Crossword-Solution: CARBOXYLIC 10 letters, 1 clue 🏆 scrabble score: 26

Their basic idea was the absence of carboxylic groups in tannin, and that hence the total gallic acid must be present in ester form.

LUTEIC ACID (Luteo Saure, pentoxybiphenylmethylolide carboxylic acid),C_14H_8O_9, occurs, in addition to ellagic acid, in myrabolams-- [Footnote: _Ber_., 1909, 42, 353.] ----CO.O---- ^ ---------- ^ OH | | | | HO V OH HOOC V OH OH OH It is obtained by extracting myrabolams for one hour and a half, under reflux condenser, with pyridine, filtering and adding twice the volume of water to the filtrate and boiling till complete solution is obtained.

Digallic acid 2.1042 80.16 19.84 Leucodigallic acid 2.0041 1.94 98.06 With the introduction of the carboxylic group the tendency of condensation to diphenylmethane derivatives is lessened; by protocatechuic acid the tendency is nil.

Tollens points out that the results of empirical analysis are inconclusive; and that from the acid reactions of these products and their combination with bases, carboxylic groups are present, though probably in anhydride or ester form.

The diazo cyanides, C_6H_5N_2·CN, and carboxylic acids, C_6H_5·N_2·COOH, may also be considered as mixed azo derivatives.