Methyl 10-undecenoate Research Articles

Synthesis ofZ-11-octadecenal, the sex pheromone of the wax moth

A new synthesis ofZ-11-octadecenal, the sex pheromone of the wax mothAchroia grisella starting from methyl 10-undecenoate is elaborated.

Effect of carboxylic acids on the metathesis of methyl 10-undecenoate

The metathesis of esters of unsaturated carboxylic acids catalyzed by the WCl 6/Me 4Sn system is influenced by the presence of free acids. The extent of their effect depends on how they are delivered into the reaction mixture. If the acid is allowed to react with WCl 6 (either free or as an ad-mixture to the ester) before dosing Me 4Sn, the equivalent part of WCl 6 is converted rapidly to WOCl 4 and the activity of the catalyst is not affected. An excess of the acid over WCl 6, however, leads to carboxylation of WOCl 4 followed by the formation of WO 2Cl 2, and to loss of catalytic activity. Reaction of the acid with active centres already formed results in their deactivation.

The UV-VIS spectroscopic study of the interaction between WCl6 and esters of carboxylic acids

The reaction of WCl6 with methyl 10-undecenoate and methyl palmitate has been studied. The rate constant of the first step of the reaction has been established and compared with that of the WCl6+(CH3)4Sn reaction. On the basis of this comparison the influence of the reaction of WCl6 + ester on the ester metathesis is discussed.

Interactions of tungsten hexachloride with esters of carboxylic acids

The interactions of tungsten chlorides and oxychlorides with methyl 10-undecenoate, methyl palmitate and methyl acetate, respectively, have been investigated by UV-VIS, IR and EPR spectroscopic methods. The primary complex formed by coordination of the carbonyl group to WCl6 is converted successively to an analogical, very stable complex WOCl4.ester under the simultaneous formation of acyl chloride and methyl chloride. In the case of methyl undecenoate, the coordination reaction is accompanied by a partial reduction of WCl6 to WCl5. The latter reacts with the ester in excess to give a complex characterized by a broad EPR single line at g = 1.767 (ΔH = 7.8 mT). At higher ester-to-tungsten molar ratios, this complex undergoes deeper reduction to products containing tungsten in a lower oxidation state, and competitively, a parallel oxygen abstraction reaction yielding WOCl3, acyl chloride and methyl chloride. The participation of these reactions in the formation of active WCl6-based catalysts for methathesis of unsaturated esters is discussed.

Preparation of terminal alkenic esters by an oxidative radical reaction

A general method is described for the conversion of(mono)alkenic esters with the double bond at the n th C atom to terminal alkenic esters of (n−1) C atoms in length, with the double bond at n−2. Ozonolysis, either in methanol or in light petroleum, is followed by reaction with a mixture of ferrous and cupric salts. Methyl 10-undecenoate, methyl oleate (methyl (Z)-9-octadecenoate) and methyl erucate (methyl (Z)-13-docosenoate) were converted to methyl 8-nonenoate, methyl 7-octenoate and methyl 11-dodecenoate respectively. An improved preparation of 5-hexenoic acid is also described.

Effect of reaction conditions on the activity of the WCl6 + (CH3)4Sn catalytic system in the metathesis of methyl 10-undecenoate

In contrast to published data, metathesis of methyl 10-undecenoate is found to proceed with a good yield even if the ester is present in a high excess with respect to the catalyst, if the former is first reacted with WCl6 to form a complex (owing to which the reaction mixture acquires red colour), and only then the metathesis is started by adding (CH3)4Sn. Moreover, satisfactory degrees of conversion are only attained if the catalyst concentration is low enough so that the deactivation of the active centres is slowed down.

Metathesis of methyl 10-undecenoate

The metathesis of methyl 10-undecenoate was studied using the WCl6 + (CH3)4Sn catalyst system. The rate of metathesis and the maximum degree of conversion are affected markedly by the reactions of the ester, and of the other oxygen compounds if present, with tungsten hexachloride. Introduction of an oxygen ligand to the central tungsten atom of the active centre increases the reactivity and stability of the latter, thus affecting positively the initial rate of the metathesis reaction. At the same time, however, the rate of the catalyst deactivation increasing concentration of the ester, whereupon the degree of the conversion decreases. As a result of competition of the two effects, a maximum appears in the dependence of the amount of the ester reacted on the ester-to-tungsten hexachloride ratio.

Metathesis reactions of unsaturated esters catalyzed by homogenous tungsten complexes. Syntheses of civetone and macrolides

The metathesis reactions of methyl 10-undecenoate, methyl oleate and oleyl acetate have been carried out using WCl 6 and WOCl 4 as primarycatalysts and SnMe 4, PbMe 4, Cp 2TiMe 2, and Cp 2ZrMe 2 as cocatalysts. The catalyst system WOCl 4/Cp 2TiMe 2 was found to be very active for the metathesis of the unsaturated esters and is somewhat better than the system WCl 6/SnMe 4. Diethyl 9-octadecene-1,18-dioate, obtained by the metathesis of ethyl oleate, was subjected to the Dieckmann cyclization. The cyclized product was decarboxylated to give civetone as a mixture of the cis and trans isomers. Preliminary studies of macrolide synthesis by the intramolecular metathesis of oleyl oleate and 10-undecenyl 10-undecenoate to afford 9-octadecen-18-olide and 10-eicosen-20-olide, respectively, have been carried out.

The photochemistry of α-oximino ketones: 2-Oximinocyclododecanone

Irradiation of (E)-2-oximinocyclododecanone ( 12) in methanol with a medium pressure mercury lamp gives (Z)-2-oximinocyclododecanone ( 13). 12-hydroxybicyclo[8.2.0]dodecan-11-one oxime ( 14), (2-oxocyclodecane) acetonitrile (17), and methyl 10-undecenoate ( 18). The nitrile 17 has been shown to be formed from the oxime 14 on irradiation of the latter is methanol or on treatment with acetic anhydride in pyridine. It is proposed that the ester 18 arises, like oxime 14, via γ- H-abstraction by the O atom of the CO group of the α-oximino ketone 12, and that the primary photochemical processes under the conditions used are limited to geometrical isomerization about the CN bond and such γ- H-abstraction.

DISPROPORTIONATION OF THE UNSATURATED ESTERS

Abstract The disproportionation reactions of the unsaturated esters such as ethyl 3-butenoate, methyl 10-undecenoate, methyl oleate and 9-octadecenyl acetate were carried out using alkylborane-WCl6, -Mo(OEt)2Cl3 and various other catalysts. Both Et3B-WCl6 and Et3B-Mo(OEt)2Cl3 were found to be the effective catalysts for the above reactions.

Influence of Chemical Structures in Sulfurized Fats on Antiwear Behavior

Sulfurized methyl 10-undecenoate was used as the substance typifying sulfurized fatty extreme-pressure lubricant additives. The characteristic chemical structures in sulfurized methyl un-decenoate are sulfur-bridged long-chain di-esters, of which 1,20-dicarbomelhoxy-9,12-dimethyl-10,11 -dithiaeicosane is an example. The antiwear performance of this dithio-ester with respect to hardened AISI1095 steel in a pin-and-disk apparatus was indistinguishable from that of sulfurized methyl undecenoate. Esters such as methyl laurate and 1,18-dicarbomethoxyocta-decane did not show the antiwear behavior typical of sulfurized methyl undecenoate. Organic sulfides—-di-n-octyl monosulfide, di-n-octyl disulfide, di-n-octyl tetrasulfide, di-sec-octyl disulfide, d-t-octyl disulfide—behaved much differently than sulfurized methyl undecenoate. A mixture of methyl laurate and di-sec-octyl disulfide showed the same kind of antiwear behavior as sulfurized methyl undecenoate.

Preparation of 15-hydroxypentadecanoic acid by means of condensation reaction via β-ketosulfoxide

Basic condensation of 1,12-dodecanolide with methylsulflnylcarbanion (DMSO−) gives a β-keto-sulfoxide 2 which is ethoxycarbonylmethylated and the product is converted to 15-hydroxypentadecanoic acid (6) in a 46% overall yield based on the lactone. Another β-ketosulfoxide 9 is prepared by condensation of methyl 10-undecenoate with DMSO− and is subjected to the Michael condensation with methyl acrylate. Treatment of the adduct gives 14-pentadecenoic acid (13) in a 38% overall yield based on the undecenoate.

Reactions of Methyl 10-Undecenoate and Methyl Oleate with Selenium Dioxide in Acetic Acid

酢酸溶媒中10-ウンデセン酸メチルと二酸化セレン(モル比2:1)を115℃ で空気を吹き込みながら5時間反応させた。粗生成物をケン化し,メチルエステルとしたのち,シリカカラムクロマトグラフィーで分別し,11-オキシ-9-ウンデセン酸メチルを17.0%,ビス(2-オキシ-10-メトキシカルボニルデシル)セレニドを52.2%,セレンを含有した重合物18,6%を得た。同様の反応条件でオシイン酸メチルと二酸化セレン(モル比1：1)を反応させて得た粗生成物をシリカカラムクロマトグラフィーで分離した。アセトキシオクタデセン酸メチルを9.2%,アセトキシセレノキソオクタデカン酸メチルに相当すると思われるものを39.8%,ビス[2-アセトキシ-1-(7-メトキシカルボニルヘプチル)デシル]ジセレニド,および,ビス(2-アセトキシ-9-メトキシカルボニル-1-オクチルノニル)ジセレニドと考えられるもの34.0%を得た。オレイン酸メチルから得られたセレン付加体が10-ウンデセソ酸メチルの場合のセレン付加体と構造様式の異なるのは両者のこ重結合における立体障害の差異によるものと思われる。