Usnic acid. IV. Isoanhydromethyldihydrousnic acid was written by Takahashi, Kotaro;Miyashita, Shuichi;Ueda, Yoshie. And the article was included in Chemical & Pharmaceutical Bulletin in 1963.Recommanded Product: 2′,6′-Dihydroxy-4′-methylacetophenone This article mentions the following:
Acetylation of 30 g. methyldihydrousnic acid yielded 12 g. anhydromethyldihydrousnic acid (I) monoacetate, m. 172-3°, and from the mother liquor, after evaporation and hydrolysis of the residue, 1 g. title compound (II, R = H), m. 196°. Acetylation of 4 g. II (R = H) by warming 3 hrs. on a steam bath with 40 cc. AcOH containing 4 drops concentrated H2SO4 gave II (R = Ac), m. 142-3°, which was deacetylated by hydrolysis either with 5% NaOH at room temperature or with ice-cold H2SO4 to give II (R = H), indicating absence of any rearrangement during acetylation. Ozonolysis of II (R = Ac) in CHCl3, followed by warming 30 min. with EtOH gave 6,2,4,3-Me(HO)2AcC6HCO2H (III), m. 180° (decomposition), and 6,2,3,4-Me(HO)Ac(AcO)C6HCO2Et (IV), m. 115-16°. Vacuum distillation of III at 180-200° gave the known 4,2,6-Me(HO)2C6H2Ac (V), m. 146°, and deacetylation of IV by heating 1 hr. with 5% NaOH on a steam bath and acidifying gave the known 6,3,2,4-MeAc(HO)2C6HCO2Et (VI), m. 89-90°, identical with the product of ethylation of 6,3,2,4MeAc(HO)2C6HCO2H with diazoethane in Et2O. These results showed that a γ-orcacetophenone ring was present in II as well as in I. Both infrared and ultraviolet absorption curves were shown for I and II (R = H). Refluxing 1 g. II (R = H) 5 hrs. on a steam bath with HONH2.HCl and AcONa in EtOH yielded 1 g. dioxime monoanhydride (VII), m. 280° (decomposition), which (0.5 g.) was oxidized with H2O2 at 80-90° to yield 50 mg. 4-carboxy-α,α,3-trimethyl-5-isoxazoleacetic acid, m. 217°, the same compound previously similarly derived from I. This indicated that the relative positions of the Ac, enolic HO, and gem-di-Me groups were the same in the A rings of I and II. However, the difference in the conjugated systems of the A rings (as shown in formulas I and II) was confirmed by the shift of 35 mμ in the maximum at 237 mμ of II to that at 272 mμ of I. All these results established the assigned formula for II, which was further confirmed by the nuclear magnetic resonance spectrum (curve shown). As previously suggested for the mechanism of the preparation of I, the simultaneous formation of II would likewise involve the fission of the C-O-C bond in the furan ring and the removal of the newly-formed HO group in the B ring. Then the mode of reformation of the C-O-C linkage would determine whether I or II would result from the following dienonephenol rearrangement. Ultraviolet or infrared absorption spectra (in addition to the curves for I and II) were used to support the structures of III-VII. In the experiment, the researchers used many compounds, for example, 2′,6′-Dihydroxy-4′-methylacetophenone (cas: 1634-34-0Recommanded Product: 2′,6′-Dihydroxy-4′-methylacetophenone).
2′,6′-Dihydroxy-4′-methylacetophenone (cas: 1634-34-0) belongs to alcohols. Because alcohols are easily synthesized and easily transformed into other compounds, they serve as important intermediates in organic synthesis. Alcohols may be oxidized to give ketones, aldehydes, and carboxylic acids. These functional groups are useful for further reactions. Oxidation of organic compounds generally increases the number of bonds from carbon to oxygen (or another electronegative element, such as a halogen), and it may decrease the number of bonds to hydrogen.Recommanded Product: 2′,6′-Dihydroxy-4′-methylacetophenone
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts