444 Unusual Course of Reaction of Buta-1,3-diene- 1,4-diylbis(triphenylphosphonium Chloride) with Phenylhydrazine M. Zh. Ovakimyan, M. L. Movsisyan, G. A. Gasparyan, and M. G. Indzhikyan Institute of Organic Chemistry, National Academy of Sciences of Armenia, ul. Z. Kanakertsy 167a, Yerevan, 375091 Armenia e-mail: ioc_phos@mail.ru Received July 20, 2010 LETTERS TO THE EDITOR ISSN 1070-3632, Russian Journal of General Chemistry, 2011, Vol. 81, No. 2, pp. 444–446. © Pleiades Publishing, Ltd., 2011. Original Russian Text © M.Zh. Ovakimyan, M.L. Movsisyan, G.A. Gasparyan, M.G. Indzhikyan, 2011, published in Zhurnal Obshchei Khimii, 2011, Vol. 81, No. 2, pp. 346–348. Previously we have found that triphenyl- and tri- butyl-2-phenylhydrazinoethylphosphonium salts when heated in ethanol or DMF are dehydrated to form phenylhydrazones of the corresponding phosphonium acetic aldehydes in high yields [1]. The same reaction occurred in the case of triphenyl- and tributyl- phosphonium salts with 4-N-phenylhydrazino-3-chloro- but-2-enyl group [2]. Based on the results of these studies we suggested that this reaction had a cyclic nature including the shift of a lone electron pair to the onium phosphorus atom and the hydride ion expulsion from the neighboring sp 3 -carbon atom [3]. We found that buta-1,3-diene-1,4-diylbis- (triphenylphosphonium chloride) I at reflux with 2 mol of phenylhydrazine in chloroform formed 2-phenyl- hydrazonobutane-1,4-diylbis(triphosphonium chloride) II in 85% yield. Yield of compound II decreased to 51% when the starting reagents were used in the equimolar ratio. The reaction was accompanied in both cases with the formation of phenylhydrazine hydro- chloride in high amounts. The latter was established to form by the reaction of phenylhydrazine with chloroform. As expected, the reaction of salt I with equimolr amount of phenylhydrazine in acetonitrile affords compound II almost in the quantitative yield. Probably the formation of salt II occurs through initial addition of phenylhydrazine at one of multiple bonds of salt I to give intermediate III followed by hydro- genation of the multiple bond involving the transfer of a hydride ion by the cyclic mechanism: DOI: 10.1134/S1070363211020344 Cl - Ph 3 P PPh 3 + + Cl - PhNHNH 2 Cl - Ph 3 P PPh 3 + + Cl - H N H PhNH Cl - Ph 3 P PPh 3 + + Cl - II NNHPh I III Cl - Ph 3 P PPh 3 + + Cl - 3 PhNHNH 2 IV Ph 3 P NNHPh + V + II + Ph 3 P=NHNHPh + Ph 3 PO + VI Cl - Compound II was found to form also from 2- butene-1,4-diylbis(triphenylphosphonium chloride) IV via the reaction with threefold excess of phenyl- hydrazine in chloroform, but its yield was 7% only. At the same time among the reaction products were also triphenyl(4-phenylhydrazonobut-2-enyl)phosphonium chloride V (46%), triphenylphosphine oxide (34%), and N-phenyltriphenylphosphine imine hydrochloride VI (19%), identified by the 1 Н NMR and elemental analysis data, and phenylhydrazine hydrochloride.