Claims
- 1. A process for preparing a triconjugated dienone defined according to the structure: ##STR94## wherein R.sub.1 is C.sub.1 -C.sub.8 alkyl, phenyl or phenyl methyl and R.sub.2 is hydrogen or C.sub.1 -C.sub.5 alkyl; and wherein the wavy lines represent the "cis" and "trans" juxtaposition of the vinyl, methyl, acyl and R.sub.2 moieties about one or both of the carbon-carbon double bonds comprising the steps of:
- (i) reacting an acyl halide having the structure: ##STR95## wherein X represents chloro with an ester having the structure: ##STR96## in the presence of an aluminum chloride catalyst and a methylene dichloride solvent in order to form the compound having the structure: ##STR97## wherein R.sub.3 is C.sub.1 -C.sub.5 alkyl, the mole ratio of aluminum trichloride:ester defined according to the structure: ##STR98## acyl halide being about 2:1:1, the reaction temperature being in the range of from about -30.degree. C. up to about +20.degree. C.; then
- (ii) dehydrohalogenating the compound having the structure: ##STR99## with a dehydrohalogenation agent comprising an alkali metal carbonate and dimethylformamide to form a compound defined according to the structure: ##STR100## wherein one of the dashed lines is a carbon-carbon double bond and the other of the dashed lines is a carbon-carbon single bond; and wherein X represents chloro, bromo or iodo, the temperature of reaction being between about 80.degree. C. and 100.degree. C., the mole ratio of alkali metal carbonate:haloester defined according to the structure: ##STR101## being from about 2:1 down to about 1:1; the concentration of the haloester reactant in the dimethylformamide solvent varying from about 0.1 moles per liter up to about 1.5 moles per liter; and then
- (iii) dehydroacyloxylating the resulting compound having the structure: ##STR102## with an alkali metal carbonate and dimethylformamide at a temperature of from about 100.degree. C. up to about 150.degree. C. thereby forming the compound having the structure: ##STR103##
- 2. The process of claim 1 wherein R.sub.1 is 2-methyl-1-propyl; X is chloro; R.sub.2 is hydrogen; and R.sub.3 is methyl.
Parent Case Info
This is a division of application Ser. No. 551,480, filed Nov. 14, 1983, which, in turn, is a division of application Ser. No. 431,268, filed Sept. 30, 1982, now U.S. Pat. No. 4,451,392 issued May 29, 1984.
US Referenced Citations (4)
Non-Patent Literature Citations (4)
Entry |
Adams et al, J. Chem. Soc., Perkin I, 1975, pp. 1741-1743. |
Thomas, Anhydrous Aluminum Chloride in Organic Chemistry, pp. 752-757, (1941). |
Young, "Protective Groups in Organic Chemistry", pp. 309-321, (1973). |
Fieser et al, Reagents for Organic Synthesis, vol. 4, pp. 414-415, (1978). |
Divisions (2)
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Number |
Date |
Country |
Parent |
551480 |
Nov 1983 |
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Parent |
431268 |
Sep 1982 |
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