ISSN:
1434-193X
Keywords:
Cyanines
;
Dyes
;
Chirality
;
Hexahydroquinidine
;
Hexahydroquinine
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Starting from the 1′,2′,3′,4′,10,11-hexahydroquinines 3a-c (Schemes 1 and 3) and 1′,2′,3′,4′,10,11-hexahydroquinidine 6c (Scheme 2), we have synthesized the new chiral, symmetrical pentamethinium streptocyanine dyes 11a-c (Scheme 4) and 12c (Scheme 5). These products have a total of ten stereogenic centers in the two heterocyclic end groups, the absolute configurations of eight of which are known from the natural starting material, i.e. (-)-quinine 1a, (-)-10,11-dihydroquinine 2a, (+)-quinidine 4a, and (+)-10,11-dihydroquinidine 5a. The latter four compounds were hydrogenated at 70 bar and 70 °C in the presence of Raney nickel as catalyst to give the hexahydroquinine 3c and the hexahydroquinidine 6c, respectively. The hexahydroquinine 3c was separated into the corresponding diastereomers 3a and 3b by means of fractional crystallization of its salts with monochiral mandelic acid (Scheme 3).
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
