V. Sreenivasa Reddy

Design and Development of the First Peptide-Chelating Bisphosphane Bioconjugate from a Novel Functionalized Phosphorus(III) Hydride Synthon

Remarkable oxidative stability is shown by the carboxylate-functionalized primary bisphosphane 1. Compound 1 can be used in conjugation reactions with biomolecules for functionalization through the COOH group without prior protection of PH2 groups. A novel water-soluble bisphosphane was obtained by reaction of the PH2 groups of 1 with formaldehyde under mild conditions.

Chemistry in environmentally benign media Part 1. Synthesis and characterization of 1,2-bis[bis(hydroxymethyl)phosphino]ethane (‘HMPE’). X-ray structure of [Pt{(HOH2C)2PCH2CH2P(CH2OH)2}2](Cl)2

The water-soluble bisphosphine, 1,2-bis(bis(hydroxymethyl)phosphino)ethane (1), was synthesized in near quantitative yield by the reaction of bisphosphine, H2PCH2CH2PH2, with an aqueous formaldehyde in the presence of K2PtCl4. The reaction of this water-soluble bisphosphine 1 with cis-Pt(COD)Cl2 affords the mononuclear bischelate complex, [Pt{(HOH2C)2PCH2CH2P(CH2OH)2}2](Cl)2 (2), in near quantitative yield. The new ligand and complex have been characterized spectroscopically and the structure of the metal complex, 2, was determined by X-ray crystallography. The Pt(II) complex 2 crystallizes in the orthorhombic space group Pbca(a=14.623(1), b=16.216(2), c=9.319(4) A) with Z=4. The final R value is 0.024.

In vitro and in vivo characterization of a 99mTc complex with tris(hydroxymethyl)phosphine (THP)

The water-soluble, monophosphine ligand tris(hydroxymethyl)phosphine (THMP) was complexed with 99mTc. The 99mTc-THMP was formed in high radiochemical purity by simply mixing 99mTcO4- with THMP over a wide pH range. In vitro and in vivo studies indicated the complex to be highly stable under the respective conditions. HPLC analysis indicated a singular species with a retention time identical to the known [ReO2(THMP)4]1 complex. Results show that the hydroxymethylphosphine functionality is attractive for use in designing new 99mTc radiopharmaceuticals.

Hydroxymethyl bis(phosphines) and their palladium(II) and platinum(II) complexes formed via biphasic reactions. Crystal structure of [Pd{(HOH2C)2PC6H4P(CH2OH)2}2]Cl2

The water-soluble bis(phosphines) 1,2-bis[bis(hydroxymethyl)phosphino]benzene and 1,2-bis[bis(hydroxymethyl)phosphino]ethane were synthesized in near-quantitative yields by the catalytic formylation of H2PC6H4PH2 and H2PCH2CH2PH2 in the presence of formaldehyde in aqueous media. Their reactions with cis-[Pt(cod)Cl2](cod = cycloocta-1,5-diene) and cis-[Pd(PhCN)2Cl2] produced water-soluble complexes [M{(HOH2C)2PC6H4P(CH2OH)2}2]Cl2(M = Pt 1 or Pd 2) and [Pd{(HOH2C)2PCH2CH2P(CH2OH)2}2]Cl23, respectively. All the compounds were characterized by 1H and 31P NMR spectroscopy. The structure of 2 was confirmed by X-ray crystallography.

Synthese des ersten Biokonjugats aus einem chelatisierenden Bisphosphan und einem Peptid ausgehend von einem neuartigen funktionalisierten Phosphor(III)-hydrid-Synthon

Eine bemerkenswerte Oxidationsbestandigkeit zeichnet das Carboxy-funktionalisierte primare Bisphosphan 1 aus. Es kann uber die COOH-Gruppe mit Biomolekulen zu Konjugaten verknupft werden, ohne das die PH2-Gruppen vorher geschutzt werden mussen. Ein neuartiges, wasserlosliches Bisphosphan wurde durch die Reaktion der PH2-Gruppen von 1 mit Formaldehyd unter milden Bedingungen erhalten.

Synthesis and characterization of dioxorhenium complexes derived from water-soluble diphosphine tetraphosphonates

Water-soluble diphosphine tetraphosphonates [(RO)2OPCH2CH2]2P–X–P[CH2CH2PO(OR)2]2(X = C6H4 or C2H4, R = Et or Me) were synthesized in near-quantitative yields by a base-catalysed Michael addition of appropriate P–H bonded compounds to vinylphosphonates in the presence of potassium tert-butoxide. The reactions of these compounds with [ReO2I(PPh3)2] in biphasic media (aqueous–organic) produced water-soluble dioxorhenium complexes of the type [ReO2{[(RO)2OPCH2CH2]2P–X–P(CH2CH2PO(OR)2}2]+ in near-quantitative yields. The water-soluble phosphines and their rhenium complexes were characterized by IR, 1H and 31P NMR and high-resolution fast atom bombardment mass spectral analysis.

Bisphosphanylhydrazides as Novel Chelating Phosphines in Transition Metal Chemistry - Synthetic and Catalytic Studies

Abstract: The synthesis of alkoxy- and aryloxy- functionalized bisphosphanyl hydrazides, (RO)2PN(Me)N(Me)P(OR)2, is described. Interaction of these ligands with transition metals, particularly rhodium(I), has been investigated. The steric effects around PIII centers have pronounced effects on the pathway of reactions of Rh(I) precursors. For example, the reactions of these ligands with [RhCl(CO)2]2 leads to the formation of carbonyl free, chlorobridged dinuclear complexes when the groups are relatively smaller (e.g., CH2CF3, Ph), whereas mononuclear carbonyl-containing complexes are formed with bulky substituents (e.g., C6H3Me2-2,6, C6H3(OMe)2-2,6).

New Directions in the Development of Water-Soluble Phosphines and Transition Metal Compounds

Abstract The water-soluble bisphosphines, 1,2-bis(bis(hydroxymethyl)phosphino)benzene (“HMPB”) (1) and 1,2-bis(bis(hydroxymethyl)phosphino)ethane (“HMPE”) (2) were synthesized in near quantitative yields by the catalytic hydroformylation of H2PC6H4PH2 and H2PCH2CH2PH2 in the presence of formaldehyde in aqueous media.1.2 The reactions of these chelating bisphosphines 1 and 2 with Pt(COD)Cl2 and Pd(PhCN)2Cl2 produced water-soluble Pt(II) and Pd(II) complexes M[(HOH2C)2PC6H4P(CH2OH)2]2Cl2 (M = Pt, 3; Pd, 4) and M[(HOH2C)2PCH2CH2P(CH2OH)2]2Cl2 (M = Pt, 5; Pd, 6) respectively. The reactions of 1 and 2 with Re(O2)I(Ph3)2 and Re(O)2(NHC5H5)4]Cl to produce new water-soluble Re(V) complexes are also described. All the new compounds were characterized by 1H and 31P NMR spectroscopy. X-ray structures of representative Pd(II) and Re(V) complexes as shown below confirmed the chemical constitution of this new generation of water-soluble metal complexes.

Methyl hydrazine as a building block for a bridge between phosphinoamine [R2P–N(R)–PR2] and phosphorus hydrazide [R2P–N(R)–N(R)–PR2]. Synthesis and coordination chemistry of a novel triphosphine [(Me2P)2N–N(Me)(PMe2)]

The reaction of methylhydrazine with dimethylchlorophosphine in the presence of triethylamine affords the new triphosphine (Me2P)2N–N(Me)(PMe2)1 in near quantitative yields, which represents a bridge between phosphinoamine [>P–N(R)–P P–N(R)–N(R)–P<]backbones; reaction of 1 with cis-[W(CO)4(NHC5H10)2] proceeds via two coordination modes to give M–P–N–P and M–P–N–N–P metallacyclic frameworks; the structure of the phosphinoamine coordinated part of 1 has been demonstrated by X-ray crystallographic investigation of 2.