Five N'-benzylidene-N-methylpyrazine-2-carbohydrazides

organic compounds

Acta Crystallographica Section C

Crystal Structure

Communications

A recently reported study of mono- and diesters of

3-(pyrazin-2-ylcarbonyl)dithiocarbazic acid suggested that the

planarity of pyrazine derivatives may be a prerequisite for

tubercolostatic activity (Szczesio et al., 2011; Orlewska et al.,

2001). This prompted crystal structure determinations of the

ﬁve title methylated pyrazine-2-carbohydrazide derivatives,

namely N⁰-benzylidene-N-methylpyrazine-2-carbohydrazide,

(IIa) (Fig. 1), N⁰-(2-methoxybenzylidene)-N-methylpyrazine-

2-carbohydrazide, (IIb) (Fig. 2), N⁰-(4-cyanobenzylidene)-N-

methylpyrazine-2-carbohydrazide dihydrate, (IIc) (Fig. 3),

N-methyl-N⁰-(2-nitrobenzylidene)pyrazine-2-carbohydrazide,

(IId) (Fig. 4), and N-methyl-N⁰-(4-nitrobenzylidene)pyrazine-

2-carbohydrazide, (IIe) (Fig. 5). A comparative analysis of the

structures of these inactive compounds on the one hand with,

ISSN 0108-2701

Five N⁰-benzylidene-N-methyl-

pyrazine-2-carbohydrazides

Ligia R. Gomes,^aJohn Nicolson Low,^b* Ana S. M. C.

Rodrigues,^cJames L. Wardell,^b,dCamillo H. da Silva Lima^d

and Marcus V. N. de Souza^d

a

´

ˆ

REQUIMTE, Departamento de Quımica e Bioquımica, Faculdade de Ciencias,

Universidade do Porto, Rua do Campo Alegre 687, P-4169-007 Porto, Portugal,

^bDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen

c

´

AB24 3UE, Scotland, Centro de Investiga¸cao em Quımica, Departamento de

˜

ˆ

´

Quımica e Bioquımica, Faculdade de Ciencias, Universidade do Porto, Rua do

d

´

Campo Alegre 687, P-4169-007 Porto, Portugal, and Instituto de Tecnologıa em

´

Farmacos–Farmangunhos, FioCruz – Funda¸cao Oswaldo Cruz, R. Sizenando

˜

Nabuco 100, Manguinhos, 21041-250 Rio de Janeiro, RJ, Brazil

Correspondence e-mail: jnlow111@gmail.com

Received 2 April 2013

Accepted 11 April 2013

The compounds N⁰-benzylidene-N-methylpyrazine-2-carbo-

hydrazide, C₁₃H₁₂N₄O, (IIa), N⁰-(2-methoxybenzylidene)-N-

methylpyrazine-2-carbohydrazide, C₁₄H₁₄N₄O₂, (IIb), N⁰-(4-

cyanobenzylidene)-N-methylpyrazine-2-carbohydrazide dihy-

drate, C₁₄H₁₁N₅Oꢀ2H₂O, (IIc), N-methyl-N⁰-(2-nitrobenzyl-

idene)pyrazine-2-carbohydrazide, C₁₃H₁₁N₅O₃, (IId), and

N-methyl-N⁰-(4-nitrobenzylidene)pyrazine-2-carbohydrazide,

C₁₃H₁₁N₅O₃, (IIe), have dihedral angles between the pyrazine

rings and the benzene rings in the range 55–78^ꢁ. These

methylated pyrazine-2-carbohydrazides have supramolecular

structures which are formed by weak C—Hꢀ ꢀ ꢀO/N hydrogen

bonds, with the exception of (IIc) which is hydrated. There are

ꢀ–ꢀ stacking interactions in all ﬁve compounds. Three of these

structures are compared with their nonmethylated counter-

parts, which have dihedral angles between the pyrazine rings

and the benzene rings in the range 0–6^ꢁ.

on the other, those of moderately active N⁰-benzylidene-

pyrazine-2-carbohydrazide, (Ib) (de Souza et al., 2011), N⁰-(4-

cyanobenzylidene)pyrazine-2-carbohydrazide, (Ic) (Howie et

al., 2010a), and N⁰-(2-nitrobenzylidene)pyrazine-2-carbohy-

drazide, (Id) (Howie et al., 2010a), will be a useful contribution

to the understanding of the correlation between structure and

activity.

Comment

Pyrazine derivatives exhibit a wide range of biological activ-

ities. Recent studies have revealed that pyrazine-2-carbo-

hydrazides, (I) (see Scheme; Vergara et al., 2009; Lima et al.,

2011), have moderate antituberculosis properties. The crystal

structures of various pyrazine-2-carbohydrazides have been

reported (Baddeley et al., 2009; Howie et al., 2010a,b,c; Howie,

de Souza et al., 2010; de Souza et al., 2011). In continuation of

these studies, the synthesis and antituberculosis activities of a

series of methylated pyrazine-2-carbohydrazide derivatives,

(II) (see Scheme), have been studied. It is worth noting that

methylation of (I) occurred at the imine N atom rather than at

the pyridine N atom. However, none of the compounds (II)

was found to exhibit antituberculosis properties (de Souza,

2013).

Figure 1

The molecular structure of (IIa), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 30% probability level.

Acta Cryst. (2013). C69, 549–555

doi:10.1107/S0108270113010056

# 2013 International Union of Crystallography 549

organic compounds

Figure 5

The molecular structure of (IIe), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 30% probability level.

Figure 2

The molecular structure of (IIb), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 30% probability level. The

dashed lines show the minor disorder component of the pyrazine ring.

group trans to the H—N(pyrazinamide) bond, shown as

conformation E(1) in Fig. 6. Furthermore, a short intra-

molecular pyrazine–hydrazide ortho-Nꢀ ꢀ ꢀH—N⁰contact is

observed for the majority of these structures [see, for example,

Baddeley et al. (2009), Howie et al. (2010a,b,c), Howie, de

Souza et al. (2010) and de Souza et al. (2011)]. These two

effects constrain the relative positions of the pyrazine N atoms

with respect to the hydrazine group. Hyperconjugation from

the heteroaryl ring to the benzene ring via the hydrazine unit

has been suggested as the main contributor to the near

planarity of type (I) compounds and this is reinforced by the

intramolecular N—Hꢀ ꢀ ꢀN hydrogen bond (Szczesio et al.,

2011). However, this planarity can be dramatically inﬂuenced

by the nature and position of the substituents on the benzene

ring.

Figure 3

The molecular structure of (IIc), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 30% probability level. Dashed

lines indicate hydrogen bonding to the solvent water molecules.

Figure 4

The molecular structure of (IId), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 30% probability level.

Figure 6

The conformations of N⁰-[(E)-aryl]pyrazine-2-carbohydrazides, where

E(1) and E(2) are the trans and cis arrangements of the C O and H—N2

bonds, respectively. The E(1) form is preferred by N⁰-arylpyrazine-2-

carbohydrazides (de Souza et al., 2011; Howie et al., 2010a) and the E(2)

form is adopted by the N-methyl-N⁰-arylpyrazine-2-carbohydrazides

characterized in this study.

As will be shown, derivatives (IIa)–(IIe) are not planar,

unlike the analogous compounds (Ib)–(Id). A search of the

Cambridge Structural Database (CSD, Version 5.34; Allen,

2002) revealed that pyrazine-2-carbohydrazides of type (I)

exhibit a preference for conformations having the carbonyl

ꢂ

550 Gomes et al. C₁₃H₁₂N₄O and four analogues

Acta Cryst. (2013). C69, 549–555

organic compounds

C22—C2 bond is probably due to the participation of atom

C25 as a donor in an intermolecular hydrogen bond.

Compound (IIb) exhibits conformational disorder. The

pyrazine ring is rotated anticlockwise by 51.10 (3)^ꢁfor the

major component and clockwise by 67.14 (3)^ꢁfor the minor

one. These rotations are based on the torsion angle ’₁in

Table 1 for both the major and minor components. It is

interesting to note that atom N21 of the major component

participates as an acceptor in a weak Nꢀ ꢀ ꢀH—C inter-

molecular interaction, while the equivalent interaction is

absent in the minor component.

Compound (IIc) crystallizes as a dihydrate. The asymmetric

unit was selected such that the three molecules form a

hydrogen-bonded unit. The water molecules are involved in

hydrogen-bonded chains with atoms N21.

In compound (IId), the plane of the benzene ring is prac-

tically coplanar with the plane of the CNNC spacer group, the

dihedral angle being 5.3 (3)^ꢁ. The dihedral angle between the

plane of the CNNC spacer group and the mean plane of the

pyrazine ring is 53.0 (2)^ꢁ, a clockwise rotation, with reference

to atom N21, around the C2—C22 axis. The nitro group is

twisted out of the plane of the benzene ring by 45.8 (4)^ꢁ. In

spite of this, there is a short contact between atoms O121 and

ꢁ

˚

H1 of 2.40 A, with an angle at atom H1 of 112 . The twist of

this nitro group may result as a compromise between this weak

intramolecular interaction and a weak intermolecuar inter-

action involving atom O122 of the nitro group.

Figure 7

Part of the crystal structure of (IIa), showing the chain which runs parallel

to the b axis. Atoms labelled with an asterisk (*) or a hash symbol (#) are

at the symmetry positions (x, y ꢃ 1, z) and (x, y + 1, z), respectively. H

atoms not involved in hydrogen bonding (dashed lines) have been

omitted.

In isomeric compound (IIe), the dihedral angle between the

benzene-ring mean plane and the CNNC spacer group is

8.26 (17)^ꢁ, and the dihedral angle between the CNNC spacer

group and the mean plane of the pyrazine ring is 59.65 (17)^ꢁ,

again a clockwise rotation, with reference to atom N21,

around the C2—C22 axis. In contrast with (IId), the nitro

substituent is twisted out of the plane of the benzene ring

plane by only 7.1 (2)^ꢁ.

Only in hydrated (IIc) are strong hydrogen bonds present.

For the other compounds studied here, the intermolecular

arrangements are formed by weak C—Hꢀ ꢀ ꢀO/N hydrogen

bonds and ꢀ–ꢀ stacking interactions.

As expected, the substitution of a methyl group on N2 in the

pyrazine-2-carbohydrazide system induces signiﬁcant struc-

tural change. The major changes are in the relative positions of

the pyrazine ring and carbonyl groups, and in the nonplanarity

of the methylated compounds. The methyl group precludes the

formation of the intramolecular hydrogen bond observed in

the compounds of type (I) and imposes steric hindrance near

the pyrazine ring, with the result that the conformation of the

compounds of type (II) is E(2) (Fig. 6), in contrast with the

E(1) conformation assumed by nonmethylated compounds

(I). The overall planarity is lost, probably due to the loss of

hyperconjugation within the C(O)NMeN C group. The

deviations from planarity of (IIa)–(IIe) arise fundamentally

from the rotation of the pyrazine (py) ring about the C(py)—

C( O) axis. Various torsion and other angles determined for

(I) and (II) are listed in Table 1. The molecule of (Ib) (de

Souza et al., 2011) is planar and lies on a crystallographic

mirror plane, while that of (Ic) (Howie et al., 2010a) is nearly

planar [ꢁ = 5.82 (7)^ꢁ]. In contrast, ꢁ values for compounds (II)

are in the range 55–78^ꢁ(Table 1). The rotation of the pyrazine

ring about the C22—C2 axis is the main contributor to the

nonplanarity of the methylated compounds, since the benzene

rings are largely coplanar with the CNNC spacer group.

Compound (IIa) exhibits the largest dihedral angle and the

greatest deviation of atom C2 from the mean plane through

the pyrazine ring. The angle the pyrazine ring makes with the

For compound (IIa), a weak C25–H25ꢀ ꢀ ꢀO2(x, y ꢃ 1, z)

hydrogen bond links the molecules into a C(7) chain (Bern-

stein et al., 1995), which runs parallel to the b axis (Table 2 and

Fig. 7). There is a ꢀ–ꢀ short contact between the pyrazine

1

rings, lying across the centre of symmetry at (¹₂, , ); the

2

˚

centroid–centroid distance is 3.6631 (7) A, the perpendicular

˚

distance between the rings is 3.6415 (5) A and the slippage is

˚

0.395 A.

In compound (IIb), the intermolecular short contacts

(Table 3) involve atom C13 as a donor and atom N21 of the

major disordered pyrazine ring as an acceptor. There are no

similar contacts for the minor component. This suggests that

this interaction does not play any signiﬁcant part in the

supramolecular structure of this compound. The other short

intermolecular contacts involve the methyl H atoms (Table 3).

There is a ꢀ–ꢀ short contact between the pyrazine rings, which

stack above each other with unit translation along the a axis;

for the major component, the centroid–centroid distance is

ꢂ

Acta Cryst. (2013). C69, 549–555

Gomes et al.

C₁₃H₁₂N₄O and four analogues 551

organic compounds

Figure 9

A stereoview of (IId), showing the ribbon structure formed by the linking

of centrosymmetric dimers. This ribbon runs parallel to the (101) plane. H

atoms not involved in hydrogen bonding (dashed lines) have been

omitted.

Figure 8

A stereoview of (IIc), showing the structure formed by the rings

generated by the water chain, which runs parallel to the b axis. H atoms

not involved in hydrogen bonding (dashed lines) have been omitted.

˚

4.032 (7) A, the perpendicular distance between the rings is

˚

3.600 (3) A and the slippage is 1.816 A, while for minor

˚

component, the centroid–centroid distance is 4.033 (8) A, the

˚

perpendicular distance between the rings is 3.164 (4) A and

˚

the slippage is 2.500 A. The benzene rings also stack above

each other with unit translation along the a axis; the centroid–

˚

centroid distance is 4.032 (6) A, the perpendicular distance

˚

between the rings is 3.4489 (9) A and the slippage is 2.088 A.

For compound (IIc), water molecule O1W links the mol-

ecules into a C₂²(7) chain via O1W—H1WBꢀ ꢀ ꢀN21 (within the

deﬁned asymmetric unit) and O1W—H1WAꢀ ꢀ ꢀO2(x, y ꢃ 1, z)

hydrogen bonds. This chain runs parallel to the b axis. The

O2W water molecules are linked into a C2 chain by an O2—

Figure 10

A stereoview of (IIe), showing the double-sided sheet which runs parallel

to the (101) plane. H atoms not involved in hydrogen bonding (dashed

lines) have been omitted.

˚

cular distance between the rings is 3.3838 (15) A and the

˚

slippage is 1.723 A. The benzene rings also stack above each

other with unit translation along the a axis; the centroid–

1

H2WBꢀ ꢀ ꢀO2W(ꢃx + 1, y ꢃ , ꢃz + ) hydrogen bond. This

2

chain of water molecules links two antiparallel chains together

to form a ribbon which runs parallel to the b axis (Table 4 and

Fig. 8). These chains are linked into a three-dimensional

˚

centroid distance is 3.797 (2) A, the perpendicular distance

˚

between the rings is 3.5009 (14) A and the slippage is 2.471 A,

For compound (IIe), a C15—H15ꢀ ꢀ ꢀO2(x + ¹₂, ꢃy + ₂¹, z + ₂¹)

hydrogen bond links the molecules into a C(9) chain. The

molecules are linked across a centre of symmetry at (¹₂, ₂¹, ₂¹) by

a C23—H23ꢀ ꢀ ꢀO2(ꢃx + 1, ꢃy + 1, ꢃz + 1) hydrogen bond.

These two interactions combine the molecules into a double-

sided sheet which runs parallel to the (101) plane (Fig. 10 and

Table 6). The pyrazine rings stack above each other across a

centre of symmetry at (¹₂, 0, ₂¹); the centroid–centroid distance

1

structure by weak C13—H13ꢀ ꢀ ꢀO1W(x, ꢃy + , z + ) and

2

C26—H26ꢀ ꢀ ꢀN141(x, ꢃy + ¹₂, ꢃz ꢃ ₂¹) hydrogen bonds

(Table 4). There is a ꢀ–ꢀ short contact between the pyrazine

rings, which stack above each other along the b axis; the

˚

centroid–centroid distance is 3.9517 (15) A, the perpendicular

˚

distance between the rings is 3.5627 (10) A and the slippage is

˚

1.710 A. The benzene rings also stack above each other with

unit translation along the a axis; the centroid–centroid

˚

distance is 3.9516 (15) A, the perpendicular distance between

˚

is 4.1331 (7) A, the perpendicular distance between the rings is

˚

3.4738 (11) A and the slippage is 2.240 A.

˚

the rings is 3.4128 (10) A and the slippage is 2.088 A.

˚

For compound (IId), a weak C14—H14ꢀ ꢀ ꢀO2(x + 1, y, z ꢃ 1)

hydrogen bond links the molecules into a C(10) chain, which is

formed by unit translations along the a and c axes; this chain

and a centrosymetrically antiparallel chain are linked by a

C13—H13ꢀ ꢀ ꢀO122(ꢃx + 2, ꢃy + 1, ꢃz) hydrogen bond and its

centrosymetrically related bond, so forming an R²₂(10) ring,

linking the molecules into ribbons which lie parallel to (101)

(Fig. 9 and Table 5). There is a ꢀ–ꢀ short contact between the

pyrazine rings, which stack above each other along the a axis;

Experimental

A reaction mixture of the appropriate N⁰-[(E)-benzylidene]pyrazine-

2-carbohydrazide derivative (0.75 mmol; Vergara et al., 2009; Lima et

al., 2011), Na₂CO₃(ca 4 mmol) and MeI (3 mmol) in acetone (4 ml)

was heated at 313 K for 18 h under a nitrogen atmosphere. The

reaction mixture was ﬁltered and the ﬁltrate was concentrated under

reduced pressure to leave a residue, which was added to ice–water.

The solid which separated was collected and washed with cold Et₂O

(3 ꢄ 10 ml), yielding the N-methylpyrazine-2-carbohydrazide deri-

˚

the centroid–centroid distance is 3.797 (2) A, the perpendi-

ꢂ

552 Gomes et al. C₁₃H₁₂N₄O and four analogues

Acta Cryst. (2013). C69, 549–555

organic compounds

Table 1

Table 3

Hydrogen-bond geometry (A, ) for (IIb).

ꢁ

Comparison of selected geometric parameters (^ꢁ).

˚

ꢁ is the dihedral angle between the pyrazine ring and the phenyl ring, ’₁and ’₂

are the torsion angles N21—C22—C2—N2 and N1—C1—C11—C12, respec-

tively, and ’₃is the angular deviation of atom C2 from the mean plane of the

pyrazine ring. In (Ib), the molecule sits on a mirror plane.

D—Hꢀ ꢀ ꢀA

C13—H13ꢀ ꢀ ꢀN21ⁱ

Symmetry code: (i) x ꢃ 1; y þ 1; z.

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

0.95

2.61

3.514 (8)

159

Compound R₁

ꢁ

’

1

’

3

2

(IIa)

(IIb)

H

o-OCH₃

(major)

o-OCH₃

(minor)

77.46 (6)

58.1 (3)

72.83 (14)

ꢃ128.9 (4)

175.16 (10) 6.77 (8)

168.73 (18) 3.2 (3)

Compound (IIb)

69.5 (3)

67.1 (6)

n/a

4.1 (3)

Crystal data

C₁₄H₁₄N₄O₂

M_r= 270.29

Triclinic, P1

a = 4.032 (5) A

b = 10.628 (15) A

˚

c = 15.034 (19) A

ꢂ = 94.08 (3)^ꢁ

ꢃ = 90.36 (3)^ꢁ

ꢄ = 92.07 (3)^ꢁ

V = 642.2 (15) A

Z = 2

(IIc)

(IId)

(IIe)

(Ib)

(Ic)

[p-CN]ꢀ2H₂O 55.43 (12) ꢃ135.8 (2)

169.8 (2)

178.7 (3)

3.5 (3)

0.0

4.06 (14)

6.3 (2)

4.59 (13)

0.0

3

˚

o-NO₂

p-NO₂

o-OCH₃

(p-CN

48.51(17

55.39 (9)

0.0

5.82 (7)

0.54 (5)

54.6 (4)

ꢃ62.3 (2)

0.0

ꢃ3.76 (18) 176.21 (17) 1.56 (9)

ꢃ12.72 (15) ꢃ169.90 (10) 1.49 (7)

˚

Mo Kꢂ radiation

ꢅ = 0.10 mm^ꢃ1

T = 100 K

0.18 ꢄ 0.13 ꢄ 0.12 mm

˚

(Id)

(o-NO₂

Data collection

vative as a colourless crystalline solid. Further recrystallizations of

the N-methylpyrazine-2-carbohydrazides were carried out from

appropriate solvents. A consistent recrystallization solvent, which

could provide suitable crystals for the X-ray study for the ﬁve deri-

vatives reported here, was not found. None of the solvents used was

specially dried.

Rigaku Saturn724+ diffractometer

Absorption correction: multi-scan

(CrystalClear-SM Expert;

Rigaku, 2011)

4990 measured reﬂections

2246 independent reﬂections

1859 reﬂections with I > 2ꢆ(I)

R_int= 0.033

T_min= 0.983, T_max= 0.988

Compound (IIa) (yield 54%, m.p. 391–393 K) was recrystallized

from EtOH for the X-ray analysis, (IIb) (yield 63%, 378–380 K) from

MeOCH₂CH₂OH, (IIc) (yield 73%, m.p. 383–384 K) from dimethyl

sulfoxide, (IId) (yield 66%, m.p. 424–425 K) from EtOH and (IIe)

(yield 58%, m.p. 458–460 K) from EtOH.

Reﬁnement

R[F²> 2ꢆ(F²)] = 0.055

wR(F²) = 0.159

S = 1.10

2246 reﬂections

185 parameters

6 restraints

H-atom paramete_ꢃrs₃constrained

˚

Áꢇ_max= 0.18 e A

ꢃ3

˚

Áꢇ_min= ꢃ0.26 e A

Compound (IIa)

Compound (IIc)

Crystal data

C₁₃H₁₂N₄O

M_r= 240.27

Triclinic, P1

a = 7.4961 (3) A

˚

b = 7.6923 (3) A

c = 10.8821 (7) A

ꢂ = 73.421 (5)^ꢁ

ꢃ = 84.844 (6)^ꢁ

ꢄ = 88.530 (6)^ꢁ

3

˚

V = 598.97 (5) A

Z = 2

3

˚

V = 1462.9 (3) A

Z = 4

C₁₄H₁₁N₅Oꢀ2H₂O

M_r= 301.31

Monoclinic, P2₁=c

˚

Mo Kꢂ radiation

ꢅ = 0.09 mm^ꢃ1

T = 120 K

0.56 ꢄ 0.43 ꢄ 0.23 mm

Mo Kꢂ radiation

ꢅ = 0.10 mm^ꢃ1

T = 120 K

0.56 ꢄ 0.23 ꢄ 0.08 mm

˚

a = 19.395 (3) A

b = 3.9517 (5) A

c = 23.270 (3) A

ꢃ = 124.890 (9)^ꢁ

˚

Data collection

Rigaku R-AXIS conversion

diffractometer

Absorption correction: multi-scan

(CrystalClear-SM Expert;

Rigaku, 2011)

7672 measured reﬂections

2712 independent reﬂections

2270 reﬂections with I > 2ꢆ(I)

R_int= 0.016

Rigaku R-AXIS conversion

diffractometer

Absorption correction: multi-scan

(CrystalClear-SM Expert;

Rigaku, 2011)

12564 measured reﬂections

3341 independent reﬂections

2189 reﬂections with I > 2ꢆ(I)

R_int= 0.053

T_min= 0.952, T_max= 0.980

T_min= 0.946, T_max= 0.992

Reﬁnement

R[F²> 2ꢆ(F²)] = 0.036

wR(F²) = 0.119

S = 1.17

164 parameters

H-atom paramete_ꢃrs₃constrained

Table 4

Hydrogen-bond geometry (A, ) for (IIc).

ꢁ

˚

Áꢇ_max= 0.31 e A

ꢃ3

˚

2712 reﬂections

Áꢇ_min= ꢃ0.21 e A

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

O1W—H1WBꢀ ꢀ ꢀN21

O2W—H2WAꢀ ꢀ ꢀO1W

O1W—H1WAꢀ ꢀ ꢀO2ⁱ

O2W—H2WBꢀ ꢀ ꢀO2Wⁱⁱ

C13—H13ꢀ ꢀ ꢀO1Wⁱⁱⁱ

C26—H26ꢀ ꢀ ꢀN141^iv

0.96

0.91

0.99

0.84

0.95

2.08

1.84

1.83

1.96

2.59

2.62

2.963 (2)

2.745 (3)

2.807 (2)

2.649 (3)

3.465 (3)

3.480 (3)

153

172

167

138

152

150

Table 2

Hydrogen-bond geometry (A, ) for (IIa).

ꢁ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

C25—H25ꢀ ꢀ ꢀO2ⁱ

0.95

2.59

3.1823 (16)

121

1

2

1

2

1

2

1

2

Symmetry codes: (i) x; y ꢃ 1; z; (ii) ꢃx þ 1; y ꢃ ; ꢃz þ ; (iii) x; ꢃy þ ; z þ ; (iv)

1

2

1

2

x; ꢃy þ ; z ꢃ .

Symmetry code: (i) x; y ꢃ 1; z.

ꢂ

Acta Cryst. (2013). C69, 549–555

Gomes et al.

C₁₃H₁₂N₄O and four analogues 553

organic compounds

Table 5

Hydrogen-bond geometry (A, ) for (IId).

Table 6

Hydrogen-bond geometry (A, ) for (IIe).

ꢁ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

C13—H13ꢀ ꢀ ꢀO122ⁱ

0.95

2.54

2.58

3.439 (5)

3.428 (4)

157

150

C15—H15ꢀ ꢀ ꢀO2ⁱ

0.95

2.42

2.36

3.325 (2)

3.290 (2)

159

166

C14—H14ꢀ ꢀ ꢀO2ⁱⁱ

C23—H23ꢀ ꢀ ꢀO2ⁱⁱ

1

2

1

2

1

2

Symmetry codes: (i) ꢃx þ 2; ꢃy þ 1; ꢃz; (ii) x þ 1; y; z ꢃ 1.

Symmetry codes: (i) x þ ; ꢃy þ ; z þ ; (ii) ꢃx þ 1; ꢃy þ 1; ꢃz þ 1.

Reﬁnement

In all ﬁve title compounds, H atoms were treated as riding, with

˚

C—H = 0.95 A and U_iso(H) = 1.2U_eq(C) for aromatic H atoms, or

˚

C—H = 0.98 A and U_iso(H) = 1.5U_eq(C) for methyl H atoms. In (IIc),

R[F²> 2ꢆ(F²)] = 0.063

wR(F²) = 0.248

S = 1.23

202 parameters

H-atom paramete_ꢃrs₃constrained

˚

Áꢇ_max= 0.40 e A

the water H atoms were located in a difference map and allowed to

ride at these positions, with U_iso(H) = 1.5U_eq(O). The positions of the

H atoms, methyl groups and water molecules were checked on

difference maps during the reﬁnement and after the reﬁnement was

complete. Initially, the disordered components of (IIb) were located

on a difference map. The disordered ring were found to be rotated by

approximately 180^ꢁwith respect to each other. In (IIb), both disor-

dered rings were restrained to be planar. Atoms N21, N24, N21A and

N24A were constrained to have the same anisotropic displacement

parameters, as were atoms C23, C26, C23A and C26A. The site-

occupation factor for the major component was 0.529 (9). No

constraints were appled to the bond lengths and angles.

ꢃ3

˚

3341 reﬂections

Áꢇ_min= ꢃ0.33 e A

Compound (IId)

Crystal data

3

˚

V = 1261.33 (11) A

Z = 4

C₁₃H₁₁N₅O₃

M_r= 285.27

Monoclinic, P2₁=c

Mo Kꢂ radiation

ꢅ = 0.11 mm^ꢃ1

T = 120 K

0.40 ꢄ 0.10 ꢄ 0.02 mm

˚

a = 3.7974 (2) A

˚

b = 33.3126 (17) A

˚

c = 10.0959 (5) A

ꢃ = 99.027 (2)^ꢁ

Data collection: CrystalClear-SM Expert (Rigaku, 2011) for (IIa),

(IIb), (IIc) and (IIe); COLLECT (Nonius, 2000) for (IId). Cell

reﬁnement: CrystalClear-SM Expert for (IIa), (IIb), (IIc) and (IIe);

SCALEPACK (Otwinowski & Minor, 1997) for (IId). Data reduc-

tion: CrystalClear-SM Expert for (IIa), (IIb), (IIc) and (IIe); DENZO

(Otwinowski & Minor, 1997) and SCALEPACK for (IId). For all

compounds, program(s) used to solve structure: SHELXS97 (Shel-

drick, 2008); program(s) used to reﬁne structure: OSCAIL (McArdle

et al., 2004) and SHELXL97 (Sheldrick, 2008); molecular graphics:

PLATON (Spek, 2009); software used to prepare material for

publication: OSCAIL and SHELXL97.

Data collection

Nonius KappaCCD area-detector

diffractometer

Absorption correction: multi-scan

(SADABS; Sheldrick, 1996)

T_min= 0.957, T_max= 0.998

11176 measured reﬂections

2168 independent reﬂections

1563 reﬂections with I > 2ꢆ(I)

R_int= 0.071

Reﬁnement

R[F²> 2ꢆ(F²)] = 0.080

wR(F²) = 0.196

S = 1.10

191 parameters

H-atom paramete_ꢃrs₃constrained

˚

Áꢇ_max= 0.32 e A

Áꢇ_min= ꢃ0.32 e A

ꢃ3

˚

2168 reﬂections

The authors thank the staff at the National Crystallographic

Service, University of Southampton, for the data collection,

and for help and advice (Coles & Gale, 2012).

Compound (IIe)

Supplementary data for this paper are available from the IUCr electronic

archives (Reference: SK3484). Services for accessing these data are

described at the back of the journal.

Crystal data

3

˚

V = 2628.7 (5) A

Z = 8

C₁₃H₁₁N₅O₃

M_r= 285.27

Monoclinic, C2=c

Mo Kꢂ radiation

ꢅ = 0.11 mm^ꢃ1

T = 120 K

0.42 ꢄ 0.24 ꢄ 0.16 mm

˚

a = 17.510 (2) A

b = 10.5421 (11) A

˚

References

˚

c = 14.9638 (14) A

ꢃ = 107.887 (8)^ꢁ

Allen, F . H . (2002). Acta Cryst. B 58 , 380–388.

Baddeley, T. C., Howie, R. A., Lima, C. H. da S., Kaiser, C. R., de Souza,

M. V . N ., James, L., Wardell, J. L. & Wardell, S. M. S. V . (2009). Z.

Kristallogr. 224 , 506–514.

Bernstein, J., Davis, R. E., Shimoni, I. & Chang, N.-L. (1995). Angew. Chem.

Int. Ed. Engl. 34 , 1555–1573.

Coles, S. J. & Gale, P . A . (2012). Chem. Sci. 3 , 683–689.

Howie, R. A., de Souza, M. V . N ., Wardell, S. M. S. V ., Wardell, J. L. & Tiekink,

E. R. T. (2010). Acta Cryst. E 66 , o178–o179.

Howie, R. A., Lima, C. H. S., Kaiser, C. R., de Souza, M. V . N ., Wardell, J. L. &

Wardell, S. M. S. V . (2010 a ). Z. Kristallogr. 225 , 19–28.

Howie, R. A., Lima, C. H. S., Kaiser, C. R., de Souza, M. V . N ., Wardell, J. L. &

Wardell, S. M. S. (2010 b ). Z. Kristallogr. 225 , 158–166.

Howie, R. A., Lima, C. H. S., Kaiser, C. R., de Souza, M. V . N ., Wardell, J. L. &

Wardell, S. M. S. (2010 c ). Z. Kristallogr. 225 , 349–358.

Lima, C. H. S., Henriques, M. G. M. O., Candea, A. L. P ., Lourenco, M. C. S.,

Bezerra, F . A . F . M ., Ferreira, M. L., Kaiser, C. R. & de Souza, M. V . N.

(2011). Med. Chem. 7 , 245–249.

Data collection

Rigaku R-AXIS conversion

diffractometer

Absorption correction: multi-scan

(CrystalClear-SM Expert;

Rigaku, 2011)

7284 measured reﬂections

3000 independent reﬂections

2610 reﬂections with I > 2ꢆ(I)

R_int= 0.042

T_min= 0.956, T_max= 0.983

Reﬁnement

R[F²> 2ꢆ(F²)] = 0.060

wR(F²) = 0.169

S = 1.08

191 parameters

H-atom paramete_ꢃrs₃constrained

˚

Áꢇ_max= 0.31 e A

Áꢇ_min= ꢃ0.26 e A

ꢃ3

˚

3000 reﬂections

ꢂ

554 Gomes et al. C₁₃H₁₂N₄O and four analogues

Acta Cryst. (2013). C69, 549–555

organic compounds

McArdle, P ., Gilligan, K., Cunningham, D., Dark, R. & Mahon, M. (2004).

CrystEngComm , 6 , 303–309.

Nonius (2000). COLLECT . Nonius B V , D elft, The Netherlands.

´

Orlewska, C., Foks, H., Sowinski, P ., Martynowski, D., Olczak, A. & Glowka,

M. L. (2001). Pol. J. Chem. 75 , 1237–1245.

Sheldrick, G. M. (2008). Acta Cryst. A 64 , 112–122.

Souza, M. V . N. d e (2013). Unpublished results.

Souza, M. V . N. d e, Lima, C. H. da S., Wardell, J. L., Wardell, S. M. S. V . &

Tiekink, E. R. T. (2011). Acta Cryst. E 67 , o1714–o1715.

Spek, A. L. (2009). Acta Cryst. D 65 , 148–155.

´

Szczesio, M., Olczak, A., Gołka, J., Gobis, K., Foks, H. & Głowka, M. L. (2011).

Acta Cryst. C 67 , o235–o240.

Vergara, F. M. F., Lima, C. H. da S., Henriques, M. das G. M. de O., Candea,

Otwinowski, Z. & Minor, W . (1997). Methods in Enzymology , Vol. 276,

Macromolecular Crystallography , Part A, edited by C. W . C arter Jr & R. M.

Sweet, pp. 307–326. New York: Academic Press.

Rigaku (2011). CrystalClear-SM Expert . Rigaku Corporation, T o kyo, Japan.

¨

Sheldrick, G. M. (1996). SADABS . University of Gottingen, Germany.

´

A. L. P ., Louren c ¸o, M. C. S., Ferreira, M. de L., Kaiser, C. R. & de Souza,

M. V . N. (2009). Eur. J. Med. Chem. 44 , 4954–4959.

ꢂ

Acta Cryst. (2013). C69, 549–555

Gomes et al.

C₁₃H₁₂N₄O and four analogues 555

supplementary materials

Acta Cryst. (2013). C69, 549-555 [doi:10.1107/S0108270113010056]

Five N′-benzylidene-N-methylpyrazine-2-carbohydrazides

Ligia R. Gomes, John Nicolson Low, Ana S. M. C. Rodrigues, James L. Wardell, Camillo H. da

Silva Lima and Marcus V. N. de Souza

(IIa) N′-Benzylidene-N-methylpyrazine-2-carbohydrazide

Crystal data

C₁₃H₁₂N₄O

Z = 2

M_r= 240.27

Triclinic, P1

F(000) = 252

D_x= 1.332 Mg m⁻³

Mo Kα radiation, λ = 0.71075 Å

Cell parameters from 6254 reflections

θ = 3.2–27.4°

Hall symbol: -P 1

a = 7.4961 (3) Å

b = 7.6923 (3) Å

c = 10.8821 (7) Å

α = 73.421 (5)°

β = 84.844 (6)°

γ = 88.530 (6)°

V = 598.97 (5) Å³

µ = 0.09 mm⁻¹

T = 120 K

Block, orange

0.56 × 0.43 × 0.23 mm

Data collection

Rigaku R-AXIS conversion

diffractometer

Radiation source: Sealed tube

Graphite monochromator

Detector resolution: 10.0000 pixels mm^-1

profile data from ω–scans

7672 measured reflections

2712 independent reflections

2270 reflections with I > 2σ(I)

R_int= 0.016

θ_max= 27.5°, θ_min= 3.2°

h = −9→9

k = −9→9

l = −14→14

Absorption correction: multi-scan

(CrystalClear-SM Expert; Rigaku, 2011)

T

_min= 0.952, T_max= 0.980

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.036

wR(F²) = 0.119

Secondary atom site location: difference Fourier

map

Hydrogen site location: inferred from

neighbouring sites

S = 1.17

2712 reflections

164 parameters

0 restraints

Primary atom site location: structure-invariant

direct methods

H-atom parameters constrained

w = 1/[σ²(F_o²) + (0.0656P)²+ 0.0688P]

where P = (F_o²+ 2F_c²)/3

(Δ/σ)_max< 0.001

Δρ_max= 0.31 e Å⁻³

Δρ_min= −0.21 e Å⁻³

Acta Cryst. (2013). C69, 549-555

sup-1

supplementary materials

Special details

Experimental. Compound (IIa): ¹H NMR (500 MHz, CDCl₃, δ, p.p.m.): 8.85 (, s, H₃), 8.69 (1H, s, H₅), 8.66 (1H, s, H₆),

7.81 (1H, N═CH), 7.39–7.33 (5H, m, phenyl), 3.62 (3H, s, NCH₃); ¹³C NMR (125 MHz, CDCl₃, δ, p.p.m.): 167.5, 150.2,

144.9, 144.7, 143.8, 141.1, 133.8, 130.2, 128.8, 127.3, 28.5; IR (KBr, ν, cm^-1): 1676 (C═O), 1606 (–N═C–CH₃). LC/MS:

m/z [M]^-: 240.

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 F²against 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

U_iso*/U_eq

O2

0.59462 (13)

0.71743 (12)

0.65947 (12)

0.51069 (14)

0.78603 (14)

0.75771 (14)

0.7479

0.82450 (11)

0.48356 (12)

0.65306 (12)

0.38869 (14)

0.37332 (14)

0.46307 (16)

0.5633

0.15785 (9)

0.42370 (9)

0.35592 (9)

0.21804 (10)

0.02828 (10)

0.53921 (10)

0.5740

0.0353 (2)

0.0222 (2)

0.0233 (2)

0.0300 (2)

0.0313 (3)

0.0239 (2)

0.029*

N1

N2

N21

N24

C1

H1

C2

0.62923 (15)

0.81848 (14)

0.87332 (16)

0.8700

0.67640 (15)

0.28776 (16)

0.27812 (17)

0.3838

0.23037 (11)

0.61799 (10)

0.73924 (11)

0.7680

0.0244 (2)

0.0237 (2)

0.0299 (3)

0.036*

C11

C12

H12

C13

H13

C14

H14

C15

H15

C16

H16

C22

C23

H23

C25

H25

C26

H26

C27

H27A

H27B

H27C

0.93248 (17)

0.9713

0.11570 (19)

0.1109

0.81768 (12)

0.8993

0.0338 (3)

0.041*

0.93520 (16)

0.9753

−0.03992 (18)

−0.1514

0.77750 (12)

0.8316

0.0321 (3)

0.039*

0.87901 (16)

0.8799

−0.03243 (17)

−0.1393

0.65759 (12)

0.6303

0.0295 (3)

0.035*

0.82177 (15)

0.7847

0.13007 (16)

0.1345

0.57781 (11)

0.4957

0.0256 (3)

0.031*

0.64153 (15)

0.77724 (16)

0.8673

0.51242 (15)

0.50456 (16)

0.5955

0.18023 (10)

0.08704 (11)

0.0639

0.0223 (2)

0.0277 (3)

0.033*

0.65355 (16)

0.6518

0.25194 (16)

0.1578

0.06350 (11)

0.0230

0.0267 (3)

0.032*

0.51892 (16)

0.4283

0.25938 (17)

0.1690

0.15723 (12)

0.1796

0.0302 (3)

0.036*

0.65016 (16)

0.6018

0.80741 (16)

0.9128

0.40887 (12)

0.3468

0.0285 (3)

0.043*

0.7705

0.8357

0.4262

0.043*

0.5719

0.7775

0.4892

0.043*

Acta Cryst. (2013). C69, 549-555

sup-2

supplementary materials

Atomic displacement parameters (Å²)

U¹¹

U²²

U³³

U¹²

U¹³

U²³

O2

0.0499 (6)

0.0209 (5)

0.0255 (5)

0.0280 (5)

0.0354 (6)

0.0231 (5)

0.0230 (5)

0.0189 (5)

0.0324 (6)

0.0345 (7)

0.0264 (6)

0.0259 (6)

0.0228 (5)

0.0248 (5)

0.0305 (6)

0.0313 (6)

0.0273 (6)

0.0307 (6)

0.0231 (5)

0.0222 (5)

0.0208 (5)

0.0304 (5)

0.0316 (6)

0.0262 (6)

0.0233 (6)

0.0298 (6)

0.0348 (7)

0.0422 (7)

0.0333 (7)

0.0288 (6)

0.0314 (6)

0.0220 (5)

0.0261 (6)

0.0255 (6)

0.0286 (6)

0.0254 (6)

0.0324 (5)

0.0234 (5)

0.0245 (5)

0.0331 (5)

0.0280 (5)

0.0248 (5)

0.0266 (6)

0.0229 (5)

0.0241 (6)

0.0230 (6)

0.0300 (6)

0.0333 (6)

0.0237 (5)

0.0199 (5)

0.0261 (6)

0.0254 (6)

0.0368 (6)

0.0331 (6)

0.0007 (4)

−0.0118 (4)

−0.0015 (3)

−0.0028 (4)

0.0022 (4)

−0.0049 (3)

−0.0066 (4)

−0.0079 (4)

−0.0124 (4)

−0.0111 (4)

−0.0061 (4)

−0.0084 (4)

−0.0105 (5)

−0.0052 (5)

0.0018 (5)

N1

−0.0011 (3)

−0.0013 (4)

−0.0066 (4)

−0.0056 (4)

−0.0027 (4)

−0.0028 (4)

−0.0031 (4)

−0.0039 (5)

−0.0044 (5)

−0.0015 (5)

−0.0016 (4)

−0.0009 (4)

−0.0076 (5)

−0.0007 (4)

−0.0074 (5)

−0.0008 (5)

N2

N21

N24

C1

0.0015 (4)

−0.0009 (4)

−0.0034 (4)

0.0002 (4)

C2

C11

C12

C13

C14

C15

C16

C22

C23

C25

C26

C27

−0.0024 (5)

−0.0060 (5)

−0.0025 (5)

−0.0005 (5)

−0.0022 (4)

−0.0067 (4)

0.0003 (4)

−0.0087 (5)

−0.0094 (5)

−0.0040 (4)

−0.0067 (5)

−0.0089 (4)

−0.0122 (5)

−0.0138 (5)

−0.0072 (4)

−0.0020 (5)

−0.0044 (5)

Geometric parameters (Å, º)

O2—C2

1.2233 (14)

C13—C14

1.3858 (19)

N1—C1

1.2841 (14)

1.3830 (13)

1.3652 (14)

1.4579 (13)

1.3376 (15)

1.3402 (15)

1.3341 (15)

1.3378 (15)

1.4628 (16)

0.9500

C13—H13

C14—C15

C14—H14

C15—C16

C15—H15

C16—H16

C22—C23

C23—H23

C25—C26

C25—H25

C26—H26

C27—H27A

C27—H27B

C27—H27C

0.9500

N1—N2

1.3921 (17)

0.9500

N2—C2

N2—C27

N21—C22

N21—C26

N24—C25

N24—C23

C1—C11

C1—H1

1.3858 (17)

0.9500

1.3833 (16)

0.9500

1.3811 (17)

0.9500

C2—C22

C11—C12

C11—C16

C12—C13

C12—H12

1.5084 (15)

1.3984 (15)

1.4008 (16)

1.3846 (18)

0.9500

0.9800

C1—N1—N2

C2—N2—N1

C2—N2—C27

N1—N2—C27

C22—N21—C26

C25—N24—C23

N1—C1—C11

N1—C1—H1

C11—C1—H1

117.51 (9)

116.86 (9)

120.23 (9)

122.54 (9)

115.12 (10)

115.75 (10)

121.02 (10)

119.5

C16—C15—C14

C16—C15—H15

C14—C15—H15

C15—C16—C11

C15—C16—H16

C11—C16—H16

N21—C22—C23

N21—C22—C2

C23—C22—C2

120.36 (11)

119.8

120.10 (10)

119.9

122.18 (10)

118.63 (10)

118.84 (10)

119.5

Acta Cryst. (2013). C69, 549-555

sup-3

supplementary materials

O2—C2—N2

122.49 (10)

119.42 (10)

118.09 (9)

119.02 (11)

118.09 (10)

122.89 (10)

120.51 (11)

119.7

N24—C23—C22

N24—C23—H23

C22—C23—H23

N24—C25—C26

N24—C25—H25

C26—C25—H25

N21—C26—C25

N21—C26—H26

C25—C26—H26

N2—C27—H27A

N2—C27—H27B

122.30 (10)

118.9

O2—C2—C22

N2—C2—C22

118.9

C12—C11—C16

C12—C11—C1

C16—C11—C1

C13—C12—C11

C13—C12—H12

C11—C12—H12

C12—C13—C14

C12—C13—H13

C14—C13—H13

C13—C14—C15

C13—C14—H14

C15—C14—H14

121.81 (10)

119.1

122.81 (10)

118.6

119.7

118.6

120.21 (11)

119.9

109.5

119.9

H27A—C27—H27B

N2—C27—H27C

109.5

119.79 (11)

120.1

H27A—C27—H27C

H27B—C27—H27C

120.1

C1—N1—N2—C2

175.51 (10)

2.55 (15)

C12—C11—C16—C15

C1—C11—C16—C15

C26—N21—C22—C23

C26—N21—C22—C2

O2—C2—C22—N21

N2—C2—C22—N21

O2—C2—C22—C23

N2—C2—C22—C23

C25—N24—C23—C22

N21—C22—C23—N24

C2—C22—C23—N24

C23—N24—C25—C26

C22—N21—C26—C25

N24—C25—C26—N21

−0.11 (17)

−179.28 (10)

−1.31 (16)

171.88 (10)

−107.86 (13)

72.83 (14)

65.56 (15)

−113.74 (12)

1.21 (17)

C1—N1—N2—C27

N2—N1—C1—C11

N1—N2—C2—O2

179.41 (9)

−172.75 (10)

0.38 (17)

C27—N2—C2—O2

N1—N2—C2—C22

C27—N2—C2—C22

N1—C1—C11—C12

N1—C1—C11—C16

C16—C11—C12—C13

C1—C11—C12—C13

C11—C12—C13—C14

C12—C13—C14—C15

C13—C14—C15—C16

C14—C15—C16—C11

6.53 (14)

179.66 (9)

175.16 (10)

−5.65 (17)

0.94 (17)

0.31 (18)

−179.85 (10)

−1.04 (19)

0.31 (19)

−172.87 (10)

−1.67 (17)

0.85 (17)

0.52 (18)

0.68 (19)

−0.62 (18)

Hydrogen-bond geometry (Å, º)

D—H···A

C25—H25···O2ⁱ

D—H

0.95

H···A

D···A

D—H···A

121

2.59

3.1823 (16)

Symmetry code: (i) x, y−1, z.

(IIb) N′-(2-Methoxybenzylidene)-N-methylpyrazine-2-carbohydrazide

Crystal data

C₁₄H₁₄N₄O₂

M_r= 270.29

Triclinic, P1

γ = 92.07 (3)°

V = 642.2 (15) Å³

Z = 2

Hall symbol: -P 1

a = 4.032 (5) Å

b = 10.628 (15) Å

c = 15.034 (19) Å

α = 94.08 (3)°

β = 90.36 (3)°

F(000) = 284

D_x= 1.394 Mg m⁻³

Mo Kα radiation, λ = 0.71075 Å

Cell parameters from 1623 reflections

θ = 2.4–31.2°

µ = 0.10 mm⁻¹

Acta Cryst. (2013). C69, 549-555

sup-4

supplementary materials

T = 100 K

0.18 × 0.13 × 0.12 mm

Block, brown

Data collection

Rigaku Saturn724+

diffractometer

Radiation source: Rotating anode

Confocal monochromator

Detector resolution: 28.5714 pixels mm^-1

profile data from ω–scans

4990 measured reflections

2246 independent reflections

1859 reflections with I > 2σ(I)

R_int= 0.033

θ_max= 25.0°, θ_min= 3.2°

h = −3→4

Absorption correction: multi-scan

(CrystalClear-SM Expert; Rigaku, 2011)

k = −12→12

l = −17→17

T

_min= 0.983, T_max= 0.988

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.055

wR(F²) = 0.159

Secondary atom site location: difference Fourier

map

Hydrogen site location: inferred from

neighbouring sites

S = 1.10

2246 reflections

185 parameters

6 restraints

Primary atom site location: structure-invariant

direct methods

H-atom parameters constrained

w = 1/[σ²(F_o²) + (0.0898P)²+ 0.0839P]

where P = (F_o²+ 2F_c²)/3

(Δ/σ)_max< 0.001

Δρ_max= 0.18 e Å⁻³

Δρ_min= −0.25 e Å⁻³

Special details

Experimental. Compound (IIb): ¹H NMR (500 MHz, CDCl₃, δ, p.p.m.): 8.85 (1H, s, H₃), 8.69 (1H, s, H₅), 8.64 (1H, s,

H₆), 8.23 (1H, s, N═CH), 7.35–7.30 (2H, m, H_4′and H_5′), 6.90–6.82 (2H, m, H_3′and H_6′), 3.88 (3H, s, OCH₃), 3.62 (3H, s,

NCH₃); ¹³C NMR (125 MHz, CDCl₃, δ, p.p.m.): 167.6, 158.2, 150.5, 145.1, 144.7, 143.9, 137.5, 131.6, 126.1, 122.4,

121.0, 111.1, 55.6, 28.8; IR (KBr, ν, cm^-1): 1680 (C═O), 1600 (–N═C–CH₃). LC/MS: m/z [M + H]⁺: 271.