Detail of "54745-92-5"

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Synthetic studies on quinoxaline antibiotics

Synthetic studies on quinoxaline antibiotics. III. Synthesis of nortriostin A, a triostin A analog lacking N-methyl groups on the cystine and valine residues. Shin, Masaru; Inouye, Ken; Higuchi, Naoki; Kyogoku, Yoshimasa (Shionogi Res. Lab., Shionogi and Co., Ltd., Osaka 553, Japan). Bull. Chem. Soc. Jpn., 57(8), 2211-15 (English) 1984.In this article, certain chemicals are used. One of their cas registry numbers is 54745-92-5 CODEN: BCSJA8. ISSN: 0009-2673. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Nortriostin A (I) was prepd. by conventional soln. methods. Thus, peptide II [Z = PhCH2O2C, MeBzl = CH2C6H4Me-4, R = Me3CO2C (Boc), R1 = CH2CCl3 (Tce)] was prepd. and then it was Tce- and Boc-deblocked to give II (R = Boc, R1 = H) and II (R = H, R1 = Tce), resp., which were coupled together by DCC/1-hydroxybenzotriazole to give peptide III (R = Boc, R1 = Tce). The latter was converted to III (R = H, R1 = succinimido), which was cyclized to give cyclic peptide IV (R2 = Z, R3 = MeBzl). The latter was Z-deblocked and then acylated with 2-quinoxalinylcarbonyl chloride (Qxc-Cl) to give IV (R2 = Qxc, R3 = MeBzl), which was MeBzl-deblocked by CF3CO2H/thioanisole to give dihydronortriostin A (IV; R2 = Qxc, R3 = H), which was oxidized by iodine to give I. Synthetic I did not exhibit antimicrobial activity at 100 mg/mL. NMR data indicated I exists as a single structure in soln. .

Synthetic studies on quinoxaline antibiotics

Synthetic studies on quinoxaline antibiotics. II. Synthesis of triostin A. Shin, Masaru; Inouye, Ken; Otsuka, Hideo (Shionogi Res. Lab., Shionogi and Co., Ltd., Osaka 553, Japan). Bull. Chem. Soc. Jpn., 57(8), 2203-10 (English) 1984. CODEN: BCSJA8. ISSN: 0009-2673. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Triostin A (I) was prepd. by soln. methods in which peptides II [Z = PhCH2O2C; R = Me3CO2C (Boc), R1 = H (III); R = H, R1 = CH2CCl3 (Tce) (IV)] were key intermediates. Thus, III was coupled with IV by DCC/1-hydroxybenzotriazole (HOBt) to give peptide V (R2 = Tce), which was Tce-deblocked by Zn/HOAc to give V (R2 = H) (VI). VI was converted to the succinimido ester, which was Boc-deblocked and then cyclized by treatment with EtN(CH2CHMe2)2 to give cyclic peptide VII (R3 = Z) (VIII). VIII was also prepd. from VI by Boc-deblocking followed by cyclization (e.g., DCC/HOBt).In this experiment, several chemicals are used like 54745-92-5 VIII was Z-deblocked and then acylated with 2-quinoxalinylcarbonyl (Qxc) chloride to give VII (R3 = Qxc), which was deblocked by HF/anisole and then oxidized by HF/MeOH to give I. Synthetic and natural I were indistinguishable according to chromatog. and NMR; synthetic I was as active as natural I against Bacillus subtilis PCI-219. .