9- Methyldecanoic acid

MeHep = 6-methylheptanoic acid [929-10-2], MeOct = 6-methyloctanoic acid [504-99-4], C2H g02, MeDec = 8-methyldecanoic acid... 

S)-3-,-5-,-7-Methyldecanoic acid Figure 6.19 Resolution of 2- to 8-methyldecanoic acids. 

R - (Z)-4-decanoic acid R - 8-mcthylnonanoic acid R = n-decanoic acid R - 8-methyldecanoic acid R - 9-methyldecanoic acid... 

A strain of B. circulans produces a broad spectrum antibiotic designated as EM 49. This antibiotic is a mixture of closely related lipopeptides which contain five DAB residues out of eight amino acids like the octapeptins. The structure of the peptide moiety of EM 49 is identical with that of octapeptin (Table 8). The fatty acids of EM 49 are 3-hydroxy fatty acids with 10 or 11 carbon atoms. They were identified as 3-hydroxy-8-methylnonanoic acid, 3-hydroxydecanoic acid and 3-hydroxy-8-methyldecanoic acid (752). 

Fig. 16. Binding pocket of the lipase from P. aeruginosa for the acid part of 2-methyldecanoic acid p-nitrophenyl ester showing the geometric position of amino acids 160-163 which were randomized in cassette mutagenesis (49).

Methyldecanoic acids with remotely located methyl branches have been subjected to esterifications under similar conditions with 1-hexadecanol in cyclohexane at aw = 0.8. Here, R-seleclivi ly is the result for the 3-, 5-, and 7-methyldecanoic acids (E = 21, 58, and 17, respectively), whereas one obtains S-selectivity for the 2-,... 

C11H20O4 pentamethylene glycol dipropionate 10025-09-9 519.45 45.756 2 22851 C11H2202 6-methyldecanoic acid 53696-14-3 489.73 35.478 2... 

A second example of the use of directed molecular evolution for natural product synthesis is the use of lipases by Reetz and colleagues. This work is based on the kinetic hydrolytic resolution of racemic mixtures, in which one enantiomer is preferentially hydrolyzed and the chiral product is thus enriched. Utilizing both random mutagenesis and directed techniques such as CAST,64 they have improved the stereoselectivity of a lipase from Pseudomonas aeruginosa (PAL) on a number of occasions with different substrates. One of the first examples utilized the model substrate 2-methyldecanoic acid /xnitrophenyl ester, for which the wild-type enzyme has an enantioselectivity of E= 1.1. As a consequence of five mutations accumulated through random mutagenesis, followed by saturation mutagenesis, the enantioselectivity was increased to 25.8.123 More... 

In a classical study the lipase-catalysed enantioselective hydrolysis of racemic p-nitrophenyl-2-methyldecanoate was chosen as the test reaction [15] (Fig. 8). The p-nitrophenyl ester was employed in the kinetic resolution instead of the methyl or ethyl ester, in order to make screening possible [76] (see below). The lipase from the bacterium Pseudomonas aeruginosa PAOl [77] was used as the enzyme [ 15]. The wild-type enzyme shows an enantioselectivity (ee) of only 2 % in favour of the (S)-configured 2-methyldecanoic acid, which means that the enzyme had essentially no preference for either of the enantiomeric forms. 

The lipase from Pseudomonas aeruginosa (PAL) catalyzes the hydrolysis of 2-me-thyldecanoic acid p-nitrophenyl ester with only 2% ee in favor of the (S)-acid. Reetz and Jaeger used four rounds of error-prone PCR and screening on enantiomerically pure R and S substrates to generate a more enantioselective variant that produced the desired (S)-acid with 81% eell57l Additional cycles of error-prone PCR in combination with saturation mutagenesis further improved the enantioselectivity of this enzyme, which hydrolyzes the 2-methyldecanoic acid p-nitrophenyl ester with 91 % ee (E = 25.8) in favor of the (S)-acid 1Z. ... 

Vinylamycin, a 14-membered cyclodepsi-peptide ( depsipeptides) isolated from the culture broth of Streptomyces sp. (MI982-63F1). Vinylamycin consists of D-valine, alanine, 4-amino-2,4-pentadienoic acid, and 2-hydroxy-3-(2-hydroxyethyl)-4-methyldecanoic acid. It exhibits broad and moderate antimicrobial activities against Gram-positive bacteria [M. Igarashi et al., J. Antibiot. 1999, 52, 873]. 

The lUPAC name for a carboxylic acid is based on the name of the hydrocarbon with the same number of carbon atoms. The ending -oic is appended, as in ethanoic acid, which is the lUPAC name for acetic acid. Draw the structure of the following acids (a) methanoic acid, (b) pentanoic acid, (c) 2-chloro-3-methyldecanoic acid. 

---