Synthesis and UV/Vis Spectroscopic Properties of Chiral Symmetrical Pentamethinium Cyanine Dyes with 1′,2′,3′,4′,10,11-Hexahydroquinin-1′-yl and -Hexahydroquinidin-1′-yl End Groups

✍ Scribed by Christian Reichardt; Jörg Stein

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 419 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199911)1999:11<2899::aid-ejoc2899>3.0.co;2-u

✦ Synopsis

Starting from the 1Ј,2Ј,3Ј,4Ј,10,11-hexahydroquinines 3a-c dihydroquinine 2a, (+)-quinidine 4a, and (+)-10,11dihydroquinidine 5a. The latter four compounds were (Schemes 1 and 3) and 1Ј,2Ј,3Ј,4Ј,10,11-hexahydroquinidine 6c (Scheme 2), we have synthesized the new chiral, hydrogenated at 70 bar and 70 °C in the presence of Raney nickel as catalyst to give the hexahydroquinine 3c and the symmetrical pentamethinium streptocyanine dyes 11a-c (Scheme 4) and 12c (Scheme 5). These products have a total hexahydroquinidine 6c, respectively. The hexahydroquinine 3c was separated into the corresponding diastereomers 3a of ten stereogenic centers in the two heterocyclic end groups, the absolute configurations of eight of which are known from and 3b by means of fractional crystallization of its salts with monochiral mandelic acid (Scheme 3). the natural starting material, i.e. (-)-quinine 1a, (-)-10,11-With the aid of modern techniques, we have recently re-[ ] Part VI: Ref. [1a] which are now widely cultivated and the extracts of which [a]