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Peptides containing N-methylamino acids can exhibit improved pharmacodynamic and pharmacokinetic profiles compared to nonmethylated peptides, and therefore interest in these N-methylated peptides has been increasing in recent years. Arodyn (Ac[Phe1,2,3,Arg4,D-Ala8]Dyn A(1–11)-NH2) is an acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al. J. Med. Chem. 2002, 45, 5617), and its analog [NMePhe1]arodyn shows even higher affinity and selectivity for κ opioid receptors (Bennett et al., J. Pep. Res. 2005, 65, 322). During the synthesis of [NMePhe1]arodyn analogs, the arodyn (2–11) derivatives were obtained as major products. Analysis indicated that Ac-NMePhe was lost from the completed peptide sequence during acidic cleavage of the peptides from the resin and that the acetyl group played an important role in this side reaction. Different cleavage conditions were evaluated to minimize this side reaction and maximize the yield of pure [NMePhe1]arodyn analogs. Modifications to the N-terminus of the peptides to prevent the side reaction were also explored. The incorporation of a heteroatom-containing group such as methoxycarbonyl as the N-terminal functionality prevented this side reaction, while the incorporation of a bulky acyl group could not. Substituting NMePhe with the conformationally constrained analog Tic (1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) also prevented the side reaction.

Laser cladding with large area has an important role in surface engineering applications, up to now not very much work has been done to produce surface cladding layers by 10KW–CW–CO2 laser. In order to clad a great roll in metallurgical industry, the wide-band scanning pyramid mirror system for 10KW CO2 laser cladding has been developed, and its clad experiments of NiCrSiB / A3 has been made. It was shown that a single pass width of 45mm and thickness of 1mm at 6–7KW / laser power can be obtained.Laser cladding with large area has an important role in surface engineering applications, up to now not very much work has been done to produce surface cladding layers by 10KW–CW–CO2 laser. In order to clad a great roll in metallurgical industry, the wide-band scanning pyramid mirror system for 10KW CO2 laser cladding has been developed, and its clad experiments of NiCrSiB / A3 has been made. It was shown that a single pass width of 45mm and thickness of 1mm at 6–7KW / laser power can be obtained.