Methylheptanoic Acid

Methylheptanoic acid, 41, 60 N-Methylheptylamine, 44, 74 N-Methylhexylamine, 44, 74 Methylhydrazinium hydrogen sulfate, 43, 2... 

A solution of 40 g. (0.2 mole) of sec-butyl 3-methylheptanoate in 100 ml. of ethanol containing 18.5 g. (0.3 mole) of potassium hydroxide and 20 ml. of water is heated under reflux for 30 minutes (Notes 7 and 8). The cooled solution is diluted with 200 ml. of water and acidified by the addition of 60 ml. of concentrated hydrochloric acid. The organic acid is extracted with three 100-ml. portions of 1 1 benzene-ether, and the combined benzene-ether extracts are washed with 50 ml. of saturated sodium chloride solution. The resulting solution is filtered by gravity through a bed of anhydrous magnesium sulfate. After removal of solvents by distillation, 26-27 g. (90-94%) of 3-methylheptanoic acid, b.p. 116-117710 mm., d 1.4242, is obtained by distillation in a modified Claisen flask (Note 9). 

Methylheptanoic acid has been prepared by mixed electrolysis of / -methylglutaric acid monomethyl ester and butyric acid, followed by saponification of the methyl ester,10 and by the mal-onic ester synthesis from 2-bromohexane.11 The present method7 has the advantage of avoiding the use of secondary bromides, which are often difficult to secure entirely pure.12... 

Ethyl crotonate, preparation of 3-methylheptanoic acid from, 41, 63... 

B. 3-Methylheptanoic acid. In a 2-1. three-necked flask fitted with a mercury-sealed stirrer, a reflux condenser carrying a calcium chloride tube, and a dropping funnel are placed 25.0 g. (1.04 g. atoms) of magnesium turnings. The flask is heated to about 100° for a few minutes and then cooled to room temperature. A solution of 178 g. (1.30 moles) of -butyl bromide in 300 ml. of dry ether is prepared and of this solution about 10 ml., together with 30 ml. of dry ether, is run into the flask. The reaction is started by heating to reflux for a few seconds, the stirrer is started, and the remainder of the bromide solution is added at such a rate as to maintain constant reflux (about 1 hour). 

Furthermore, O Shea and colleagues reported the enan-tioselective carbolithiation of ori/to-aminostyrenes as summarized in Scheme 4 [12, 13]. The chiral intermediate 13 (equation 1) has the S-configuration based on the generation of known (5)-3-methylheptanoic acid from 14. Quenching 13 with electrophiles furnished 15 in modest to good yields and in very good enantiorichments (equation 2) [12]. Electrophiles included DMF, PhCN, y-butyrolactone, A-methoxy-A-methylacetamide, and 2,2-diethoxypropionitrile. Carbon dioxide afforded the expected oxindole [13]. Debenzylation was effected with Li in NHj (equation 3) [13]. 

Heptanol-2 17 (29) 2-Methylheptanoic acid-2 28 (48) 3-Methylheptanoic acid-3 9 (3) Octanoic acid-4 23 (1) Octanoic acid-3 8 (1) Octanoic acid-2... 

For the preparation of prostacyclin derivative ([3- " C]nonyl)SM-10902 1821. halo-decarboxylation of (35)-3-methylheptanoic acid 1781 gave key intermediate 79. Grignard reagent preparation, carboxylation with " COj, esterification and subsequent reaction of the resulting ethyl ester with lithiated dimethyl methylphosphonate afforded ketophos-phonate SI in 70% overall radiochemical yield. Homer—Wadsworth—Emmons reaction with the corresponding aldehyde derivative and reduction of the resulting a,/3-unsaturated ketone converted 81 into 82". ... 

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