HETEROCYCLES, Vol. 60, No. 4, 2003
947
HETEROCYCLES, Vol. 60, No. 4, 2003, pp. 947 - 951
Received, 18th December, 2002, Accepted, 7th February, 2003, Published online, 17th February, 2003
C-ALKYLATED COUMARIN AND COUMARIN GLYCOSIDE
FROM DAPHNE OLEOIDES
*a)
Abdul Malik, Muhammad Riaza), Erum Akbara) Muhammad Rafiquea)
,
,
and Nighat Afzab)
a)H.E.J. Research Institute of Chemistry, University of Karachi, Karachi-75270,
Pakistan
b)Pharmaceutical and Fine Chemical Division, PCSIR Karachi Complex,
Karachi, Pakistan
Abstract- New C-alkylated coumarin (1) and coumarin glucoside (2) have been
isolated from the roots of Daphne oleoides. The structures of 1 and 2 were
established through spectroscopic and chemical studies.
The genus Daphne (Thymelaeceae) is a principal source of coumarins. It comprises of many species,
represented in Pakistan by Daphne oleoides. It is a small shrub, frequently found in the northern areas of
Pakistan. The roots of this species are purgative, its bark and leaves are given in cutaneous infections,
whereas infusion of leaves is given in gonorrhea.1 Previously triterpenoids,2 lignan glycosides,3
biscoumarins,4 and tricoumarins,5 have been reported from this species. Reinvestigations on the coumarin
constituents of the roots of this plant have now resulted in the isolation and characterization of new C-
alkylated coumarin (1) and coumarin glycoside (2), respectively.
Compound (1) was obtained as colorless amorphous powder. The molecular formula was established as
C14H16O7 on the basis of ion peak at m/z 296.2732 (calcd 296.2726 for C14H16O7) in HREIMS. It gave
characteristic blue spot on silica gel plates under UV light (365 nm) and the UV absorption bands at 204,
258 and 320 nm suggested the coumarin skeleton.6 The IR spectrum of 1 exhibited the absorption at
3490, 1718, 1605, 1562 and 1250 cm-1, which indicated the presence of hydroxyl, lactone, aromatic and
methoxyl functionalities.
The 13C-NMR spectrum revealed the presence of fourteen carbon atoms, which were assigned by DEPT
spectrum as one alcoholic methylene, five methine, two methyl, and six quaternary carbons. It included
the characteristic signal for α,β-unsaturated carbonyl carbon of coumarins at δ 160.3 and 144.3 and three
1
oxygenated aromatic carbons at 161.2, 158.9 and 156.3, respectively. The H-NMR spectrum howed
olefinic protons ad δ 7.78 and 6.39 (d, J = 9.5 Hz), aromatic proton at 6.91 and two methoxyl groups at δ
3. 79. The presence of trihydroxypropanoid moiety could be inferred by the signals of two vicinal protons
at δ 5.58 (d, J = 8.3 Hz), 4.44 (dt, J = 8.3, 4.0 Hz) corresponding to the oxygenated methines and two
further protons of a hydroxymethylene at δ 4.59 (m).