15-Hydroxypentadecanoic acid

Intramolecular lactonization can also be carried out with DCCI and DMAP. As with most other macrolactonizations, the reactions must be carried out in rather dilute solution to promote the intramolecular cyclization in competition with inter-molecular reaction, which leads to dimers or higher oligomers. A study with 15-hydroxypentadecanoic acid demonstrated that a proton source is beneficial under these conditions and found the hydrochloride of DMAP to be convenient.130... 

Production. The main industrial syntheses start from compounds produced from cyclododecatriene either by ring expansion of cyclododecanone or by depolymerization of polyesters of 15-hydroxypentadecanoic acid (from 1,12-dodecanediol). 

Preparation from Polyesters of 15-Hydroxypentadecanoic Acid. In a Japanese process, the required a -hydroxy acid is prepared from 1,12-dodecanediol in... 

The polyester of 15-hydroxypentadecanoic acid is prepared by customary methods and is cleaved under high vacuum in the presence of transesterification catalysts. 

Another effect of zeolite pore architecture on esterification is found in the lactonization of 15-hydroxypentadecanoic acid. With dissolved acid catalysts or with amorphous Si02-Al203, dimerization or polymerization are the dominant reactions, but when the reactant is adsorbed within the pores of a dealuminated HY zeolite, only the pentadecanolide is obtained (8) ... 

The disulfide was used to effect lactonization of 15-hydroxypentadecanoic acid. Under conditions of high dilution the yield of pentadecanolide was 88%... 

PPL catalyzed the polymerization of methyl esters of 5-hydroxypentanoic and 6-hydroxyhexanoic acids.149 In the polymerization of the latter in hexane at 69 °C for more than 50 days, the polymer with DP up to 100 was formed. Relationships between solvent type and polymerization behaviors were systematically investigated hydrophobic solvents such as hydrocarbons and diisopropyl ether were suitable for the enzymatic production of high molecular weight polymer. Pseudomonas sp. lipase catalyzed the polymerization of ethyl esters of 3- and 4-hydroxybu-tyric acids, 5- and 6-hydroxyhexanoic acids, 5-hy-droxydodecanoic acid, and 15-hydroxypentadecanoic acid.157 Oxyacid vinyl esters were demonstrated as new monomers for polyester production under mild reaction conditions, yielding the corresponding polyesters with A/n of several thousands.276... 

Cyclization. A macrocyclic lactone has been acquired (with yields up to 32%) from 15-hydroxypentadecanoic acid by exposure to dealuminated HY zeolite. Five-and six-merhbered heterocycles can be synthesized from diols with a modified ZSM-5 zeolite (from 18-30 mesh HZSM-5 and Cr20j, and activated at 420°C for 4 h). For example, IV-methylpyrrolidine is obtained in 64% yield from 1,4-butanediol and methylamine. ... 

One example of lactonization promoted by Ag was reported. Addition of 1 eq. of silver perchlorate to the 2-pyridyl thioester of 15-hydroxypentadecanoic acid in benzene gave a mixture of the monomeric, dimeric, and trimeric lactones in 44% yield within 30 min. at 20°. 

With the aid of this reagent, a method has been developed for the synthesis of peptides [76]. It proceeds under mild conditions and largely without racemization. The combination of reagents provides a method for the synthesis of macrolides (macrocyclic lactones) from long-chain co-hydroxycarboxylic acids, as demonstrated by the formation of pentadecanolide from 15-hydroxypentadecanoic acid [77]. 

A modern approach to 15-hydroxypentadecanoic acid comprises fermentation of pentadecane with, for example, Candida tropicalis or Cryptococcus neofor-mans, to yield pentadecanedioic acid [172, 190], the mono-alkyl ester of which may be reduced catalyticaUy under high pressure to the corresponding hydroxy-ester. 

Hydroxypentadecanoic acid lactone 15-Hydroxypentadecanoic acid, u-lactone. See Pentadecalactone... 

Hydroxypentadecanoic acid, H-00386 15-Hydroxy-1-pentadeccnc, see P-00053 15-Hydroxy-2-pentadcccnc, see P-00052... 

In 1984, Gatfield [68] observed that a lipase Mucor miehei) is able to catalyze the intramolecular esterification of 15-hydroxypentadecanoic acid to pentadecanolide... 

---