Hidroksi ketonların fenolik bileşiklerle reaksiyonu

Abstract

Bu çalışmada, çeşitli £-hidroksi ketonların, fenol, a-naftol ve (3-naftol ile bir asit katali- zatör olan Amber 1 yst-15 yanında^ kondenzasyonu incelenmiş ve elde edilen ürünlerin yapısı aydın latılmıştır. Kullanılan $-hidroksi ketonlar ase ton, dietil keton, metil-etil keton ve metil-iso butil keton' un formaldehit ile bazik ortamda ver dikleri kondenzasyon ürünleridir. Bu reaksiyonlar da keton/CH^O uygun oranlarda alınarak, adı geçen ketonların a-monome t ilol türevleri ($-hidroksi keton) veya a, a~d ime t ilol ( 3, ft'-dihidr oks i ketonlar) türevleri elde edilmiştir. Aseton-monome tilol, asit iyon değiştirici eş liğinde fenol ile kondenzasyonu sonunda 4-(4-hid- roksif enil) -2-but anon bileşiği vermesine karşın, diğer ketonların monometilol türevlerinin fenol ile kondenzasyon ürünleri ele geçirilememiştir. Buna karşılık ketonların mono ve dimetilol türev lerinin ft-naftol ile verdikleri kondenzasyon reak siyonlarının sonunda, oldukça farklı türde, yeni bileşikler elde edilmiştir. Monometilol türevlerinden, yalnız aseton- monomet ilolün fenol ve a-naftol ile metil etil keton monomet il ölün ise 3-nâftol ile olan konden zasyon ürünleri ele geç ir il eb i İmiş tir " Metil etil ketonun monomet ilolün $-naftol ile verdiği kondenzasyon ürünü, 2,3-dimetil-3- -II- hidroksi-naf to [j2,l-b] pirandır ve monomet ilo 1 türe vi ile 3~naftoİ arasındaki kondenzasyonu takip eden molekül içi bir asetalleşme reaksiyonu ile oluş maktadır. Diğer taraftan ketonların dimetilol türevle rinin $~naftol ile kondenzasyon ürünleri kolayca izole edilmiştir. Ase ton-dimet i lol ve (3-naftol'den 7a, 15a-dihidro-7a-Metil-dinaf to [2,1-b; 2,1-gJ 4H,5H-pirano [2,3-b] piran, Dietil keton-dimet ilol ve $-naf tolden, 1,1'-- dihidro-2, 2 ' d ime t i 1-3,3 ' sp ir ob i İ3H, naf to [2, 1-bjpiran.J, Metil iso butil ke ton-d ime t i lol ve 3-naftol- den, 7a,15a-dihidro-7a-Metil-15a-isopropil-dinafto [2,l-b;2. 1-g] 4H,5H pirano [2, 3-b] pir an, Metil etil keton dimetilol ve '$-haf tolde.n,. 7a, 15a-dihidro, 7a, 1 5a-d imet il-d inaf t o [[2,1-b; 2,1-gJ 4H,5H pirano [*2,3-b~] piran' bileşikler i elde edilmiştir. Ketonların dimetilol türevleri ile g-naftol arasındaki reaksiyonlarda asit ortamda önce iki mol 3-naftol, 1 mol keton-dimet ilol bileşiği ile, 3-naftolün a yerinde kondenzasyona girmekte, son ra da, B-'naf tollere ait hidroksil grupları ile ketonun karbonil grubu arasında molekül içi ase talleşme meydana gelmektedir. -III- R H0HoC - C - CH0OH, 0 I | / 4- z C=0 I CH" OH R+ R CH0-C-CH OH f"0 OH CH. R=H,-CH -CH(CH3) 7a,15a-dihidro-dinafto-[~2,l-b;2,l-g] 4H,5H-pirano[2,3-b]piran. Asit katalizatör olarak kullanılan iyon değiş tirici reçine, hem kondenzasyon, hem de asetalleşme reaksiyonları için katalizatör ödevi görmektedir. Dinafto [2,1-b; 2,1-g] 4H,5H [2,3-b] piran türü bileşikler literatürde oldukça az sayıdadır ve sen tez yöntemleri ise oldukça karmaşık ve çok basamak lıdır. Bu çalışmada, bu tür bileşikler oldukça ko lay sentez edilebilen çıkış maddeleri ile ve tek reaksiyon basamağı üzerinden elde edilmişlerdir.

Reaction between 4-Hydroxy- 2-bu t anone and phenol yields 4- ( 4-hyd roxy-pheny 1 ) -2-but anone (Rheosmine) in the presence of a Fr i ed el-Craft s catalyst such as AICI3, H?SO,, p- t oluenesulphonic acid and acid ion-exchange resin. The reaction is an elect rophil ic aromatic substitution reaction, which involves in formation of an electrophile i.e., a carbocation or an oxonium ion. Then the electrophile attacts to ortho or para position of the phenolic ring. CH1-C-CHo-CHo-0H 3 il 2 2 H - CH.-C-CHo-Cll.,0Ho m CH--C-CH.,-CH0 3 11 2 2 2 3 11 2 2 0 0 Phenol PIkuioI ch3-c-ch2-ch^<\ /h-on 0 This is a straight forward method for the preparation of Rheosmine since older method involves two difficult steps, a Claisen-Shmid t condensation and following hydrogenation;, CH.,-C-CH., + OHC 3 |j 3 0 OH CH..-C-CH ~CH-(X }hOH \\.'?. H2/Pd -A C\i.-i-a\,rCR-'A //-OH 3 j| I 2 \_y 0 -V- In this work, the reactions between phenol/ napthols and a number of 8-hydroxyke tones were studied in the presence of ion-exchange resin. B-hydroxy ketones were prepared by aldol condensation reaction between corresponding ketones and formaldehyde in the presence of an alkaline catalyst such as NaOH. Furthermore, $, (3-d ihydroxyket ones were prepared and reacted with phenol /nap tho 1 s in the presence of strong acid ion-exchange resin. B-hydroxy ketones such as methyl ethyl ketone me thy 1-isobu thy 1 ketone showed self -polymer iz at ion instead of condensation of phenol. However, more reactive phenolic compound, i. e., $-naf tol, resulted condensation reaction products. Among the napthols, (3-napthol was a good candidate for condensation since it contains only one activated position, (a) position for substitution so that single substitution product would form. a-Napthol which contains activated ortho and para position to its hydroxyl group was reacted with 4-hydr oxy- 2-butanone and gave a product of para substitution. This is a similar reaction between 4-hy droxy- 2-but anone and phenol. 0 H - CH0-C-CH0-CH 3 II 2 0 Reaction product of $-napthol with methyl ethyl keton-monomo thylol is 3H, 2, 3-dimethy 1-3- -VI- hydr oxy-nap tho J2,l-b J py ran. The reaction probably proceeds through condensation reaction between one mole of each compound and then intramolecular acetallization reaction. _ Ln." /H-Ç-CH. CH3-C-CH-CH9OH + ^ ^-OH 0 CH. C-CH, 3H, 1, 2-dihydro-2, 3-dimethyl-3- hydr oxy-nap tho (j2, 1-bjpyran In this reaction, the strong acid ion-exchange resin should act as catalyst for both condensation and acetallization reactions. This type of catalyst are known to be effective for both type of reactions. On the other hand, the reaction product of |3-napthol with aceto n-dimethy lol was 7a, 15a-dihydro-, 7a-Methyl-dinaptho [2,l-b;2,l-g]4H, 5H, pyrano[2,3-b] pyran. Here, the reaction presumbles proceeds via condensation between one mol 3, fadihydroxyketone and two mol 3_napthol following intramolecular acecal formation as shown below. -VII- HOH2C-CH-CH2OH 0=0 I + z CIT z I OH C=0 OH I CH" CH /CH ÇH c=oh 1} 7a, 15a-dihydro-7a-Methyl- dinaptho(2,l-b;2,l-g] 4H,5H pyrano [2,3-bjpyran. Methyl ethyl ketone-dimethylol and ft-napthol produced 7a,15a-dihydro-7a,15a-dimethyl-dinaptho [2,l-b;2,l-g]4H,5H pyrano [2, 3-b]pyran which was again the result of condensation and subsequent intramolecular ace tallizat ion reactions. CH-, I 3 cr° H0HoC - C-CH_OH 2, 2 CH. OH 2) Ac e t -VII I - Similar results were obtained from the reaction of me t hy 1 - i sobu ty lketone-d ime thy 1 o 1 and (3-napthol. CH" 1) ComL 2) Acet. HOH"C-C-CH.,OH +. 2 | 2 2 CH3 CH 7a,15a-dihydro-7a-Methyl- 15a-isopropyl-dinaptho [2, 1-b ; 2, 1-g] 4H, 5H, pyrano ]~2, 3-bj pyran However a spiro compound, ?, I '~ dihydro-2,2,dimethyl-3,3 * [spirobi 3H-naptho [2, 1-bj- pyranj was obtained when d ie t hy 1 k e ton-d ime t hy lo 1 was reacted with B-napthol in the presence of ion exchange resins. This product could only be formed if dimethylol compound was a, ad imethy lo 1 of diet hy Ike t one. 0 CHo01! II I 2 CH..-CH-C-CH-CH., + 2 J I -> ^s CH2OH The structure of these products were determined bv their mi:;.' aiidJysi,-;, me.i f i. n }>, p^int, IR, H. NMR and Mass spectrum. -IX- From these results, It can be concluded that, the reaction products between ^-hydroxy ketones and phenolic compounds are determined by the type of both reactants. When |3-napthol was taken as phenolic compound intramolecular acetal formation was always observed. The choice of the catalyst is also important since it shoud be effective for both condensation and acetal formation reactions. Amber 1 ey s t-1 5 is the most suitable catalyst for this purpose. This macroporous cationic resin does not contain any water. The water evolved during the condensation and acetal formation is absorbed by the sulphonic acid groups of the catalyst. Thus, it acts as catalyst and drying agent for acetallization so, reaction isaccelarated.