Some Alkyl Homologs of Theophylline

Abstract

solution were dried over sodium sulfate and evaporated.The semi-solid residue was triturated with 100 ml. of 10% potassium hydroxide, filtered and washed with water. The combined filtrate and washings were extracted twice with chloroform and acidified with 25 ml. of hydrochloric acid. Extraction of the acid solution with five 125-ml. portions of chloroform gave a further 6.3 g. of crude a-mercaptobutyramide; total yield 7.5 g. (42%); m.p. 81-91°. It was not purified further in order to avoid partial oxidation to the disulfide.

Microwave-assisted ring closure reactions: Synthesis of 8-substituted xanthine derivatives and related pyrimido- and diazepinopurinediones

“…A key step in the classical synthetic route towards xanthines is the ring closure of the imidazole ring [15]. An improved ring closure method leading to 8-unsubstituted xanthines by microwave-assisted ring closure reaction of 5,6-diaminouracil derivatives with triethyl orthoformate was recently developed [16].…”

Synthesis of xanthine derivatives by microwave-assisted ring closure reaction

“…As starting materials the 1,3-dialkyl-5,6-diaminouracils 3 and 4 were prepared as previously described. 10 In order to obtain highly pure compounds separation methods for these air-and temperature-sensitive materials had to be developed (see Experimental), since no detailed procedures are given in the literature. Although the subsequent reactions work well with impure starting materials (containing small quantities of water, inorganic salts or other by-products of the synthesis), highly pure 5,6-diaminouracils were required for the precise determination of the yields.…”

“…In 60 mL of 12.5% aq. ammonia solution, 20 mmol of the corresponding 1,3-dialkyl-6-amino-5-nitrosouracil 10 was dissolved. The solution was kept at 50-60 °C, and Na 2 S 2 O 4 (ca.…”

“…The classical Traube synthesis of 8-unsubstituted xanthine derivatives comprises the reaction of a 5,6-diaminouracil derivative with formic acid in a two step procedure, involving tedious workup of the intermediate formamide. 10,11 Scheme 1. Examples of xanthine drugs.…”

Thermal and spectral studies on some tetrachloroaurates of 8-alkyltheophylline derivatives

“…Theophylline derivatives were synthesized according to the method reported by Speer [36]. All the inorganic products used were of analytical reagent grade.…”