Convenient synthesis of L-proline benzyl ester.

In the industrial odors, the volatility of Benzyl-acetate is often only an advantage.”

Benzyl formate is found in coffee and coffee products

Peptides containing C-terminal esters are an important class of bioactive molecules that includes a-factor, a farnesylated dodecapeptide, involved in the mating of Saccharomyces cerevisiae. Here, results that expand the scope of solid-phase peptide synthetic methodology that uses trityl side-chain anchoring for the preparation of peptides with C-terminal cysteine alkyl esters are described. In this method, Fmoc-protected C-terminal cysteine esters are anchored to trityl chloride resin and extended by standard solid-phase procedures followed by acidolytic cleavage and HPLC purification. Analysis using a Gly-Phe-Cys-OMe model tripeptide revealed minimal epimerization of the C-terminal cysteine residue under basic conditions used for Fmoc deprotection. 1H NMR analysis of the unfarnesylated a-factor precursor peptide confirmed the absence of epimerization. The side-chain anchoring method was used to produce wild-type a-factor that contains a C-terminal methyl ester along with ethyl-, isopropyl-, and benzyl-ester analogs in good yield. Activity assays using a yeast-mating assay demonstrate that while the ethyl and isopropyl esters manifest near-wild-type activity, the benzyl ester-containing analog is ca. 100-fold less active. This simple method opens the door to the synthesis of a variety of C-terminal ester-modified peptides that should be useful in studies of protein prenylation and other structurally related biological processes.

Benzyl formate occurs in essential oils

T1 - Synthesis and structure-activity studies of benzyl ester meperidine and normeperidine derivatives as selective serotonin transporter ligands

We examined the hydrolysis of dibenzyl ether, benzyl -butyl ether, methyl -butyl ether, methylbenzoate, and diphenylcarbonate in high-temperature liquid water, both with and without added acid or base. The apparent reaction order for H+ did not exceed 0.2 for any of the compounds investigated. This result indicates that hydrolysis of these compounds in high-temperature water (HTW) does not follow the kinetics expected for specific acid catalysis (H+ reaction order = 1.0), as does the hydrolysis at ambient temperatures. Rather, the greater thermal energy in the HTW system allows protonation by water molecules to become faster than protonation by H+ at near-neutral conditions. Because the water-catalyzed path is faster, the occurrence of these acid-catalyzed reactions in HTW with no added acid is not due to the elevated value of w, the ion product. This finding contradicts the conventional wisdom in this field.


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Our efforts to develop novel molecular scaffolds targeting monoamine transporter systems have led to the development of several classes of selective DAT ligands and selective SERT ligands.- Previously, we have reported on a series of derivatives of meperidine (1) that exhibited modest potency and selectivity for the SERT ()., However, unlike the prototypical SSRIs fluoxetine and paroxetine, the meperidine analogues 2 lack a secondary amine and two aromatic moieties common to the SERT pharmacophore., In light of these deficiencies it was of interest to examine this class of meperidine-based SERT ligands to determine if SERT potency could be improved and the monoamine transporter selectivity influenced by the addition of a second strategically placed aryl ring system. To this end, we envisaged a series of benzyl ester normeperidine derivatives 3 that would be similar to the SERT pharmacophore. As illustrated in , the alignment of predicted favorable solvated conformers of benzyl normeperidine 3, fluoxetine and paroxetine suggested that appropriately substituted normeperidine benzyl esters should exhibit high affinity for the SERT. A normeperidine benzyl ester 3 that exhibited potent SERT affinity could then be evaluated at other monoamine transporters or serotonin receptors to determine the potential focus for medication development (e.g. SSRI, TUI, duel SSRI/5-HT1A antagonists). Herein we report the synthesis and monoamine transporter affinity of novel benzyl ester meperidine and normeperidine derivatives.

Synthesis of carnitine benzyl esters as prodrugs | …

Based upon previous structure-activity studies of meperidine analogues, we focused on four 4-aryl (Ar1) piperidine scaffolds (Ar1 = 3,4-dichlorophenyl, 4-Ph-Ph, 4-I-Ph, 2-naphthyl). Previous studies had shown these aryl groups to contribute to the high potency and selectivity at SERT observed for the meperidine ethyl ester derivatives 2a-d () as well as a variety of piperidine and tropane derivatives.- As illustrated in , an initial series of normeperidine derivatives 4 were prepared from the corresponding ethyl esters 2 using 1-chloroethyl chloroformate (ACE-Cl). This two-step one-pot processs typically afforded the normeperidine derivatives 4 in 59% - 73% yield. The benzyl ester derivatives were prepared from the corresponding nitriles 5 () that were readily available using synthetic methods previously reported from our laboratory. Hydrolysis of the nitrile moiety of 5 was achieved in a methanolic solution of sodium hydroxide (25% wt) at reflux, followed by an acidic work-up (2N HCl) to afford the carboxylic acids 6 as the hydrochloride salts in >90% yield. Without purification, the carboxylic acids 6 were converted into the acid chlorides 7 with thionyl chloride and then treated with the appropriately substituted benzyl alcohol under phase-transfer conditions. This furnished the benzyl esters 8-11 in 25-62% yield for the two-step process. The normeperidine analogues 12-15 were then prepared in 70-85% yield using ACE-CI procedure described above.