[CONTRIBUTION FROM THE SCHOOL OF CHEMISTRY OF THE UNIVERSITY OF MINNESOTA]
T H E CHEMISTRY OF VITAMIN E. IX. PREPARATION OF LONG CHAIN HALIDES AND KETONES CONTAINING ISOPENTANE U N I T S LEE IRVIN SMITH, HERBERT E. UNGNADE, F. L. AUSTIN, PRICHARD, AND J. W. OPIE
w.w.
Received March Si, 1959
In connection with several projected syntheses of tocopherols, their coumaran isomers and lower “prenologs”2 halides of types I and 11, as well as ketones of types 111, were required (n = 1 or 2) (CHI)zCHCHzCHz ICHzCH(CH3)CHzCHz ],X (1) (CH3)zCHCHzCHz ICHzCH(CH3)CHzCHz],CHzX (11) (CHs) zCHCHzCHz [CHzCH(CH3)CHzCHz],CHzCOCH3 (III) This paper contains a description of the synthesis of such compounds, together with some observations on the cleavage of aliphatic ethers, formation of long-chain halides, alkylations of acetoacetic ester and acetonedicarboxylic ester with these halides, and hydrolysis of the resulting keto esters to ketones. There are two readily available substances, both alcohols, which contain a chain composed of two isoprene units, geraniol (IV) and citronellol (V), and
(C&)zC=CHCH&H&(CHa)=CHCH2OH (CH3) ZC=CHCH~CH~CH(CH,)CH~CH~OH
(IV)
(VI our syntheses therefore started with these substances. The general plan is shown in the following diagram:
IT}+ (CH3)2CHCH2CH2CH2CH(CH3)CH2CH20H (VI)
(1)
VI + I(n = 1, X = Br or Cl)
(2)
I
---f
2
RCH
