Acta Cryst.(2004). E60, o315±o316 DOI: 10.1107/S160053680302974X Zhenfeng Zhanget al. C4H6N2O
o315
organic papers
Acta Crystallographica Section E Structure Reports Online
ISSN 1600-5368
3-Methyl-3-pyrazolin-5-one
Zhenfeng Zhang, Shuo Jin, Siqian Wang, Bo Liu and Jianping Guo*
College of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, People's Republic of China
Correspondence e-mail: [email protected]
Key indicators
Single-crystal X-ray study T= 293 K
Mean(C±C) = 0.005 AÊ Rfactor = 0.043 wRfactor = 0.115 Data-to-parameter ratio = 7.0
For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.
#2004 International Union of Crystallography Printed in Great Britain ± all rights reserved
The title compound, C4H6N2O, is an intermediate in the
further synthesis of theterocyclic compounds. The present crystal structure is orthorhombic (space group Fdd2), and a monoclinic form (P21/a) has been reported by De Camp &
Stewart [(1971).Acta Cryst. B27, 1227±1232].
Comment
In the course of our research on nitrogen heterocycles, we recently needed to prepare several pyrazolin-5-one compounds. Synthetic considerations made 3-methyl-3-pyra-zolin-5-one, (I), and 3-methyl-2-pyra3-methyl-3-pyra-zolin-5-one, (II), the ®rst logical choices. Both (I) and (II) can be readily obtained by the cyclization reaction of ethyl acetoacetate with hydrazine in water at different pH values, these two isomers are inter-convertible. To conduct research on their reaction mechanisms and conformational effects on reactivity, it was necessary for us to complete their X-ray structure analyses.
Unexpectedly, we found polymorphism. In fact, a literature search for (I) showed that its crystal structure was reported early in 1971 (De Camp & Stewart, 1971). The reported structure belongs to the monoclinic space group P21/a [a =
10.520 (3),b= 6.499 (2),c= 8.052 (1) AÊ,= 114.45 (1),Z= 4,
and the solvent used for crystallization was dimethylform-amide]. We report here the orthorhombic form of the title compound, (I).
In (I), the non-H atoms of the molecule are coplanar, with a mean deviation of 0.022 AÊ. The bond lengths and angles are in very good agreement with those found in the monoclinic polymorph and the values lie in expected ranges (Allenet al., 1987). There are intermolecular NÐH O hydrogen bonds, forming an in®nite three-dimensional network (Fig. 2 and Table 2).
Experimental
The preparation of the title compound (I) was carried out by the reaction of ethyl acetoacetate with hydrazine (molar ratio 1:1) in aqueous media at room temperature, for no more than 20 min. Single crystals of (I) were obtained by cooling of the hot solution of the crude product in ethanol (95%) very slowly over 1±2 weeks (yield: 93%, mp 488 K).1HNMR (300 MHz, dmso):10.30 (s, 2H, 2NH),
5.20 (s, 1H, CH ),2.06 (s, 3H, CH3).
Crystal data
C4H6N2O
Mr= 98.11
Orthorhombic,Fdd2
a= 11.722 (2) AÊ
b= 16.945 (3) AÊ
c= 9.898 (2) AÊ
V= 1966.0 (7) AÊ3
Z= 16
Dx= 1.326 Mg mÿ3
MoKradiation Cell parameters from 867
re¯ections
= 5.9±44.4
= 0.10 mmÿ1
T= 293 (2) K Block, colorless 0.300.200.20 mm
Data collection
Bruker Smart CCD diffractometer
!scans
Absorption correction: multi-scan (SADABS; Sheldrick, 1997)
Tmin= 0.557,Tmax= 0.981
1933 measured re¯ections 460 independent re¯ections
439 re¯ections withI> 2(I)
Rint= 0.034 max= 25.0
h=ÿ13!13
k=ÿ20!9
l=ÿ11!11
Re®nement
Re®nement onF2
R[F2> 2(F2)] = 0.043
wR(F2) = 0.115
S= 1.16 460 re¯ections 66 parameters
H-atom parameters constrained
w= 1/[2(F
o2) + (0.063P)2
+ 1.0082P]
whereP= (Fo2+ 2Fc2)/3
(/)max= 0.011
max= 0.13 e AÊÿ3
min=ÿ0.16 e AÊÿ3
Extinction correction:SHELXL
Extinction coef®cient: 0.0020 (8)
Table 1
Selected geometric parameters (AÊ,).
O1ÐC4 1.275 (3) N1ÐC2 1.315 (5) N1ÐN2 1.365 (4)
N2ÐC4 1.324 (4) C2ÐC3 1.368 (5) C3ÐC4 1.403 (5) C2ÐN1ÐN2 108.7 (3)
C4ÐN2ÐN1 109.4 (3) N1ÐC2ÐC3 108.5 (3)
N1ÐC2ÐC1 120.7 (4) C3ÐC2ÐC1 130.7 (4)
Table 2
Hydrogen-bonding geometry (AÊ,).
DÐH A DÐH H A D A DÐH A
N1ÐH1 O1i 0.86 1.93 2.694 (4) 147.9
N2ÐH2 O1ii 0.86 1.81 2.654 (4) 168.6
Symmetry codes: (i)7
4ÿx;yÿ14;14z; (ii)xÿ14;34ÿy;14z.
In the absence of signi®cant anomalous dispersion effects, Friedel pairs were averaged ± the Flack (1983) parameter was ÿ1 (3). H atoms were placed in their idealized positions (NÐH = 0.86, CÐH = 0.93 and 0.96 AÊ;Uiso= 1.2Ueqof the parent atom) and allowed to ride
on the respective parent atoms.
Data collection:SMART(Bruker, 2000); cell re®nement:SAINT
(Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
SHELXTL/PC(Sheldrick, 1999); software used to prepare material for publication:SHELXTL/PC.
This work was under the sponsorship of the National Natural Science Foundation (code: 20372044).
References
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987).J. Chem. Soc. Perkin Trans.2, pp. S1±19.
Bruker (2000).SMART(Version 5.0) andSAINT(Version 6.02). Bruker AXS Inc., Madison, Wisconsin, USA.
De Camp, W. H.. & Stewart, J. M. (1971).Acta Cryst.B27, 1227±1232. Flack, H.D. (1983).Acta Cryst.A39, 876±881.
Sheldrick, G. M. (1997).SADABS,SHELXS97 andSHELXL97. University of GoÈttingen, Germany.
Sheldrick, G. M. (1999). SHELXTL/PC. Version 6.10. Bruker AXS Inc., Madison, Wisconsin, USA.
Figure 2
Packing diagram of (I), viewed down thebaxis. Dashed lines indicate hydrogen bonds.
Figure 1
supporting information
sup-1 Acta Cryst. (2004). E60, o315–o316
supporting information
Acta Cryst. (2004). E60, o315–o316 [https://doi.org/10.1107/S160053680302974X]
3-Methyl-3-pyrazolin-5-one
Zhenfeng Zhang, Shuo Jin, Siqian Wang, Bo Liu and Jianping Guo
3-Methyl-3-Pyrazolin-5-one
Crystal data
C4H6N2O
Mr = 98.11
Orthorhombic, Fdd2 a = 11.722 (2) Å b = 16.945 (3) Å c = 9.898 (2) Å V = 1966.0 (7) Å3
Z = 16 F(000) = 832
Dx = 1.326 Mg m−3
Melting point: 215 K
Mo Kα radiation, λ = 0.71073 Å Cell parameters from 867 reflections θ = 5.9–44.4°
µ = 0.10 mm−1
T = 293 K Block, colorless 0.30 × 0.20 × 0.20 mm
Data collection
Smart CCD diffractometer
Radiation source: fine-focus sealed tube Graphite monochromator
ω scan
Absorption correction: multi-scan (SADABS; Sheldrick, 1997) Tmin = 0.557, Tmax = 0.981
1933 measured reflections 460 independent reflections 439 reflections with I > 2σ(I) Rint = 0.034
θmax = 25.0°, θmin = 3.0°
h = −13→13 k = −20→9 l = −11→11
Refinement
Refinement on F2
Least-squares matrix: full R[F2 > 2σ(F2)] = 0.043
wR(F2) = 0.115
S = 1.16 460 reflections 66 parameters 1 restraint
Primary atom site location: structure-invariant direct methods
Secondary atom site location: difference Fourier map
Hydrogen site location: inferred from neighbouring sites
H-atom parameters constrained w = 1/[σ2(F
o2) + (0.063P)2 + 1.0082P]
where P = (Fo2 + 2Fc2)/3
(Δ/σ)max = 0.011
Δρmax = 0.13 e Å−3
Δρmin = −0.16 e Å−3
Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Extinction coefficient: 0.0020 (8) Absolute structure: see text
Special details
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 (Å2)
x y z Uiso*/Ueq
O1 0.9969 (2) 0.38889 (15) 0.3766 (3) 0.0597 (9) N1 0.9383 (3) 0.21227 (16) 0.5257 (3) 0.0489 (9)
H1 0.8992 0.1829 0.5794 0.059*
N2 0.9171 (3) 0.28983 (16) 0.4984 (3) 0.0464 (9)
H2 0.8611 0.3168 0.5303 0.056*
C1 1.0662 (5) 0.1058 (2) 0.4573 (6) 0.0750 (15)
H1A 1.0528 0.0834 0.5450 0.113*
H1B 1.1461 0.1031 0.4366 0.113*
H1C 1.0240 0.0767 0.3907 0.113*
C2 1.0284 (3) 0.1899 (2) 0.4565 (4) 0.0456 (9) C3 1.0689 (3) 0.2535 (2) 0.3862 (4) 0.0481 (10)
H3 1.1326 0.2545 0.3301 0.058*
C4 0.9962 (3) 0.3171 (2) 0.4151 (4) 0.0435 (9)
Atomic displacement parameters (Å2)
U11 U22 U33 U12 U13 U23
O1 0.0520 (15) 0.0400 (15) 0.087 (2) 0.0018 (12) 0.0107 (14) 0.0231 (14) N1 0.068 (2) 0.0273 (15) 0.0514 (18) −0.0046 (13) 0.0136 (16) 0.0091 (13) N2 0.0478 (17) 0.0296 (15) 0.062 (2) 0.0035 (12) 0.0154 (14) 0.0064 (13) C1 0.101 (4) 0.043 (2) 0.081 (3) 0.025 (2) 0.008 (3) 0.003 (2) C2 0.055 (2) 0.040 (2) 0.0419 (17) 0.0078 (16) −0.0005 (16) −0.0021 (16) C3 0.041 (2) 0.053 (2) 0.0502 (19) 0.0032 (16) 0.0044 (16) 0.0086 (17) C4 0.0385 (17) 0.041 (2) 0.051 (2) 0.0032 (14) 0.0016 (16) 0.0068 (17)
Geometric parameters (Å, º)
O1—C4 1.275 (3) C1—H1A 0.9600
N1—C2 1.315 (5) C1—H1B 0.9600
N1—N2 1.365 (4) C1—H1C 0.9600
N1—H1 0.8600 C2—C3 1.368 (5)
N2—C4 1.324 (4) C3—C4 1.403 (5)
N2—H2 0.8600 C3—H3 0.9300
C1—C2 1.493 (4)
C2—N1—N2 108.7 (3) H1B—C1—H1C 109.5
C2—N1—H1 125.7 N1—C2—C3 108.5 (3)
N2—N1—H1 125.7 N1—C2—C1 120.7 (4)
C4—N2—N1 109.4 (3) C3—C2—C1 130.7 (4)
supporting information
sup-3 Acta Cryst. (2004). E60, o315–o316
N1—N2—H2 125.3 C2—C3—H3 126.6
C2—C1—H1A 109.5 C4—C3—H3 126.6
C2—C1—H1B 109.5 O1—C4—N2 121.6 (3)
H1A—C1—H1B 109.5 O1—C4—C3 131.8 (3)
C2—C1—H1C 109.5 N2—C4—C3 106.6 (3)
H1A—C1—H1C 109.5
Hydrogen-bond geometry (Å, º)
D—H···A D—H H···A D···A D—H···A
N1—H1···O1i 0.86 1.93 2.694 (4) 148
N2—H2···O1ii 0.86 1.81 2.654 (4) 169