Diacyl sulfides

The pyridinium salt formed from the acyl halide and pyridine in the absence of a carboxylic acid is able to diacylate water and hydrogen sulfide at -20° to give simple anhydrides and diacyl sulfides, respectively. ... 

Diacyl sulfides, preparation, 558 Dialdehydes, preparation, 286, 291 preparations listed in table 26, 303 Diamides, dehydration, 597 Hofmann degradation, 675 preparations listed in table 63, 580 Diamines, alkylation, 668... 

The SjSii ring system is susceptible to attack by nucleophiles, as is illustrated for 636. Examples of nucleophiles are alcohols (best with primary and secondary), 1563-1538 phenols,hydroxide ion, water, " and carboxylic acids. The boron compound 641 reacts with 636 to give the five-membered heterocycle 642. The electrophilic reagents, acetyl chloride and benzoyl chloride, react with tetraphenylcyclodisiladithianes to give the diacyl sulfide and dichlorophenyl-silane. ... 

Crystalline adducts from thioamides and aromatic acid chlorides ate well known. A very convenient synthesis of diacyl sulfides and thiocarboxylic acids - proceeds via adducts of thio-DMF with acid chlorides. 

The majority of syntheses of 1,4-thiazines involve the elimination of HL from species of type 11. Precursors of type 11a are not usually isolable compounds but are generated as intermediates. Two methods for the formation of such intermediates have been described one utilizes tetrahydro-1,4-thiazine-3,5-diones as starting materials, and the other requires diacyl sulfides and ammonia. Thus the synthesis of 2/f-l,4-thiazine (6), reported in 1948, was achieved by heating compound 16 at 450°C in the presence of powdered aluminum. Potentially, the procedure may be applied to the preparation of thiazines variously substituted at positions 2 and 6 however, the low yield (13%) achieved for the parent compound is a detraction. It was initially claimed that the reaction of diphenacyl sulfide with ammonia gave 3,5-diphenyl-4H-l,4-thiazine subsequent studies, however, revealed that the product was the 2//-tautomer 3,5-Diaryl-2/f-l,4-thiazines and... 

Heating 65, 68 (M=Zn, Cd R=CH3, tert-C H L=3,5-lutidine) gives metal sulfides in quantitative yields with the elimination of diacyl sulfides [249]. Treatment of mercury bis(thioacetate) with an aqueous solution of KOH gives mercury sulfide and potassium acetate [307]. Phenylmercury thiocarboxylates 70 react with AT-bromo- [148] and JV-iodo-succinimides [146] to give the corresponding acylsulfenyl halides (Scheme 5) (see Sect. 2.3.5). 

Diacyl sulfides a,/3-Ethylenesulfones a-KetoUiiolic acid esters a,jS-Oxidosulfoxides... 

Diacyl sulfides a,j8-Ethylenesulfones a-Ketothiolic acid esters a,/3-Oxidosulfoxides... 

Diacyl sulfides 26,618 —, cyclic s. Dicarboxylic acid thioanhydrides DIaldehydes... 

Diacyl sulfides 26, 618 —, cyclic s. Dicarboxylic acid thioanhydrides Dialdehydes -, ring closures 27, 384 with diamines 27, 384... 

Acoxythioethers Diacyl sulfides Episulfones a, P-Elhy lenesulf ones a-Ketodiiolic acid esters a,P-Oxidosulfoxides a-Thioketocarboxylic acids... 

Diacyl peroxides have been reduced with a variety of reduciag agents, eg, lithium aluminum hydride, sulfides, phosphites, phosphines, and haUde ions (187). Hahdes yield carboxyUc acid salts (RO) gives acid anhydrides. With iodide ion and certain trivalent phosphoms compounds, the reductions are sufftcientiy quantitative for analytical purposes. 

The photolysis of carboxylic acids and derivatives as lactones, esters and anhydrides can yield decarboxylated products 253>. This reaction has been utilized in the synthesis of a-lactones from cyclic diacyl peroxides 254) (2.34) and in the synthesis of [2,2]paracyclophane by bis-decarboxylation of a lactone precursor (2.35) 255). This latter product was also obtained by photoinduced desulfurization of the analogous cyclic sulfide in the presence of triethyl phosphite 256). 

W-1,4-Thiazines are formed when the sulfides (314) are reacted with ammonia (Scheme 47) (67JMC591). The 3,4-dihydrothiazine-3-thione (315) is converted by methyl iodide into the thiazinium salt (316), deprotonation of which yields a 4//-thiazine (317) (69JHC247). 1,4-Thiazine 1,1-dioxides are formed by the cyclodehydration of diacyl sulfones and ammonia (Scheme 48) (720S(52)135). 

Thiadiazoles are available by a nnmber of convenient general rontes inclnding cycUsation of N,N -diacyl-hydrazines, or 1,3,4-oxadiazoles, with phosphorus sulfides. 2-Amino-l,3,4-thiadiazoles are prepared via acylation of thiosemicarbazides and the parent compound is easily obtained from hydrogen sulfide and dimethylformamide azine. °... 

In 1994, successful isolations of various alkyl and aryl selenocarboxylic acids [14] enabled them to undergo exact reactions. Reactions of selenocarboxylic acids with dicyclohexylcarbodiimide (DCC) yield the corresponding diacyl selenides 25 and selenourea 26 quantitatively (Scheme 15) [14], as in reactions of thio- [44] and dithiocarboxylic acids [45,46]. In air,selenocarboxylic acids are immediately oxidized to afford the corresponding diacyl diselenides [13, 14]. Also, thio- and dithio-carboxylic acids readily react with aryl isocyanates to give acyl carbamoyl [47,48] and thioacyl carbamoyl sulfides [49, 50], respectively. 

Oxidation of Se-phenyl selenothioates 31 (R=i-Pr, Bu, Tol) with m-CPBA in ether gave a mixture of E- and Z-S-oxides (sulfines) 66, phenylseleno acyl sulfides 67, diphenyl diselenide, and diacyl disulfides 68 (only in the case of R=Tol) (Eq. 17) [12]. It was proposed that compounds 67 were formed by rearrangements of oxathiirane intermediates 69 [12]. 

The 1,4,5-thiadiazocines (136) can be prepared from diacyl- and dibenzoylhydrazines by initial conversion to their disodium salts with sodium amide in benzene, followed by condensation with 2-chloroethyl-3-chloropropyl sulfide in DMF (Equation (15)) <85MI 925-0l>. 

The rate of ionic decomposition of diacyl peroxides by sulfides (59) are (4-02NC H4C0)202 > (PhC0)202 > AC2O2. The fact that the softer sulfides are more effective is consistent with an initial displacement at the peroxy center by the S bases. 

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