- Azetidine derivatives, their preparation and pharmaceutical compositions containing them
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Compounds of formula: in which R represents a CR1R2, C═C(R5)SO2R6 or C═C(R7)SO2alk radical, their preparation and the pharmaceutical compositions containing them.
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- Mild and Selective Oxygenation of Sulfides to Sulfoxides and Sulfones by Perfluoro-cis-2,3-dialkyloxaziridines
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Sulfides are oxidized to sulfoxides by stoichiometric amounts of perfluoro-cis-2,3-dialkyloxaziridines 2.The reactions proceed at -40 deg C with nearly complete selectivity and very good yields.Sulfoxides are also oxidized easily by 2 under mild conditions to corresponding sulfones.The oxidation of some bioactive sulfides (promazine, albendazole, biotin, and others) is also reported.
- DesMarteau, Darryl D.,Petrov, Viacheslav A.,Montanari, Vittorio,Pregnolato, Massimo,Resnati, Giuseppe
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p. 2762 - 2765
(2007/10/02)
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- Reagents for rapid peptide synthesis
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This invention relates to compounds of the formula: STR1 wherein R is an electron withdrawing group; R1 is H or COZ; X1 and X2 are independently H, lower alkyl, aryl, aryl lower-alkyl or polystyrene or R and X1 taken together with the carbon atoms to which they are attached form a ring containing from 4 to 15 ring carbon atoms and may contain up to 2 heteroatoms, wherein the heteroatoms are O, S, or N; and Z is an amino acid residue, a peptide residue or a leaving group. The compounds of the present invention are adaptable as blocking or protecting groups for an amine composition useful in peptide synthesis. The present invention is also directed to a method of protecting an amino group of an organic molecule during a reaction which modifies a portion of the molecule other than the protected amino group.
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- The Synthesis of Ketones via α-Silyl Sulphides
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α-Phenylthiosilanes (2) have been prepared by alkylation of the anion (4) derived from the 1-phenylthio-1-trimethylsilylalkane (1).These anions (4) have benn prepared by a variety of methods including, direct deprotonation of (1), displacement of a phenylthio group by lithium naphthalenide addition of an alkyl-lithium to 1-phenylthio-1-trimethylsilylethene (7), and transmetallation of a tributylstannyl moiety.The formation of an alkyl-lithium by reaction of lithium naphthalenide with a phenyl sulphide provided an additional route to (2) from bis(phenylthio)acetals (8).An alternative path to the α-phenylthiosilanes (2) was to reduce the corresponding α-phenylsulphonylsilane (15); these, in turn, being readily available from alkylation or silylation of α-sulphonyl anions.The α-phenylthiosilanes (2) were converted into the O-trimethylsilylphenylthioacetal (18) by the sila-Pummerer rearrangement, although this was complicated by vinyl sulphide (20) formation in certain cases.Subsequent hydrolysis of (18) and (20) gave the ketone (3).
- Ager, David J.
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p. 195 - 204
(2007/10/02)
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- Preparation of Vinylic Sulphones by Peterson Olefination using Phenyl Trimethylsilylmethyl Sulphone
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The anion generated from phenyl trimethylsilylmethyl sulphone using butyl-lithium in dimethoxyethane, readily reacts at -78 deg C with various carbonyl compounds to afford vinylic sulphones on work-up at room temperature.The reaction conditions are tolera
- Craig, Donald,Ley, Steven V.,Simpkins, Nigel S.,Whitham, Gordon H.,Prior, Michael J.
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p. 1949 - 1952
(2007/10/02)
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- Sulfone reagents in organic synthesis. VI. Sulfonyl- and silyl-substituted hydrocarbons as versatile carbanion precursors in organic synthesis
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The basic organometallic chemistry of β-silyl-substituted acetylenic, vinylic and alkyl sulfones has been investigated, with attention being given to metallation, carbometallation and the chemical reduction of carbon-carbon unsaturation. 2-Trimethylsilylvinyl and 2-trimethylsilylalkyl sulfones underwent smooth and stereoselective lithiation with RLi on the carbon α to the sulfonyl group. Carbometallation of vinyl sulfones could be achieved with RMgX or LiCuR2, but acetylenic sulfones carbometallated smoothly only with LiCuR2; with RMgX or RLi, these acetylenes underwent alkyldesulfonylation. The utility in synthesis of these metallo derivatives of sulfonyl-silyl-hydrocarbons is discussed and their value in elaborating carbon skeletons is illustrated for the preparation of alkenes, allenes, carbocycles and stereo-defined vinyl sulfones.
- Eisch, John J.,Behrooz, Mohammad,Dua, Suresh K.
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p. 121 - 136
(2007/10/02)
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