Novel Reactivity Mode of Hydroxamic Acids:  A Metalla-Pinner Reaction

Abstract

The reaction between the nitrile complex trans-[PtCl(4)(EtCN)(2)] and benzohydroxamic acids RC(6)H(4)C([double bond]O)NHOH (R = p-MeO, p-Me, H, p-Cl, o-HO) proceeds smoothly in CH(2)Cl(2) at approximately 45 degrees C for 2-3 h (sealed tube) or under focused 300 W microwave irradiation for approximately 15 min at 50 degrees C giving, after workup, good yields of the imino complexes [PtCl(4)[NH[double bond]C(Et)ON[double bond]C(OH)(C(6)H(4)R)](2)] which derived from a novel metalla-Pinner reaction. The complexes [PtCl(4)[NH[double bond]C(Et)ON[double bond]C(OH)(C(6)H(4)R)](2)] were characterized by elemental analyses (C, H, N), FAB mass spectrometry, and IR and (1)H and (13)C[(1)H] spectroscopies, and [PtCl(4)[NH[double bond]C(Et)ON[double bond]C(OH)(Ph)](2)] (as the bis-dimethyl sulfoxide solvate), by X-ray single-crystal diffraction. The latter disclosed its overall trans-configuration with the iminoacyl species in the hydroximic tautomeric form in E-configuration which is held by N[bond]H...N hydrogen bond between the imine [double bond]NH atom and the hydroximic N atom.

Chemistry and Biological Activity of Platinum Amidine Complexes

“…The reaction of trans-[PtCl 2 (NCR) 2 ] (R= Me, Et, CH 2 Ph) with HN=C(NHPh) 2 gave [PtCl-{HN=C(NC(NHPh)=NPh)R}(NCR)] derivatives, but if the reaction is carried out for a prolonged time upon heating in the presence of 4 equiv HN=C(NHPh) 2 , the nucleophilic attack proceeds on both nitriles to yield the corresponding [Pt{HN=C(NC-(NHPh) = NPh)R} 2 ] derivatives containing two bidentate 1,3,5-triazapentadiene ligands. [73] The cyanoguanidine complex cis- [78,79] alcohols, [80,81] hydroxamic acid, [82] amino acid esters [83] ). Of particular synthetic relevance is the preparation of oxazolines by preliminary reaction of trans-[PtCl 4 (NCEt) 2 ] with amino alcohols H 2 NCRR 1 CR 2 R 3 OH having varying degrees of substitution at the methylene groups, which fosters selective nucleophilic attack by the ÀNH 2 moiety, subsequent liberation of the hydroxo-functionalized amidines by reaction with dppe, and final conversion of the amidine to the oxazoline promoted by zinc(II) chloride according to Scheme 12.…”

Coordination Aspects in Modern Inorganic Chemistry

“…Reactions of coordinated inorganic and organic ligands are of the high interest. In particular, in 1998-2007 reactivity of such ligands as nitriles (RCN) and oximes, coordinated to the ion Pt(IV) is intensively studied [50][51][52][53][54][55][56][57][58][59][60][61][62]. The main attention in these studies is given to the reactions of nucleophylic addition of various nucleophiles on the carbon atom of triple CN-bond of the nitrile fragment, whose electrophylic activation was reached because of its coordination to Pt(IV) 96.…”

Computational study on the mechanism of the three-component reaction of dimethylacetylene dicarboxylate and triphenylphosphine with 2-acetylbutyrolactone

“…9 The synthetic route leading to these products is depicted in Scheme 1. were carried out to confirm that the obtained transition states were connected both with the reactants and the products. 14 The electronic structures of stationary points were analyzed by the natural bond orbital (NBO) method. 15 In all of the suggested reaction routes, the optimized structures and the geometrical parameters of the reactants (1+2+3), intermediates and transition states were calculated at the B3LYP/6-31G level of theory.…”