64826-48-8Relevant academic research and scientific papers
New reactions of the thiocarbonyl function. The synthesis of hindered peptides
Barton, Derek H. R.,Ferreira, J. Albert
, p. 1 - 20 (2007/10/03)
The well-known radical chemistry of the thiocarbonyl function has been expanded to include the concerted reaction between an O-acyl derivative of N-hydroxypyridine-2(1H)-thione (a Barton PTOC ester) and a sulfenamide. The atom-economical process spawned a carboxamide and an unsymmetrical disulfide of synthetic and biological value. The reaction was successfully applied to the synthesis of sterically encumbered, urethane-protected dipeptides. The oxidation-reduction technology pertaining to the disulfide-phosphine combination facilitated the generation of transient Barton PTOC esters. In conjunction with the appropriate benzenesulfenamide, the Barton PTOC ester of benzoyl-L-leucine was shown to preserve optical integrity according to the sensitive Young test, albeit at low temperature. However, the thermodynamic forces at play are powerful and, as a result, the yields were not compromised. In all but the sterically demanding instances, the parent free amine almost matched the reaction time, yield, and enantiomeric excess of the corresponding benzenesulfenamide in its reaction with a Barton PTOC ester.
N-hydroxypyridine-2(1H)-thione derivatives of carboxylic acids as activated esters. Part I. The synthesis of carboxamides
Barton, Derek H. R.,Ferreira, J. Albert
, p. 9347 - 9366 (2007/10/03)
The reaction between an acyl derivative of N-hydroxypyridine-2(1H)- thione (a Barton PTOC ester) and either an amine (primary or secondary), or the corresponding sulfenamide, led to the formation of a carboxamide in a clean transformation requiring minimal work-up and purification. The reaction with a sulfenamide is particularly useful since the only by-product, an unsymmetrical disulfide, is of both synthetic and biological value. In sterically demanding cases, Barton PTOC esters were more reactive towards benzenesulfenamides than to the corresponding free amines.
N-hydroxypyridine-2(1H)-thione derivatives of carboxylic acids as activated esters. Part II. Applications in peptide synthesis
Barton, Derek H. R.,Ferreira, J. Albert
, p. 9367 - 9386 (2007/10/03)
The N-hydroxypyridine-2(1H)-thione derivatives of two urethane-protected α-amino acids readily reacted with the α-amino acid esters or the corresponding benzenesulfenamides to give simple dipeptides in reasonable yields. The benzenesulfenamides are the re
Laser flash photolysis of 2,2′-dithiobis(pyridine N-oxide): Reactivity of N-oxypyridyl-2-thio radical
Alam, Maksudul M.,Watanabe, Akira,Ito, Osamu
, p. 53 - 59 (2007/10/03)
Reaction kinetics of radicals produced by the nanosecond laser flash photolysis of 2,2′-dithiobis(pyridine N-oxide) and related compounds have been studied. The transient absorption band at 360 nm was attributed to the radical in which the unpaired electron mainly localizes on the S atom (N-oxypyridyl-2-thio radical). The reactivities of the radical for conjugated dienes are lower than those of the pyridyl-2-thio radical, suggesting that a considerable unpaired electron density on the S atom delocalizes onto the N-oxypyridine moiety. The addition reaction rate of the radical to the conjugating diene was accelerated with hydrogen-bonding solvents and with addition of the cation, which may stabilize the N+-O- canonical structure, increasing the unpaired electron density on the S atom. By the photolysis of N-hydroxypyridine-2-thione, the N-O bond was predominantly dissociated producing a pyridy1-2-thio radical. By the photolysis of its anion, photoejection took place followed by the N-O bond fission, yielding pyridine-2-thione.
Unsymmetrical disulfides as antimicrobial agents
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, (2008/06/13)
Novel unsymmetrical disulfides of pyridine-1-oxide and acid addition salts thereof, having particular utility as antimicrobial agents per se and in skin cleansing detergent compositions, shampoos, hair dressings, disinfectants, preservatives and the like.
