Agnes M. Modro

PHOSPHONIC SYSTEMS. 7. REACTIONS OF 2,3-EPOXYPHOSPHONATES WITH NUCLEOPHILES: PREPARATION OF 2,3-DISUBSTITUTED ALKYLPHOSPHONIC ESTERS AND RELATED SYSTEMS

Abstract Diethyl 2,3-epoxyalkylphosphonates react regioselectively with various nucleophilic reagents yielding 2-hydroxy-3-substituted alkylphosphonic esters. The 2-hydroxy functionality can be easily converted into an ester or ether derivative. The reaction of diethyl 2,3-epoxypropylphosphonate with ketone enamines does not lead to hydroxyketophosphonates, but results in the incorporation of the 3-phosphonopropylidene group (CH—CH2—CH2—PO3Et2) into the position 2 of the parent ketone.

Phosphoric amides. 15N NMR study of the P—N bonding in acyclic and cyclic compounds

31P and 15N NMR spectra of 11 cyclic and non‐cyclic phosphoramidates were measured. Comparison of the closely related structures demonstrated correlation between the bond angles at nitrogen and the 15N NMR chemical shifts and the 1J(P,N) coupling constants. 15N NMR parameters allowed the exo‐ and endocyclic nitrogens to be distinguished and could be related to the hydrolytic stability of the P—N bonds.

Phosphoric amides. Part 10. Base - promoted cyclization of phosphorotriamidates bearing the N-(2-chloroethyl) substituent, and the interconversion of cyclic products

Abstract N,N′-Diaryl-N″-(2-cholorethyl)phosphorotriamidates undergo base-promoted 1,3 and 1,5 cyclizations, yielding the N-phosphorylated aziridines and 1,3,2-diazaphospholidines, respectively. The former products are stable towards bases, while the latter undergo base-promoted ring contraction, resulting in the isomeric aziridine derivatives.

Lithiation of diethyl trichloromethylphosphonate and the transformations of the α-lithiated derivative

The lithiation of diethyl trichloromethylphosphonate below –100 °C leads to a stable α-lithiated derivative, but at temperatures of about –80 °C the lithiation is accompanied by spontaneous reactions leading to tetraethyl (chloromethylene)bisphosphonate as the exclusive product. Possible mechanisms of the reaction are discussed.

Reaction of O,O‐dialkyl alkylphosphonates with thionyl chloride. A remarkable effect of the O‐(2‐dialkylamino)ethyl substituent

Reaction of dialkyl alkylphosphonates with SOCl2 in the presence of DMF, reported by Maier, can serve as a convenient route to simple monoalkyl alkylphosphonochloridates. However, when a substrate contains a (2-dialkylamino)ethyl group as one of the ester functions, the course of the reaction is determined by the nature of the N-alkyl groups. With the NMe2 group present, reaction with SOCl2 occurs at nitrogen, and no exchange of groups at phosphorus takes place. The NEt2 group, on the other hand, directs the reaction to phosphorus, and the Maier reaction of the exchange of one ester group OR for Cl proceeds in high yields.

PHOSPHONIC SYSTEMS. 6. DIETHYL 2-METHYLPENTENYLPHOSPHONATES AS A MODEL FOR STUDIES OF THE STABILITY OF UNSATURATED PHOSPHONIC ESTERS

Abstract The composition of a thermodynamically controlled mixture of diethyl esters of α,β and β,γ-unsaturated phosphonates was determined by NMR spectroscopy and gas chromatography. The location of the double bond is determined by alkyl substitution and by hyperconjugation, but not by the position of the phosphorus-containing group

PHOSPHONIC SYSTEMS. PART 17. SOLUTION AND SOLID STATE STUDIES ON DIMETHYL 2-HYDROXY-3-BENZOYLPROPYLPHOSP

Abstract The crystal and molecular structure of dimethyl 2-hydroxy-3-benzoylpropylphosphonate (1) has been determined. P21/c, a = 11.989(3), b = 12.990(3), c = 8.601(3) A; V = 1339.1(7) A3. Molecular parameters indicate strong intramolecular interactions between the hydroxyl oxygen and the phosphorus atom. The hydrogen bonding involves the phosphoryl group as a donor, and occurs intermolecularly, yielding a dimeric arrangement of the molecules. The acid-catalyzed dehydration of 1, and the base-promoted elimination of the tosylate derivative, yielded the same (E) dimethyl 3-benzoyl-prop-2-en-ylphosphonate as the exclusive product.

Synthesis and Reactivity of Bicyclic Phosphoric (and Thiophosphoric) Amides

This work summarizes studies on the preparation, structure, and reactivity of a new heterocyclic system containing phosphorus and nitrogen: 2,8-disubstituted-2,5,8-triaza-1 u 5 -phosphabicyclo[3.3.0]octane 1-oxide (and 1-sulfide).

STRUCTURAL, SPECTROSCOPIC AND REACTIVITY STUDIES ON PHOSPHORIC AMIDES

A series of non-cyclic, cyclic and bicyclic phosphotriamidates has been sythesized and their structure, NMR spectroscopic characteristics and their chemical reactivity are discussed.

Phosphoric amides. Bridge effect in geminal coupling constants between 31P and 13C nuclei

Full NMR spectral characteristic of eight phosphoric amides is presented. The results show that the geminal coupling constants are strongly influenced by the atom located between the coupled nuclei. Spin–spin interactions 2J(31P,13C) seem to be transmitted in investigated rings mainly by the two‐bond pathway, and only to a small degree via three‐bond mechanism.