Dihydroxystearic acid

N-Methyllauramide, N-methyhnyristamide, and N-methyl-pelargonamide can be prepared in 95-98% yield by adaptation of the method used by Roe, Scanlan, and Swern for the preparation of amides of oleic and 9,10-dihydroxystearic acids. 

FIGURE 13 Cumulative release of -nitroacetanilide (PNAC) from polyester discs prepai ed from 3,9-bis(ethylidene-2,4,8,10-tetraoxas-piro[5,5]undecane) and a 60 10 30 mole ratio of trans-cyclohexane dimethanol, 1,6-hexanediol, and triethylene glycol at pH 7.4 and 37 C. PNAC content 2 wt% (o) 0 mol%, ( ) 0.25 mol%, ( ) 0.50 mol% 9,10-dihydroxystearic acid. (From Ref. 23.)... 

FIGURE 20 Daily rabbit blood plasma levels of levonorgestrel from a crosslinked polyn)er prepared from a 3,9-bis(ethylidene-2,4,8,10-tetraoxaspiro[ 5,5 Jundecane) / 3-methyl-l, 5-pentanediol prepolymer crosslinked with 1,2,6-hexane triol. Prepolymer contains 1 mol% copolymerized 9,10-dihydroxystearic acid. Polymer rods, 2.4 x 20 mm, containing 30 wt% levonorgestrel and 7.1 mol% Mg(OH)2- Devices implanted subcutaneously in rabbits, (o) 1 device/rabbit, (a) 2 devices/rabbit. 

The checkers used commercial u.s.p. oleic acid, which has an iodine number of about 60-70 and contains 65-75% oleic acid. The submitters report that, if highly purified oleic acid is used, the yield of fairly pure 9,10-dihydroxystearic acid is almost quantitative, but the purification procedure for oleic acid [Biochem. Preparations, 2, 100 (1952)] is more lengthy and inconvenient than the purification of the hydroxylation product. The over-all yield is approximately the same in either case. 

Oxidation of 9,10-Dihydroxystearic Acid.116 The Use of Aqueous Ethanol as the Solvent. A solution of 6 g. of potassium periodate in 300 cc. of N sulfuric add at 20° is added rapidly to a solution of 8 g. of 9,10-dihydroxystearic add (m.p. 132°) in 400 cc. of alcohol at 40°. After ten minutes the clear solution is cooled to 15° and diluted with suffident water to dissolve the predpitated potassium sulfate. Extraction with ether gives an oily product, which is submitted to steam distillation. Extraction of the distillate with ether yields 3.2 g., or 89%, of pure pelargonaldehyde as a colorless oil boiling at 76-77° (11 mm.). 

TNBSA followed by hydrolysis gives ihreo- and eryr/iro-9,10-dihydroxystearic acids, respectively, in yields of 65-70%. Thu.s clean inversion occurs when DMSO reacts with the oxide ring. 

Hydroxy and Epoxy Acid Group Although a number of oils contain acids with hydroxy, epoxy, or oxo (keto) functions, only one is readily available. Castor oil contains over 90% of ricinoleic acid (12-hydroxyoleic acid) and about 1% of 9,10-dihydroxystearic acid (section 5.1). 

Reaction of a triol such as 1,2,6-hexanetriol with a DETOU prepolymer permits the formation of a cross-linked network. Rod-shape polymer systems (2.4 mm in diameter) were fabricated containing 30wt% levonor-gestrel and 7 wt%o micronized Mg(OH)2 as a stabilizer. These devices contained 1 wt% 9,10-dihydroxystearic acid to modify polymer erosion rate. SEM photomicrographs of the rods show evidence of surface... 

Roe, E.T. Scanlan, J.T. Swern, D. Fatty Acid Amides. I. Preparation of Amides of Oleic and the 9,10-Dihydroxystearic Acids Journal of the American Chemical Society (1949) 71 2215-2218. 

Dihydroxystearic acids, 193 Diimide, 154-155, 535 Diiminosuccinonitrile(DiSN), 155-157 fem-Dhodoalkanes, 260 3,7-Diiodo-frans, irans-2,6-octadiene-1 -ol,... 

Cleavage of a water-insoluble diol is exemplified by the oxidation of erylhro-9,10-dihydroxystearic acid (4, m.p. 132°). A solution of 6 g. of potassium periodate... 

Purification. Brown et aV cite references to four methods of purification of oleic acid. Swern s group describe a procedure involving low-temperature crystallization, distillation, and distillation of the ester. However, in a procedure for the preparation of rhreo-9,10-dihydroxystearic acid by performic acid hydroxylation of oleic acid, Swem et al. state that their method of purifying oleic acid is lengthier and less convenient than purification of the dihydroxy acid. 

The hydrolysis rate of poly (ortho esters) can be further manipulated by a combination of hydrophilicity and the use of diols that contain a pendant carboxylic acid, such as 9,10-dihydroxystearic acid [36]. Figure 16 shows the release of a marker compound p-nitroacetanilide from a hydrophobic matrix prepared from a 60/40 mole ratio of frans-cyclohexanedimethanol and 1,6-hexanediol containing varying amounts of 9,10-dihydroxystearic acid. While there is a noticeable effect, it is relatively minor. However, when the hydrophilicity of the matrix is increased by using a 60/10/30 mole ratio of trans-cyclohexanedimethanol, 1,6-hexanediol and triethylene glycol, the effect of 9,10-dihydroxystearic acid is greatly magnified, as shown in Fig. 17. 

Fig. 16. Release of p-nitroacetanilide (PNAC) as a function of time from polymer disks prepared from 3,9-bis (ethylidene-2,4,8,10-tetraoxaspiro [5,5] undecane) and a 60/40 mol ratio of transcyclohexane dimethanol and 1,6-hexanediol at pH 7.4 and 37 °C. Polymer contains copolymerized 9,10-dihydroxystearic acid (DHSA) and 2 wt% PNAC.(D) no DHSA,(O)0.25 mol% DHSA, ( ) 0.50 mol% DHSA [36]. Reprinted with permission...

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