A series of C-stannylated monosaccharide derivatives were prepared and their chemistry studied. Derivatives having a hydroxyl group ? to tin, i.e. methyl 4,6-0- benzylidene-2(3)-deoxy-2(3)-triphenylstannyl-?-D-allopyranosides [(1) and (2)] and 6-deoxy-l,2-0-isopropylidene-6-triorganostannyl-?-D-glucofuranose (3, R=Me, 4, R=Ph) were prepared by reaction of appropriate triorgano-tin-lithiums with epoxy sugars. Reactions of 3 with TFA, acetyl chloride, benzoyl chloride, ethyl chloroformate, sulphur dioxide and TCNE produced via elimination, 5,-6- dideoxy-1,2-0-isopropylidene-?-D-xylo-hex-5-enofuranose (15). Methyl-tin bond cleavage in 3, with formation of C-(dimethylhalogenostannyl)- monosaccharides, occurred on reaction with I2, Br2 or Pd(COD)Cl2. The product from the I2 reaction was unstable in solution and gave the elimination product 15. MeLi gave no reaction, and both SnCl4 and ClSO3H gave Me3SnCl and acetone as the only recognisable products. The triphenylstannyl derivatives 1, 2 and 4 underwent phenyl-tin cleavage with electrophiles. The 1,2:5,6-di-0-isopropylidene-3-C-(triorganostannyl)methyl-?-D-allofuranoses [R=Me, (11), Bu (12) or Ph (13)] were prepared by reaction of an appropriate (triorganostannyl)methy1-lithium with a keto-sugar. Substitution to form the C-(iodostannylated) monosaccharide occurred for all compounds on reaction with iodine. No elimination was obtained on reaction of 11 with TFA, deprotection being the predominant route. The elimination product was isolated from the attempted Pd-catalysed coupling of 12 with PhCOCl and from reaction of the methoxymethyl ether derivative 14 (R=Ph) with PhLi. No reaction was observed on treatment of 12 and 13 with organolithium reagents. Derivatives having a hydroxyl group ? to tin, the l,2:5,6-di-0- isopropylidene-3-C-triorganostannyl-?-D-allofuranoses [R=Me (9) and Ph (10)] were prepared via reaction of a triorganostanny1-lithium with a keto- sugar. Compound 9 gave predominant methyltin cleavage with I2, was partially deprotected by TFA and gave the methyl-coupled product, Me-R, on reaction with carbon electrophiles, R-Y, under Pd-catalysis. The triphenyltin derivative 10, decomposed on treatment with TFA, gave no reaction with phenyl-lithium and pheny1-tin cleavage with I2. The ?-alkoxy derivatives, l,2:5,6-di-0-isopropylidene-3-0-(triorgano-stannyl)methyl-?-D-glucofuranose [R=Me (5) and Ph (6)] and (triorgano-stannyl)methyl 2,3:5,6-di-O-isopropylidene-?-D-mannofuranoside [R=Me (7) and Ph(8)] were prepared via alkylation of a free hydroxyl by iodomethyl-triorganostannane. The triphenyl derivatives underwent pheny1-tin cleavage with I2 and TFA, while tin-lithium exchange occurred with PhLi to give a lithiated sugar which was trapped by a variety of reagents. Compounds 5 and 7 gave competitive cleavage of Me-Sn and R*OCH2-Sn bonds on treatment with halogens. Reaction with TFA, acetyl chloride and SO2 gave predominant reaction at the protecting groups and no reaction was observed for benzoyl chloride and ethylchlorofornate. Tin(IV) chloride gave mainly methyl transfer to tin to form MeSnCl3 and the C-chlorodimethylstannyl derivatives. Treatment with Pd(COD)Cl2 however, gave competitive transfer of methyl group and sugar moiety from tin to palladium. The crystal structures of 10, 13 and the iodo-derivative of 12 were determined; and the results of biological testing of 10 and 13 for antitumour activity and 1, 6 and 8 for plant protection properties are reported.

Bibliography: leaves [89-92]

The Port of Kaohsiung is the biggest harbor in Taiwan and also the fourth largest harbor in the world. There are several shipyards and fishing ports in the Port of Kaohsiung, therefore, the pollution of organotin should be very serious in the harbor area. In addition, there are Love River and Chien-Chen River pouring into the Port of Kaohsiung. This may be the second source of organotin pollution of the harbour of Kaohsiung. Seawater and sediment samples in the harbor of Kaohsiung were gathered in this research. Analysis on organotin contents were conducted to understand the distribution of the organictin in the Port of Kaohsiung. In seawater, the concentration of tributyltin (TBT) is between 170~480 ng/L, the concentration of dibutyltin (DBT) is between 150~400 ng/L and the concentration of monobutyltin (MBT) is between 80~283 ng/L. Working Duck and The Third Duck are among the serious areas of TBT pollution where the concentrations of TBT in seawater are over 350 ng/L. Concentrations of DBT and MBT are also the highest at the Working Duck. In the estuary areas, the concentrations of DBT and MBT are higher than TBT. It is probably due to the input of domestic sewage (Love River) and industrial wastewater (Chien-Chen River) which may bring extra DBT and MBT into the estuary areas. The highest TBT concentration in sediment is observed at Working Duck with average value of 25.3 mg/kg. This concentration is 4.5 times higher than that of Chien-Chen Fishing Port and 5.3 times higher than that of The Third Duck. All the concentrations of these three areas are over 10-d LC50 to bivalve (2.6 mg/kg) and amphipoda (2.1 mg/kg). The highest DBT and MBT concentrations are also observed in sediment of Working Duck, and the average concentration of DBT is 12.4 mg/kg and MBT is 9.7 mg/kg. In the estuary areas the concentration of organotins are lower than 1.2 mg/kg, therefore, the pollution of organotins is lesser serious in the estuary areas than the other sampling areas in Kaohsiung Harbor. The composition of organotins is mainly TBT in Working Duck, The Third Duck and Chien-Chen Fishing Port, and TBT accounts for more than 50%. TBT percentage decreases with sediment depth, however DBT and MBT percentage increases with sediment depth. It shows that TBT will be degraded for DBT and MBT gradually in the sediment. The trend that TBT percentage decreases with the sediment depth is not obvious in the estuary area, and the probable reason is that the source of DBT and MBT is not only from TBT degrading, but also from the input of city sewage and industry wastewater. According to this study, the content of organotins in sediment in the Port of Kaohsiung is indeed higher than other large-scale harbor (Barcelona and Port of Osaka). By comparing smaller areas, the content of organotins in Chien-Chen Fishing Port is also higher than marina of Hong Kong and German. It is concluded that the pollution of organotins in the Port of Kaohsiung is very serious in comparison with most other areas in the world.

Abstract Love River, the longest river in Kaohsiung City, 12 km in length, originates from Jen-Wu village of Kaohsiung County and goes into Kaohsiung Harbor from the northeast to southwest. Width of the river is increased from 14 m of the upstream to 130 m. Because there were active shipyards and many boats in Kaohsiung Harbor, TBT in paint as biocide to paint the ship will be released into seawater and cause the long-term contamination of organotin. It is possible that Love River may be polluted by the seawater from Kaohsiung Harbor for the intertidal zone of Love River reaches Chih-Ping Bridge. The goal of the present study is to analyze water and sediment of Love River in order to find out whether Love River has been polluted by organotin and, if yes, where the polluted source is. The samples were derivated with the Grignard reagent¡]n-pentylmagnesium bromide¡^and extracted by n-Hexane. Clean samples were concentrated to about 1 ml under a gentle stream of purified nitrogen gas. The final extracts¡]3£gl of each¡^were injected into a gas chromatograph with a flame photometric detector. The results reveal that TBT and DBT were predominant in the whole area of study. The concentration of TBT¡]29-360 ppt¡^was higher than DBT¡]0-292 ppt¡^in the riverwater. In the sediment, the concentration of DBT( 154-68800 ppb ) was higher than TBT ( 3650-30222 ppb )¡C Gransize between 0.053¢Pto 1.00¢P was predominant in the extent of sorption of organotin to sediments. The percentage of this gransize was from 82¢H to 98¢H. The major source of organotin pollution was Kaohsiung Harbor, but there were some other sources upstream of Chih-Ping Bridge. The polluted source of phentyltin was from the upstream of Chih-Ping Bridge and the branch of Love River¡]Canal, No2¡^. Comparing to other countries, organotin pollution was more serious in Love River. The concentration of TBT exceeded maximum allowable level of 20 ppt in accordance with regulations set by Britain. It is necessary to strengthen the regulation of organotin in Taiwan.

ABSTRACT A purge and trap concentrator coupled to gas chromatography-pulsed flame photometric detector(GC-PFPD) after in situ ethylation with sodium tetraethylborate(NaBEt4) was used to analyze organotin compounds in water samples. The sample glassware with 5.5 ml water sample, 1.5 ml derivatizing reagent as well as 2 ml buffer solution was installed to purge and trap system, and then all steps were performed automatically, including ethylation, purge and trap, concentration, chromatography seperation and detection. Parameters including NaBEt4 concentration, purge flow rate, purge time, desorb time, the pH of buffer solution, H2 flow rate and the voltage of photomultiplier tube(PMT) of PFPD , which influence the speciation of organotin compounds were optimized. Method detection limits for dibutyltin and tributyltin were 0.50 and 0.46 ng as Sn/L, respectively. The calibration graphs were linear up to 2 orders of magnitude. Surface water samples collected from fourteen different locations of Kaohsiung harbor were analyzed. The concentration of dibutyltin ranged from nondetected(ND) to 272.2 ng as Sn/L and tributyltin ranged from nondetected to 105.4 ng as Sn/L. Recovery percentage for dibutyltin and tributyltin ranged from 88.9-95.3 %.

Love River, 12 km in length from inland to the sea, is the longest river in Kaohsiung. Love River passes through the harbor of Kaohsiung and connects with the sea bring hidden ecological crises. Because there are persistent shipping from the whole world, several shipyards and fishing ports in the harbor of Kaohsiung, the pollution of organotin is very serious in the harbor area. It¡¦s possible that Love River may be polluted by the seawater from the harbor of Kaohsiung for the long intertidal zone and the estuary, in the harbor of Kaohsiung. Upstream sections may be also polluted by organotin compounds from domestic, industrial and agricultural wastewater. This study is not only collecting the surface and bottom riverwater during winter and summer, but also sampling the sediments in Love River. These samples are derivated with NaBEt4 and analyzed the concentration of organotin by gas chromatograph with a flame photometric detector. The results reveal that concentrations of MBT are 8.2-25.0 ng/L as tin, DBT are 3.3-17.1 ng/L as tin, TBT are 4.3-9.1 ng/L as tin in the riverwater. The concentrations of MBT are 12.5-69.2 ng/g as tin, DBT are 7.1-31.2 ng/g as tin, TBT are 15.8-22.6 ng/g as tin in the surface sediments. The pollution of organotin decrease from the harbor of Kaohsiung to the water gate in the downstream. A peak of pollution is found near the Yu-Cheng bridge in the upstream. The concentrations of the vertical distribution of sediments, MBT are as high as 61.2-273.2 ng/g as tin, DBT are 22.8-256.2 ng/g as tin, TBT are 8.6-168.4 ng/g as tin, it indicates that Love River was polluted extremely seriously by organotin compounds in the past. However, phenyltin compounds were not detected in these samples. As compared with previous reports, today the pollution of organotin compounds has been greatly reduced in Lover River. But it remains to be cared in order to reduce the potential ecological crises which are brought by the pollution.

Dialkylstannylene acetals are tin-containing species employed extensively as intermediates to facilitate high-yielding and regioselective monosubstitution reactions of diols or polyols with various electrophiles, which is an important application of organotin compounds in organic synthesis. Although an abundance of experimental studies of these reactions have been reported, the mechanism of the reaction has not been well defined. High-level theoretical methods are used in this thesis to investigate the chemistry of organotin systems at a molecular level. This involves the exploration of the geometry characteristics of the gas-phase structures along the reaction paths in order to understand the mechanism of the organotin-mediated alkylations of diols. Alkylation reactions which require strict conditions can be dramatically enhanced by the presence of nucleophiles. The effects of added nucleophiles were examined computationally by comparing reaction profiles obtained for alkylations of dimethylstannylene acetals in the presence of different nucleophiles.

No description available.

Thesis (M.Sc.) -- University of Adelaide, Dept. of Chemistry, 2001. / Bibliography: leaves [89-92].

A summary of the tin hydride method of generating radicals in organic synthesis is presented, followed by illustrative examples of other methods available for mediating radical reactions, with a particular emphasis on recent developments. This is followed by four chapters describing our efforts to introduce alternative methods for generating radicals. A range of l-alkylcyclohexa-2,5-diene-l-carboxylic acids have been prepared by Birch reduction-alkylation methodology and shown to generate the corresponding alkyl radical by thermal initiation with dibenzoyl peroxide. The 1-benzyl, cyclopentyl and t-butyl precursors (17,15, and 16 respectively), acted as sources of radicals which were trapped with cyclohexenone to give the corresponding 3-alkylcyclohexanone adducts in yields of 52%, 30% and 25% respectively. Addition products were also observed when acrylonitrile and vinyl benzoate were employed as the radical traps. 1-[2-(Cylohex-2-enyloxy)ethyl]cyclohexa-2,5-diene-l-carboxylic acid 32 and l-[2-(6,6- dimethylbicyclo[3.1. l]hept-2-en-2-ylmethoxy)ethyl]cyclohexa-2,5-diene- 1-carboxyhc acid 33 are new compounds which were prepared in four straightforward steps from cyclohexene and β-pinene respectively. The route leading to acid 32 involved the preparation of four new compounds and three new compounds were prepared during the synthesis of acid 33. When refluxed in benzene in the presence of dibenzoyl peroxide, carboxylic acid 32 generated a primary alkyl radical which cyclised to yield 7- oxabicyclo[4.3.0]-nonane in 55% yield. The tin-mediated cyclisation of 3-(2'- iodoethoxy)cyclohexene 36 yielded the same compound in 60% yield, in addition to 3- ethoxycyclohexene (12%). Similarly, carboxylic acid 33 generated a primary alkyl radical which cyclised to yield the new compound oxacyclopentane-3-spiro-2-6,6- dimethylbicyclo[3.1.1]heptane in 10% yield. The tin-mediated cyclisation of 6,6-dimethyl- 2-(2-iodoethoxymethyl)bicyclo[3.1.1]hept-2-ene 37 yielded the same spiro compound in 31% yield. EPR spectroscopic studies provided direct evidence for the formation of the cyclohexadienyl radicals from all of the carboxylic acids investigated. Carboxylic acids 15- 17 and l-[2-(ethenyloxy)benzyl]cyclohexa-2,5-diene-l-carboxylic acid 34 also generated alkyl radicals which were clearly observed by EPR spectroscopy. The carboxylic acid radical precursors would have yielded products in higher yields if the competitive loss of a hydroxyformyl radical did not occur. An account of our work directed towards the synthesis of l-phenylcyclohexa-2,5-diene-l- carboxylic acid 8 is given. Thus, 1,4-dihydrobiphenyl was deprotonated with BuLi, added to CO2 and the isomeric acid, 3-carboxylic acid-3,4-dihydrobiphenyl was removed by reacting with maleic anhydride to give the Diels-Alder adduct. 2-(Cyclohex-2-enyloxy)ethyl l-phenylcyclohexa-2,5-diene-l-carboxylate 24 was treated with dibenzoyl peroxide to afford 7-oxabicyclo[4.3.0]nonane in yields of 32-36%. A variety of N-carboalkoxy-l,2-dihydropyridines have been prepared from the reaction of pyridine and the appropriate chloroforniate in the presence of NaBH4. EPR studies have shown that these esters produce aza-cyclohexadienyl radicals on photolysis in the presence of di-t-butyl peroxide, but no decarboxylation was observed. These compounds do not generate alkyl radicals efficiently when reacted with dibenzoyl peroxide. In each case the major product identified was the corresponding benzoate ester, which resulted from the combination of an alkoxycarbonyl radical and a phenyl radical.