Related literature   {#sec1}
====================

For the biological activity of flavone derivatives, see: Thomas *et al.* (2013[@bb6]); Kumar *et al.* (2014[@bb3]); Lee *et al.* (2014[@bb4]). For further synthetic details, see: Vasanthi *et al.* (2014[@bb7]).

Experimental   {#sec2}
==============

Crystal data   {#sec2.1}
--------------

C~20~H~16~O~3~*M* *~r~* = 304.33Monoclinic,*a* = 7.3612 (3) Å*b* = 17.8540 (9) Å*c* = 11.9465 (6) Åβ = 105.697 (2)°*V* = 1511.54 (12) Å^3^*Z* = 4Mo *K*α radiationμ = 0.09 mm^−1^*T* = 293 K0.30 × 0.25 × 0.20 mm

Data collection   {#sec2.2}
-----------------

Bruker Kappa APEXII CCD diffractometerAbsorption correction: multi-scan (*SADABS*; Bruker, 2004[@bb1]) *T* ~min~ = 0.974, *T* ~max~ = 0.98233755 measured reflections3548 independent reflections2297 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.035

Refinement   {#sec2.3}
------------

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.048*wR*(*F* ^2^) = 0.171*S* = 1.003548 reflections209 parametersH-atom parameters constrainedΔρ~max~ = 0.35 e Å^−3^Δρ~min~ = −0.21 e Å^−3^

 {#d5e356}

Data collection: *APEX2* (Bruker, 2004[@bb1]); cell refinement: *SAINT* (Bruker, 2004[@bb1]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb5]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb5]); molecular graphics: *ORTEP-3 for Windows* (Farrugia, 2012[@bb2]); software used to prepare material for publication: *SHELXL97*.

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

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: [10.1107/S2056989015007082/hb7401sup1.cif](http://dx.doi.org/10.1107/S2056989015007082/hb7401sup1.cif)

Structure factors: contains datablock(s) I. DOI: [10.1107/S2056989015007082/hb7401Isup2.hkl](http://dx.doi.org/10.1107/S2056989015007082/hb7401Isup2.hkl)

###### 

Click here for additional data file.

Supporting information file. DOI: [10.1107/S2056989015007082/hb7401Isup3.cml](http://dx.doi.org/10.1107/S2056989015007082/hb7401Isup3.cml)

###### 

Click here for additional data file.

. DOI: [10.1107/S2056989015007082/hb7401fig1.tif](http://dx.doi.org/10.1107/S2056989015007082/hb7401fig1.tif)

The mol­ecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level.

###### 

Click here for additional data file.

. DOI: [10.1107/S2056989015007082/hb7401fig2.tif](http://dx.doi.org/10.1107/S2056989015007082/hb7401fig2.tif)

The packing of the mol­ecules in the crystal structure. The dashed lines indicate the hydrogen bonds.

CCDC reference: [1058707](http://scripts.iucr.org/cgi-bin/cr.cgi?rm=csd&csdid=1058707)

Additional supporting information: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?hb7401&file=hb7401sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?hb7401sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?hb7401&checkcif=yes)

Supporting information for this paper is available from the IUCr electronic archives (Reference: [HB7401](http://scripts.iucr.org/cgi-bin/sendsup?hb7401)).

The authors thank SAIF (IIT Madras) for collecting the intensity data.

S1. Synthesis and crystallization {#d1e22}
=================================

The procedure (Vasanthi *et al.*, 2014) adopted in the synthesis of the compound 3-(4-meth­oxy­phenyl)-2,3-di­hydro-1H-benzo(f)chromen-1-one is represented here. In a 250 ml round-bottomed flask 2-hy­droxy-1-aceto­naphthone (0.05 mol) and 4-meth­oxy­oxybenzaldehyde (0.05mol) were placed to which about 100 ml of absolute alcohol was added and stirred at room temperature for a time span of 5 minutes. Then about 10 ml of 40% sodium hydroxide solution was added and the mixture was stirred for 6 hours. On adding ice cold water a precipitate was generated which was filtered, washed with sufficient qu­antity of distilled water and dried. The crude product was recrystallized twice from chloro­form (yield = 86%).

S2. Refinement {#d1e39}
==============

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were positioned geometrically and treated as riding on their parent atoms, with C---H distance of 0.93-0.97Å with Uiso(H)= 1.5 Ueq(c-methyl) and Uiso(H)= 1.2Ueq(C) for other H atom.

Figures
=======

![The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level.](e-71-0o332-fig1){#Fap1}

![The packing of the molecules in the crystal structure. The dashed lines indicate the hydrogen bonds.](e-71-0o332-fig2){#Fap2}

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

  ------------------------- ---------------------------------------
  C~20~H~16~O~3~            *F*(000) = 640
  *M~r~* = 304.33           *D*~x~ = 1.337 Mg m^−3^
  Monoclinic, *P*2~1~/*n*   Mo *K*α radiation, λ = 0.71073 Å
  Hall symbol: -p 2yn       Cell parameters from 3548 reflections
  *a* = 7.3612 (3) Å        θ = 2.1--27.7°
  *b* = 17.8540 (9) Å       µ = 0.09 mm^−1^
  *c* = 11.9465 (6) Å       *T* = 293 K
  β = 105.697 (2)°          Block, pale yellow
  *V* = 1511.54 (12) Å^3^   0.30 × 0.25 × 0.20 mm
  *Z* = 4                   
  ------------------------- ---------------------------------------

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

  ------------------------------------------------------------ --------------------------------------
  Bruker Kappa APEXII CCD diffractometer                       3548 independent reflections
  Radiation source: fine-focus sealed tube                     2297 reflections with *I* \> 2σ(*I*)
  Graphite monochromator                                       *R*~int~ = 0.035
  ω and φ scan                                                 θ~max~ = 27.7°, θ~min~ = 2.1°
  Absorption correction: multi-scan (*SADABS*; Bruker, 2004)   *h* = −9→9
  *T*~min~ = 0.974, *T*~max~ = 0.982                           *k* = −23→23
  33755 measured reflections                                   *l* = −15→15
  ------------------------------------------------------------ --------------------------------------

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

  ------------------------------------- -------------------------------------------------------------------------------------------------
  Refinement on *F*^2^                  Primary atom site location: structure-invariant direct methods
  Least-squares matrix: full            Secondary atom site location: difference Fourier map
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.048   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.171                  H-atom parameters constrained
  *S* = 1.00                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0866*P*)^2^ + 0.5483*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  3548 reflections                      (Δ/σ)~max~ \< 0.001
  209 parameters                        Δρ~max~ = 0.35 e Å^−3^
  0 restraints                          Δρ~min~ = −0.21 e Å^−3^
  ------------------------------------- -------------------------------------------------------------------------------------------------

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

  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  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 *F*^2^ against ALL reflections. The weighted *R*-factor *wR* and goodness of fit *S* are based on *F*^2^, conventional *R*-factors *R* are based on *F*, with *F* set to zero for negative *F*^2^. The threshold expression of *F*^2^ \> σ(*F*^2^) is used only for calculating *R*-factors(gt) *etc*. and is not relevant to the choice of reflections for refinement. *R*-factors based on *F*^2^ 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 (Å^2^) {#tablewrapcoords}
==================================================================================================

  ------ -------------- --------------- -------------- -------------------- --
         *x*            *y*             *z*            *U*~iso~\*/*U*~eq~   
  C1     0.8210 (3)     0.31670 (11)    0.50857 (17)   0.0479 (5)           
  H1     0.7380         0.3483          0.4572         0.057\*              
  C2     0.9984 (3)     0.34116 (12)    0.5627 (2)     0.0569 (6)           
  H2     1.0348         0.3890          0.5468         0.068\*              
  C3     1.1261 (3)     0.29601 (14)    0.6411 (2)     0.0615 (6)           
  H3     1.2457         0.3139          0.6785         0.074\*              
  C4     1.0749 (3)     0.22571 (13)    0.66264 (19)   0.0552 (5)           
  H4     1.1603         0.1956          0.7152         0.066\*              
  C5     0.8940 (3)     0.19745 (11)    0.60665 (16)   0.0442 (4)           
  C6     0.7616 (2)     0.24405 (10)    0.52940 (15)   0.0398 (4)           
  C7     0.5772 (2)     0.21474 (10)    0.47367 (14)   0.0380 (4)           
  C8     0.5436 (2)     0.13995 (10)    0.48896 (15)   0.0404 (4)           
  C9     0.6770 (3)     0.09415 (11)    0.56488 (18)   0.0480 (5)           
  H9     0.6500         0.0440          0.5741         0.058\*              
  C10    0.8442 (3)     0.12317 (11)    0.62434 (17)   0.0494 (5)           
  H10    0.9285         0.0935          0.6782         0.059\*              
  C11    0.4166 (3)     0.26181 (11)    0.41137 (16)   0.0444 (4)           
  C12    0.2355 (3)     0.22029 (11)    0.3582 (2)     0.0534 (5)           
  H12A   0.1573         0.2214          0.4118         0.064\*              
  H12B   0.1675         0.2456          0.2875         0.064\*              
  C13    0.2685 (3)     0.14097 (11)    0.33062 (18)   0.0478 (5)           
  H13    0.3405         0.1408          0.2726         0.057\*              
  C14    0.0947 (3)     0.09419 (11)    0.28505 (18)   0.0461 (5)           
  C15    −0.0210 (3)    0.07528 (12)    0.35425 (18)   0.0537 (5)           
  H15    0.0094         0.0918          0.4309         0.064\*              
  C16    −0.1816 (3)    0.03216 (12)    0.31180 (18)   0.0514 (5)           
  H16    −0.2587        0.0201          0.3593         0.062\*              
  C17    −0.2257 (3)    0.00744 (10)    0.19866 (17)   0.0451 (5)           
  C18    0.0466 (3)     0.06940 (12)    0.17210 (18)   0.0511 (5)           
  H18    0.1226         0.0818          0.1241         0.061\*              
  C19    −0.1111 (3)    0.02680 (12)    0.12893 (18)   0.0521 (5)           
  H19    −0.1413        0.0107          0.0520         0.062\*              
  C20    −0.5019 (3)    −0.05604 (15)   0.2142 (3)     0.0741 (7)           
  H20A   −0.4325        −0.0834         0.2814         0.111\*              
  H20B   −0.6009        −0.0870         0.1684         0.111\*              
  H20C   −0.5558        −0.0120         0.2386         0.111\*              
  O1     0.38066 (18)   0.10428 (7)     0.43445 (12)   0.0496 (4)           
  O2     0.4204 (2)     0.32953 (8)     0.40683 (15)   0.0635 (5)           
  O3     −0.3787 (2)    −0.03475 (9)    0.14670 (14)   0.0619 (4)           
  ------ -------------- --------------- -------------- -------------------- --

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

  ----- ------------- ------------- ------------- -------------- ------------- --------------
        *U*^11^       *U*^22^       *U*^33^       *U*^12^        *U*^13^       *U*^23^
  C1    0.0537 (11)   0.0423 (11)   0.0461 (11)   −0.0051 (8)    0.0107 (9)    −0.0012 (8)
  C2    0.0593 (13)   0.0490 (12)   0.0598 (13)   −0.0147 (10)   0.0116 (10)   −0.0031 (10)
  C3    0.0483 (11)   0.0647 (14)   0.0659 (14)   −0.0137 (10)   0.0059 (10)   −0.0081 (11)
  C4    0.0475 (11)   0.0594 (13)   0.0524 (12)   0.0030 (9)     0.0026 (9)    −0.0006 (10)
  C5    0.0453 (10)   0.0439 (10)   0.0416 (10)   0.0005 (8)     0.0083 (8)    −0.0015 (8)
  C6    0.0460 (10)   0.0382 (9)    0.0351 (9)    −0.0008 (7)    0.0110 (7)    −0.0026 (7)
  C7    0.0438 (9)    0.0356 (9)    0.0336 (9)    0.0003 (7)     0.0089 (7)    −0.0012 (7)
  C8    0.0424 (10)   0.0377 (10)   0.0404 (10)   −0.0021 (7)    0.0103 (7)    0.0002 (8)
  C9    0.0535 (11)   0.0367 (10)   0.0514 (11)   0.0010 (8)     0.0099 (9)    0.0069 (8)
  C10   0.0523 (11)   0.0460 (11)   0.0451 (11)   0.0071 (9)     0.0047 (9)    0.0066 (9)
  C11   0.0499 (10)   0.0365 (10)   0.0443 (10)   0.0010 (8)     0.0084 (8)    0.0005 (8)
  C12   0.0491 (11)   0.0445 (11)   0.0597 (13)   0.0020 (8)     0.0029 (9)    0.0016 (9)
  C13   0.0472 (11)   0.0463 (11)   0.0473 (11)   −0.0005 (8)    0.0084 (8)    0.0003 (9)
  C14   0.0424 (10)   0.0417 (10)   0.0520 (11)   0.0004 (8)     0.0091 (8)    −0.0005 (8)
  C15   0.0587 (12)   0.0587 (13)   0.0419 (11)   −0.0037 (10)   0.0104 (9)    −0.0084 (9)
  C16   0.0515 (11)   0.0538 (12)   0.0512 (12)   −0.0021 (9)    0.0178 (9)    −0.0032 (9)
  C17   0.0414 (10)   0.0399 (10)   0.0520 (11)   0.0015 (8)     0.0093 (8)    −0.0043 (8)
  C18   0.0495 (11)   0.0545 (12)   0.0518 (12)   −0.0038 (9)    0.0182 (9)    −0.0047 (9)
  C19   0.0536 (11)   0.0571 (13)   0.0461 (11)   −0.0038 (9)    0.0146 (9)    −0.0103 (9)
  C20   0.0521 (13)   0.0760 (17)   0.098 (2)     −0.0161 (12)   0.0263 (13)   −0.0099 (15)
  O1    0.0474 (8)    0.0395 (7)    0.0554 (8)    −0.0048 (6)    0.0028 (6)    0.0053 (6)
  O2    0.0619 (10)   0.0377 (8)    0.0802 (11)   0.0039 (6)     0.0008 (8)    0.0028 (7)
  O3    0.0538 (9)    0.0633 (10)   0.0681 (10)   −0.0171 (7)    0.0159 (7)    −0.0162 (8)
  ----- ------------- ------------- ------------- -------------- ------------- --------------

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

  -------------------- -------------- ----------------------- --------------
  C1---C2              1.362 (3)      C12---C13               1.489 (3)
  C1---C6              1.413 (3)      C12---H12A              0.9700
  C1---H1              0.9300         C12---H12B              0.9700
  C2---C3              1.391 (3)      C13---O1                1.448 (2)
  C2---H2              0.9300         C13---C14               1.501 (3)
  C3---C4              1.355 (3)      C13---H13               0.9800
  C3---H3              0.9300         C14---C18               1.372 (3)
  C4---C5              1.412 (3)      C14---C15               1.380 (3)
  C4---H4              0.9300         C15---C16               1.387 (3)
  C5---C10             1.407 (3)      C15---H15               0.9300
  C5---C6              1.417 (3)      C16---C17               1.375 (3)
  C6---C7              1.439 (2)      C16---H16               0.9300
  C7---C8              1.379 (2)      C17---O3                1.357 (2)
  C7---C11             1.477 (2)      C17---C19               1.381 (3)
  C8---O1              1.359 (2)      C18---C19               1.366 (3)
  C8---C9              1.405 (3)      C18---H18               0.9300
  C9---C10             1.347 (3)      C19---H19               0.9300
  C9---H9              0.9300         C20---O3                1.419 (3)
  C10---H10            0.9300         C20---H20A              0.9600
  C11---O2             1.211 (2)      C20---H20B              0.9600
  C11---C12            1.507 (3)      C20---H20C              0.9600
                                                              
  C2---C1---C6         120.91 (19)    C13---C12---H12B        109.1
  C2---C1---H1         119.5          C11---C12---H12B        109.1
  C6---C1---H1         119.5          H12A---C12---H12B       107.8
  C1---C2---C3         121.3 (2)      O1---C13---C12          109.26 (16)
  C1---C2---H2         119.3          O1---C13---C14          106.95 (15)
  C3---C2---H2         119.3          C12---C13---C14         115.83 (16)
  C4---C3---C2         119.52 (19)    O1---C13---H13          108.2
  C4---C3---H3         120.2          C12---C13---H13         108.2
  C2---C3---H3         120.2          C14---C13---H13         108.2
  C3---C4---C5         121.08 (19)    C18---C14---C15         118.26 (18)
  C3---C4---H4         119.5          C18---C14---C13         120.25 (18)
  C5---C4---H4         119.5          C15---C14---C13         121.49 (18)
  C10---C5---C4        121.09 (18)    C14---C15---C16         121.34 (19)
  C10---C5---C6        119.34 (17)    C14---C15---H15         119.3
  C4---C5---C6         119.56 (18)    C16---C15---H15         119.3
  C1---C6---C5         117.55 (17)    C17---C16---C15         119.26 (19)
  C1---C6---C7         123.44 (17)    C17---C16---H16         120.4
  C5---C6---C7         118.98 (16)    C15---C16---H16         120.4
  C8---C7---C6         118.11 (16)    O3---C17---C16          125.00 (19)
  C8---C7---C11        118.04 (16)    O3---C17---C19          115.47 (18)
  C6---C7---C11        123.53 (16)    C16---C17---C19         119.52 (18)
  O1---C8---C7         123.85 (16)    C19---C18---C14         121.16 (19)
  O1---C8---C9         114.13 (16)    C19---C18---H18         119.4
  C7---C8---C9         122.01 (17)    C14---C18---H18         119.4
  C10---C9---C8        119.73 (18)    C18---C19---C17         120.47 (19)
  C10---C9---H9        120.1          C18---C19---H19         119.8
  C8---C9---H9         120.1          C17---C19---H19         119.8
  C9---C10---C5        121.42 (17)    O3---C20---H20A         109.5
  C9---C10---H10       119.3          O3---C20---H20B         109.5
  C5---C10---H10       119.3          H20A---C20---H20B       109.5
  O2---C11---C7        124.46 (17)    O3---C20---H20C         109.5
  O2---C11---C12       120.04 (17)    H20A---C20---H20C       109.5
  C7---C11---C12       115.37 (16)    H20B---C20---H20C       109.5
  C13---C12---C11      112.50 (16)    C8---O1---C13           115.06 (14)
  C13---C12---H12A     109.1          C17---O3---C20          117.87 (18)
  C11---C12---H12A     109.1                                  
                                                              
  C6---C1---C2---C3    −0.8 (3)       C8---C7---C11---C12     −7.0 (2)
  C1---C2---C3---C4    1.3 (4)        C6---C7---C11---C12     179.61 (17)
  C2---C3---C4---C5    0.1 (4)        O2---C11---C12---C13    157.9 (2)
  C3---C4---C5---C10   176.6 (2)      C7---C11---C12---C13    −26.1 (2)
  C3---C4---C5---C6    −2.0 (3)       C11---C12---C13---O1    55.1 (2)
  C2---C1---C6---C5    −1.1 (3)       C11---C12---C13---C14   175.91 (17)
  C2---C1---C6---C7    −179.08 (19)   O1---C13---C14---C18    −126.0 (2)
  C10---C5---C6---C1   −176.18 (18)   C12---C13---C14---C18   112.0 (2)
  C4---C5---C6---C1    2.5 (3)        O1---C13---C14---C15    54.4 (2)
  C10---C5---C6---C7   1.9 (3)        C12---C13---C14---C15   −67.7 (3)
  C4---C5---C6---C7    −179.48 (17)   C18---C14---C15---C16   0.2 (3)
  C1---C6---C7---C8    171.55 (18)    C13---C14---C15---C16   179.89 (18)
  C5---C6---C7---C8    −6.4 (3)       C14---C15---C16---C17   0.4 (3)
  C1---C6---C7---C11   −15.1 (3)      C15---C16---C17---O3    −179.74 (19)
  C5---C6---C7---C11   167.02 (17)    C15---C16---C17---C19   −0.9 (3)
  C6---C7---C8---O1    −175.03 (16)   C15---C14---C18---C19   −0.3 (3)
  C11---C7---C8---O1   11.2 (3)       C13---C14---C18---C19   −179.97 (19)
  C6---C7---C8---C9    5.9 (3)        C14---C18---C19---C17   −0.2 (3)
  C11---C7---C8---C9   −167.86 (18)   O3---C17---C19---C18    179.78 (18)
  O1---C8---C9---C10   −179.81 (18)   C16---C17---C19---C18   0.9 (3)
  C7---C8---C9---C10   −0.7 (3)       C7---C8---O1---C13      20.1 (3)
  C8---C9---C10---C5   −4.2 (3)       C9---C8---O1---C13      −160.76 (17)
  C4---C5---C10---C9   −175.1 (2)     C12---C13---O1---C8     −52.9 (2)
  C6---C5---C10---C9   3.5 (3)        C14---C13---O1---C8     −178.94 (15)
  C8---C7---C11---O2   168.8 (2)      C16---C17---O3---C20    −0.9 (3)
  C6---C7---C11---O2   −4.6 (3)       C19---C17---O3---C20    −179.7 (2)
  -------------------- -------------- ----------------------- --------------
