Preparation of Sulfur Compounds

A selection of the most important halides is show in Table 1 and routes to the preparation of sulfur compounds are shown in Fig. 1. With sulfur the fluorides are most stable and numerous, but Se and Te show an increasing range of heavier halides. Compounds such as S2C12 and S2F10 have S-S... 

Preparation of sulfur compounds. CAN acts as a catalyst for dithioacetalization ... 

Sodium suifite, acid (saturated) dissolve 600 g of NaHS03 in water and dilute to 1 liter for the preparation of addition compounds with aldehydes and ketones prepare a saturated solution of sodium carbonate in water and saturate with sulfur dioxide. 

Inclusion of a para acetyl group requires a somewhat different approach to the preparation of these compounds. Reaction of the diazonium salt from p-aminoacetophenone with sulfur dioxide affords the sulfonyl chloride, 203 this is then converted to the sulfonamide, 204, Elaboration via the carbamate with cyclohexyl-amine affords acetohexamide (205). ... 

Chlorpromazine (33) can probably be considered the prototype of the phenothiazine major tranquilizers. The antipsychotic potential of the phenothiazines was in fact discovered in the course of research with this agent. It is of note that, despite the great number of alternate analogs now available to clinicians, the original agent still finds considerable use. The first recorded preparation of this compound relies on the sulfuration reaction. Thus, heating 3-chlorodiphenylamine (30) with sulfur and iodine affords the desired phenothiazine (31) as well as a lesser amount of the isomeric product (32) produced by reaction at the 2 position. The predominance of reaction at 6 is perhaps due to the sterically hindered nature of the 2 position. Alkylation with w-C3-chloropropyl)dimethylamine by means of sodium amide affords chlorpromazine (33). ... 

A brown explosive form is produced if excess sodium is used in preparation of thiophene homologues—possibly because of sulfur compounds [1], As normally produced, it is a dry stable solid, but material prepared from acetylene and sodium-oil dispersions ignites in air [2],... 

The presence of sulfur compounds, especially thiophene, in the reagents leads to low yields and a dark-colored product. A good grade of thiophene-free benzene should be used. The benzene may be dried by distillation or by allowing it to stand over calcium chloride. The benzene which is recovered in this preparation may be used in future runs after it has been extracted with alkali, washed, and dried. Small amounts of carbon tetrachloride in the benzene do not interfere, since the quantities of benzene and carbon tetrachloride used are in excess of the relative quantity of the aluminum chloride. 

Dienones of this class are useful starting materials for the preparation of bicyclic compounds via Diels-Alder reactions1 4 and for the synthesis of small ring compounds.6 The 2,4-dienone can be converted quantitatively to the 2,5-isomer by treatment with fuming sulfuric acid and subsequent hydrolysis.6 The oxidation procedure is also applicable to the conversion of mesity-lene to mesitol or of isodurene to isodurenol,7 and can be used to convert tetramethyl ethylene quantitatively and directly to pinacolone.8... 

Electrophilic attack of the HN—C=X moiety in imidazolone derivatives at X (which has usually been sulfur) can result in 4//-imidazoles. This has been the most commonly used method for the preparation of these compounds. 

In comparison with other 1,3-dipoles that have been extensively explored in organic synthesis (7), sulfur-centered 1,3-dipoles (1-4) are rather uncommon species. However, within the last two decades, remarkable progress has been made regarding both methods of generation and synthetic applications. In particular, thiocarbonyl ylides (1) were established as key intermediates useful for the preparation of sulfur-containing heterocyclic compounds. General methods for the preparation of thiocarbonyl ylides and their chemical reactivity have been reviewed (8-11). 

Addition products have been obtained from aminochrome derivatives such as the semicarbazone, with sodium bisulfite. Recently Correia Alves reported the preparation of a compound described as adrenochrome semicarbazone sodium sulfonate (m.p. >300°) by treating a solution of adrenochrome monosemicarbazone (90) in sodium carbonate solution with sulfur dioxide at 40° for several days192 this compound was apparently different from the substance (m.p. 227-228°) obtained in a somewhat similar manner by Iwao193-194 and may be comparable to the compound (83) (m.p. > 300°) previously described in a Belgian patent179 (see Section IV,F). Iwao established the structure of his compound as the sodium salt of epinochrome-3-sulfonic acid monosemicarbazone (93).193... 

A recent study has led to a variety of episulfides which have antituberculosia activity against human-type tuberculosis.1-. 38 The episulfides prepared from uns turated butty adds and esters are reported to be useful as insecticides and fungicides This type of sulfur compound is also utilized in cosmetic preparations.81-32 New compounds, useful as lubricants30 have been prepared from the metal salts of these episulfides. 

Nitroguanidine may be prepared by the nitration of guanidine salts by means of nitric acid,1 or by the action of concentrated sulfuric acid upon guanidine nitrate.2 The nitration of guanidine thiocyanate yields a product which retains a small proportion of sulfur compounds, and Lhe nitration of the sulfate requires vigorous treatment and gives poor yields. The present procedure, which yields the alpha form,3 is simple and economical, and furnishes a good yield. 

Dialysis is a simple clean-up or purification process to remove unwanted low-molecular-weight compounds from solutions. The dialysis membrane consists of regenerated cellulose prepared from cotton linters by the viscose process. In addition to water, the membrane also contains glycerol and small amounts of sulfur compounds, which are removed during preparation of the tubing prior to use. 

For many years guanidine thiocyanate was the most easily prepared and the most commonly used of the salts of guanidine. Other salts were made from it by metathetical reactions. Nitro-guanidine, prepared from the thiocyanate by direct nitration with mixed acids, was found to contain traces of sulfur compounds which attacked nitrocellulose and affected the stability of smokeless powder, and this is one of the reasons why nitroguanidine powders did not come into early use. Guanidine thiocyanate is deliquescent. Strong solutions of it dissolve filter paper. 

The previously available methods for the preparation of such compounds were somewhat limited in their application. First, the oxidative coupling of 2 molecules of a heterocyclic-substituted toluene derivative in lie presence of sulfur results in the formation of symmetrical stil-benes,4,5 as shown by the synthesis of 4,4 -bis(benzimidazol-2-yl)stilbene (2). The disadvantages of this method are the high reaction temperatures necessary and the difficulties often involved in product workup. 

EXTENSIONS AND COMMENTARY The bottom line is that 5-TOM is a pretty heavy-duty experience, with more negative reports than positive ones. I have received no mentions of a completely ecstatic time, and not even very many neutral experiences. The consensus is that it wasn t worth the struggle. Some cramping, some nausea, and a generalized discomfort. And that one case of a catatonic response. An approach to possible individual variation in the metabolic handling of the sulfur atom is the rationale for the preparation of the compound TOMSO, and it is discussed there. 

These examples show the specificity of many reactions of organotellu-rium compounds that thereby prevent the simple extension of synthetic procedures developed for the preparation of sulfur and selenium heterocycles to their tellurium-containing analogs (see also 85MI6 86MI2). 

The use of soft metal ions to direct the course of reactions of sulfur compounds has been utilised in the preparation of nitriles from thioamides. The first step involves the alkylation of the thioamide to give the iminothioester, which is then converted to the nitrile on treatment with mercury(n) salts (Fig. 4-41). 

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