Isoleucine methyl ester

Although not of fatty acid origin another group of scarab beetles utilizes amino acid derivatives as pheromones [119]. The large black chafer, Holotrichia parallela, uses L-isoleucine methyl ester [ 120] and the cranberry white grub, Phyllophaga anxia, uses both L-isoleucine and i.-valine methyl esters [121]. More recently L-isoleucine methyl ester, N-formyl L-isoleucine methyl ester, and N-acetyl L-isoleucine methyl ester were identified in the scarab beetle Phyllophaga elenans [ 122]. These pheromone components are obviously derived from the amino acids isoleucine and valine. 

L-isoleucine methyl ester, N-formyl L-isoleucine methyl ester and N-acetyl L-isoleucine methyl ester. The major component of the male attractant pheromone of the scarab beetle, Holotrichia reynaudi, was identified as anisole. ... 

In contrast to the rutelines, the melolonthine scarabs generally use terpenoid-and amino acid-derived pheromones (reviewed in Leal, 1999). For example, the female large black chafer, Holotrichia parallela Motschulsky, produces methyl (2.S, 3. Sj - 2 - am ino-3-methy lpcn tanoatc (L-isoleucine methyl ester) as an amino acid-derived sex pheromone (Leal et al., 1992 Leal, 1997). There is no direct evidence that the chafer beetles or any other Coleoptera use the shikimic acid pathway for de novo pheromone biosynthesis, but some scarabs and scolytids (see section 6.6.4.2) may convert amino acids such as tyrosine, phenylalanine, or tryptophan to aromatic pheromone components (Leal, 1997,1999). In another melolonthine species, the female grass grab beetle, Costelytra zealandica (White), the phenol sex pheromone is produced by symbiotic bacteria (Henzell and Lowe, 1970 Hoyt et al. 1971). 

Figure 15 (a) Spin echo (b) projection of the SECSY data MAS H NMR spectrum for DMF-d7-swollen Fmoc-isoleucine on Wang resin 1 and (c) solution NMR spectrum for Fmoc-isoleucine methyl ester. 

Asymmetric induction occurs when (S)-l-phenylethylamine hydrochloride is used as the ammonium salt [57], which prompted Waldmann to investigate amino acid methyl esters as chiral auxiliaries the reaction of (S)-isoleucine methyl ester with cyclopentadiene in the presence of 35% aqueous formaldehyde solu-tion/tetrahydrofuran (9 1) afforded the best stereoisomeric ratio (93 7) [62],... 

Waldman et al. [7] extended and improved the asymmetric methodology by utilizing (/ )- and (.S)-amino acid ester hydrochlorides as chiral auxiliaries in analogous aza Diels-Alder processes. A variety of chiral amino acids were evaluated, with isoleucine providing the best asymmetric induction. A typical protocol involves reacting (iS)-isoleucine methyl ester hydrochloride with aqueous formaldehyde in the presence of the diene in water-tetrahydrofuran (11/1) at 0°C. Use of cyclopentadiene provides the corresponding azanor-bomene products, 16 and 17, in excellent stereoisomeric ratio (93/7) in 57% yield (Scheme 2.1). In the case of the less-reactive cyclohexadiene, the corresponding diastereomers are formed at 25 C in a 80/20 ratio in 35% yield. 

The interaction with both synthetic and naturally occurring amino acids has been studied extensively glycine (138, 173, 219-221), a-(173, 219) and /3-alanine (138, 220), sarcosine (219), serine (222), aspartic acid (138, 173, 222-226), asparagine (222), threonine (222), proline (219), hydroxyproline (219), glutamic acid (138, 222-225), glutamine (222), valine (219, 227), norvaline (219), methionine (222, 226), histidine (228, 229), isoleucine (219), leucine (219, 230), norleu-cine (219), lysine (222), arginine (222), histidine methyl ester (228), phenylalanine (138, 222), tyrosine (222), 2-amino-3-(3,4-dihydroxy-phenyl jpropanoic acid (DOPA) (222), tryptophan (222), aminoiso-butyric acid (219), 2-aminobutyric acid (219,231), citrulline (222), and ornithine (222). 

Figure 5. Top Tetraurea calixarene monomers 37 and 38 bearing chiral amino acid ester residues (isoleucine and valine methyl esters, respectively) attached to the urea functions. Norcamphor 39 was the chiral guest used to detect the chirality transfer from the outside to the inner cavity.

Fig. 9 Correlation of (A) the second order rate constants (k2 = kcatIKM) and (B) the transition stabilization (pATS) with the hydrophobicity (it) of the substituent of the amino acid residue for the cleavage of /V-acetylamino acid methyl esters by a-chymotrypsin. The open symbols are for the points for two branched residues (valine and isoleucine). Data from Table A6.8.

The iminium salt 132, generated from benzylamine hydrochloride and aqueous formaldehyde, reacts with cyclopentadiene during 3 h at room temperature to give, after basification, the cycloadduct 133 in nearly quantitative yield (equation 70). Other examples of this reaction are shown in equations 71-75. The separable diastereomers 134 and 135 are formed in the ratio 4 1 from cyclopentadiene, (—)-a-methylbenzylamine hydrochloride and aqueous formaldehyde in a combined yield of 86% (equation 75)62. Hydrochlorides 136 of methyl esters of natural amino acids [(S )-valine, (S )-isoleucine] react with cyclopentadiene and formaldehyde in aqueous THF to produce mixtures of the diastereomers 137 and 138, in which the former predominate (equation 76)63. 

There are also many other types of compounds (11.33) used by insects other than Lepidoptera as sex pheromones. The methyl esters of L-valine and L-isoleucine are used by the cranberry white grub,157 periplanone B by cockroaches, ipsdienol by bark beetles,158 and dean by the olive fruit fly 159 jsocoumarjn is part 0f trail pheromone of the ant, Lasius fuliginosus.160... 

Fig. 4. Chromatogram of separation on a silicone stationary phase of methyl esters of trifluoro-acetylated amino acids of hydrolysate of human fingernail. Sorbent silicone stationary phase. Temperature programme A, 100°C, isothermal B, heating from 100°C at 1.5°C/min C, heating from 116.5°C at 4°C/min D, 140°C, isothermal E, heating from 140°C at 6°C/min to 210°C. Peaks 1 = alanine 2 = valine 3 = glycine 4 = isoleucine 5 = threonine 6 = leucine 7 = norleucine 8 = internal standard 9 = proline 10 = asparagine 11 = glutamine 12 = phenylalanine 13 = tyrosine 14 = lysine. From ref. 13.

The spectral properties of a series of Boc-protected LD-alternating cooligopeptide methyl esters derived from the diastereomeric amino acids l-isoleucine and D-alloisoleucine with D-alloisoleucine as the COOH-terminal residue have been investigated (Lorenzi and Paganetti, 1977). The experimental data suggest that, in cyclohexane, the cooligopeptides (hexamer and octamer) assume helical conformations of the p type, with the same prevailing sense of twist. 

Dosage/response experiments then showed that the biological activity resides mainly with the primary product, namely the (3H,7S)-jasmonic acid to a lesser extent with its methyl ester. Jasmonic acid does not bind as the free acid, but as a conjugate with isoleucine to the same receptor as coronatine, a phytotoxin produced by Pseudomonas syringae. In this conjugate, epimerisation at C-7, which is associated with a dramatic loss in activity, is used by the plants to regulate hormone activity. [82]... 

Elastase (EC 3.4.21.11) an endopeptidase specific for the Elastic (see) in animal elastic fibers. Its inactive precursor, proelastase, is formed in the vertebrate pancreas and converted in the duodenum to elastase by the action of trypsin. The natural substrate of E. is elas-tin, an insoluble protein rich in valine, leucine and isoleucine. E. attacks the peptide bond adjacent to a nonaromatic, hydrophobic amino acid. The best synthetic substrates are therefore acetyl-Ala-Ala-Ala-OCHj and benzoylalanine methyl ester. Benzoylarginine ester (a trypsin substrate), and acetyltyrosine ester (a chymotrypsin substrate) are not attacked by E. 

From a lipid extract of Mycobacterium paratuberculosis a peptido-lipid fraction was isolated thanks to its insolubility in ether. Chemical analysis showed the presence of the amino acids D-phenylalanine, l-phenylalanine, L-leucine, L-isoleucine and the presence of a methyl ester group at the C-terminal end of the peptide moiety. Presence of an N-acyltetrapeptide was suggested (75). However, mass spectrometric invest-... 

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