Oxidative cyclization of D-fructose thiosemicarbazones to 2-amino-5-(D-arabino-1,2,3,4-tetrahydroxybut-1-yl)-1,3,4-thiadiazoles through carbon-carbon bond cleavage of the sugar chain.

Condensation of D-fructose (1) with thiosemicarbazide or 4-phenylthiosemicarbazide gave the corresponding D-fructose thiosemicarbazones (3a and 3b). The latter compounds underwent oxidative cyclization with 10% ethanolic ferric chloride to give mixtures of 2-amino-5-(D-arabino-1,2,3,4-tetrahydroxybut-1-yl)-1,3,4-thiadiazole (6a) and 2-amino-5-hydroxymethyl-1,3,4-thiadiazole (5a) from 3a and the corresponding 2-phenylamino compounds 6b and 5b from 3b. These products were formed as a result of cyclization of the thiosemicarbazone entity accompanied by C-1-C-2 or C-2-C-3 bond cleavage of the sugar chain. Structures of the 1,3,4-thiadiazole acyclo C-nucleosides 6a and 5b were confirmed by comparison with the unequivocally prepared compounds obtained by the dehydrogenative cyclization of D-arabinose thiosemicarbazones 11a and 11b with ethanolic ferric chloride. Structures of the 5-hydroxymethyl-1,3,4-thiadiazoles 5a and 5b were also confirmed by comparison with 5a and 5b unequivocally prepared by periodate cleavage of the alditolyl chain of 6a and 6b followed by reduction of the resulting aldehydes 8a and 8b with sodium borohydride. Compounds 6a and 6b were further characterized as their acetates 7a and 7b and were found to exist in the extended planar zizag conformation 13. Condensative cyclization of the D-arabinose thiosemicarbazones 11a and 11b by boiling with acetic anhydride afforded the 1,3,4-thiadiazoline acyclo C-nucleoside acetates 9a and 9b which exist in the sickle (bent) conformation 14. De-N- and de-O-acetylation with concomitant aromatization of 9a and 9b with 10% ethanolic FeCl3 gave the 1,3,4-thiadiazole acyclo C-nucleosides 6a and 6b. The assigned structures were corroborated by 2D 1H-1H HOMCOR and 2D 1H-13C HETCOR NMR spectroscopy.

Reexamination of some reactions of 3-(D-galactosylidenehydrazino)-1,2,4-triazino[5,6-b]indole.

Incorrect structures described in the literature for the products of reactions of the title compound 6 were reexamined and corrected. Thus, the product of acetylation of 6 with acetic anhydride in the presence of pyridine was found to be the mono-N-penta-O-acetyl derivative 10 and not the previously described di-N-penta-O-acetyl derivative 7. Assignment of structure 10 was based on 1H NMR data as well as its ability to undergo oxidative cyclization with Br2/AcOH to give 12. The previously assigned structure 7 would be incapable of undergoing such cyclization. The linear structure 12 rather than the angular regioisomer 3c was assigned on the basis of its UV absorption pattern and 1H NMR NOE spectra. Attempted preparation of 7 by increasing the duration of the reaction gave only compound 10. A di-N-acetyl-penta-O-acetyl derivative, however, was obtained with acetyl bromide in the presence of pyridine to which structure 8 rather than structure 7 or 9 was assigned on the basis of 1H NMR NOE studies. Acetylation of the triazolo-triazino-indole 11 gave a product identical to 12; structure 15 previously assigned to this product is, therefore, in error. Finally, the angular annelated structure 3e previously ascribed to the oxidative cyclization product of the 5-methylhydrazone congener of 6 (13) is now rectified to the linear annelated structure 14; the latter was found to be identical to the product obtained by N-methylation of the unequivocally linear 1,2,4-triazolo[4,3-b]1,2,4-triazino[5,6-b]indole 11. Compound 8 was found to exist in the preponderantly populated sickle (bent) conformation 18 in contrast to compounds 10 and 12 which were found to adopt the extended planar zigzag conformations 19 and 20 respectively.

Antibacterial activity of chitosan against Aeromonas hydrophila.

The effect of chitosan on growth and production of haemolysin by Aeromonas hydrophila was investigated as well as the effects of temperature, pH, salts and irradiation on the antibacterial activity of chitosan. It was found that chitosan affected growth and haemolysin production of A. hydrophila in varying degrees compared to the control. Growth and haemolysin production were clearly suppressed at 0.04% of chitosan. Suppression was more effective at pH 6.0 than at pH 7.0. The bactericidal effects of chitosan increased with increasing temperature and decreasing pH. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Sodium ions at concentrations of 10 and 25 mM also reduced chitosan's activity. Irradiation of chitosan at 150 kGy under dry condition was effective in slightly increasing its activity.

Reinvestigation of the regiospecific outcome of heterocyclization of 3-hydrazino-1,2,4-triazino[5,6-b]indoles: angular versus linear annelated 1,2,4-triazolo-1,2,4-triazino[5,6-b]indole structures.

Divergences of the structural assignments reported in the literature for the products of cyclization of 3-hydrazino-1,2,4-triazino[5,6-b]indoles 1 with one-carbon cyclizing reagents have been reinvestigated. The linear annelated 1,2,4-triazolo[4,3-b]1,2,4-triazino[5,6-b]indoles 3 were found to be the products regiospecifically formed, rather than the angular annelated 1,2,4-triazolo[3,4-c]1,2,4-triazino[5,6-b]indoles 2. Our findings were based on comparison of the UV spectral data of the cyclization products with those of unequivocally as well as inevitably linear annelated compounds. Calculations of optimized geometries and electronic structures accord with the results obtained. Divergences reported in the literature were, therefore, attributed to erroneous structural assignments rather than to cyclization by different regiochemical pathways.

Effective control of hookworm infection in school children from Dhofar, Sultanate of Oman: a four-year experience with albendazole mass chemotherapy.

After 4 years of mass chemotherapy with a single annual dose of albendazole 400 mg, health education and promotion of environmental health, the prevalence of Necator americanus in Wilayat Tagah, Dhofar, Oman was reduced from 40 to 1.3% and from 6 to 0%, respectively, among rural and urban school children. Stool samples with egg load >1000 egg/gm were reduced from 28 to 0% after the first year of intervention and maintained as such in subsequent years.

Synthesis and antimicrobial activity of acyclo C-nucleosides: 3-(alditol-1-yl)-7-oxo-5-phenyl-1,2,4-triazolo[4,3-a]pyrimidines.

Condensation of 2-hydrazino-4-oxo-6-phenylpyrimidine (1) with aldopentoses 2a-d or aldohexoses 2e-g gave the corresponding aldehydo-sugar (4-oxo-6-phenylpyrimidin-2-yl)hydrazones 3a-g which were acetylated to the corresponding poly-O-acetyl-aldehydo-sugar (3-acetyl-4-oxo-6-phenylpyrimidin-2-yl)hydrazones 4a-g. The latter compounds underwent oxidative cyclization with bromine in acetic acid and in the presence of sodium acetate to the corresponding 8-acetyl-3- (poly-O-acetyl-alditol-1-yl)-7-oxo-5-phenyl-1,2,4-triazolo[4,3-a]pyrimid ines 6a-g. Compounds 6a-g were also obtained by consecutive one-pot oxidative cyclization/acetylation in which the parent hydrazones 3a-g were treated with bromine/acetic acid/sodium acetate followed by acetic anhydride. Deacetylation of 6a-g with ammonium hydroxide in methanol gave the title compounds 7a-g. The antibacterial and antifungal activities of compounds 3c, 3f, 7c and 7f are reported.

Sterically controlled regiospecific heterocyclization of 3-hydrazino-5-methyl-1,2,4-triazino[5,6-b]indole to 10-methyl-1,2,4-triazolo[4',3':2,3[1,2,4-triazino[5,6-b]indoles.

3-Hydrazino-5-methyl-1,2,4-triazino[5,6-b]indole underwent sterically controlled regiospecific heterocyclizations with a variety of one-carbon cyclizing agents to give the sterically more favored linearly annulated 10-methyl-1,2,4-triazolo[4',3':2,3[1,2,4-triazino[5,6-b]indoles rather than the sterically less favored angularly annulated 10-methyl-1,2,4-triazolo[3',4':3,4]1,2,4-triazino[5,6-b]indoles. The assigned structures were corroborated by comparison with unequivocally synthesized authentics, chemical and spectral data. The antimicrobial activity of some of the prepared compounds was investigated.

Triplet pregnancy and delivery after intracytoplasmic injection of round-headed spermatozoa.

Intracytoplasmic sperm injection (ICSI) of round-headed spermatozoa into mature oocyte resulted in normal fertilization, embryo development and pregnancy in a 28 year old female. The husband had a long history of primary infertility. Three ICSI attempts were carried out and fertilization and embryo development occurred in all trials. However, only the third trial led to a pregnancy, which proved to be quadruplet after the transfer of four embryos. One embryo vanished and the remaining triplets were delivered at 35 weeks of gestation by Caesarean section. Two of the babies, a boy weighing 2000 g and a girl weighing 2250 g at birth were discharged in a good condition 1 week after delivery and the third baby, a boy weighing 1550 g, was discharged 3 weeks after delivery.

Synthesis of acyclo-C-nucleosides: 2-(alditol-1-yl)-5-methylthio- and -5-benzylthio-1,3,4-thiadiazoles.

Condensation of S-methylhydrazinecarbodithioate or S-benzylhydrazinecarbodithioate with aldopentoses or aldohexoses gave the corresponding aldehydo-sugar S-methylhydrazonecarbodithioates of S-benzylhydrazonecarbodithioates. Oxidative cyclization of these hydrazones with bromine in acetic acid gave the corresponding 2-(alditol-1-yl)-5-alkylthio-1,3,4-thiadiazoles. Acetylation of the latter gave the corresponding per-O-acetyl derivatives which were also obtained by one-pot preparation by treatment of the hydrazones with bromine and sodium acetate in acetic acid followed by acetic anhydride. Some of the prepared compounds were tested for antimicrobial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Candida albicans. While hydrazones showed significant activity against these organisms, the thiadiazoles were devoid of antimicrobial activity.

Schistosomiasis in the southern region of Oman: vector snails and serological identification of patients in several locations.

The snail Biomphalaria arabica is apparently ubiquitous in the south of Oman (Dhofar province). Snails bred in the laboratory were susceptible to infection with miracidia of Schistosoma mansoni (Puerto Rican strain). The snail Bulinus wrighti, a potential intermediate host of S. haematobium, was found for the first time in Dhofar. Human sera from five localities had antibodies against adult worm antigens and in particular against Sm31/32. The prevalence of seropositive patients was 28% of 47 farm workers, 12% of 99 out-patients from a clinic and 1% of 389 children from four localities. Autochthonous transmission of schistosomiasis in Dhofar is discussed.

Reactions of 4-aryl-1-hydrazinophthalazines with carbonyl compounds.

Reaction of 1-hydrazino-4-phenylphthalazine and 4-benzyl-1-hydrazinophthalazine with different carbonyl compounds are described. With oxalic acid, the two cyclic amidrazones reacted to give 6-aryl-1,2,4-triazolo[3,4-a]phthalazines. Reaction with diethyl oxalate, however, afforded the corresponding 7-aryl-3,4-dioxo-1,2,4-triazino[3,4-a]phthalazines. With pyruvic acid, ethyl pyruvate, or methyl phenyl glyoxylate the corresponding hydrazones were obtained which were cyclized to 7-aryl-3-methyl or 7-aryl-3-phenyl-1,2,4-triazino[3,4-a]phthalazines, respectively. Whereas the reaction of the two cyclic amidrazones with acetylacetone or ethyl phenyl propiolate gave pyrazole derivatives, their reaction with ethyl acetoacetate gave 6-aryl-3-methyl-1,2,4-triazolo[3,4-a]phthalazines. The results of biological testing of representative examples of the prepared compounds as insecticides and nematicides are reported.

2-bromo-alpha-ergocryptine mesylate (CB-154) inhibits prolactin and luteinizing hormone secretion in the prepubertal female rat.

Treatment of immature female rats with 100 micrograms 2-bromo-alpha-ergocryptine mesylate (CB-154) per ml drinking water beginning on Day 30 of age until vaginal opening delayed puberty by 6 days. Rats treated with CB-154 exhibited vaginal opening at 43.3 +/- 0.6 days whereas controls exhibited vaginal opening at 37.9 +/- 0.8 days. Most interestingly, serum levels of luteinizing hormone (LH) and prolactin (PRL) on Days 31-35, determined by a homologous radioimmunoassay were significantly lower in treated rats than in controls. The ovarian concentrations of progesterone (P) and androstenedione (A) were lower in rats treated with CB-154 than in controls; ovarian estradiol (E2) concentrations were low in both groups. Serum levels of P (but not A and E2) were reduced on Days 31-35 of the treatment period. Cessation of the CB-154 treatment on the morning of Day 35 returned the onset of puberty to normal values; steroid and gonadotropin levels also returned to normal values within 2 days after removal of the CB-154 from the drinking water. Near the time of onset of puberty, serum levels of LH in rats treated with CB-154 returned to control values. These data indicate that in the female rat the delay in puberty induced by CB-154 might be due to a reduction in the secretion of LH, especially since the onset of delayed puberty in rats treated with CB-154 correlates with an increase in the serum level of LH. Further studies are needed to elucidate the specific effects of hypoprolactinemia on ovarian function and the onset of puberty in the rat.

Luteinizing hormone increases the number of ova shed in the cyclic hamster and guinea-pig.

Osmotic minipumps containing 400 micrograms ovine LH installed subcutaneously on day 1 (oestrus) of the cycle in the hamster induced superovulation of 30.0 +/- 2.1 ova (n = 5) at the next expected oestrus. Controls ovulated 12.0 +/- 0.8 ova (n = 6). Bovine LH, human LH, porcine LH, human chorionic gonadotrophin and pregnant mare serum gonadotrophin were effective in approximately doubling the number of ova spontaneously shed in the hamster. Ovine FSH (200 micrograms/pump) was most effective in increasing the number of ova spontaneously shed (55 +/- 6, n = 5) in the hamster. Infusion of ovine LH on days 1-4 prevented the reduction of the number of antral follicles that occurs normally between days 3 and 4 of the 4-day cycle. Since this reduction in follicular numbers in control cyclic hamsters is due to atresia, the exogenous LH might prevent atresia of the developing follicles. In the hamster, exogenous ovine LH significantly increased the serum concentrations of androstenedione, oestradiol and LH but not of FSH. Hamsters were hypophysectomized on the day of oestrus, given immediate LH (400 micrograms) or FSH (200 micrograms) replacement therapy and autopsied on day 4. Ovarian histology revealed that immediate LH treatment after hypophysectomy sustained development of histologically normal preovulatory follicles but had no effect on the number of smaller sizes of follicles. Immediate FSH treatment after hypophysectomy increased only the number of smaller sized follicles. Since LH did not increase the smaller sized follicles, no 'FSH-like' effect on follicular development was observed. In the hamster, the ability of various preparations of LH to induce superovulation did not correlate with their ability to displace 125I-labelled ovine FSH from its ovarian binding sites. The superovulatory action of LH required the presence of the pituitary gland, indicating that LH might synergize with FSH and/or prolactin (or hamster LH) for spontaneous superovulation and it appears that exogenous LH might induce superovulation by prevention of atresia. Infusion of LH into the guinea-pig beginning on day 12 of the cycle (day 1 is the day of ovulation) doubled the ovulation rate whereas in the cyclic rat and mouse LH treatment throughout the cycle was ineffective in increasing the number of ova shed.

Synthesis of 2-acetamido-2-deoxy-3-O-beta-D-mannopyranosyl-D-glucose.

Condensation of 4,6-di-O-acetyl-2,3-O-carbonyl-alpha-D-mannopyranosyl bromide with benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-alpha-D-glucopyranoside (2) gave an alpha-D-linked disaccharide, further transformed by removal of the carbonyl and benzylidene groups and acetylation into the previously reported benzyl 2-acetamido-4,6-O-benzylidene groups and acetylation into the previously reported benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl)-alpha-D-glucopyranoside. Condensation of 3,4,6-tri-O-benzyl-1,2,-O-(l-ethoxyethylidene)-alpha-D-glucopyranose or 2-O-acetyl-3,4,6-tri-O-benzyl-alpha-D-glucopyranosyl bromide with 2 gave benzyl 2-acetamido-3-O-(2 O-acetyl-3,4,6-tri-O-benzyl-beta-D-glucopyranosyl)-4,6-O-benzylidene-2-deoxy-alpha-D-glucopyranoside. Removal of the acetyl group at O-2, followed by oxidation with acetic anhydride-dimethyl sulfoxide, gave the beta-D-arabino-hexosid-2-ulose 14. Reduction with sodium borohydride, and removal of the protective groups, gave 2-acetamido-2-deoxy-3-O-beta-D-mannopyranosyl-D-glucose, which was characterized as the heptaacetate. The anomeric configuration of the glycosidic linkage was ascertained by comparison with the alpha-D-linked analog.

The synthesis of 2-acetamido-2-deoxy-4-O-beta-D-mannopyranosyl-D-glucose.

Condensation of 4,6-di-O-acetyl-2,3-O-carbonyl-alpha-D-mannopyranosyl bromide with 2-amino-2-N,3-O-carbonyl-5.6-O-isopropylidene-D-glucose diethyl acetal gave, unexpectedly, 2-amino-2-N,3-O-carbonyl-2-deoxy-4-O-(4,6-di-O-acetyl-2,3-O-carbonyl-alpha-D-mannopyranosyl)-5,6-O-isopropylidene-D-glucose diethyl acetal, futher transformed, by de-esterification followed by acetylation, into the previously known 2-amino-2-N,3-O-carbonyl-2-deoxy-5,6-O-isopropylidene-4-O-alpha-D-mannopyranosyl-D-glucose diethyl acetal and its tetra-O-acetyl derivative. Benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside was condensed with 2-O-acetyl-3,4,6-tri-O-benzyl-beta-D-glucopyranosyl bromide to give benzyl 2-acetamido-4-O-(2-O-acetyl-3,4,6-tri-O-benzyl-beta-D-glucopyranosyl)-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside. Removal of the 2-O-acetyl group, followed by oxidation with acetic anhydridedimethyl sulfoxide, gave a beta-D-arabino-hexosid-2-ulose (25). After reduction with sodium borohydride, removal of the benzyl groups gave crystalline 2-acetamido-2-deoxy-4-O-beta-D-mannopyranosyl-D-glucose (27). The anomeric configuration of the glycosidic linkage was ascertained by comparison with the alpha-D-linked disaccharide.

The synthesis of 2-acetamido-2-deoxy-6-O-beta-D-mannopyranosyl-D-glucose.

4,6-Di-O-acetyl-2,3-O-carbonyl-alpha-D-mannopyranosyl bromide was condensed with benzyl 2-acetamido-3,4-di-O-acetyl-2-deoxy-alpha-D-glucopyranoside in the presence of silver carbonate to give crystalline benzyl 2-acetamido-3,4-di-O-acetyl-2-deoxy-6-O-(4,6-di-O-acetyl-2,3-O-carbonyl-beta-D-mannopyranosyl)-alpha-D-glucopyranoside in 32% yield. Removal of the protective O-acetyl and cyclic carbonate groups gave the crystalline benzyl alpha-glycoside of the disaccharide, which was catalytically hydrogenolyzed to yield the crystalline, title compound. Proof of the anomeric configuration of the interglycosidic linkage was obtained by comparison of the physical, spectral, and chromatographic properties of the disaccharide and its derivatives with those of the previously prepared alpha-D-linked analog.

The synthesis of glycopeptide fragments of human plasma alpha1-acid glycoproteins by sequential elongation at the terminal-amino group.

Glycopeptides corresponding to sequences 27--28, 48--49, and 58--59 of human plasma alpha1-acid glycoproteins have been synthesized by sequential elongation of the peptide chain at the terminal amino group. 2-Acetamido-3,4,6-tri-O-acetyl-1-N-(L-aspart-4-oyl)-2-deoxy-beta-D-glucopyranosylamine was condensed with the p-nitrophenyl esters of protected amino acids to give the corresponding protected glycodipeptides having the sequences Gly-(GlcNAc-4-)Asn, Pro-(GlcNAc-4-)Asn, Val-(GlcNAc-4-)Asn, Leu-(GlcNAc-4-)Asn, Glu-(GlcNAc-4-)Asn, Tyr-(GlcNAc-4-)Asn, Ser-(GlcNAc-4-)Asn, and Cys-(GlcNAc-4-)Asn. Deprotection of the carbohydrate and of the peptide residues of these compounds was achieved, except for those having N-tert-butyloxycarbonyl protective groups, to give the corresponding free glycopeptides. The glycotripeptide 2-acetamido-1-N-(2-N-[N-(tert-butyloxycarbonyl)-L-glutam-1-oyl-L-tyrosyl]-L-aspart-4-oxy)-2-deoxy-beta-D-glucopyranosylamine, having the amino acid sequence 10--12 of human plasma alpha1-acid glycoprotein, was prepared by condensation of 2-acetamido 3,4,6-tri-O-acetyl-2-deoxy-1-N-[2-N-(L-tyrosyl)-L-aspart-4-oyl[-beta-D-glucopyranosylamine with 5-benzyl 1-p-nitrophenyl N-(tert-butyloxycarbonyl)-L-glutamate, followed by removal of the ester groups.