Chloride acceptors

Aliphatic Alcohols and Thiols. Ahphatic alcohols on reaction with chloroformates give carbonates and hydrogen chloride. Frequendy, the reaction proceeds at room temperature without a catalyst or hydrogen chloride acceptor. However, faster reactions and better yields are obtained in the presence of alkaU metals or their hydroxides, or tertiary amines. Reactions of chloroformates with thiols yield monothiolocarbonates (14). 

Issi, J. -P., Transport properties of metal chloride acceptor graphite intercalation compounds. In Graphite Intercalation Compounds,... 

Buchanan and co-workers studied the behavior of various aromatic compounds in antimony(III) molten salts [30]. These salts can act both as mild Lewis acids and allow redox reactions to take place. The Lewis acidity of the melt can be tuned by controlling the concentration of [SbCl2]. Basic melts are formed by addition of a few mol % of a chloride donor such as KCl, whereas acidic melts are formed by addition of chloride acceptors such as AICI3 (Scheme 5.1-11). 

For the preparation of Ila and lib see (20 ). Compounds Ilc-e were prepared in reasonably good yields from aniline and 1,7-dichlorooctamethyltetrasiloxane (He), bis-(phenylamino)-dimethylsilane and 1,5-dichlorohexamethyltrisiloxane (Hd), and aniline and 1,3-dichlorotetramethyldisiloxane (He). All syntheses were carried out in DMF and in the presence of stoichiometric amounts of triethylamine as hydrogen chloride acceptor (21). 

The first known Bi cations [43] were synthesized in acidic NaAlCl4/AlCl3 melts by reaction of Bi metal and BiCl3 with AICI3 as the chloride acceptor or by direct fusion of Bi metal and BiCl3 as shown in Eqs. 1-3 ... 

The lignin modifications in solid (C) were carried out using lignins (1.0 g) mixed with corresponding amounts of hydrogen chloride acceptor and chlorophosphazenes. The reaction was carried out by heating at a temperature of 100°C, i.e., above the melting point of chlorophosphazene. The reaction mixture was poured into ice water, and then the solid product was purified as described before (9). 

Thionyl chloride is known to react with alcohols in the absence of hydrogen chloride acceptors to give reactions (2)-(7). Optimization of reactions (2), (3),... 

The need for a hydrogen chloride acceptor was shown by Bissinger and Kung [7], who found that primary and secondary sulfites decompose to the halide if hydrogen chloride is not removed (Eq. 8). The effect of hydrogen... 

Bradley and co-workers 8 advanced the attractive prenuae that certain difficultly accessible epoxides might be synthesised oonveu nil> by this approach, provided that the glycidyl ether need is a good hydrogen chloride acceptor and that the desired products can removed readily from the equilibrium mixture. 

Perhaps the most industrially feasible approach has been developed by Rich and co-workers at General Electric, a palladium-catalyzed silylative decarbonylation reaction of aromatic acid chlorides with disilanes [Eq. (35)].97 One of the silicon centers from the disilane is transferred to the arene whereas the other acts as a chloride acceptor to produce the chlorosi-... 

Polymerization also takes place when 4-halo-2.6-disubstituted phenols are oxidized with copper-amine catalysts and oxygen (5,35). In this case, stoichiometric amounts of copper salt or some other chloride acceptor (inorganic bases or strongly basic amines) are necessary since the amine complexes of copper (II) halides are not catalysts for the polymerization. Blanchard (5) has also described the polymerization of these 4-halo-phenols under conditions similar to those used by Price using certain copper (II) complexes as initiators. 

Dihydro-2//-pyrido[l,2-a]pyrimidin-2-one 675, a neutral hydrogen chloride acceptor, has been shown to give better yields in regio- and stereospecific thio- and selenolactonizations of hept-4-ynoic and hex-4-ynoic acids 683 with benzenesulfenyl and benzeneselenenyl chlorides than triethylamine [86JCS(P1)1999]. In the case of dihydropyrido[l,2-a] pyrimidinone 675, noncyclized products 685 and 686 were formed only in trace amounts. 

Here we can say that POClJ is the characteristic acid, and Cl- the characteristic base of the POCl3 solvent system. Chloride donors are therefore bases, and chloride acceptors acids in POCl3. Many covalent chlorides have the capacity both to donate and to accept Cl-, and a scale of donor/acceptor strength can be set up from studies in POCl3. 

In 1992 indole was reacted with phosphorus trichloride in petroleum ether solution in the presence of triethylamine (as hydrogen chloride acceptor) with the formation of indolyldichlorophosphite 21 (yield 35%, 145 ppm) [19, 25]. 

Unsymmetrically substituted aminoborazines resulted from the reaction of amines with B-alkylthioborazines 144>. The first optically active borazine has been obtained from the reaction of 2,4,6-trichloroborazine and (+)2-butylamine 145> using triethylamine as a hydrogen chloride acceptor. B-Monoaminoborazine, HaNsBaH NH ) and isotopically labeled derivatives thereof have been prepared by photochemical reaction from borazine and ammonia in a gas phasereaction 14fi-147>. 

The etherification can be carried out in a solvent (light petroleum ) at the boiling point of the solvent and in the presence of a hydrogen chloride acceptor (carbamide or any amine). 

The 2-oxide of 1,2,3-oxadithiolane (9) has been prepared via a two-component synthesis from 2-hydroxyethanethiol and thionyl chloride in diethyl ether using triethylamine as hydrogen chloride acceptor (75ACS(A)414). 

HFC reaction between 1,5-dichlorohexaorganocyclotetrasiloxanes and appropriate dihydroxyde-rivatives in the presence of hydrogen chloride acceptor has synthesized beadshaped cyclolinear organosiloxane polymers [27 - 31] in accordance with the general scheme as follows ... 

Arylenecyclosiloxane oligomers were synthesized in HFC reaction of 1,4-bis(dichlororganosilyl)-benzene with dihydroxydiphenylsilane and dihydroxyd-iphenylsiloxanes in 50-60% anhydrous tolu-ene solution at 1 2 ratio of the initial components both in the presence and in the absence of pyri-dine, which is hydrogen chloride acceptor. The reaction proceeded at room temperature at the final stage the reaction mixture was heated up to 100°C. The reaction scheme is as follows [87] ... 

This acid, PH(0)(0H)2, is obtained by treating PC13 or P406 with water when pure, it is a deliquescent colorless solid (mp 70.1°C, pK = 1.3). It can be oxidized to orthophosphate by various agents, but the reactions are slow and complex. The mono-, di-, and triesters can be obtained from reactions of alcohols or phenols with PC13 alone or in the presence of an organic base as hydrogen chloride acceptor. They can also be obtained directly from white phosphorus by the reaction... 

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