The Novel Synthesis of l-Hydroxyproline from d-Glutamic Acid

Abstract

l-Hydroxyproline (1) and d-allo-hydroxyproline (2) were synthesized from d-glutamic acid (3) using the asymmetric center of 3 as that at C4 of 4-hydroxyproline. When the aqueous solution of 1 or 2 was heated at 200 °C for 2 hr, a solution in the equilibrium state, containing 55% of 1 and 45% of 2, was obtained. From this mixture, 1 was obtained by fractional crystallization.

Chemo-Enzymatic Synthesis of Chiral Epoxides Ethyl and Methyl (S)-3-(Oxiran-2-yl)propanoates from Renewable Levoglucosenone: An Access to Enantiopure (S)-Dairy Lactone

“…For example, methyl (S)-3-(oxiran-2-yl)propanoate (1a) has been employed for the synthesis of many compounds such as elicitor [1], Streptrubin B [2] or chiral β-3-substituted homopropargyl [3], thiobutyrolactone [4], γ-hydroxyesters [5], diol-γ or δ-lactones [6], keto-esters [7], (+/´)-4-alkanolides [8] (Figure 1). Classically, epoxides such as 1a are obtained from (S)-γ-hydroxymethyl-γ-butyrolactone (2H-HBO, 2), itself derived from glutamic acid (Scheme 1) [9][10][11][12][13][14][15][16][17][18][19], a natural amino acid that is produced by fermentation on a commercial scale [20]. Glutamic acid is first deaminated to give the intermediate (S)-γ-carboxy-γ-butyrolactone, which was first reported by Austin et al using nitrous acid [11].…”

“…Providing 2 in very good yield and high purity through a lipase-based mediated oxidation, this sustainable synthetic pathway has been studied further by our group as an alternative to the one involving L-glutamic acid to achieve the synthesis of epoxides (S)-1a and (S)-1b (Scheme 2). Classically, epoxides such as 1a are obtained from (S)-γ-hydroxymethyl-γ-butyrolactone (2H-HBO, 2), itself derived from glutamic acid (Scheme 1) [9][10][11][12][13][14][15][16][17][18][19], a natural amino acid that is produced by fermentation on a commercial scale [20]. Glutamic acid is first deaminated to give the intermediate (S)-γ-carboxy-γ-butyrolactone, which was first reported by Austin et al using nitrous acid [11].…”

“…The first one is a 2-step procedure involving the esterification of the carboxylic acid followed by its reduction with NaBH 4 [12,[14][15][16]. The second route is quite similar but uses an acid chloride instead of the carboxylic acid [10]. Finally, the third and last route consists of a one-step reduction of the carboxylic acid into the alcohol in presence of borane-methylsulfide (BH 3 -Me 2 S) [3,17] or borane-THF [18].…”

Synthesis of (+)-Marmelo Lacton A and (+)-Marmelo Lactone B

“…3). (IlIA) was obtained as a syrup quantitatively by treatment of (IIA) with 'SOCI 2 under refluxing 8 ) and converted to (IVA) by the Rosenmund reaction,9"'11) syrup, (80% yield). At the final step the Wittig reaction gave the main 5(E) and 5(Z) isomers of (VA) (EIZ = T e t r a r n e t h y l " , / THF, 20°c thiourea,…”

Synthesis of the sex pheromone of the Japanese beetle

“…The stereospecificity (Brewster et al, 1950;Cervinka and Hub, 1968;Yamada et al, 1969) of the deamination (Austin and Howard, 1961;Plieninger et al, 1961;Ravid et al, 1978) ofR (V) or S glutamic acid has been known for some time, and the lactone acid product VI has been utilized as an intermediate in the synthesis of several natural products (Plieninger et al, 1961;Koga, 1971;Eguchi and Kakuta, 1974;Iwaki et al, 1974;Mori, 1975;Ravid et al, 1978). The stereospecific (Eguchi and Kakuta, 1974) conversion of VI to the acid chloride VII proceeded smoothly in high yield with either thionyl chloride or oxalyl chloride.…”