Dibutyltin Oxide Research Articles

High Impact, Amorphous Terephthalate Copolyesters of Rigid 2,2,4,4-Tetramethyl-1,3-cyclobutanediol with Flexible Diols

A new family of terephthalate-based copolyesters has been found to exhibit high impact resistance combined with good thermal properties, ultraviolet stability, optical clarity, and low color. These engineering thermoplastic compositions were prepared using conformationally rigid cis/trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol [CBDO] and flexible C2−C4 aliphatic glycols. The copolymers were amorphous when the CBDO (∼50/50 cis/trans) content was about 40 to 90 mol % of total diol. Glass transition temperatures were 80−168 °C, depending on the proportion of rigid CBDO units. Impact resistance was inversely proportional to CBDO content, and notched Izod values as high as 1000 J/m were obtained. Both high Tg (>100 °C) and high impact (250−750 J/m) can be realized simultaneously for compositions containing about 50−80 mol % CBDO. Accelerated weathering indicated good inherent resistance of 1,3-propanediol/CBDO copolyterephthalate to yellowing under ultraviolet radiation. Dibutyltin oxide was more effective fo...

Synthesis and spectroscopic studies of organotin(IV) complexes of biologically active Schiff bases derived from sulpha drugs

The reaction of dibutyltin oxide with Schiff bases derived from sulpha drugs in 1:1 molar ratio leads to the formation of a new series of organotin(IV) complexes. An attempt has been made to probe their structure on the basis of UV, IR, NMR (1H,13C and 119Sn) and Mossbauer spectral studies. A few representative compounds have also been screened for bactericidal activity and found to be quite active in this respect. Copyright © 2000 John Wiley & Sons, Ltd.

Catalytic aspect of chemical modifications of polymers by transesterification: NMR study with model compounds

The catalytic activity of different compounds (dibutyl tin oxide, titanium tetrabutoxide, zirconium tetraethoxide, and para-toluenesulfonic acid) for transesterification reactions between polymers was studied. This study was carried out on three different reactions: between two model compounds (methyl benzoate and octyl acetate), between a polymer and a model compound (ethylene-vinyl acetate copolymer and methyl benzoate), and for crosslinking of ethylene-vinyl acetate copolymer with dimethyl terephthalate. For these three reactions dibutyl tin oxide presented the higher catalytic activity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1556–1562, 2001

One-Pot p-Toluenesulfonylation of Adenosine and Methyl Glycosides with a Substoichiometric Amount of Organotin Mediators

ABSTRACT A substoichiometric amount (10-20 mol%) of dibutyltin dichloride 1 was found to be effective for promoting the regioselective 2'-O-tosylation of adenosine 2 with TsCl in a one-pot manner, wherein a turnover step for tin dichloride 1 was involved. Dibutylchlorotin hydroxide 7, dibutyltin oxide 8, bis(dibutylchlorotin) oxide 10, its hydroxy congener 12, and tributyltin chloride 14 were also effective in a substoichiometric amount for the 2'-O-tosylation of the nucleoside 2. The method was applicable to some methyl glycopyranosides. The tosylation with tin dichloride 1 was not sensitive to the presence of water in the reaction mixture. Possible reaction pathways are discussed.

New polymer syntheses. 107. Aliphatic poly(thio ester)s by ring-opening polycondensation of 2-stanna-1,3-dithiacycloalkanes

We prepared 2,2-dibutyl-2-stanna-1,3-dithiacycloalkanes from dibutyltin oxide and α,ω-dimercaptoalkanes. Heterocycles with five-, six-, seven-, or nine-ring members were used as bifunctional monomers for polycondensations with aliphatic dicarboxylic acid chlorides. These polycondensations conducted in bulk were highly exothermic and yielded poly(thio ester)s with number average molecular weights (Mn's) in the range of 5000–30,000 Da. These poly(thio ester)s proved to be rapidly crystallizing materials with melting temperatures in the range of 90–150 °C. In addition to the success of the new synthetic approach, two interesting and unpredictable results were obtained. All volatile species detectable by matrix assisted laser desorption induced-time of flight (MALDI-TOF) mass spectrometry were cyclic oligo- and poly(thio ester)s. Second, several polyesters showed a reversible first-order change of the crystal modification as identified by differential scanning calorimetry measurements and X-ray scattering with variation of the temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3656–3664, 2000

Structure elucidation of the dibutylchlorostannyl intermediate during dibutyltin oxide-mediated acylation of sugars

119Sn NMR and APcI-MS indicate the presence of a dimeric species as the dibutylchlorostannyl intermediate after dibutyltin oxide-mediated bezoylation of methyl 4,6- O-benzylidene-α- d-glucopyranoside. The stannyl groups in the dimer dismutate to form a dialkoxystannyl species loosely complexed to dibutyltin dichloride. This species and its isomer were also prepared by treating the benzoylated sugar with bis(dibutylchlorotin) oxide. The dialkoxytin complex and isomer was also prepared by treating the benzoylated sugar with dibutyltin oxide.

3-Hydroxyphthalide and its adduct with dibutyltin oxide

3-Hydroxyphthalide, C 8 H 6 O 3 , reacts with dibutyltin oxide to give bis{μ 3 -oxo-(μ-2-formylbenzoato-O:O')-(2-formylbenzoato-O)bis[dibutyltin(IV)]}, [Sn 4 (C 4 H 9 ) 8 (C 8 H 5 O 3 ) 4 (μ-O) 2 ], in which the four Sn atoms are all five-coordinated to three O and two C atoms arranged at the corners of a distorted trigonal bipyramid. The equatorial Sn-μ 3 -O distances are in the range 2.039(2)-2.048 (2) A and are significantly shorter than the axial Sn-μ 3 -O distances of 2.170(3) and 2.182 (2) A. The Sn-O carboxylate bonds are all axial and have distances in the range 2.204 (3)-2.271 (3) A, which are inversely correlated with the respective C-O bond distances. The mean Sn-C distance is 2.136 (6) A. 3-Hydroxy-phthalide undergoes ring opening to give the anion of 2-formylbenzoic acid which bonds to the Sn atoms. The structure of 3-hydroxyphthalide is stabilized by O-H...O hydrogen bonds [O...O = 2.766 (1) A] which link the molecules in a zigzag chain parallel to b.

Dibutyl Tin Oxide Mediated, Regioselective Alkylation and Acylation of Siloxane Protected Glycopyranosides

Dibutyl Tin Oxide Mediated, Regioselective Alkylation and Acylation of Siloxane Protected Glycopyranosides

The reaction of di-n-butyltin oxide with hexafluoro-2,2-bis(4-carboxyphenyl)propane

The reaction of hexafluoro-2,2-bis(4-carboxyphenyl)propane with tetrabutyldipropoxydistannoxane, formed in situ from dibutyltin oxide and n-propanol in benzene, yields a compound the structure of which is a strained macrocycle with a single dicarboxylate moiety.

Effect of Dimethylformamide on the Ring Opening Insertion Polymerization of ε-Caprolactone

Ring-opening insertion polymerization of ε-caprolactone is retarded in dimethylformamide when catalysts such as dibutyl tin oxide, zinc acetate and titanium tetrabutoxide are employed.

Dibutyltin Oxide Catalyzed Selective Sulfonylation of α-Chelatable Primary Alcohols

The reaction of substituted glycols with catalytic dibutyltin oxide, stoichiometric p-toluenesulfonyl chloride, and triethylamine in CH2Cl2 resulted in the complete and rapid sulfonylation at the primary alcohol. The α-heterosubstituted primary alcohol moiety appeared optimal for best results, supporting the intermediacy of a five-membered chelate. The role of the amine is discussed, in addition to catalyst requirements and solvent effects.

Chemical modification of poly(styrene-co-acrylonitrile) with 2-aminoalcohols and 3-aminoalcohol

Nitrile groups of poly(styrene-co-acrylonitrile) (SAN) can be converted to 2-substituted Δ 2 -oxa-zoline using 2-aminoethanol. The formation of oxazoline in SAN can be significantly increased through addition of substituted aminoalcohols like 2-amino-2-ethylpropane-1,3-diol and 2-aminobutanol and through reaction with 3-aminopropanol using dibutyltin oxide as catalyst. Using this procedure, dihydro-4H-oxazine can be easily produced from 3-aminopropanol due to the lower ring tension in comparison with the five-membered oxazoline ring.

Reaction of dibutyltin oxide with amides in presence of traces of water: multinuclear NMR study and mechanism

The product of the reaction of primary and secondary amides with dibutyltin oxide is shown to be a dimeric 1,3-diacyloxytetrabutyldistannoxane. The reaction was studied in bulk with model amides at 180°C, avoiding perfect anhydrous conditions, in view to be transposable to transamidification with reactive extrusion process. The formation of an intermediate compound of the type 1-acyloxy-3-alkylaminotetrabutyldistannoxane is pointed out. With an excess of amide, the presence of water leads to the dimeric 1,3-diacyloxytetrabutyldistannoxane. Without an excess of amide, the hydrolysis of this intermediate leads to a more complex tetrastannoxane structure associated in a more or less perfect ladder-like structure including partially hydrolyzed and condensed forms of the distannoxane. The dimeric 1-acyloxy-3-alkoxytetrabutyldistannoxanes resulting from the reaction of esters with dibutyltin oxide are shown to give a similar stannoxane structure after hydrolysis. All the products were characterized in solution by 1H-, 13C- and 119Sn-NMR spectroscopy. On the basis of the spectroscopic analysis, a mechanism of the reaction is proposed and discussed.

Effect of Dimethylformamide on the Ring Opening Insertion Polymerization of ɛ-Caprolactone

Ring-opening insertion polymerization of Iµ-caprolactone is retarded in dimethylformamide when catalysts such as dibutyl tin oxide, zinc acetate and titanium tetrabutoxide are employed.

Dibutyltin derivatives of 2,6-pyridinedicarboxylic acids. Crystal structures of bis(diisopropylammonium) tris(2,6-pyridinedicarboxylato)bis(dibutylstannate) trihydrate and bis(diisopropylammonium) bis[aquadibutylstannyl(2,6-pyridinedicarboxylato-4-olate)

Abstract Dibutytlin oxide condenses with diisopropylammonium hydrogen 2,6-pyridinedicarboxylate to form bis(diisopropylammonium) tris(2,6-pyridinedicarboxylato)bis(dibutylstannate) trihydrate, whose crystal structure consists of a three-dimensional hydrogen-bonded framework of ammonium cations, stannate anions and water molecules. In the dianion, the carboxyl –CO2 groups of the central 2,6-pyridinedicarboxylato member are each chelating an O,N,O-dibutyl(2,6-pyridinedicarboxylato)tin molecule flanking it; one molecule has its C2Sn skeleton in an almost linear alignment [C–Sn–C 173.8(6)°; Sn–O 2.423(8) Å, 2.457(9) Å] whereas the other has a bent C2Sn skeleton [C–Sn–C 158.0(7)°] arising from anisobidentate chelation [Sn–0 2.303(7) Å, 2.785(8) Å]. Their tin atoms are seven-coordinate in trans-C2SnNO4 pentagonal bipyramidal geometries. Dibutyltin oxide reacts with diisopropylammonium hydrogen 4-hydroxy-2,6-pyridinedicarboxylate to yield centrosymmetric bis(diisopropylammonium) bis[aquadibutylstanny(2,6-pyridinedicarboxylato-4-olate)]. The water-coordinated tin atom [Sn–Owater 2.409(3) Å] in the bis[aquadibutylstanny(2,6-pyridinedicarboxylato-4-olate)] dianion, whose negative charges reside on the 4-substituent oxygen atoms, is also seven coordinate [C–Sn–C C 159.6(2)°]. The dianions are linked to adjacent dianions through the diisopropylammonium counterions [N … Oesteryl 2.954(4) Å, N … Ohydroxyl 2.719(5) Å)] to result in a one-dimensional hydrogenbonded chain structure.

A new diaza heteroaromatic crown of 3,5-disubstituted 1H-pyrazole which forms solid dinuclear complexes with lipophilic phenethylamines

The cyclic stannoxane obtained from N-methyldiethanolamine and dibutyltin oxide reacts with 1H-pyrazole-3,5-dicarbonyl dichloride to afford the new 26-membered diaza tetraester crown 3. In neutral medium, the above crown forms 1:2 solid dinuclear complexes with phenethylamine (3a) and homoveratrylamine (3b), which, after crystallization from acetonitrile, were isolated in high yield (90% and 85%, respectively). The 3, 3a, and 3b structures were identified from their analytical and spectroscopic (1H, 13C NMR, and MS (FAB)) data. The spectroscopic properties of 3a and 3b are demonstrating that, in each complexation centre, simultaneously to the strong participation of the four pyrazole nitrogens, an additional weaker interaction between the aliphatic nitrogen of the side chain and the amine is involved. Comparison of the total interaction energies calculated (GenMol software) for phenethylamine-derived complex (3a) and homoveratrylamine-derived one (3b) suggests that the o-dimethoxy substitution of the guest aromatic ring could be improving the stability of 3b in relation to 3a.Key words: diazacrown, 1H-pyrazole, dinuclear, complexes, phenethylamines.

Kinetics of polyesterification of adipic acid with 1,3‐butanediol

AbstractThe kinetics of non‐catalyzed, acid catalyzed and alkyltin catalyzed polyesterification of adipic acid with 1, 3‐butanediol as a model for polymeric ester synthesis was followed at 180°C and 215°C by monitoring of carboxyl, hydroxyl, and water content of the reaction system. The rate constants of the three processes were calculated using a simulation method. The process is kinetically controlled during the first 4–10 h (down to AV ≅ 20 mg KOH/g, conversion 95%) and then thermodynamically controlled by elimination of water from the system. Methyltin derivatives, especially trichloride, are more active catalysts but dibutyltin oxide can be used with good results. The model study suggests that addition of the catalyst at the beginning of the process and applying a vacuum (pressure 60 Torr) will reduce the reaction time in half, compared with adding catalyst at AV ≅ 20 mg KOH/g and using no vacuum.

Glycosylation via locked anomeric configuration: stereospecific synthesis of oligosaccharides containing the β- d-mannopyranosyl and β- l-rhamnopyranosyl linkage

cis-1,2-Stannylene acetals of d-mannose and l-rhamnose, formed preferentially from the free sugars treated with dibutyltin oxide, are capable of displacing the trifluoromethanesulfonyl (triflyl) leaving groups in carbohydrates to give, with retention of configuration at the anomeric center in the nucleophile, cis-1,2-linked oligosaccharides. In the case of secondary triflates, the new glycosidic linkage is formed with complete inversion of configuration in the electrophile. Both the reactivity of the electrophile and nucleophilicity of oxygens in the stannylene complex affect the overall outcome of the reaction. From the comparison of results of a number of glycosylations via stannylene acetals, it appears that nucleophilicity of oxygens involved in the cis-1,2-acetals decreases in the order: equatorial anomeric > equatorial non-anomeric > axial anomeric. Consequently, treatment of the stannylene acetal prepared from d-mannose (mainly the cis-1,2-stannylene compound in admixture with a small proportion of the cis-2,3-stannylene acetal) with methyl 2,3,4-tri- O-benzoyl-6- O-trifluoromethanesulfonyl- α- d-glucopyranoside yielded, in addition to the expected β- d-mannopyranoside (major), a product of non-anomeric alkylation at O-3. On the other hand, glycosylation of the stannylene acetal derived from maltose with methyl 2,3,6-tri- O-benzoyl-4- O-trifluoromethanesulfonyl- α- d-galactopyranoside gave almost exclusively a non-glycosidically, (2→4)-linked pseudo-trisaccharide. Combination of the glycosylation via locked anomeric configuration with conventional glycosylations, to yield higher oligosaccharides, is also demonstrated.

Macrocycles, 1. Macrocyclic polymerizations of (thio)lactones - stepwise ring expansion and ring contraction

2,2-Dibutyl-2-stanna-1,3-dioxacycloalkanes were prepared from dibutyltin oxide and 1,2-ethanediol, 1,3-propanediol or 1,4-butanediol. These tin heterocycles reacted stoichiometrically with double molar amounts of γ-thiobutyrolactone by a stepwise insertion. In contrast to γ-thiobutyrolactone an excess of e-thiocaprolactone resulted in additional insertion steps, i.e., polymerization of the thiolactone. Analogous insertion reactions were performed with a spirocyclic stannoxane derived from pentaerythritol. With e-caprolactone macrocyclic polymerization took place without stoichiometric intermediates. When the 2,2-dibutyl-stanna-dioxepane was reacted with an equimolar amount of 1,3-dithian-2-one, the insertion step was immediately followed by a ring contraction reaction yielding 2-stanna-1,3-dithiane and trimethylene carbonate which polymerized immediately. The application of this reaction sequence to macrocyclic stanna poly(e-caprolactone) yielded tin-free macrocycles along with 2,2-dibutyl-2-stanna-1,3-dithiane. This reaction sequence allows the synthesis of nontoxic, biodegradable macrocyclic polyesters.

Selective oxidation of 1,2-diols by electrochemical method using organotin compound and bromide ion as mediators

A new electrochemical method for a selective oxidation of 1,2-diols to keto alcohols was explored. The method used dibutyltin oxide and bromide ion as mediators, and the oxidation was found to proceed effectively at 0°C under neutral conditions. Under these reaction conditions, 1,2-cyclohexanediol was selectively oxidized even in the presence of primary and secondary alcohols.