Unsaturated carboxylic acids and esters

DETAILED DESCRIPTION What is claimed is: 1.
A compound of the formula: ##STR4## wherein R' is hydrogen or lower alkyl of one to five carbon atoms.
2.
A compound according to claim 1 wherein R' is hydrogen.
3.
A compound according to claim 1 wherein R' is methyl or ethyl.
4.
A compound according to claim 3 wherein R' is methyl.




Description:
This invention relates to the synthesis of the sex pheromone of the San Jose scale, Quadraspidiotus perniciosus (Comstock), and intermediates therefor.
The San Jose scale is a pest of fruit crops.
The sex pheromone is made up of the following two components in about a 1:1 ratio: ##STR1## In the practice of the above synthesis of component AI, 4-methyl-4-penten-1-ol (III) is converted to bromide (V) with bromine in the presence of triphenylphosphine and pyridine.
Alternately, 4-methyl-4-penten-1-ol is reacted with mesyl chloride and triethylamine to give the corresponding mesylate (IV), which is then reacted with sodium bromide.
The bromide (V) resulting from either of these methods is reacted with magnesium, in the presence of ether, forming a Grignard reagent (VI).
This Grignard reagent is reacted with cuprous bromide/dimethyl sulfide complex and trimethylsilyl 3-butynyl ether to make the alcohol (VII), which is treated with propionic anhydride in pyridine to yield compound AI.
Alternately, the Grignard reagent VI may be reacted with the cuprous bromide/dimethyl sulfide complex and 3-butyn-1-yl propionate, in ether, giving the compound AI.
The synthesis of component AII is outlined below: ##STR2## In the practice of the synthesis of compound AII, propiolic acid (VIII) and the bromide V are reacted, in the presence of t-butyllithium and ether, to give the carboxylic acid (IX), which is then esterified to compound X (R is lower alkyl of one to six carbon atoms).
The acetylenic ester X is methylated following the procedure of R.
J.
Anderson et al.
, J.
Am.
Chem.
Soc.
, 97, 1197 (1975) to the diene ester (XI), which is then reduced to the corresponding alcohol (XII) by reaction with diisobutyl aluminum hydride in heptane