Selenocyanate Research Articles

Organic Selenocyanates: Synthesis, Characterization and Uses in Chemistry and Biology

In the first part, the preparation of these compounds is reported. Organic selenocyanates have been synthesized by reaction of substrates with potassium selenocyanate, selenium diselenocyanate, diselenocyanate or selenium dicyanate. The reactions of selenenyl halides with cyanide ions or selenolates with cyanogen bromide are also efficient. In the second part, the physicochemical properties of organic selenocyanates are described. Infrared, NMR, Photoelectron and Microwave spectra are successively commented for the simplest alkyl, aryl and functionalized derivatives, viz. methyl-, phenyl-, vinyl-, ethynyl-, allyl-, propargyl-, allenyl and cyclopropylselenocyanates. The chemical reactions involving organic selenocyanates are then reported showing the diversity of applications of these compounds in the preparation of other selenium derivatives. In the last part, the recent applications of some derivatives for their antistress, antiradiation, antioxidative, antimutagenic, anticarcinogen and chemopreventive properties are summarized.

Potassium selenocyanate as an efficient selenium source in C–Se cross-coupling catalyzed by copper iodide in water

An efficient and conceptually new protocol for C–Se cross coupling of potassium selenocyanate with aryl halides via copper-catalyzed cascade reaction has been developed in water. Utilizing this protocol, a variety of aryl and heteroaryl halides were reacted with potassium selenocyanate to afford the corresponding diaryl selenides in moderate to good yields.

Nano Copper Oxide Catalyzed Synthesis of Symmetrical Diaryl Selenides via Cascade Reaction of KSeCN with Aryl Halides

An unprecedented transfer of selenium ion from potassium selenocyanate was observed in C-Se cross-coupling reaction catalyzed by copper oxide nanoparticles under ligand-free conditions. Utilizing this protocol wide range of symmetrical diaryl selenides were obtained in excellent yields. Nano-CuO is recyclable up to four cycles without loss of catalytic activity.

Synthesis of arylselenide ethers by photoinduced reactions of selenobenzamide, selenourea and selenocyanate anions with aryl halides

Selenobenzamide (−SeCNH(Ph), 1), selenourea (−SeCNH(NH2), 2) and selenocyanate (−SeCN, 3) anions afford areneselenolate ions (ArSe−) under photostimulation in the presence of tert-butoxide or 2-naphthoxide ions as electron donors (entrainment conditions) in DMSO. In a ‘one-pot’ procedure, ArSe− anions can be trapped by a subsequent aliphatic nucleophilic substitution giving aryl methyl selenides in good to excellent yields (67–100%). This simple approach is compatible with electron-donating and electron-withdrawing substituents, such as nitro and carbonyl groups.

Poly[diaquatetra-μ-selenocyanato-cadmium(II)dipotassium(I)

In the title compound, [CdK2(NCSe)4(H2O)2]n, the cadmium(II) cation is situated on a twofold rotation axis and is coordinated in a slightly distorted tetra­hedral geometry by two symmetry-related μ-1,1,1,3 and two-symmetry related μ-1,1,3,3 bridging seleno­cyanate anions, all of which are Se bonded. These bridging seleno­cyanate anions are further coordinated to two symmetry-related potassium ions. Each of the potassium ions is coordinated by one terminally bonded water mol­ecule and six seleno­cyanate anions, two of which are crystallographically independent. The asymmetric unit consists of one cadmium and one potassium cation, two bridging seleno­cyanate anions and one water mol­ecule. The polymeric subunits are further connected via the seleno­cyanate anions into a three-dimensional coordination network. In this coordination network, intramolecular hydrogen bonds between neighbouring water molecules can be found.

Reactions with Hydrazonoyl Halides 63: Synthesis and Anticancer Activity of Some New 1,3,4-Thiadiazoles, 1,3,4-Selenadiazoles, and 1,2,4-Triazolo[4,3-a]pyrimidines

2,3-Dihydro-1,3,4-thiadiazoles, 2,3-dihydro-1,3,4-selenadiazoles, and triazolino[4,3-a]pyrimidines containing benzoxazole or benzothiazole moieties were prepared from the reaction of each of ethyl 3-aza-3-(benzoxazol-2-ylamino)-2-chloroprop-2-enoate and ethyl 3-aza-3-(benzothiazolo-2-ylamino)-2-chloroprop-2-enoate with each of potassium thiocyanate, potassium selenocyanate, alkyl carbodithioate, and pyrmidine-2-thione derivatives. All the newly synthesized compounds were confirmed by elemental analysis, spectral data, and alternative route synthesis whenever possible. Some of the newly synthesized compounds were screened toward certain cancer tumors. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Mode-specific intermolecular vibrational energy transfer. II. Deuterated water and potassium selenocyanate mixture

Vibrational energy transfer from the first excited state (2635 cm(-1)) of the O-D stretch of deuterated water (D(2)O) to the 0-1 transition (2075 cm(-1)) of the CN stretch of potassium selenocyanate (KSeCN) in their 2.5:1 liquid mixture was observed with a multiple-mode two dimensional infrared spectroscopic technique. Despite the big energy mismatch (560 cm(-1)) between the two modes, the transfer is still very efficient with a time constant of 20 ps. The efficient energy transfer is probably because of the large excitation coupling between the two modes. The coupling is experimentally determined to be 176 cm(-1). An approximate analytical equation derived from the Landau-Teller formula is applied to calculate the energy transfer rate with all parameters experimentally determined. The calculation results are qualitatively consistent with the experimental data.

Synthesis of Unnatural Selenocystines and β-Aminodiselenides via Regioselective Ring-Opening of Sulfamidates Using a Sequential, One-Pot, Multistep Strategy

A variety of N-alkyl-beta-aminodiselenides have been synthesized in high yield from sulfamidates under mild reaction conditions using potassium selenocyanate and benzyltriethylammonium tetrathiomolybdate ([BnNEt(3)](2)MoS(4)) in a sequential, one-pot, multistep reaction. The tolerance of multifarious protecting groups under the reaction conditions is discussed. The methodology was successfully extended to the synthesis of selenocystine, 3,3'-dialkylselenocystine, and 3,3'-diphenylisoselenocystine and their direct incorporation into peptides.

Synthesis and biological evaluation of novel spiro 6-methoxytetralin-1,3′-pyrrolidine based organoselenocyanates against cadmium-induced oxidative and hepatic damage in mice

A series of novel organoselenocyanate compounds ( 6a– d) having spiro[tetralin-1,3′-pyrrolidine] moiety were synthesized. The compounds were evaluated for their inhibitory activity against cadmium- (Cd) induced toxicity in Swiss Albino mice. All the compounds ( 6a– d) inhibited the level of lipid peroxidation (LPO) and upregulated the activity of glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) levels in treatment group in comparison to the untreated Cd control group. Serum transaminase activities, e.g., alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also significantly lowered in the compound-treated mice. Elongation of the alkyl chain length bearing the selenocyanate (SeCN) active group enhanced the potency of the compounds, 6d being the most active one ( 6d > 6c > 6b > 6a).

Synthesis of 8-Hydroselenoquinoline and Its Derivatives

The methods of synthesis 8-hydroselenoquinoline and its alkyl-, alkyloxy- and phenyl- derivatives have been discussed in the present work. The applicability of potassium selenocyanate and selenourea as the selenium-introducing reagent has been studied. The best results are obtained by the use of selenourea as the selenium-introducing agent. Using this reagent it seems to be possible to obtain some derivatives of 8-hydroselenoquinoline that cannot be synthesized by using potassium selenocyanate as selenium-introducing agent. The corresponding 8,8diquinolyldiselenide and methylselenoquinolines synthesized also. The obtained substances characterized by UV-spectra.

Short and General Procedure for Synthesizing Cis-1,2-Fused 1,3-Oxathiolan-, 1,3-Oxaselenolan-, and 1,3-Oxazolidin-2-imine Carbohydrate Derivatives

Novel cis-1,2-fused 1,3-oxathiolan-, 1,3-oxaselenolan-, and 1,3-oxazolidin-2-imine carbohydrate derivatives have been prepared by treatment of the corresponding 1,2-anhydrosugars with potassium thiocyanate, potassium selenocyanate, and sodium cyanamide, respectively. The procedure is compatible with several protecting groups such as acyl, benzyl, and silyl and also with sugars of different configurations.

Biological interactions of selenocyanate: Bioprocessing, detection and toxicity

The selenocyanate anion, SeCN−, has been reported in wastewater from refineries whose petroleum comes from Se‐rich marine shales. A metalloid‐resistant bacterium was exposed to aqueous solutions of SeCN− to examine the relative toxicity of SeCN−, and the results were compared with the toxicity of selenate and selenite and another G16 metalloid oxyanion, tellurite. We also determined the volatile organo‐selenium species produced by bacterial cultures amended with selenocyanate anion, and we investigated a solid phase preconcentration technique for collecting SeCN− from aqueous samples with different ionic strengths and subsequent detection using capillary electrophoresis. The relative toxicity of SeCN− is comparable to that of selenate and selenite using the metalloid‐resistant bacterium LHVE as the test organism. Tellurite was more toxic at all concentrations examined than all three selenium‐containing anions, SeO4 2−, SeO3 2−, SeCN−. Live cultures of LHVE amended with 1 mM NaSeCN produced volatile organo‐sulphides and organo‐selenides that could be collected in headspace using a solid phase microextraction fibre. The bioprocessing, i.e. the reduction and methylation of SeCN−, is similar to that of selenate and selenite by other metalloid‐resistant bacteria. An aqueous 1.0 mM solution of SeCN− could be captured from solution on solid‐phase extraction (SPE) cartridges using an aminopropyl‐based stationary phase. Selenocyanate anions, slowly pumped into a wetted SPE cartridge, were trapped on the cartridge’s solid phase and were subsequently eluted, thereby providing an increase in concentration above that of the original SeCN−‐containing solution. Preconcentration factors of 3.9 were achieved using a mixed sodium hydroxide/methanol elution solvent and by adding NaCl to aqueous SeCN− before loading on the SPE cartridge.

Effect of selenium oxidation state on cadmium translocation in chamomile plants

AbstractSyntheses and spectral characteristics of cadmium(II) compounds (CdSeO4, CdSeO3, and Cd(NCSe)2(nia)2) containing selenium in oxidation states (VI), (IV), and (-II) are described. In Cd(NCSe)2(nia)2, nicotinamide (nia) and selenocyanate anions are bonded to Cd atom as N-donor monodentate ligands. Nicotinamide is coordinated through the ring nitrogen atom. The effects of these selenium compounds as well as Cd(NCS)2(nia)2 on the growth and Cd accumulation in roots and shoots of hydroponically cultivated chamomile plants (cultivar Lutea) were studied. In the applied concentration range (12–60 µmol dm−3) Cd(NCS)2(nia)2 affected neither the length nor the dry mass of roots and shoots. Other compounds applied at 24 µmol dm−3 and 60 µmol dm−3 significantly reduced dry mass of roots and shoots. Selenium oxidation state in the cadmium compounds affected Cd accumulation in plant organs as well as Cd translocation within the plants, which was reflected in the values of bioaccumulation (BAF) and translocation factors (S/R). Cd amount accumulated by shoots was lower than that in the roots. The highest BAF values determined for Cd accumulation in shoots were obtained with CdSeO4. Substitution of S with Se in the Cd(NCX)2(nia)2 (X = Se or S) caused an increase of Cd translocation into the shoots.

‘Rings and rectangles’ mediated through weak interactions in ionic solids: Synthesis and packing analysis of [Co(NH3)6]Cl2SeCN and [Co(NH3)6]3Cl4(N3)5 in the crystalline state

The reaction of hexaamminecobalt(III) chloride with sodium azide and potassium selenocyanate (1 ∶ 3 molar ratio) in hot aqueous medium leads to formation of reddish-orange crystals of composition [Co(NH3)6]Cl2SeCN (1) and [Co(NH3)6]3Cl4(N3)5 (2), respectively. Single crystal X-ray structural analysis of 1 and 2 reveals the supramolecular hydrogen bonding network between ionic groups (i.e. SeCN− or N3− and Cl−) and the hydrogen atom of the coordinated NH3 molecules leading to the formation of ‘rings’ (in 1) or ‘rectangles’ (in 2) of ions in their respective lattices. Though linear, small topological difference of size and shape between the selenocyanate and azide anions manifests in different packing modes in these compounds. The formation of a ‘small’ rectangle inside a ‘large’ rectangle of ions makes the packing of 2 remarkably unique.

Direct Synthesis of Novel 2‐Imino‐1,3‐selenazolidine Derivatives from O‐Methanesulfonyl β‐Amino Alcohol Hydrochlorides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Quinoline‐8‐selenol, Its Complex Compounds with Metals and Their Cytotoxic Activity.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reactions with Hydrazonoyl Halides 421: Synthesis of Some New 2,3-Dihydro-1,3,4thiadiazoles, 2,3-Dihydro-1,3,4-selenadiazoles and Triazolino[[4], [3]]pyrimidines

2,3-Dihydro-1,3,4-thiadiazoles, 2,3-dihydro-1,3,4-selenadiazoles, unsymmetrical azines and triazolino[[4], [3]]pyrimidines were prepared from reaction of (2Z)-3-aza-2-bromo-1-naphto[[1], [2]]furan-2-yl-3-(phenylamino)prop-2-en-1-one (6) with each of potassium thiocyanate, potassium selenocyanate, alkyl carbodithioate, ethyl 6-methyl-2-methylthio-4-substituted 3,4-dihydropyrimidine-5-carboxylate or (ethyl 4-methyl-6-substituted 2-thione-1,3,6-trihydropyrimidine-5-carboxylate). All compounds were elucidated on the basis of elemental analysis, spectral data, and alternative synthesis method whenever possible.

Direct synthesis of novel 2-imino-1,3-selenazolidine derivatives from O-methanesulfonyl β-amino alcohol hydrochlorides

Recently, we have reported that 4,5-dialkylsubstituted 2-imino-1,3-azolidine derivatives ( 1 ) strongly inhibit inducible nitric oxide synthase (iNOS). To our knowledge, only few methods have been reported for the synthesis of 4,5-dialkylsubstituted 2-imino-1,3-selenazolidine derivatives ( 2 ), which are the selenium analogue of 1 . Herein, we report the direct synthesis of 2 from the corresponding O-methanesulfonyl β-amino alcohol hydrochlorides using potassium selenocyanate and evaluation for the inhibitory activity against iNOS of the newly synthesized selenazolidine derivatives.

Reactions of hydrazonoyl halides 44 [1]: synthesis of some new 1,3,4-thiadiazolines, 1,3,4-selenadiazolines and triazolino[4,3- a ]pyrimidines

1,3,4-Thiadiazolines, 1,3,4-selenadiazolines and triazolino[4,3-a]pyrimidines have been synthesized from 3-aza-[2,4-dimethyl(1,3-thiazol-5-yl)-2-bromo-3-substituted-amino]prop-2-en-1-ones with potassium thiocyanate, potassium selenocyanate, alkyl carbodithioates and 6-methyl-2-methylthio-4-substituted 3,4-dihydropyrimidine-5-carboxylates. Structures of the newly synthesized compounds have been established by elemental analysis, spectral data and alternative synthesis whenever possible. Some of products have been tested towards bacteria.

Synthesis of Quinoline-8-selenol, Its Complex Compounds with Metals and Their Cytotoxic Activity

We have developed a novel method for synthesis of quinoline-8-selenol using selenourea instead of the previously used potassium selenocyanate. We have synthesized a series of metal quinoline-8-selenolates. We have studied the cytotoxic activity of the synthesized compounds against HT-1080, MG-22A, B16, Neuro 2A tumor cells. Mercury quinoline-8-selenolate is distinguished by high cytotoxicity for the three cell lines; the cadmium complex is most effective against B16 melanoma cells.