Oxidation reactions Dibutyltin oxide

Ammonia Dibutyltin maleate Dibutyltin oxide Fluorosulfonic acid Phosphine Sodium ethylate Sodium hydride Tetrabutyl titanate Tetraisopropyl titanate p-Toluene sulfonic acid Zirconium butoxide catalyst, condensation reactions Dibutyltin diacetate Piperidine catalyst, conductive polymers Iron (III) toluenesulfonate catalyst, conversion of acetylene to acetaldehyde Mercury sulfate (ic) catalyst, copolymerization Di butyl ether catalyst, cracking Zeolite synthetic... 

PBT (50-10)/EVAc (9 % or 28 % VAc) (50-90) Internal mixer at 230 °C/selective solvent extraction/NMR/FTIR/SEM/model reactions/dibutyltin oxide catalyst (0-1 %)/blends optionally -1- PE Pesneau et al. 1997... 

Polyhydric alcohol mercaptoalkanoate esters are prepared by reaction of the appropriate alcohols and thioester using -toluenesulfonic acid catalyst under nitrogen and subsequent heating (16,17). Organotin mercapto esters are similarly produced by reaction of the esters with dibutyltin oxide (18). Pentaerythritol can be oxidized to 2,2-bis(hydroxymethyl)hydracryhc acid [2831-90-5] C H qO, ... 

Chemical Properties. Trimethylpentanediol, with a primary and a secondary hydroxyl group, enters into reactions characteristic of other glycols. It reacts readily with various carboxyUc acids and diacids to form esters, diesters, and polyesters (40). Some organometaUic catalysts have proven satisfactory for these reactions, the most versatile being dibutyltin oxide. Several weak bases such as triethanolamine, potassium acetate, lithium acetate, and borax are effective as stabilizers for the glycol during synthesis (41). 

Mercaptides are unchallenged as the ligand of choice for the other entities bonded to the tin, but carboxylates can also be used. Whereas a variety of mercaptans are used, the thioglycolic acid derivatives remain the largest single mercaptan. Dibutyltin bis(isooctyl thioglycolate) [25168-24-5] and butyltin tris(isooctyl thioglycolate) [25852-70A] are two common examples. These materials are produced by the reaction of the appropriate alkyl tin chloride or oxide, and the mercaptan. 

A prepolymer is made first by charging Pluracol E2000 [1000.0 g, 1.0 eq., poly(ethylene oxide), 56 OH, BASF] to a suitable container equipped with a mechanical stirrer and a nitrogen gas inlet. Flush the container with dry nitrogen and add Desmodur W (264.0 g, 2.0 eq., 4,4 -methylene-bis(cyclohexyl isocyanate), 31.8% NCO, Bayer). While maintaining a positive N2 pressure on the reaction mixture, stir and heat at 80°C for 2 h. Cool the product to room temperature and check the NCO content (theory = 3.32 %). It might be necessary to warm the highly viscous prepolymer to take samples for titration. To a portion of this prepolymer (250.0 g, 0.2 eq.), add Dabco T-12 (0.25 g, dibutyltin dilaurate,... 

Organotin compounds such as monobutyltin oxide, the main substance used, accounting for 70% of consumption, dibutyltin oxide, monooctyltin oxide, and dioctyltin oxide are used in certain esterification and transesterification reactions, at concentrations between 0.001% and 0.5% by weight. They are used in the production of substances such as phthalates, polyesters, alkyd resins, fatty acid esters, and adipates and in trans-esterifications. These substances are in turn used as plasticizers, synthetic lubricants, and coatings. Organo-tins are used as catalysts to reduce the formation of unwanted by-products and also provide the required colour properties (ETICA, 2002). 

Reaction of the 2-alkenylnicotinonitrile 305 with trimethylsilyl azide and dibutyltin oxide under microwave irradiation gives a mixture of the tetrazolylpyridine 306 (52%) and the tricyclic tetrazolonaphthyridine 307 (22%). Compound 306 may be cyclized to 307 by treatment with />-toluenesulfonic acid (Equation 105) <2006T1849> and the reaction 305 —> 306 —> 307 may be made into a one-pot procedure, with an overall yield of 68%. 

Monoalkylation of a vic-glycol.1 Selective monoalkylation or monoacylation of the vic-glycol group of dimethyl L-tartrate is possible by conversion to the O-stannylene acetal (1) by reaction with dibutyltin oxide. The acetal is converted selectively to a mono derivative (3) by reaction with an alkyl halide or acyl chloride (excess) and CsF (about 2 equiv.). KF or Bu4NF are less effective than CsF. 

Reaction of glycosyl thioimidate 79 with aa -dibromo-m-xylene in the presence of NaH as a base and 15-crown-5 as a supporting reagent allowed the intermediate 80 (Scheme 4.88). Treatment of the diol 81 with dibutyltin oxide in dry toluene and then reaction with 80 in the presence of tetrabutylammonium iodide afforded the desired O-linked intermediate 82. Activation of this compound with NIS-TMSOTf afforded 83 in a good yield. Hydrogenolysis followed by acetylation gave the desired disac-... 

Preparation of cyclodextrin derivatives substitution at a secondary hydroxyl group of the cyclodextrin annulus. Murakami and cowor-kers described a new and convenient method for the regioselective tosylation of the 2-hydroxyl groups of alpha, beta, and gamma cyclodextrin by means of a cyclic tin intermediate. The method is based on the reaction of dibutyltin oxide with 1,2-diols to form five-membered dibutyl-stannylidene derivatives. Useful yields of the 2-6>-tosyl derivatives of the cyclodextrins were obtained. 

Synthesis of PBHC. The procedure was the same as in the synthesis of PBH except 350g of BMA and 150g of HEA were used. After the copolymerization was finished, 147g of g, -caprolactone and 0.22g of dibutyltin oxide (DBTO) were added into the reaction product. The ring opening reaction of % -caprolactone in the presence of DBTO was carried out at 158-160 C for four hours, and then cooled to room temperature. 

Carbamates have been prepared by heating ethyl carbamate with a higherboiling alcohol in the presence or absence of catalysts [31-33], Aluminum iso-propoxide has been reported [34] to be an excellent catalyst for the interchange reaction between ethyl carbamate and benzyl alcohol. The interchange reaction is also effective for /V-alkyl carbamates as well as unsubstituted carbamates [35]. This catalyst is effective in preparing mono- and dicarbamates in excellent yields from primary and secondary alcohols and diols. Other effective catalysts are dibutyltin dilaurate [36], dibutyltin oxide [37], sulfuric acid or p-toluenesulfonic acid [31], and sodium metal (reacts with alcohols to give the alkoxide catalyst) [33]. 

Catalysts Catalysts are widely used for PU manufacture. Sometimes a combination of two or three catalysts is required to obtain the desired balance of reaction rates between compounds of differing active hydrogen activity. Metal compounds, especially organotin compounds, are much more efficient catalysts than tertiary amines for the -OH/NCO reaction. In addition to more commonly used dibutyltin(IV) dilaurate, dibutyltin(IV) diacetate, dialkyltin(IV) oxide or salts of divalent fin with a variety of carboxylic acids such as stannous octoate, hexoate and naphthenate etc. are available for this purpose. Combination of tin catalysts with tertiary amines has been reported to lead to a synergistic increase in catalytic activity. 

The diol (1 mmol) was refluxed with dibutyltin oxide (1 Eq) for 12 h in toluene (20 mL) in an apparatus for the continuous removal of water. The toluene was removed on a vacuum line at 20°C, and the residue was dried for 30 min under reduced pressure (0.1 ton). The residue was taken up in dry chloroform (10 mL), and N-bromosuccinimide (NBS 1 Eq) was added. The stirred reaction mixture was monitorec by TLC. The reaction was complete at times ranging from 2 to 30 min. The mixture was poured directly onto a column for separation using die eluant listed for each compound. 

Barbier reaction Samarium(II) iodide, 270 Benzoannelation Chromium carbene complexes, 82 Dicarbonylcyclopentadienylcobalt, 96 Ethyl (Z)-3-bromoacryIate, 130 Grignard reagents, 138 Methyl acrylate, 183 Methyllithium, 188 Ruthenium(III) chloride, 268 Benzoin condensation Benzyltriethylammonium chloride, 239 3-EthyIbenzothiazolium bromide, 130 Benzoylation (see also Acylation) Cadmium, 60 Dibutyltin oxide, 95 Birch reduction Birch reduction, 32... 

From oxidative cleavage of 1,2-diols and 1,2-amino alcohols Dibutyltin oxide, 95 By reaction of alkyl halides with sulfur-stabilized carbanions Methylthiomethyl p-tolyl sulfone, 192 From reduction of carboxylic acids Vilsmeier reagent, 341 From terminal alkenes by addition reactions... 

By cyclization reactions Camphor- 10-sulfonic acid, 62 Diethoxy triphenylphosphorane, 109 Diisobutylaluminum hydride, 115 B-3-Pinanyl-9-borabicyclo[3.3.1]-nonane, 249 Sodium nitrite, 282 a,(3-Epoxy alcohols I-Butyl hydroperoxide-Dialkyl tartrate-Titanium(IV) isopropoxide, 51 I-Butyl hydroperoxide-Dibutyltin oxide, 53... 

Norephedrine, 200 Organoaluminum reagents, 202 Organotitanium reagents, 213 9-(Phenylseleno)-9-borabicyclo-[3.3.1]nonane, 245 Tin(II) chloride, 298 Titanium(IV) chloride, 304 Trityllithium, 338 Trityl perchlorate, 339 Zinc chloride, 349 By other reactions Chloromethyl ethyl ether, 75 Dibutyltin oxide, 95 Samarium(II) iodide, 270 Tributyltin hydride, 316 Hydroxy amides a-Hydroxy amides... 

Metal chelates of 8-hydroxyquinoline such as (111) with photoconductive properties are reported to be useful in electrophotographic systems.233 The incorporation of a tin complex into a photo-conductive zinc oxide layer is stated to reduce dark decay . In other words, the electrostatic charge applied to the photoconductor has a longer lifetime. Two of the complexes disclosed for this application are (112) and (113). These compounds are prepared from dibutyltin oxide by reaction with 2-mercaptopropionic add and thioglycolic acid, respectively 234... 

In 1974, David18 reported that cyclic stannylenes (97), formed by reaction of 1,2-diols (96) with dibutyltin oxide— -Bu2SnO—in refluxing benzene with azeotropic elimination of water, reacted with Br2 in solution at room temperature at titrating speed, leading to a-hydroxyketones (98). 

Piperonal lc (5 mmol), hydroxylamine hydrochloride (6 mmol), and n-dibutyltin oxide (0.5 mmol) were admixed with alumina (1 g) and exposed to microwave irradiation at 450 W (BPL, BMO-700T) for an appropriate time. After complete conversion, as indicated by TLC, the reaction mixture was filtered and the residue washed with dichloromethane (2x15 mL) which was then concentrated in vacuo. The resulting solid was recrystallized in ethanol to give 3,4-methylene-dioxybenzonitrile 2c in 92% yield as a white solid, mp 68-70 °C. The liquid products were purified by column chromatography on silica gel (Merck, 100-200 mesh, ethyl acetate-hexane, 1 9) to afford the corresponding nitriles in pure form. 

Spiroorthocarbonates were obtained by coupling of cyclic tin adduct 251, prepared from 1,2-dihydroxymethyl-benzene and dibutyltin oxide, with thiocarbonate 252. Reaction of the resulting orthocarbonate 253 with potassium A/z-butoxide in toluene afforded spiroorthocarbonate 254 (Scheme 77) <2003BKC1371>. 

Benzyl 4, 6 -0-benzylidene-P-lactoside with five free hydroxyl groups was converted to the dibutylstannylene intermediate by azeotropic removal of water from its mixture with 2.5 molar equiv. dibutyltin oxide in benzene, the reaction with benzyl bromide in the presence of tetrabutylammonium bromide then gave the 2,3 -di-0-benzyl derivative in 52% yield [139]. When the 3, 4 -0-isopropylidene analog was treated with 1.2 molar equiv. only, the 2-O-benzyl derivative was the main product [150]. 

Regioselective acylations can also be achieved by the stannylene procedure but, in general, selectivities are not as high as for alkylations. For example, treatment of methyl P-D-galactoside with dibutyltin oxide followed by reaction with benzoyl chloride results in the formation of a mixture of methyl 6-O-benzoyl-P-D-galactoside (53%) and methyl 3,6-O-di-benzoyl- P-D-galactoside (21 %).40... 

Dodecyl 4-pent-2-enyl Sulfide. Dibutyltin oxide (21.37 grams, 0.08589 mole) reacted with 34.7 grams (0.1715 mole) of dodecyl mercaptan in 150 ml. of toluene at reflux for 39 minutes when the evolution of water had ceased. The reaction product was charcoaled, filtered, and concentrated to constant weight at 55 °C. and < 1 mm. The yield of colorless dibutyltin bis(dodecylmercaptide) was 54.7 grams (theory 54.53 grams). This mercaptide, 1.5023 grams (0.00494 mole) of dibutyltin dichloride, and 17.96 grams (0.1718 mole) of 4-chloro-2-pentene reacted in 250 ml. chlorobenzene solution for 7.2 hours when analysis of a sample of the reaction product for chloride showed the reaction to be virtually completed. 

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