10448-49-4Relevant articles and documents
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Berger
, p. 559,563,567 (1970)
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One-pot Synthesis of Acid Anhydrides from Acids Using N,N,N',N'-Tetramethylchloroformamidinium Chloride under Mild Conditions
Fujisawa, Tamotsu,Tajima, Kazuhisa,Sato, Toshio
, p. 3529 - 3530 (1983)
N,N,N',N'-Tetramethylchloroformamidinium chloride reacted smoothly with a variety of carboxylic and phosphoric acids in the presence of a tertiary amine to give the corresponding acid anhydrides in high yields.
Activation of the Carboxy Terminus of a Peptide for Carboxy-Terminal Sequencing
Boyd, Victoria L.,Bozzini, MeriLisa,Guga, Piotr J.,DeFranco, Robert J.,Yuan, Pau-Miau,et al.
, p. 2581 - 2587 (1995)
Previously, we reported a new method of sequencing proteins from the carboxy terminus (C-terminus).The carboxyl group at the C-terminus is activated and derivatized into a thiohydantoin (TH).We reported that, by alkylating the TH formed at the C-terminus, the TH is converted into a readily displaced leaving group.Reaction with (-) under acidic conditions cleaves the alkylated thiohydantoin (ATH) and derivatizes the freshly exposed C-terminus into a new proteinyl-TH.The efficiency of the initial activation of the carboxy group at the C-terminus is critical to the initial yield of the first ATH residue.In order to directly observe the intermediates that form during activation of the C-terminus, a model tripeptide, acetyl-alanine-alanine-alanine-OH (Ac-Ala-Ala-Ala-OH) was subjected to the reagents used to form the peptidyl-TH, Ac-Ala-Ala-Ala-TH.The reaction was monitored by nuclear magnetic resonance spectroscopy.An oxazolone was observed to form immediately at the C-terminus during the reaction with diphenyl chlorophosphate (DPCP), tetraphenyl pyrophosphate (TPPP),or tetramethylchlorouronium chloride (TMU-Cl).The oxazolone was observed to react with an excess of the carboxy group-activating reagents while under basic conditions.Diketopiperazine formation at the C-terminus was also observed.These side reactions prevent or retard the reaction of (-) to form a peptidyl-TH and correlate with a reduced initial yield observed during automated C-terminal protein sequencing.The carboxylic acid-reactive reagents react with the side-chain carboxylic acid groups of aspartic and glutamic acid residues as well as the C-terminus.We found that the side-chain carboxylic acid gropus in a protein could be selectively amidated in the presence of the proteinyl-oxazolone at the C-terminus.
Reactive intermediates in the H-phosphonate synthesis of oligonucleotides
Powles, Nicholas,Atherton, John,Page, Michael I.
scheme or table, p. 5940 - 5947 (2012/08/28)
The formation of H-phosphonate diesters is an important step in the synthesis of oligonucleotides. Using diphenylchlorophosphate as the activator for the coupling step is often accompanied by side reactions as a result of self 'capping' and other reactions of the reactive intermediate. In the absence of base, the activation of ethyl H-phosphonate with diphenylchlorophosphate probably occurs through the intermediate formation of bis diethyl pyro-di-H-phosphonate rather than the expected diphenyl ethyl pyro-H-phosphonate. Pyridine acts as a nucleophilic catalyst converting diphenylchlorophosphate to its pyridinium adduct. Several side and unwanted reactions are quantified so that conditions to minimise these can be identified.
New aspects connected with the synthesis of H-phosphinate anhydrides
Nycz
experimental part, p. 589 - 594 (2009/12/26)
A novel reaction between sodium salt of phenylphosphinic acid PhP(O)(OH)H (1) and various phosphorus electrophiles, R2P(O)C1 (2; R = alkyl, aryl, alkoxy or aryloxy) has been described. The presented reaction showed a high selectivity (yield up to 96%) in the products of the symmetric phosphorus anhydrides, R2P(O)-O-(O)PR2(4), which preferentially come from the starting phosphorus electrophiles (2). The results demonstrate that the phosphorus-phosphorus mixed anhydrides, RPH(O)-O-(O)PR2(3) are unstable under basic condition and possibly decomposed with expulsion of a phosphinylidene (Ph-P=O) fragment (6).
