This dissertation describes the phytochemical investigations on two medicinally important plants namely withania somnifera and fumaria flabellata. A separate section on X-ray diffraction studies o some natural and synthetic products is also included in this thesis.
Studies on chemical constituents of withania somnifera have led to isolation of a new withanolide, somilactone (101) along with the four known withanolides, (-)-sominolide (102), (-)sominohe (103), mindabeolide-1(104), and withanolide-R (105).
A new isoquinoline alkaloid flabelline (106) has been isolated form fumaria flabellata, of Turkish origin. In addition eleven known alkaloids corydaldine(107), Oxyhydrastine (108), fumaritine (109), protopine (110), fumariline (111), tetrahydropalmatine (112), N-feruloy1tyramine (113), juziphine (114), (+)-bicuclline (115), (-)corlumine (116), and O-methy1fumarophcine (117) have also been isolated for the first time form this source.
Structures of these new and known natural product were determined on the basis of extensive spectroscopic studies including one-, two-and inverse two-dimensional NMR experiments (such as COSY, HOHAHA, HMQC, HMBC etc.).
The second half of this thesis comprises on three dimensional structural determination of natural and synthetic products by X-ray diffraction analysis. Structure of a novel triterpene perovskone (130) isolated from perovuskia abrotanoides, two antifungal diterpenoidal non-alkaloids 8-acety1herophllisine (131), and panicutine(132), and a non-alkaloid 3-hydroxy-2-methy1-4H-pyran-4-one (133) isolated form delphinium denudatum, structures of three triterpenoidal compounds azadiraone (134), azadirone (135) and kulactone(136) isolated form azadirachta indica, were determined. Three new synthetic products 3,6-nahydro-4-O-[p-toluneesulfoney1] –D-glucal (137). 2(R),3(R), 2,4-dihydroxy-3-tosy1-terahydrofuran (138) and 7-[α-(hydroxyl)-m-nitrobenzy1]-8-quinolinol (139) have also been determined by X-Ray diffraction techniques.