Cyclo-cystine

Figure 33 The cyclo(Adm-Cyst)3 adopts a figure-eight-like helical structure. The chiral amino acid, cystine, configuration determines the helix disposition (rigjit-handed or left-handed helix). Adamantane plays an important role as a ring size controlling agent. Taken from Ref. [163] with permission.

The effect of reaction time on the major components of the reaction of cystine and DMHF in water is shown in Table IV. It is noteworthy that amounts of 2,4-hexanedione, 3,5-dimethyl-l,2,4-trithiolanes and thiophenones were found at a maximum after one hour. It was also found that the amount of 2-acetylthiazole increased with time and that acetol acetate decreased with time as expected. In the glycerol medium, the effect of reaction time on the major components is shown in Table V. Apparently, the 1,3-dioxo-lane, which is a ketal formed from glycerol and acetone, decreased over time. Also, long reaction time favors the formation of cyclic compounds, including 2,5-dimethyl-2-hydroxy-3(2H)-thiophene, cyclo-pentenones and 4,5-dimethyl-l,2-dithiolenone. 

Kamber, B. (1971) Cystine peptides from (S-acetamidomethyl-cysteine)-peptides through oxidation with iodine synthesis of cyclo-L-cystine. Helv. Chem. Acta 54, 927-930. 

C8H9CIN2O2, Benzenediazonium chloride - acetic acid, 33B, 243 C8HgN3Ni, Benzene-ammonia-nickel cyanide complex, 16, 521 C8H12N20ftS2f Cyclo-L-cystine - acetic acid, 40B, 546 C8H13N3O, 2,6-Lutidine-urea complex, 30B, 259... 

Ranganathan, D., Samant, M.R, Nagaraj, R., and Bikshapathy, E. Design, synthesis and membrane ion transport properties of cystine- and serine-based cyclo-4-oxa-heptane-l,7-bisamides. Tetrahedron Lett 2002,43 5145-5147. 

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