Sulfonic acids, addition with ethers

Hydroxybutylation of hydroquinones. Reaction of hydroquinoncs with 1 in the presence of D-camphor-lO-sulfonic acid gives monotetrafuryl ethers (2), which rearrange to 2-tetrahydrofurylhydroquinones (3) in the presence of additional amounts of the acid... 

Amino-5-phenylthiomethoxyacetanilide in methanol solution is heated with N,N -bis-meth-oxycarbonyl-isothiourea-S-methyl ether with the addition of a catalytic amount of p-toluene-sulfonic acid for three hours with stirring under reflux. The mixture is then filtered hot and after cooling the febantel product crystallizes out. It is filtered off, rinsed with ether and dried under high vacuum to give the final product, melting at 129°C to 130°C. 

A. 3,3-Pmtamethylenediaziridine. A solution of 147 g. (1.5 moles) of cyclohexanone in 400 ml. of 15iV aqueous ammonia (6.0 moles) in a 1-1. beaker is stirred mechanically and cooled to 0° with an ice-salt mixture. Maintaining the temperature of the solution between 0° and - -10°, 124 g. (1.0 mole) of 90% hy-droxylamine-O-sulfonic acid (Note 1) is added in portions of about 1 g. The addition requires about 1 hour, and the mixture is stirred for mother hour at 0° and allowed to stand overnight at —15° in a refrigerator. The precipitated crystalline cake is filtered and pressed tight with a glass stopper. The solid is washed with 50-ml. portions of ice-cold ether, toluene, and finally ether. There is obtained 110-115 g. of product which is 70-90% pure (Notes 2 and 3). The product is divided into two portions, each of which is boiled briefly with a 50-ml. portion of toluene the solutions are decanted from small salt residues and cooled to 0° for 2 hours. The precipitates are filtered with suction and washed with 50 ml. of ice-cold petroleum ether. The combined yield of 3,3-pentamethylenediaziridine is 68-78 g. (61-70%), m.p. 104-107°. The purity is 96-100% (Note 4). 

Chlorides of sulfonic acids can be reduced either partially to sulfinic acids, or completely to thiols. Both reductions are accomplished in high yields with lithium aluminum hydride. An inverse addition technique at a temperature of —20° is used for the preparation of sulfinic acids, while the preparation of thiols is carried out at the boiling point of ether [69S]. 

S. Phenyl vinyl eulfone. In a 250-mL, three-necked, round-bottomed flask fitted with a magnetic stirrer, condenser, addition funnel, and thermometer is placed 19.7 g (0.145 mol) of phenyl vinyl sulfide dissolved in 70 mL of glacial acetic acid. Hydrogen peroxide (30%, 56 mL, 0.5 mol) is added slowly at such a rate to maintain a reaction temperature of 70°C (Note 7). The reaction mixture is heated at reflux for 20 min, cooled, and treated with ether (150 mL) and water (200 mL). The organic phase is separated, washed with water (50 mL) and brine (50 mL), and concentrated at 70°C/0.3 mm for 3 hr, to afford 18-19 g (74-78%) of phenyl vinyl sulfone as a colorless... 

The selenosulfonates (26) comprise another class of selenenyl pseudohalides. They are stable, crystalline compounds available from the reaction of selenenyl halides with sulftnate salts (Scheme 10) or more conveniently from the oxidation of either sulfonohydrazides (ArS02NHNH2) or sulftnic acids (ArS02H) with benzeneseleninic acid (27) (equations 21 and 22). Selenosulfonates add to alkenes via an electrophilic mechanism catalyzed by boron trifluoride etherate, or via a radical mechanism initiated thermally or photolytically. The two reaction modes produce complementary regioselectivity, but only the electrophilic processes are stereospecific (anti). Similar radical additions to acetylenes and allenes have been reported, with the regio- and stereochemistry as shown in Scheme 11. When these selenosulfonation reactions are used in conjunction with subsequent selenoxide eliminations or [2,3] sigmatropic rearrangements, they provide access to a variety of unsaturated sulfone products. 

Recent attempts to prepare 26 by RAFT, however, failed [153]. Double hydrophilic block copolymers of NIPAM and 23e [154], as well as of N,N-diethylacrylamide and 23b [155], were prepared with the CTA benzyl dithiobenzoate, and exhibit LCST and UCST behavior in water. The new polymer 51 is also part of amphiphiUc di- and triblock copolymers [152]. Diblock copolymers with poly(ethylene glycol) methyl ether acrylate, dimethylacry-lamide, or 4-vinylstyrene sulfonate are macrosurfactants with a switch-able hydrophobic block. Triblock copolymers containing additionally 4-vinylbenzoic acid differ in the nature of the hydrophilic part [152]. Near-monodisperse block copolymers of N,N-dimethacrylamide and 49a were synthesized in different ways via macro-CTAs of both monomers as the first step. Such sulfobetaine block polymers form aggregates in pure water but are molecularly dissolved after addition of salt [152,156,157]. 

Various sulfuric and phosphoric acid esters have sometimes been used instead of alcohols as starting materials for the preparation of nitriles. Of more general importance are sulfonates, particularly from methane- or p-toluene-sulfonic acid, which react in an 5N2-type substitution with cyanide ions. The most common starting materials are, as described in Section 1.8.1.2.1, alkyl halides, and if their preparation creates problems, the use of sulfonates may be advantageous. The addition of crown ethers or the... 

The reactive distillation operation is obviously not limited to zeolite catalysts. It can also be carried out with homogeneous acids such as sulfuric acid or p-toluene-sulfonic acid. Since they lack shape selectivity, these catalysts first convert phenyl-ethanol to the corresponding ether and only then to styrene. Hence, the reaction proceeds in a solution of heavy products that have accumulated over time. Additives have been developed to control the oligomerization reactions and keep the liquid viscosity at a workable level [35]. The heavy liquid medium needs to be bled. Its contamination with strong acid makes its disposal costly, however. 

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