| abstract |
1,156,119. Pyran derivatives; ionone derivatives. R. J. REYNOLD TOBACCO CO. 2 Sept., 1966 [8 Nov., 1965 (2)], No. 38755/68. Divided out of 1,154,089. Heading C2C. [Also in Division A2] 2 - Acetonyl - 4 - methyltetrahydropyran is made by reacting an absolute ether solution of #-methyl-#-valerolactone with lithium aluminium hydride in ether to give 2-hydroxy-4- methyltetrahydropyran, and subsequently hydrolysing with water. 2,3,6,7,8,8a - Hexahydro- 7 - oxo - 2,5,5,8a - tetramethyl - 1 - benzopyran is made by reacting α-ionone with t-butyl chromate dissolved in a mixture of carbon tetrachloride, t-butyl alcohol, acetic acid and acetic anhydride, chromatographically extracting the 5-oxo-α-ionone formed and after recrystallization re-arranging it by standing in 1: 1 aqueous/methanolic potassium hydroxide to produce the dione and treating this dione with sodium borohydride in ethanol and subsequently acidifying to give the keto-alcohol and cyclizing the keto alcohol by reflux in benzene containing p-toluenesulphonic acid. |