- Reactions of theophyllines. Chemical conversions of 8-aminotheophyllinates
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Thermally stable, colored 8-aminotheophyllinates (betaine derivatives of theophylline) form unstable, colorless salts with strong mineral acids and undergo partial decomposition to a uric acid upon prolonged refluxing with concentrated base solution. Substituted 8-pyridinium theophyllinates readily take part in typical reactions of the functional group in the substituted pyridine ring with retention of the betaine structure. The formation of the synthesized compounds was confirmed by IR and NMR spectroscopy.
- Kuz'menko,Zvolinskaya
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- Particle size control method of 8-chlorotheophylline
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The invention relates to the field of pharmaceutical chemicals, in particular to a particle size control method of 8-chlorotheophylline, and aims at solving the problems that 8-chlorotheophylline produced industrially in the prior art is small in particle size, difficult to centrifuge and time-consuming in process. The method comprises the following steps: (1) raw material selection: selecting theophylline as a raw material and N-chlorosuccinimide as a chlorinating agent, and metering a solvent, an alkali solution and an acid solution; (2) stirring and mixing: adding N-chlorosuccinimide and a solvent into a 20L reaction kettle, and stirring until the mixture is clear; (3) feeding: adding theophylline into the reaction kettle for reaction. The raw materials are low in toxicity, the reaction time is short, side reactions are few, the preparation process is environment-friendly and pollution-free, and the product purity is high; a post-treatment method is adopted to control the particle size of a product, so that a large-particle-size product can be prepared, centrifugal filtration is smooth, working hours are reduced, and energy consumption is reduced; therefore, the particle size of the product is convenient to control, and commercial production is facilitated.
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Paragraph 0040-0086
(2021/05/29)
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- Preparation method of low-cost 8-chlorotheophylline
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The invention discloses a preparation method of low-cost 8-chlorotheophylline. The preparation method of the low-cost 8-chlorotheophylline comprises the following steps: adding theophylline into a mixed solution of DMF and SOCl2, introducing chlorine to react, and crystallizing, washing and drying after the reaction to obtain the final product. According to the method, the target product is synthesized by taking the recyclable DMF as a solvent at one step and the finished product can be obtained by pulping with tap water, so that the cost is low, the pollution is low and the yield is high.
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Paragraph 0019; 0020; 0021; 0022; 0023; 0024; 0025-0038
(2017/08/29)
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- Reactions of some 8-diazoxanthine derivatives
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The coupling reaction of 8-diazo-1,3-dimethyl-(3) and 8-diazo-3-methyl-(4)-xanthines with some active methylene compounds does not give the triazine derivative (5); however, it gives new 8-azoxanthine derivatives (6-16).Nevertheless, compounds 3 and 4 undergo coupling reaction with secondary amines producing novel triazene derivatives (17-21).Heating of 3 with some dipolarophiles in benzene affords the unexpected 8-phenyltheophylline (24), which can be methylated to 8-phenylcaffeine (25). 8-Diazotheophylline (3) has been converted into 8-methoxy- and 8-ethoxy-theophyllines (26) and (27) by reaction with MeOH and EtOH, respectively.The reaction of 3 with 10percent HCl produces 8-chlorotheophylline (28).Structures of the compounds have been estabilished by elemental analyses and spectral data.
- Mosselhi, Mosselhi A N,Abbass, Ikhlass M,Abdalla, Magda A,El-Damaty, Allia A
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p. 236 - 242
(2007/10/02)
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- Purines. XIV [1]. Synthesis and properties of 8-nitroxanthine and its N- methyl derivatives
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Xanthine (1) and its N-methyl derivatives 2-16 have been nitrated to the corresponding 8-nitro derivatives 17-32 under different reaction conditions. Nitration in glacial acetic acid with nitric acid works well with the N-7 unsubstituted and some of the 9-methylxanthines, respectively, whereas the 7- methylxanthine derivatives react best with nitronium tetrafluoroborate in sulfolane or glacial acetic acid. The 8-nitro group can be displaced nucleophilically to form 8-chloro-, 33, 34, 8-ethoxy-, 35, 36, and uric acid derivatives 37-40, respectively. The newly synthesized 8-nitroxanthines have been characterized by elemental analyses, pK-determinations and uv and 1H- nmr spectra.
- Mosselhi,Pfleiderer
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p. 1221 - 1228
(2007/10/02)
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