Chemical Properties
White Crystalline Powder
Uses
The active component in the diuretic Diurex.
Description
Bromotheophylline is the active moiety of pamabrom, a mixture of 2-amino-2-methyl-propanol and bromotheophylline. From this mixture, bromotheophylline acts as a weak diuretic that has been used along with some analgesics to relieve the symptoms of premenstrual syndrome. Bromotheophylline is categorized on the FDA as a drug substance with an inactive state since March, 1980. It is also approved by Health Canada to be used alone or in combination with [DB00316] in OTC products.
Synthesis
The general procedure for the synthesis of 8-bromo-1,3-dimethyl-1H-purine-2,6(3H,9H)-dione using 1,3-dimethyl-1H-purine-2,6(3H,9H)-dione as a starting material was as follows: the theophylline (10 g, 55.5 mmol) was dissolved in a mixed solvent of acetic acid/water (90 mL of acetic acid, 60 mL of water) at 50 °C, followed by the bromine (9.76 g, 61 mmol) was added slowly and dropwise. The reaction mixture was stirred continuously at 50 °C for 4 hours. Upon completion of the reaction, the mixture was cooled to room temperature to induce precipitation of the target product. The precipitate was separated by filtration and the filter cake was washed twice with distilled water and subsequently dried under vacuum to afford 8-bromo-1,3-dimethyl-1H-purine-2,6(3H,9H)-dione (13.6 g, 94.5% yield) as a white solid. The product was detected by LCMS and showed MH+ peak of 259.
Purification Methods
It is purified by dissolving in the minimum volume of dilute NaOH (charcoal), filtering and acidifying to pH ca 3.5-4. The solid that separates is collected, dried in vacuo at 100o and stored in a dark container. It has also been recrystallised from EtOH or AcOH. [Blitz & Beck J Prakt Chem [2] 118 158 1928, Fischer & Ach Chem Ber 28 3142 1895, Beilstein 26 H 476, 26 II 227, 26 III/IV 2447.]
References
[1] Patent: US2014/275528, 2014, A1. Location in patent: Paragraph 0207; 0208
[2] Chemische Berichte, 1895, vol. 28, p. 3139
[3] Chemische Berichte, 1906, vol. 39, p. 430
[4] Justus Liebigs Annalen der Chemie, 1914, vol. 404, p. 164
[5] Justus Liebigs Annalen der Chemie, 1914, vol. 404, p. 164
