Notes: Some Reactions Leading to 8-Aminocaffeine

ChemInform Abstract: SYNTHESES AND BIOACTIVITIES OF 1‐(HYDROXYPHENYL)‐1‐NONEN‐3‐ONES AND RELATED ETHERS AND ESTERS

“…were prepared by reacting the appropriate hydroxybenzaldehyde with an alkyloxymethyl chloride followed by condensation with hexyl methyl ketone to give Ib, Id, I f , and IIb, which were hydrolyzed with formic acid to give nuclear hydroxy styryl ketones Ia, Ic, Ie, and IIa. While the methoxy derivatives IIIa and IIIb were prepared by direct condensation of the dimethoxybenzaldehydes with hexyl methyl ketone, this conventional Claisen-Schmidt condition yielded only tars when nitrobenzaldehydes were employed in the attempted preparation of IIIc and IIId; similar problems were encountered in attempting the condensation of y-butyrolactones with nitrobenzaldehydes (19). The failure of these reactions may be due to the high electrophilicity of the carbonyl carbon atom in nitrobenzaldehydes, which may lead to multiple side reactions, including formation of the corresponding phenols (20,21).…”

Theophyllinylpyrimidine Scaffolds Undergo Intramolecular Cyclization Reactions to Form 1,3‐Diazepines and Imidazopurines

“…The clinical pharmacodynamics and biological activities of theophyllines considered in this work have been thoroughly studied in previous work 8. Theophylline derivatives, such as the pharmaceuticals Pamabrom3a and Dimenhydrinate,9 have also demonstrated antitumor10 and anticonvulsant effects 11. Furthermore, theophylline is known to be effective as an active bronchodilator in the treatment of asthma (Figure 2 12…”

Purines. Part XVI

“…Aminoxanthine 14 was also obtained already in 1882 from 8-bromocaffeine in a sealed tube at 1308 with saturated alcoholic ammonia [7]. The 8-amino-7-methylxanthine (15) [17] and 8-aminotheobromine (16) [18] resulted from catalytic reductions of the corresponding 8-(phenylazo) derivatives 17 and 18, and 8-amino-1,7-dimethylxanthine (19) was obtained by three different routes: i) catalytic reduction of 8-azido-1,7dimethylxanthine (20), ii) treatment of 8-bromo-1,7-dimethylxanthine (21) with methanolic ammonia in an autoclav at 1608, and iii) by reaction of 8-(benzylamino)-1,7-dimethylxanthine (22) with concentrated H 2 SO 4 solution at 508 giving the best yield, i.e., 82%. Another approach to 8-aminoxanthines was achieved by base-catalyzed cyclization of 6-amino-1-benzyl-5-[cyanomethylamino]uracil (¼ 6-amino-1-benzyl-5-[cyano(methyl)amino]pyrimidine-2,4-(1H,3H)-dione ¼ N-(6-amino-1-benzyl-1,2,3,4tetrahydro-2,4-dioxopyrimidin-5-yl)-N-methylcyanamide; 23) and its 3-methyl derivative 24 on treatment with 1n NaOH at 808 to give 8-amino-3-benzyl-7-methyl-(25) and 8-amino-3-benzyl-1,7-dimethylxanthine (26).…”