Synthesis of pharmacologically relevant arenes by [3+3] cyclizations and phytochemical investigation of pulicaria undulata [Elektronische Ressource] / Nasir Rasool

Synthesis of Pharmacologically Relevant Arenes by [3+3] Cyclizations
And Phytochemical Investigation of pulicaria undulata
I n a u g u r a l d i s s e r t a t i o n
zur
Erlangung des akademischen Grades
doctor rerum naturalium (Dr. rer. nat.)
an der Mathematisch-Naturwissenschaftlichen Fakultät
der
Universität Rostock
vorgelegt von
Nasir Rasool
geboren am 02-09-1977
In Chichawatni, Sahiwal, Pakistan
Rostock, 29-01-2008
urn:nbn:de:gbv:28-diss2008-0032-9
1Dekan :
1. Gutachter :
2. Gutachter :
Tag der Promotion :
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Contents
Acknowledgement
Abbreviations I
Summary II

PART A
General Introduction III
Chapter 1 IV
Chapter 2 V
Chapter 3 VI
Chapter 4 VII
Chapter 5 VIII
Chapter 6 IX
Chapter 7 X
Manuscript in preparation XI
X-ray crystal data
PART B
General Introduction XII
4 Chapter 8 XIII
PART C
General Introduction XIV
Chapter 9 XV
Chapter 10 XVI
Chapter11 XVII
Chapter 12 XVIII
Curriculum Vitae
Declaration/Erklärung
5 Acknowledgement
Start with name of Allah Almighty, Who bestowed me the shower of His blessings and
have given me courage to complete this tedious task.
I want to pay my humble gratitude to my supervisor Prof. Dr. Peter Langer, who has
given me a chance to work in his group and help me to surpass this barrier. Some special
words are due to my kind supervisor in Pakistan Dr Viqar-ud-Din Ahmad HEJ Research
Institute of Chemistry University of Karachi for his great help during my stay at
University of Karachi.
Many special thanks to Dr Martin Hein and Dr Michalik for his help in different
scientific problems and guidance in many special cases.
I am very thankful to Dr Zulfiqar Ali, Dr Athar Abbasi, Abid Rashid and Dr. Muhammad
Zubair for their co-operation and providing me friendly scientific environment at
University of Karachi.
Thanks are due to my lab fellows Abid Rashid, Andreas, Jope, Vahuni, Inam, Imran and
Satenik for providing me a good friendly environment in lab.
This acknowledgment can’t be complete without thanking Adeel, Yawer, Ibrar, Sven, Dr
Juma, Sher, Rasheed, Gerson, Steffi, Renske, Libnow,Büttner, Tung, Lau, Heffner, and
Majid,Asid
Many thanks are due to Abid, Adeel, Kamran, Hamad, Khurram, Mukhtar, Kashif, and
Azeem for their special company and enjoyable gossips at free time during my stay at
Rostock.
Thanks also go to the members of the technical sections (NMR, IR, MS and X-Ray etc)
University of Rostock and Leibniz Institute for Catalysis.
I want to highly appreciate Higher Educaion Commission (HEC) of Pakistan for
providing me funds for my research work here at University of Rostock.
At last but not least many thanks to my father, mother, sisters and brother in laws for
their forever moral help to complete this tedious task.
6 Abbreviations
Ar Aromatic
APT Attached Proton Test
ATCC American Type Culture Collection
nBuLi n-Butylithium
DEPT Distortionless Enhancement by Polarisation Transfer
EI Electronic Ionization
ESI Electrospray Ionization
EtOAc Ethylacetate
HRMS High Resolution Mass Spectroscopy
IR Infrared spectroscopy
LDA Lithium diisopropylamide
MS Mas Spectrometry
Ph Phenyl
NEt3 Triethylamine
NMR Nuclear Magnetic Resolution
HMQC Heteronuclear Multiple Quantum Coherence
HMBC uclMultiple Bond Correlation
COSY Correlated Spectroscopy
NOESY Nuclear Overhause and Exchange Spectroscopy
Me3SiOTf Trimethylsilyl trifluoro methanesulfonate
Me3SiCl imethylsilylchloride
mp. Melting point
RCM Ring Closing Metathesis
TBAI Tetrabutyl amonium iodie
TFA Trifluoroacetic acid
Tf2O ifluoromethanesulfonic anhydride
THF Tetrahydrofurane
TLC Thin Layer Chromatography
TMS Trimethylsilane
UV Ultraviolet spectroscop
7Summary
Dissertation can be summarized as following.
1. Chapter 1 deals with the cyclization of -ketosulfone, -ketonitrile and -
ketophosphonate dianions with 1, 1-diacetylcyclopropane. These reactions afford 1-
hydroxyspiro[5.2]cyclooct-4-en-3-ones which were transformed, by reaction with
tetrabutylammonium halides, into functionalized phenols.
2. Chapter 2 includes the cyclization of the dianions of diethyl 2-oxopropylphosphonate
and of acetone with 1, 1-diacylopropanes. These reactions afforded
hydroxyspiro[5.2]cyclooctenones which were transformed, by homo-Michael reactions
with tetrabutylammonium halides, into various functionalized phenols or their dimmers.
3. In chapter 3 we have described the chemo- and regioselective synthesis of -bromo-3-
ketosulfones, -bromo-3-ketonitriles and various functionalized 2-(-
bromoalkyl)benzofurans by application of a ′ring-closing/ring-opening′ strategy. The
cyclization of 3-ketosulfone and 3-ketonitrile dianions with 1-bromo-2-chloroethane or
1,4-dibromobut-2-ene afforded functionalized 2-alkylidenetetrahydrofurans which were
subsequently cleaved by reaction with boron tribromide or boron trichloride.
4. In chapter 4 we have reported sterically encumbered diaryl ethers which are prepared
based on formal [3+3] cyclizations of novel 4-aryloxy-1,3-bis(trimethylsilyloxy)-1,3-
dienes.
5. In chapter 5 we have studied fuctionalized 1-azaxanthones (5-oxo-5H-[1]-
benzopyrano[2,3-b]pyridines) which were prepared by TMSOTf-mediated reaction of
1,3-bis(trimethylsilyloxy)-1,3-butadienes with cyanochromones and subsequent base-
mediated domino retro-Michael / nitrile-addition / heterocyclization reactions.
6. In chapter 6 we have reported sterically encumbered biaryls which are regioselectively
prepared based on formal [3+3] cyclizations of novel 4-aryl-1,3-bis(trimethylsilyloxy)-
1,3-dienes.
7. Chapter 7 deals with the regioselective synthesis of functionalized
thiophenoxybenzoates by domino [3+3] cycllization / homo Michael reactions of 1-
trimethylsilyloxy-3-thiophenoxy-1, 3-butadienes with 1,1-diacylcyclopropanes.
8. In chapter 8 we studied the synthesis of various tetraarylthiophenes based on Suzuki
reactions of tetrabromothiophene.
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