2-Pyrrolidone ring

N-Condensed 3-pyrrolidone ring synthesis Michael addition combined with Dieckmann cyclization Subsequent -decarbalkoxylation... 

Aso et al. (40) examined the molecular mobility of sucrose and polyvinylpyrrolidone in 1 1 lyophilized mixtures by measuring the spin-lattice relaxation times (7)) of individual carbon atoms by NMR for systems containing residual moisture at varying levels. 7) of the pyrrolidone ring carbon increased with residual moisture for lyophilized PVP alone. However, the mobility of these carbons did not increase with residual moisture when PYP was colyophilized with sucrose. Similarly, the mobility of sucrose did not increase with water activity as much in sucrose/PVP mixtures as much as in sucrose alone. Inhibition of sucrose crystallization by PVP in the presence of water appears to be linked to the effect of PVP on the molecular mobility of sucrose. 

We consider that all of the dolastatins will prove to be of cyanobacterial or other dietary origin. There are some important biosynthetic signatures, for exanqile, which suggest that dolastatin 15 (2) (Figure 1) is most probably derived from L majuscula. These signatures include the presence of the N,N-dimethylvaline residue, a valine-N-methylvaline-proline sequence also found in the microcolins (27, 28) (Figure 7) and the presence of a pyrrolidone ring presumably derived from condensation of phenylalanine and acetate. A... 

All members of a series of oxotremorine analog (184a-e), in which the pyrrolidone ring iscontracted to a j3-lactam moiety (217), demonstrated uniformly weak cholinergic effects. 

Conversion of the pyrrolidone ring of oxotremorine and some congeners into an imid-azolidone ring (186) produces compounds (generally of low potency) with a variety of effects at muscarinic receptors (218). 

Figure 2.47 Structure of the protein collagen. (A) Space-fiiling model of collagen. Each strand is sho wn in a different color. (B) Cross section of a model of collagen. Each strand is hydrogen bonded to the other two strands. The u carbon atom of a glycine residue is labeled G. Every third residue must be glycine because there is no space in the center of the helix. Notice that the pyrrolidone rings are on the outside.

The oxazoline 184 provides an attractive approach to lactacystin as it is a protected form of 3-hydroxyleucine. The other half of the molecule was made in the LeukoSite synthesis by a very different method the alkylation of an Evans chiral auxiliary. This was chosen partly because they wished to vary the alkyl group on the pyrrolidone ring and we use the propyl compound as example. The phenylalanine derived oxazolidinone 193 (chapter 27) was acylated and then the titanium enolate of 194 was alkylated to give 195 with very high selectivity and the chiral auxiliary removed to give the simple acid 196. 

The photoinduced polymerization of 3-alkylated-2-pyrrolidones has been found to increase with substitution on the pyrrolidone ring system, while vinylidene fluoride (VDF) in the presence of hydrogen peroxide gives telechelic PVDF through the formation of hydroxyl radicals, which can react with the fluorine sites to give carboxyl end groups. The photoinduced polymerization of... 

The leaves of Cynometra anata have yielded the structurally interesting new alkaloids anatanine (5), cynometrine (6 R = H), and cynodine (6 R = COPh), whose structures were deduced on the basis of spectral and chemical evidence. The stereochemistry embodied in the 2-pyrrolidone ring, and the geometry about the double bond in (5), remain to be elucidated. 

Ring closures with ninhydrin 4,5-Dihydroxy-2-pyrrolidone ring from carboxylic acid amides... 

The pyrrolidone ring can then be built onto the side chain to yield the selective herbicide fluorochloridone. 

To preserve beer colloidal stability, brewers usually remove haze-active materials [34]. To get rid of haze-active proteins, precipitation with tannic acid, hydrolysis with papain and adsorption to bentonite [35] or silica gel [36, 37] are very effective, but unfortunately in some cases, such procedures also remove foam proteins. To remove haze-active polyphenols, the most usual way is adsorption to polyvinylpolypyrrolidone-PVPP. Because of the structural analogy between these compounds and proline [38], pyrrolidone rings bind polymerized flavanoids through hydrogen and ionic bonds. 

These products are characterized by superior wetting (especially LP-100), surface tension reduction and solvency. The intrinsic multifunctionality often enables the SURFADONE nonionios to replace several additive surfactants. The ability of the pyrrolidone ring to complex polar materials allows SURFADONE LP surfactants to be used to alter the solubility, vapor pressure or irritation potential of various classes of materials such as phenolics. 

A mixture of 2-bromomethylbenzoyl bromide, N,N-dimethylthiourea, and Na-carbonate refluxed 24 hrs. in acetone -> 3-dimethylamino-2,4-benzothiazepin-5-one. Y 90%. F. e. and method, also 2-pyrrolidone ring formation, s. D.N. Rein-houdt, R. 92, 20 (1973). 

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