Pyrano-flavylium compounds are flavylium derivatives with occurrence in processed foodstuffs such as wine and red fruit juices. In this work, the chemical equilibria of “bio-inspired” pyrano-3-deoxyanthocyanin dyes (4–8), presenting different substituent groups in D ring (10-methyl, 10-catechol, 10-dimethylaminophenyl, 10-carboxy) as well as in B ring (3′,4′-dihydroxy, 4′-carboxy), were studied for the first time in aqueous solutions by UV–Vis spectroscopy. The presence of a methyl group at C-10 (pigment 4) seems to stabilize the flavylium cation (AH⁺) shifting the deprotonation of 7-OH to a higher pK_a1 (pK_a1 = 5.0 ± 0.1). On the other hand, the quinoidal bases (A, A⁻) were more stabilized for the pigments which undergo the first acid-base equilibrium at C-10 substituent, as could be observed by the pK_a2 constants (pK_a2 = 8.4 ± 0.1 and pK_a2 = 8.1 ± 0.1, pigments 6 and 8, respectively).

吡喃黄酮化合物是黄酮衍生物，存在于诸如葡萄酒和红色果汁等加工食品中。在这项工作中，“生物启发式”吡喃-3-脱氧花青素染料（4-8）的化学平衡为D环（10-甲基，10-邻苯二酚，10-二甲基氨基苯基，10-羧基）具有不同的取代基。以及在B环（3'，4'-二羟基，4'-羧基）中，都是通过UV-Vis光谱法在水溶液中进行的首次研究。C-10（颜料4）上存在一个甲基似乎可以稳定黄酮阳离子（AH ⁺），从而将7-OH的去质子化转移至更高的p K _a1（p K _a1  = 5.0±0.1）。在另一方面，醌型碱基（A，A ^-）对于在C-10取代基处经历第一酸碱平衡的颜料，更稳定，这可以通过p K _a2常数（p K _a2  = 8.4±0.1和p K _a2  = 8.1±0.1，颜料6和8分别）。