PREPARATION OF 3,4-DIHYDRO-2H-BENZOPYRAN DERIVATIVE

• Main Authors: FUJITA YOSHIJI, SHIONO MANZOU, NISHIDA TAKUJI
• Format: Patent
• Language: English
• Published: 24.11.1983
• Subjects: CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

PURPOSE:To obtain easily the titled compound useful as an intermediate for synthesizing optical active vitamin E and tocotrienol using inexpensively obtainable raw materials, by reacting hydroquinone (derivative) with a specific pyran derivative in the presence of a Lewis acid. CONSTITUTION:A compound shown by the formula I (R is H or protecting group; R is H or alkyl; R and R are R , alkoxy, or R and R are linked to form -CH=CH-CH=CH) is reacted with a 4-methyl-5,6-dihydro-2H-pyran shown by the formula II (one of X and Z is H and the other is linked to Y to form a bond) or 4-methylene-tetrahydropyran in the presence of a Lewis acid (e.g., aluminum chloride) in an amount to give 0.5-1.0 the molar quantity of the compound shown by the formula I at 0-100 deg.C, to give the desired compound shown by the formula III. USE:An organic acid ester of the desired compound is a stabilizer to the influence of light, heat and oxidizing agent for organic materials, especially synthetic resins.