Hiroto Kudo

Synthesis and radical polymerization of an optically active monomer derived from cysteine

The synthesis and radical polymerization of N-methacryloyl-S-trityl-L-cysteine methyl ester [MA-C(Trt)-M] were examined. The radical polymerization was carried out at 60°C for 20 h in the presence of 2,2-azoisobutyronitrile (AIBN) in benzene, PhCl, and N,N-dimethylformamide (DMF) to afford the corresponding polymer with M n s in the range of 13200-130000 in good yields. In the radical copolymerizations of MA-C(Trt)-M with methyl methacrylate and trityl methacrylate, the specific rotations of the copolymers showed maximum values with MA-C(Trt)-M contents of 60 and 80 mol-%, respectively. The polymers were treated with HBr/CH 3 CO 2 H (30 wt.-%) to afford the trityl group-free polymers, which were insoluble in solvents due to the oxidative crosslinking reaction between the thiol groups.

Efficient synthesis of macrocycles by oxidation of cysteine-based dithiols

Abstract The cysteine-bridged macrocycles, 22–32-membered cyclic dimers could be synthesized with a high reagent concentration (1 M) in excellent yields by the oxidation of the cysteine-based compounds having dithiol groups.

Synthesis and reactions of cysteine‐based telechelic polymers

The radical polyaddition of N-4-vinylbenzoyl-L-cysteine methyl ester (VCM) was carried out in the presence of 2,2′-azobisisobutyronitrile (AIBN, 3 mol %) as an initiator in dimethyl formamide (DMF) with monomer concentrations of 0.5 and 1.0 M at 60 °C for 20 h under nitrogen atmosphere to afford the corresponding polymers [poly(VCM), PVCM] with number-average molecular weights (Mn)s of 5300 and 18,000 in 92 and 95% yields, respectively. The obtained polymers had a heterotelechelic structure with thiol and olefin end moieties. The radical polymerization of methyl methacrylate and trityl methacrylate was carried out in the presence of PVCM with AIBN (3 mol %) as an initiator in DMF at 60 °C for 20 h to afford the block copolymers with Mn values in the range of 13,000–26,800 in good yields. PVCM [Mn= 18,000; polydispersity (Mw/Mn) = 1.56] was treated with 4 equiv of NaOH aq. (1.0 M) to afford the polymer having carboxyl groups in the side chain with a Mn of 17,300 and Mw/Mn of 1.88 in 95% yield and was also oxidized to polysulfoxide and polysulfone with 4 equiv of H2O2 per sulfide unit in CH2Cl2 (1.0 M) for 20 h.