Presence Of Stannic Chloride Research Articles

Synthesis and biodistribution in mice of 99mTcN–DBODC–DMSEt

AbstractNitrido technetium(V)‐mixed ligand complex of 99mTcN–DBODC–DMSEt [DMSEt: Monoethyl ester of (meso) 2,3‐dimercaptosuccinic acid, DBODC: bis(2‐ethoxyethyl)carbamodithioate] has been prepared in a two‐step procedure by first reaction of 99mTcO with succinic dihydrazede in the presence of stannous chloride as a reducing agent and propylenediamine tetraacetic acid as a complexant, followed by the addition of DMSEt and DBODC. The complex was stable over 6 h at room temperature. The partition coefficient indicated that it was a hydrophilic complex. Biodistribution in mice demonstrated that the complex accumulated mainly in liver, lungs and kidneys. Copyright © 2009 John Wiley & Sons, Ltd.

Synthesis of a bis(2,3-dimethylcyclohexyl-dithiocarbamato)-nitrido 99mTc complex: A potential tracer for myocardial imaging

The 99mTcN(DMCHDTC) 2 complex, where DMCHDTC is 2,3-dimethylcyclohexyl dithiocarbamato, has been synthesized through a ligand-exchange reaction. The two-step procedure involved the initial reaction of 99mTcO 4 − with succinic dihydrazide in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid as complexant, followed by the addition of 2,3-dimethylcyclohexyl dithiocarbamate. The radiochemical purity of the complex was over 90%, as measured by thin layer chromatography, without any notable decomposition at room temperature over a period of 6 h. The partition coefficient and electrophoresis results indicated that this complex was lipophilic and neutral. Biodistribution in mice showed that the complex accumulated in the heart with high uptake and good retention, the heart uptakes being 12.82, 11.37 and 10.64%ID/g at 5, 30 and 60 min post-injection, respectively. The heart/lung, heart/liver and heart/blood ratios of the complex were 1.06, 0.25 and 8.06 at 60 min post-injection, suggesting it has potential for use as a myocardial imaging agent.

Selenophilicity of Copper in Selenium-Carbon Bond Formation from Selenous Acid Using Cu(II)/Sn(II) Reagent

A selenium transfer reaction from selenous acid to benzyl and alkyl halides is initiated in the presence of stannous chloride and a catalytic amount of cupric chloride resulting in the formation of the corresponding diorganoselenides and/or diorganodiselenides as the major products as indicated by 1 H, 13 C, 77 Se NMR, and MS. The reaction is characterized by a dual-metal effect at the selenium activation and transfer step. Thus, initial reaction of stannous chloride, cupric chloride, and selenous acid gives rise to α-Cu 2 Se. Selenium transfer from the latter to the organic halide takes place with additional assistance of stannous chloride.

Synthesis of a bis-(N-butyl-dithiocarbamato)-nitrido 99mTc complex: A potential new brain imaging agent

The bis(N-butyl dithiocarbamato) nitrido 99mTc complex [99mTcN(BDTC)2] (BDTC: N-butyl dithiocarbamato) has been synthesized through a ligand-exchange reaction. The two-step procedure consisted of an initial reaction of 99mTcO4 − with succinic dihydrazide (SDH) in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid (PDTA) as complexing agent, and subsequent addition of sodium salt of N-butyl dithiocarbamate. The radiochemical purity of the complex was over 90%, as measured by thin layer chromatography. No decomposition of the complex at room temperature was observed over a period of 6 hours. Its partition coefficient indicated that it was a lipophilic complex. The electrophoresis results showed the complex was neutral. Biodistribution in mice showed that the complex accumulated in the brain with high uptake. The brain/blood ratio was 1.58, 1.67 and 1.20 at 5, 30 and 60-minute post-injection, respectively, suggesting this compound would be a potential cerebral imaging agent.

Determination of dithiocarbamate fungicide propineb and its main metabolite propylenethiourea in airborne samples

A simple, rapid and sensitive GC–MS method for the determination of dithiocarbamate fungicide propineb [polymeric zinc propylenebis (dithiocarbamate)] and an improved HPLC procedure for the simultaneous determination of its main metabolite, propylenethiourea, and ethylenethiourea, the main metabolite of all ethylenedithiocarbamates, in airborne samples are described. The method for the analysis of propineb involves the evolution of carbon disulfide (CS 2), under acidic conditions in the presence of stannous chloride, extraction of the generated CS 2 into a layer of isooctane which is then analyzed for CS 2 content by GC–MS in SIM mode. Under the optimum conditions, the retention time of CS 2 was 1.89 min and the total time of chromatographic analysis was 5 min. Recoveries from spiking glass microfibre filters (GF/A) and silica gel filters were 86 ± 7 ( n = 9) and 89 ± 4 ( n = 9), respectively. The limit of detection is 0.7 ng per filter, which is equivalent to about 0.8–1.0 ng m −3 in air. In parallel, an HPLC method with ultraviolet detection is presented for the simultaneous analysis of the metabolites. Separation of the two metabolites was attained in less than 5 min. Recoveries from spiking GF/A and silica gel filters for ethylenethiourea were 100 ± 1 ( n = 3) and 98 ± 2 ( n = 3), respectively, while for propylenethiourea were 102 ± 1 ( n = 3) and 98 ± 1 ( n = 3), respectively. The detection limits are about 36–43 and 40–49 ng m −3 in air for ethylenethiourea and propylenethiourea, respectively. All the analytes spiked in the filters are proven to be stable for more than one month, at −4 °C.

A One‐Pot Synthesis of 1‐α‐ and 1‐β‐D‐Arabinofuranosyl‐2‐nitroimidazoles: Synthons to the Markers of Tumor Hypoxia.

1-α-and 1-β-D-Arabinofuranosyl-2-nitroimidazole (α-AZA and β-AZA) are synthons for a number of potential markers of tissue hypoxia. A one pot synthesis in which 2-nitroimidazole is coupled with a mixture of α-and β-1-O-acetyl-2,3,5-tri-O-benzoyl-D-arabinofuranose in the presence of stannic chloride, followed by deprotection using ammonia/methanol, is described. Previously reported conditions for coupling 2-nitroimidazole to 1-α-bromoarabinofuranose protected by base-hydrolyzable groups afforded α-AZA almost exclusively.

A One-Pot Synthesis of 1-α- And 1-β-D-Arabinofuranosyl-2-Nitroimidazoles: Synthons to the Markers of Tumor Hypoxia

1-α-and 1-β-D-Arabinofuranosyl-2-nitroimidazole (α-AZA and β-AZA) are synthons for a number of potential markers of tissue hypoxia. A one pot synthesis in which 2-nitroimidazole is coupled with a mixture of α-and β-1-O-acetyl-2,3,5-tri-O-benzoyl-D-arabinofuranose in the presence of stannic chloride, followed by deprotection using ammonia/methanol, is described. Previously reported conditions for coupling 2-nitroimidazole to 1-α-bromoarabinofuranose protected by base-hydrolyzable groups afforded α-AZA almost exclusively.

Synthesis and characterization of functional l-lactic acid/citric acid oligomer

Oligomers of l-lactic acid and citric acid (PLCA) were synthesized by reacting lactic acid with citric acid in the presence of stannous chloride. The chemical compositions of these multicarboxylated oligomers were verified by FT-IR and 1H-NMR spectroscopy. The thermal characteristics of the oligomers, such as glass transition temperature T g, melting temperature T m and melting enthalpy, were confirmed by DSC. The crystallinity of the oligomers were determined by DSC and WXRD. Meanwhile, the acid–base surface characteristics of PLCA have been determined by contact angle. The results implicated that these oligomers may be used to entrap the cospecies on PLLA surface in tissue engineering.

Synthesis and biodistribution of99mTcN(PDTC)2as a potential brain imaging agent

The preparation of the bis(N-propyl dithiocarbamato) nitrido technetium-99m complex 99mTcN(PDTC)2 (PDTC: N-propyl dithiocarbamato) was carried out as a freeze-dried formulation, through a simple procedure involving the initial of 99mTcO4- with succinic dihydrazide in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid (PDTA) as complexant, followed by the addition of the ligand sodium salt of N-propyl dithiocarbamate to afford the final product. The radiochemical purity of the complex was over 90%, as measured by thin layer chromatography. No decomposition of the complex at room temperature was observed over a period of 12 hours. Its partition coefficient indicated that it was a good lipophilic complex. Biodistribution in mice showed that the complex accumulated in the brain with high uptake. The brain uptake (ID%/g) was 5.07 and the brain/blood ratio 1.34 at 5-minute post-injection. This suggested a potential usefulness of the complex as a brain perfusion imaging agent.

Technetium-99m labeling of tityustoxin and venom from the scorpion Tityus serrulatus

The tityustoxin, the most toxic fraction from scorpion Tityus serrulatus venom, has been used as a tool in several neurochemical and neuropharmacological studies. Biological activities of labeled and unlabeled tityustoxin and venom were compared. The samples were labeled in the presence of stannous chloride and sodium borohydride with a yield of 60–70% for the venom and 75–85% for tityustoxin and then chromatographed in Sephadex G-10. Biological activities of tityustoxin and venom were preserved after labeling.

Diastereoselective addition of gamma-substituted allylic nucleophiles to ketones: highly stereoselective synthesis of tertiary homoallylic alcohols using an allylic tributylstannane/stannous chloride system.

The diastereoselective addition of gamma-substituted allylic nucleophiles to ketones has been accomplished to give tertiary homoallylic alcohols. The reaction of tributylcinnamyltin 1a with simple ketones 2 in the presence of stannous chloride (SnCl(2)) gave the tertiary homoallylic alcohols 3, which include the anti form (based on Ph and OH), with high diastereoselectivity. In the reaction course, transmetalation of tributylcinnamyltin 1a with SnCl(2) proceeds to form an active nucleophile which is tentatively considered to be a cinnamyltin(II) species. A cyclic transition state A is favorable because the chlorinated tin(II) center is highly capable of accepting ligands. The other diastereomers (syn form) 4 were obtained in the reaction of tributylcinnamyltin 1a with ketones 2 by the use of BF(3) x OEt(2) instead of SnCl(2). This reaction proceeds through an acyclic transition state in which BF(3) acts as a Lewis acid for activation of ketones. When 3-tributylstannylcyclohexene 1b or 3-tributylstannylcyclopentene 1c was used with SnCl(2), high diastereoselective formation of the corresponding homoallylic alcohols 6 which have the syn form (based on ring chain and OH) was observed. The selectivity was also explained by the cyclic transition state B. When tributylcrotyltin 1d or 1e was used, the stereochemistry of the products depends on the additives (SnCl(2) or BF(3) x OEt(2)), substituents of ketones, and reaction temperature. It is interesting that those additives compensate for each other in terms of diastereoselective alkylation. The alkylation of alpha-alkoxy, aryloxy, or hydroxyketones 16 was achieved in extremely high selectivity using an allylic tributyltin 1a-c/SnCl(2) system. The chelation by carbonyl and beta-oxygens provides a rigid transition state (E or F) for selective reactions. It is noted that the hydroxyketone can be used without protection in this reaction system. The relative stereochemistry of the produced tertiary homoallylic alcohols was determined on the basis of X-ray analyses.

Synthesis and biodistribution of 99mTcN(CHIPDTC)2 as a potential myocardial perfusion imaging agent

The bis(N-cyclohexyl, N-isopropyl dithiocarbamato) nitrido technetium-99m complex [99mTcN(CHIPDTC)2] (CHIPDTC: N-cyclohexyl, N-isopropyl dithiocarbamato) has been synthesized through a ligand-exchange reaction. The two-step procedure involved the initial reaction of 99mTcO4- with succinic dihydrazide (SDH) in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid (PDTA) as complexant, followed by the addition of the sodium salt of N-cyclohexyl, N-isopropyl dithiocarbamate. The radiochemical purity (RCP) of the complex was 96±2% as measured by thin layer chromatography (TLC). No decomposition of the complex at room temperature (r. t.) was observed within a period of 6 hours. Its partition coefficient indicated that it was a lipophilic complex. The electrophoresis results showed that the complex was neutral. Biodistribution in mice indicated that the complex accumulated in the heart with high uptake and good retention. The heart/blood, heart/lung ratio was 6.28 and 1.35, respectively, at 60-minute post-injection, suggesting that it would be a potential myocardial perfusion imaging agent.

Synthesis and biodistribution of a new 99mTc nitrido complex as a potential myocardial and cerebral imaging agent

The bis( N-methyl, N-cyclohexyl dithiocarbamato) nitrido technetium-99m complex [ 99mTcN(MECHDTC) 2] (MECHDTC: N-methyl, N-cyclohexyl dithiocarbamato) has been synthesized through a ligand-exchange reaction. The two-step procedure consisted of an initial reaction of 99mTcO 4 − with succinic dihydrazide in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid as complexant, and successive addition of sodium salt of N-methyl, N-cyclohexyl dithiocarbamate. The radiochemical purity of the complex was over 90%, as measured by thin layer chromatography. No decomposition of the complex at room temperature was observed over a period of 6 h. Its partition coefficient indicated that it was a lipophilic complex. The electrophoresis results showed that the complex was neutral. Biodistribution in mice showed that the complex accumulated in the heart and brain with high uptake. The heart/blood, heart/lung and brain/blood ratios were 5.55, 2.11 and 1.10, respectively, at 30 min post-injection, suggesting that this compound is a potential myocardial and cerebral imaging agent.

Copolymerization of methyl 2-acetamidoacrylate and styrene in the presence of stannic chloride

Continuous variation method in UV revealed that methyl N-acetylaminoacrylate (MNA) and SnCl 4 formed the 1:1 complex. The copolymerization of MNA with styrene in tetrahydrofuran was carried out at 50 °C in the presence of SnCl 4. The resulting monomer reactivity ratios decreased with an increasing concentration of SnCl 4 added. This finding suggests that SnCl 4 participates in the propagation step of the copolymerization. Therefore, the copolymerization was analyzed by assuming terpolymerization of free MNA (M 1), complexed MNA (M 2), and styrene (M 3). The absolute copolymerization parameters were obtained as follows: k 11/ k 12=0.165, k 11/ k 13=3.04, k 22/ k 21=0.32, k 22/ k 23=0.103, k 33/ k 31=0.058, k 33/ k 32=0.001, Q 1=6.03, e 1=0.52, Q 2=88.57, and e 2=2.23. The complexed MNA is more reactive to polymer radicals with free MNA and styrene as the terminal unit than the free MNA. Very small values of k 22/ k 23 and k 33/ k 32 suggests that the copolymerization of the complexed MNA and styrene proceeds alternatingly.

Copper(II)/Tin(II) Reagent for Allylation, Propargylation, Alkylation, and Benzylation of Disulfides and Elemental Sulfur: New Insight into the “Copper Effect”

Organic bromides and iodides react with diorganodisulfides in the presence of stannous chloride and catalytic cupric halide, giving rise to corresponding unsymmetrical sulfides. Similar reactions but with elemental sulfur provide trisulfides and tetrasulfides. The reactions proceed by copper thiolate as principal reactive intermediate.

Highly regioselective addition of an ester enolate equivalent to α,β-unsaturated ketones: selective formation of both isomers derived from 1,2- and 1,4-additions using α-stannyl ester with additives

The reaction of α-stannyl ester with α,β-unsaturated ketones in the presence of stannous chloride (SnCl2) and chlorosilanes (Me3SiCl or Me2SiCl2) gave 1,2- and 1,4-addition products, respectively.

Synthesis, characterization and biodistribution of a99mTc nitrido complex as a potential brain perfusion imaging agent

The bis(N-cyclohexyl-dithiocarbamato) nitrido technetium-99m complex [99mTcN-(CHDTC)2] (CHDTC:N-cyclohexyl dithiocarbamato) has been synthesized through a ligand-exchange reaction. The two-step procedure involved the initial reaction of 99mTcO−4 with succinic dihydrazide (SDH) in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid (PDTA) as complexant, followed by the addition of sodium N-cyclohexyl dithiocarbamate dihydrate. The radiochemical purity of the complex was over 90% by thin layer chromatography. It was stable over 6 h at room temperature. Its partition coefficient indicated that it was a good lipophilic complex. Biodistribution in mice demonstrated that the complex accumulated in brain with high uptake and good retention. The brain uptake (ID%/g) was 2.91, 5.88 and 5.91 at 5,30 and 60 min post-injection respectively. The ratio of brain/blood in mice was high, 2.10 at 1 h post-injection. The results for the complex suggested that it could be a potential brain perfusion imaging agent. Copyright © 2000 John Wiley & Sons, Ltd.

Lewis acid-induced rearrangment of α-[bis(methylthio)methylene]ethyl-2-styrylcyclopropylcarbinols: unexpected formation of a novel bicyclo[3.2.1]octadiene framework

The α-[bis(methylthio)methylene]ethyl-2-styrylcyclopropylcarbinols 9a–c undergo a simple but unexpected skeletal rearrangement in the presence of stannic chloride in nitromethane to afford bicyclo[3.2.1]octadiene derivatives 10a–c exclusively in good yields. The structure of 10a was conclusively elucidated by X-ray diffraction studies. A possible mechanism governing the formation of 10 is proposed.

Copper(II)/Tin(II) Reagent for Allylation, Propargylation, Alkynylation, and Benzylation of Diselenides: A Novel Bimetallic Reactivity

Reactions of allyl, propargyl, benzyl, and alkynyl bromides with diorganodiselenides in the presence of stannous chloride and catalytic cupric halide result in the formation of corresponding unsymmetrical selenides in good to excellent yields via a novel dicopper(selenophenyl) intermediate.

Solvent extraction separation of platinum (IV) and palladium (II) by 2-ethylhexyl phosphonic acid mono -2-ethylhexyl ester (PC-88A)

Abstract Solvent extraction separation of platinum (IV) and palladium (II) was carried out with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) in toluene in the presence of stannous chloride. Platinum was quantitatively extracted from 0.5–2.25 M HCi with 5 × 10 −3 M PC-88A in toluene while palladium was extracted from 0.75–2.0 M HClHClO 4 acid mixture with 6 × 10 −4 MPC-88A in toluene. Platinum from the organic phase was stripped with 4 M HCl and determined colorimetrically by the stannous chloride method at 403 nm while palladium was determined by direct spectrophotometry in the organic phase at 586 nm. Platinum was quantitatively separated from palladium in the ratios of 1:1, 1:5 and 10:1. The proposed methods were successfully applied for the analysis of platinum and palladium in real samples.