Bazı t-siklik karbinollerin dehidrasyon ürünlerinin incelenmesi

Abstract

Ill ÖZET Alkollerin dehidrasyonu alken! erin sentezi için kullanılan genel reaksiyonlaraan biridir. Bu amaçla değişik dehidrasyon vasıtaları kullanılarak işlem ho mojen veya heterojen ortamda yapılabilir. Homojen or tamda, çözelti fazında alkolleri olefine dönüştürmek için proton veren asidler (Brönsted asialeri), Lewis asidleri, as i d i£ u uz lar, asid anhidritleri ve halo 3 en li bileşikler kullanılabilir. (Heterojen ortamda isef alkol buharlarının metal oksitler ve susuz metal sül fatlar gibi katı katalizörler üzerinden geçirilmesi ile kolaylıkla olefine dönüşürler. Çalışmamızda 1-Penil, 1-Jj'enilmetıl, l-iteniletil, l-i?'enilpro pil grubu içeren bazı tersiyer siklik karbi- noller sentez edildi ve dehidrasyon ürünleri incelen di. Tersiyer siklik karbinolleri sentez etmek için arıl ve arilalkil halo jenürlerden elde edilen organo- magnezyum bileşikleri ve karbon sayısı n=12,15f10 olan siklik ketonlardan faydalanılmıştır. Bu şekilde 1-Fenilsiklodoiekanol, 1-Penılmetılsikloaodekanol, i-i?eniletilsiklododekanol, l-tfenilpropilsiklododeka- noi, 1-Jj'eniisiklopenxadekanol, i-Fenılmetılsiklopen- tadekanol, l-Penilmetilsikiodekctnol sentez edildi. Çözelti fazında yapılan aehidrasyon işlemleri için üç ayrı met od kullanılmıştır; 1. To^uenii ortamda h^K). 2. Piridinli ortamaa tiyonil Jfclorur 3. Çözucüsüz ortamda y> 8î>'1İk. h2S04.IV Toluenii orxamda H^PO, ile reaksiyon, sentez edilen tüm jcarbinoılere, Piridinli ortamaa tiyonil klorür ile reaksiyon sikloaodekanoi nal&ası içeren tüm kar- binollere, % 8i> lik ttoS04 ile reaics:Lyon 1-^eniletil- siklododekanol'e ve l-Fenilpropılsiklododeıcanol' e uygulandı. i*oiuenli orsamda ^3-^4 ile yapılan reaksiyon larda, tek cins p> -hidrujcn içeren 1-FenılsiKİodode- kanolden ve 1-Fenilsiklopentadekanolden tek cins eliminasyon ürünü yani 1-Fenilsiklododesen-l (cis + trans) ve 1-FenilsiiU.opentadesen-l ( cis+trans ) sentez edildi. Bu olefinler 254 nm lik, 16 Mr iık düşük basınç cıva lambası ile iş inland ir ıldıklarında cis olefinin trans olefine dönüştüğü tespit edildi. Diğer arilalkil siklokarb incilerden ise iki farklı p-nidrojen içerdik leri için ekso ve endo isomerler karışımı içeren iki cins eleminasyon ürünü sentez edildi. 1-Benzilsiklo- dodekanolden % 96,97 oranında 1-Benzilidensiklododekan (ekso) ve % 3 oranmaa l-Benzilsiklododesen-l;l~J3en- zilsikiopentciacdcanolden 7° 79.73 oranında 1-Benziliden- siklopenxadekan (e&so) ve % 20.36 oranında 1-Benzil- siklopentadesen-1, sentez edildi. 1-Benzilsiklodeka- nolden ise % 10û oranında 1-Benzilsiklodesen-l (endo) elde edildi. l-Feniletılsıklodoaekanclden Ş> 9 oranında 1-Femletilidensiklododekan (e£soj ve 7° 89*12 oranında 1-Feniletılsiklododesen-l, 1-Fenilpropilsiklododekanol- den ise % 34 oranında İ-Fenilpropiiidensiklododekan (ekso) ve % 52.16 oranında 1-Feniipropilsiklododesen-l sentez edildi. Olefin karışımlıma ayrıca % 13.81 ora-randa siklodenidrasyon sonucu oluşan spirö [siklodo- dekan-1:!1- tetralin] bulunmaktadır, Piridinli ortamda tiyonil klorür ile yapılan reaksiyonlarda 1-Fenilsiklododekanolden substitusyon ürünü olan 1-Penil İ-Klorsiklododekan, 1-Fenilmetil, 1-Feniletil, 1-Fenilpropilsikioaoaekanollerden ise toluenli ortamda H^K), ile elde eailen dehidrasyon ürünleri gibi, farklı oranda ekso ve endo isomerler karışımı içeren aynı olefinler sentez edilmiştir. l-Fenil, 1-Penilmetil, i-Feniletil, 1-Fenilpro- pilsiklododekanoller 240°C injeksiyon sıcaklığında Silicone OV x 17 % 3 lük gaz likit kromatografi (GLC) kolonuna uygulandıklarında dehidrasyona uğradıkları tespit edildi. Çozücusüz ortamda % 6b lik HpSO, ile yapılan reaksiyonlarda halka kapanması sonucu siklodehidra. syon ürünleri elde edildi. 1-Feniletilsiklododeıc<inol- den, siklododekan [1>2.,11,2*] tetralin; 1-Fenilpropil siklododekanolden ise spiro [sikiododekan-l:!1- tetra- linj sentez edildi.

VI SUMMARY The dehydration of alcohols is one of the com mon methods for the synthesis of alkenes. The proce dure can be observed both in the solution and in the gase phase. Different types of dehydration agents can be used and the reactions can be proceeded in homogeneons or. in heteregeneous media. I?or homogeneous reactions dehydration occurs under strongly acidic conditions, & range of acidic reagents such as Brönsted or Lewis acids, iodine, acidic salts, acid anhydrites and halogen compounds can be used* Under heteregenous conditions, dehydration can be perfor med, by passing the alcohol vapours over heated cata- liysts such as metal oxide or anhydrous metal sulfates. Depending on the reaction conditions several x: mechanisms are used. When a strong mineral acid is used f the alcohol is protonated and breaks down in an B-, reaction. Â similar reaction occours in the tertiary alcohols and some secondary alcohols are dehydrated by heating with traces of iodine, Gertain acids (e.g. H^SCh, oxalic), anhydrites (e.g. boric, phtalic, acetic) and other reagents (e«g«, P0C1- in pyridine, ?2U5 in J^lene^ maJ also form esters which subsequently decompose either thermally, or by E-, or E2 pathways especially by refluxing in high-boiling solvents. Only when an alcohol contains a ş, -hydrogen that is activated by earbonyl groups or double bonds, direct dehydration by bases can be achieved.VII In this research, first some t-cycliccarbinols were synthesized, then their dehydration products were investigated. t-Cycliccarbinols that contain 1- phenyl, 1-phenyliaethyl, 1-phenylethyl and 1-phenyl- propyl groups were prepared with Grignard reactions as follows: Mg C6H5-Br -rr-> CgH^-MgBr /^*N H0 CgH^MgBr--^ (CH2)n C=09 C^-C (^H 1-lhenylcyclododecanol By this way, 1-phenylcyciopentadecanol, 1-phenylmethyl- cyciododecanol l-phenylmethylcyclopentadecanol, 1-phe- nyJLniethylcyciodecanol, 1-phenyiethyloyclododecanol, i-phenylpropyicyclouodecanol were synthesized. For the dehydration process in liquid phase three metnoas were used: 1- H_EO- in toluene, 2- SOClp in pyridine, 3- H2SO. (£8i>) without solvent Q?he first metnod was applied to all of the carbinols, the second one was used for t-cyciic carbinols contain ing cyclodecane ring and the third mexnou was only used lor 1-phenylethyl and 1-phenylpropyl cyciodode- canol* In tne reactions that were prîörmed with H-PO. in toluene, the hydroxy! group of alcohol is converted into a better leaving group (OnX) ana the subsequent decompositions ofter involved carbonium ion ınt ermedi-VIII atcs, acorcting to E, mechainsm. Then, as a- result of leaving of £ -hyarogen, ulerin is lormea. 1'ne num ber of elemınatıon products is depenucnt on the kind of p -nydrogens of the carbinois, iî'or instance, jL-phenylcyelodeeanol gives only one elimination pro duct, 1-phenyieyclodecene-l because it contains only two equivalent ^-hydrogens: e6H5-a HoO <CH2>n H o 0 (CVll C6H5-C (CH2)1]L -H -H20 C6H5-° (^2)0 l-Phenylcyclododecene-l To determine the olefin, GLC is applied and two peacks are obtained (Rt: 0. 67* tmd 6. 56* 92`31 % and 6.10 % respectively)» Here, it is possible? to form two geo metrical isomers of 1-phenylcyclodecene-l» To identify cis and trans isomers of the olefin, the product was irradiated in $L atmosphere using 254 nm, low pressure tig immersion lamp for 24 hours. Results of GLC, UV, IR and HMR analysis indicated tnat cis form of 1-phe- nylcyclododeeen-1 is converted into trans form. '°/ho (CHQ.) 2'lu /G6H5 cis olefin trans olelinIX Similarly, 1-phenylcyclopentadecene-l was obtained from 1-phenylcyclopentadecanol and the result of photc isomerisation, the cis iorm of the olefin was conver ted into trans form. The carbinols that involve two different Kind p -hydrogen gave two different elimination products. These products are the mixture of endo and exo isomers For instance, 1-Benzylidencyelodecane (exo) and 1-Ben- zylcyclodecene-1 (endo) were obtained from 1-BenzyI- cyclododecanol : ?^-N H+ %9/^N -H20 C6H5-CH2-C (Ch2)9 tA-^ C6H5-CH2-C (CH2>g - £-> C6*5-T// <CH2>9*C6VCHzCx <CB2>9 Uxo) C6H5-CH2-C (CH2)g (endo) In the similar way, 1-benzylidencyclopentadecan (exo) and 1-benzylcyclopentadecene-l (endo) were synthesized from 1-benzylcyciopentadecanol. The amount of exo olefin in the dehydration products of these carbinols was found xo be greater than that of endo isomer. On the contrary, the previons studies indicated that the amount of endo cyclic compounds present in the dehyd ration products of the benzyl cyclic carbinols that have carbons up to n=5,....8 in the cycloalkane groupis higer than that ot exo cyclic compounds. In this research, the dehydration products of l-benzylcyclo- aecanoi in acidic conditions is investigatüu. etna it.... is seen that only endo olefin is obtaxnd, 1-benzylcyc- lododecene-1, just as literature predicts. Partition of endo ana exo isomers in the dehydration producxs of benzylcyclocarbinols and the chemical »hilt values obtained by KMR analysis are listed in Table 1 as follows: Table 1 : Dehydration products of 1-Benzylcyclocar- binols a- Studied in literature, b- Sxudied in this work In acidic medium, 1-Phenyletnyleyclodecanol gave 1-phenylethylidencyclododecan (9oü %9 exo) andXI 1-phenylethylcyclododecene-l 189.12 %, endo) too. From l-phenylpropylcyc±ododecanol, 1-phenylpropyli- dencyclododecane (34 %fexo) and l-phenylcyclododecene~l ( 52#16 f>, endo) was obtained. In addition, spiro jcyclocLodecane-l:lf~tetralin3 (13 »8 % ) was found as cyclodehydration product in the mixture..^,. In the reactions that were made with S0C12 in pyridine, the OH group is converted into 0S0C1 to leave easily. Ester intermediates that are produced during reaction, decompose either unimoleculer (En)> or bimoleculer (iSp) or thermally and give the elimi nation products. H H -C-C-OH `IvI^ni^J> -G-C-0S0C1 -~~2'' `~~ > *)c-c( } i S0012% Py If ~S0P, -HC1 -Py.HC1 1-phenyleyclododeeanol, unlike arylalkyleyclododecanoIf gave 1-phenyi-l-chlor cyelododeean? a substitusyon product j instead of 1-phenylcyclodecene-l, an elimina tion product. That is, SüCl2 reacted as a halogenation agent. The reaction is formulated as following. OS0£l S0Cl2:Py (/, X ~S02,-C12 C6E5-C (CH.^^Jg^C^.C' (CH2)9 (GH2)9> G6H5^G ^E2y9 -f~Cl 1-phenyl- l«rchlor cyclododecanXII According to E, mechanism, unstable ester intermediate easily converts into the earbocation and the chloride ion attacks as a strong nucleophille. As a result, chlorination occurs before the transfer of 3 -^lidrogen. The dehydration obtained fromt 1-phenylmethyl, 1-phen- - ylethyl, 1-phenylpropylcyclodecanole with S0C1 in pyridine are similar to the dehydration products ob tained from same reactants with H-K). in toluene but their endo to exo olefin ratio values are different. With the separation of 'p -hydrogen and as result of leaving group from the intermediate of ester that these are taking place at the same time the mixture of olefine that consists of.exo and endo isomers, are synthesized, For instance, 1-phenylpropylidendodecane (exo) and 1-phenyl propyl eyclododecen-1 (endo) are synthesized from 1-phenylcyclododecanol according -co the following reactions. OH S0Cl2:Py cıoso _ 1/ N C^-fCH^-C ^)9 - » CgH^CH^-C' (CH2)9 endo C^-İCHgîg-Cttr/ (CH2)9 exoXIII AUso, when 1-phenyl, 1-phenylmethyi, 1-phenylethyl, i-phenylpropylcyclododecanols are applied on Silicune OV-17 (%3) GIG column at 240°C injection temperature, it is observed that pyro lit ic eli mined; ion products are obtained. The elimination products obtained from H^PO, in toluene, S0C1 in pyridine and pyrolitie elimination on the column are listed in table 2 : Table 2. Partition of end o and exo isomers. Compounds H^KK In the- column S0Cl2:Py -eyclodo-* % % ?& % ' % % decanol exo enao exo endo exo endo 1-B^n^rl`- 1-Bienyl- methyl 1-Hienyl- «thyl i-Phenyl- propylr-.92.31 ' - 96.97 3 90.5 27.2 71.2 23 34 52.1 47 87.39 chlorination 9.5 53 58.25 33.64 76.16 9 89.12 27.54 t>6.53 The aeny drat ion reactions carried out in KLSu. ($85), cyclodehydration products Ter^ only obtained from 1-phenylexhyleyclododecanoi and l-phenylpropyl- cyciodudecanol. as a result xhe reactions shown beiuw cyciododecone £1,^,1', 2* J tetralm anu spiro [cyc±o~ dodecane -itl^-indan] are obtained from 1-phenylethyl- cyclododecanol. The reactions are tormulated as following;XIV OH- H2S04 -HgO epiro fcyclododeeane- 'ljl'-indanj cyclododecane Q.,2,11,2'J tetralin Prom the results of GLC analyns, two compounds were detected, but only one of them can be purified, this is cyclododecane [1,^,1*,2'Jtetralin. Theoritically expected compound was spiro [cycloaoceean - 1:1'- indanj but it could not be determined. Since the six carbon ring is a more stable product spiro [cyclododecane 1:1» tetralin J was easily syntnezied from 1-phenylpropylcyclododecanol» This can be observed from the following reactions: H H2S04 -H20