Synthesis, Identification, and Biological Study for Some Complexes of Azo Dye Having Theophylline

This article includes the synthesis of heterocyclic azo dye of theophylline by coupling diazonium salt of 4-chloroaniline with theophylline which is, namely, 8-(1-(4-chlorophenyl)azo)theophylline (CPAT). The complexes of cobalt and nickel were prepared by reacting their ions with CPAT ligand in ethanol under 1 : 2 ratio metal-ligand. The CPAT ligand and its complexes were characterized by elemental analysis, infrared spectrometry, electronic absorption spectroscopy, molar conductivity, and magnetic moment. The cobalt and nickel complexes show octahedral geometry having general formula [M(CPAT)2Cl2]. This article addresses the properties of CPAT dye such as photochromic properties. The CPAT dye exhibited obvious and desired changes under irradiation with visible light (405 nm), high sensitive for pH changes which refer to its ability to be analysis indicator. CPAT dye exhibited solvatochromic properties presenting red shift with polar solvent. The CPAT and its complexes show interesting antibiological activities towards Staph. aureus and E. coli bacteria and Aspergillus fungi.

Phosphinic Platinum Complexes with 8-Thiotheophylline Derivatives: Synthesis, Characterization, and Antiproliferative Activity

The platinum mixed-phosphine complexes (SP-4,2)-[PtCl(8-MTT)(PPh3)(PTA)] (2) and cis-[Pt(8-MTT)2(PPh3)(PTA)] (3) (MTTH2 = 8-(methylthio)theophylline, PTA = 1,3,5-triaza-7-phosphaadamantane) have been prepared from the precursor cis-[PtCl2(PPh3)(PTA)] (1), which has been fully characterized by X-ray diffraction determination. Antiproliferative activity tests indicated that the presence of one lipophilic PPh3 and one hydrophilic PTA makes 1-3 more active than the analogues bearing two PPh3 or two PTA. The reactivity of cis-[PtCl2(PPh3)2], cis-[PtCl2(PTA)2], and cis-[PtCl2(PPh3)(PTA)] with the bis(thiopurines) bis(S-8-thiotheophylline)methane (MBTTH2), 1,2-bis(S-8-thiotheophylline)ethane (EBTTH2), and 1,3-bis(S-8-thiotheophylline)propane (PBTTH2) has also been investigated. New binuclear complexes have been prepared and identified by spectroscopic techniques and their antiproliferative activities on T2 and SKOV3 cell lines evaluated.

Topical delivery of N-alkyl-N-alkyloxycarbonylaminomethyl (NANAOCAM) prodrugs of theophylline (ThH)

N(7)-(N-Alkyl-N-alkyloxycarbonyl) aminomethyl (NANAOCAM) prodrugs of theophylline (ThH) have been synthesized and characterized by their solubilities in isopropyl myristate (S(IPM)), solubilities in water (S(AQ)), partition coefficients between IPM and pH 4.0 buffer (K(IPM:4.0)) and by their ability to penetrate hairless mouse skin from IPM (J(MIPM)). The most lipid soluble and water soluble member, N-methyl-N-ethyloxy-carbonylaminomethyltheophylline, gave the highest flux through hairless mouse skin from IPM compared to ThH. The flux of NANAOCAM prodrugs of ThH can be accurately predicted by the Roberts-Sloan (RS) equation.

Novel 1,3-disubstituted 8-(1-benzyl-1H-pyrazol-4-yl) xanthines: high affinity and selective A2B adenosine receptor antagonists

Adenosine has been suggested to induce bronchial hyperresponsiveness in asthmatics, which is believed to be an A(2B) adenosine receptor (AdoR) mediated pathway. We hypothesize that a selective, high-affinity A(2B) AdoR antagonist may provide therapeutic benefit in the treatment of asthma. In an attempt to identify a high-affinity, selective antagonist for the A(2B) AdoR, we synthesized 8-(C-4-pyrazolyl) xanthines. Compound 22, 8-(1H-pyrazol-4-yl)-1,3-dipropyl xanthine, is a N-1 unsubstituted pyrazole derivative that has favorable binding affinity (K(i) = 9 nM) for the A(2B) AdoR, but it is only 2-fold selective versus the A(1) AdoR. Introduction of a benzyl group at the N-1-pyrazole position of 22 resulted in 19, which had moderate selectivity. The initial focus of the SAR study was on the preparation of substituted benzyl derivatives of 19 because the corresponding phenyl, phenethyl, and phenpropyl derivatives showed a decrease in A(2B) AdoR affinity and selectivity relative to 19. The preferred substitution on the phenyl ring of 19 contains an electron-withdrawing group, specifically F or CF(3) at the m-position, as in 33 and 36 respectively, increases the selectivity while retaining the affinity for the A(2B) AdoR. Exploring disubstitutions on the phenyl ring of derivatives 33 and36 led to the 2-chloro-5-trifluoromethylphenyl derivative 50, which retained the A(2B) AdoR affinity but enhanced the selectivity relative to 36. After optimization of the substitution on the 8-pyrazole xanthine, 1,3-disubstitution of the xanthine core was explored with methyl, ethyl, butyl, and isobutyl groups. In comparison to the corresponding dipropyl analogues, the smaller 1,3-dialkyl groups (methyl and ethyl) increased the A(2B) AdoR binding selectivity of the xanthine derivatives while retaining the affinity. However, the larger 1,3-dialkyl groups (isobutyl and butyl) resulted in a decrease in both A(2B) AdoR affinity and selectivity. This final SAR optimization led to the discovery of 1,3-dimethyl derivative 60, 8-(1-(3-(trifluoromethyl) benzyl)-1H-pyrazol-4-yl)-1,3-dimethyl xanthine, a high-affinity (K(i) = 1 nM) A(2B) AdoR antagonist with high selectivity (990-, 690-, and 1,000-) for the human A(1), A(2A,) and A(3) AdoRs.

Synthesis and 5-HT1A/5-HT2A activity of some butyl analogs in the group of phenylpiperazine alkyl pyrimido[2,1-f]theophyllines

New arylpiperazines with a four-methylene spacer containing a terminal pyrimido[2,1-f] theophylline fragment were synthesized, and their 5-HT1A and 5-HT2A receptor affinities were determined. All these compounds displayed a high affinity for 5-HT1A receptors (Ki=0.5-21.5 nM), and low affinity for 5-HT2A ones. The results of in vivo experiments showed that compounds revealed potential agonistic activity at presynaptic 5-HT1A receptors, whereas their functional activity at postsynaptic 5-HT1A sites was diversified. In fact, compounds and behaved like partial agonists, antagonists or agonists of postsynaptic 5-HT1A receptors, respectively. The pharmacological properties of the tested compounds were discussed in comparison with those of the three methylene-analogs described earlier.

Reaction of 7-(2-mesyloxy-2-phenylethyl)theophylline with amines: Synthesis of 1,2,3,6-tetrahydro-6-imino-2-oxo-7H-purine derivatives

Theophylline was converted to 7-(2-phenyl-2-methanesulfonyloxy)ethyl congener and the product was treated with ammonia or primary amines in a mixture solution of water and organic solvents. Two products were proven to be the styrene analogue and 7-(2-amino-2-phenylethyl)theophylline. The structure of the third product was elucidated as the 1,2,3,6-tetrahydro-6-imino-2-oxo-7H-purine derivatives by spectroscopic analysis including HMBC correlation and X-ray crystallography.

Design of a microporous controlled delivery system for theophylline tablets

The aim of present work was to develop a microporous-controlled delivery system for theophylline via coating a blend of PCL and PEG on the surface of tablets, where PCL was the major component of film coating material and PEG was acted as a leachable pore-forming agent when contacting with an aqueous medium. The influences of the type of solvent, the amount of PEG, and the thickness of films on the mechanical and thermal properties of coating films and drug release performance were investigated. The DSC thermograms and FTIR spectra indicated both PCL and PEG remained independently in the blended films. The mechanical data showed a decrease tendency as increase in the amount of PEG in the blends due to highly crystalline character of PEG. Slower evaporation rate of acetone than dichloromethane enhanced phase separation between PCL and PEG during film formation, and resulted in the pore size in films prepared from acetone larger than from dichloromethane. The release rate of coated tablets were increased by increasing the amount of pore-forming agent, and the corresponding values from tablets coated in dichloromethane were less than in acetone. Much denser structure and smaller pore size of films formed from dichloromethane contributed to this result. The release of drug from tablets coated in acetone showed a profile more close to a zero-order constant release profile. The penetration of water into drug core played an important role in influencing drug release pattern.

Synthesis and preliminary pharmacological screening of novel imidazo[2,1-f]theophylline derivatives

The three different kinds of imidazo[2,1-f]theophylline derivatives were synthesized and tested for their CNS activity. A series of alkoxy-alkylamides and amino-alkylamides with basic function, derived from 8-benzyl-6,7-dihydroimidazo[2,1-f]theophylline-7-carboxylic acid showed stimulating influence on CNS as they increased the locomotor activity (compound 8 and 10) or enhanced amphetamine and apomorphine effects in mice (compounds 3, 4 and 9). Compounds 1, 5, 8-10 and 12 had anticonvulsant activity in the pentetrazole test; 12 with anellated imidazol-7-on ring (lactam structure) showed sedative properties and antiserotonin effects.

Platinum complexes of oxopurines: cis-bis(theophyllinato-N7)bis(triphenylphosphine)platinum(II) and cis-chloro(theobrominato-N1)bis(triphenylphosphine)platinum(II) ethanol hemisolvate

The syntheses and structures of two mixed-ligand complexes of platinum(II) with deprotonated oxopurine bases and triphenylphosphine are reported, namely the theophyllinate complex cis-bis(1,2,3,6-tetrahydro-1,3-dimethylpurine-2,6-dionato-kappaN(7))bis(triphenylphosphine-kappaP)platinum(II), [Pt(C(7)H(7)N(4)O(2))(2)(C(18)H(15)P)(2)], (I), and the theobrominate complex cis-chloro(1,2,3,6-tetrahydro-3,7-dimethylpurine-2,6-dionato-kappaN(1))bis(triphenylphosphine-kappaP)platinum(II) ethanol hemisolvate, [PtCl(C(7)H(7)N(4)O(2))(C(18)H(15)P)(2)].0.5C(2)H(5)OH, (II). In (I), the coordination geometry of Pt is square planar, formed by the two coordinating N atoms of the theophyllinate anions in a cis arrangement and two P atoms from the triphenylphosphine groups. In (II), there are two crystallographically independent molecules. They both exhibit a square-planar coordination geometry around Pt involving one Cl atom, the coordinating N atom of the theobrominate anion and two P atoms from the triphenylphosphine groups. The two triphenylphosphine groups are arranged in a cis configuration in both structures. The heterocyclic rings are rotated with respect to the coordination plane of the metal by 82.99(8) and 88.09(8) degree in complex (I), and by 85.91(16) and 88.14(18) degree in complex (II). Both structures are stabilized by intramolecular stacking interactions involving the purine rings and the phenyl rings of adjacent triphenylphosphine moieties.

Structure-activity relationships in a series of 8-substituted xanthines as A1-adenosine receptor antagonists

A series of 8-substituted xanthines were synthesized and their affinity in vitro towards A1, A2A-adenosine receptors was evaluated by radioligand receptor binding assays. All compounds showed a greater affinity and selectivity towards the A1-adenosine receptor than theophylline. The compounds in which the n-proyl group is in 1-position of the xanthine nucleus and the pyridazinone system in 8-position is linked through a chain of two or four carbon atoms, showed the highest affinity and selectivity.

Synthesis, toxicological, pharmacological assessment, and in vitro bronchodilating activity of some 7-theophyllinylacetyloxyglycols

The synthesis of four ester derivatives of 7-theophylline-acetic acid and glycols by DCC/DMAP-mediated esterification under mild conditions was studied. The structures of the synthesized compounds were proved by microanalyses, UV-, IR-, and 1H-NMR data. Acute toxicity assessment of the compounds in mice showed that compounds 2a-d are less toxic than aminophylline. It was shown by in vivo experiments that 2a-d had depressive action on CNS (increasing of hexobarbital sleeping time and decreasing of spontaneous locomotor activity), and they did not influence to a statistically significant extent the normal 24 hour diuresis of rats (except 2c). The results of cardiovascular screening in rats show that compounds 2a and 2c decreased the heart rate of rats. A pharmacological study of the in vitro broncholytic effect (IC50 and pD2 values) of the derivatives and aminophylline showed that 2c exhibited good broncholytic effect in vitro especially in acetylcholine and serotonin induced guinea pig tracheal contraction. It was demonstrated that compounds 2b,c exerted a stronger inhibitory effect on the enzymic activity of phosphodiesterase in concentration 2 x 10(-3) M than aminophylline.

Theophylline derivatives as potential histamine H3-receptor antagonists

Previous results of histamine H3-receptors investigations allowed to formulate a general structure of H3-receptor antagonists. According to this model a series of compounds were obtained. As heterocycles they contained a theophylline moiety connected with a polar group (amine, ester, amide, and thiourea function) via an alkyl chain linked by a spacer to a lipophilic residue. The common distance between xanthine moiety and lipophilic rest was a six-link-chain. Selected compounds did not show significant H3-receptor antagonist activity and were weak antagonists at histamine H1-receptors.

New beta-diketone and 3,5-dimethyl isoxazole derivatives of theophylline as potential bronchodilator agents

Ten new compounds having 7-[(2,4-pentanedione-3-yl)alkyl]- and 7-[(3,5-dimethylisoxazole-4-yl)alkyl]-3,7-dihydro-1,3-dimethyl-1H- purine-2, 6-dione structures were synthesized and their bronchodilator activities investigated using the method based on inhibition of acetylcholine and histamine-induced contractions in guinea pig trachea. None of the compounds were effective on acetylcholine-induced contractions. However, the compounds 4d, 4e, 5d and 5c were potent inhibitors of the bronchospasm induced by histamine, whereas the others (4b, 4c, 5b and 5c) were weak inhibitors.

Bronchodilator activity of theophylline derivatives substituted at the 7-position

Theophylline derivatives with several groups linked at the 7-position were synthesized and their pharmacological activities were studied on guinea pig. Relaxant action in the tracheal muscle was increased in comparison with that of theophylline when the 3(2H)-pyridazinone system was linked to 7-(2-ethyl)-theophylline through the piperazine ring, but decreased when the 7-(2-ethyl)-theophylline was linked to 3(2H)-pyridazinone ring through an amino group.

Synthesis of paraxanthine analogs (1,7-disubstituted xanthines) and other xanthines unsubstituted at the 3-position: structure-activity relationships at adenosine receptors

Synthetic procedures for the preparation of various 3-unsubstituted xanthines, including paraxanthine analogs (1,7-disubstituted xanthines) and 1,8-disubstituted xanthines, were developed. Silylation of 1-substituted xanthines followed by alkylation at the 7-position provides a facile route to paraxanthine analogs. Regioselective alkylation of tris(trimethylsilyl)-6-aminouracil provides 3-substituted 6-aminouracils, which are converted to 1,8-disubstituted xanthines by standard procedures. The ring closure of 3-substituted 5-cyclopentanecarboxamido- and 5-(benzoylamino)-6-aminouracils requires drastic reaction conditions. Affinity for brain A1 and A2 adenosine receptors was determined in binding assays for these and other xanthines with substituents in 1-, 3-, 7-, 8-, and 9-positions. Substitution at the 1-position was necessary for high affinity at adenosine receptors. 1,3-Disubstituted xanthines generally had higher affinity than 1,7-disubstituted xanthines. 1,8-Disubstituted xanthines had high affinity for adenosine receptors; some were highly selective for A1 receptors.

Synthesis and antineoplastic properties of 3'-deoxy-3'-fluoroketonucleoside derivatives. Correlations between structure and biological activity

Three fluoroketonucleosides (6, 8, and 11) have been synthesized by direct oxidation of the fluoro precursors. The presence of the highly electronegative fluorine atom in the alpha position to the carbonyl group favours hydration leading to the gem-diol form so that the beta-elimination process to afford 6 and 8 was made difficult and failed in the case of the difluoro compound 11. The biological activity of compounds 6, 8, and 11 was tested on human peripherical blood lymphocytes stimulated by PHA, and on RAJI and DAUDI cells. The IC50 values showed that, surprisingly, the 3'-enopyranosyl-2'-uloses 6 and 8 have much better antineoplastic activities than their 2'-enopyranosyl-4'-ulose analogues 14 and 15 obtained previously. Moreover, compound 11, which is difluorinated at C-3' and C-6' but does not have a C = C-C = O group in its structure, is also very active. These results emphasize the important biological role played by the fluorine atom in this family of compounds and suggest a peculiar mechanism of action which is until now unspecified.

Isoform-selective mechanism-based inhibition of human cytochrome P450 1A2 by furafylline

Biotransformation reactions catalyzed by human cytochrome P450 1A2 (P450 1A2) appear to play a significant role in both the metabolic clearance of drugs and the activation of environmental contaminants and drugs to toxic or carcinogenic species. Furafylline is a potent and selective inhibitor of P450 1A2 activity in human liver microsomes [Sesardic, D., Boobis, A., Murray, B., Murray, S., Segura, J., De La Torre, R., and Davies, D. (1990) Br. J. Clin. Pharmacol. 29, 651-663] which may be of great utility in defining the role of P450 1A2 in metabolic processes. We have investigated the hypothesis that furafylline is a mechanism-based inhibitor of P450 1A2. Key findings consistent with this hypothesis are the following: (1) Furafylline causes a time- and cofactor-dependent loss of P450 1A2 activity which does not return upon dialysis. (2) The loss of activity is associated with a reduction of P450 spectral content which is in turn proportional in amount to P450 1A2-associated catalytic activity in uninhibited microsomes from 7 individual livers. (3) The inactivation of P450 1A2 is characterized by a Ki of 23 microM, a kinact of 0.87 min-1 and a furafylline depletion-based partition ratio of approximately 3-6 metabolic events per inactivating event. (4) The processing of the C-8 methyl group of furaylline is involved in inactivation as demonstrated by the observation of a deuterium isotope effect of approximately 2.0 on kinact and no effect on Ki when the C-8 methyl group protons of furafylline are replaced with deuterium atoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and pharmacological evaluation of 6-(7-theophylline)-3(2H)-pyridazinone

Since the introduction of theophylline (1) as the first PDE-inhibitor used in the treatment of asthma, there has been intense activity in this area of therapy to design drugs with improved potency and efficacy. Derivatives of theophylline and other purine analogs were prepared and tested as PDE-inhibitors and cardiac stimulants, some of them being several times more active than theophylline. A variety of 4,5-dihydro-6-phenyl-3(2H)-pyridazinone derivatives are PDE-inhibitors like CI-914 (2) which produced a cardiotonic effect accompanied by only slight decreases in blood pressure and moderate increases in heart rate. In a recent report some 6-phenyl-3(2H)-pyridazinones showed a bronchospasmolytic effect more marked than that of xanthines. In this paper we report the synthesis and pharmacological profile of 6-(7-theophylline)-3(2H)-pyridazinone; the synthesis is shown in Scheme 1.

[Synthesis, biotransformation and pharmacodynamics of a new theophylline derivative]

7-[(RS)2-((S)-1-Methyl-2-phenyl-ethylamino)propyl]-theophylline (3) was not described until now. This fenetylline analogue is available by reaction of 7 with an excess of 2 at 150 degrees C. If 2 reacts with 4, an E2-elimination overwhelms SN-nucleophilic displacement yielding compound 5. In vivo studies with male White-Wistar rats, comparing biotransformation of 3 and 1, demonstrate, that the amount of 2 is decreased from 4.7% of (RS)-2 to 1%, probably due to steric hindrance of the attacking monooxygenases by the methyl group at C-11 of 3. Pharmacodynamic studies of 3, tested with mice, gave similar results to those obtained with 1.

Influence of molecular structure on the synergistic action of theophylline or dipyridamole derivatives in the prostaglandin-type inhibition of platelet aggregation

Approximately 30 new derivatives of theophylline and dipyridamole have been prepared and examined as potentiators of the inhibition of platelet aggregation induced by the prostaglandin analogue BW 245C. Potentiating activity has been found to be sensitive to molecular size and also to the presence of specific groups. Polymeric adducts based on dextran, poly(ethylene glycol) or poly(N-vinyl pyrrolidone), and aliphatic esters with alkyl chain-lengths greater than 7 are inactive in potentiation. Derivatives containing carboxyl groups are also inactive. Potentiation is discussed in terms of platelet membrane penetration and extra- and intra-cellular processes. The latter are invoked to account for the enhanced potentiation shown by dipyridamole and derivatives when aggregation is induced by PAF-acether rather than ADP. One derivative of particular interest is the adduct of theophylline with 1,2,5,6-diisopropylidene-D-glucose, containing a furanose ring. This is a more active potentiator than theophylline itself, possibly owing to its molecular resemblance to cAMP. On conversion to the pyranose form all activity is removed.

[The synthesis and anti-inflammatory properties of 7-theophyllineacetic acid derivatives]

Some esters of 7-theophyllinylacetic acid were synthetized, characterized physicochemically and tested for their anti-inflammatory properties. As compared to indomethacin, reference anti-inflammatory drug, all synthetized compounds were less toxic. The anti-inflammatory properties are influenced by the nature of the ester group radicals, the more active having ramified alchils.

(RS), (R)(-) and (S)(+) derivatives of 2-N-arylalkylamino-1-butanol having antiarrhythmic properties

A series of theophyllinyl-7'-ethyl derivatives of (RS), (R)(-) and (S)(+) 2-aminobutanol were synthesized and tested in various models of experimental arrhythmia for their preventive and curative properties; (R)(-) 2-N-theophyllinyl-7'-ethyl amino-1-butanol (1a) and (R)(-) theophyllinyl-7'-ethyl-2-N-methylamino-1-butanol (3a) hydrochlorides showed interesting antiarrhythmic properties. The levorotatory compounds of R configuration showed stronger protective and also therapeutic effect in different experimental arrhythmias.

[7-Substituted theophyllines. V. Azabenzhydrylaminoalkyl derivatives]

Some 7-(azabenzhydrylaminoalkyl)theophyllines were prepared and pharmacologically screened. They showed low toxicity, antidepressant properties and, in some cases, antithrombotic activity.

Analogues of caffeine and theophylline: effect of structural alterations on affinity at adenosine receptors

A variety of analogues of caffeine and theophylline in which the 1-,3-, and 7-methyl substituents have been replaced with n-propyl, allyl, propargyl, and isobutyl and, in a few cases, with chloroethyl, hydroxyethyl, or benzyl were assessed for potency and selectivity as antagonists at A1- and A2-adenosine receptors in brain tissue. Caffeine and theophylline are nonselective for these receptors. Nearly all of the 22 analogues of caffeine are more potent than caffeine itself at adenosine receptors. Replacement of the 1-methyl moiety with n-propyl, allyl, or propargyl substituent has little effect on potency at the A1 receptor while enhancing potency about 7- to 10-fold at the A2 receptor. 3,7-Di-methyl-1-propylxanthine is only slightly (1.4-fold) more potent than caffeine at the A1 receptor while being 10-fold more potent at the A2 receptor. 1,3-Di-n-propyl-7-methylxanthine is also selective for the A2 receptor, being 8-fold more potent than caffeine at the A1 receptor and 40-fold more potent at the A2 receptor. A number of other caffeine analogues including 3,7-dimethyl-1-n-propylxanthine, 7-allyl-1,3-dimethylxanthine, and 1,3-dimethyl-7-propargylxanthine are also somewhat selective for the A2 receptor. The most potent caffeine analogue was 1,3-di-n-propyl-7-propargylxanthine, which was about 100-fold more potent than caffeine at both A1 and A2 receptors. The 10 theophylline analogues were relatively nonselective except for the 1-ethyl analogue and the 1,3-diallyl analogue, which were selective for the A2 receptor, and the 1,3-di-n-propyl, 1,3-diisobutyl, and 1,3-dibenzyl analogues, which were somewhat selective for the A1 receptor. 1,3-Di-n-propylxanthine was 20-fold more potent than theophylline at the A1 receptor and 5-fold more potent at the A2 receptor.

Chemical and pharmacological properties of some 7-beta-hydroxy-gamma-piperazinopropyl-8-benzylaminotheophylli nes

In order to examine the circulatory and bronchospasmolytic activity, new 7-beta-hydroxy-gamma-N4-alkylpiperazinopropyl-8- benzylaminotheophyllines (1, 2, 3) were synthesized and converted to the water soluble dihydrochlorides (1a, 2a, 3a). They showed hypotensive and bronchodilatory effect.

New antihistaminic theophylline or theobromine derivatives

A series of 3,4-dihydro-1,3-dimethyl-7-[3-(4-substituted-piperazin-1-yl)- substituted-alkyl]-1H-purine-2,6-diones and 3,7-dihydro-3,7-dimethyl-1-[3-(4-substituted-piperazin-1-yl)- substituted-alkyl]-1H-purine-2,6-diones was synthesized and evaluated for antihistaminic activity. Some of them displayed good inhibition of both histamine-induced bronchospasm in the anesthetized guinea pig at 10 micrograms/kg by the intravenous route and of passive cutaneous anaphylaxis in the rat at 10 mg/kg by the oral route. Comparison of the two most active compounds revealed a higher antihistaminic activity with the compounds containing a (phenylthio)propyl group (1 and 2) as compared with that containing a phenoxy group. Compound 2 [RS-49014, 3,4-dihydro-1,3-dimethyl-7-[3-[4-[3-(phenylthio)propyl]piperazin-1 -yl]- 2-hydroxypropyl]-1H-purine-2,6-dione] was selected for clinical trials on the basis of a comparative pharmacological study with chlorpheniramine, ketotifen, promethazine, and theophylline.

Theophylline magnesium salicylate, a new xanthine compound

Interaction of 1 mole of magnesium salicylate and 2 moles of theophylline in water precipitated a crystalline compound, identified as theophylline magnesium salicylate pentahydrate from analytical and supportive physicochemical data. Similarly, barium salicylate and theophylline produced theophylline barium salicylate. No precipitates were formed with calcium salicylate or strontium salicylate under the same conditions. Theophylline magnesium salicylate is not a mixture of components and differs in composition from the known theophylline calcium salicylate dihydrate. Unlike the latter compound, it is not alkaline.

Synthesis and properties of 7-hydroxyalkyl- and 7-hydroxyalkylamino-8-benzylaminotheophylline derivatives

In a search for new compounds with cardiovascular activity several derivatives of 8-benzylaminotheophylline with hydroxyalkyl and hydroxyalkylamino substituents at 7-position have been obtained. Some of these compounds were screened for their hypotensive activity.

[Theophylline 7-substitutes. III. Arylderivatives]

Some 7-aryltheophyllines were prepared and pharmacologically screened. They showed low toxicity, sedative properties and, in some cases, anticonvulsant activity.

7-Substituted theophyllines. Part I. Nicotinamide derivatives

Some nicotinamides derived from 7-substituted theophyllines were prepared and pharmacologically screened. They showed a very low coronarodilatory activity, a remarkable antispastic activity and a low toxicity.

Controlled delivery of theophylline: chemistry of 7-acyl- and 7,7'-acylditheophylline derivates

7-Acyl- and 7,7'-acylditheophylline derivatives were prepared from the reaction of theophylline with acid chlorides. In addition, a novel synthesis of these compounds was developed, which proceeds through an acylonium ion generated under mild conditions. The physical properties and stability of the derivative of choice, 7,7'-succinylditheophylline, depend on the synthetic procedure employed. This compound is a useful controlled-release prodrug of theophylline.

Synthesis and pharmacological testing on some theophylline esters

Esters of theophylline-7-acetic acid with different amino alcohols were prepared as possible atropine substitutes, together with esters of some hydroxy acids with beta-hydroxyethyl theophylline. Moreover, esters possessing both theophyllinyl and piperazinyl moieties were prepared with the hope that their spasmolytic activity might be increased. Some of the prepared compounds proved to possess atropine-like activity.

[Theophylline and theobromine derivatives of nitrogen heterocyclic compounds]

7-Theophylline derivatives with 4,6-dihydroxy-5-pyrimidinyl-, 3-oxopiperazinylmethyl- and 4-methyl-3,5-dioxopiperazinylmethyl substituents are described: they can be viewed as structural analogues of a nucleic base pair in the Hoogsteen arrangement; theobromine could be converted into the 1-(3,5-dioxo-4-pyrazolidinyl) derivative, similarly analogous to a base pair in the Watson-Crick arrangement.

Synthesis and properties of 7-hydroxyalkyl-8-benzylaminotheophyllines

The synthetic routes leading to 7-beta-hydroxyethyl- (I) and 7-beta-hydroxypropyl-8-benzylaminotheophylline (II) were described. Particularly the opening of oxazolidine ring in easy available oxazolidine-(2,3-f)-theophyllines with benzylamine was investigated. The structure of I, II and acetyl derivatives Ia, Ib, IIa and IIb was also confirmed by UV spectra.