83304-60-3Relevant academic research and scientific papers
Deltamides and Croconamides: Expanding the Range of Dual H-bond Donors for Selective Anion Recognition
Zwicker, Vincent E.,Yuen, Karen K. Y.,Smith, David G.,Ho, Junming,Qin, Lei,Turner, Peter,Jolliffe, Katrina A.
supporting information, p. 1140 - 1150 (2017/12/26)
Dual H-bond donors are widely used as recognition motifs in anion receptors. We report the synthesis of a library of dual H-bond receptors, incorporating the deltic and croconic acid derivatives, termed deltamides and croconamides, respectively, and a comparison of their anion binding affinities (for monovalent species) and Br?nsted acidities to those of the well-established urea and squaramide dual H-bond donor motifs. For dual H-bonding cores with identical substituents, the trend in Br?nsted acidity is croconamides>squaramides>deltamides>ureas, with the croconamides found to be 10–15 pKa units more acidic than the corresponding ureas. In contrast to the trends displayed by ureas, deltamides and squaramides, N,N′-dialkyl croconamides displayed higher binding affinity to chloride than the N,N′-diaryl derivatives, which was attributed to partial deprotonation of the N,N′-diaryl derivatives at neutral pH. A number of differences in anion binding selectivity were observed upon comparison of the dual H-bond cores. Whereas the squaramides display similar affinity for both chloride and acetate ions, the ureas have significantly higher affinity for acetate than chloride ions and the deltamides display higher affinity for dihydrogenphosphate ions than other oxoanions or halides. These inherent differences in binding affinity could be exploited in the design of anion receptors with improved ability to discriminate between monovalent anions.
Efficacious N-protection of O-aryl sulfamates with 2,4-dimethoxybenzyl groups
Reuillon, Tristan,Bertoli, Annalisa,Griffin, Roger J.,Miller, Duncan C.,Golding, Bernard T.
, p. 7610 - 7617 (2012/10/29)
Sulfamates are important functional groups in certain areas of current medicinal chemistry and drug development. Alcohols and phenols are generally converted into the corresponding primary sulfamates (ROSO2NH 2 and ArOSO2NH2, respectively) by reaction with sulfamoyl chloride (H2NSO2Cl). The lability of the O-sulfamate group, especially to basic conditions, usually restricts this method to a later stage of a synthesis. To enable a more flexible approach to the synthesis of phenolic O-sulfamates, a protecting group strategy for sulfamates has been developed. Both sulfamate NH protons were replaced with either 4-methoxybenzyl or 2,4-dimethoxybenzyl. These N-protected sulfamates were stable to oxidising and reducing agents, as well as bases and nucleophiles, thus rendering such masked sulfamates suitable for multi-step synthesis. The protected sulfamates were synthesised by microwave heating of 1,1′-sulfonylbis(2-methyl-1H-imidazole) with a substituted phenol to give an aryl 2-methyl-1H-imidazole-1-sulfonate. This imidazole-sulfonate was N-methylated by reaction with trimethyloxonium tetrafluoroborate, which enabled subsequent displacement of 1,2-dimethylimidazole by a dibenzylamine (e.g. bis-2,4-dimethoxybenzylamine). The resulting N-diprotected, ring-substituted phenol O-sulfamates were further manipulated through reactions at the aryl substituent and finally deprotected with trifluoroacetic acid to afford a phenol O-sulfamate. The use of 2,4-dimethoxybenzyl was particularly attractive because deprotection occurred quantitatively within 2 h at room temperature with 10% trifluoroacetic acid in dichloromethane. The four key steps in the protocol described [reaction of 1,1′-sulfonylbis(2-methyl-1H-imidazole) with a phenol, methylation, displacement with a dibenzylamine and deprotection] all proceeded in very high yields.
SIMPLE AND CONDENSED β-LACTAMS-I. THE APPLICATION OF DIKETENE IN β-LACTAM SYNTHESIS. THE SYNTHESIS AND FUNCTIONAL GROUP MANIPULATIONS OF DIETHYL 3-ACETYL-4-OXOAZETIDINE-2,2-DICARBOXYLATES
Simig, Gyula,Doleschall, Gabor,Hornyak, Gyula,Fetter, Jozsef,Lempert, Karoly,et al.
, p. 479 - 484 (2007/10/02)
Acetylation of the N-substituted diethyl aminomalonates 3a-3d with diketene furnished the ring tautomers 6a-6d of the expected acetoacetyl derivatives 5.By treatment with iodine and sodium ethoxide compounds 6a-6d are smoothly converted into the β-lactam
Azetidinone-4-carboxylate containing a protected 3-acetyl group and process for their preparation
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, (2008/06/13)
The invention relates to new heterocyclic compounds containing a protected C-acetyl group. More particularly, the invention concerns new compounds of the Formula (V) STR1 wherein R is a group suitable for the protection of amides; Z is alkyl; and Y1
Beta-lactam compounds containing a protected C-acetyl group, process for their preparation and pharmaceutical compositions containing them
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, (2008/06/13)
The invention relates to new heterocyclic compounds containing a protected C-acetyl group. More particulary, the invention concerns new compounds of the formula (VI) STR1 wherein R1 is hydrogen or a group suitable for a temporary protection or amides, X is hydroxyl, halogen, cyano or an --O--SO2 --R2 group, in which R2 is lower alkyl or aryl, Y1 and Y2 together form a group suitable for a temporary protection of a keto group. The new compounds possess anaphylactic properties and are valuable intermediates of thienamycin synthesis. Their preparation and the new intermediates obtained during their preparation are also within the scope of the invention.
