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Background: Human milk banks have been established to provide human milk to preterm infants who are unable to obtain milk from their mothers. Donor screening methods vary, and prospective donors are commonly screened for drug and recreational substance use through behavioral screening. Although the risk of illegal drug consumption in Japan is extremely low, caffeine may be consumed unknowingly and can be found in human milk. To date, only a few reports have been conducted on the concentration of caffeine in donor milk., Research Aim: This study aimed to examine the pre-pasteurization levels of caffeine in human milk donated to a milk bank in Japan., Methods: This was a cross-sectional, observational study of caffeine concentrations in human milk donated to a human milk bank in Japan. Caffeine concentration in the donor milk was measured using high-performance liquid chromatography., Results: Caffeine was detected in 70% of the donor milk samples ( N  = 350). The median (range) of caffeine concentration was 0.46 [< 0.10, 7.54] mg/L, and 64.0% of the samples had less than 1 mg/L of caffeine. The caffeine concentration varied widely among as well as within individuals., Conclusion: The average caffeine concentration in Japanese donor milk samples was higher than that previously reported in samples from Spain, but the range was similar. Donors should be informed that caffeine intake should be within a moderate range, to further increase the safety of donor milk., Competing Interests: Disclosures and Conflicts of InterestThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: KM received consulting fees from the Japan Human Milk Bank Association. NM and NN are employed by the Japanese Human Milk Bank Association.

Objectives: We evaluated retrospectively the daily target coverage using cone-beam computed tomography (CBCT) in breath-hold image-guided radiotherapy (BH-IGRT) for gastric lymphoma., Methods: BH-IGRT was performed using a prescribed dose of 30.6 Gy in 17 fractions for the whole stomach. We assessed the target coverage of the whole stomach on daily CBCT images [daily clinical target volume (CTV)], which was delineated individually by two observers. We evaluated V 95% (percentage of volume receiving ≥95% of the prescribed dose) of daily CTV., Results: In total, 102 fractions from 6 patients were assessed. The mean V 95% of daily CTV was 97.2%, which was over 95%. In two of six patients, the V 95% of daily CTV was over 95% for either observer in all fractions. One patient had significant interobserver variation ( p = 0.013). In 95 fractions (93%), the V 95% of daily CTV was over 95% for either observer., Conclusion: Daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable, even when using CBCT., Advances in Knowledge: A previous study ascertained good daily target coverage in BH-IGRT for gastric lymphoma using in-room CT. Even when using CBCT in our study, daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable., (© 2021 The Authors. Published by the British Institute of Radiology.)

The purpose of the present retrospective study was to evaluate the feasibility of hippocampal dose-volume parameters associated with memory decline for intensity-modulated radiotherapy (IMRT). In total, 18 patients who underwent IMRT for supratentorial tumors were analyzed. Prescribed doses of IMRT in 30 fractions were 60 Gy to planning target volume (PTV) 1 of the local area and 48-51 Gy to PTV2 of the extended local area. Based on previous literature, the present study investigated dose-volume parameters of the bilateral hippocampi: D 40% of 13.1 Gy, D 50% of 29.6 Gy, and V 55Gy of 5.0%. It was evaluated which of the parameters was most achievable, and unfavorable factors that interfere with reaching these parameters were identified. As a result, D 40% of 13.1 Gy, D 50% of 29.6 Gy and V 55Gy of 5.0% were achieved in 17, 67 and 33% of patients, respectively. For D 50% of 29.6 Gy, PTV2 ≥500 cc (P=0.004) and tumor in temporal/corpus callosum/basal ganglia (P=0.009) were significant unfavorable factors. In conclusion, D 50% of 29.6 Gy was most achievable. In daily clinical practice, it should be primarily attempted to achieve D 50% of 29.6 Gy of the bilateral hippocampi., (Copyright © 2020, Spandidos Publications.)

Aim: The aim of this study was to compare the ocular and systemic absorption of brimonidine (BMD) and brinzolamide (BZM) in rabbits after the topical administration of a fixed-combination ophthalmic suspension of 0.1% BMD tartrate and 1% BZM (FCBB) with that after the administration of the respective single-drug formulations., Materials and Methods: Ocular and systemic drug absorption was estimated by determining BMD and BZM concentrations in the aqueous humor, retina/choroid, vitreous body, and blood/plasma by liquid chromatography/tandem mass spectrometry after the administration of FCBB, 0.1% BMD tartrate ophthalmic solution (0.1% BMD), or 1% BZM ophthalmic suspension (1% BZM) to rabbits., Results: In concomitant administration, instilling 0.1% BMD and 1% BZM successively without interval lowered aqueous humor concentrations of both drugs compared to those observed with a 5-min interval. After FCBB administration, BMD and BZM concentrations in the aqueous humor were comparable with those observed after the administration of 0.1% BMD and 1% BZM, whereas BMD concentrations in posterior ocular tissues were equal to or higher than those observed after 0.1% BMD. Plasma BMD concentrations following the administration of FCBB were 0.8-fold lower than those after 0.1% BMD; no remarkable differences were observed in blood BZM concentrations for both formulations., Conclusions: FCBB achieved drug distribution in the aqueous humor and systemic exposure that were comparable to those for the single-drug formulations. The viscosity of FCBB may increase BMD distribution in the retina/choroid. The administration interval affects ocular drug absorption with the concomitant administration of 0.1% BMD and 1% BZM, which can be overcome by using the fixed-combination of both drugs.

Background: We aimed to demonstrate the contribution of anti-inflammatory and anti-virulence effects of azithromycin (AZM) in ocular surface infection treatment., Methods: Staphylococcus aureus was injected into the corneal stroma of rabbits to induce keratitis. AZM at concentrations of 0.01, 0.1, and 1% was instilled into the eye twice daily. The eyes were examined using a slit lamp and scored. The viable bacteria in the cornea were counted at 48 h post infection. To evaluate the anti-inflammatory efficacy of AZM, S. aureus culture supernatant-induced anterior ocular inflammation in rabbit was examined using a slit lamp and scored. To evaluate the inhibitory effect of AZM on bacterial toxin production, S. aureus was cultured with AZM and hemolytic reaction in the culture supernatant was determined., Results: In the bacterial keratitis model, AZM dose-dependently inhibited the increase in the clinical score. The viable bacterial count in the cornea treated with 1% AZM significantly decreased compared with that of the vehicle, whereas bacterial count in 0.01 and 0.1% AZM-treated corneas was similar to that of the vehicle. In the anterior ocular inflammation model, 0.1 and 1% AZM inhibited the increase in the clinical score. AZM inhibited hemolytic reaction at concentrations that did not inhibit bacterial growth., Conclusions: The results demonstrated that AZM has not only anti-bacterial, but also anti-inflammatory effects, and inhibits bacterial toxin production leading to ocular surface damage in bacterial infection. Thus, the therapeutic effect of AZM against ocular infections is expected to be higher than that which could be assumed if it only had anti-bacterial activity.

Introduction: This study was aimed to compare ocular tissue distribution and systemic exposure of brimonidine and timolol after single topical administration to rabbits of fixed-combination ophthalmic solution of 0.1% brimonidine tartrate and 0.5% timolol and single drugs (0.1% brimonidine tartrate ophthalmic solution or 0.5% timolol ophthalmic solution) or concomitant administration of single drugs., Methods: Rabbits were treated with a single topical administration of each ophthalmic solution or concomitant administration of single drugs. For concomitant administration, 0.1% brimonidine tartrate was administered after 0.5% timolol instillation successively within 10 s (without interval) or with 5-min intervals. Brimonidine and timolol concentrations in the aqueous humor, retina/choroid, vitreous body, and plasma were determined with liquid chromatography-tandem mass spectrometry., Results: The area under the curve values of both drugs in the aqueous humor after fixed-combination administration were comparable to those after concomitant administration. The value of brimonidine was comparable to that after 0.1% brimonidine tartrate administration, whereas the value of timolol was 1.6-fold higher than that after 0.5% timolol administration. The plasma area under the curve value of brimonidine did not differ between fixed-combination and single-drug administrations, but that of timolol was higher after fixed-combination administration than after single-drug administration. Similar concentration-time curves of brimonidine were observed in the posterior ocular tissues in all groups. For concomitant administration, both drug concentrations in the aqueous humor without an administration interval were lower than those with 5-min intervals., Conclusion: There was no difference in the effect of formulation compositions on ocular and systemic pharmacokinetics among the ophthalmic solutions, but brimonidine may alter the ocular and systemic absorption of timolol, which is possibly due to its pharmacologic action. We demonstrated the importance of an administration interval in the concomitant administration of these drugs. This concern could be avoided by using a fixed combination of brimonidine and timolol.

Introduction: Brimonidine bioavailability in the aqueous humor depends on the solution pH following topical administration. The purpose of this study was to investigate the effect of solution pH on brimonidine distribution in the posterior ocular tissues in pigmented rabbits., Methods: The anterior retina/choroid, posterior retina/choroid, and vitreous body of pigmented rabbits were collected 0.67, 1.5, 3, 6, 12, 24, 168, and 360 h after the administration of a single topical dose of 0.2% brimonidine tartrate ophthalmic solution, pH 6.4 (Alphagan ® ; Allergan Inc., Irvine, CA, USA). Brimonidine concentrations in these tissues were quantified using liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters were determined using noncompartmental analysis, and the results were compared with tissues from eyes administered 0.1% brimonidine tartrate ophthalmic solution, pH 7.3 (Aiphagan ® ; Senju Pharmaceutical Co., Ltd., Osaka, Japan) in our previous study conducted using the same procedure., Results: Topically applied brimonidine was distributed rapidly into the posterior tissues of the eye after a single ophthalmic administration of the 0.2% ophthalmic solution. The areas under the curve from time 0 to 360 h following dosing with the 0.2% ophthalmic solution were 500,000, 14,300, and 28.7 ng h/g in the anterior and posterior retina/choroid, and vitreous body, respectively., Conclusion: The differences in the areas under the curve between two ophthalmic solutions were less than the difference in drug concentrations between these two products in any tissues. This finding indicates that the change in the solution pH from 6.4 to 7.3 increases brimonidine bioavailability into the posterior ocular tissues similarly as into the aqueous humor., Funding: Senju Pharmaceutical Co., Ltd.

Purposes: To establish the in silico ocular pharmacokinetic modeling for eye drops, and to simulate the dose regimen for FK962 in human choroid/retinal diseases., Methods: Pharmacokinetics for FK962 in vivo was performed by a single instillation of drops containing 0.1% 14 C-FK962 in rabbit eyes. Permeation of FK962 across the cornea, sclera, and choroid/retina was measured in vitro. Neurite elongation by FK962 was measured in cultured rat retinal ganglion cells. Parameters from the experimental data were used in an improved in silico model of ocular pharmacokinetics of FK962 in man., Results: The mean concentration of FK962 in ocular tissues predicted by in silico modeling was consistent with in vivo results, validating the in silico model. FK962 rapidly penetrated into the anterior and posterior segments of the eye and then diffused into the vitreous body. The in silico pharmacokinetic modeling also predicted that a dose regimen of 0.0054% FK962 twice per day would produce biologically effective concentrations of FK962 in the choroid/retina, where FK962 facilitates rat neurite elongation., Conclusions: Our in silico model for ocular pharmacokinetics is useful (1) for predicting drug concentrations in specific ocular tissues after topical instillation, and (2) for suggesting the optimal dose regimens for eye drops. The pharmacodynamics for FK962 produced by this model may be useful for clinical trials against retinal neuropathy.

Purpose: Several studies showed that repeated topical administration of brimonidine tartrate ophthalmic solution reached the human vitreous concentration above 2 nM, which is the concentration necessary to activate the α 2 -adrenergic receptor. The purpose of this study was to elucidate the relationship of the brimonidine concentration in the vitreous body to the free concentration in the retina/choroid which is the target site of brimonidine on neuroprotective effect after topical administration., Materials and Methods: Brimonidine concentrations in the eye tissues of pigmented rabbits were determined following single ocular administration of 0.1% brimonidine tartrate ophthalmic solution at pH 7.3. Binding affinity of brimonidine to melanin and melanin content in the retina/choroid of pigmented rabbits was also examined. The concentration of free brimonidine which did not bind to melanin in the retina/choroid was calculated using the binding parameters to melanin., Results: Topically applied brimonidine rapidly distributed to intraocular tissues. The elimination rate from melanin-containing tissues such as the iris/ciliary body and retina/choroid was slower than the aqueous humor and vitreous body in pigmented rabbits. In both the anterior and posterior retina/choroid, the free brimonidine concentrations were over 100-fold lower than the total concentrations. The concentrations in the vitreous body closely matched to the free concentrations in the posterior retina/choroid. Simulated free concentrations in the posterior retina/choroid were gradually increased when 0.1% solution was instilled twice daily., Conclusion: The present data indicated that the brimonidine concentration in the vitreous body was comparable to the free concentration in the posterior retina/choroid. This suggests that the vitreous concentration can be a surrogate indicator of the free brimonidine concentration in the posterior retina/choroid. From the present findings, it is expected that multiple instillation of brimonidine tartrate ophthalmic solution may produce the sufficient free concentration for activation of the α 2 -adrenergic receptor in the retina/choroid in human.

Purpose: To determine the vitreous and aqueous concentrations of brimonidine after topical application of the ophthalmic solution 0.1%., Methods: The prospective observational case series included patients with an idiopathic epiretinal membrane or macular hole who were scheduled for a pars plana vitrectomy. Brimonidine tartrate ophthalmic solution 0.1% was topically administered twice daily for 1 week preoperatively. Vitreous and aqueous humor was collected before vitrectomy, and then, the brimonidine concentration was measured with liquid chromatography tandem spectrometry (LC/MS/MS)., Results: Twenty-four patients (19 phakic eyes and 5 pseudophakic eyes) were enrolled. The mean concentrations in the aqueous humor and vitreous were 336.0 ± 276.2 and 4.8 ± 3.2 nM, respectively. A significant relationship was observed between the vitreous and aqueous samples (P = 0.034, R(2) = 0.22). Nineteen (79%) of the 24 eyes showed more than 2 nM of brimonidine tartrate concentration in the vitreous. In the phakic eyes, the mean concentration of brimonidine in the vitreous was 4.9 ± 3.3 nM, while the mean concentration in the pseudophakic eyes was 4.1 ± 2.4 nM, demonstrating no significant difference between pseudophakic and phakic eyes (P = 0.59)., Conclusions: After 1 week of dosing, in most of the patients who topically received brimonidine tartrate 0.1%, the concentration in the vitreous of the molecule was above 2 nM, which is known to activate neuroprotective α-2 receptors in animal retina. The drug penetration into the vitreous seems to be independent of lens status.

Purpose: To evaluate the pharmacokinetics and efficacy of topically applied nonsteroidal anti-inflammatory drugs (NSAIDs) in the retinochoroidal tissues of rabbits., Methods: The cyclooxygenase (COX) inhibitory activity of diclofenac, bromfenac, and amfenac, an active metabolite of nepafenac, were determined using human-derived COX-1 and COX-2. Each of the three NSAIDs was applied topically to rabbits, and after 0.5 to 8 hrs, the concentration of each drug in the aqueous humor and the retinochoroidal tissues was measured by liquid chromatography-tandem mass spectrometry. The pharmacokinetics of the drugs in the tissues after repeated doses as is done on patients was calculated by a simulation software. The inhibitory effect of each NSAID on the breakdown of the blood-retinal barrier was assessed by the vitreous protein concentration on concanavalin A-induced retinochoroidal inflammation in rabbits., Results: The half-maximal inhibitory concentration (IC50) of diclofenac, bromfenac, and amfenac was 55.5, 5.56, and 15.3 nM for human COX-1, and 30.7, 7.45, and 20.4 nM for human COX-2, respectively. The three NSAIDs were detected in the aqueous humor and the retinochoroidal tissue at all-time points. Simulated pharmacokinetics showed that the levels of the three NSAIDs were continuously higher than the IC50 of COX-2, as an index of efficacy, in the aqueous humor, whereas only the bromfenac concentration was continuously higher than the IC50 at its trough level in the retinochoroidal tissues. The intravitreous concentration of proteins was significantly reduced in rabbits that received topical bromfenac (P = 0.026) but not the other two NSAIDs., Conclusions: Topical bromfenac can penetrate into the retinochoroidal tissues in high enough concentrations to inhibit COX-2 and exerts its inhibitory effect on the blood-retinal barrier breakdown in an experimental retinochoroidal inflammation in rabbits. Topical bromfenac may have a better therapeutic benefit than diclofenac and nepafenac for retinochoroidal inflammatory diseases.

Improved dosing regimens have been proposed for various antimicrobial agents by application of pharmacokinetic/pharmacodynamic (PK/PD) principles. However, for topical ophthalmic use there are several limitations to changing the dosing regimen, such as drug formulation and bioavailability. In this study, we investigated the relationship between dosing interval and antibacterial efficacy in an in vitro PK model mimicking post-operative endophthalmitis. The in vitro PK model simulated the aqueous humour concentration following topical application of 0.3% gatifloxacin ophthalmic solution to rabbit eyes. A clinical isolate of Enterococcus faecalis was exposed to gatifloxacin three times repeatedly at various intervals from 0 h to 8 h. The area between the control growth curve and the bacterial killing and re-growth curve for 24 h (ABBC) was used to evaluate efficacy. The ABBC showed bell-shaped dependence on the dosing interval with a peak at 3h. Under limited condition of total exposure amount, i.e. area under the concentration-time curve, the antimicrobial efficacy appears to be associated with the cumulative time of a 24-h period such that the concentration exceeds the minimum inhibitory concentration (T>MIC) rather than the peak concentration:MIC ratio. The length of intermission of T>MIC during repeated dosing appears to be proportional to the decrease in efficacy of gatifloxacin against E. faecalis. A longer dosing interval, as long as T>MIC is continuous, would likely be more efficient at preventing post-operative enterococcal endophthalmitis. However, further investigation is necessary to explore whether this model is applicable to a variety of pathogens and drugs.

Purpose: To determine how a secreted protease contributes to the pathogenesis of post-cataract endophthalmitis caused by Enterococcus faecalis using an aphakic rabbit endophthalmitis model., Setting: Department of Ophthalmology, Ehime University School of Medicine, Ehime, Japan., Methods: The pathogenesis of E faecalis OG1S (secreted protease-positive) and E faecalis OG1X (secreted protease-negative derivative of OG1S) was compared. After lens removal by phacoemulsification, either strain was inoculated into the lens bag. Changes in bacterial growth, electroretinography (ERG), and pathology of eyes were comparatively monitored throughout the course of the infection. Alternatively, culture fluid from either strain was injected into the vitreous body and ERG and pathology of the eyes were also examined., Results: The levels of growth in the anterior chamber and vitreous cavity were similar for both strains. However, infection with OG1S resulted in a significantly greater reduction in ERG b-wave amplitude than OG1X. Histological examination showed that the posterior lens capsules were severely affected in eyes infected with OG1S, and inflammatory cells and cocci were found in the anterior vitreous cavity 24 hours after the infection. By 48 hours, the retina architecture was profoundly affected in eyes infected with OG1S. In contrast, few pathological changes were noted in the posterior lens capsules and retina of eyes infected with OG1X. Culture fluid in which OG1S had grown decreased ERG b-wave amplitude and caused morphological changes of the posterior capsule and retina similar to those in the infected eye., Conclusion: An extracellular protease plays a major role in the pathogenesis of E faecalis-induced postoperative endophthalmitis.

Purpose: The aim of this study was to determine the efficacy of 0.3% gatifloxacin ophthalmic solution in preventing bacterial endophthalmitis in rabbits., Methods: Eighty-four (84) albino phakic rabbits were injected unilaterally with 2 x 10(4) colony forming units of Enterococcus faecalis into the anterior chamber. The eyes received 0.3% ofloxacin ophthalmic ointment or 0.3% gatifloxacin ophthalmic solution with different regimens in three separate experiments: (1) 1 or 3 drops of gatifloxacin every 2 h or a single application of ofloxacin for 1 day; (2) 3 drops/day of gatifloxacin application started at 0, 6, and 24 h postinoculation, or 1 drop at 0 h, and 3 times daily gatifloxacin for the following 3 days; and (3) 1 or 3 drops of gatifloxacin application started at 0 h and no further application for the following 3 days. The control eyes received no treatment in the three experiments. The effectiveness of these different regimens was assessed by slit-lamp biomicroscopy and bacterial colony counts. The ocular penetration of the drugs was determined in a separate experiment, using 36 normal albino rabbits., Results: The concentration-time curves for gatifloxacin and ofloxacin appeared parallel, with mean peak concentrations of 1161 and 219 ng/mL, respectively, at 1 h postinstillation. In Experiment 1, gatifloxacin significantly reduced the inflammation and the number of living bacteria in the aqueous humor, compared with controls, whereas ofloxacin ointment did not. A single application of ofloxacin ointment was not better than 1 drop of gatifloxacin. The results of Experiment 2 showed that the effectiveness of gatifloxacin decreased as the interval between the inoculation and the onset of treatment increased. In Experiment 3, only 3 drops of gatifloxacin on day 1 kept the inflammation significantly lower than that in the control for 4 days., Conclusions: Immediate postoperative prophylaxis would likely be effective in reducing the risk of enterococcal endophthalmitis by topical gatifloxacin.

Antiviral activity of 1,3-disubstituted uracil derivatives was evaluated against HIV-1 and HCMV. It appears that the nitrogen of the 1-cyanomethyl group is important for anti-HIV-1 activity, suggesting interaction with the amino acid residues of HIV-1 reverse transcriptase. 1-Arylmethyl derivatives also exhibited good anti-HIV-1 activity; and that of the 2- and 4-picolyl derivatives was particularly excellent.

3-(3,5-Dimethylbenzyl)uracil (3) was treated with alkyl halides in the presence of alkali to give 1-substituted congeners. Condensation of 3 with alcohols using the Mitsunobu reaction was also employed as an alternative method. The anti-HIV-1 activity of 1-substituted analogues of 3-(3,5-dimethylbenzyl)uracil was evaluated according to previously established procedures. It appeared that the nitrogen of the 1-cyanomethyl group is important for anti-HIV-1 activity, suggesting interaction with the amino acid residue of HIV-1 reverse transcriptase. 1-Arylmethyl derivatives also showed good anti-HIV-1 activity; and that of 2- and 4-picolyl derivatives was particularly excellent. These results were confirmed by Docking Studies using the program, Glide ligand docking jobs, which suggests hydrogen bonding between amide N-H of Lys 101 and nitrogen of the cyanomethyl and picolyl group.

1,3-disubstituted uracils were obtained from uracil by the stepwise alkylation at N-1 and N-3 position with alkyl halide/alkali or alcohol under Mitsunobu conditions. The antiviral activity against HIV-1 of these compounds was examined to find that 1-cyanomethyl-3-(3,5-dimethylbenzyl)uracil and 1-phenyl-3-(3,5-dimethyl-benzyl)uracil showed powerful inhibition.

The development of new non-nucleoside reverse transcriptase inhibitors (NNRTIs) is an efficient strategy for finding new therapeutic agents against human immunodeficiency virus (HIV). A large number of 6-substituted uracil derivatives have been prepared in order to explore new NNRTIs. However, there are few approaches to anti-HIV agents from 1,3-disubstituted uracil derivatives. Therefore, we tried to prepare several 1,3-disubstituted uracils, which were easily obtainable from uracil by preparation under alkali and Mitsunobu conditions, and examined their antiviral activity against HIV-1 and human cytomegalovirus (HCMV). We found that 1-benzyl-3-(3,5-dimethylbenzyl)uracil and 1-cyanomethyl-3-(3,5-dimethylbenzyl)-4-thiouracil showed powerful inhibition against HCMV and HIV-1, respectively.

A new method to introduce a benzyl group onto the 2'-OH of purine ribonucleoside is described. Thus, 6-chloropurine 3'-O-benzoylriboside and its 5'-O-trityl congener were condensed with benzyl alcohol using the Mitsunobu reaction to give the 2'-O-benzyl derivative. The yields were varied from 4.6 to 62.9% depending on the solvent. The product was converted to adenosine, indicating that the stereochemistry at C-2' is retained.

Two industrial synthetic approaches to Lodenosine (1, FddA, 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl) adenine) via a purine riboside or a purine 3'-deoxyriboside are described. Several novel applications of deoxygenation and fluorination methods are compared considering reaction yields, economy, safety and environmental concerns.

A new method to introduce a benzyl group onto the 2'-OH of purine ribonucleoside is described. Thus, 6-chloropurine 3'-O-benzoylriboside and its 5'-O-trityl congener were condensed with benzyl alcohol using the Mitsunobu reaction to give the 2'-O-benzyl derivative. The yields were varied from 4.6 to 62.9% depending on the solvent used. The product was converted to adenosine, indicating that the stereochemistry at C-2' is retained.

N3-Phenacyl-N1-substituted uracils 3a-q were synthesized by introduction of substituents at the N1-position of N3-phenacyluracil 2, and their hypnotic and sedative activities were evaluated. Pharmacological activities of these N3-phenacyl-N1-substituted uracils were examined using hypnotic activity and synergistic effects with pentobarbital or diazepam for the hypnotic and sedative activities.

The protected analogue of 2-amnio-6-chloropurine arabinoside (3b) was subjected to reaction with diethylaminosulfur trifluoride (DAST) and subsequently treated with NaOAc in Ac2O/AcOH to give N2, O3', O5'-triacetyl-2'-deoxy-2'-fluoroguanosine (5a). After deacetylation of the sugar moiety and protection of 5'-OH by a 4,4'-dimethoxytrityl group, this nucleoside component was converted to 2'-deoxy-2'-fluoroguanyl-(3',5')-guanosine (6c, GfpG).

Reaction of tri-O-acetyluridine (1) with benzyl bromide or 2-chloroacetophenone in the presence of K2CO3 gave the N3-substituted analogues 2a,c. Condensation of 1 with (+/-)-1-phenylethanol or 3,5-dimethylbenzyl alcohol using the Mitsunobu reaction also gave 2b,d in good yields. These compounds were allowed to react with Lawesson's reagent and were subsequently treated with ammonia to afford the 4-thiouracil derivatives 5a-d. Compounds 5a-c showed moderate hypnotic activity in mice. However, N3-(3,5-dimethyl)benzyl derivatives 3d, 5d were found to be almost inactive in this assay.

Peracetylated guanosine was reacted with POCl3 to give an 2-acetamido-6-chloro-9H-purine derivative, which was condensed with primary or secondary alcohols to give N2-alkylated analogues. The products were treated with mercaptoethanol in the presence of sodium methoxide to afford N2-alkylguanosines.

Peracetylated guanosine was reacted with POCl3 to give an 2-acetamido-6-chloro-9H-purine derivative, which was condensed with primary or secondary alcohols to give N2-alkylated analogues. The products were treated with mercaptoethanol in the presence of sodium methoxide to afford N2-alkylguanosines.

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.

A general procedure to obtain tetra-substituted uric acid by stepwise N-alkylation is described. 2,6-Dichloropurine (1) was condensed with 1-propanol by Mitsunobu reaction to give 9-propyl congener (2). Treatment of 2 with ammonia gave adenine derivative (4a), which was converted to the 8-oxoadenine (5b) in 3 steps. Methylation of 5b proceeded site-specifically to give 6-amino-2-chloro-7,8-dihydro-7-methyl-9-propylpurin-8-one (6) as a sole product. Compound 6 was successively treated with NaNO2 and iodomethane to give 2-chloro-1,6,7,8-tetrahydro-1,7-dimethyl-9-propylpurin-6,8-dione (9) accompanied by the O6-methyl product (8) in 75% and 6.9%, respectively. After nucleophilic substitution of 9 with NaOAc, the product (11) was reacted with iodomethane to give the uric acid (12) and the 2-methoxy product (13) in 46% and 15.5%, respectively. However, the reaction of 11 with the benzylating agents gave only O-benzyl products (14a,b).