Development of novel polymer-type dehydrocondensing reagents comprised of chlorotriazines.

A novel immobilized dehydrocondensing reagent comprised of a triazine-type dehydrocondensing reagent itself in a polymerized form was synthesized by copolymerization between tetra(ethylene glycol) bis(dichlorotriazinyl) ether and tris(2-aminoethyl)amine.

Development of a simple system for dehydrocondensation using solid-phase adsorption of a water-soluble dehydrocondensing reagent (DMT-MM).

It has been indicated that hydrophilic solid powder to which aqueous solution of a novel dehydrocondensing reagent DMT-MM is adsorbed becomes a simple solid-phase dehydrocondensing reagent of low cost. Reaction in a liquid--liquid biphasic system on the surface of a solid phase with a large area was accelerated by suspending this powder in a dichloromethane solution of a carboxylic acid and an amine to be condensed. The reaction was rapid with a high yield despite the heterogeneity of the system.

A racemization test in peptide synthesis using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM).

Racemization of the C-terminal amino acid (Ala) has been studied in various solvents during coupling between 4-methoxybenzyloxycarbonyl (Z(OMe))-Gly-L-Ala-OH and phenylalanine benzyl ester (H-Phe-OBzl) with 4-(4,6-dimethoxy-1,3,5-thiazin-2-yl)-4-methylmorpholinium chloride (DMT-MM). The reaction occurred without substantial racemization in AcOEt, tetrahydrofuran (THF), N,N-dimethylformamide (DMF), CH3CN, and 2-PrOH, while a slight racemization was observed in dimethyl sulfoxide (DMSO), EtOH, and MeOH. The extent of racemization may correlate with the polarity of the solvents.