Angelicain : Supramolecular structure generated by O-H…O, C-H…O and C-H…π hydrogen bonds, and π-π stacking interactions

Department of Applied Physics, M.B.S. college of Engineering and Technology* Natural Products Chemistry Division, Regional Research Laboratory, India**
○Sanjeev Goswami* Vivek K. Gupta** R.K. Thappa** S.G. Agarwal**

The compound angelicain (2-hydroxymethyl-5-hydroxy-10,11-dihydro-11(S)-(1-hydroxy-1-methylethyl)-2H-furo[2,3-g]-4H-1-benzopyran-4-one, C15H16O6) isolated from Angelica archangelica Linn. has been a seat of various biological activities and natural occurrence. The crystal structure of angelicain has been determined from X-ray diffraction data using direct methods. The compound crystallizes into monoclinic space group P21 with unit cell parameters : a=11.647(1)Å, b=7.268(1)Å, c=17.680(2)Å, b=105.54(2)o, Z = 4. The structure has been refined by full-matrix least-squares to a final R value of 0.038 for 2834 observed reflections. The structure contains two crystallographically independent molecules, A and B, in the asymmetric unit which are almost identical in geometry. The benzopyran moiety is planar and the furan ring has a C11-envelope conformation. In both the molecules, an intramolecular O-H…O hydrogen bond forms a pseudo-six membered ring. In the crystal structure, molecules A and B interact through O-H…O and p-p interactions, forming a dimer and further forming double chains along diagonal of the unit cell. The double chains are extended through C-H…O and C-H…p interactions forming a supramolecular structure.