A. É. Shipov

A Practical and Efficient Green Synthesis of β-Aminophosphoryl Compounds via the Aza-Michael Reaction in Water

Abstract Application of water as a solvent (without any cosolvent) promotes the aza-Michael reaction of diethyl vinylphosphonate and diphenylvinylphosphine oxide with a wide range of N-nucleophiles. The solubility of the starting phosphorus substrate in water does not play a crucial role in the reaction course, decreasing to some extent the reaction rate. The reaction can be performed either at room temperature or under reflux to afford the corresponding β-aminophosphonates and β-aminophosphine oxides in excellent yields and of high purity via a simple freeze-drying isolation procedure. Application of basic catalysts makes possible the addition of weak nucleophiles such as α-amino acids and their phosphorus analogues; that is, α-aminophosphonic acids. The aqueous aza-Michael reaction allowed us to easily perform double phosphorylation of primary amines including polyamines using a reactant ratio (phosphorus substrate: amine) of 2:1.

Arbuzov rearrangement in the 1,3,2-oxazaphosphinane series

Reactions of 2-alkoxy-1,3,2-oxazaphosphinanes (including 3-alkyl derivatives) with methyl and ethyl bromoacetates give two types of Arbuzov rearrangement products (cyclic and acyclic ones). The ratio between their yields is virtually independent of the nature of the substituent in position 3 of the starting reagent, being mainly determined by the nature of the substituent in the phosphorus bound alkoxy group and varying from 96 : 4 to 2 : 98. Acyclic products can be converted into cyclic ones.

1,3,2-Oxazaphosphinane analogs of phosphorylacetic acid derivatives: synthesis and properties

Reactions of 2-AlkO-1,3,2-oxazaphosphinanes with alkyl N-haloacetylamino or N-chloromethyl-N-methoxycarbonylamino carboxylates mainly give products with retention (Alk = Me) and opening of the ring (Alk = Et). In aqueous solution, cyclic products with the N-isopropyl group are only stable, while the rest undergo hydrolysis with cleavage of the P-N bond of the ring. Oxazaphosphinane analogs of phosphorylacetamide and phosphorylacetohydrazide were synthesized.

Hydrogen bonding and association of certain phosphadepsipeptides

1. n nIR spectroscopy has been used to study intermolecular and intramolecular hydrogen bonding in certain phosphadepsipeptides. n n n n n2. n nIn the condensed phase, these compounds associate through the formation of intermolecular hydrogen bonds in a process involving participation of the COOH and NH groups. n n n n n3. n nIn solution, it is only those compounds which contain open COOH groups which undergo appreciable association; the remaining compounds form intramolecular hydrogen bonds in dilute solution, the bonding process involving NH group participation.

Diastereomeric anisochronism in rapid interaggregate exchange

1. n n31P−{1H} NMR was used to study the dependence of RR, SS, RS, and SR stereoisomers of the compound n n

Synthesis of 1,3,2-Oxazaphosphorinane Derivatives under the Phase Transfer Conditions

begin{array}{*{20}c} {CH_3 } backslash P / {C_2 H_5 O} end{array} begin{array}{*{20}c} O / / backslash {SCH_2 CONHCH(C_3 H_{7 - i} )COOH} end{array}

Study of diastereomeric anisochronism of some O-ethyl methyldithiophosphonates that contain a second chiral center in the thiol group

n nin various mixtures in chloroform (cone. 0.4 mole /liter) on the stereoisomeric composition in the temperature range from −60 to 50°C. The statistically controlled intermolecular association of the chiral molecules strongly affects the value of the chemical shifts. n n n n n2. n nA theory was constructed to explain the chemical shifts under the influence of the interactions of chiral molecules of a mixture under conditions of statistical control. n n n n n3. n nThe application of the proposed theory towards a quantitative interpretation of the observed effects permits the determination of stereoselective intermolecular association parameters for the stereoisomers in the liquid phase. The temperature dependence of the stereoselectivity of association was studied.

Investigation of diestereomeric anisochronicity of O-ethylmethyldithiophosphonates, containing a N-methylvaline residue in the alkthiol group

Depending on steric hindnanus at the nitrogen atom interaction of 2-alkoxy-3-alky(aryl)-1,3,2-oxazaphosphinanes with alkyl chloroformates proceeds according to the Arbuzov reaction or with the formation of acyclic chlorofosphites.