Methyl stearolate

Decarbonylation of cyclopropene acids. In a study of the synthesis of methyl sterculate (6) from methyl stearolate (1), Gensler et al.1 were unable to repeat the apparently straightforward synthesis based on addition of the Simmons-Smith reagent described in 1, 1021-1022. They were also unable to eifect addition of methylene generated by cuprous bromide decomposition of diazomethane. However, the reaction of (1) with diazoacetic ester in the presence of copper bronze, followed by hydrolysis, gives the cyclopropene diacid (2) in 70-90% yield. 

The reaction of methyl stearolate (1) with diazoacetic ester in the presence of copper bronze produces a diester, which is hydrolyzed to the diacid (2). This is converted into the diacid chloride (3). Treatment with zinc chloride or other Lewis acid effects selective decarbonylation to give the cyclopropenium ion (4). Methanol is then added to convert the acid chloride grouping into the methyl ester (5). Finally reduction with sodium borohydride gives methyl sterculate (6). 

An isolated triple bond has a similar effect on the retention characteristics of a fatty acid as three methylene-interrupted double bonds, and methyl stearolate (methyl octadec-9-ynoate) is eluted with or slightly after methyl linolenate on columns packed with DEGS [333] or PEGA [620]. Retention data on several different stationary phases have been published for the complete series of methyl octadecynoates (i.e. in positions 2 to 17) [85,323], The ECL values tend to be parallel to those of the corresponding frans-monoene isomers, but differing by 0.6 to 0.7 units on DEGS and 0.1 to 0.2 units on... 

Methyl sterculate (21) was also obtained from methyl stearolate (18 1 9a), albeit in lower yield ( 10%), by irradiation in the presence of diazomethane. ... 

Tritiation of methyl stearolate (an acetylenic fatty acid ester) was shown to yield cts- and rans-9,10-octadecenoate ester as the major radiochemical product and minor amounts of radioactive methyl stearate by addition and by substitution. 

Reaction of ethyl diazop- Cjacetate with methyl stearolate (155) produced the cycloproprenoid diacid diester 156. Removal of the cyclopropene carboxyl group was accomplished by saponification to the diacid, dehydration and decarbonylation upon treatment with HCIO4/AC2O and subsequent NaBHr reduction of the resulting cyclopro-... 

Sodium >-toluenesulfinate dihydrate, 34, 93 Sommelet reaction, 33, 93 Sorbic acid, 5-hydroxy-0-methyl, 5-lactone, 32, 57 Stannic chloride, 33, 91 Stearic acid, 34, 15 Stearolic acid, 37, 77 Stearone, 33, 84 cis-Stilbene, 33, 88 Irans-Stilbene, 33, 89... 

Nearly all methods for preparation of stearolic acid involve de-hydrohalogenation of a 9,10-dihalostearic acid, or its esters, with alcoholic potassium hydroxide the most recent method is that of Adkins and Burks.8 These methods employ drastic conditions, which result in poorer yields than those obtainable on dehydrohalogenation with sodamide.6 Methyl 9,10-dibromostearate, on dehydrobromi-nation with sodamide, yields stearolamide 6 (m.p. 82-83°) which may be hydrolyzed to stearolic acid. For preparative purposes, however, this method offers-no special advantage over that described here. 

The esters of acetylenic acids, with the exception of a,/3-unsatiU ated acids, can be converted to hydrazides. Ethyl stearolate and ethyl undecynoate readily give hydrazides, the latter in 80% yield. Esters of a,/3-acetylenic acids react with hydrazine to form pyrazolones for example, ethyl tetrolate gives 3-methyl-5-pyrazolone. ... 

Tritiated oleic acid (Kritchevsky et al., 1955) has been prepared by saponification of the glyceryl trioleate-H which was obtained by react-ing glyceryl trioleate with H2 0. Tenny and co-workers (1963) prepared H -oleic acid from stearolic acid which was obtained in turn from methyl oleate by dehydrodehalogenation. 

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