7020-80-6Relevant academic research and scientific papers
Designing Stability into Thermally Reactive Plumbylenes
Ba?i?, Goran,Zanders, David,Mallick, Bert,Devi, Anjana,Barry, Seán T.
supporting information, p. 8218 - 8226 (2018/07/25)
Lead analogues of N-heterocyclic carbenes (NHPbs) are the least understood members of this increasingly important class of compounds. Here we report the design, preparation, isolation, structure, volatility, and decomposition pathways of a novel aliphatic NHPb: rac-N 2,N 3-di-tert-butylbutane-2,3-diamido lead(II) (1Pb). The large steric bulk of the tert-butylamido moieties and rac-butane backbone successfully hinder redox decomposition pathways observed for diamidoethylene and -ethane backbone analogues, pushing the onset of thermal decomposition from below 0 °C to above 150 °C. With an exceptionally high vapor pressure of 1 Torr at 94 ± 2 °C and excellent thermal stability among Pb(II) complexes, 1Pb is a promising precursor for the chemical vapor deposition (CVD) and atomic layer deposition (ALD) of functional lead-containing materials.
SILYLATED AZULENYL NITRONE SPIN TRAPS AS CHROMOTROPIC SUPEROXIDE DETECTORS
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Page/Page column 38, (2013/05/22)
Silylated nitrones and methods of detecting and/or superoxide using silylated nitrones are disclosed herein.
PROCESS FOR PRODUCING QUINOLINE COMPOUND
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Page/Page column 6, (2008/06/13)
By a production method of a quinoline compound represented by the formula (I), which comprises reacting quinolinecarbaldehyde represented by the formula (II) with an imine compound represented by the formula (III) and then subjecting the resulting compoun
Total synthesis of amiclenomycin, an inhibitor of biotin biosynthesis.
Mann, Stephane,Carillon, Sophie,Breyne, Olivier,Marquet, Andree
, p. 439 - 450 (2007/10/03)
We describe the first synthesis of amiclenomycin, a natural product that has been found to inhibit biotin biosynthesis and, as a consequence, to exhibit antibiotic properties. Structure 1, with a trans relationship between the ring substituents. had previously been proposed for amiclenomycin on the basis of its 1H NMR spectrum. We have prepared the trans and cis isomers 1 and 2 by unequivocal routes and we conclude that the natural product is in fact the cis isomer 2. The properly substituted cyclohexadienyl rings were constructed first. A cycloaddition reaction between 1,2-di(phenylsulfonyl)ethylene and the N-allyloxycarbonyl diene 13, followed by reductive elimination of the phenylsulfinyl groups, gave the cis isomer 15. To obtain the trans isomer, the O-trimethylsilyl diene was used to give the cis hydroxylated Diels-Alder adduct 33, which was transformed into the corresponding trans amino derivative by means of a Mitsunobu reaction. The L-alpha-amino acid functionality was introduced by means of a Strecker reaction on the aldehydes 16 and 42, followed by enzymatic hydrolysis with immobilised pronase.
Synthesis of Stenusine, the Spreading Agent of the Beetle Stenus comma
Stevens, Christian,Kimpe, Norbert de
, p. 132 - 134 (2007/10/02)
Stenusine, , the spreading agent of Stenus comma, was synthesized by a six-step sequence in 21 percent overall yield from acetaldehyde.Acetaldehyde was converted into the corresponding N-tert-butyl aldimine, which was sequentially alkylated via its 1-azaallylic anion with 1-bromo-2-methylbutane and 1-bromo-3-chloropropane.The resulting δ-chloro-aldimine was hydrolyzed into the δ-chloro aldehyde, which was converted into the corresponding N-ethyl-aldimine.The latter labile δ-chloro aldimine was cyclized with lithium aluminum hydride to afford stenusine.The 1-tert-butyl analogue of stenusine was synthesized using an analogous route.
Synthesis of vinylisocyanate
Konig
, p. 7729 - 7734 (2007/10/02)
N-1-chloroethylcarbamoyl chloride 3 is generated by selective photohalogenation of ethylisocyanate 2 (or carbamoyl chloride). On dehydrohalogenation with suitable aliphatic isocyanates or with N,N-dimethylacetamide vinylisocyanate 6 is obtained in good yields.
Mechanism of reduction of trityl halides by lithium dialkylamide bases
Newcomb, Martin,Varick, Thomas R.,Goh, Swee-Hock
, p. 5186 - 5193 (2007/10/02)
Trityl chloride (TCl) and bromide are reduced by hindered lithium dialkylamide bases in THF to give predominantly triphenylmethane and a small amount of trityl dimer. Rate constants for the reduction of TCl by lithium diisopropylamide and lithium tert-butylethylamide in THF at -78 ?C have been measured; the reactions are first order in monomeric base and in trityl chloride. Inter- and intramolecular kinetic isotope effect studies employing β-deuterium substituted bases and substituent effect studies coupled with other kinetic information were used to formulate a scheme for the reactions. The reactions proceed by a rapid predissociation of the trityl halide to form an ion pair containing the trityl-THF oxonium cation followed by diffusion controlled electron transfer (ET) from the monomeric form of the base to the trityl-THF oxonium ion. The radical pair thus formed reacts by fast, highly regioselective β-hydrogen atom transfer from the aminyl radical to the methine carbon of the trityl radical to give triphenylmethane. Radical escape from the cage is a minor competing process. An outer-sphere ET process is energetically acceptable, but an inner-sphere process appears to be more likely.
Evidence for Cyclic Azaphosphiridine Oxide Intermediates in the Methoxide-induced Rearrangements of N-Alkyl α-Chlorophosphonamidates: Formation of Phosphoramidates as well as α-Aminophosphonates
Harger, Martin J. P.,Williams, Andrew
, p. 563 - 569 (2007/10/02)
The N-butyl α-chlorophosphonamidates RCHClP(O)(NBut)OMe (R=H, Me, or Ph) react with benzyltrimethylammonium methoxide in tetrahydrofuran-methanol to give two types of rearrangement product, the α-aminophosphonates ButNHCHRP(O)(OMe)2 and the phosphoramidates But(RCH2)NP(O)(OMe)2.For the phosphoramidates it seems necessary to postulate the formation of a cyclic azaphosphiridine oxide intermediate, and its subsequent ring-opening, by nucleophilic attack of methoxide at phosphorus, with cleavage of the P-C bond.The α-aminophosphonates are probably also derived from the azaphosphiridine oxide, by cleavage of the P-N bond.The observation that the proportion of the phosphoramidate (P-C cleavage) increases as R changes from Me to H to Ph accords with this picture, as does the apparent lack of any P-C bond cleavage in the rearrangement of Me2CClP(O)(NHR')OMe (R'=Me or But).
