Naslov
Diastereoisomerization and X-Ray Crystal Structure of meso-di-(2H-Chromene-2-yl)-ether

Autori
Lončar, Linda ; Mintas, Mladen ; Hergold-Brundić, Antonija ; Nagl, Ante ; Trötsch, Thomas ; Mannschreck, Albrecht

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
XIV skup hrvatskih kemičara

Mjesto i datum
Zagreb, Hrvatska, 06.02.1995. - 08.02.1995

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
diastereoisomerization ; di-2H-chromene-2-yl-ether

Sažetak
Compared to relatively numerous studies on photochromic behaviour of 2-H- chromenes or 2-H-1- benzopyransl which consists of a reversible photoisomerization involving a rupture of the C(sp3 ) – O bond, only a few similar reports on thermochromism in this of compounds are available. Our interest in chiral chromenes was related, therefore, to separation of their enantiomrs and determination of barriers to electrocyiclic ring opening reaction via thermal racemization of enantiomers. 2, 3 This investigation is concerned with thermally induced diastereoisomerization od di-2H-chromene-2-yl-ether l which has been shown by X-ray crystallography to exist exclusively in the meso form, i.e., 2-(S)-2'– (R)-1 . This double electrocyclic reaction which consists of ring opening and reclosure of the C- (sp3)-O bonds in l leads to converion of l to its deastereomers 2- (R)-2'– (R)-l and 2-(S)-2'– (S)-l. This diastereomers are present in the form of recemic mixture as has been proved by separation of their enantiomers using liquid chromatography on triacetylcellulose.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA