15diimide in 40 ml. of dichloromethane was added dropwise over a 3O-min. period. The resetion mixture was stirred at room temperature for 24 hr., followed by removal of the precipitated N,N'dicyclohexylm by filtration. The filtrate was concentmted by dietillation and the residue was dissolved in benzene, and p d through a column ( 1 ' X 1 0 ' ) of Florisil in benzene. The product, yelloworange crystals, m.p. 37-40', weighed 39 g. (100%) and exhibited a carbonyl absorption at 1790 em.-' in the infrared spectrum of a melted film. A d . Calcd. for CIIH&N: C, 70.58; H, 4.85; N, 7.48. Found: C, 70.85; H, 5.02; N, 7.54. N-(o-Chlozsphenyl)iso"ide. To a slurry of 45 g. (0.2 mole) of N-(o-chlorophenyl)"ic acid in 1 1. of dichlore methane, a solution of 41.2 g. (0.2 mole) of N,N'-dicycl+ hexylearbodiimide in 40 ml. of dichloromethane was added dropwise over a Sin. period. The mixture was stirred at room temperature for 24 hr., followed by filtration of the N,N'-dicyclohexylurea and distillation of the solvent under reduced pressure. The residue in benzene was passed through a column of Florid and the eluates were concentrated to yield 40 g. (97%) of yellow cry&&, m.p. 60-66". Recrystdlization of a sample from 1:1 benzenepetroleum ether @.p. 39-54') gave an analytical sample, m.p 65-67'. A d . Calcd. for CloH&tNCl: C, 57.85; H, 2.91; N, 6.75. Found: C, 58.35; H, 2.73; N, 6.58. The infrared spectrum of a liquid f i l m showed strong carbonyl absorption at 1800 an.-' I 8 -h of N-n-lnbtyliaomaleimide to N-n-hiyl-"ide. A solution of 5.0 g. (0.033 mole) of N-n-butylisomaleimide, 6.06 g. (0.06 mole) of triethylamine, and 3.6 g. (0.06 mole) of acetic acid in 100 ml. of benzene was heated a t reflux for 90 min. The solution was cooled, washed with water, dilute d u m hydroxide solution, and again with water. The bemene was removed under reduced pres-sure and the midue was distilled to yield a clear liquid, b.p. 50-55" (0.5 mm.). Vapor phase chromatographic analysis of this material showed it to be a mixture containing 40% N-n-butylisomaleimide, 59.4% N-n-butylmaleimide and 0.6% of an unknown impurity. The recovery Isomerization of N-phen&aom&imide to N -p h e n y l d eimide. A mixture of 5.0 g. (0.029 mole) of N-phenylisomaleimide, 1.0 g. (0.012 mole) of anhydrous d u m acetate and 15 ml. of acetic anhydride was heated on the steam bath for 1 hr. After the mixture had cooled to 2 5 O , it was poured into 100 ml. of water causing long, yellow needles to separate. These were collected and dried, 4.5 g. (90%) m.p. 90-91'. A mixture melting point with an authentic sample of N-phenylmaleimide was undepressed. When d u m acetate was absent in this reaction, the starting material was recovered.
