7-Amino-2-tert-butyl-5-methyl­pyrazolo[1,5-a]pyrimidine: a three-dimensional framework structure built from two N—H⋯N hydrogen bonds

Portilla, J.; Quiroga, J.; Cobo, J.; Low, J.N.; Glidewell, C.

doi:10.1107/S0108270106044817

organic compounds

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 63| Part 1| January 2007| Pages o26-o28

doi:10.1107/S0108270106044817

7-Amino-2-tert-butyl-5-methylpyrazolo[1,5-a]pyrimidine: a three-dimensional framework structure built from two N—H⋯N hydrogen bonds

Jaime Portilla,^a Jairo Quiroga,^a Justo Cobo,^b John N. Low ^c and Christopher Glidewell ^d ^*

^aGrupo de Investigación de Compuestos Heterocíclicos, Departamento de Química, Universidad de Valle, AA 25360 Cali, Colombia, ^bDepartamento de Química Inorgánica y Orgánica, Universidad de Jaén, 23071 Jaén, Spain, ^cDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and ^dSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
^*Correspondence e-mail: cg@st-andrews.ac.uk

(Received 26 October 2006; accepted 27 October 2006; online 12 December 2006)

The bond distances in the title compound, C₁₁H₁₆N₄, provide evidence for peripheral delocalization of π electrons. The molecules are linked by two independent N—H⋯N hydrogen bonds into a three-dimensional framework structure.

Comment

We are interested in the synthesis of fused pyrazole systems, in particular pyrazolo[1,5-a]pyrimidine, because of their potential biological activity. We report here the structure of 7-amino-2-tert-butyl-5-methylpyrazolo[1,5-a]pyrimidine, (I) (Fig. 1), and we compare this with the structure of the isomeric compound 7-amino-5-tert-butyl-2-methylpyrazolo[1,5-a]pyrimidine, (II) (Portilla, Quiroga, de la Torre et al., 2006 ) and with that of the simpler analogue 7-amino-2,5-dimethylpyrazolo[1,5-a]pyrimidine, which crystallizes as a hemihydrate, (III) (Portilla, Quiroga, Cobo et al., 2006 ).

The bond distances within the fused heterocyclic system (Table 1) show evidence for electronic delocalization. Thus, within the periphery of the classically localized form (I), the N1=C2 and N4=C5 bonds are both formally double bonds, while C3A—N4 and C7—N7A are both single bonds; however, N1=C2 is not significantly shorter than C3A—N4. Similarly, the C3=C3A and C6=C7 bonds are both formally double bonds, while C2—C3 and C5—C6 are both formally single bonds; however, the C—C distances in the periphery span an overall range of less than 0.02 Å, with no clear distinction between those which are formally single bonds and those which are formally double bonds. These observations, taken all together, point to a significant contribution to the overall molecular–electronic structure from a peripherally delocalized ten-π-electron form.

The molecules of compound (I) are linked by two independent N—H⋯N hydrogen bonds (Table 2) into a three-dimensional framework structure, whose formation is rather easily analysed in terms of two simple substructures, one of which is one-dimensional and the other of which is finite and zero-dimensional.

In the one-dimensional substructure, amino atom N7 in the molecule at (x, y, z) acts as a hydrogen-bond donor, via H7A, to the pyrimidine ring atom N4 in the molecule at (−y + $[{1\over 2}]$ , x − $[{1\over 2}]$ + x, z + $[{1\over 4}]$ ), while atom N7 at (−y + $[{1\over 2}]$ , x − $[{1\over 2}]$ , z + $[{1\over 4}]$ ) in turn acts as a donor to atom N4 at (−x + 1, −y, z + $[{1\over 2}]$ ), so forming a C(6) (Bernstein et al., 1995 ) helical chain running along the [001] direction and generated by the 4₁ screw axis along ( $[1\over2]$ , 0, z) (Fig. 2). The finite substructure serves to link the C(6) chains; atom N7 in the molecule at (x, y, z) acts as a hydrogen-bond donor, via H7B, to the pyrazole ring atom N1 in the molecule at (y, x, −z + 1), so forming an R₂²(10) motif generated by the twofold rotation axis along x = y at z = $[1\over 2]$ (Fig. 3). This motif directly links the C(6) chain along ( $[1\over 2]$ , 0, z) with the four similar chains along (0, $[1\over2]$ , z), (0, − $[1\over2]$ , z), (1, − $[1\over2]$ , z) and (1, $[1\over2]$ , z), and by propagation of this interaction, all of the C(6) chains, and hence all of the molecules, are linked into a single three-dimensional framework structure, built from only two hydrogen bonds.

In the isomeric compound (II), which crystallizes with Z′ = 2 in the space group P $[\overline{1}]$ (Portilla, Quiroga, de la Torre et al., 2006), the supramolecular structure is only one-dimensional, in contrast to the three-dimensional structure of (I); four independent N—H⋯N hydrogen bonds link the molecules of (II) into chains containing three different types of centrosymmetric ring, one of R₂²(10) type and two of R₄⁴(14) type. In the hemihydrate (III), which crystallizes in the space group C2 (Portilla, Quiroga, Cobo et al., 2006), the components are linked by a combination of O—H⋯N, N—H⋯N and N—H⋯O hydrogen bonds into a complex three-dimensional framework. Hence, minor changes in the simple hydrocarbyl substituents in compounds (I)–(III) provoke significant changes both in crystallization behaviour, as manifested in the space groups and Z′ values, and in the supramolecular structures.

Figure 1
A molecule of (I)

, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
A stereoview of part of the crystal structure of (I)

, showing the formation of a hydrogen-bonded C(6) helical chain generated by the 4₁ screw axis along ( $[1\over2]$ , 0, z). For the sake of clarity, H atoms bonded to C atoms have been omitted.

Figure 3
Part of the crystal structure of (I)

, showing the formation of the R₂²(10) motif which links the C(6) helical chains. For the sake of clarity, H atoms bonded to C atoms have been omitted. Atoms marked with an asterisk (*) are at the symmetry position (y, x, −z + 1).

Experimental

An intimate mixture of 5-amino-3-tert-butyl-1H-pyrazole (139 mg, 1 mmol) and 3-aminocrotononitrile (82 mg, 1 mmol) was placed in an open Pyrex-glass vessel and irradiated in a domestic microwave oven for 2.5 min at 600 W. The reaction mixture was then extracted with ethanol and, after removal of the solvent, the product was crystallized from ethanol, providing colourless crystals of (I) suitable for single-crystal X-ray diffraction (yield 92%; m.p. 489–490 K). MS m/z (%): 204 (100, M⁺), 189 (18).

Crystal data

C₁₁H₁₆N₄
M_r = 204.28
Tetragonal, P 4₁ 2₁ 2
a = 10.8271 (2) Å
c = 19.9208 (3) Å
V = 2335.24 (7) Å³
Z = 8
D_x = 1.162 Mg m⁻³
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 120 (2) K
Block, colourless
0.50 × 0.50 × 0.20 mm

Data collection

Bruker–Nonius KappaCCD diffractometer
φ and ω scans
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.941, T_max = 0.985
16594 measured reflections
1605 independent reflections
1418 reflections with I > 2σ(I)
R_int = 0.038
θ_max = 27.5°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.035
wR(F²) = 0.091
S = 1.05
1605 reflections
140 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0594P)² + 0.2575P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Selected bond lengths (Å)

N1—C2	1.3491 (19)
C2—C3	1.401 (2)
C3—C3A	1.384 (2)
C3A—N4	1.353 (2)
N4—C5	1.332 (2)
C5—C6	1.398 (2)
C6—C7	1.389 (2)
C7—N7A	1.3705 (19)
N7A—N1	1.3683 (17)
C3A—N7A	1.3906 (18)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N7—H7A⋯N4ⁱ	0.95	1.97	2.9034 (18)	168
N7—H7B⋯N1ⁱⁱ	0.95	2.27	3.1202 (19)	149
Symmetry codes: (i) $[-y+{\script{1\over 2}}, x-{\script{1\over 2}}, z+{\script{1\over 4}}]$ ; (ii) y, x, -z+1.

The systematic absences permitted P4₁2₁2 and P4₃2₁2 as possible space groups, but in the absence of significant resonant scattering, it was not possible to distinguish between these enantiomeric space groups. P4₁2₁2 was selected, although this choice has no chemical significance, and the Friedel-equivalent reflections were merged. All H atoms were located in difference maps and then treated as riding atoms, with C—H distances of 0.95 (CH) or 0.98 Å (CH₃) and N—H distances of 0.95 Å, and with U_iso(H) values of kU_eq(C,N), where k = 1.5 for the methyl groups and 1.2 otherwise.

Data collection: COLLECT (Hooft, 1999 ); cell refinement: DENZO (Otwinowski & Minor, 1997 ) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003 ) and SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S0108270106044817/sk3071sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270106044817/sk3071Isup2.hkl

Comment top

We are interested in the synthesis of fused pyrazolo systems, in particular pyrazolo[1,5-a]pyrimidine, because of their potential biological activity. We report here the structure of 7-amino-2-tert-butyl-5-methylpyrazolo[1,5-a]pyrimidine, (I) (Fig. 1), and we compare this with the structure of the isomeric compound 7-amino-5-tert-butyl-2-methylpyrazolo[1,5-a]pyrimidine, (II) (Portilla, Quiroga, de la Torre et al., 2006), and with that of the simpler analogue 7-amino-2,5-dimethylpyrazolo[1,5-a]pyrimidine, which crystallizes as a hemihydrate, (III) (Portilla, Quiroga, Cobo et al., 2006).

The bond distances within the fused heterocyclic system (Table 1) show evidence for electronic delocalization. Thus, within the periphery of the classically localized form (I), the N1═C2 and N4═C5 bonds are both formally double bonds, while C3A—N4 and C7—N7A are both single bonds; however, N1═C2 is not significantly shorter than C3A—N4. Similarly, the C3═C3A and C6═C7 bonds are both formally double bonds, while C2—C3 and C5—C6 are both formally single bonds; however, the C—C distances in the periphery span an overall range of less than 0.02 Å, with no clear distinction between those which are formally single bonds and those which are formally double bonds. These observations, taken all together, point to a significant contribution to the overall molecular–electronic structure from a peripherally delocalized ten-π-electron form.

The molecules of compound (I) are linked by two independent N—H···N hydrogen bonds (Table 2) into a three-dimensional framework structure, whose formation is rather easily analysed in terms of two simple sub-structures, one of which is one-dimensional and the other of which is finite and zero-dimensional.

In the one-dimensional sub-structure, amino atom N7 in the molecule at (x, y, z) acts as a hydrogen-bond donor, via H7A, to the pyrimidine ring atom N4 in the molecule at (−y + 1/2, x − 1/2 + x, z + 1/4), while N7 at (−y + 1/2, x − 1/2, z + 1/4) in turns acts as a donor to N4 at (−x + 1, −y, z + 1/2), so forming a C(6) (Bernstein et al., 1995) helical chain running along the [001] direction and generated by the 4₁ screw axis along (1/2, 0, z) (Fig. 2). The finite sub-structure serves to link the C(6) chains; atom N7 in the molecule at (x, y, z) acts as a hydrogen-bond donor, via H7B, to the pyrazole ring atom N1 in the molecule at (y, x, −z + 1), so forming an R²₂(10) motif generated by the twofold rotation axis along x = y at z = 1/2 (Fig. 3). This motif directly links the C(6) chain along (1/2, 0, z) with the four similar chains along (0, 1/2, z), (0, −1/2, z), (1, −1/2, z) and (1, 1/2, z), and by propagation of this interaction, all of the C(6) chains, and hence all of the molecules, are linked into a single three-dimensional framework structure, built from only two hydrogen bonds.

In the isomeric compound (II), which crystallizes with Z' = 2 in space group P1 (Portilla, Quiroga, de la Torre et al., 2006), the supramolecular structure is only one-dimensional, in contrast to the three-dimensional structure of (I); four independent N—H···N hydrogen bonds link the molecules of (II) into chains containing three different types of centrosymmetric ring, one of R²₂(10) type and two of R⁴₄(14) type. In the hemihydrate (III), which crystallizes in space group C2 (Portilla, Quiroga, Cobo et al., 2006), the components are linked by a combination of O—H···N, N—H···N and N—H···O hydrogen bonds into a complex three-dimensional framework. Hence minor changes in the simple hydrocarbyl substituents in compounds (I)–(III) provoke significant changes both in crystallization behaviour, as manifested in the space groups and Z' values, and in the supramolecular structures.

Experimental top

An intimate mixture of 5-amino-3-tert-butyl-1H-pyrazole (139 mg, 1 mmol) and 3-aminocrotononitrile (82 mg, 1 mmol) was placed in a open Pyrex-glass vessel and irradiated in a domestic microwave oven for 2.5 min at 600 W. The reaction mixture was then extracted with ethanol, and after removal of the solvent, the product (I) was crystallized from ethanol, providing colourless crystals suitable for single-crystal X-ray diffraction (yield 92%, m.p. 489–490 K). MS m/z (%) 204 (100, M⁺), 189 (18).

Computing details top

Data collection: COLLECT (Hooft, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures top

	Fig. 1. A molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A stereoview of part of the crystal structure of (I), showing the formation of a hydrogen-bonded C(6) helical chain generated by the 4₁ screw axis along (1/2, 0, z). For the sake of clarity, H atoms bonded to C atoms have been omitted.
	Fig. 3. Part of the crystal structure of (I), showing the formation of the R²₂(10) motif which links the C(6) helical chains. For the sake of clarity, H atoms bonded to C atoms have been omitted. The atoms marked with an asterisk (*) are at the symmetry position (y, x, −z + 1).

7-Amino-2-tert-butyl-5-methylpyrazolo[1,5-a]pyrimidine top

Crystal data top

C₁₁H₁₆N₄	D_x = 1.162 Mg m⁻³
M_r = 204.28	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4₁2₁2	Cell parameters from 1605 reflections
Hall symbol: P 4abw 2nw	θ = 2.9–27.5°
a = 10.8271 (2) Å	µ = 0.07 mm⁻¹
c = 19.9208 (3) Å	T = 120 K
V = 2335.24 (7) Å³	Block, yellow
Z = 8	0.50 × 0.50 × 0.20 mm
F(000) = 880

Data collection top

Bruker–Nonius KappaCCD diffractometer	1605 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode	1418 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.038
Detector resolution: 9.091 pixels mm^-1	θ_max = 27.5°, θ_min = 2.9°
ϕ and ω scans	h = −14→14
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −13→14
T_min = 0.941, T_max = 0.985	l = −25→25
16594 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.091	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0594P)² + 0.2575P] where P = (F_o² + 2F_c²)/3
1605 reflections	(Δ/σ)_max < 0.001
140 parameters	Δρ_max = 0.14 e Å⁻³
0 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₁₁H₁₆N₄	Z = 8
M_r = 204.28	Mo Kα radiation
Tetragonal, P4₁2₁2	µ = 0.07 mm⁻¹
a = 10.8271 (2) Å	T = 120 K
c = 19.9208 (3) Å	0.50 × 0.50 × 0.20 mm
V = 2335.24 (7) Å³

Data collection top

Bruker–Nonius KappaCCD diffractometer	1605 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	1418 reflections with I > 2σ(I)
T_min = 0.941, T_max = 0.985	R_int = 0.038
16594 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.035	0 restraints
wR(F²) = 0.091	H-atom parameters constrained
S = 1.05	Δρ_max = 0.14 e Å⁻³
1605 reflections	Δρ_min = −0.20 e Å⁻³
140 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.60373 (12)	0.43466 (12)	0.43204 (6)	0.0186 (3)
C2	0.66623 (15)	0.44506 (14)	0.37372 (7)	0.0183 (3)
C21	0.68144 (16)	0.57105 (14)	0.34169 (8)	0.0211 (3)
C22	0.55745 (17)	0.63853 (16)	0.34185 (9)	0.0306 (4)
C23	0.77559 (18)	0.64512 (17)	0.38191 (9)	0.0323 (4)
C24	0.7271 (2)	0.55723 (18)	0.26920 (8)	0.0355 (5)
C3	0.70917 (15)	0.33092 (14)	0.35020 (7)	0.0211 (3)
C3A	0.66825 (15)	0.24374 (15)	0.39590 (7)	0.0188 (3)
N4	0.67679 (13)	0.11919 (12)	0.39836 (6)	0.0218 (3)
C5	0.61991 (16)	0.06367 (15)	0.44939 (7)	0.0211 (3)
C51	0.62832 (19)	−0.07485 (15)	0.45159 (8)	0.0303 (4)
C6	0.55759 (15)	0.12722 (15)	0.50022 (7)	0.0202 (3)
C7	0.55272 (14)	0.25538 (15)	0.49971 (7)	0.0178 (3)
N7	0.50241 (13)	0.32629 (13)	0.54701 (6)	0.0228 (3)
H22A	0.4960	0.5889	0.3179	0.046*
H22B	0.5666	0.7187	0.3195	0.046*
H22C	0.5303	0.6513	0.3883	0.046*
H23A	0.7463	0.6547	0.4282	0.049*
H23B	0.7861	0.7267	0.3614	0.049*
H23C	0.8549	0.6015	0.3820	0.049*
H24A	0.8065	0.5137	0.2690	0.053*
H24B	0.7375	0.6392	0.2491	0.053*
H24C	0.6666	0.5099	0.2432	0.053*
H3	0.7567	0.3163	0.3109	0.025*
H51A	0.6199	−0.1081	0.4061	0.045*
H51B	0.5621	−0.1076	0.4800	0.045*
H51C	0.7085	−0.0992	0.4702	0.045*
H6	0.5184	0.0825	0.5353	0.024*
N7A	0.60580 (12)	0.31054 (12)	0.44492 (6)	0.0169 (3)
H7A	0.4640	0.2868	0.5841	0.027*
H7B	0.5065	0.4133	0.5413	0.027*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0226 (7)	0.0143 (6)	0.0189 (6)	0.0013 (5)	0.0023 (5)	0.0014 (5)
C2	0.0185 (8)	0.0196 (8)	0.0169 (6)	0.0001 (6)	−0.0009 (5)	−0.0008 (6)
C21	0.0242 (8)	0.0196 (8)	0.0193 (7)	−0.0016 (6)	0.0017 (6)	0.0025 (6)
C22	0.0291 (9)	0.0230 (9)	0.0398 (9)	0.0010 (7)	−0.0032 (8)	0.0112 (8)
C23	0.0344 (10)	0.0267 (9)	0.0359 (9)	−0.0069 (8)	−0.0048 (8)	0.0027 (7)
C24	0.0563 (12)	0.0263 (9)	0.0240 (8)	−0.0017 (9)	0.0122 (8)	0.0039 (7)
C3	0.0238 (8)	0.0230 (8)	0.0165 (6)	0.0028 (7)	0.0037 (6)	−0.0010 (6)
C3A	0.0204 (8)	0.0212 (8)	0.0147 (6)	0.0035 (6)	−0.0013 (6)	−0.0024 (6)
N4	0.0297 (8)	0.0178 (6)	0.0179 (6)	0.0052 (6)	0.0003 (5)	−0.0010 (5)
C5	0.0275 (8)	0.0180 (8)	0.0176 (7)	0.0024 (7)	−0.0044 (6)	−0.0008 (6)
C51	0.0489 (11)	0.0187 (8)	0.0232 (7)	0.0035 (8)	0.0007 (8)	−0.0017 (7)
C6	0.0234 (8)	0.0198 (8)	0.0174 (6)	0.0004 (6)	0.0000 (7)	0.0015 (6)
C7	0.0170 (7)	0.0209 (7)	0.0154 (6)	−0.0005 (6)	0.0005 (6)	0.0018 (6)
N7	0.0289 (7)	0.0189 (7)	0.0205 (6)	0.0015 (6)	0.0082 (6)	−0.0001 (5)
N7A	0.0201 (7)	0.0147 (6)	0.0159 (5)	0.0020 (5)	0.0018 (5)	0.0001 (5)

Geometric parameters (Å, º) top

N1—C2	1.3491 (19)	C22—H22C	0.98
C2—C3	1.401 (2)	C23—H23A	0.98
C3—C3A	1.384 (2)	C23—H23B	0.98
C3A—N4	1.353 (2)	C23—H23C	0.98
N4—C5	1.332 (2)	C24—H24A	0.98
C5—C6	1.398 (2)	C24—H24B	0.98
C6—C7	1.389 (2)	C24—H24C	0.98
C7—N7A	1.3705 (19)	C3—H3	0.95
N7A—N1	1.3683 (17)	C5—C51	1.503 (2)
C3A—N7A	1.3906 (18)	C51—H51A	0.98
C2—C21	1.515 (2)	C51—H51B	0.98
C21—C23	1.525 (2)	C51—H51C	0.98
C21—C22	1.528 (2)	C6—H6	0.95
C21—C24	1.534 (2)	C7—N7	1.332 (2)
C22—H22A	0.98	N7—H7A	0.95
C22—H22B	0.98	N7—H7B	0.95

C2—N1—N7A	103.61 (12)	C3A—C3—C2	105.98 (13)
N1—C2—C3	112.38 (13)	C3A—C3—H3	127.0
N1—C2—C21	119.50 (13)	C2—C3—H3	127.0
C3—C2—C21	128.12 (13)	N4—C3A—C3	132.99 (15)
C2—C21—C23	108.96 (13)	N4—C3A—N7A	121.76 (14)
C2—C21—C22	109.51 (13)	C3—C3A—N7A	105.24 (13)
C23—C21—C22	109.55 (14)	C5—N4—C3A	116.49 (14)
C2—C21—C24	110.11 (14)	N4—C5—C6	123.64 (14)
C23—C21—C24	109.30 (15)	N4—C5—C51	116.40 (14)
C22—C21—C24	109.39 (14)	C6—C5—C51	119.95 (14)
C21—C22—H22A	109.5	C5—C51—H51A	109.5
C21—C22—H22B	109.5	C5—C51—H51B	109.5
H22A—C22—H22B	109.5	H51A—C51—H51B	109.5
C21—C22—H22C	109.5	C5—C51—H51C	109.5
H22A—C22—H22C	109.5	H51A—C51—H51C	109.5
H22B—C22—H22C	109.5	H51B—C51—H51C	109.5
C21—C23—H23A	109.5	C7—C6—C5	120.33 (14)
C21—C23—H23B	109.5	C7—C6—H6	119.8
H23A—C23—H23B	109.5	C5—C6—H6	119.8
C21—C23—H23C	109.5	N7—C7—N7A	118.93 (14)
H23A—C23—H23C	109.5	N7—C7—C6	125.90 (14)
H23B—C23—H23C	109.5	N7A—C7—C6	115.17 (14)
C21—C24—H24A	109.5	C7—N7—H7A	118.0
C21—C24—H24B	109.5	C7—N7—H7B	117.9
H24A—C24—H24B	109.5	H7A—N7—H7B	124.1
C21—C24—H24C	109.5	N1—N7A—C7	124.79 (12)
H24A—C24—H24C	109.5	N1—N7A—C3A	112.77 (12)
H24B—C24—H24C	109.5	C7—N7A—C3A	122.45 (13)

N7A—N1—C2—C3	−0.94 (17)	C3A—N4—C5—C51	179.33 (15)
N7A—N1—C2—C21	178.62 (14)	N4—C5—C6—C7	−0.3 (2)
N1—C2—C21—C23	73.54 (18)	C51—C5—C6—C7	177.96 (16)
C3—C2—C21—C23	−106.99 (19)	C5—C6—C7—N7	−176.03 (15)
N1—C2—C21—C22	−46.3 (2)	C5—C6—C7—N7A	3.7 (2)
C3—C2—C21—C22	133.20 (17)	C2—N1—N7A—C7	−179.87 (14)
N1—C2—C21—C24	−166.60 (15)	C2—N1—N7A—C3A	0.02 (17)
C3—C2—C21—C24	12.9 (2)	N7—C7—N7A—N1	−5.0 (2)
N1—C2—C3—C3A	1.50 (18)	C6—C7—N7A—N1	175.21 (14)
C21—C2—C3—C3A	−178.01 (16)	N7—C7—N7A—C3A	175.10 (14)
C2—C3—C3A—N4	176.97 (18)	C6—C7—N7A—C3A	−4.7 (2)
C2—C3—C3A—N7A	−1.36 (17)	N4—C3A—N7A—N1	−177.69 (14)
C3—C3A—N4—C5	−176.66 (17)	C3—C3A—N7A—N1	0.88 (17)
N7A—C3A—N4—C5	1.5 (2)	N4—C3A—N7A—C7	2.2 (2)
C3A—N4—C5—C6	−2.4 (2)	C3—C3A—N7A—C7	−179.23 (14)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N7—H7A···N4ⁱ	0.95	1.97	2.9034 (18)	168
N7—H7B···N1ⁱⁱ	0.95	2.27	3.1202 (19)	149

Symmetry codes: (i) −y+1/2, x−1/2, z+1/4; (ii) y, x, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₁H₁₆N₄
M_r	204.28
Crystal system, space group	Tetragonal, P4₁2₁2
Temperature (K)	120
a, c (Å)	10.8271 (2), 19.9208 (3)
V (Å³)	2335.24 (7)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.50 × 0.50 × 0.20

Data collection
Diffractometer	Bruker–Nonius KappaCCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.941, 0.985
No. of measured, independent and observed [I > 2σ(I)] reflections	16594, 1605, 1418
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.035, 0.091, 1.05
No. of reflections	1605
No. of parameters	140
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.14, −0.20

Computer programs: COLLECT (Hooft, 1999), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997), OSCAIL and SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97 and PRPKAPPA (Ferguson, 1999).

Selected bond lengths (Å) top

N1—C2	1.3491 (19)	C5—C6	1.398 (2)
C2—C3	1.401 (2)	C6—C7	1.389 (2)
C3—C3A	1.384 (2)	C7—N7A	1.3705 (19)
C3A—N4	1.353 (2)	N7A—N1	1.3683 (17)
N4—C5	1.332 (2)	C3A—N7A	1.3906 (18)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N7—H7A···N4ⁱ	0.95	1.97	2.9034 (18)	168
N7—H7B···N1ⁱⁱ	0.95	2.27	3.1202 (19)	149

Symmetry codes: (i) −y+1/2, x−1/2, z+1/4; (ii) y, x, −z+1.

Acknowledgements

X-ray data were collected at the EPSRC National Crystallography Service, University of Southampton, England. JC thanks the Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía, Spain) and the Universidad de Jaén for financial support. JP and JQ thank COLCIENCIAS and UNIVALLE (Universidad del Valle, Colombia) for financial support.

References

Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Ferguson, G. (1999). PRPKAPPA. University of Guelph, Canada. Google Scholar
Hooft, R. W. W. (1999). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
McArdle, P. (2003). OSCAIL for Windows. Version 10. Crystallography Centre, Chemistry Department, NUI Galway, Ireland. Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Portilla, J., Quiroga, J., Cobo, J., Low, J. N. & Glidewell, C. (2006). Acta Cryst. C62, o186–o189. CSD CrossRef CAS IUCr Journals Google Scholar
Portilla, J., Quiroga, J., de la Torre, J. M., Cobo, J., Low, J. N. & Glidewell, C. (2006). Acta Cryst. C62, o521–o524. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2003). SADABS. Version 2.10. University of Göttingen, Germany. Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar

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Volume 63| Part 1| January 2007| Pages o26-o28

doi:10.1107/S0108270106044817

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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

7-Amino-2-tert-butyl-5-methyl­pyrazolo[1,5-a]pyrimidine: a three-dimensional framework structure built from two N—H⋯N hydrogen bonds

Comment

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

organic compounds

7-Amino-2-tert-butyl-5-methylpyrazolo[1,5-a]pyrimidine: a three-dimensional framework structure built from two N—H⋯N hydrogen bonds