Bazı kumarin türevlerinin sentezleri ve UV spektrumları
Synthesis of some coumarin derivatives
- Tez No: 75517
- Danışmanlar: PROF. DR. ÇAKIL ERK
- Tez Türü: Yüksek Lisans
- Konular: Kimya, Chemistry
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 1998
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Kimya Ana Bilim Dalı
- Bilim Dalı: Organik Kimya Bilim Dalı
- Sayfa Sayısı: 88
Özet
ÖZET Tez çalışmamda, kumarin grubu bileşiklerin ve türevlerinin sentezi yer almaktadır. Kumarin sınıfı bileşiklerin genel gösterimi aşağıdaki gibidir. Kumarin Kumarin grubu bileşiklerle çalışmamızın sebebi; halka üzerindeki sübstütüe grupları hidroksile çevirmek ve önce“podand”türü dimerleştirilmiş ürünleri; daha sonra da halka kapanma reaksiyonu ile taç eterleri oluşturmaktır. Bu amaçla yapmış olduğumuz deneysel kısma ait reaksiyon şeması aşağıdaki gibidir. CH390 CH3COCH2COOEt 1a a. AICI3 / PhNOj OH or poci3/ZnCI2 O, OH 1b b. NaOH / H202 2a-3a CH3 E Şema 1. Etilasetoasetattan yola çıkarak bazı hidroksiasetil kumarinlerin sentezi. Buradan da anlaşılacağı üzere; önce kumarin türevlerinin sentezi daha sonra bu türevlerin dihidroksi formuna çevrimi söz konusudur. Oluşturulan dihidroksi kumarinler üzerinde hem“podand”oluşumu hem de aynı halkada“crown”oluşumu reaksiyonları denenmiştir. Deneysel çalışmalarımızdaki kumarin sentezi aşamasında özellikle A1C13 gibi güçlü Lewis asitleri kullanılmıştır. Kullanılan aside bağlı olarak halkadaki yönlendirmenin değiştiği ve ağırlıklı olarak hangi kumarin türevlerinin uştuğu, bu izomerlerin birbirinden ayrılma yöntemleri üzerinde de çeşitli çalışmalar yapılmıştır.
Özet (Çeviri)
SUMMARY SYNTHESIS OF SOME COUMARIN DERIVATIVES Synthesis of various coumarins were achieved using different Lewis acids. The resultant coumarins introduced by dichloride of polyglycols in potassium or sodium carbonate/DMF/water gave podands in satisfactory yields. UV spectroscopy was used to detect the ion-ligand interaction of alkali and earth-alkali ions (Scheme 1). Scheme 1. Synthesis of Coumarin-Podands The fusion of a pyrone ring with a benzene nucleus gives rise to a class of heterocyclic compounds known as benzopyrones, of which two distinct types are: 1) benzo-a pyrones, commonly called coumarins, and 2) benzo-y pyrones, called chromones, the latter differing from the former only in the position of carbonyl group in the heterocyclic ring (Scheme 2)./v\ Vv%> Scheme 2. Coumarin and Chromone Coumarin, the parent substance of the benzo-a pyrone group, was first isolated from tonka beans in 1820. Particularly the plants belonging to the natural orders of Orchidacese, Leguminoceae, are rich sources of naturally occuring coumarins. Coumarin was initially considered to be a benzoic acid derivative, but its synthesis by Perkin, Sr., from saicyl aldehyde by means of his classical reaction established its relation to o-hydroxycinnamic acid which a molecule of water in forming the lactone ring. Thus coumarins and their derivatives are, from the point of view of their chemical constitution, a group of lactones derived from o-hydroxy cinnamic acids: alternately stated, a coumarin ring system is formed by the fusion of a benzene and a 1,2 pyrone ring, in other words coumarins are a class of heterocyclic compounds containing oxygen as a member of the heterocyclic ring. Coumarin and their derivatives are substances of much potantial value for synthetic purposes. Their easy accesibility opens the way through suitable reactions to the synthetic preparation of various other heterocyclic compounds, such as coumarones, furanocoumarins, chromono-a pyrones, flavono-a pyrones, and chromenes, as well as naturel products containing such ring systems. Coumarones are a degradation product of coumarin in which the five membered ring is obtained from the pyrone ring. Several coumarones have been prepared from coumarins in this way. Coumarones are used in industry for the manufacture of coumarone resins (Scheme 3-a). If the furan ring is built on a suitably substituted coumarin or chromone derivative, it leads to the synthesis of coumaronocoumarins, generally known as furanocoumarins (Scheme 3-b). Coumarins either in the free or in the combined condition are found to occur in different parts of the plant. The coumarin-bearing plant, after suitable preliminary treatment, is extracted with a solvent and the extract is then subjected to various processes for isolation. Coumarins obtained from plants are devided as below, 1) Coumarins and its simple derivatives 2) Hydroxy and metoxy(alkoxy)-coumarins and their glucosides. The hydroxy or alkoxy group may be present in the benzene or the pyrone ring. 3) Hydroxy or metoxy-coumarins with an alkyl group in any part of the ring system. 4) Furanocoumarins(furan ring fused to benzene ring) with a) an unsubstituted furan ring and b) a substituted furan ring.5) Coumarins with a 2,2-dimetyl-l,2-chromene ring. NaOH ^> -CO, (a) ?*. I ^^ (b) Scheme 3. Syntheses of Coumarons and Furano-Coumarins At present over fifty natural coumarins are known and their chemical constitutions established. Coumarins have been found to be physiologically effective for animals as well as men. Levadhti, Ellinger, Bergstrom, Rai and Trendenburg have done the main work in this field. XIIt has been observed that coumarin acts as a narcotic for rabbits, frogs, earthworms and many other animals. It is a sedative and hypnotic for nüce. In men as well as dogs its toxic action is predominant. A dose of about 5 gr. kills a sheep; the fatal dose for horses and cattle is about 40 grams. Although over forty coumarins have been tested, many of them show a poisonous effects. The hydroxy coumarins have been found to be less effective, though toxicity increase considerably on methylation. For human beings, coumarin has a slight toxic effect. The first dose, to the extent of 4 gr., produces the symptoms of illness and weakness. It has no definite injuries effect on the heart; it checks the reactivity of the sympathetic nerves and paralyzes the flat muscles. Mannich has found that some hydoxy coumarins possessing the power of absorbing uv light are extensively used as medicines in skin diseases. The coumarins of most popular benzo-ct pyrone group have been extensively used as the colour compounds since they were recognised as the strong pigments, which are, in particular, stable in acids and at high temperatures. The various types of coumarins of potantial pigments widely obtained from the natural sources have been synthesised with different methodes. The chemistry of such compounds were therefore well documented. They have been recently used for the optically reponsive sensors for the molecular recognition. The strong acids have been mostly used for the condensation of the suitable phenols to prepare the dihydroxy coumarins. We have been mostly considering the synthesis of the dihydoxycoumarins for the preparation of their macrocyclic derivatives of optical cation receptors. We have recently developed the synthesis of such compounds likewise Daphnetin and Aesculetin via a condensation in HCIO4. However, the preparation of the chromogenic and fluorogenic macrocycles prompted us to study on the unproved synthesis of the dihydoxy derivatives of the different chromophores. The present work deals with the synthesis of some dihydroxy derivatives using strong acids to promote the coumarin condensation where the protonic acids had mostly failed. However, such agents have been previously used by the well known authers. Sethna, Shah and Shah have used the AlCynitrobenzene succesrully for the condensation of the hydoxyacetophenone derivatives with P-ketoesters succestully. Desai and Hamid have first reported the condensation of the reacetophenon with ethyl acetoacetate forming 7- hydroxy-6-acetyl coumarin. However, we used both of the agents of AICI3 and POCI3 individually and investigated the condensation products of hydroxyacetyl coumarins formed with ethyl acetoacetate (Scheme 4). xuCH3COCH2COOEt ? a. AICI3 / PhN02 OH or POCI3/ZnCI2 O 1a b. NaOH / H202 OH lb 2a-3a CH3 E Scheme 4. Syntheses of some hydroxyacetyl coumarins from ethyl acetoacetate. Xlll
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