J. M. Aizpurua

N,N-Dimethylchlorosulfitemethaniminium chloride (SOCl2-DMF) a versatile dehydrating reagent.☆

Abstract N,N-dimethylchlorosulfitemethaniminium chloride formed from thionyl chloride and dimethylformamide was found and efficient reagent for the synthesis of acyl azides from carboxylic acids and nitriles from oximes. It is also highly efficient for the direct synthesis of beta-lactams from carboxylic acids and imines avoiding the use of acid chlorides.

Fromβ-lactams toα- andβ-amino acid derived peptides

SummaryThe potential ofβ-lactams as intermediates for the access toα- andβ-amino acid-derived peptides is shortly reviewed, with major focus on the technologies developed in our group. The two general strategies lie, on one side, in the oxidative ring expansion of 3-hydroxyβ-lactams toN-carboxyα-amino acid anhydrides or Leuchs anhydrides and subsequent coupling withα-amino acid esters and, on the other side, in the nucleophilic ring opening ofN-Boc-β-lactams. Both approaches have been successfully applied to the synthesis ofα,β-diamino acid,α-amino-β-hydroxy acid, polyhydroxylatedα-amino acid,α,α-disubstitutedα-amino acid,β-amino acid,β-amino-α-hydroxy acid andβ,β-disubstitutedβ-amino acid derived peptides. Because of the mild reaction conditions needed for the above transformations and the highly stereoselective procedures employed for the construction of the startingβ-lactam ring, the whole process allows the production of optically pure final products.

Concise synthesis of α-alkyl α-amino acids and their incorporation into peptides viaβ-lactam-derived α-amino acid N-carboxy anhydrides

α-Hydroxy β-lactams in which C4 exists as a quaternary carbon are transformed in a single one-pot operation into α,α-dialkyl α-amino acid N-carboxy anhydrides providing a new approach to conformationally restricted peptide segments from non α-amino acid precursors.

N-alkylydene[bis(trimethylsilyl)methyl]-amines: a new series of stable imines

Abstract Reaction of [bis(trimethylsilyl)methyl]amine with aldehydes, leads to Schiff bases with unexpected remarkable stability.