Polienonlara amin ve amino asitlerin katılması

Dialdehitlerin aseton veya aktif metilen içeren başka bileşiklerle kon- densasyonuyla elde edilen polidienonlar çözünmezlikleri yüzünden çok az ilgi görmüşlerdir. Polidienonlarm tam eşlenmiş bir sistem elde etmek amacıyla incelenmelerine rağmen, ortaya çıkan maddelerin elektriksel iletkenliğinin çok az olduğu bildirilmiştir. Bu maddeler genellikle düşük birleşmeye. isacsfc eden açık. veya koyu kahverengi rengindedirler. Diğer yandan, enonlann karbon-karbon çift bağları nükleofilik katılma reak siyonlarına uygundur. Örneğin, aminlerin Michael tipi katılması amino ketonları oluşturur. Amonyağın mesitiloksit ile reaksiyonu 2 amino izo- propil metil keton verir. Bu çalışmada, tereftalaldehidin asetonla kondensasyonu sırasında o- luşan çift bağlara amino asid gruplarının katılmasını inceledik. 0 n 0HC--CH0 + H3C-C-CH3 + 0 -+HC-^)-CH = CH-C-CHJ=n+NH2 «JH2 0 n C00` -[hÇ - - CH II CH c=o I CH, NH2-OH ©- CH-NH-OH I CH, I z c=o I CH, This reaction seems to be general for all enones. A simple dienone, 1,4 benzoquinone also reacts with amines to give amino substituted quinone. R-NHa it O NH-R NH-R oxid. NH-R XThe intermediate hydroquinone is reduced by unreacted qiunone in the mixture to form aminoquinone. This reaction has recently been used to obtain thermally stable polyquinones, starting from 1,4 benzoquinone and a suitable aromatic diamine. H#-(Cjy-HH> J^HM^O^-I» U 9 -in o n In the stud^kbenzalacetone was chosen as the..model compound and, its amino acid addition capabiHty was tested by interacting with glycine and L-alanine.. ' O NH2. ff + R-CB *~ (( J>- CH-NH-CH-COOH COOH 9^ c=o uuüh r c=o I CH, H-NMR spectra and potentiometric titration of the resulting product establish the proposed addition compound. At the second step of the study, acetone-terephtalaldehyde polymer was prepared. By adjusting the amount of the catalyst NaOH, we were able to prepare soluble acetone-terephtalaldehyde polymer which has molecular weight 4600. The higher amounts of NaOH in different sol vents resulted in formation of insoluble polymers. H-NMR spectra of the soluble polymer represent a similar pattern with those given by Kaul and Fernandez. In the spectra, the peak around 6, 10 ppm, has been assigned as proton of enolate form by these authors. However, no evidence has been indicated on this point. The same peak is also observed in our case. However, we also observed additional aliphatic proton peaks between 2,5-3,5 ppm. Also the signals of enolate protons are not observed at so much lower frequencies. For this reason, the signal at about 10 ppm cannot be assigned to enolate proton. Instead, it must belong to aldol proton which forms at the first step of interaction with acetone. Because of this fact, aliphatic proton signals are also observed. This signals must represent aldol proton prior to dehydration step. Attempts to addition of glycine and alanine to the acetone-terephtal aldehyde polymer gave different degree of additions ranging from 36-62%, depending on the reaction time and the solvent used. It is interesting to note that, after addition of amino acids, the poly- XImer becomes totally soluble in water. This is also another clear evidence of amino acid addition to the polymer. Moreover, we have treated the insoluble acetone-terephtalaldehyde polymer with excess of ethanol amine. Ethanol amine behaves both as reagent and solvent. After addition of ethanol amine, the product sur prisingly becomes soluble in ethanol amine itself and it is also soluble in acidified water. This observation clearly indicates that insoluble acetone- terephtalaldehyde polymer is not in crosslinked form. As a consequence, active ethylenic groups in acetone-terephtalalde hyde polymer is suitable for addition of amino acids and various amino compounds, including proteins. And the method presented here offers a new route to prepare amino acid containing polymers. These new polymers are expected to find var ious applications in medicine and physical chemistry, etc. xu 50