Dimethyl-2-pyrrolidone

To a solution of 148 g. (0.845 mole) of methyl 7-methyl-7-nitrovalerate (p. 86) in 500 ml. of commercial absolute ethanol (total volume about 632 ml.) in a 2.5-1. rocking high-pressure bomb is added 12.5-25.0 g. (Note 1) of W-5 2 Raney nickel catalyst (Note 2), previously rinsed with absolute ethanol. The bomb head and fittings are placed in position, including a thermocouple attached to a semi-automatic heating control (Micromax). Hydrogen is introduced into the bomb until the pressure reaches 1000 lb. per sq. in. (Note 3). 

The bomb is rocked and the temperature of the solution is raised carefully to 55° during the course of 0.5-1.0 hour (Note 4). The hydrogen uptake begins at 40-51°, and during the reaction period the temperature is held at 55-60°. The rate of pressure drop is 50-100 lb. per sq. in. each 15 minutes. The rocking of the bomb is continued, and the temperature is maintained at 60° until the pressure reading is constant for 1 hour, in order to ensure completion of the reaction. 

After the bomb has been cooled the contents are removed and allowed to stand until the catalyst has settled (Note 5). The mixture is filtered, and the filtrate is transferred to a Claisen flask placed in an oil bath. The solvent is removed by distillation at atmospheric pressure, and the oil-bath temperature is raised to 200°. After temporary cooling, the residue in the flask is distilled under reduced pressure. The 5,5-dimethyl-2-pyrrolidone boils at 126.5-128.5°/12 mm. and solidifies in the receiver. The yield is 84-92 g. (88-96%) m.p. 42-43° (Note 6). 

It is unnecessary and may in fact be dangerous to use a larger amount of catalyst. 

The checkers have found that commercial grade Raney nickel (Gilman Paint and Varnish Company) is a satisfactory substitute for W-5 catalyst. The yields obtained with the two catalysts are identical, but the hydrogenation requires 2-3 hours with commercial catalyst compared with 1-1.5 hours for W-5 catalyst. 

Submitted by Robert L. Frank, William R. Schmitz, and Blossom Zeidman. 

Staley Manufacturing Company s Grade A levulinic acid was used. 

The course of the reaction may be followed by the drop in hydrogen pressure, the decrease depending upon the size of the bomb employed. 

Because of its pyrophoric nature, the nickel catalyst should not be allowed to dry on the filter. A convenient alternative procedure for removing catalyst is to centrifuge the reaction mixture. 

The product of some runs has a light yellow tint, but the color appears to cause no complications in subsequent reactions of the material. 

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Reduction of 5,5-dimethyl-2-pyrrolidone with 3 mol of lithium aluminum hydride by refluxing for 8 hours in tetrahydrofuran gave 2,2-dimethylpyrrol-idine in 67-79% yields [1123]. Reduction of e-caprolactam was accomplished by heating with sodium bis(2-methoxyethoxy)aluminum hydride [544], by successive treatment with triethyloxonium fiuoroborate and sodium borohydride [1121], and by refluxing with borane-d ras. )a.y sulfide complex [1064]. 

Dimethyl-2-pyrrolidone has been prepared by the hydrolysis of 5-imino-2,2-dimcthylpyrrolidinc in the presence of Raney... 

Dimethyl-l,2-pyrone, 32, 78 5,5-Dimethyl-2-pyrrolidone, 32, 59 Dimethyl sulfate, 31, 72, 91 Dimethyl cz, v-A4-tetrahydrophthalate,... 

A 3-1. three-necked round-bottomed flask is placed on a steam bath and fitted with a mercury-sealed Hershberg stirrer, a dropping funnel, and an efficient reflux condenser topped with a tube containing soda lime and calcium chloride. In this flask are placed 38 g. (1 mole) of pulverized lithium aluminum hydride (Note 1) and 400 ml. of dry tetrahydrofuran (Note 2). The mixture is heated under reflux with stirring for 15 minutes or until most of the lithium aluminum hydride has dissolved. A solution of 90.5 g. (0.8 mole) of 5,5-dimethyl-2-pyrrolidone 2 in 200 ml. of diy tetrahydrofuran (Note 2) is added slowly at such a rate that the solvent refluxes gently without external heating. When the addition is complete and the initial reaction subsides, the mixture is stirred and heated at gentle reflux for 8 hours. 

Methylene-5,5-dimethyl-2-pyrrolidone 8.2 Solution polymerization in DMSO with 179... 

For preparation of an intermediate required for the synthesis of 5,5-dimethyl-pyrrolidone, Moffett used absolute ethanol as solvent and the W-5 catalyst. 

Weaker polar monomers like, vinylacetate, N-vinyl pyrrolidone, fV-vinyl caprolactam or MiV-dimethyl acrylamide may be used at levels as high as 30-40% of the total monomers. Combinations of polar monomers [65-67] can also be used to formulate acrylic PSAs with a good balance of properties. 

Alcoholic potassium hydroxide or sodium hydroxide are normally used to convert the halohydrins to oxiranes. Other bases have also been employed to effect ring closure in the presence of labile functional groups such as a-ketols, e.g., potassium acetate in ethanol, potassium acetate in acetone or potassium carbonate in methanol.However, weaker bases can lead to solvolytic side reactions. Ring closure under neutral conditions employing potassiunT fluoride in dimethyl sulfoxide, dimethylformamide or A-methyl-pyrrolidone has been reported in the patent literature. 

The enolate of dimethyl trifluoromethylmalonate, formed by the action of cesium fluonde [II9] or of an electrolytically generated pyrrolidone anion [120], can be alkylated with methyl iodide (equation 103)... 

Carbanions of active methylene compounds also react with aziridine-2-car-boxylic esters to give ring-opened products [129]. The ring-opened intermediates usually cyclize spontaneously to pyrrolidones. Treatment of 190 (Scheme 3.70) with the sodium enolate of dimethyl malonate 191, for example, afforded pyrroli-done 192 in 15% isolated yield, together with 30% of the debenzoylated product 193. 

The reaction of /V,/V-dimethylacetamide dimethyl acetal and dimethyl malonate at ambient temperature for 1 week, and that of l-benzyl-2-pyrrolidone dimethyl acetal and dimethyl malonate in boiling methanol for 36 hr, gave N, N-disubstituted aminomethylenemalonates (332) in 60% and 87% yields, respectively (69JA6683). 

R,5S)-(-)-6,6-Dimethyl-3-oxabicyclo[3.1,0]hexan-2-one. Highly tnantioselective Intramolecular Cyclopropanation Catalyzed by Dirhodium(ll) Tetrakis[methyl 2-pyrrolidone-5(R)-carboxylate],... 

Alditols are insoluble in nonpolar organic media but are soluble in polar solvents such as pyridine, dimethyl sulfoxide, 2-pyrrolidone, and acetone. Unfortunately, the latter solvents cause a large reduction in enzyme activity. A simple and versatile... 

The reaction of l-methyl-2-(methylmercapto)-2-pyrroline (282) with DMAD is known to give a dihydroazepine derivative (283) (Eq. (38)1. The recent report of the reaction of 1-methyl-2-pyrrolidone dimethyl-acetal (284) with DMAD to give products like 286, 287, 288, and 289 may be interpreted as essentially the reaction of the enamine system (285) (Scheme 45). Other examples of the reaction of enamines include the reaction of the pyrrolidinopentenone (290) to give the phthalate (293)... 

Investigation of template poly condensation kinetics has only been studied within a very narrow scope. Polymerization of dimethyl tartrate with hexamethylene diamine was found to be enhanced by using as a template poly(vinyl pyrrolidone), poly(2-vinyl pyridine), or polysaccharides and poly(vinyl alcohol), poly(4-vinyl pyridine). In this case, the template can be treated as a catalyst. No information exists on the influence of the template on the order of reaction. The increase in molecular weight of the polymerization product by the template can be induced by a shift of equilibrium or by an increase in the reaction rate. A similar increase in the reaction rate was observed when poly(4-vi-nyl pyridine) was used in the synthesis of poly(terephtalamides) activated by triphenyl phosphite.The authors suggested that a high molecular weight template was involved in the increase of the local concentration of the substrate (terephthalic acid) by adsorption and activation via N-phosphonium salt of poly(4- vinyl pyridine). 

For (a), hydroxypropyl cellulose (HPC) (6-8), poly(vinyl pyrrolidone) (PVP) (9,10), poly(acrylic acid) (PAA) (9), and poly(dimethyl siloxane) (PDMS) (11) are usually employed. Ober et al. reported that the copolymers of isobutylene/isoprene and various methacrylates, which have weak polarity, are appropriate stabilizers for... 

To a stirred flask containing a suspension of 4.8 gm (0.2 mole) of sodium hydride in 50 ml of THF under a nitrogen atmosphere is added dropwise 13.3 gm (0.2 mole) of cyclopentadiene. In a separate flask are mixed 19.8 gm (0.2 mole) of A-methyl-2-pyrrolidone and 25.2 gm (0.2 mole) of dimethyl sulfate. (NOTE Separately A-methyl-2-pyrrolidone and dimethyl sulfate should be anhydrous and should be purified by distillation before reacting with each other to form the complex.) The latter mixture is heated for 20 min on a steam bath, cooled, and then added dropwise to the cyclopentadienylsodium solution at —5°C. After the addition, the reaction mixture is stirred for 2 hr, filtered, the filtrate concentrated, and the residue is obtained as a brown oil. On cooling, the brown oil solidifies and is recrystallized from cyclohexane to afford pale-yellow needles weighing 14.0 gm (50%), m.p. 100°-101°C. 

Sometimes, mixture of solvents with water have been employed, probably with the aim of improving the phase transfer. These mixtures include ethanol/watcr,107 acetic acid/water.42-108 dioxane/water,109 diethyl ether/water, 10111 and tetrahydrofuran/water.46 Other solvent mixtures, e.g, ethanol/ dioxane,112 ethanol/diethyl ether, 3 diethyl ether. hexane,113 and dimethyl sulfoxidc/l-methyl-2-pyrrolidone,102 have been used in selected cases, with no given reason. 

The principal product of prolonged irradiation of the oxaziridine (175), formed from 3,5,5-trimethyl-l-pyrroline 1-oxide, is 3,5,5-trimethyl-2-pyrrolidone (176). In this instance, the 1,2-shift of a hydrogen atom, possible in pyrrolidines not containing an alkyl substituent on C-2, is preferable to pyrrolidine ring cleavage. A similar effect is observed in the photolysis of 5,5-dimethyl-l-pyrroline 1-oxide.147... 

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