Three‐Component Condensation Leading to β‐Amino Acid Diamides: Convergent Assembly of β‐Peptide Analogues.

Abstract

Melting points were uncorrected. 1 H NMR (500 MHz) and 13 C NMR (125 MHz) were taken on a Varian Inova-500 spectrometer using CDCl 3 as solvent. Spectra were referenced to residual CHCl 3 (7.26 ppm for 1 H NMR) and CDCl 3 (77.0 ppm for 13 C NMR). Heteronuclear single quantum correlation (HSQC) and heteronuclear multiple bond correlation (HMBC) spectra were obtained on a Varian Inova-600 spectrometer using CDCl 3 as solvent. IR spectra were obtained on a Perkin-Elmer 16PC FT-IR spectrometer. Chemicals were obtained from Aldrich and Lancaster and used as received unless specified. Raney® 2800 nickel (Aldrich) was washed 3x with water to pH 7. Methanol was distilled from magnesium methoxide. Methylene chloride was distilled from CaH 2 . In reactions leading to diastereomers, spectroscopic data were reported for mixtures, unless specified otherwise.Representative procedure for the condensation of acyl cyanides, isonitriles and carboxylic acids.