Methyl hydrogen sebacate

An excellent synthesis of myristic acid is thus achieved from readily accessible starting materials. An alternative synthesis of myristic acid utilises hexanoic acid (M-caproic acid n-hexoic acid) (X) (2 mols) and methyl hydrogen sebacate (XI) (1 mol) the products, after hydrolysis, are Ji-decane (XII), myristic acid (XIII) and hexadecane-1 16-dlcarboxylic acid (XIV) ... 

Myristic acid from hexanoic acid and methyl hydrogen sebacate). Dissolve 23 -2 g. of redistilled hexanoic acid (re caproic acid), b.p. 204-6-205-5°/760 mm., and 21-6 g. of methyl hydrogen sebacate in 200 ml. of absolute methanol to which 0 13 g. of sodium has been added. Electrolyse at 2 0 amps., whilst maintaining the temperature between 30° and 40°, until the pH is about 8 0 (ca. 6 hours). Neutralise the contents of the electrolysis cell with a little acetic acid and distil off the methyl alcohol on a water bath. Dissolve the residue in 200 ml. of ether, wash with three 50 ml. portions of saturated sodium bicarbonate solution, once with water, dry with anhydrous magnesium sulphate, and distil with the aid of a fractionating column (see under Methyl hydrogen adipate). Collect the re-decane at 60°/10 mm. (3 0 g.), the methyl myristate at 158-160°/ 10 mm. (12 5g.) and dimethyl hexadecane-1 16-dicarboxylate at 215-230°/ 7 mm. (1 -5 g.)... 

The methyl hydrogen sebacate used by the submitters was prepared by the method described by Pattison and co-workers,2... 

To 500 ml. of absolute methanol (Note 1) in a 1-1. electrolytic (tall form) beaker is added 1.1 g. (0.05 g. atom) of clean sodium metal. After solution of the sodium, 216 g. (1.0 mole) of methyl hydrogen sebacate (Note 2) is dissolved in the sodium methoxide solution. A magnetic stirring bar is placed in the beaker which is then fitted with a large neoprene stopper (Note 3) holding a platinum sheet anode, 12 cm.2 in area and two platinum sheet cathodes, approximately 5.3 cm.2 in area, spaced equidistantly on either side of the anode at a distance of approximately 1.5 cm. (Note 4). The stopper is also provided with a stoppered entry tube and an efficient reflux condenser (Note 5). 

Hexadecane-1 16-dicarboxylie acid. Dissolve 31 5 g. of methyl hydrogen sebacate in 140 ml. of absolute methanol to which 0-4 g. of sodium lias been added. Electrolyse at 2 0 amps, until the pH of the electrolyte is 7 8-8 0 (3-5-4 hours). Work up as described for Sebacic acid. Upon distillation, an unsaturated ester passes over at 111-113°/ 20 mm. (4-6 g.), followed by dimethyl hexadecane-1 16-dicarboxylate at 212-219°/4 mm. (mainly at 214-215°/4 mm.), m.p. 56° (16-5 g.). 

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... 

Methyl hydrogen sebacate (b.p. 168-170°/3 mm.) was prepared by the checkers in yields of 52-61% from sebacic acid and methanol by the procedure described for the ethyl analog.1 The ethyl ester can be used to obtain ethyl sebacamate. The preparation of the acid chloride from ethyl hydrogen sebacate is mentioned in Note 12, page 21. 

Simple anodic coupling by electrolysis in anhydrous methanolic solution (containing a little sodium methoxide) of methyl hydrogen adipate (Expt 5.147) gives dimethyl sebacate methyl hydrogen sebacate (Expt 5.147) in turn yields dimethyl octadecanedioate (Expt 5.131, cognate preparations). 

Two alternative syntheses of methyl myristate, and thence myristic acid, are described (Expt 5.131). In Method A hexanoic acid (2mol) is coupled with methyl hydrogen sebacate (1 mol), the products being methyl myristate, decane and dimethyl octadecanedioate. 

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