7028nm ( E 14); nmr (Dz0) 8.55 (s, 1 H), 4.18 (t, 2 H), 3.63 (singlet methyl superimposed on multiplet, 4 H), 1.7-2.8 (m, 2 H), 1.33 (d, 3 H); tlc [Iz detection, EtOH-0.1 N HCl, 2:1] one spot, Rf 0.43; tlc [Iz detection, rz-BuOH-HOAc-HzO, 4: 1 :5] one spot, Rf 0.31 after two elutions; mass spectrum (70 eV) m/e (re1 intensity) 97 (54, M+ -HCl), 96 (loo), 82 (34). Molecular Formula: Calcdfor C6H11N(Mt -HC1): 97.0891. Found: 97.0887. 1,3,3-Trimethyl-2-pyrr0lidinone-3,3-d~mer~~l-~~C (18).To 500 ml of anhydrous diethyl ether and 220 mmole (31 ml) of diisopropylamine (freshly distilled from BaO), cooled to -70", was added 131 ml (210 mmol) of rz-butyllithium (1.6 M in hexane). Then 4.95 g (50 mmol; 4.85 ml) of 1-methyl-2-pyrrolidinone was added, the solution was stirred for 15 min at -70", and 13.8 ml (220 mmol) of CH31-*4C* was added. Stirring was continued at room temperature for 16 hr, 150 ml of HzO was added, the ether layer was removed and evaporated in DUCUO, and the residue was dissolved in 100 ml of HzO. The combined aqueous solutions were continuously extracted with methylene chloride for 24 hr. Removal of the solvent and distillation of the residue at 95-97" (27 mm) gave 4.79 g (78z) of 18: nmr (CDCl8) 3.29 (t, 2 H), 2.79 (s, 3 H), 1.81 (t, 2 H), 1.04 (s, 6 H); glpc on 30% QF-1 on Chromosorb P (168'; 100 ml/min; 10 ft X 0.25 in.) one peak, 9.0 min. Arid. ,3-dimethylpyrrolidine (17). To 6 mmol of 1,3dimethyl-1-pyrrolinium chloride and 6 ml of HzO were added 35 ml of 1 N NaOH, 10 ml of HzO, 20 ml of ethanol, and 15 ml of ethyl acetoacetate. After stirring in the dark under nitrogen for 17 days, 50 ml of concentrated HCl was added. The reaction mixture was warmed on a steam bath for 5 hr, and concentrated to 5 ml in DUCUO. The residue was dissolved in 50 ml of water and made strongly alkaline with 6 N NaOH; the resulting aqueous solution was continuously extracted with methylene chloride for 4 days. Removal of the solvent gave 440 mg (47%) of 17: ir (thin film) 1730 cm-1 ( e o ) ; nmr (CDClJ 2.7-3.7 (m, 5 H), 2.69 (s, 3 H), 1.4-2.5 (m, 3 H), 2.30 (s, 3 H), 1.12 (d, 3 H); mass spectrum (70 eV) m/e (re1 intensity ) 155 (4, MT), 140 (2), 124 (28), 109 (21), 98 (100). Warming 17 with a saturated ethanolic solution of picric acid gave the picrate which was recrystallized from absolute ethanol: mp 147-151 dec; nmr (pyridine-db) 8.97 (s, 2 H), 3.Abstract: Some stable free radical analogs of histidine have been prepared which contain a nitronyl nitroxide ring system in place of the imidazole function. The esr spectra of these amino acids show magnetically nonequivalent methylene protons as shown by different hyperfine coupling constants of the P-methylene hydrogens. The 18) T. Kawamura.

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Products formed from the reaction of two chloroethylnitrosoureas in neutral aqueous solution have been identified and quantified. Mixture components recovered after a 1-h incubation period accounted for 75--85% of the starting nitrosourea. Approximately 65--85% of the reaction products were formed by an initial cleavage of the nitrosourea to the proposed intermediates 2-chloroethyl azohydroxide and an isocyanate and by subsequent hydrolytic reactions. A minor pathway, 5--10% of products, involves denitrosation of the nitrosourea with oxazoline formation. Stable isotope labeling and mass spectrometry have been used to determine the reaction sequence and product origins. Reaction product identification has been made using high-performance LC isolation and comparison with synthetic material.

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