Laser Dyes, V: Synthesis of Plane Rigidized Heptamethinecyanine Dyes.

摘要

1,4,5,8,9,10-Hexahydro-2,7-dimethoxyanthracine (4) was synthesized from 2,7-dihydroxyanthraquinone (1) in a three-step synthesis. The individual synthesis steps can be performed in various ways. The pathway described here permits the convenient access to the product, gives the highest total yields and is also accessible on a larger scale (0.1 mol). The initiating methylation of 1 with dimethyl sulfate/KOH leads to the bismethyl ether (2) from which 4 can be synthesized by double reduction. 2 is first reduced with zinc in dilute ammonia to form an anthracene derivative which is then converted to the desired hydroanthracene 4 by Birch reduction with lithium. The total yield in this process is 76%. 12 refs., 1 fig., 2 tabs. (ERA citation 13:040557)