I= CHEMICAL STUDIES ON THE CONSTITUENTS OF AZADIRACHTA INDICA A. JUSS.
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Title of Thesis
CHEMICAL STUDIES ON THE CONSTITUENTS OF AZADIRACHTA INDICA A. JUSS.

Author(s)
Ghiasuddin
Institute/University/Department Details
H.E.J. Research Institute of Chemistry/ University of Karachi
Session
1993
Subject
Chemistry
Number of Pages
249
Keywords (Extracted from title, table of contents and abstract of thesis)
azadirachta indica a. juss., epoxyazadiradione, azadiradione, triterpenoids, trinortriterpenoid, tetranortriterpenoids, oct anortriterpenoid, nonanortriterpenoids, steroidal glycosides

Abstract
The work embodied in the present thesis relates to the studies on the chemical constituents of Azadirachta indica and is presented in two parts. Part A describes the isolation and characterization of the chemical constituents of the fresh ripe fruit coats, ripe fruit kernels and the seed oil. Part B involves studies on the structure and activity relationship of new meliacin analogues prepared from epoxyazadiradione and azadiradione the two major constituents of the neem tree. A brief review of the biosynthesis of terpenoids with particular reference to the triterpenoids is also included.

PART A The introduction of part A provides a review of the earlier researches on the chemical constituents of A indica, their pharmacological and pesticidal properties, and a brief account of the present work. These studies have led to the isolation and structure elucidation of sixteen new and eight known triterpenoids,and two steroidal glycosides. Identification of four hydrocarbons has also been made through GC/MS.

NEW CONSTITUENTS

TRITERPENOIDS

I)Limocinol(1) II)Limocinone (5) III)Azadirol(12) IV)Naheedin (26)

TRINORTRITERPENOID

V)Limbonin (17)

TETRANORTRITERPENOIDS

VI)Limocin A (6) VII)Limocin B (7) VIII) Limocinin (8) IX)Azadironolide (15) X)Isoazadironolide (16) XI)Limbocinin (20) XII) Limbocidin (21) XIII) Mahmoodin (24)

OCT ANORTRITERPENOID

XIV) 5a-(13aMe)- Androsta-7a.-acetoxy-4,4,B-trimethyl-1, 14-dien-3, 16-dione (desfurano-azadiradione) (9)

NONANORTRITERPENOIDS

XV) 5a-(13aMe)-Androsta-7a.-acetoxy-17-oxa-4,4,B-trimethyl-1, 14-dien-3, 16-dione (10) XVI) 5a-Androsta-7a.-acetoxy-17-oxa-4,4,B-trimethyl-1, 14-dien-3, 16-dione (11 )

KNOWN CONSTITUENTS

I)Azadirone (III) II)Azadiradione (IV) III) Epoxyazadiradione (II) IV) Gedunin (V) V) Kulactone (4) VI) Nimbin(l) VII) Deacelylnimbin (VI) VIII) 17-Hydroxyazadiradione

STEROIDAL GLYCOSIDES

IX)Stigmasterol glycoside (22) X)Stigmasterol glycoside (23)

HYDROCARBONS

XI) Icosane XII) Docosane XIII) 2-Methyltricosane XIV) Docosene

PART B Hydrolysis of epoxyazadiradione and azadiradione, two major constituents of Azadirachta indica isolatable using simplified procedures (vide experimental) with ethanolic and methanolic potash respectively, led to new meliacin analogues listed below.

i)7-Deacetoxy-14-ethoxy-7cl, 15 β.-dihydroxy-14. 15-dihydroazadiradione(28) ii)7-Deacetoxy-7α-hydroxy-15-ethoxyazadiradione (30) iii)7-Deacetoxy-7α-hydroxy- 15-ethoxy-17-epiazadiradione (31) iv) 7-Deacetoxy-7α. 16-dihydroxy-15-ethoxy- Δ16-azadirone (32) v)7-Deacetoxy-7α.5β. 16-trihydroxy-14-ethoxy- 14. 15-dihydro-Δ16 -azadirone (34) vi)17-Epinimbocinol (35)

Extensive spectroscopic techniques such as IR, UV,CD, mass, 1H- and 13C-NMA (BB, DEPT), 2D-NMA (COSY-45, NOESY, Hetero COSY, HMQC and INADEQUATE), and chemical reactions were employed to elucidate the structure of all the isolated and synthetic compounds.

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S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
63.01 KB
2 1 General Introduction 5
308.63 KB
  1.1 Biosynthesis 11
3 2 Part-A Chemical studies on the constituents of azadriachta indica a. Juss 45
1095.77 KB
  2.1 Introduction 45
  2.2 Discussion of Present work and structural studies 85
  2.3 Experimental 135
4 3 Part-B New Meliancin analogues from epoxyazadiradione and azadiradione 197
342.24 KB
  3.1 Introduction 197
  3.2 Results and discussion 197
  3.3 Experimental 208
  3.4 References 225
5 3 Part-B New Meliancin analogues from epoxyazadiradione and azadiradione 197
342.24 KB
6 4 Appendix 245
58.14 KB
  4.1 List of Tables 245
  4.2 List of new substances 247
  4.3 List of Publications 249
  4.4 Vita 252