Chemical context   {#sec1}
==================

For the last several decades, Schiff bases have remained an important and popular area of research for the scientific community due to their simple synthesis, versatility and extensive range of applications (Cozzi, 2004[@bb5]; Chen *et al.*, 2008[@bb4]). A number of carbonyl compounds and amines have been utilized for the synthesis of Schiff bases (Zheng *et al.*, 2009[@bb18]; Hussain *et al.*, 2014[@bb9]). However, there are only a few reports where de­hydro­acetic acid (DHA) has been used for the preparation of Schiff bases for various applications (Liu *et al.*, 1991[@bb10]; Luo *et al.*, 1995[@bb11]). In some cases, DHA-based Schiff bases are used for the synthesis of metal complexes, leading to their utilization in various biomedical applications due to their anti­fungal, anti­bacterial, anti­malarial and anti­cancer activities (Chan & Wong, 1995[@bb3]; Erkkila *et al.*, 1999[@bb6]; Ganjali *et al.*, 2007[@bb7]; Gupta & Sutar, 2008[@bb8]). In general, the compounds are formed *via* a condensation product of hydrazine and the respective aldehyde or ketone in a 1:1 molar ratio. Structurally, a Schiff base (also known as an imine or azomethine) is a nitro­gen analogue of an aldehyde or ketone in which the carbonyl group (C=O) has been replaced by an imine or azomethine group.

The reaction between *p*-nitro­phenyl­hydrazine and de­hydro­acetic acid (DHA) in a 1:1 molar ratio in distilled ethanol afforded the title compound within 4 h. We report herein on its characterization by FT--IR, ^1^H and ^13^C NMR and UV--Vis spectroscopic and single-crystal X-ray diffraction techniques.

Structural commentary   {#sec2}
=======================

The mol­ecular structure of the title compound is shown in Fig. 1[▸](#fig1){ref-type="fig"}. The dihedral angle between the pyran (O2/C9--C13) and benzene (C1--C6) rings is 12.9 (1)°. The approximate planarity of the entire mol­ecule maybe influenced by an intra­molecular O1---H1⋯N3 hydrogen bond, which forms an *S*(6) ring.

Supra­molecular features   {#sec3}
==========================

The crystal packing features strong N2---H2⋯O3^i^ hydrogen bonds between the NH group and the O~carbon­yl~ atom of the DHA moiety of symmetry-related mol­ecules, creating infinite chains along \[101\] (see Table 1[▸](#table1){ref-type="table"} for symmetry code). This O~carbon­yl~ atom is also weakly hydrogen bonded to a symmetry-related hydrogen atom (C5--H5⋯O3^i^), forming a bifurcated N---H,C---H⋯O hydrogen bond (Fig. 2[▸](#fig2){ref-type="fig"}). In a similar fashion, the O2 atom of the pyran ring forms a weak hydrogen bond to the methyl hydrogen of an adjacent mol­ecule (C7---H7*A*⋯O2^i^). The chains are arranged in a herringbone pattern in the three-dimensional structure (Fig. 3[▸](#fig3){ref-type="fig"}).

Hirshfeld surface analysis   {#sec4}
============================

The Hirshfeld surface was mapped with *d* ~norm~ to visualize the inter­molecular inter­actions and 2-D fingerprint plots were generated using *Crystal Explorer* (Wolff *et al.*, 2012[@bb17]) (Fig. 4[▸](#fig4){ref-type="fig"}).

Spectroscopic and TG analysis   {#sec5}
===============================

The FT--IR spectrum of the title compound shows a characteristic peak at 1687 cm^−1^ which has been consigned for *ν* ~C=N~, whereas the broad signal at 3280 cm^−1^ (*ν* ~O--H~) indicates the presence of a phenolic group. The ^1^H NMR spectrum display a singlet at *δ* 15.23 ppm, which clearly indicates the dominance of the *enol* form of the title compound over the *keto* form. The absorption spectra for HMNP was recorded in C~2~H~5~OH, and λ~max~ was observed at 394 nm, which is ascribed to the π→π\* or *n*→π\* transition of the C=O or C=N group. To probe the thermal stability of HMNP, thermogravimetric analysis (TGA) was undertaken and it was found that HMNP is stable to 513 K.

Synthesis and crystallization   {#sec6}
===============================

*Materials and methods: p*-Nitro­phenyl­hydrazine and de­hydro­acetic acid were of analytical grade and purchased from Spectrochem and Merck (India), respectively, and used as received. However, analytical grade solvents were purified wherever necessary as per as the standard literature method (Perrin *et al.*, 1980[@bb12]). The FT--IR spectra were recorded with a Perkin--Elmer FTIR--2000 spectrometer. The NMR spectroscopic measurements were carried out with a JEOL AL-400 MHz spectrometer. The thermogravimetric analysis (TGA) measurement was performed on an SDT Q600 (V20.9 Build 20) instrument (Artisan Technology Group, Champaign, IL) under N~2~ atmosphere with a heating rate of 10 K min^−1^. The absorbance spectrum was recorded on a JASCO V-530 UV/vis Spectrophotometer.

*Synthesis of (E)-4-hy­droxy-6-methyl-3-(1-(2-(4-nitro­phen­yl) hydrazone) eth­yl) 2-H-pyran-2-one* (**HMNP**):

HMNP was synthesized by the reaction of DHA (0.56g, 0.003 mol) with *para*-nitro­phenyl­hydrazine (0.45g, 0.003 mol) in distilled ethanol (15 mL) under reflux condition at 353 K for 3 h (Fig. 5[▸](#fig5){ref-type="fig"}). The progress of the reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the reaction mixture was cooled to room temperature and the yellow crystalline precipitate was filtrated off and washed with cold ethanol and dried \[yield: 0.728g (80%)\]. Crystals suitable for single crystal X-ray analysis were obtained by the slow evaporation of a THF solution of HMNP for 7--8 d.

FT--IR (selected peaks): 3280 (O--H), 3088 (N--H), 1687 (C=O), 1646 (C=N) cm^−1^. Absorption spectrum \[*λ* ~max~, nm, C~2~H~5~OH (∊, *M* ^−1^ cm^−1^)\]: 394 (150), 274 (*sh*, 525). ^1^H NMR (CDCl~3~, 400 MHz): *δ* (ppm): 15.23 (*s*, 1H, H~e~), 8.23--8.21 (*d*, 2H, H~a)~, 7.34 (1*s*, 1H, H~c~), 6.94--6.93 (*d*, 2H, H~b~), 5.93 (*s*, 1H, H~f~), 2.67 (1*s*, 3H, H~g~), 2.25 (1*s*, 3H, H~d~). ^13^C NMR (DMSO-*d~6~*, 100 MHz): *δ* 176.4 (C~8~), 167.1 (C~12~), 163.1 (C~10~), 150.2 (C~7~), 139.5 (C~4~), 125.8 (C~1~), 111.3 (C~2~), 103.3 (C~3~), 96.4 (C~9~), 79.1 (C~5~), 78.7 (C~11~), 78.3 (C~6~).

Refinement   {#sec7}
============

Crystal data, data collection and structure refinement details are summarized in Table 2[▸](#table2){ref-type="table"}. The NH and OH hydrogen atoms were located in a difference-Fourier map and freely refined. The C-bound H atoms were included in calculated positions and treated as riding atoms: C---H = 0.93--0.96 Å, O---H= 0.82 Å with *U* ~iso~(H) = 1.2*U* ~eq~(C) and *U* ~iso~(H) = 1.5*U* ~eq~(C~meth­yl~). The crystal studied was a non-merohedral twin with the refined ratio of the twin components being 0.3720 (19):0.6280 (19) using twin matrix (0 0) (0 0) (0.265 0 ).

Supplementary Material
======================

Crystal structure: contains datablock(s) I. DOI: [10.1107/S2056989017000639/lh5834sup1.cif](https://doi.org/10.1107/S2056989017000639/lh5834sup1.cif)

Structure factors: contains datablock(s) I. DOI: [10.1107/S2056989017000639/lh5834Isup2.hkl](https://doi.org/10.1107/S2056989017000639/lh5834Isup2.hkl)

###### 

Click here for additional data file.

Supporting information file. DOI: [10.1107/S2056989017000639/lh5834Isup3.cdx](https://doi.org/10.1107/S2056989017000639/lh5834Isup3.cdx)

###### 

Click here for additional data file.

Supporting information file. DOI: [10.1107/S2056989017000639/lh5834Isup4.cml](https://doi.org/10.1107/S2056989017000639/lh5834Isup4.cml)

CCDC reference: [1515036](http://scripts.iucr.org/cgi-bin/cr.cgi?rm=csd&csdid=1515036)

Additional supporting information: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?lh5834&file=lh5834sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?lh5834sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?lh5834&checkcif=yes)

The authors thank the School of Chemistry, Hyderabad Central University, Hyderabad 500 046, India, for the single-crystal X-ray data collection. RK thanks the University Grant Commission (UGC), New Delhi, India, for providing financial support in the form of a UGC--BSR research start-up grant \[F. 30--86/2014(BSR)\].

Crystal data {#tablewrapcrystaldatalong}
============

  ------------------------- ---------------------------------------
  C~14~H~13~N~3~O~5~        *F*(000) = 632
  *M~r~* = 303.27           *D*~x~ = 1.460 Mg m^−3^
  Monoclinic, *P*2~1~/*n*   Mo *K*α radiation, λ = 0.71073 Å
  *a* = 6.9633 (3) Å        Cell parameters from 9944 reflections
  *b* = 19.5008 (9) Å       θ = 2.3--30.3°
  *c* = 10.2031 (5) Å       µ = 0.11 mm^−1^
  β = 95.196 (2)°           *T* = 297 K
  *V* = 1379.78 (11) Å^3^   Block, colourless
  *Z* = 4                   0.16 × 0.13 × 0.10 mm
  ------------------------- ---------------------------------------

Data collection {#tablewrapdatacollectionlong}
===============

  ---------------------------------------------------------------- --------------------------------------
  Bruker APEXII CCD diffractometer                                 2302 reflections with *I* \> 2σ(*I*)
  φ and ω scans                                                    *R*~int~ = 0.028
  Absorption correction: multi-scan (*TWINABS*; Sheldrick, 2012)   θ~max~ = 26.0°, θ~min~ = 2.3°
                                                                   *h* = −8→8
  2696 measured reflections                                        *k* = 0→24
  2696 independent reflections                                     *l* = 0→12
  ---------------------------------------------------------------- --------------------------------------

Refinement {#tablewraprefinementdatalong}
==========

  ------------------------------------- -------------------------------------------------------------------------------------------------
  Refinement on *F*^2^                  1 restraint
  Least-squares matrix: full            Hydrogen site location: mixed
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.043   H atoms treated by a mixture of independent and constrained refinement
  *wR*(*F*^2^) = 0.121                  *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0606*P*)^2^ + 0.3029*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  *S* = 1.08                            (Δ/σ)~max~ \< 0.001
  2696 reflections                      Δρ~max~ = 0.18 e Å^−3^
  208 parameters                        Δρ~min~ = −0.20 e Å^−3^
  ------------------------------------- -------------------------------------------------------------------------------------------------

Special details {#specialdetails}
===============

  -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
  Refinement. Refined as a 2-component twin.
  -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å^2^) {#tablewrapcoords}
==================================================================================================

  ------ ------------- -------------- -------------- -------------------- --
         *x*           *y*            *z*            *U*~iso~\*/*U*~eq~   
  O1     0.3744 (2)    0.45226 (6)    0.80648 (13)   0.0531 (4)           
  H1     0.344 (4)     0.4379 (12)    0.7235 (19)    0.080\*              
  O2     0.6082 (2)    0.28918 (6)    1.00744 (12)   0.0469 (3)           
  O3     0.6119 (3)    0.22490 (6)    0.83226 (13)   0.0663 (5)           
  O4     0.0188 (3)    0.67218 (8)    0.2507 (2)     0.0812 (6)           
  O5     −0.0004 (3)   0.61297 (9)    0.07175 (19)   0.0865 (6)           
  N1     0.0349 (3)    0.61838 (9)    0.1917 (2)     0.0611 (5)           
  N2     0.3120 (2)    0.38498 (7)    0.46572 (14)   0.0398 (4)           
  H2     0.268 (3)     0.3474 (11)    0.432 (2)      0.048\*              
  N3     0.3581 (2)    0.38475 (6)    0.60024 (13)   0.0347 (3)           
  C1     0.1015 (3)    0.55793 (9)    0.2667 (2)     0.0451 (5)           
  C2     0.1693 (3)    0.56440 (9)    0.3967 (2)     0.0444 (4)           
  H2A    0.167336      0.606928       0.437835       0.053\*              
  C3     0.2406 (3)    0.50781 (8)    0.46645 (17)   0.0391 (4)           
  H3     0.289862      0.512366       0.553813       0.047\*              
  C4     0.2383 (2)    0.44367 (8)    0.40531 (16)   0.0337 (4)           
  C5     0.1636 (3)    0.43827 (9)    0.27327 (18)   0.0462 (5)           
  H5     0.158976      0.395663       0.232158       0.055\*              
  C6     0.0978 (3)    0.49483 (10)   0.20466 (19)   0.0517 (5)           
  H6     0.050752      0.491001       0.116717       0.062\*              
  C7     0.5379 (3)    0.27794 (9)    0.57620 (17)   0.0454 (5)           
  H7A    0.454884      0.238623       0.575635       0.068\*              
  H7B    0.664122      0.265763       0.614883       0.068\*              
  H7C    0.546326      0.293406       0.487576       0.068\*              
  C8     0.4574 (2)    0.33419 (8)    0.65505 (16)   0.0332 (4)           
  C9     0.5723 (3)    0.28148 (8)    0.87201 (16)   0.0410 (4)           
  C10    0.4942 (2)    0.33851 (8)    0.79792 (15)   0.0329 (4)           
  C11    0.4516 (3)    0.39848 (8)    0.86652 (17)   0.0389 (4)           
  C12    0.4968 (3)    0.40211 (10)   1.00539 (19)   0.0491 (5)           
  H12    0.472308      0.442214       1.050290       0.059\*              
  C13    0.5736 (3)    0.34866 (9)    1.07078 (17)   0.0451 (4)           
  C14    0.6316 (4)    0.34367 (13)   1.21487 (19)   0.0689 (7)           
  H14A   0.564868      0.306098       1.251241       0.103\*              
  H14B   0.599050      0.385539       1.257136       0.103\*              
  H14C   0.768155      0.336166       1.228953       0.103\*              
  ------ ------------- -------------- -------------- -------------------- --

Atomic displacement parameters (Å^2^) {#tablewrapadps}
=====================================

  ----- ------------- ------------- ------------- -------------- -------------- --------------
        *U*^11^       *U*^22^       *U*^33^       *U*^12^        *U*^13^        *U*^23^
  O1    0.0792 (10)   0.0393 (7)    0.0400 (7)    0.0220 (7)     0.0012 (7)     0.0015 (6)
  O2    0.0651 (8)    0.0416 (7)    0.0322 (6)    0.0067 (6)     −0.0064 (6)    0.0044 (5)
  O3    0.1158 (14)   0.0320 (6)    0.0454 (8)    0.0182 (8)     −0.0238 (8)    −0.0018 (6)
  O4    0.0772 (12)   0.0448 (9)    0.1196 (16)   0.0129 (8)     −0.0011 (11)   0.0242 (9)
  O5    0.0958 (14)   0.0791 (12)   0.0806 (13)   0.0013 (10)    −0.0138 (11)   0.0484 (10)
  N1    0.0438 (9)    0.0498 (10)   0.0889 (15)   0.0011 (8)     0.0009 (9)     0.0340 (10)
  N2    0.0555 (9)    0.0297 (7)    0.0317 (8)    −0.0015 (7)    −0.0101 (6)    0.0025 (6)
  N3    0.0398 (8)    0.0327 (7)    0.0303 (7)    −0.0018 (6)    −0.0039 (6)    0.0047 (5)
  C1    0.0382 (9)    0.0397 (9)    0.0563 (12)   −0.0006 (8)    −0.0016 (8)    0.0210 (8)
  C2    0.0436 (10)   0.0312 (8)    0.0587 (12)   −0.0023 (8)    0.0059 (9)     0.0048 (8)
  C3    0.0427 (9)    0.0347 (8)    0.0389 (10)   −0.0036 (7)    −0.0017 (8)    0.0025 (7)
  C4    0.0349 (8)    0.0308 (8)    0.0345 (9)    −0.0030 (6)    −0.0025 (7)    0.0068 (6)
  C5    0.0610 (11)   0.0383 (9)    0.0371 (10)   −0.0013 (9)    −0.0068 (9)    0.0042 (7)
  C6    0.0611 (12)   0.0516 (11)   0.0396 (10)   −0.0018 (10)   −0.0102 (9)    0.0134 (8)
  C7    0.0601 (12)   0.0401 (9)    0.0342 (9)    0.0088 (9)     −0.0052 (8)    −0.0031 (7)
  C8    0.0364 (8)    0.0277 (7)    0.0344 (8)    −0.0031 (6)    −0.0026 (7)    0.0014 (6)
  C9    0.0547 (11)   0.0331 (8)    0.0329 (9)    0.0011 (8)     −0.0083 (8)    0.0020 (7)
  C10   0.0368 (8)    0.0301 (8)    0.0307 (8)    −0.0006 (6)    −0.0024 (7)    0.0023 (6)
  C11   0.0458 (10)   0.0337 (8)    0.0371 (9)    0.0051 (7)     0.0028 (7)     0.0024 (7)
  C12   0.0670 (13)   0.0450 (10)   0.0354 (9)    0.0098 (9)     0.0053 (9)     −0.0048 (8)
  C13   0.0550 (11)   0.0494 (10)   0.0304 (9)    0.0041 (9)     0.0020 (8)     −0.0008 (8)
  C14   0.0965 (18)   0.0774 (15)   0.0312 (10)   0.0156 (14)    −0.0026 (11)   −0.0018 (10)
  ----- ------------- ------------- ------------- -------------- -------------- --------------

Geometric parameters (Å, º) {#tablewrapgeomlong}
===========================

  -------------------- -------------- ----------------------- --------------
  O1---C11             1.305 (2)      C4---C5                 1.403 (2)
  O1---H1              0.899 (17)     C5---C6                 1.363 (2)
  O2---C13             1.360 (2)      C5---H5                 0.9300
  O2---C9              1.390 (2)      C6---H6                 0.9300
  O3---C9              1.216 (2)      C7---C8                 1.499 (2)
  O4---N1              1.220 (2)      C7---H7A                0.9600
  O5---N1              1.231 (3)      C7---H7B                0.9600
  N1---C1              1.458 (2)      C7---H7C                0.9600
  N2---C4              1.377 (2)      C8---C10                1.460 (2)
  N2---N3              1.3809 (18)    C9---C10                1.424 (2)
  N2---H2              0.85 (2)       C10---C11               1.408 (2)
  N3---C8              1.301 (2)      C11---C12               1.425 (3)
  C1---C2              1.373 (3)      C12---C13               1.324 (3)
  C1---C6              1.383 (3)      C12---H12               0.9300
  C2---C3              1.381 (2)      C13---C14               1.492 (2)
  C2---H2A             0.9300         C14---H14A              0.9600
  C3---C4              1.397 (2)      C14---H14B              0.9600
  C3---H3              0.9300         C14---H14C              0.9600
                                                              
  C11---O1---H1        104.1 (16)     H7A---C7---H7B          109.5
  C13---O2---C9        122.74 (13)    C8---C7---H7C           109.5
  O4---N1---O5         123.05 (18)    H7A---C7---H7C          109.5
  O4---N1---C1         118.4 (2)      H7B---C7---H7C          109.5
  O5---N1---C1         118.5 (2)      N3---C8---C10           115.09 (14)
  C4---N2---N3         119.41 (13)    N3---C8---C7            122.27 (14)
  C4---N2---H2         115.4 (14)     C10---C8---C7           122.54 (14)
  N3---N2---H2         116.0 (14)     O3---C9---O2            113.81 (14)
  C8---N3---N2         119.75 (14)    O3---C9---C10           128.22 (15)
  C2---C1---C6         120.96 (16)    O2---C9---C10           117.97 (14)
  C2---C1---N1         119.85 (18)    C11---C10---C9          118.16 (15)
  C6---C1---N1         119.18 (18)    C11---C10---C8          121.23 (14)
  C1---C2---C3         120.03 (16)    C9---C10---C8           120.60 (14)
  C1---C2---H2A        120.0          O1---C11---C10          122.02 (16)
  C3---C2---H2A        120.0          O1---C11---C12          118.12 (15)
  C2---C3---C4         119.77 (16)    C10---C11---C12         119.85 (15)
  C2---C3---H3         120.1          C13---C12---C11         120.32 (17)
  C4---C3---H3         120.1          C13---C12---H12         119.8
  N2---C4---C3         123.76 (14)    C11---C12---H12         119.8
  N2---C4---C5         117.25 (15)    C12---C13---O2          120.85 (16)
  C3---C4---C5         118.95 (15)    C12---C13---C14         127.50 (18)
  C6---C5---C4         120.68 (17)    O2---C13---C14          111.65 (16)
  C6---C5---H5         119.7          C13---C14---H14A        109.5
  C4---C5---H5         119.7          C13---C14---H14B        109.5
  C5---C6---C1         119.57 (17)    H14A---C14---H14B       109.5
  C5---C6---H6         120.2          C13---C14---H14C        109.5
  C1---C6---H6         120.2          H14A---C14---H14C       109.5
  C8---C7---H7A        109.5          H14B---C14---H14C       109.5
  C8---C7---H7B        109.5                                  
                                                              
  C4---N2---N3---C8    −168.31 (16)   C13---O2---C9---C10     −0.6 (3)
  O4---N1---C1---C2    −9.0 (3)       O3---C9---C10---C11     177.1 (2)
  O5---N1---C1---C2    170.29 (19)    O2---C9---C10---C11     −2.2 (3)
  O4---N1---C1---C6    172.0 (2)      O3---C9---C10---C8      −2.0 (3)
  O5---N1---C1---C6    −8.7 (3)       O2---C9---C10---C8      178.60 (16)
  C6---C1---C2---C3    1.9 (3)        N3---C8---C10---C11     −9.8 (2)
  N1---C1---C2---C3    −177.08 (17)   C7---C8---C10---C11     166.71 (17)
  C1---C2---C3---C4    −1.8 (3)       N3---C8---C10---C9      169.40 (16)
  N3---N2---C4---C3    12.9 (3)       C7---C8---C10---C9      −14.1 (3)
  N3---N2---C4---C5    −169.53 (16)   C9---C10---C11---O1     −177.92 (17)
  C2---C3---C4---N2    177.75 (17)    C8---C10---C11---O1     1.3 (3)
  C2---C3---C4---C5    0.2 (3)        C9---C10---C11---C12    3.5 (3)
  N2---C4---C5---C6    −176.40 (19)   C8---C10---C11---C12    −177.33 (18)
  C3---C4---C5---C6    1.3 (3)        O1---C11---C12---C13    179.38 (19)
  C4---C5---C6---C1    −1.2 (3)       C10---C11---C12---C13   −2.0 (3)
  C2---C1---C6---C5    −0.4 (3)       C11---C12---C13---O2    −0.9 (3)
  N1---C1---C6---C5    178.59 (18)    C11---C12---C13---C14   179.3 (2)
  N2---N3---C8---C10   −178.73 (15)   C9---O2---C13---C12     2.3 (3)
  N2---N3---C8---C7    4.8 (2)        C9---O2---C13---C14     −177.92 (19)
  C13---O2---C9---O3   179.91 (19)                            
  -------------------- -------------- ----------------------- --------------

Hydrogen-bond geometry (Å, º) {#tablewraphbondslong}
=============================

  -------------------- ---------- ---------- ------------- ---------------
  *D*---H···*A*        *D*---H    H···*A*    *D*···*A*     *D*---H···*A*
  O1---H1···N3         0.90 (2)   1.64 (2)   2.4760 (18)   154 (2)
  N2---H2···O3^i^      0.85 (2)   2.00 (2)   2.8361 (19)   165.2 (19)
  C5---H5···O3^i^      0.93       2.60       3.264 (2)     129
  C7---H7*A*···O2^i^   0.96       2.51       3.283 (2)     138
  -------------------- ---------- ---------- ------------- ---------------

Symmetry code: (i) *x*−1/2, −*y*+1/2, *z*−1/2.

![The mol­ecular structure of the title compound, showing the atom-naming scheme. The displacement ellipsoids are shown at the 50% probability level.](e-73-00223-fig1){#fig1}

![A chain parallel to \[101\] formed by the inter­molecular hydrogen bonding (dashed lines) between the N---H group and carbonyl O atom of the DHA moiety. Weak C---H⋯O hydrogen bonds are also shown as dashed lines.](e-73-00223-fig2){#fig2}

![The crystal packing showing the herringbone arrangement of HMNP, viewed along the *a* axis. C-bound H atoms have been omitted for clarity. Hydrogen bonds are shown as dashed lines.](e-73-00223-fig3){#fig3}

![(*a*) Hirshfeld surfaces representation for HMNP mapped with *d* ~norm~. (*b*)--(*d*) Fingerprint plots of HMNP resolved into different inter­molecular inter­actions showing the percentages of contacts contributing to the total Hirshfeld surface.](e-73-00223-fig4){#fig4}

![Synthetic route for the organic ligand HMNP.](e-73-00223-fig5){#fig5}

###### Hydrogen-bond geometry (Å, °)

  *D*---H⋯*A*        *D*---H    H⋯*A*      *D*⋯*A*       *D*---H⋯*A*
  ------------------ ---------- ---------- ------------- -------------
  O1---H1⋯N3         0.90 (2)   1.64 (2)   2.4760 (18)   154 (2)
  N2---H2⋯O3^i^      0.85 (2)   2.00 (2)   2.8361 (19)   165.2 (19)
  C5---H5⋯O3^i^      0.93       2.60       3.264 (2)     129
  C7---H7*A*⋯O2^i^   0.96       2.51       3.283 (2)     138

Symmetry code: (i) .

###### Experimental details

  -------------------------------------------------------------------------- ------------------------------------------------------------------------
  Crystal data                                                               
  Chemical formula                                                           C~14~H~13~N~3~O~5~
  *M* ~r~                                                                    303.27
  Crystal system, space group                                                Monoclinic, *P*2~1~/*n*
  Temperature (K)                                                            297
  *a*, *b*, *c* (Å)                                                          6.9633 (3), 19.5008 (9), 10.2031 (5)
  β (°)                                                                      95.196 (2)
  *V* (Å^3^)                                                                 1379.78 (11)
  *Z*                                                                        4
  Radiation type                                                             Mo *K*α
  μ (mm^−1^)                                                                 0.11
  Crystal size (mm)                                                          0.16 × 0.13 × 0.10
                                                                             
  Data collection                                                            
  Diffractometer                                                             Bruker APEXII CCD
  Absorption correction                                                      Multi-scan (*TWINABS*; Sheldrick, 2012[@bb14])
  No. of measured, independent and observed \[*I* \> 2σ(*I*)\] reflections   2696, 2696, 2302
  *R* ~int~                                                                  0.028
  (sin θ/λ)~max~ (Å^−1^)                                                     0.617
                                                                             
  Refinement                                                                 
  *R*\[*F* ^2^ \> 2σ(*F* ^2^)\], *wR*(*F* ^2^), *S*                          0.043, 0.121, 1.08
  No. of reflections                                                         2696
  No. of parameters                                                          208
  No. of restraints                                                          1
  H-atom treatment                                                           H atoms treated by a mixture of independent and constrained refinement
  Δρ~max~, Δρ~min~ (e Å^−3^)                                                 0.18, −0.20
  -------------------------------------------------------------------------- ------------------------------------------------------------------------

Computer programs: *APEX2* and *SAINT* (Bruker, 2010[@bb2]), *SHELXS2013* (Sheldrick 2008[@bb13]), *SHELXL2016* (Sheldrick, 2015[@bb15]), *X-SEED* (Barbour 2001[@bb1]) and *publCIF* (Westrip 2010[@bb16]).
