Monocyclic and Fused 4-Imino(4-Oxo)-1,3,2-Diazaphospholanes and - Phosphorinanes. Synthesis and Some Properties

Abstract

In contrast to the great variety of well known phosphorus heterocycles with exocyclic C=O double bond the number of ones containing exocyclic C=N bond is unusually modest. We elaborated the convenient method of preparation of various N,P,N-heterocycles with exocyclic C=N bond (1–4) from the readily available corresponding amino acid amidines and appropriated dichlorides or diamides of phosphorus (III) acids. Rings' 1–3 with P(III) are easily converted into (thio)phosphoryl derivatives, while the direct phosphorylation of amino amidines by RP(Y)Cl₂ is unusually ineffective. Tricycles 4 - derivatives of 2-(2-amino pheny1)imidazoline - mainly exist in the more conjugated hydrophosphazo tautomeric form 4b (>90 %).     

Binding of 1,5-bis(p-sulfonatophenyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane with tetra(methyl viologen) calix[4]resorcinol

Binding of an amphiphilic dianion 1,5-bis(p-sulfonatophenyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane (APCO^2?) with an amphiphilic octacation tetra(methyl viologen) calix[4]resorcinol (MVCA⁸⁺) in media containing different amounts of water and DMSO using NaClO₄ or NaCl as supporting electrolytes was shown for the first time by cyclic voltammetry and spectrophotometry. The stoichiometry of the complex depends on the MVCA⁸⁺: APCO^2? ratio, medium, and supporting electrolyte. A 1: 1 charge-transfer complex is mainly formed (λ_max = 480 nm) in 30% DMSO at a ratio of the compounds of 1: 1. A similar 1: 1 complex of APCO^2? with a model compound methyl viologen MV²⁺ (λ_max = 482 nm) is formed under these conditions. A donor-acceptor interaction occurs between the acceptor viologen units and nitrogen-centered electron-donating fragments of the APCO^2? dianion. An increase in the content of APCO^2? in the solution leads to an additional binding of one (30 vol.% DMSO, water, NaClO₄) or two (30 vol.% DMSO, water, NaCl) particles of APCO^2? with the hydrophobic fragments of MVCA⁸⁺. The complexes aggregate to form insoluble precipitates in aqueous and water-DMSO media. A selective reversible electroswitching from the bound to free state of one of the three bound APCO^2? particles was performed when reducing MVCA⁸⁺ to MVCA^4·+ in a 30 vol.% DMSO/NaCl medium.     

Efficient stereoselective alkenylation through a homolytic domino reaction involving a 1,5 sulfur-to-carbon translocation

An effective method for cis-stereoselective attachment of functionalized alkenyl appendages to sp3 carbon is reported. This method is based on a free-radical process, involving a sequence of addition-elimination steps, resulting in alkenyl group transposition from divalent sulfur to a prochiral carbon radical. Absolute stereoselectivity is secured since the new carbon-carbon bond is formed in a ring-closure reaction leading to a bridged bicyclic carbon-centered radical intermediate. The latter undergoes beta-scission of the C-S bond, leaving the alkenyl side chain in its predetermined position while releasing a thiyl radical. This thiyl radical is trapped by tri-n-butylstyryltin, affording a (styrylsulfanyl)methyl side chain and a tri-n-butyltin radical that continues the chain. When 2-(alkenylsulfanyl)methyl-4-bromo(or iodo)pyrrolidines were used as starting materials 2,4-cis-disubstituted 4-alkenyl-2-(styrylsulfanyl)methylpyrrolidines were obtained as products (70-90% yield). Tri-n-butylstyryltin was used rather then the more common n-Bu3SnH as tin radicals sources because the latter led predominantly to bridged bicyclic 3-thia-6-azabicyclo[3.2.1]octanes (up to 77% yield). An additional advantage of using tri-n-butylstyryltin derives from the discovery that the resulting styrylsulfide functionality is an excellent synthetic equivalent to the formyl group. Thus, using a Pummerer-type oxidative desulfurization, 4-cis-alkenyl-proline aldehydes were obtained.     

Aminoamidines

Reactions ofN-aryl- andN-methyl-amidines and -amides of -amino acids with RPCl₂ afford 4-aryl(methyl)imino and 4-oxo-1,3,2-diazaphospholanes. 4-Phenylimino-1,3,2-diazaphosphorinane was obtained in a similar way by the interaction of N(1), N(2)-diphenyl--anilinoisobutyramidine with PhPCl₂.For communication 5 see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1116–1121, June, 1993.     

Electrochemical behaviour of a molecular capsule based on methylviologen-resorcinarene and sulfonatomethylene-resorcinarene

A new molecular capsule based on viologen-resorcinarene and sulfonatomethylene-resorcinarene is synthesized and its redox-controlled stability is investigated.     

Iron(II)-induced degradation of antimalarial beta-sulfonyl endoperoxides: evidence for the generation of potentially cytotoxic carbocations

Reactions of antimalarial beta-sulfonyl endoperoxides 9 and 10, which, like yingzhaosu A (2), derive from the 2,3-dioxabicyclo[3.3.1]nonane system 3, with iron(II) salts were studied. Product analysis of the iron(II)-induced degradations provided evidence for the intermediacy of carbon-centered cyclohexyl radicals 20 and 31 and their possible oxidation to the corresponding carbocations 21 and 32. It is conceivable that the antimalarial activity of beta-sulfonyl endoperoxides of type 5 may derive from alkylation of vital intraparasitic biomolecules by free radicals and/or carbocations, generated within the malaria parasite through a similar iron(II)-induced degradation process.     

Reaction of aryl-substituted glycineamidines with oxalic acid derivatives

The reaction of N¹,N²-diaryl-N-arylglycineamidines with oxalyl chloride and diethyl oxalate leads to 1,4-diaryl-5-aryliminopiperazine-2,3-diones and 1,3-diaryl-4-aryliminoimidazolidin-2-ones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 230–232, January, 1991.