Amide acetals salts, quaternary

For the anionic polymerization of methacrylonitrile (MAN), many initiators have been developed, which include alkali-metal alkyls such as butyllithium [42], triphenylmethylsodium [43], phenylisopropylpotassium [43], the disodium salt of living a-methylstyrene tetramer [44], alkali-metal amides [45], alkoxides [46], and hydroxide [47], alkali metal in liquid NH3 [48], quaternary ammonium hydroxide [49], and a silyl ketene acetal coupled with nucleophilic or Lewis acidic catalysts [50]. However, only a single example of the synthesis of PMAN with narrow molecular-weight distribution can be cited, and the reported number-average molecular weights were much higher than those calculated from the stoichiometry of the butyllithium initiator [42]. 

Predictably, pyrrolidine shows a close similarity to diethylamine, although it has a higher basicity and is generally a better nucleophile than diethylamine. Consequently, it forms quaternary salts and acylation readily yields the amide. Thus, acetylation of 2-(2-pyrrolyl)pyrrolidine with acetic anhydride produces l-acetyl-2-(2-pyrrolyl)pyrrolidine (58JA6249). 

A -methoxymethyl-amines or-amides A -acetyloxymethyl-amines or -amides or A/, iV-dimethylfonnamide acetals, all react with phosphorus(III) esters in non-classical Michaelis-Arbuzov fashion. From these and similar reactions, quaternary salts of the type 186 have been isolated. The A-methylated dervative may be preformed or produced in situ in mixtures containing amide, formaldehyde and phosphite ester. The products of the reactions are A-acylated (acetyl, benzoyl, phthaloyl, pyridinecarbonyl or benzyloxycarbonyl) when derived from amides, or A,A-dialkyl derivatives from hydroxy (or methoxy)methylamines the use of Me2NCH(OMe)2 leads to dimethylaminomethyl-enebisphosphonic esters. Ivanov and coworkers have made a detailed study of the reactions which occur between phosphorus(III) amides Et2NPYZ and the substrates, RCONHOAc (Scheme 16). The reagent can attack the substrate by virtue of the nucle-... 

---