Sulfurous acid ester cyclic

Y-lactones, /raw -fused 32, 231 a-methylene-Y-lactones 32, 904 A -oxazolines 32, 278 sulfido compds. 31,542 sulfuric acid esters, cyclic 31,108... 

Acetic anhydride acetic acid Cyclic sulfuric acid esters from oxido compds. 

Ketones from cyclic sulfuric acid esters C... 

The reaction of peracids with ketones proceeds relatively slowly but allows for the conversion of ketones to esters in good yield. In particular, the conversion of cyclic ketones to lactones is synthetically useful because only a single product is to be expected. The reaction has been carried out with both percarboxylic acids and Caro s acid (formed by the combination of potassium persulfate with sulfuric acid). Examples of both procedures are given. 

In the first step an S03 molecule is inserted into the ester binding and a mixed anhydride of the sulfuric acid (I) is formed. The anhydride is in a very fast equilibrium with its cyclic enol form (II), whose double bonding is attacked by a second molecule of sulfur trioxide in a fast electrophilic addition (III and IV). In the second slower step, the a-sulfonated anhydride is rearranged into the ester sulfonate and releases one molecule of S03, which in turn sulfonates a new molecule of the fatty acid ester. The real sulfonation agent of the acid ester is not the sulfur trioxide but the initially formed sulfonated anhydride. In their detailed analysis of the different steps and intermediates of the sulfonation reaction, Schmid et al. showed that the mechanism presented by Smith and Stirton [31] is the correct one. 

Acidolysis of cyclic sulfites with sulfuric acid and ester interchange with dimethyl sulfate produce cyclic sulfates (104). 

Reaction of acetic acid and a catalytic amount of sulfuric acid at reflux temperatures for 6—8 hours with dihydromyrcene can cause rearrangement of the dihydromyrcenyl acetate to give a mixture of the cyclic acetates analogous to the cyclic formate esters (108). The stereochemistry has also been explained for this rearrangement, depending on whether (+)- or (—)-dihydromyrcene is used (109). The cyclic acetates are also commercially available products known as Rosamusk and Cydocitronellene Acetate. 

Ethers in which at least one group is primary alkyl can be oxidized to the corresponding carboxylic esters in high yields with ruthenium tetroxide.297 Cyclic ethers give lactones. The reaction, a special case of 9-16, has also been accomplished with CrO, in sulfuric acid.39" with benzyltriethylammonium permanganate,299 and with trichloroisocyanuric acid in the presence of an excess of water.300 In a similar reaction, cyclic tertiary amines (e.g., 28) can... 

Reactions and Uses. Ihe common reactions that o hydroxy acids undergo such as self- or bimolecular estcrihcation to oligomers or cyclic esters, hydrogenation, oxidation, etc. have been discussed in connection with lactic and hydroxyacetic acid A reaction that is of value lor the synthesis of higher aldehydes is tleearbonylation under boiling sulfuric-acid with loss of waler. 

The resultant sulfate ester can be converted to the alcohol by acid hydrolysis. If an acid-sensitive group is present, this hydrolysis is still successful through use of a catalytic amount of sulfuric acid in the presence of 0.5-1.0 equivalents of water with tetrahydrofuran as solvent. The use of base in the formation of the cyclic sulfates themselves can also alleviate problems associated with acid-sensitive groups.174175... 

Food, flavors consist of numerous compounds, none of which alone is characteristic of specific food. Classes of compounds which emcompass food flavors are - hydrocarbons (aliphatic, ali-cyclic, aromatic) carbonyls (aldehydes, ketones) carboxylic acids, esters, imides, anhydrides alcohols, phenols, ethers alkylamines, alkylimines aliphatic sulfur compounds (thiols, mono-, di- and tri-sulfides) nitrogen heterocyclics (pyrroles, pyrazines, pyridines) sulfur heterocylics (thiophenes, thiazoles, trithiolane, thialidine) and oxygen-heterocyclics (lactone, pyrone, furan). Discussion will be limited to striking developments in heterocyclics. 

Dihydro- 1,3-oxazines (398) are cyclic intermediates in the synthesis of a-amino-y-oxo acid esters by reaction of acyliminoacetates with enamines derived from six-membered ketones240. Sulfur-containing heterocycloadducts 399 and 400 have been prepared by [4 + 2] cycloaddition of enamines to heterocumulenes like thioacyl isocyanates and acyl isothiocyanates241. 

HILDAN HOE 2,671 INSECTOPHENE KOP-THIODAN MAT.TX NCI-C00566 NIA 5462 NIAGARA 5,462 OMS 570 RCRA WASTE NUMBER P050 SULFUROUS ACID, cyclic ester with 1,4,5,6,7,7-HEXACHLORO-5-NORBORNENE-2,3-DIMETHANOL THIFOR THIMUL THIODAN THIOFOR THIOMUL THIONEX THIOSULFAN THIO-SULFAN TIONEL TIOVEL... 

Esters have been prepared in 63-73% yields from several simple cycloalkyl and aryl alkyl ketones by reaction at room temperature with per-benzoic acid. The larger radical of the ketone appears as the alcohol fragment of the ester. Cyclic ketones are oxidized by potassium persulfate and sulfuric acid to esters from which o>-hydroxy aliphatic esters are obtained upon hydrolysis and reesterification. Peracetic acid in acetic anhydride converts salicylaldehyde to o-hydroxyphenyl formate (88%). ... 

Carboxylic and sulfonic acid groups import acidity to organic compounds. Most carboxylic acids and sulfuric acids are readily dissolved in water, and their titration with a base is straightforward. If solubility in water is not sufficient, the acid can be dissolved in ethanol and titrated with aqueous base. Aliphatic amines and many saturated cyclic amines can be titrated directly with a solution of a strong acid. Esters are determined by saponification with a measured quantity of standard base. The excess base is titrated with standard acid. 

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