L-Cyclohexyl-2-pyrrolidinone

The influence of water as a solvent on the rate of dipolar cycloadditions has been reported [76]. Thus the rate of the 1,3-dipolar cycloaddition of 2,6-dichloroben-zonitrile N-oxide with 2,5-dimethyl-p-benzoquinone in an ethanol/water mixture (60 40) is 14-fold that in chloroform [76b]. Furthermore the use of aqueous solvent facilitates the workup procedure owing to the low solubility of the cycloadduct [76b]. In water-rich solutions, acceleration should be even more important. Thus in water containing 1 mol% of l-cyclohexyl-2-pyrrolidinone an unprecedented increase in the rate of the 1,3-dipolar cycloaddition of phenyl azide to norbornene by a factor of 53 (relative to hexane) is observed [77]. Likewise, the 1,3-dipolar cycloaddition of C,Ar-diphenylnitrone with methyl acrylate is considerably faster in water than in benzene [78]. Similarly, azomethine ylides generated from sarcosine and aqueous formaldehyde can be trapped by dipola-rophiles such as N-ethylmaleimide to provide pyrrolidines in excellent yields... 

Beilstein Handbook Reference) BRN 0121832 CHP l-Cyclohexyl-2-pyrrolidinone N-Cyciohexylpyrrolidinone N-Cyclohexylpyrrolidone N-Cyclohexyl-2-pyrrolidone EINECS 229-919-7 2-Pyrrolidinone, 1-cyclohexyl-. Solvent, used as a reaction intermediate, textile auxiliary, cosmetic ingredient. Liquid bp7 n 154° d = 1.0070 LDso (rat orl) = 370 mg/kg. ISP. 

Kinetic data regarding the 1,3-dipolar cycloaddition of phenyl azide with norbornene in various solvents to give triazoline 98 were reported by Engeberts (Table 5.8). A high reaction rate enhancement (a factor of 53 relative to n-hexane) was observed when the reaction was performed in water containing 1% of l-cyclohexyl-2-pyrrolidinone (NCP). 

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