title: Formation of Diastereoisomeric Piperazine-2,5-dione from DL-Alanine in the Presence of Olivine and Water.
abstract: DL-Alanine (Ala) was heated with/without powdered olivine and water at 120 °C for 8 days to investigate the formation of the diastereoisomers of piperazine-2,5-dione (diketopiperazine, DKP). When only DL-Ala was heated with a small amount of water, 3.0 % of DL-Ala changed to cis- and trans-DKP after 8 days. DKPs were not detected after heating when no water was added. The presence of a small amount of water is important factor controlling peptide production rates under thermal conditions. When DL-Ala was heated with olivine powder for 8 days, the yields of cis- and trans-DKP were 6.8 and 4.9 %, respectively. The high yield of cis-DKP compared with trans-DKP was attributed to greater thermal stability of cis-DKP. After heating for 8 days, the diastereoisomeric excess of cis-DKP without olivine was 7.3 %, whereas a much higher value of 16.3 % was obtained in the presence of olivine. Taken together, these results show that olivine is not only an efficient catalyst for the formation of DKPs but that it also play a significant role in determining the diastereoisomer selectivity of these cyclic dipeptides.
authors.affiliation: Department of Geoscience, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan. fuchida.shigeshi@nies.go.jp.|Marine Environment Section, Center for Regional Environmental Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan. fuchida.shigeshi@nies.go.jp.
authors.forename: Shigeshi
authors.initials: S
authors.lastname: Fuchida
authors.affiliation: Department of Earth and Planetary Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Naraoka
authors.affiliation: Department of Geoscience, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan.
authors.forename: Harue
authors.initials: H
authors.lastname: Masuda
mesh_terms: D000409:Alanine / Q000737:chemistry*; D002384:Catalysis; D054659:Diketopiperazines / Q000737:chemistry*; D019418:Evolution, Chemical; D058085:Iron Compounds / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry*
chemical_list: D054659:Diketopiperazines; D058085:Iron Compounds; D017616:Magnesium Compounds; D017640:Silicates; D014867:Water; C034475:olivine; D000409:Alanine
keywords: Alanine; Chemical evolution; Diastereoisomeric excess; Diketopiperazine; Olivine