Bis sulfur

Sulfonation with sulfur trioxide, pyridine sulfur trioxide, pyridine bis-sulfur trioxide, and dioxane sulfur trioxide, which are useful sul-fonating agents for acidophobic substances, have been applied to the thiophene seriesd At room temperature the 2-monosulfonic acid (isolated as the barium salt) is obtained in 86% yield. Higher temperatures lead to a disulfonic acid. However, sulfonation with chloro-sulfonic acid appears to be more convenient,as the sulfonyl chloride obtained can be used directly for the preparation of derivatives. 

The sulfonating actions of pyridine-sulfur trioxide, pyridine-bis sulfur trioxide and dioxane sulfur trioxide on 2,5-dimethyIthiophene have been compared. Yields of 95% monosulfonic acid were obtained with the latter two reagents, whereas pyridine sulfur trioxide yielded only 75%. 2-Methyl-3,5-diphenylthiophene resists formylation and SnCl4 Catalyzed acylation in contrast to 2,3,5-trimethylthiophene, which is formylated and acylated quite easily. 

Bats, 54 Batteries, 54 Benzene isomers, 55 Benzyl compounds, 55 Bis(arenediazo) oxides, 56 Bis(arenediazo) sulfides, 56 Bis(difluoroamino)alkyl nitrates, 56 Bis(fluorooxy)perhaloafkanes, 57 Bis(sulfur)diimides, 57 Bitumen, 57 Bleaching powder, 57 Bleve, 58... 

Another sulfur allotrope - cyclodecasulfur (Sio) - also reacted with norbomene under milder conditions to furnish the trithiolane 59 (R = H) as the unique reaction product in 85% yield <1999TL7961>. Similarly, the reaction of S10 with norbornadiene produced a trithiolane adduct 60 in good yield as well as a new bis-sulfurated compound 61 (Equation 21) <1999TL7961>. Reactions with Sg under the same conditions produced only traces of the expected products. 

S03-0(CII2CH2)20 Dioxane-bis-(sulfur trioxide), 2 174 S04HN0 Nitrosylsulfuric acid, 1 55... 

Heating the 7-acetyl derivative 536 in 6 Af hydrochloric acid gave the deacetylated bicycle 537 in 97% yield. The reaction of 536 with phosphorus pentasulhde in boiling pyridine for 0.5 hr afforded the bis(sulfurated) derivative 538 in 71 % yield (71BCJ153). 

SOsNa2(and -fTHaO) Sodium sulfite, 2 162, 164, 165 S0s-0(CH2CHj)2O Dioxane-sul-fur trioxide, 2 174 2S03-0(CH3CH2)20 Dioxane-bis(sulfur trioxide), 2 174... 

A solvent-based silane system which has proven to give excellent corrosion resistance in un-painted state is the mixture of the bis-sulfur and bis-aminosilanes with the ratio 3 1. This system is able to protect many metals, for instance, aluminum, HDG steel and Mg alloys. Fig. 5 presents the scanned... 

Silane Bis-sulfur Bis-sulfur BTSE Bis-sulfur or bisbenzene... 

Both mixtures of silanes as well as individual silanes have been investigated for use in superprimers. Usually, hydrophobic bis-silanes such as BTSE and bis-sulfur silane, shown in Fig. 4, work well in the primers. 

C3sH3oNi,NiOP2 f Azidonitrosylbis(triphenylphosphine)nickel, 37B, 659 C3 6H3oNiOi,P2S2 f Bis (sulfur dioxide) bis(triphenylphosphine)nickeKO), 45B, 1380... 

C43H36BF4IIrN02P2 f lodocarbonylnitrosylbis(triphenylphosphine)iridium tetrafluoroborate - benzene, 34B, 614 C4 3H3 s04P2PtS2 f Bis(sulfur dioxide)bis(triphenylphosphine)platinum toluene solvate, 42B, 984... 

To circumvent the use of highly toxic sulfur dioxide gas, Willis and coworkers explored amine-S02 complexes as sulfur dioxide surrogates. Willis demonstrated that l,4-diazabicyclo[2.2.2]octane (DABCO)-bis sulfur dioxide (DABSO, Figure 13.2) is a useful replacement for sulfur dioxide gas for the formation of sulfonamides from Grignard reagents (Scheme 13.15). DABSO is commercially available and may be prepared quantitatively from DABCO and sulfur dioxide. 

The desired [2,3]-sigmatropic rearrangement of a bis-sulfur cyano-stabilized lithium salt did not proceed (eq 7) without the addition of 25% HMPA. Sometimes higher 0/C-alkylation ratios are obtained in THF-HMPA. ... 

In a typical procedure, the thiol-epoxy click reaction near quantitative yields can be employed as a polymerization reaction for preparing linear polymer chains substituted with free hydroxyl groups. Khan et al. [16] reported that the linear polymer can be easily constructed by step-growth polymerization of the commercially available diepoxide (AA-type) and bis-sulfur (BB-type) monomers using lithium hydroxide (base catalysts) as the polymerization catalyst. (Figure 8.3)... 

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