1) Pyran is not aromatic, but the phrylium ion is.

2) Methods To establish the effect of Benzo pyran derivatives on rats by grouping randomly and giving medicine.

3) Pyran Derivatives is widespread in erigeron, And the treatment showed a strong stroke, And the regulation of blood pressure, the protection effect For ischemia-reperfusion injury.

4) The cholesteryl-based pyran dye has a structure shown as the formula (I).

5) With 2 - phenyl benzo - pyran structure, also known as anthocyanin pigments, the base element for the flower pigments, 2 - phenyl - benzo - pyrone, also known as anthoxanthin class.

6) Two new derivatives of 4 - dicyanomethylene - 2 , 6 - dimethyl - 4 H - pyran and the corresponding poly ( amic acid ) were synthesized and characterized.

7) This paper reports firstly the compounds is synthesized through acetylation and closing ring. And the method of inducting pyran ring to benzene is solved.

8) Under the acid free condition, 3 acetyl 2 hydroxy 6 methyl pyran 4 one (8) was obtained and its structure was confirmed by X ray diffraction analysis.

9) The HMCM-22 was found to be highly active for the hydrolysis of pyran with high yield and stability.