Dibasic compounds

Dibasic Lead Sulfate. Dibasic lead sulfate [12036-76-9] 2PbOPbSO, is a white powder, mol wt 749.70, mp 961°C. The dibasic compound can be prepared by fusion of the two components. It has been sold as a PVC stabilizer in Japan and is sold in Europe in combination with dibasic lead phosphite. 

For exchange in dibasic compounds, such as aminopyridines, ideally if both equilibrium and kinetic protonations follow H0, a rate profile of the type in Figure 3 should be expected (67JCS(B)1219>. Rate profiles obtained for 4-amino, 4-amino-2,6-dichloro- and 2-amino-5-methyl-pyridine correspond to the portions b-c, c-d and d-e respectively of Figure 3. 

Barker, P. L. Gendler, P. L. Rapoport, H. Acylation of Dibasic Compounds Containing Amino Amidine and Aminoguanidine Functions, J. Org. Chem. 1981, 46, 2455-2465. 

Recall that the fully basic form of a dibasic compound can be treated as if it were monobasic. (The Kb2 reaction can be neglected.)... 

Lakkaraju, A., H. Joshi, S. Varia, and A. T. M. Serajuddin. 1997. pH-solubility relationship of avitriptan, a dibasic compound, as a function of counteriBharm. Res14 S-228. 

Jumping to the end of the spectrum, there is a large, well-defined, sharp peak arriving at the Faraday plate at approximately 11.9 ms. This peak corresponds to the quasi-molecular product ion (MH+) produced from the ionization reaction M -I- H3O+ MH+ + H2O occurring in the liquid phase before the sample is electro-sprayed into the IMS. In addition to the ion peak at 11.9 ms, there is another sharp, well-defined ion peak at a drift time of about 8.9 ms. In IMS, as in mass spectrometry (MS), dibasic compounds with molecular weights greater than about 500 Da can contain two charges after ESI. Thus, the force exerted by the electric field on the... 

Fig. 4. (a) Effects of pH of incubation medium on the relative transport of glycocholate and A -choIylaspartate by everted sacs, (b) Effect of pH of incubation medium on the relative transport of taurocholate and N-choIylamino-ethylphosphonic acid. The dibasic compound is a relatively better substrate for transport at the lower pH, presumably because a greater proportion of the molecules exist as the singly charged species. The / Ka of taurocholate (1.54) is such that the quantity of anion present is not significantly different at the two pH values. From Lack and Weiner (23). 

Calculate the pH of a 0.300 M solution of the dibasic compound piperazine, which we will designate B. Calculate the concentration of each form of piperazine (B, BH+, BHi""). 

Piperazine monohydrochloride is formed when 1 mol of HCl is added to 1 mol of the dibasic compound piperazine ... 

Diamine oxidase has been purified extensively from acetone-dried kidney. The purified enzyme attacks many dibasic compounds, but does not oxidize spermine. More recent studies have employed 62 diamines. Of these, the compounds with one primary amino group and no a-sub-stitution were oxidized. Substitutions on the second nitrogen or the carbon which bears it affect the rate, but do not prevent the reaction. These experiments are interpreted as indicating that the oxidation takes place at the primary amine and is inhibited by adjacent groups, while attachment to the enzyme also occurs through a second group whose structure may be varied. Thus, in histamine the imidazole group serves as a site... 

Along with increases in lipophilicity, it has been shown that the incorporation of a dibasic pharmacophore within the compounds leads to increases in the duration of action of P2-agonists [46]. A medicinal chemistry hypothesis was put in place to design and test a series of dibasic compounds, spanning a range of Upophilicities in order to determine if lipophilic dibasic compounds... 

Figure 20.12 Medicinal chemistry design hypothesis to explore potential dibasic compounds.

Gratifyingly, all the medicinal chemistry-driven design strategies delivered collections of dibasic compounds that maintained both high potency and efficacy at the P2AR, to allow choice in the consideration of compounds as potential clinical... 

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