—C11	−155.16 (17)
C2—C3—C3a—N8	0.0 (2)	O9—C9—C11—C12	−163.23 (18)
C3—C3a—N4—C5	179.25 (19)	C6—C9—C11—C12	18.6 (3)
N8—C3a—N4—C5	−0.9 (2)	O9—C9—C11—C16	17.2 (3)
C3a—N4—C5—C6	1.6 (3)	C6—C9—C11—C16	−160.87 (17)
N4—C5—C6—C7	−1.9 (3)	C16—C11—C12—C13	3.3 (3)
N4—C5—C6—C9	−174.82 (17)	C9—C11—C12—C13	−176.18 (17)
C5—C6—C7—N8	1.3 (3)	C11—C12—C13—C14	−0.1 (3)
C9—C6—C7—N8	173.76 (16)	C12—C13—C14—C15	−2.0 (3)
C6—C7—N8—N1	−179.99 (16)	C13—C14—C15—C16	0.7 (3)
C6—C7—N8—C3a	−0.7 (3)	C14—C15—C16—O16	−179.77 (17)
C2—N1—N8—C7	179.72 (16)	C14—C15—C16—C11	2.6 (3)
C2—N1—N8—C3a	0.41 (19)	C12—C11—C16—O16	177.91 (16)
N4—C3a—N8—C7	0.5 (3)	C9—C11—C16—O16	−2.5 (3)
C3—C3a—N8—C7	−179.59 (16)	C12—C11—C16—C15	−4.6 (3)
N4—C3a—N8—N1	179.88 (16)	C9—C11—C16—C15	174.95 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O16—H16···O9	0.95	1.74	2.562 (2)	144
C3—H3···N4^i	0.95	2.61	3.528 (2)	162
C15—H15···N1^ii	0.95	2.39	3.337 (3)	172

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