Jurjus Jurayj

Approaches to the synthesis of endothiopeptides: Synthesis of a thioamide-containing C-terminal bombesin nonapeptide

Abstract Several approaches have been investigated for the synthesis of a bombesin C-terminal nonapeptide analogue AsnGlnTrpAlaVAlGlyHisLeu-ψCSNHMet-NH2. A new activated dithioester 16 has been synthesized. Thioacylation of methionine methyl ester with 16 was always accompanied by racemization, resulting in the formation of diastereomeric mixtures of reaction products.

Synthesis of [L-3-deoxymimosine4]-angiotensin I as an approach to the preparation of selective protein-tyrosine kinase (PTK) inhibitors

Abstract tert-Boc-L-3-Deoxymimosine (13) and tert-Boc-D-Deoxymimosine (16) were prepared in two steps from tert-Boc-L-asparagine and tert-Boc-D-asparagine, respectively. Both 13 and 16 were determined to be optically pure by derivatization with Marpheys reagent. Activation and coupling of 16 to L-isoleucine methyl ester resulted in a diastereomeric mixture of products containing 96% of the DL diastereomer and 4% of the LL diastereomer. [L-3-Deoxymimosine4]-angiotensin I was synthesized from 13 as an approach to the design and synthesis of selective protein-tyrosine kinase (PTK) inhibitors.

A Synthesis of 2-Alkyl and 2-Benzyl Substituted Acrylonitriles from 2-Alkyl and 2-Benzylidene Cyanoacetate Esters under Mild Conditions

Abstract Substituted cyanoacetate esters were reduced with sodium borohydride to give good yields of the corresponding β-hydroxynitriles, which were converted to 2-substituted acrylonitriles by base catalyzed elimination of their sulfonate esters.