Yeni bis(4'-morfolinofenoksi)etilen glikol podandların sentezi ve antimikrobiyal aktivitelerinin incelenmesi
The synthesis of new bis(4'-morpholinophenoxy)ethylene glycol podands and investigation of their antimicrobial activity
Yazar: EGEMEN TORLAKLI
Danışman: DOÇ. DR. GÖNÜL YAPAR
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Kimya Ana Bilim Dalı / Kimya Bilim Dalı
Derece: Yüksek Lisans, 2018
Konu: Kimya = Chemistry

Özet:
Eşsiz iyon bağlama yeteneklerinden dolayı sentetik iyonofor makro moleküller geniş ölçüde sentezlenmiş ve karakterizasyonları yapılmıştır. C. J. Pedersen tarafından keşfedildiklerinden bu yana makro halkalı eterler hakkında birçok çalışma yayınlanmıştır. Bu tür moleküllerin katyon bağlama davranışları hem molekülün yapısı ve stereo kimyası hem de makro halkada taşıdıkları oksijen ve azot gibi donör atomlarının elektronegatif özellik göstermesi ile ilişkilidir. Yapılarında etilenoksi üniteleri taşıyan ve Pedersen tarafından taç eter (crown ether) olarak adlandırılan makro halkalı bu bileşikler koronand olarak isimlendirilirken bunların açık zincir şeklinde olanları podand olarak isimlendirilir. Bu tür moleküller sadece katyonları bağlamakla kalmazlar, bir arada bulunan birkaç katyon içerisinden sadece bir tanesini seçimli olarak diğerlerinden ayırabilirler. Makro halkalı bileşiklerin katyonları seçici olarak bağlamaları özellikle çevre kimyasında ve biyolojik sistemlerde metal iyonlarının tespit edilmesinde kimyasal sensör olarak kullanılmaları olanağını ortaya çıkarmıştır.
Morfolin, çok sayıda farmakolojik kimyasalın yapısında bulunan önemli bir bileşiktir. Bazı türevleri analjezik, lokal anestetik, analeptik ve antimalaryal özellik göstererek farmakolojik uygulamalarda yer bulurlar. Bunun yanında bazı morfolin türevleri antimikrobiyal aktivitelerinden dolayı bakterisid, fungusid ve herbisid olarak kullanılır.
Antimikrobiyal aktivite testi, yaygın patojenlerin olası ilaç dirençlerini belirlemek, enfeksiyonların seçilen ilaçlara karşı duyarlılığını hassasiyetle incelemek amaçlarıyla uygulanır. Mikroorganizmaların duyarlılık ve direnç şekilleri sürekli değiştiği ve çoğu mikroorganizma yeni antimikrobiyal ajanlara dahi direnç geliştirdiği için çeşitli patojenlere karşı uygun antimikrobiyal ajanlar kullanılarak aktivite testi uygulanması önem arz etmektedir. Bu testin özellikle direnç mekanizması geliştirmiş Enterobacteriaceae üyeleri olan Pseudomonas, Staphylococcus, Enterococcus ve Streptococcus türlerine uygulanması daha büyük önem taşımaktadır.
Bu tez çalışmasında 4-morfolinofenoksi grubunu uç grup olarak taşıyan farklı halka büyüklüğüne sahip etilen glikol podandlar sentezlenmiş ve bunların antimikrobiyal aktiviteleri incelenmiştir.
Öncelikle 4-nitrofenol ve polietilen glikol dihalojenür veya ditosilatlardan bis(4'-nitrofenoksi) uç grubu taşıyan podandlar sentezlenmiştir. Elde edilen bu podandlar indirgenerek bis(4'-aminofenoksi) grubu taşıyan podandlar elde edilmiştir. İndirgenen podandlar bis(2-koloroetil)eter ile muamele edilerek bis(4'-morfolinofenoksi) uç grubu taşıyan nihai ürünler elde edilmiştir. Safsızlık içeren ham ürünler kolon kromatografisi ile saflaştırılmıştır. Elde edilen ürünlerin karakterizasyonları Infrared (IR) ve 1H Nükleer Manyetik Rezonans (NMR) spektrometreleri ile yapılmıştır.
Morfolinofenol bağlı etilen glikol podandların bakteri (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli NRLL B-3704, Escherichia coli ATCC 25922, Proteus vulgaris ATCC 13315, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 10145) ve maya suşlarına (Candida albicans ATCC 60193) karşı antimikrobiyal aktivitesi broth mikrodilüsyon yöntemi ile Clinical Laboratory Standarts Institue (CLSI) önerilerine uygun olarak incelenmiştir.
Yapılan çalışmalar sonucunda, test edilen bileşiklerden 5a dışındakilerin antibakteriyel aktiviteye sahip olduğu görülmektedir. Özellikle E. faecalis ve B. subtilis suşlarına karşı 5c bileşiğinin antibakteriyel etkisi standart antimikrobiyal gentamisin ile karşılaştırıldığında oldukça etkili olduğu gözlemlenmiştir. Yapılan çalışmalar sonucunda elde veriler değerlendirildiğinde daha kapsamlı çalışmalarla bileşiğin sentetik ilaç molekülü potansiyelinin artırılacağı düşünülmektedir.

Abstract:
Crown ethers are organic ring compounds, typically larger than 12 atoms in the cycle, that contain oxygen, nitrogen, sulfur or other heteroatoms. The key property of crown ethers on which interest has centered for decades is their ability to complex various ions. Initially; studies were focused on such alkali metal ions as sodium and potassium, but ammonium ion, diazonium ion, transition metals, and even neutral species were complexed by these versatile macrocycles.
Because of their ability to take up ions and to transfer them across a lipophilic medium, these types of ligands also are often called ionophores. Acyclic crown ethers (podands) and cyclic crown ethers are the main groups, which include these ionophore ligands. The first synthesized model of open-chained crown ethers is the bis(quinoline)oligoethers that its commercial name is "Kryptofix 5" whereas the first synthetic model of cyclic crown ether ligands is [18]crown-6, which was synthesized in 1967 by C.J. Pedersen. The first synthetic ionophores [18]crown-6 and dibenzo[18]crown-6, defined by Pedersen, were cyclic hexaethers. Nomenclature of these crown molecules, created by Pedersen, is simple and useful in comparison with cumbersome IUPAC nomenclature. "Dibenzo" signifies both of the benzene nuclei attached to the ring and [18] means the number of the atoms that arrange ring structure. Due to the appearance of the molecular model of these ligands and their ability to complex and cover a metal ion these first synthesized ligands molecules and other members of the series were named as "crown compounds". "Crown" is followed by the number of heteroatoms in the ring, in these cases "6".
The cation binding behavior of crown molecules are related to their structures and stereochemistry as well as the donor atoms like oxygen, nitrogen that involves in the macrocyclic ring. Interactions in such compounds between ether-donor atom and the metal ions are considered to be electrostatic. Complexation reactions of crown ether compounds with ions have been investigated in three main structure models: in the first group of structure, the radius of the cavity in the ligand matches the size of a metal ion. 1:1 complex between LiSCN and dibenzo[14]crown-4 is the example of this type of complexation. The second group of the complex structure occurs when the radius of the cavity of the ligands is too large relating to the size of a metal ion. 1:1 "wraparound" arrangement complex between K+ and dibenzo[30]crown-10 can be given as an instance to the second group. Third group complex model is observed when the metal ion is too large to match crown cavity. In these cases, complexes demonstrate 1:2 and 2:3 metal-ligand stoichiometries. 1:2 complex between K+ and benzo[15]crown-5 is typical arrangment for "sandwich" crown complexes.
Thanks to their unique ability to complex with ions and even neutral molecules, ionophore crown ligands could be used in many applications especially in phase
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transfer catalysis and sensor applications in biological systems. Their applications in modern supramolecular chemistry now extend to their uses as functional elements or structural scaffolds.
In 1954, "morpholine" functional group had firstly observed when an American search group described the syntheses of 2,6-dimetylmorpholines in which long unbranched alkyl chains attached to 4 position. This study led, at BASF, to the discovery of dodemorf, which was the first sterol biosynthesis inhibitor (morpholine fungicide) for crop protection. Over the years, studies have shown that morpholine containing compounds has many pharmacological applications. A number of morpholine derivatives have pharmaceutical applications as analgesics, local anesthetic, analeptics and antimalarials. In addition, because of their antimicrobial activity, a number of morpholine derivatives are used as bactericides, fungicides and herbicides.
In recent years, molecules having morpholine in their structure have been synthesized and especially cation binding behavior and antimicrobial activity of which have been studied. For the first time ethylene glycol podands having different ring size bearing 4-morpholinophenole as end group were synthesized and their antimicrobial activity was investigated in this thesis.
Antimicrobial activity testing is an important application of clinical microbiology. The aim of testing are to assign possible drug resistance in pathogens, to provide information about susceptibility of antimicrobial agents for common infections. Because of changing resistance type of microorganisms against antimicrobial agents and also developing resistance even to new agents, it becomes necessity to detect susceptibility of pathogens to appropriate antimicrobial agents. Therefore, it is more important to execute susceptibility testing of species that acquire resistance mechanism (e.g. members of the Enterobacteriaceae, Enterococcus species, Pseudomonas species, Streptococcus, Staphylococcus species). The macrobroth dilution method, which is still assumed as a referance method, was among to be first developed. This method is generally performed in glass test tubes containing a broth volume of >1 mL. The microbroth dilution method is an adaptation of the macrobroth dilution method using small volumes for routine testing. The antimicrobial susceptibility testing methods assure accurate results when used in accordance with the standarts defined by CLSI (The Clinical and Laboratory Standards Institute).
In this thesis, firstly the synthesis of new ethylene glycol podands bearing morpholine moiety on aromatic part was carried out. Then, antimicrobial activity of them was investigated.
At the first, the podands were synthesized from reaction of 4-nitrophenol with polyethylene glycol dihalides or ditosylate. After reduction of these compounds, podands containing bis(4'-aminophenoxy) as end group were obtained. By condensations of them with bis(2-chloroethyl)ether, the final products, morpholinophenol ended podands were obtained. Structures of all synthesized podands were characterized with spectroscopic methods such as 1H Nuclear Magnetic Resonance (NMR) and Infrared Spectroscopy (IR). Antimicrobial activity of morpholinophenol bonded ethylene glycol podans against specific bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli NRLL B-3704, Escherichia coli ATCC 25922, Proteus vulgaris ATCC 13315, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 10145) and yeast strains (Candida albicans ATCC 60193) were executed with broth
microdilution methods according to predetermined standards of Clinical Laboratory Standarts Institue (CLSI).
As a result of the studies carried out, it appears that tested compounds except 5a have antibacterial activity. When the data that was obtained from the studies are evaluated, the compound 5c (1,8-bis(4'-morpholinophenoxy)-3,6-dioxaoctane) has highest antibacterial and antifungal activity. With more comprehensive studies, it is assumed that the synthetic drug potential of the molecule can be increased.