Anionic pyrrolidinone

Commercial narrow standards [such as poly(ethylene glycol) (pEG), polystyrene sulfonate, pAA, poly w-vinyl pyrrolidinone, dextrans] are available from American Polymer Standards Corporation, Polymer Laboratories, Polymer Standards Service USA, Toyo Soda, and others. While these standards are often not as narrow as pSty or pMMA that has been anionically polymerized, they are acceptable for narrow standard calibrations. 

The relative importance of the hafide anion - HO - Cell interactions can be inferred from application of the Taft-Kamlet-Abboud equation to the UV-Vis absorbance data of solvatochromic probes, dissolved in cellulose solutions in different solvent systems, including LiCl/DMAc and LiCl/N-methyl-2-pyrrolidinone [96]. According to this equation, the microscopic polarity measured by the indicator, Ej (indicator), in kcalmol is correlated with the properties of the solvents by Eq. 1 ... 

In THF at -20°C the N-trimethylsilylated 2-pyrrolidinone 388 is converted by LDA into the a-anion which, on reaction with 1949 and subsequent acidification with AcOH, gives 43% 3-hydroxy-2-pyrrolidinone 1962 [150]. Lithium enolates of ketones such as camphor react with BTSP 1949 to give >95% of a mixture of exo-and mdo-2-hydroxycamphor [151]. Lithiated methyl heterocycles such as lithiated 2-methylpyridine 1963 are converted into mixtures of the 0-SiMe3 1964 and C-SiMe3 1965 compounds and C-methylated compounds such 1966 [152]. 2-Lithioto-luene 1967 is oxidized by 1949 into 1968 [140, 145] (Scheme 12.42). 

Proliferous Polymerization. Eady attempts to polymerize VP anionically resulted in proliferous or "popcorn" polymerization (48). This was found to be a special form of free-radical addition polymerization, and not an example of anionic polymerization, as originally thought. VP contains a relatively acidic proton alpha to the pyrrolidinone carbonyl. In the presence of strong base such as sodium hydroxide, VP forms cross-linkers in situ, probably by the following mechanism ... 

More recently, a tandem Heck/allylic substitution cascade was used as a route toward various lactams. The reaction of 631a,b with 2-isopropenyl bromide in the presence of Pd(OAc)2 and (o-tolyl)3P gave the Heck adduct 632 that reacted further with H-Pd-Br to give the 71-allylpalladium complex 633. Intramolecular attack of the amide anion on the 7i-allyl complex followed by reductive elimination of Pd(0) afforded 634a,b in 77 and 75% yield, respectively (03OL259). Other vinyl bromides were also examined and found to give substituted pyrrolidinones and piperidones in moderate to good yields (50-82%). 

P-Propiolactam, 3,3- and 4,4-disubstituted propiolactams can be polymerized to form unsubstituted and substituted nylon-3. Anionic polymerization was initiated by nylon-6,6 and carried out at 200-250°C. Polymers of high molecular weights were obtained from 3,3-disubstituted lactams. However, solution polymerization at 0-20°C with 25% monomer concentration in a solvent such as dimethyl sulfoxide with strongly basic activators such as potassium pyrrolidinonate also gave high molecular weights. Poly(4,4-dimethylpropiolactam) with Tjinh of 4.5 dl/g and Mw of 50,000 was reported [70]. 

Pyrrolidinone is polymerized by anionic polymerization to form polypyrrolidinone or nylon-4 [71]. The polymerization process gives a polymer of high molecular weight in 80-85% yields at temperatures below 60°C. The polymer forms a fine dispersion in hydrocarbon. It can be extracted by water to remove unreacted monomer and residual catalyst. The dispersion is suitable for dry spinning since the polymer can be readily dissolved at elevated temperatures. 

The yields of these unsymmetrical diarylamides depend on the substrate-nucleophQe pair used. For the same product and thus for the same radical anion (Ar = Ph and Ar = 9-phenanthryl, or vice versa), the best yield is obtained with the least stabilized anion, where a less significant loss in K energy occurs. Lactam nucleophiles, such as the anion of l-methyl-2-pyrrolidinone, react with aryl halides under irradiation. When the reaction of 1-iodonaphthalene with the aforementioned anion is quenched with methyl iodide, the 3-(l-naphthyl)-3-methyl- substituted compound is obtained ... 

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