15-Hydroxypentadecanoic acid lactone

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

Hydroxypentadecanoic acid lactone) (hydroxy fatty acid lactone) ... 

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... 

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%... 

This enzyme system is also capable of producing certain terpene esters in high yield, for example geranyl butyrate. Furthermore, incubation of toluene solutions of hydroxy acids, such as 4-hydroxy-butyric acid and -hydroxypentadecanoic acid, with the enzyme system, gives rise to the corresponding -butyrolactone and the macrocyclic lactone pentadecanolide. 

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]. 

The industrial syntheses of exaltolide start in part likewise from cyclododeca-none. Key reactions are ring expansions and depolymerisation of the polyester of w-hydroxypentadecanoic acid. Of course, ring-closing metathesis also offers an attractive path to macrocyclic lactones. 

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