US Patent 4,000,187
United States Patent and Trademark Office
University of Iowa Research Foundation (Iowa City, IA, US)
Polymers containing recurring quinoline or anthrazoline groups which are reaction products of aromatic amino carbonyl compounds containing two sets of ortho-amino aldehyde or ortho-amino ketone functions attached to the aromatic nucleus having the general structure: ##STR1## (wherein R is hydrogen, or aryl and the Ar's are aryl groups) with methylene ketones containing two ketone functions having a methylene group adjacent to each ketone and having the general structure: ##STR2## (wherein R = hydrogen or aryl and R' = aryl and the Ar's are aryl groups) are described. According to the above, R from both the aromatic amino carbonyl and the aromatic methylene ketone could be hydrogen when producing a polymer, but the polymer in which both R's are hydrogen is excluded from this invention.
Stille, John K. Quinoline and anthrazoline polymers. US Patent 4,000,187 filed April 11, 1972 and issued December 28, 1976. https://ir.uiowa.edu/patents/7