Sikloalkenlerden sentezlenen geminal dibromosiklopropan halkasının su, metanol ve asetik asit çözücülerinde açılma reaksiyonlarının incelenmesi
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2004
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info:eu-repo/semantics/openAccess
Özet
Sikloalkenlerden Sentczlenen Geminal Dibromosiklopropan Halkasının Su, Metanol ve Asetik Asit Çözücülerinde Açılma Reaksiyonlarının İncelenmesi Karbenler, yüksüz, iki bağ yapmış karbondan oluşan ara ürünlerdir. Oldukça reaktif olan bu ara ürünler, birçok önemli reaksiyonun oluşmasını sağlarlar. Bu reaksiyonlardan biri de, alkenler ile olan katılma reaksiyonudur. Karben ile alkenin katılma reaksiyonu sonucu, siklopropan halkaları oluşur. Dibromosiklopropan halkası, bazik ortamda bromoformdan elde edilen dibromokarben ile alkenin reaksiyonu sonucu çok kolay oluşturulabilir. Daha sonra uygun reaktiflerle, halka genişletilebilir. Yapılan deneysel çalışmada, alken olarak siklopenten, sikloheksen, siklohepten, siklookten, siklododesen ile 1 -metil sikloheksen ve 1-fenilsikloheksen seçilmiştir. 1 -metil ve 1-fenil sikloheksen, iki aşamada elde edilmiştir. Birinci aşamada, sikloheksanondan yola çıkarak uygun reaktiflerle alkol elde edilmiştir, ikinci aşamada ise oluşan bu alkolün eliminasyonu ile alkenler elde edilmiştir. Başlangıç maddeleri olan bu alkenler, bromoformun potasyum tersiyer bütoksit ile olan reaksiyonu sonucu oluşan karbenle reaksiyona girerek bisiklo yapısmda olan dibromosiklopropan halkalarını oluşturmuşlardır. Oluşan dibromosiklopropan halkaları, AgNÛ3 ile DMF, DMSO, aseton gibi farklı çözücü sistemlerinde, H2O, CH3OH ve CHaCOOH'de ayrı ayrı açılmıştır. Reaksiyon sonunda ele geçen ürünler kolon kromatografisi ile saflaştırılmış ve safiaştırılan her ürünün İR ve NMR spektrumlan alınmıştır. Spektrumlara dayanarak oluşan ürünlerin yapılan aydınlatılmaya çalışılmıştır.
Ring Opening Reaction of Geminal Dibromocyclopropane Ring Obtained From Cycloalkenes in H20, CH3OH and CH3COOH Carbens are intemediates which contain uncharged divalent carbon. This intermediates which give many reactions are quite reactive. One of these reactions is addition reaction to alkenes.A cyclopropane ring forms as a result of the addition reaction between carbene and alkene. Dibromocyclopropane ring may be obtained from bromoform and a strong base. Then it is possible to open the ring by using a proper reactive substance. For the experimental studies cyclopenten, cyclohexen, cyclohepten, cyclooctene, cyclododecene and 1-methylcyclohexen, 1-phenylcyclohexen were selected as alkenes. 1-methylcyclohexen and 1-phenylcyclohexen were obtained by two steps. In the first step alcohols were obtained from cyclohexanone and suitable reactants by using Grignard reactions, hi the second step, alkenes were obtained by elimination of water from the alcohols. As starting substances, alkenes give reactions with carbene which obtained from the reaction of bromoform and potassium tert-butoxide. Dibromocyclopropane rings were-opened with AgN03 in different solvents like DMF, DMSO, acetone with H20, CH3OH, CH3COOH one by one. Products which form after the reaction were purified with column chromatography and IR, NMR spectrums were taken for each purified product. At the end, structures of pruducts were determined by using the spectra.
Ring Opening Reaction of Geminal Dibromocyclopropane Ring Obtained From Cycloalkenes in H20, CH3OH and CH3COOH Carbens are intemediates which contain uncharged divalent carbon. This intermediates which give many reactions are quite reactive. One of these reactions is addition reaction to alkenes.A cyclopropane ring forms as a result of the addition reaction between carbene and alkene. Dibromocyclopropane ring may be obtained from bromoform and a strong base. Then it is possible to open the ring by using a proper reactive substance. For the experimental studies cyclopenten, cyclohexen, cyclohepten, cyclooctene, cyclododecene and 1-methylcyclohexen, 1-phenylcyclohexen were selected as alkenes. 1-methylcyclohexen and 1-phenylcyclohexen were obtained by two steps. In the first step alcohols were obtained from cyclohexanone and suitable reactants by using Grignard reactions, hi the second step, alkenes were obtained by elimination of water from the alcohols. As starting substances, alkenes give reactions with carbene which obtained from the reaction of bromoform and potassium tert-butoxide. Dibromocyclopropane rings were-opened with AgN03 in different solvents like DMF, DMSO, acetone with H20, CH3OH, CH3COOH one by one. Products which form after the reaction were purified with column chromatography and IR, NMR spectrums were taken for each purified product. At the end, structures of pruducts were determined by using the spectra.
