2-Bromo-5-methoxy­benzohydrazide

In the title compound, C₈H₉BrN₂O₂, the amide bond is in a cis configuation. The N—N—C=O group is planar [torsion angle 0.6 (6)°] and forms a dihedral angle of 46.4 (2)° with the aromatic ring. The crystal packing is stabilized by two strong and one rather weak N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.046
• wR factor = 0.116
• Data-to-parameter ratio = 16.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.95
PLAT420_ALERT_2_C D-H Without Acceptor       N2     -   H2A    ...          ?
PLAT480_ALERT_4_C Long H...A H-Bond Reported H2A    ..  O2      ..       2.61 Ang.

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.57
           From the CIF: _reflns_number_total               2135
           Count of symmetry unique reflns         1278
           Completeness (_total/calc)            167.06%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       857
           Fraction of Friedel pairs measured     0.671
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   1 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
   0 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Hydrazides are useful precursors in the synthesis of several heterocyclic systems (Narayana, Vijayaraj et al., 2005; Narayana, Ashalatha et al., 2005). Some substituted hydrazides are reported to exhibit carcinostatic activity (Cajocorius et al., 1977) against several types of tumors and also possess antimicrobial activity (Swain, 1959 & Liu et al., 2006). They are also used as intermediates in many pharmaceutically important compounds. Structures of maleic hydrazide (Katrusiak, 1993), isonicotinic acid hydrazide (Bhat et al., 1974) and N,N-dimethyl-N'-(o-fluorobenzoyl)hydrazide (Muir & Morris, 2003) have been reported. Recently the structure of 2-bromo-N'-isopropylidene-5-methoxybenzohydrazide was reported (Sarojini et al., 2007). In view of the importance of hydrazides, a new hydrazide, (I), C₈H₉BrN₂O₂, has been synthesized and its crystal structure is reported.

Geometric parameters of the title compound are in the usual ranges. The amide bond is in a cis conformation. The N—N—C=O moiety is planar [torsion angle N2—N1—C7—O1 0.6 (6)°] and forms a dihedral angle of 46.4 (2)° with the aromatic ring. The crystal packing is stabilized by two strong and one rather weak N—H···O hydrogen bonds.

Related literature

For related structures, see: Anitha et al. (2005); Freeman & Bugg (1974); Jethmalani et al. (1996); Yathirajan et al. (2007). For related literature, see: Kagabu et al. (1998); Aranda & Morlock (2006). None of the refs in this (the original) Related literature section have been provided and none are mentioned elsewhere; shoud this be replaced with the following?

For related literature, see: Bhat et al. (1974); Cajocorius et al. (1977); Katrusiak (1993); Liu et al. (2006); Muir & Morris (2003); Narayana, Ashalatha et al. (2005); Narayana, Vijayaraj et al. (2005); Sarojini et al. (2007); Swain (1959).

S2. Experimental

A mixture of ethyl 2-bromo-5-methoxybenzoate (25.9 g, 0.1 mol) and 5.5 ml of hydrazine hydrate in 100 ml of ethanol was refluxed over water bath for 4 h. The precipitate formed was filtered and recrystallized from a mixture (8:2) of ethanol and toluene (m.p.:433–435 K). Analysis for C₈H₉BrN₂O₂: Found (Calculated): C: 39.14 (39.21); H: 3.66 (3.70); N: 11.39% (11.43%).

S3. Refinement

H atoms were refined with fixed individual displacement parameters [U(H) = 1.2 U_eq(C,N) or U(H) = 1.5 U_eq(C_methyl)] using a riding model with C—H(aromatic) = 0.95 Å or C—H(methyl) = 0.98 Å, respectively. The methyl group was allowed to rotate but not to tip. The coordinates of the amino H atoms were refined.

Computing details

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. Perspective view of the title compound with the atom numbering; displacement ellipsoids are plotted at the 50% probability level.

2-Bromo-5-methoxybenzohydrazide

Crystal data

C8H9BrN2O2	F(000) = 488
Mr = 245.08	Dx = 1.759 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 6028 reflections
a = 5.0150 (5) Å	θ = 3.7–27.1°
b = 11.4093 (10) Å	µ = 4.41 mm^−1
c = 16.1736 (14) Å	T = 173 K
V = 925.42 (15) Å^3	Block, colourless
Z = 4	0.32 × 0.27 × 0.23 mm

Data collection

Stoe IPDSII two-circle diffractometer	2135 independent reflections
Radiation source: fine-focus sealed tube	2008 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.070
ω scans	θmax = 27.6°, θmin = 3.6°
Absorption correction: multi-scan (MULABS; Spek, 2003; Blessing, 1995)	h = −6→5
Tmin = 0.263, Tmax = 0.380	k = −14→14
7646 measured reflections	l = −21→21

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.046	w = 1/[σ^2(Fo^2) + (0.0796P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.116	(Δ/σ)max < 0.001
S = 1.04	Δρmax = 0.95 e Å^−3
2135 reflections	Δρmin = −0.94 e Å^−3
129 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.025 (4)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 862 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: −0.014 (17)

Special details

Experimental. ;

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.

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

	x	y	z	Uiso*/Ueq
Br1	1.19431 (9)	0.27433 (4)	0.41643 (3)	0.02729 (19)
O1	1.0833 (6)	0.5462 (3)	0.4178 (2)	0.0235 (6)
O2	0.4447 (7)	0.3871 (3)	0.13391 (18)	0.0249 (7)
N1	0.6358 (7)	0.5633 (3)	0.4286 (2)	0.0173 (7)
H1	0.471 (12)	0.537 (5)	0.414 (4)	0.021*
N2	0.6506 (8)	0.6559 (3)	0.4876 (2)	0.0207 (7)
H2A	0.694 (13)	0.714 (5)	0.462 (4)	0.025*
H2B	0.799 (13)	0.634 (5)	0.518 (3)	0.025*
C1	0.8142 (9)	0.4236 (3)	0.3314 (2)	0.0163 (7)
C2	0.9609 (9)	0.3205 (4)	0.3285 (3)	0.0211 (8)
C3	0.9408 (10)	0.2434 (4)	0.2620 (3)	0.0250 (9)
H3	1.0455	0.1740	0.2604	0.030*
C4	0.7651 (9)	0.2693 (4)	0.1979 (3)	0.0240 (9)
H4	0.7510	0.2179	0.1519	0.029*
C5	0.6095 (9)	0.3707 (4)	0.2009 (2)	0.0196 (8)
C6	0.6336 (8)	0.4478 (4)	0.2672 (2)	0.0168 (8)
H6	0.5279	0.5168	0.2690	0.020*
C7	0.8561 (9)	0.5152 (4)	0.3976 (2)	0.0165 (8)
C8	0.2815 (11)	0.4903 (4)	0.1332 (3)	0.0266 (10)
H8A	0.1511	0.4860	0.1782	0.040*
H8B	0.1878	0.4958	0.0801	0.040*
H8C	0.3941	0.5597	0.1407	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0261 (3)	0.0310 (3)	0.0248 (2)	0.00662 (19)	−0.00015 (18)	0.00917 (16)
O1	0.0107 (13)	0.0321 (15)	0.0278 (15)	−0.0018 (12)	0.0003 (14)	−0.0065 (14)
O2	0.0269 (18)	0.0347 (17)	0.0130 (13)	0.0016 (15)	−0.0039 (12)	−0.0064 (12)
N1	0.0085 (17)	0.0267 (17)	0.0167 (15)	−0.0009 (13)	−0.0030 (12)	−0.0070 (13)
N2	0.0200 (19)	0.0257 (18)	0.0163 (15)	−0.0004 (15)	−0.0033 (14)	−0.0070 (13)
C1	0.0131 (18)	0.0242 (18)	0.0114 (15)	−0.0030 (17)	0.0014 (16)	0.0010 (13)
C2	0.022 (2)	0.0241 (19)	0.0177 (17)	−0.0023 (17)	0.0042 (16)	0.0059 (16)
C3	0.028 (2)	0.0171 (19)	0.030 (2)	0.0057 (16)	0.0073 (19)	0.0016 (16)
C4	0.025 (2)	0.0252 (19)	0.0213 (18)	−0.0005 (18)	0.0056 (16)	−0.0063 (16)
C5	0.017 (2)	0.028 (2)	0.0132 (16)	−0.0017 (17)	0.0026 (14)	−0.0052 (15)
C6	0.014 (2)	0.0214 (18)	0.0152 (17)	0.0000 (14)	0.0047 (14)	−0.0030 (14)
C7	0.015 (2)	0.0218 (18)	0.0132 (17)	0.0011 (15)	0.0011 (14)	0.0016 (13)
C8	0.025 (2)	0.034 (2)	0.0202 (18)	0.002 (2)	−0.0069 (18)	−0.0035 (16)

Geometric parameters (Å, º)

Br1—C2	1.916 (4)	C1—C7	1.511 (5)
O1—C7	1.237 (6)	C2—C3	1.393 (6)
O2—C5	1.376 (5)	C3—C4	1.393 (6)
O2—C8	1.434 (6)	C3—H3	0.9500
N1—C7	1.332 (5)	C4—C5	1.396 (6)
N1—N2	1.426 (5)	C4—H4	0.9500
N1—H1	0.91 (6)	C5—C6	1.391 (5)
N2—H2A	0.81 (6)	C6—H6	0.9500
N2—H2B	0.92 (6)	C8—H8A	0.9800
C1—C2	1.388 (6)	C8—H8B	0.9800
C1—C6	1.405 (6)	C8—H8C	0.9800
C5—O2—C8	117.5 (3)	C3—C4—H4	119.9
C7—N1—N2	121.0 (3)	C5—C4—H4	119.9
C7—N1—H1	121 (4)	O2—C5—C6	125.0 (4)
N2—N1—H1	118 (4)	O2—C5—C4	114.9 (4)
N1—N2—H2A	107 (4)	C6—C5—C4	120.1 (4)
N1—N2—H2B	101 (3)	C5—C6—C1	120.1 (4)
H2A—N2—H2B	106 (6)	C5—C6—H6	120.0
C2—C1—C6	118.9 (4)	C1—C6—H6	120.0
C2—C1—C7	122.5 (4)	O1—C7—N1	123.1 (4)
C6—C1—C7	118.5 (4)	O1—C7—C1	120.9 (4)
C1—C2—C3	121.6 (4)	N1—C7—C1	115.9 (4)
C1—C2—Br1	122.1 (3)	O2—C8—H8A	109.5
C3—C2—Br1	116.3 (3)	O2—C8—H8B	109.5
C2—C3—C4	119.1 (4)	H8A—C8—H8B	109.5
C2—C3—H3	120.5	O2—C8—H8C	109.5
C4—C3—H3	120.5	H8A—C8—H8C	109.5
C3—C4—C5	120.2 (4)	H8B—C8—H8C	109.5
C6—C1—C2—C3	2.7 (6)	O2—C5—C6—C1	−178.2 (4)
C7—C1—C2—C3	−172.7 (4)	C4—C5—C6—C1	−0.2 (6)
C6—C1—C2—Br1	−175.7 (3)	C2—C1—C6—C5	−1.9 (6)
C7—C1—C2—Br1	9.0 (6)	C7—C1—C6—C5	173.7 (4)
C1—C2—C3—C4	−1.4 (7)	N2—N1—C7—O1	0.6 (6)
Br1—C2—C3—C4	177.1 (3)	N2—N1—C7—C1	−176.0 (3)
C2—C3—C4—C5	−0.7 (7)	C2—C1—C7—O1	45.0 (6)
C8—O2—C5—C6	−1.4 (6)	C6—C1—C7—O1	−130.4 (4)
C8—O2—C5—C4	−179.5 (4)	C2—C1—C7—N1	−138.3 (4)
C3—C4—C5—O2	179.7 (4)	C6—C1—C7—N1	46.3 (5)
C3—C4—C5—C6	1.5 (7)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.91 (6)	1.95 (6)	2.783 (5)	152 (5)
N2—H2A···O2^ii	0.81 (6)	2.61 (6)	3.324 (5)	148 (6)
N2—H2B···O2^iii	0.92 (6)	2.29 (6)	3.156 (5)	156 (5)

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