Bull. Soc. Chim. Belg. vol. 101 / n'3 / EUROPEAN SECTION 1992 0037-9646 / 92 / $ 2.00 + 0.00 o 1992 Comité van Beheer van het Bulletin v.z.w. HALIDES NOVEL SYNTHESES OF HETEROCYCLES WITH N-(1-HALOALKYL)AZTN|UM PART 1. PREPARATION OF IMIDAZOLIDINES l I ,l J.-J. Vanden Eynde, A. Mayence and A. Maquestiau Organic Chemistry Laboratory, University of Mons-Hainaut, 8-7000 Mons (Belgium) and E. Anders lnstitut fLrr Organische Chemie der Universitât Erlangen-NÛrnberg, Henkestrqpe 42, DA520 Erlangen (Germany) Received :24110/1991 - Accepted :2010'tfiæ2 ABSTRÀCT: N-(1-Chloroalkyl)pyridinim chlorides, prepared from thionyl chlorj.de, pyridine, and an aldehyde, readily react with N,N'-disubstituted 1.,2-ethanedianine to yield inidazolidines under mild and neutral conditions, INTRODUCTION Reaction between a thionyl halide, pyridine, and an aldehyde is known to produce N-(1-haloalkyl)pyridinium halides (cfr. Figure 1) in good yields.'. Such salts represent an activated form of the starting aldehydes in which both the halide and the pyridinium moiety can be exchanged. For example tbey react with primary anines to afford imines3,n and with secondary arnines to yield 1,1-diamines.3 To extend those results we now report on the chemical behaviour of N-(1-chloroalkyl)pyridinium chlorides towards diamines. RESULTS Anders and al.' observed that N-[bromo(4-nethylphenyl)methy]lpyridinun bromide reacts with 1,2-ethanediamine, in dichloromethane at room tenperature, to yierd the corresponding diinine. we confirmed that result from N-(chtoro- phenylmethyl)pyridinium chloride 1a even in di-Iute solutions and we found that best yields of 2 (Figure 2) are obtained when one equivalent of salt is allowed to react with 2.5 equivalents of the diamine. Hydrochloric acid, evolved during the reaction, is trapped by the diamine to yield its monohydrochloride. Free pyridine is recovered at the end of the procedure as indicated by the analysis of the 1H nmr spectrun of the crude reaction medium. Similar results were obtained in the reaction involving 1,3-propaned.iamine that afforded the diimine 3 (Figure 2). soct,+Q**""o cH,clz> ô Y* I CH RCt 1a-h R la CuHu- 1b 4-(CH3)-C6H4- cl - lc z-cr-c.H4- 1d 4-(OCH3)-C6H4- 1e C,H"- 1f c.H,- 1-g (CH3)r-C- th 2-furyl- Figure 1. -233-