- Development of new catalytic enantioselective formation of methylenelactam-based N,O-spirocyclic compounds via ring opening-asymmetric reclosure of hydroxylactams
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Catalytic enantioselective formation of methylenelactam-based N,O-spirocyclic compounds is developed. Hydroxylactams prepared from N-carbonyl phthalimides and β-amido functionalized allylboronates underwent ring opening-asymmetric reclosure in the presence of catalytic amounts of MgBr2 and a chiral aminophenol to afford the corresponding N,O-spirocyclic compounds in excellent yields and high enantioselectivities.
- Sengoku, Tetsuya,Miyoshi, Ayako,Tsuda, Tamaki,Inuzuka, Toshiyasu,Sakamoto, Masami,Takahashi, Masaki,Yoda, Hidemi
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- [2,3]-sigmatropic rearrangement of allylic selenimides: Strategy for the synthesis of peptides, peptidomimetics, and N-aryl vinyl glycines
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The scope of the NCS-mediated amination/[2,3]-sigmatropic rearrangement of enantioenriched allylic selenides has been expanded to provide access to three new product classes. The use of N-protected amino acid amides provides a novel strategy for accessing peptide chains containing unnatural vinyl glycine amino acid residues. Also reported is the use of amino acid esters, allowing the diastereoselective synthesis of N,N-dicarboxymethylamines, a motif found in a number of pharmaceuticals. Furthermore, use of a range of N-aromatic and N-heteroaromatic amines allows the formation of enantioenriched N-arylamino acids, a motif found in a number of synthetically and biologically interesting compounds.
- Armstrong, Alan,Emmerson, Daniel P. G.,Milner, Harry J.,Sheppard, Robert J.
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p. 3895 - 3907
(2014/05/20)
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- Regioselective hydration and deprotection of chiral, dissymmetric iminodinitriles in the scope of an asymmetric strecker strategy
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The controlled, selective decomposition of dissymmetric iminodinitriles (DIDN) of formula RCH(CN)-NH-C(CN)R′R″ (considered as N-protected alpha-aminonitriles), is a critical issue for an original asymmetric Strecker strategy previously outlined by us for the enantioselective synthesis of amino acids. This strategy, derived from Harada's work, involves a double sequence of (i) stereoselective Strecker condensation of a chiral ketone R′R″CO with NH3 and HCN, followed by (ii) stereoselective Strecker condensation with an aldehyde RCHO and HCN, then (iii) regioselective retro-Strecker decomposition of the DIDN intermediate to release the target alpha-aminonitrile. In addition to the use of quite simple, cheap cyclic ketones (e.g. carvone derivatives) as chiral auxiliaries, another great advantage of this strategy is that step (iii) enables the recovery of the chiral ketone and hence its reuse. While our previous investigations on step (iii) under various conditions, either preceded or followed by the hydration of the secondary nitrile group RH(CN)- into an amide, had shown insufficient selectivity, we succeeded in the regioselective hydration of the secondary nitrile of DIDN without significant racemisation, by using a large excess of hydrogen peroxide in methanolic/aqueous ammonia (pH 12.5) at low temperature. The resulting imino nitrile/amide compound was then classically decomposed in acidic medium through a retro-Strecker reaction, affording the chiral alpha-amino amide. Alternately, the regioselective retro-Strecker decomposition of the tertiary moiety of the DIDN was achieved by reaction with silver cation in aqueous nitric acid, also without significant racemisation, thus establishing an original, enantioselective synthesis of alpha-aminonitriles. In both reactions, the chiral ketonic auxiliary resulting from DIDN decomposition was recovered in good yields. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Rossi, Jean-Christophe,Marull, Marc,Boiteau, Laurent,Taillades, Jacques
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p. 662 - 668
(2007/10/03)
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- 1-METHYLCARBAPENEM DERIVATIVES
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The present invention relates to 1-methylcarbapenem compounds having excellent antibacterial activity, pharmacologically acceptable ester derivatives thereof, pharmacologically acceptable salts thereof, pharmaceutical compositions (particularly antibacterial agents) containing them as active ingredient, use of the compounds, ester derivatives or salts thereof for preparing such pharmaceutical compositions and a method of preventing or treating diseases (particularly bacterial infections) in which a pharmacologically effective amount of the compound, ester derivative or salt is administered to a warm-blooded animal (particularly a human being). The 1-methylcarbapenem compounds of the present invention are represented by the general formula (I): wherein:R1 is a group represented by the formula COOR3 (wherein R3 represents a hydrogen atom, a C1-C6 alkyl group or the like), a group represented by the formula CONR4R5 (wherein R4 and R5 each independently represent a hydrogen atom, a C1-C6 alkyl group which may be substituted or the like), a cyano group, a group represented by the formula CH2OR6 (wherein R6 represents a hydrogen atom, a C1-C6 alkyl group or the like) or a group represented by the formula CH2NR7R8 (wherein R7 represents a hydrogen atom, a C1-C6 alkyl group or the like, and R8 represents a hydrogen atom, a C1-C6 alkyl group, a C1-C6 alkanoyl group, a C1- C6 alkoxycarbonyl group or the like);R2 represents a hydrogen atom or a C1-C6 alkyl group;n represents 1, 2 or 3; andX represents a sulfur atom or an oxygen atom.
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- Herbicidal imidazolones
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Compounds such as Formula I having herbicidal utility are disclosed: STR1 wherein Q is STR2 R1 is H; alkyl, haloalkyl or halogen R2 is C1 -C2 alkyl optionally substituted with one or more halogens, OR8, CN, COR9, CO2 R31 or CONR32 R33 ; CN; CO2 R34 ; CONR35 R36 ; S(O)n R8 ; S(O)n NR19 R8 or COR37 ; or R1 and R2 can be taken together along with the carbon to which they are attached to form C=CHCO2 R31 ; C=(CH3)CO2 R31 ; C=(C2 H5)CO2 R31 ; C=CHCONR32 R33 ; C=C(CH3)CONR32 R33 or C=C(C2 H5)CONR32 R33.
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- Synthesis of α-amino dithioesters and endothiodipeptides
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The α-amino ester hydrochlorides (1) are converted into N-protected α-amino amides (3), α-amino thioamides (4) and α-amino dithiomethylesters (5). Condensation of 5 with the alkali salts of α-amino acids gives rise to the endothiodipeptide alkali salts (7). Johann Ambrosius Barth 1996.
- Hartke, Klaus,Barrmeyer, Stephan
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p. 251 - 256
(2007/10/03)
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