On the Determination of Molecular Potential Curves from Spectroscopic Data

1938 ◽  
Vol 54 (9) ◽  
pp. 726-738 ◽  
Author(s):  
Albert Sprague Coolidge ◽  
Hubert M. James ◽  
E. L. Vernon
2020 ◽  
Vol 15 (3) ◽  
pp. 1934578X2091468
Author(s):  
Shoichiro Inoue ◽  
Jun Takanari ◽  
Keima Abe ◽  
Ayako Nagayama ◽  
Yukinobu Ikeya ◽  
...  

ETAS® has been developed from the stems of Asparagus officinalis L. as a functional ingredient for nutraceuticals. ETAS possesses heat shock protein 70 (HSP70) induction activity and may contribute to maintenance and improvement of health. Here, 3 compounds (1, 2, 3) were isolated from ETAS. The structures of 1, 2, and 3 were deduced by HREIMS and NMR spectroscopic data, and the compounds were identified as cyclo(l-Phe-l-Pro), cyclo(l-Tyr-l-Pro), and cyclo(l-Leu-l-Pro), respectively. Each compound contained a diketopiperazine ring derived from proline with an alkyl group at C-3; thus, we termed them asparagus-derived proline-containing 3-alkyldiketopiperazines (Asparaprolines). In an HSP70 mRNA induction assay in HL-60 cells, Asparaprolines significantly enhanced the expression of HSP70 mRNA compared with a control. To our knowledge, these results demonstrate for the first time that proline-containing diketopiperazines derived from natural amino acids exhibit HSP70 mRNA induction activity.


2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Jixun Zhan ◽  
E. M. Kithsiri Wijeratne ◽  
A. A. Leslie Gunatilaka

Biotransformation of monocillin I (1) by Beauveria bassiana ATCC 7159 was investigated. Two new derivatives 2 and 3 were isolated and identified on the basis of the spectroscopic data. Compounds 2 and 3 are synthesized by hydration at 10,11-double bond and hydrolysis of 14,15-epoxide, respectively. The R configuration of 11-OH in 2 was established by the modified 2-methoxy-2-trifluoromethylphenylacetic acid (MTPA) method. The conversion of 1 to 2 and 3 was reconstituted in an acid solution, indicating that the formation of 2 and 3 is an acid-catalyzed instead of an enzymatic process.


2007 ◽  
Vol 2 (7) ◽  
pp. 1934578X0700200 ◽  
Author(s):  
Mona A. Mohamed

Two new spirostane saponins namely (25 R)-6α-[(β-D-glucopyranosyl)oxy]-5α-spirostan-3β-yl β-D-galactopyranoside (1) and (25 R)-6α-[(β-D-glucopyranosyl)oxy]-27-hydroxy-5α-spirostan-3β-yl β-D-glucopyranoside (2), together with three known metabolites (25 S)-5β-spirostan-3-β-yl O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (3), (25 R)-5α-spirostan-3-β-yl O-β-D-galactopyranosyl-(1→2)- O-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside (4) and (25 R)-5α-spirostan-3-β-yl O-β-D-glucopyranosyl-(1→3)- O-[β-D-xylopyranosyl-(1→2)]- O-β-D-glucopyranosyl-(1→4)-β-D-glactopyranoside (5) were identified from the leaves of Asparagus sprengeri Regel (Asparagaceae). Determination of the structures was based on chemical and spectroscopic data (HRESI-MS/MSn, 1H, DEPT 13C NMR, 1H-1H COSY, HSQC and HMBC). The dry powder, the 1-butanol extract of the leaves, and the isolated compounds (3–5) exhibited molluscicidal properties against Biomphalaria alexandrina snails (the intermediate host of Schistosoma mansoni) [LC90 = 150, 40, 7, 10 and 13 ppm, respectively], while compounds 1 and 2 were molluscicidally inactive.


1982 ◽  
Vol 37 (10) ◽  
pp. 1274-1278 ◽  
Author(s):  
Werner Roll ◽  
Ernst Otto Fischer ◽  
Dietmar Neugebauer ◽  
Ulrich Schubert

The reaction of trans-bromotetracarbonyl(phenylcarbyne)chromium (1) with lithium phenylselenolate and subsequent protonation with aqueous hydrochloric acid leads to (CO)5Cr[Se2(C6H5)2] (3) and (CO)4Cr(μ-SeC6H5)2Cr(CO)4 (4). From 1 and lithium 4-methylphenylthiolate (CO)5CrC(C6H5)SC6H4CH3 (5) and (CO)5CrS(C2H5)(4-CH3C6H4) (6) are obtained, if triethyloxonium tetrafluoroborate is used instead of hydrochloric acid. The analoguous reaction of 1 with lithium phenylselenolate yields the seleno ether complex (7). Reaction conditions, properties, spectroscopic data and the results of an X-ray structure determination of the binuclear complex (4) are reported.


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