We have developed a new waveguide for 2.45GHz microwave which is equipped an aluminum block jacket thermostat, and built up a novel microwave synthesizer which can perform chemical reactions even at low temperatures with continuous microwave irradiation. Applying this for solid-phase peptide synthesis (SPPS), we successfully obtained some advantages. Reactions were accelerated even at lower temperatures. Microwave unique effect could be clearly observed. Only small excess reagents (ex. 1.2 equivalent of Fmoc-amino acids and condensation reagents) were enough in microwave supported SPPS even at low temperatures, though large excess (more than five equivalent) of reagents are commonly used. As glycosylated amino acid synthons are expensive and relatively unstable, also as glycopeptides are potentially suffered epimerization and are easily to be decomposed by elimination of sugars, microwave supported SPPS at low temperatures gave big advantages for glycopeptide synthesis.
