5616-65-9Relevant academic research and scientific papers
Synthetic equivalents based on Weinreb amide functionality for convenient access to monoprotected α-diketones
Balasubramaniam, Sivaraman,Aidhen, Indrapal Singh
, p. 959 - 963 (2008/02/02)
A convenient new strategy for the synthesis of monoprotected α-diketones has been achieved. The strategy is based on the use of hitherto unreported N-methoxy-N-methyl-1,3-dithiolane-2-carboxamide and N-methoxy-N-methyl-1,3-dithiane-2-carboxamide as synthe
Scope and Mechanism of Deprotection of Carboxylic Esters by Bis(tributyltin) Oxide
Salomon, Claudio J.,Mata, Ernesto G.,Mascaretti, Oreste A.
, p. 7259 - 7266 (2007/10/02)
Methyl and ethyl esters of aliphatic and aromatic carboxylic acids as well as benzyl carboxylates, thiol esters and double esters such as (pivaloyloxy)methyl carboxylates have been successfully cleaved with bis(tributyltin) oxide to give the free carboxylic acids in good yields.The reaction is carried out in aprotic solvents under essentially neutral conditions and thus this method can serve as an ideal procedure for the cleavages of esters with other functional groups and/or protecting groups acid and/or base sensitive.We demonstrated that the reaction displays a high level of chemoselectivity between methyl and ethyl esters versus tert-butyl esters and γ-lactones.Bis(tributyltin) oxide is also a highly efficient reagent for the cleavage of acetates of primary and secondary alcohols and phenols.The limitations we found in the use of this reagent include the lack of cleavage of esters sterically hindered around the carboxyl carbon and the carbinol group (i.e., esters of tertiary alcohols) and in carboxylic esters that contain a fluoroalkyl substituent.A resonable mechanistic explanation is discussed to account for the reaction pathway of the acyloxygen cleavage of (-)-(1R)-menthyl acetate.
4-substituted azetidinones as precursors to 2-substituted-3-carboxy carbapenem antibiotics and a method of producing them
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, (2008/06/13)
New 4-substituted azetidinones having the formulae I and II: STR1 wherein X is oxygen, sulfur or a moiety of the formula NR6 where R1, R2, R3, R4, R5 and R6 are defined hereafter, which are intermediates for the preparation of carbapenem and carbacephem antibacterials and processes for producing such antibacterials through the utilization of an acid mediated ring closure reaction.
4-substituted azetidinones as precursors to 2-substituted-3-carboxy carbapenem antibiotics and a method of producing them
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, (2008/06/13)
New 4-substituted azetidinones having the formulea I and II: STR1 with R1, R2, R3, R4, R5 and X defined hereafter, which are intermediates for the preparation of carbapenem and carbacephem antibacterials and processes for producing such antibacterials through the utilization of an acid mediated ring closure reaction.
Bis (tributyltin) oxide. A mild, neutral and selective reagent for cleavage of esters. Scope and limitation of the reaction
Salomon, Claudio J.,Mata, Ernesto G.,Mascaretti, Oreste A.
, p. 4239 - 4242 (2007/10/02)
Bis(tributyltin)oxide acts as a mild, neutral and chemoselective ester cleavage reagent for a variety of carboxylic esters with good to excellent yields. The acyl-oxygen cleavage mechanism of (-)-(1R) menthyl acetate is discussed.
Synthesis of β-Lactams via Ketene-Imine Cycloaddition Chiral Ketenes Bearing a 1,3-Dithiolane Ring
Abramski, Wojciech,Belzecki, Czeslaw,Chmielewski, Marek
, p. 451 - 457 (2007/10/02)
The reaction of chlorides and ketenes derived from 1,3-dithiolane-2-carboxylic acid and Schiff's bases affords substituted β-lactams.Introduction of chirality into the dithiolane residue leads to diastereoface-differentiation in formation of the four-membered ring.
3-(1,3-Dithian-2-yl)-4-cyclo-pentene-2-carboxylic acids, esters and amides
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, (2008/06/13)
The invention relates to the stereoisomers of novel cyclopentene derivatives and to the preparation thereof. The cyclopentene derivatives are obtained by cycloaddition reaction between cyclopentadiene and a mono-or bis-thioalkyl (or aryl) ketene and r
