3.4- Dihydroxypentanoic acid

Fig. 7 -31. Peeling and stopping reactions of polysaccharides (Sjostrom, 1977). R = polysaccharide chain and R = CH2OH (cellulose and glucomannans) or H (xylan). Cellulose and glucomannans (R = CH2OH) (1) 3-Deoxyhexonic acid end groups (metasaccharinic acid), (2) 2-C-methylglyceric acid end groups, (3) 3-deoxy-2-C-hydroxymethylpentonic acid (glucoisosaccharinic acid), (4) 2-hydroxypropanoic acid (lactic acid), and (5) 3,4-dideoxypentonic acid (2,5-dihydroxypentanoic acid). Xylan (R = H) (3) 3-Deoxy-2-C-hydroxymethyltetronic acid (xyloisosaccharinic acid), (4) 2-hydroxypropanoic acid (lactic acid), and (5) 2-hydroxybutanoic acid. 1977. TAPPI. Reprinted from Tappi 60(9), p. 152, with permission.

Alkyi-3 -dihydroxypentanoic acids chiral hydroxylactones.1 The acetal (2) of an aldehyde formed from (R)-l couples with l,3-bis(trimethylsilyloxy)-l-methoxy-1,3-butadiene (3), to give a single isomer (4). The chiral auxiliary is... 

Formic acid Propionic acid D-dt-hydroxyisovaleric acid a-n-hexyl-/S,y-dihydroxypentanoic acid... 

Stokker GE, Hoffman WF, Alberts AW, et al. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. 1. Structural modification of 5-substituted 3,5-dihydroxypentanoic acids and their lactone derivatives. J Med Chem 1985 28 347-358. 

The stereochemistry at C4 is probably D although this has yet to be unequivocally established. The structure of (1) was further supported by a FAB mass spectrum which yielded a single intense peak with a m/e ratio of 133, corresponding to the expected molecular weight of the carboxylate anion. A final confirmation of the structure was obtained when the proton-decoupled NMR of (1) (Figure 6) was shown to be identical to authentic DL-4,5-dihydroxypentanoic acid ( ). 

Bromodihydro-4-hydroxy-2(3/7)-furanone, B-111 5-Bromo-3,4-dihydroxypentanoic acid, B-112 3-Bromo-6,8-dioxabicyclo[3.2.1]oct-2-en-4-one, A-508 5-(2-Bromoethenyl)-2 -deoxyuridine, B-52... 

Dihydroxypentanoic acid AR,5R)-form, D-707 3-(Dimethylamino)-2,3,6-trideoxy-/yxo-hexose i.-form, D-727 Ethyl 3,6-anhydro-7-(2-benzoyl-2-deoxy-4,5-0-isopropylidene-D-a//o-... 

Dihydroxypentanoic acid (4Rf>R)-form, D-707 Ethyl l,3,4-tri-0-acetyl-5-deoxy-p-i>/Areo-hex-2-ulopyranoside, D-224 Methyl 2,3-anhydro-5-deoxy-a-i>ribofuranoside, 9CI, A-690 Methyl 2,3-anhydro-5-deoxy-p-D-ribofuranoside, 9CI, A-690 Methyl 5-chloro-5-deoxy-a-D-ribofuranoside, C-100 Methyl 5-deoxy-2,3-0-isopropylidene-fl-D-ri6o-hexofuranoside, D-207 Methyl 5-deoxy-2,3-0-isopropylidene-p-D-ribofuranoside, D-362 Methyl 5-deoxy-D-ribofuranoside, D-362... 

Dihydroxypentanoic acid AR,5R)-form, D-707 3,4 5,6-Di-0-isopropylidene-D-gluconic acid, G-250... 

The fortuitous discovery of mevalonic acid (3-methyl-3,5-dihydroxypentanoic acid) by Folkers and co-workers and by Thmura (110) in 1956 prompted its evaluation as a possible precursor in the biosynthesis of cholesterol. It was found that... 

Formic acid Propionic acid D-a-hydro wisovaleric acid ot-n-hexyl-p,y-dihydroxypentanoic acid 6-diazo-5-oxohexanoic acid 6-methylheptanoic acid (+)-6-methyloctanoic acid 3-hydroxydecanoic acid /3-hydroxytridecanoic acid (+)-12-methyltetradecanoic acid... 

Recently, the US company Arzeda has suggested a novel enzymatic pathway for the fermentive production of y-VL (Fig. 14). The pathway starts with pyruvate, which is derived from the primary metabolism. Pyruvate decarboxylase converts pyruvate into acetaldehyde, which is added by an aldolase to another molecule of pyruvate to 4-hydroxy-2-oxo-pentanoic acid. A specific dehydrogenase reduces this intermediate to 2,4-dihydroxypentanoic acid, and a second catalyzes a selective oxidation of the hydroxyl group on C4 to give 2-hydroxy-4-oxo-pentanoic acid (2-hydroxy-levulinic acid). A hydratase eliminates water and produces 4-oxo-2-... 

Addition to 632 of chiral enolates generated from mandelic acid-derived (S) or (i )-2-hydroxy-l,2,2-triphenylethyl acetate (HYTRA) produces syn or /-dihydroxypentanoates of the type 647 or 648 [195]. In order to achieve the highest diastereoselectivity, the lithium enolates are transmetallated to magnesium in conjunction with carrying out the reaction at —125 to — 135 °C in THF/2-methylbutane cosolvent. 

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