In the title salt, C(12)H(14)ClN(4) (+)·C(10)H(10)NO(3) (-), zwitterionic N-H⋯O inter-actions form an R(2) (2)(8) ring. The crystal structure is stabilized by N-H⋯O and N-H⋯N hydrogen bonds involving two different eight-membered rings. An N-H⋯O inter-action occurs between the pyrimidine ring (donor) and carboxyl-ate group (acceptor) while the other ring is formed by N-H⋯N inter-actions, which f...

Amiloride (AM), N-amidino-3,5,-diamino-6-chloropyrazinamide hydrochloride, induces natriuretic effects without potassium loss or rise in serum uric acid. 1 , 4 In single doses, AM has been shown to be less potent than hydrochlorothiazide (He); however, when administered daily in approximately maximal dosage, the natriuretic action of AM is sustained for a longer period so that the negative sodi...

In the crystal of the title mol-ecular salt, C(5)H(8)N(3) (+)·C(8)H(5)O(4) (-), the diamino-pyridine cation and the phthalate anion are linked by a pair of N-H⋯O hydrogen bonds. Within the phthalate anion, an almost symmetrical O-H⋯O hydrogen bond is observed. The ion pairs are linked by further N-H⋯O hydrogen bonds, generating a two-dimensional network lying parallel to (10).

Seven pyrimidines with a lipophilic substituent at position 5 have been investigated with respect to inhibition of both dihydrofolate reductases of Sarcoma 180 and Escherichia coli and site of inhibitory action in mammalian cells in culture. Of the 7 pyrimidines, 5 were competitive inhibitors of both dihydrofolate reductases, 1 was noncompetitive, and 1 produced no effect. The Sarcoma 180 enzym...

The kinetics of excision of damaged purine bases from oxidatively damaged DNA by Escherichia coli Fpg protein were investigated. DNA substrates, prepared by treatment with H2O2/Fe(III)-EDTA or by gamma-irradiation under N2O or air, were incubated with Fpg protein, followed by precipitation of DNA. Precipitated DNA and supernatant fractions were analyzed by gas chromatography/isotope-dilution ma...