Xanthine derivatives

A xanthine series (I) exemplified by 33 and 34 is another important class of GPR109A agonists [83-88], It is worth noting that members of this series lack the carboxylic acid to interact with Arglll of GPR109A, unlike compounds in the aforementioned series. However, it is conceivable that the N-H present in the bicyclic core of this class of compounds is sufficiently acidic (pKa 5.6) [82] to mimic the function of a carboxylic acid present in the anthranilide class. 

Structurally related to the xanthine series, a triazole ring was employed to tether either one of the two carbonyl groups of the xanthine with the side chain, resulting in two patent applications [89,90]. This 

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Table 2. Xanthine and Xanthine Derivatives Used as Oral Antiasthmatic Agents...

Thiabendazole is contraindicated in patients with known hypersensitivity. Thiabendazole is used with caution in patients with hepatic or renal disease. Thiabendazole is a Pregnancy Category C drug and is used during pregnancy only if the potential benefit outweighs the risk to the fetus. When thiabendazole is administered with the xanthine derivatives, the plasma level of the xanthine may increase to toxic levels. It is important to monitor xanthine plasma levels closely in case a dosage reduction is necessary. 

Examples of the xanthine derivatives (drag that stimulate the central nervous system [CNS] resulting in bronchodilation, also called methylxanthines) are theophylline and aminophylline. Additional information concerning the xanthine derivatives is found in the Summary Drag Table Bronchodilators. 

The xanthine derivatives, although a different class of drag, also have bronchodilating activity by means of their direct relaxation of tlie smooth muscles of the bronchi. 

The xanthine derivatives are used for symptomatic relief or prevention of bronchial asHima and reversible broncliospasm associated with chronic bronchiHs and emphysema... 

If theophylline or anotiier xanthine derivative is given as a rectal suppository, the nurse checks die patient every 15 to 30 minutes to be sure die suppository has been retained. If the patient is unable to retain die suppository, die nurse contacts the primary health care provider because anodier route of administration may be necessary. 

XANTHINE DERIVATIVES. The patient taking theophylline may report heartburn because the drug relaxes the lower esophageal sphincter, allowing gastroesophageal reflux. Heartburn is minimized if the patient remains in an upright position and sleeps with the head of die bed elevated. 

Fig. 1 A) Chromatogram of xanthine derivatives Track 1 theophylline, Track 2 proxiphylline, Track 3 mixture, Track 4 etophylline, IVack 5 caffeine.

Caffeine Xanthine derivatives Purines Purines, pyrimidines Purines Chloraminc-T Iron (111) chloride followed by iodine Silver nitrate followed by sodium dichromate Fluorescein Silver nitrate followed by bromophenol blue... 

Ultraviolet spectroscopy is used in many clinical laboratories due to its ease of operation and availability. A classical method for theophylline determination in plasma is the one of Schack and Waxier.45 The original method had interferences from phenobarbitol and various xanthine derivatives such as theobromine.46 The modification of the method by Jatlow47 eliminated the interferences from barbituates but included the various... 

Varagic, V. M. and Zugic, M., Interactions of xanthine derivatives, catecholamines, and glucose-6-phosphate on the isolated phrenic nerve diaphragm preparation of the rat, Pharmacology, 5, 275, 1971. 

Sulfur atom as internal nucleophile. In this area, it has been shown that the reaction of 8-bromo-l,3-dimethyl-7-(2,3-epithiopropyl)xanthine 147 with a range of aliphatic and aromatic amines generates efficiently 2-amino-substituted 2,3-dihydro-thiazolo[2,3-/]xanthine derivatives 148. The process involves a sequential amine-induced thiirane ring opening followed by thiolate z/MYi-substitution of chlorine atom (Equation 66) <1994PCJ647>. 

J. Leppanen, J. Huuskonen, J. Savolainen, T. Nevalainen, H. Taipale, J. Vepsalainen, J. Gynther, T. Jarvinen, Synthesis of a Water-Soluble Prodrug of Entacapone , Bioorg. Med. Chem. Lett. 2000, 10, 1967-1969 R. Sauer, J. Maurinsh, U. Reith, F. Ftille, K. N. Klotz, C. E. Muller, Water-Soluble Phosphate Prodrugs of l-Propargyl-8-styryl-xanthine Derivatives, A2A-Selective Adenosine Receptor Antagonists , J. Med. Chem. 2000, 43, 440-448. 

Thevis M, Opfermann G, Krug O, Schanzer W. 2004. Electrospray ionization mass spectrometric characteri zation and quantitation of xanthine derivatives using isotopically labeled analogues an application for equine doping control analysis. Rapid Commun Mass Spectrom 18 1553. 

Korman, M., Vindevogel, J., and Sandra, P. (1994). Application of micellar electrokinetic chromatography to the quality-control of pharmaceutical formulations — the analysis of xanthine derivatives. Electrophoresis 15, 1304—1309. 

AminophyUine [Bronchodilator/Xanthine Derivative] Uses Asthma, COPD bronchospasm Action Relaxes smooth muscle (bronchi, pulm... 

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