Thioethers from esters

SECTION 128 Ethers, Epoxides, and Thioethers from Esters... 

SECTION 128 ETHERS, EPOXIDES AND THIOETHERS FROM ESTERS... 

A procedure, which has been used successfully for the synthesis of dialkyl thioethers from thioacetamide has been extended to the preparation of a range of 5-alkyl thiocarboxylic esters [35] (Table 4.20). The intermediate 5-acyl ethaniminium salt (Scheme 4.14) is not stable and is converted directly into the 5-alkyl thioester. The choice of catalyst affects the yield of the thioesters. Thus, 5-n-octyl thiobenzoate... 

Kobayashi et al. found that lanthanide triflates were excellent catalysts for activation of C-N double bonds —activation by other Lewis acids required more than stoichiometric amounts of the acids. Examples were aza Diels-Alder reactions, the Man-nich-type reaction of A-(a-aminoalkyl)benzotriazoles with silyl enol ethers, the 1,3-dipolar cycloaddition of nitrones to alkenes, the 1,2-cycloaddition of diazoesters to imines, and the nucleophilic addition reactions to imines [24], These reactions are efficiently catalyzed by Yb(OTf)3. The arylimines reacted with Danishefsky s diene to give the dihydropyridones (Eq. 14) [25,26], The arylimines acted as the azadienes when reacted with cyclopentadiene, vinyl ethers or vinyl thioethers, providing the tet-rahydroquinolines (Eq. 15). Silyl enol ethers derived from esters, ketones, and thio-esters reacted with N-(a-aminoalkyl)benzotriazoles to give the /5-amino carbonyl compounds (Eq. 16) [27]. The diastereoselectivity was independent of the geometry of the silyl enol ethers, and favored the anti products. Nitrones, prepared in situ from aldehydes and N-substituted hydroxylamines, added to alkenes to afford isoxazoli-dines (Eq. 17) [28]. Addition of diazoesters to imines afforded CK-aziridines as the major products (Eq. 18) [29]. In all the reactions the imines could be generated in situ and the three-component coupling reactions proceeded smoothly in one pot. 

Thioethers from thiolsulfonic acid esters Replacement of C-formyl by alkylthio groups... 

Tetraethylammonium fluoride Thioethers from thiolcarbonic acid esters... 

The H-spectra of isotactic and syndiotactic polymers derived from cyclic ethers, thioethers and esters should consist only of the resonances expected for the spin systems present in the individual monomers. AB patterns are typically observed for the backbone protons in poly(a-deuterio-propylene oxide) [21], poly(a-deuterio-propylene sulfide) [22], polylactide [23], and related materials. 

Potassium hydroxide/alcohol Thioethers from thiolic acid esters s. 12, 688... 

Robertson F, Wu J. Convenient synthesis of aUyhc thioethers from phosphorothioate esters and alcohols. Org. Lett. 2010 12 2668 2671. 

Radical catalyzed additions to a,) -ethyleneboronic acid esters Thioethers from ethylene derivatives... 

Since the exocyclic sulfur is more reactive in the ambident anion than in A-4-thiazoIine-2-thione. greater nucleophilic reactivity is to be expected. Thus a large variety of thioethers were prepared in good yields starting from alkylhalides (e.g.. Scheme 38 (54, 91, 111, 166-179). lactones (54, 160), aryl halides (54, 152. 180, 181), acyl chlorides (54. 149, 182-184). halothiazoles (54, 185-190), a-haloesters (149. 152. 177. 191-194), cyanuric chloride (151). fV.N-dimethylthiocarbamoyl chloride (151, 152. 195. 196), /3-chloroethyl ester of acrylic acid (197), (3-dimethylaminoethyl chloride (152). l,4-dichloro-2-butyne (152), 1,4-dichloro-2-butene (152), and 2-chloro-propionitrile (152). A general... 

Phthalocyanine sulfonic acids, which can be used as direct cotton dyes (1), are obtained by heating the metal phthalocyanines in oleum. One to four sulfo groups can be introduced in the 4-position by varying concentration, temperature, and reaction time (103). Sulfonyl chlorides, which are important intermediates, can be prepared from chlorosulfonic acid and phthalocyanines (104). The positions of the sulfonyl chloride groups are the same as those of the sulfonic acids (103). Other derivatives, eg, chlormethylphthalocyanines (105—107), / /f-butyl (108—111), amino (112), ethers (109,110,113—116), thioethers (117,118), carboxyl acids (119—122), esters (123), cyanides (112,124—127), and nitrocompounds (126), can be synthesized. 

---