O-Carboxy-N-oxides

Hydrogen chloride acetic anhydride a-Oxo-N-heterocyclics from o-carboxy-N-oxides... 

G. Pilcher, W. E. Acree Jr., J. R. Powell. Enthalpies of Combustion of the Pyridine N-oxide Derivatives 4-Methyl-, 3-Cyano-, 4-Cyano-, 3-Hydroxy-, 2-Carboxy-, 4-Carboxy-, and 3-Methyl-4-Nitro, and of the Pyridine Derivatives 2-Carboxy- and 4-Carboxy-. The Dissociation Enthalpies of the N-O Bonds. J. Chem. Thermodynamics 1998, 30, 869-878. (b) M. D. M. C. Ribeiro da Silva, personal communication. 

Differential scanning calorimetry was used by Murrill and co-workers (43-45) to elucidate solid - solid phase transitions in a large number of organic compounds. First-order transitions were reported for tetrahedral compounds of the type CR1R2R2R4, where R is methyl, methylol, amino, nitro, and carboxy, as well as for octahedral-type compounds. This technique was also used to detect phase transitions in alkali metal stearates (46), some dibenzazepines, carbazoles, and phenothiazines (16), and the half esters of O-phthalic acid (31). The solid-state decomposition kinetics and activation parameters of N-aryl-N -tosyl-oxydt-imide N-oxides were determined using DSC by Dorko et al. (49). 

A recent report shows that 1,2,3,4-benzotetrazine 1,3-dioxide nitroderivatives 73 (R=N O2) are thiol dependent N O-donors and potent activators of the sGC [73]. Activation of the sGC was inhibited in the presence either of ODQ or of the N O scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethy]imidazoline-l-oxyl-3-oxide (carboxy-PTIO). All products inhibited A DP-induced aggregation of human platelets, with the potency sequence 7-nitro >5,7-dinitro >5-nitro. 

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