Addition of nitroso compounds to a conjugated system

Abstract

The electronic structures of the C in carbon monoxide and the N in nitroso compds. are similar to that of S in SO2 which combines with dienes to form cyclic sulfones with a pentagonal ring. The reaction of PhNO (I) or 2-chloro-2-nitrosopropane (II) or 1-chloro-1-nitrosocyclohexane (III) with 1,3-butadiene (IV) or derivs. did not give the expected cyclic amine oxide but H2O-insol. products of a 3,4-oxidopyrrolidine structure. A mixt. of I and IV reacted so violently that diln. with C6H6 was used. A soln. of 25 g. II and 50 g. I in 350 cc. C6H6 changed from green to brown in 12 hrs. and a slight yellow cryst. ppt. formed. Removal of the solvent and steam distn. gave 63 g. 1-phenyl-3,4-oxidopyrrolidine (V), as white lustrous flakes, m. 48° (from 70% EtOH). Distn. of V with Zn gave 1-phenylpyrrole. V (16.1 g.) in 50 g. MeOH and 0.1 g. PtO2 (according to Adams) at 1000 mm. absorbed in 3 hrs. 2240 cc. H (at 0° and 760 mm.) (= theory) to give a clear yellow oil, C10H13NO, b5 105-7°, d20 1.0607, nD20 1.5535, mol. refraction 49.28. Only 0.06% active H at most was found by the Zerewitinoff method. Refluxing 20 g. V in 85 cc. HOAc and 30 g. Zn 30 min., then adding aq. NaOH soln., gave a yellow oil. Distn. gave a 1-phenylpyrroline fraction (VI), b5 115-50°, m. 101-2° (from MeOH), and 7 g. 2-acetoxypyrrolidine (VII), b5 164°. VII, distd. with H3PO4 (d. 1.71), gave a little HOAc in the distillate and then VI. VI, hydrogenated in 95% EtOH over PtO2, gave a product contg. 9.00% N (theory for 1-phenylpyrrolidine 9.53%). I (4.3 g.) and 3.4 g. CH2:CMeCMe:CH2 in 70 cc. C6H6 gave 2.5 g. 1-phenyl-3,4-dimethyl-3,4-oxidopyrrolidine, m. 39-40° (white crystals from 90% EtOH). 1-Phenylbutadiene (3.1 g.) and 2.5 g. I in 20 hrs. gave 2.5 g. 1,2-diphenyl-3,4-oxidopyrrolidine, light yellow crystals, m. 85° (from EtOH). 3,4-Oxidopyrrolidinium chloride (VIII), prepd. in 3.5-g. yield from 6 g. II (from the chlorination of Me2C:NOH), 25 cc. of 2.5 M IV in C6H6, and 3.5 cc. EtOH in 6 hrs., m. 152° (long needles from EtOH). VIII will not crystallize and yields are low unless EtOH is present in the reaction mixt. VIII can also be obtained in 35-g. yield from 68 g. III and 200 cc. of 2.3 M IV in C6H6. 3,4-Oxidopyrrolidine (IX), obtained from VIII by KOH, b20 50-2°; 3,4-oxido-1-pyrrolidinecarboxanilide, obtained from 0.42 g. IX and 0.6 g. PhNCO in 10 cc. Et2O, m. 81-2° (from EtOH). 3,4-Dimethyl-3,4-oxidopyrrolidine, obtained in 1-g. yield from 4.1 g. 2,3-CH2:CMeCMe:CH2 and a 1.2 M II in C6H6 refluxed 2 hrs., b22 83-5°; picrate m. 186° (from EtOH). [on SciFinder(R)]