Pyrimidine non-nucleoside analogs: A direct synthesis of a novel class of N-substituted amino and N-sulfonamide derivatives of pyrimidines

A convenient method for the regioselective synthesis of pyrimidine non-nucleoside analogs was developed. This study reports a novel and efficient method for the synthesis of a new type of N-substituted amino methylsulfanylpyrimidines and the corresponding pyrazolo[3,4-d]pyrimidines. This series of compounds was designed through the reaction of dimethyl N-cyanodithioiminocarbonate with 2-cyano-N'-(thiophen-2-yl-, furan-2-yl- and pyridin-4-ylmethylene)acetohydrazide and N'-(2-cyanoacetyl)arylsulfonohydrazides. The scope and limitation of the method are demonstrated. The antibacterial and antifungal activities of the synthesized compounds were also evaluated.

Nucleic acid components and their analogs: Design and synthesis of novel cytosine thioglycoside analogs

The synthesis of a new category of novel cytosine 4-thioglycoside analogs has been first accomplished. The main step of this strategy is the synthesis of sodium pyrimidine-4-thiolate through the condensation of 2-cyano-N-arylacetamides with sodium cyanocarbonimidodithioate, followed by coupling with α-bromo-sugars to afford the corresponding cytosine 4-thioglycoside analogs. The free thioglycosides were also prepared. Subsequent studies on the application of this strategy for the preparation of other potent pyrimidine thioglycosides are reported.

Crystal structure of (E)-2-amino-4-methyl-sulfanyl-6-oxo-1-{[(thiophen-2-yl)-methyl-idene]-amino}-1,6-di-hydro-pyrimidine-5-carbo-nitrile

The title compound, C11H9N5OS2, a 1-thio-phen-2-yl-methyl-ene-amino-pyrimidine derivative, displays an essentially planar C-NH2 group. The conformation across the N=C bond linking the pyrimidine and thienyl groups is E. The pyrimidine and thienyl ring systems subtend an inter-planar angle of 42.72 (5)°. In the crystal, mol-ecules are linked by N-H⋯Nnitrile and N-H⋯O=C hydrogen bonds, forming chains parallel to the b axis.

Inhibition of intestinal motility by methanol extracts of Hibiscus sabdariffa L. (Malvaceae) in rats

The methanol extracts of Hibiscus sabdariffa (p < 0.01) showed a significant dose dependent relaxant effect (IC50) = 350 microM) on rat ileal strip comparable to the effect shown by nifedipin and papaverine as reference compounds. Similarly, the extract when administered intraperitoneally significantly (p < 0.05-0.01) reduced the intestinal transit (13%-35%) in rats (IC50, = 250 microM). The extracts (40% +/- 04%) and nifedipin (51% +/- 05%) also potentiated the diarrhoea inducing effect of castor oil (IC50 = 350 microM). It is postulated that these effects are possibly generated by constituents such as quercetin and eugenol via a Ca2+ channel modulated mode of action.

Estrogenic and cholinergic properties of the methanol extract of Ruellia praetermissa Sceinf. ex. Lindau (Acanthaceae) in female rats

In search for alternative drugs with pharmacological profile to replace hormone replacement therapy, the effects of MeOH extract of Ruellia praetermissa on the uterus and gestation in rats was investigated. 350 mg/kg/day of extract from days 1-9, 1-17 and 9-17 respectively, resulted in increase of the number of implantation sites (56 to 64) and the percentage of implantation (68.6 +/- 2.7 to 90.5 +/- 0.5%). There was also an increase in body weight (1-9 and 1-17) followed by a slight decrease (154 +/- 15.5 to 125 +/- 10) in the body weight at term. The number and the mean value of corpora lutea per female decreased from 25.4 +/- 1.6 to 14.00 +/- 1.6. The extract produced dose-related contraction of the isolated uterine muscle in vitro comparable to ACh. Atropine in doses from 3.4 x 10(-6) to 3 x 10(-3) microM antagonized the response of the uterus to ACh at 2 microM. It induced an increase (0.03 +/- 0.002 to 0.34 +/- 0.001 g) of the uterine weight comparable to that produced by using 3 microM estradiol (0.03 +/- 0.001 to 0.35 +/- 0.005 g). It could therefore be postulated that this extract possesses estrogenic and possible cholinergic effects. The estrogenic effect could have been generated by plant sterols (beta-sitosterol and stigmasterol) and flavonoids (luteolin and apigenin) while cholinergic effect could be due to iridoid glycosides.

In vitro purgative effect of Ruellia praetermissa. Sceinf.ex.Lindau (Acanthaceae)

Methanol, ethylacetate and aqueous extracts of Ruellia praetermissa initiated spontaneous contractions in the quiescent and increased contraction on the electrically stimulated ileal strip at a concentration of 30 microg/ml. The extracts produced concentration-related contractions both in amplitude and tone up till 750 microg/ml with IC(50) of 360 microg/ml (methanol extract), 425 microg/ml (ethylacetate extract) and 540 microg/ml (aqueous extract). Acetylcholine also produced a concentration-related (IC(50)=18 microg/ml) contractions of the isolated ileum. Atropine in concentrations of 3.4 x 10(-6)-3 x 10(-3) microg/ml antagonized progressively the response of the isolated ileum to acetylcholine (32 x 10(-2) microg/ml) and the methanol extract (650 microg/ml) induced contractions suggesting a mode of action via cholinergic system. Luteolin and apigenin and iridoid glucosides (taxiphilin and 8-epi-deoyganic acid) might be responsible at least in part for the observed effect.

Mineral composition of renal stones from the Sudan

Urolithiasis is a very frequent finding in the Sudan, but stone analysis is not routinely performed in this country. It would, however, give important evidence for the metabolic basis of stone formation. We therefore set out to analyze urinary stones in 80 Sudanese patients (45 male, 35 female), 12 of whom where children. Fourier-transformed infrared spectroscopy was used for stone analysis. As is known from other countries, calcium oxalate (CaOx) stones were the most frequent, with 68.7% of all stones in adults and 43.7% of childhood stones. Uric acid and uric acid dihydrate stones were more often seen in adults (13.2%) than in children (4. 1%). Ammonium urate stones are common in the Sudan, especially in children (32.9%), which is typical for underdeveloped countries. Infectious stones (struvite and carbonate apatite) were more often found in women (7.0%) and in children (5.3%) than in men (1.4%). Brushite stones were seldom seen and cystine stones did not occur.

N-acetyl-beta-D-glucosaminidase excretion in healthy children and in pediatric patients with urolithiasis

Hyperoxaluria was reported to induce renal damage, probably due to toxic effects on renal tubules. Such tubular damage might be expressed by an increase in urinary excretion of marker enzymes such as N-acetyl-beta-D-glucosaminidase (NAG). We set out to examine a possible relationship between the excretion of NAG and that of urinary lithogenic and stone-inhibitory substances by analyzing 24-h urine specimens from 56 children with urolithiasis and 25 healthy children with normal renal function and without a history of urolithiasis. The NAG excretion was higher in patients with urolithiasis (3.5 +/- 0.51 U/g creatinine) as compared with healthy subjects (1.33 +/- 0.14 U/g creatinine, P < 0.05). A positive correlation between NAG and oxalate excretion was observed in female patients (r = 0.56: P < 0.01). In conclusion, the increase in urinary NAG in children with urolithiasis might express renal tubular damage. It seemed, however, not to be specifically related to the excretion of a single lithogenic substance.

Synthesis of novel thieno[2,3-d]pyrimidine, thieno[2,3-b]pyridine and thiazolo[3,2-a]thieno[2,3-d]pyrimidine derivatives and their effect on the production of mycotoxins

The thiophene derivative 1 reacts with the active methylene reagents 2a-c to afford the thieno[2,3-d]pyrimidine derivatives 6a,b and 8, respectively. 1 reacts with phenacyl bromide 2d to afford the N-alkylation product 9 and reacts with phenacyl thiocyanate 2e to afford the N-(thiazol-2-yl) derivative 10, which was further cyclized into thiazolo[3,2-a]thieno[2,3-d]pyrimidine derivative 12. Compound 1 reacts also with the cinnamonitriles 3a,b to afford the thieno[2,3-b]pyridines 15a,b, respectively. 1 undergoes either acetylation or hydrolysis to afford the thieno[2,3-b]pyridine derivative 19 and the thiophene derivative 22, respectively. Some of the new compounds show inhibitory effect to the production of mycotoxins and to fungal growth.