6- Hydroxy-4-methylhexanoic acid

Periodate-Permanganate oxidation [1, 810-812, at end]. In carrying out the oxidation of (R)-(+)-citronellol (8) to the 6-hydroxy-4-methylhexanoic acid (9) by the Lemieux-von Rudloff reagent, Overberger and Kaye16 used acetone-water as the medium in order to conduct the oxidation at a higher concentration. 

S,4S,5 E,7E)-3-Amino-4-hydroxy-6-methyl-8-(4-bromophenyl)-octa-5,7-dienoic acid [Aboa = Br-Ahmp, Br-Apoa], (2S,3S,8S,9S)-3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid (Adda). 3-Amino-2,4-dimethylpentanoic acid (Admpa). (2S,3R,5S)-3-amino-2,5,9-trihydroxy-10-phenyldecanoic acid (Ahda). j3-Aminoisobutyric acid (jS-AiB). (3S,4S,5E,7E)-3-Amino-4-hydroxy-6-methyl-8-phenylocta-5,7-dienoic acid [Ahmp (Faulkner) or Apoa (Fusetani)]. (2S,3R,5R)-3-Amino-2,5-dihydroxy-8-phenyloctanoic acid (Ahoa). 3-Aminopentanoic acid (Apa /5-Apa). (2R,3R)-3-Amino-2-methylbutanoic add (Amba). 3-Amino-2-methylhexanoic acid (Amha). 3-Amino-2-methyl-7-octynoic add (Amoa, Amoya). 3-Amino-7-octynoic add (Aoya). (2S,3R)-3-Amino-2-methylpentanoic acid (Map). http // www.ncbi.nlm.nih.gov/ Taxonomy/ tax.html... 

The structure of YA-56 was studied by Ohashi et al.36l. They showed that structural differences between PHM and YA-S6 existed in amine components I and III, and in the gulose moiety. They axe substituted by /3-hydroxy-L-valine, 4-amino-3,6-dihydroxy-2-methylhexanoic acid and 6-deoxy-L-gulose, respectively. The terminal amine was found to be 3-aminopropionamidine, which had not been found in natural PHMs. The total structure of YA-56X can be postulated as shown in Fig. 928.36) YA-56 Y has an additional component, 7-aminobutyric acid. But the position of this amino acid in the molecule is not yet known. 

Methyl-2-hydroxy-5-hexenoic acid with 85%-H3P04 slowly distilled at 30 mm. —2,5-epoxy-2-methylhexanoic acid. Y 75%. (Bl. 1949, 24.) —Cyelization of sec. alcohols is best effected by H3P04, which, however, forms diethylenic hydrocarbons from tert. alcohols (Bl. 1949, 17). (F. e., also via dibromo alcohols, s. J. Colonge and A. Lagier, Bl. 1949, 24, 17.)... 

LeuMstin [(2/(,35)-3-amino-2-hydroxy-2-(IA/-imida-zol-4-ylmethyl)-5-methylhexanoic acid]. 

Alkyl 2-acyloxy-3-deoxy-D-eryt7zr o-hex-2-enopyranoside diesters (91) have been converted into chiral 5-hydroxy-2-methylhexanoic acid lactones which constituted the pheromone of the Carpenter bee. Treatment of (90) with boron trifluoride etherate gave (91), which on addition of methylenetriphenylphosphorane gave a most interesting transformation to (92). A further reaction sequence... 

A different study generated the lithium imine of 2.118 and condensed it with ester 2.119 to give 2.120. Deprotection of the lactam nitrogen with ceric ammonium nitrate and acid hydrolysis led to formation of 3-amino-2-hydroxy-5-methylhexanoic acid, 2.727.57... 

Not only aldehydes are of enormous importance as constituents of flavoring mixtures, but so also are products that can be easily derived from these compounds such as hemiacetals, acetals, or carboxylic acid esters (Scheme 6.1). Noteworthy, lower carboxylic acids (e.g., isovaleric acid [11], 3-hydroxy-3-methylhexanoic acid) [12] emerging from human body or in household have malodourous properties [13]. However, some of them are widely used as... 

Two more compounds that have been identihed as contributors to it are 3-hydroxy-3-methylhexanoic acid ( Spicy ) and 3-methyl-3-sulfanylhexan-l-ol, whose relative amounts seem to be gender-specihc. 

Natsch, A., H. Gfeller, RGygax, J. Schmid and G. Acuna,/. Biol. Chem., 278, 2003, 5718-5727. (Enzyme release of 3-methyl-2-hexenoic acid and 3-hydroxy-3-methylhexanoic acid.)... 

A further significant example is the stereospecific synthesis of (/ , 5 )-5-hydroxy-2-methylhexanoic acid lactone (the major component of the Carpenter bee pheromone) [5 c]. 

The main reaction products upon oxidative decomposition of the ozonide of (-) tetrahydrohumulone are 3-methylbutanoic acid and 4-methylpentanoic acid. Reductive decomposition furnishes in addition 5,5-dimethyltetrahydrofuran-2-one and the optically active 2-hydroxy-5-methylhexanoic acid with unknown optical purity. The reaction sequence for the formation of the hydroxycarboxylic acid is given in Fig. 7. 

The isolated 2-hydroxy-5-methylhexanoic acid belongs to the L-series with S-configuration, as indicated by the positive ORD plain curve (41). It follows that (-) humulone would be the L-form. However, because in the Cahn-Ingold-Prelog nomenclature (37) the sequence of the substituents at the chiral centre in humulone differs from that in the hydroxycarboxylic acid, (-) humulone possesses the R-configuration. This result confirms the conclusion reached from the chiroptical studies. 

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