Mark S. Smyth

A general method for the preparation of benzylic α,α-difluorophosphonic acids; non-hydrolyzable mimemtics of phosphotyrosine

Abstract Methodology is presented for the preparation of heretofore unreported benzylic α,α-difluorophosphonic acids. Oxidation of benzylic α-hydroxyphosphonates using MnO 2 , provided a new route for the synthesis of benzylic α-oxophosphonates, which were then fluorinated using DAST. Hydrolysis of ester protecting groups yielded α,α-difluorophosphonic acids. These represent non-hydrolyzable mimetics of arylphosphates which could be of value in the study of cellular phosphotyrosine-utilizing signal transduction pathways.

Synthesis of 4-phosphono(difluoromethyl)-D,L-phenylalanine and N-boc and N-Fmoc derivatives suitably protected for solid-phase synthesis of nonhydrolyzable phosphotyrosyl peptide analogues

Abstract Synthesis of 4-phosphono(difluoromethyl)-D,L-phenylalanine as well as its diethyl phosphonate analogues bearing either Boc or Fmoc-amino protection are reported. The latter two derivatives were utilized for the solid-phase synthesis of SH2-related peptides containing nonhydrolyzable phosphotyrosyl mimetics.

Enantioselective synthesis of N-boc and N-fmoc protected diethyl 4-phosphono(difluoromethyl)-L-phenylalanine; agents suitable for the solid-phase synthesis of peptides containing nonhydrolyzable analogues of O-phosphotyrosine

Abstract Enantioselective convergent syntheses of N-Boc and N-Fmoc protected diethyl 4-phosphono(difluoromethyl)-L-phenylalanine are reported.

Deprotection and cleavage methods for protected peptide resins containing 4-[(diethylphosphono)difluoromethyl]-D,L-phenylalanine residues

Abstract Ethyl groups on 4-[(diethylphosphono)difluoromethyl]-D,L-phenylalanine are efficiently removed using S N 2-type acidic reagents. These methods were utilized for the solid-phase synthesis of SH2-binding peptides containing nonhydrolyzable phosphotyrosyl mimetics.

Spirocyclic nonpeptide glycoprotein IIb–IIIa antagonists. Part 3: synthesis and SAR of potent and specific 2,8-diazaspiro[4.5]decanes

The synthesis and biological activity of analogues containing spiro piperidinylpyridine and pyrrolidinylpyridine templates are described. The potent activity of these compounds as platelet aggregation inhibitors demonstrates the utility of the spiro structures as central template for nonpeptide RGD mimics.

Spirocyclic nonpeptide glycoprotein IIb-IIIa antagonists. Part 1: design of potent and specific 3,9-diazaspiro[5.5]undecanes.

The synthesis and biological activity of novel glycoprotein IIb-IIla antagonists containing the 3,9-diazaspiro[5.5]undecane nucleus are described. The potent activity of these compounds as platelet aggregation inhibitors demonstrates the utility of the spirocyclic structures as a central template for nonpeptide RGD mimics.

Spirocyclic nonpeptide glycoprotein IIb–IIIa antagonists. Part 2: design of potent antagonists containing the 3-azaspiro[5.5]undec-9-yl template

Abstract The synthesis and biological activity of novel glycoprotein IIb–IIIa anatagonists containing 3-azaspiro[5.5]undec-9-yl nucleus are described. The potent activity of these compounds as platelet aggregation inhibitors demonstrates the utility of the monoazaspirocyclic structure as central template for nonpeptide RGD mimics.

Norleucine as a replacement for methionine in phosphatase-resistant linear and cyclic peptides which bind to p85 SH2 domains

Abstract A Met residue in the pTyr+3 position has previously been shown to be an important determinant for high affinity binding of peptides to PI 3-kinase p85 SH2 domains. In the present work, a series of linear and cyclic peptides based on the sequence “Gly-pTyr-Val-Pro-Met-Leu” as well as analogues having pTyr replaced by the phosphatase-resistant pTyr mimetics, phosphonomethyl phenylalanine (Pmp) or difluorophosphonomethyl phenylalanine (F 2 Pmp), were synthesized and their binding potency in p85 SH2 domain preparations compared with corresponding peptides in which the Met has been substituted by Nle. Nle is a chemically more stable, isosteric Met homologue in which the sulfur has been replaced by a methylene. Significant binding potency was retained by the Nle-containing peptides, indicating that Met is not absolutely essential for high affinity binding to this SH2 domain.