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Immunomodulation by the new synthetic thiazole derivative tiprotimod. 2nd communication: immunopharmacological activity.

The thiazole derivative [2-(3-carboxy-1-propylthio)-4-methyl-1,3-thiazole] acetic acid (tiprotimod, HBW 538) a new synthetic immunopotentiator of low molecular weight, has been tested in vivo and ex vivo in various experimental models. Its influence on parameters of macrophage functions, on DTH (delayed type hypersensitivity)-reaction and antibodies to sheep erythrocytes (SRBC), Tetanus toxoid and heatkilled E. coli bacteria in mice, and in the popliteal lymph node assay in rats was investigated. When mice were treated with the test substance i.v., i.p., or p.o. in a dose range from 1-100 mg/kg, a time and dose-dependent stimulation of macrophage activity was observed. The drug was able to enhance the DTH-response against SRBC and to stimulate the humoral immune response against Tetanus toxoid and heat-killed E. coli. In the popliteal lymph node assay, a murine graft-vs-host model, a stimulating effect of the substance was observed when it was administered at the same time of the grafts to rats. These results demonstrate that tiprotimod is a potent immunopotentiator for both humoral and cell mediated immune response in experimental animals.

Adjuvants, Immunologic↗

Immunomodulation by the new synthetic thiazole derivative tiprotimod. 1st communication: synthesis and structure-activity relationships.

A series of carboxyalkylthio-substituted thiazole-carboxylic acids was synthesized and examined for macrophage activation and stimulation of the DTH (delayed type of hypersensitivity)-reaction. The structure-activity relationship in this series of new immunomodulators is discussed. Broadest immunological activity was seen for [2-(3-carboxy-1-propylthio)-4-methyl-1,3-thiazole]acetic acid (tiprotimod, HBW 538) which was selected for further studies.

Animals↗

Biosynthesis of thiamin. Different biosynthetic routes of the thiazole moiety of thiamin in aerobic organisms and anaerobic organisms.

The nitrogen atom of glycine was incorporated into the thiazole moiety of thiamin in the aerobic microorganisms Bacillus subtilis, Pseudomonas putida, Saccharomyces cerevisiae, Mucor racemosus, Neurospora crassa, and Emericella nidulans. It was not incorporated in the case of the facultative anaerobic microorganisms Escherichia coli and Enterobacter aerogenes, which, however, did incorporate the nitrogen atom of tyrosine. These results show that aerobic microorganisms and facultative anaerobic microorganisms have different biosynthetic pathways for the thiazole moiety of thiamin.

Bacteria↗

Prevention of spontaneous polyarthritis in NZB/KN mice by treatment with a novel thiazole derivative, SM-8849.

NZB/KN mice spontaneously develop polyarthritis, characterized by infiltration of inflammatory cells into the synovium and destructive damage of articular cartilage and bone. This study was performed to elucidate the effects of a novel thiazole derivative (SM-8849; (4-[1-(2-fluoro-4-biphenylyl)-ethyl]-2-methylamino thiazole) in comparison with the cyclooxygenase inhibitor, indomethacin, on disease development and immune disorders in NZB/KN mice. Mice were treated with SM-8894 (50 mg/kg) or indomethacin (2 mg/kg), starting from two months of age, for seven months. Indomethacin had no inhibitory effect on joint lesions in this model. In contrast, SM-8849 was effective in arresting the progression of arthritis, as confirmed by histologic and radiographic studies. Moreover, SM-8849, but not indomethacin, suppressed rheumatoid factor production. In addition, the population of CD5+ B cells in the peritoneal cavity and spleen was reduced with SM-8849 treatment. These findings suggest that NZB/KN mice are of use in the evaluation of intrinsic antiarthritic activity, independently of cyclooxygenase inhibition. Additionally, the therapeutic value of SM-8849 is strongly suggested by its efficacy in this model.

Animals↗

In vitro and in vivo characterization of the dopamine D4 receptor, serotonin 5-HT2A receptor and alpha-1 adrenoceptor antagonist (R)-(+)-2-amino-4-(4-fluorophenyl)-5-[1-[4-(4-fluorophenyl)-4-oxobutyl] pyrrolidin-3-yl]thiazole (NRA0045).

(R)-(+)-2-Amino-4-(4-fluorophenyl)-5-[1-[4-(4-fluorophenyl)-4-oxobutyl]+ ++pyrrolidin-3-yl]thiazole (NRA0045), a novel thiazole derivative, has high affinities for the human cloned dopamine D4.2, D4.4 and D4.7 receptors, with Ki values of 2.54, 0.55 and 0.54 nM, respectively. NRA0045 is approximately 91-fold more potent at the dopamine D4.2 receptor, compared with human cloned dopamine D2L receptor. NRA0045 also has high affinities for the serotonin (5-HT)2A receptor (Ki = 1.92 nM) and alpha-1 adrenoceptor (Ki = 1.40 nM) but weak affinities (IC50 values are approximately 1 microM) for six other neurotransmitter receptors (adenosine1, 5-HT1A, 5-HT1C, dopamine transporter, alpha2A and alpha2A) and negligible affinities (IC50 values are over 10(-5) M) for 42 other receptors, including neurotransmitters and hormones, ion channels and second messenger systems. Locomotor hyperactivity induced by methamphetamine (1 mg/kg i.p.) in mice was dose-dependently antagonized by NRA0045 (ED50 = 0.5 mg/kg i.p. and 1.9 mg/kg p.o., respectively). Methamphetamine (10 mg/kg i.p.)-induced stereotyped behavior in mice was dose-dependently antagonized by NRA0045, whereas NRA0045 did not exceed 50% inhibition even at the highest dose given (30 mg/kg i.p.). Catalepsy was dose-dependently and significantly induced by NRA0045 in rats, whereas NRA0045 did not exceed 50% induction even at the highest dose given (30 mg/kg i.p.). Thus NRA0045 blocks behaviors associated with activation of the mesolimbic/mesocortical dopaminergic neurons more selectively than behaviors associated with nigrostriatal dopaminergic neurons. In rats, tryptamine-induced clonic seizure, a 5-HT2 receptor-mediated behavior, was also dose-dependently inhibited by NRA0045 (ED50 = 1.7 mg/kg i.p.). Norepinephrine-induced lethality is regarded as being induced through the alpha-1 adrenoceptor. NRA0045 dose-dependently antagonized norepinephrine-induced lethality in rats (ED50 = 0.2 mg/kg i.p.). Thus NRA0045 may have a unique antipsychotic activity with regard to dopamine D4 and 5-HT2A receptors and alpha-1 adrenoceptor antagonistic activities, without producing the extrapyramidal side effects.

Adrenergic alpha-1 Receptor Antagonists↗

Effects of newly synthesized amino acids containing thiazole residues on electrically evoked smooth muscle contractions.

New amino acids containing thiazole residues have been synthesized and in vitro experiments were performed to study their action on neurotransmission in target tissues with adrenergic and cholinergic neurotransmission. Acetaminothiazoles, structurally related to the novel class, are known to act as H1 agonists, therefore, the effects of the newly synthesized Ala- and Pro-thiazole derivatives on smooth muscle contractile activity were compared to those of histamine (HA). The experiments were carried out on electrically stimulated prostatic part of rat and rabbit vasa deferentia and proximal guinea pig ileum. HA had biphasic effect on electrically evoked neurogenic contractions of guinea pig ileum, Pro(Thz) had a stimulating effect, while Ala(Thz) had no effect. The histamine H1-receptor antagonist diphenhydramine inhibited the Pro(Thz)-induced spontaneous contractile activity in the longitudinal layer of guinea pig ileum. HA had a biphasic effect on electrically induced neurogenic contractions of rat and rabbit vasa deferentia while Pro(Thz) and Ala(Thz) inhibited the ES-contractions. The present results show that the newly synthesized compounds might affect the electrically evoked smooth muscle contractions. Some similarity in the effects of HA and of the new substances was observed.

Amino Acids↗

Viability testing of homograft valves using methyl thiazol tetrazolium assay.

Viability status before and after treatment with antibiotics was investigated in a total of 104 homograft valves using MTT (3-[4, 5-dimethyl thiazol-2-y1]-2, 5-diphenyl tetrazolium bromide). The valves with warm ischaemic time above 11 hours, were found to be non-viable. Increase in storage time directly decreases cell viability. Methyl thiazol tetrazolium (MTT) assay can be used as a reliable, simple, rapid and economic method for assessing the viability status based on mitochondrial respiration even for homograft valves. Basal media with and without nutrients i.e., DMEM and Hanks BSS showed no difference in viability of the cells.

Adolescent↗

Effects on rat testes of the thiosemicarbazone derivative Schiff base (4-(1-phenylmethylcyclobutane-3-yl)-2-(2-hydroxybenzylidenehydrazino)thiazole) and its cadmium(II) complex.

The aim of this study was to investigate structural and biochemical changes in testes of rats treated with the thiosemicarbazone derivative thiazole ring Schiff base, (4-(1-phenyl-methylcyclobutane-3-yl)-2-(2-hydroxybenzylidene-hydrazino) thiazole (L), and its Cd(II) complex (CdL(2)). The animals were divided into three groups. Group I was designated as control. The rats in groups II and III were injected subcutaneously with L or CdL(2) respectively at 150-mg kg(-1) doses at 3-day intervals for 15 days. At the end of the study, blood samples were collected for biochemical analysis, and testes were removed for histological examinations. Serum levels of vitamin A, E and MDA of the L-injected group were similar to the control group. While CdL(2) treatment decreased serum vitamin A and E levels, it increased the MDA level compared to other groups. Histologically, the testes structures of L-treated animals were similar to the control. Spermatogenic cells in seminiferous tubules of CdL(2)-treated animals displayed necrosis. Nuclei of spermatogonia and primary spermatocytes were pyknotic and heterochromatic. Homogenous pink particles were present in place of the spermatids. The interstitial areas were oedematous and intertubular vessels were plugged. In conclusion, the present results indicate that L does not cause biochemical and morphological alterations, but its Cd(II) complex has degenerative effects in normal rat testes.

Animals↗

Exploring base-pair-specific optical properties of the DNA stain thiazole orange.

Double-stranded DNA offers multiple binding sites to DNA stains. Measurements of noncovalently bound dye-nucleic acid complexes are, necessarily, measurements of an ensemble of chromophores. Thus, it is difficult to assign fluorescence properties to base-pair-specific binding modes of cyanine dyes or, vice versa, to obtain information about the local environment of cyanines in nucleic acids by using optical spectroscopy. The feasibility to stain DNA and simultaneously probe local perturbations by optical spectroscopy would be a valuable asset to nucleic acid research. So-called FIT probes (forced intercalation probes) were used to pinpoint the location of the DNA stain thiazole orange (TO) in PNADNA duplexes. A detailed analysis of the base-pair dependence of optical properties is provided and enforced binding of TO is compared with "classical" binding of free TO-PRO1. UV-visible absorbance, circular dichroism (CD) and fluorescence spectroscopy, and melting-curve analyses confirmed site-specific TO intercalation. Thiazole orange exhibited base-specific responses that are not observed in noncovalent dye-nucleic acid complexes, such as an extraordinary dependence of the TO extinction coefficient (+/-60 % variation of the averaged epsilon(max) of 57,000 M(-1) cm(-1)) on nearest-neighbor base pairs. TO signals hybridization, as shown by increases in the steady-state fluorescence emission. Studies of TO fluorescence lifetimes in FIT-PNA and in DNADNA and PNADNA complexes highlighted four different fluorescence-decay processes that may be closed or opened in response to matched or single-mismatched hybridization. A very fast decay process (0.04-0.07 ns) and a slow decay process (2.33-3.95 ns) provide reliable monitors of hybridization, and the opening of a fast decay channel (0.22-0.48 ns) that resulted in an attenuation of the fluorescence emission is observed upon the formation of mismatched base pairs.

Base Pairing↗

Synthesis and pharmacological properties of some 4-amino-5-substituted thiazole-2(3H)-thiones and thiazolo(4,5-d)pyrimidin-7(6H)-one-2(3H)-thiones.

4-Amino-5-substituted thiazole-2(3H)-thiones and thiazolo(4,5-d)-pyrimidin-7(6H)-one-2(3H)-thiones have been synthesized and screened for antimicrobial and pharmacological activities. Significant analgesic, antiinflammatory, anticonvulsant and antimicrobial properties have been found in some of the compounds synthesized. Analgesic and antiinflammatory activities are reported for the first time in thiazole-2(3H)-thiones.

Analgesics↗

1,3'-Diethyl-4,2'-quinolylthiacyanine iodide as a "thiazole orange" analogue for nucleic acid staining.

Flow cytometric evaluation of reticulocytes has become a valuable and more precise alternative for the microscopically determined reticulocyte count. Until now, the most promising results are obtained with the "thiazole orange" (TO) nucleic acid dye. We report on the use of a "thiazole orange" analogue, 1,3'-diethyl-4,2'-quinolylthiacyanine iodide (DEQTC), which gives comparable results and is commercially available at low cost.

Benzothiazoles↗

Synthesis, antibacterial, antifungal and anti-HIV activities of Schiff and Mannich bases derived from isatin derivatives and N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide.

Isatin, its 5-chloro and 5-bromo derivatives have been reacted with N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting them with formaldehyde and three secondary amines. Their chemical structures have been confirmed by means of IR, 1H-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by agar dilution method against 28 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (IIIB) in MT-4 cells. Among the compounds tested 1-[N,N-dimethylaminomethyl]-5-bromo isatin-3-{1'-[4"-(p-chlorophenyl) thiazol-2"-yl] thio semicarbazone} 10 showed the most favourable antimicrobial activity.

Anti-Bacterial Agents↗

From thiourea to bicyclic structures: an original route to imidazo[2,1-b]thiazoles, 5H-thiazolo[3,2-a]pyrimidines, 7H-imidazo[2,1-b][1,3]thiazines, and 2H,6H-pyrimido[2,1-b][1,3]thiazines.

We report an example of an efficient regioselective synthesis of biheterocyclic compounds using thiourea as starting material. In fact, N,N'-bis(dimethylaminomethylene)thiourea (1), easily prepared by double condensation of N,N-dimethylformamide dimethyl acetal with thiourea, can be reacted with haloketones or acrylic dienophiles to give thiazolic (2) and thiazinic (3) diazadienes, respectively, themselves undergoing cyclization reactions to yield imidazo[2,1-b]thiazoles, 5H-thiazolo[3,2-a]pyrimidines, 7H-imidazo[2,1-b][1,3]thiazines, and 2H,6H-pyrimido[2,1-b][1,3]thiazines without any regioisomeric ambiguity. This straightforward route represents an original and unambiguously regioselective pathway to these valuable heterocycles.

Journal Article↗

Reactivity of 2-deoxy-2-iodoglycosyl isothiocyanates with O-, S-, and N-nucleophiles. Synthesis of glycopyranoso-fused thiazoles.

The reactivity of 2-deoxy-2-iodoglycosyl isothiocyanates toward O- and S-nucleophiles gives an easy access to 2-deoxy-2-iodoglycopyranosyl thiocarbamates and dithiocarbamates. Internal nucleophilic displacement of the iodine by the sulfur atom in these compounds allows the preparation of glycopyranoso[1,2-d]-1,3-thiazoles and glycopyranoso[1,2-d]-1,3-thiazolidin-2-one or -2-thione. Reaction with amines or polyamines as N-nucleophiles led directly to 2-aminoglycopyranoso[1,2-d]-1,3-thiazoles without isolation of the intermediate thioureas. Methyl 2-deoxy-2-iodoglycopyranosyl thiocarbamates also allow the synthesis of 2-deoxyglycopyranosyl thiocarbamates or 2-deoxy-2-iodoglycopyranosyl carbamates.

Journal Article↗

Stereochemical control factors in the Hantzsch thiazole synthesis: a Hammett substitution correlation analysis.

[reaction--see text] It is possible to correlate the distribution of stereochemical products produced during a Hantzsch thiazole synthesis according to the Hammett free-energy equation. This analysis confirms the presumed control of the rate of epimerization during thiazole formation due to stabilization of a cationic transition state intermediate during dehydration of the thiazoline ring system. In the chemical system under study, the stereochemical outcome of the reaction also appears to occur according to a kinetically controlled protonation of a thiazoline tautomer.

Journal Article↗

2,3-Dihydro-3-methyl-2-nitrimino-1,3-thiazole.

The title compound ¿alternatively, 3-methyl-2-[oxido(oxo)hydrazono]-2,3-dihydro-1,3-thiazole¿, C(4)H(5)N(3)O(2)S, was obtained by methylation of N-(2-thiazolyl)nitramine. The molecule lies on a mirror plane and the thiazole ring is planar, regular in shape and aromatic. The S atom participates in the aromatic sextet via an electron pair on the 3p(z) orbital. In the crystal, the molecules are arranged in parallel layers, bound to each other by weak C-H.O and C-H.N hydrogen bonds and by S.O dipolar interactions, with an interlayer separation of 3.23 A.

Journal Article↗

Dichloro(2,2'-diamino-4,4'-bi-1,3-thiazole-N3,N3')copper(II).

The title complex, [CuCl(2)(C(6)H(6)N(4)S(2))], has a flattened tetrahedral coordination. The Cu(II) atom is located on a twofold rotation axis and is coordinated by two N atoms from a chelating 2,2'-diamino-4,4'-bi-1,3-thiazole ligand and by two Cl atoms. Intramolecular hydrogen bonding exists between the amino groups of the 2,2'-diamino-4,4'-bi-1,3-thiazole ligand and the Cl atoms. The intermolecular separation of 3.425 (1) A between parallel bithiazole rings suggests there is a pi-pi interaction between them.

Journal Article↗