Aminophosphonates

Simple esters cannot be allylated with allyl acetates, but the Schiff base 109 derived from o -amino acid esters such as glycine or alanine is allylated with allyl acetate. In this way. the o-allyl-a-amino acid 110 can be prepared after hydrolysis[34]. The Q-allyl-o-aminophosphonate 112 is prepared by allylation of the Schiff base 111 of diethyl aminomethylphosphonates. [35,36]. Asymmetric synthesis in this reaction using the (+ )-A, jV-dicyclohex-ylsulfamoylisobornyl alcohol ester of glycine and DIOP as a chiral ligand achieved 99% ec[72]. 

MIXED-LIGAND COMPLEXES (MLC) OF La WITH AMINOPHOSPHONIC ACID GRAFTED ON SILICA AND ARSENAZO I, III AND XYLENOLE ORANGE... 

OLEKSYSZYN Aminophosphonic acid synthesis Synthesis ol 1-aminoalkanephosphonic and 1-aminoa([Pg.278]

This group was used as a protective group and chiral directing group for the asymmetric synthesis of o -aminophosphonic acids. It is cleaved by acid hydrol-... 

Racemic and optically active a-aminophosphonic acids, derivatives of various heterocycles 97ZOR1605. 

Interesting developments in simple azetidine chemistry continue to be reported. The apparently general acetylative dealkylation of Af-tert-butyl-3-substituted azetidines 6 (R = Bu ) in the presence of boron trifluoride provides a two-step route to azabicyclobutane 7 from 6 (R = Bu, R = Cl). An aqueous solution of 7 reacts with ethyl chloroformate to give 8. Relatively unexplored 3-azetidinones 9 (R = Ac or NO2) are available from 3-acetoxya2Ktidine 6 (R = Ac, R = OAc) which is obtained by acetylative dealkyation of 6 (R = Bu , R = OAc) <96JOC5453>. 3-Substituted azetidines can be utilized in the synthesis of polyfunctional y- and S-aminophosphonic acid derivatives <95TL9201>. 

A. Aminophosphonic Acids.— The Michael addition of a dialkyl phosphite to acrylonitrile leads to C—P bond formation and the production in high yield of derivatives of 2-aminoethylphosphonic acid (45). This synthetic method appears to be preferable to those already described. ... 

Stereoselective hydrolysis of racemic l-(//-phenylacetylamino) alkanephos-phonic acids performed in the presence of penicillin acylase under the kinetic resolution conditions gave both the unreacted substrates and the products - the corresponding 1-aminophosphonic acids in high yields and with full enantioselec-tivity. The unreacted A -acyl derivatives were hydrolysed chemically and in this way each enantiomer of the free acid was obtained (Scheme 5). ... 

A number of 1- and 2-aminophosphonates were resolved by a straight CAL-B-promoted acetylation of the amino group in the substrates rac-SS. Surprisingly, ethyl acetate had to be used as an acetylating agent, since the commonly applied vinyl acetate reacted with aminoalkanephosphonates even in the absence of an enzyme (Equation 30, Table 6). ... 

Amine adducts of Ni11 diphenyldithiophosphinate with substituted ethylenediamins have been prepared and characterized. A dimeric pentacoordinate structure was proposed for [Ni2(S2PPh2)4(tmeda)].91s One crystal structure of a square planar Ni11 complex (351) with an aminophosphonate ligand has been reported.916... 

Fig. 37 Nitrogen-15 spectra of two aminophosphonates (structures as shown). 10-mm NMR tube, concentration 25% in CDC13, proton decoupling, relaxation delay 15 sec, measurement time 12 hours...

During the asymmetric synthesis of a-aminophosphonates (14 in Fig. 4.4), numerous attempts to cleave the benzylic C—N bond, involving catalytic or transfer hydrogenolysis, resulted in epimerization at the a-carbon.319... 

Biological Activity of Aminophosphonic Acids and Their Short Peptides... 

Tian-Hong Zhang et al. [652] have reported a new ion exchange chelating fibre with aminophosphonic and dithiocarbamate groups, based on polyacrylonitrile for the preconcentration of rare earth elements in seawater prior to their determination by inductively coupled plasma mass spectrometry. Rare... 

Aminophosphonic and Aminophosphinic Acids, Chemistry and Biological Activity, Kukhar, V.P. and Hudson, H.R., Eds., John Wiley Sons, Chichester, England, 2000 — Contributed chapters deal with syntheses and biological activity of compounds in the title categories. 

Symmetrical cyclic triazines (masked imines) have been used in reaction with diethyl trimethylsilyl phosphite to provide phosphonates bearing silyl-substituted a-aminophosphonates.349... 

Flynn, G.A., Beight, D.W., Bohme, E.H.W., and Metcalf, B.W., The synthesis of fluorinated aminophosphonic acid inhibitors of alanine racemase, Tetrahedron Lett., 285, 1985. 

Campbell, M.M. and Carruthers, N., Synthesis of a-aminophosphonic and a-aminophosphinic acids and derived dipeptides from 4-acetoxyazetidin-2-ones, Chem. Commun., 730, 1980. 

Tyka, R. and Oleksyszyn, J., a-Aminophosphonic Acids, Polish Patent 105,825, 1980. 

Glowiak, T. and Sawka-Dobrowolska, W., Absolute configuration of optically active aminophosphonic acids, Tetrahedron Lett., 3965, 1977. 

Lukszo, J., Kowalik, J., and Mastalerz, R, Advantages of using di(p-methyl-benzyl) hydrogen phosphite in the synthesis of aminophosphonates from aldimines, Chem. Lett., 1103, 1978. 

Wieczorek, J.S. and Gancarz, R., Aminophosphonic acid derivatives of fluroene, Rocz. Chem., 50, 2171, 1976. 

Hamilton, R., Walker, B., and Walker, B.J., A highly convenient route to optically pure a-aminophosphonic acids, Tetrahedron Lett., 36, 4451, 1995. 

---