135052-95-8Relevant academic research and scientific papers
Organometallic Complex Formed by an Unconventional Radical S-Adenosylmethionine Enzyme
Dong, Min,Horitani, Masaki,Dzikovski, Boris,Pandelia, Maria-Eirini,Krebs, Carsten,Freed, Jack H.,Hoffman, Brian M.,Lin, Hening
, p. 9755 - 9758 (2016)
Pyrococcus horikoshii Dph2 (PhDph2) is an unusual radical S-adenosylmethionine (SAM) enzyme involved in the first step of diphthamide biosynthesis. It catalyzes the reaction by cleaving SAM to generate a 3-amino-3-carboxypropyl (ACP) radical. To probe the reaction mechanism, we synthesized a SAM analogue (SAMCA), in which the ACP group of SAM is replaced with a 3-carboxyallyl group. SAMCA is cleaved by PhDph2, yielding a paramagnetic (S = 1/2) species, which is assigned to a complex formed between the reaction product, α-sulfinyl-3-butenoic acid, and the [4Fe-4S] cluster. Electron-nuclear double resonance (ENDOR) measurements with 13C and 2H isotopically labeled SAMCA support a π-complex between the C=C double bond of α-sulfinyl-3-butenoic acid and the unique iron of the [4Fe-4S] cluster. This is the first example of a radical SAM-related [4Fe-4S]+ cluster forming an organometallic complex with an alkene, shedding additional light on the mechanism of PhDph2 and expanding our current notions for the reactivity of [4Fe-4S] clusters in radical SAM enzymes.
Asymmetric synthesis of L-[4-13C]lysine by alkylation of oxazinone derivative as a chiral glycine equivalent
Takatori, Kazuhiko,Hayashi, Akira,Kajiwara, Masahiro
, p. 787 - 795 (2007/10/03)
L-[4-13C]Lysine (2) was synthesized from sodium [2- 13C]acetate (3) and Dellaria's oxazinone 1 as a chiral glycine equivalent. Wittig reaction of the glycinal 7 and 13C-labeled phosphonium ylide 5, prepared from sodium [2-13C]acetate (3), gave the α, β-unsaturated ester 8. The ester 8 was converted to the allylic bromide 10. Alkylation of the oxazinone 1 with 10 proceeded with high diastereoselectivity. Ethanolysis, hydrogenation of the double bond with diimide, removal of the chiral auxiliary, and hydrolysis gave L-[4- 13C]lysine (2). Copyright
Studies of the chemical selectivity of hapten, reactivity, and skin sensitization potency. 1. Synthesis and studies on the reactivity toward model nucleophiles of the 13c-labeled skin sensitizers hex-1-ene- and hexane-1,3-sultones
Meschkat, Emmanuel,Barratt, Martin D.,Lepoittevin, Jean-Pierre
, p. 110 - 117 (2007/10/03)
The potent skin sensitizers hex-1-ene- and hexane-1,3-sultone have been synthesized isotopically labeled with 13C at reactive sites. The reactivity of 2-[13C]- and 3-[13C]hex-1-ene-1,3-sultones and of 3-[13C]hexane-1,3-sultone toward a series of model nucleophiles for protein amino acid residues, i.e., butylamine, diethylamine, imidazole, propanethiol, and phenol, was followed by 13C NMR spectroscopy. The reactivity in water of hex-1-ene-1,3-sultone toward model nucleophiles follows the hard and soft acid and base theory with the hard nucleophiles (primary and secondary amine and phenate) mainly reacting at position 3 by SN substitution, and the soft nucleophiles (thiolate and imidazole) mainly reacting at position 2 by a Michael addition reaction. Hexane-1,3-sultone reacts with model nucleophiles at position 3 by SN substitution. Both saturated and unsaturated sultones are sensitive to hydrolysis when reacted in water.
Chemo-enzymatic synthesis of specifically stable-isotope labelled L-glutamic acid and 2-oxoglutaric acid
Cappon, J. J.,Baart, J.,Walle, G. A. M. van der,Raap, J.,Lugtenburg, J.
, p. 158 - 166 (2007/10/02)
(3-13C)-(4-13C)-,(5-13C)- and (3,4-13C2)-2-oxoglutaric acid were prepared starting from the simple 13C-enriched compounds: ethyl bromoacetate and paraformaldehyde, via a single reaction scheme on the gram scale in high yield.This reaction scheme allows specific 13C enrichment of every carbon position and any combination of positions. (3-13C)-,(4-13C)-, (5-13C), (3,4-13C2) and (15N)-L-glutamic acid were prepared by converting the corresponding 2-oxoglutaric acids via an enantioselective enzymatic conversion.The labelled L-glutamic acids and 2-oxoglutaric acids were characterized by 1H NMR, 13C NMR and mass spectrometry.
Cyclopentadienylideneethenone: Pyrolytic Generation and Argon Matrix Infrared Spectroscopic Study
Brown, Roger F. C.,Browne, Neil R.,Coulston, Karen J.,Eastwood, Frank W.,Irvine, Margaret J.,et al.
, p. 1321 - 1344 (2007/10/02)
Two previously reported pyrolytic precursors for cyclopentadienylideneethenone (4) and benzyne produced two strong infrared bands attributable to ketene type compounds when their pyrolysates were examined by argon matrix isolation spectroscopy.To determine which band should be assigned to (4), four new precursors for (4) and benzyne and two analogues labelled with 13C at the carbonyl group have been synthesized.Precursors (8) and (14) are respectively a caged system and a bridged system bearing a mixed anhydride with trifluoroacetic acid.Flash vacuum pyrolysis of (8) and (14) at 600-700 deg with trapping at 77 K gave pyrolysates which contaned biphenylene.Pyrolysis of (8) and (14) at 600-700 deg in a stream of argon followed by deposition as an argon matrix at about 10 K showed that both produced a pyrolysate absorbing at 2089 cm-1 assigned to (4).Precursors (24) and (25) and the previously reported (18) and (27) are Meldrum's acid derivatives designed to yield the hypothetical cyclopentadienylide Meldrum's acid (19) by cage fission or retro-Diels-Alder reaction.They all gave their biphenylene on flash vacuum pyrolysis at 600-700 deg and their pyrolysates in argon matrices showed absorption both at 2089 cm-1 due to (4) and at 2225 cm-1 due to an unidentified ketene.The frequency shift resulting from substitution of 13C in the carbonyl group (52 cm-1) is in accordance with the assignment of the 2089 cm-1 band to (4).The pyrolysates from precursors (8a), (14), (18a), (25) and (27) were allowed to react with methanol and the resulting mixtures were hydrogenated.In all cases methyl cyclopentylacetate was obtained.
