• Bulletin of the Korean Chemical Society
• /
• v.34 no.2
• /
• pp.357-358
• /
• 2013

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.179.2-179.2
• /
• 2003

We have developed the novel one-pot synthetic method for regioselective and stereoselective N-protected amines through the reaction of various ethers with chlorosulfonyl isocyanate (CSI). Also, we found a novel technique to compare directly the stability of carbocations in the solution phase and established the stability order of the various carbocations. And we reported the cleavage of benzyl and p-methoxybenzyl protecting groups of alcohols and phenols in the presence of other functional groups using CSI. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.183.1-183.1
• /
• 2003

The synthesis of various cyclic carbamate compounds and amino alcohols has attracted attention in the past because of their potential as antibiotics, antitumor, analgenics, anticonvulsants. Several methods for the preparation of cyclic carbamate compounds have previously been reported including the use of heterocumulenes. We have recently described the novel synthetic method for N-protected amines from various ethers using Chlorosulfonyl isocyanate(CSI) and found that the mechanism of our CSI reaction is a competitive reaction of $S_N1$ and $S_ Ni$ mechanisms according to the stability of carbocation intermediates. (omitted)

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.342.1-342.1
• /
• 2002

6.7-Dicholroquinoline-5.8-dione reacted with 2-aminopyridine derivatives, Out of the four possible products which could be achieved in this reaction. condensation and rearrangement product. 4a.10.11-triazabenzo［3.2-a］ fluorine-5.6-dione was obtained as major product. The definite structure was identified with X-ray crystallographic study. (omitted)

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1996.04a
• /
• pp.166-166
• /
• 1996

A series of 6-(N-arylamino)-7-alkylthio-5,8-quinolinedione derivatives(SQ1-12) were newly synthesized for the evaluation of antifungal activities. 6-(N-Arylamino)-7-chloro-5,8-quinolinediones (RCKs) were treated with Na$_2$S/(CH$_3$)$_2$SO$_2$ in EtOH In give SQs. RCKs were prepared by regioselective nucleophilic substitution of 6,7-dichloro-5,8-quinolinediones with arylamines. In the presence of CeCl$_3$, the N-arylamino groups were introduced at the 6-position of 5,8-quinolinedione ring by the regioselective substitution. These derivatives 1-12 were tested for antifungal and also antibacterial activities, in vitro, against Candida sp., Aspergillus niger and Trichophyton mentagrophytes. The MIC values were determined by the two-fold dilution method.

• Archives of Pharmacal Research
• /
• v.17 no.3
• /
• pp.139-144
• /
• 1994

A series of 6-(N-aylamono)-7-chloro-5, 8-quinolinedione derivatives was newly synthesized for the evaluation of antifugal activities. 5-Amino-8-hydroxy-quinoline (II) was treated with $KCLO_3$ in HCl to give 6,7-dichloro-5,8-quinolinediones (III). 6-(N-Arylamino)-7-chloro5,8-quinolinediones 1-13 were prepared by regioselective nucleophilic substitution of III with arylamines. In the presence of $CeCl_3$, the N-arylamono groups were introduced at the 6-position of 5,8-quinolinedione ring by the regioselective substitution. These derivatives 1-12 were tested for natifungal and also antibacterial activites, in vitro, against Canadida albicans, Aspergillus nier, Tricophyton mentagrophytes, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coil. The MIC values were determined by the two-fold agar/steak dilution method. Newly obtained 6-(N-arylamino)-7-chloro5,8-quinolinedione derivatives showed potent antifungal and antibacterial activities. Among these derivatives, 1,3,5,7,8 and 9 showed more potent antifungal activities than fluconazole and griseofulvin. Also most of derivatives were found to be more active than ampicillin against gram-positive bacteria. 1 and 7 showed the very potent antifungal activities. 1 was the most efective in preventing the growth of Candida albicans, Aspergillus niger, Tricophyton mentagrophytes, Bacillus subtills and Staphylococcus aureus at MIC $1.6\;\mu{g/ml}$.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.4
• /
• pp.460-466
• /
• 2003

For the drug master file (DMF) of ketoconazole, four impurities (1-4) contained in ketoconazole were synthesized. During the synthesis of 2, a new synthetic method of 1,4-dihydropyrazine was established. To oxidize the aminoalcohol (2j) to the aminal (2j-1), the standard Swern oxidation condition was modified to mask the nucleophilicity of the amino group temporarily using one equivalent of acetic acid. Derivative 3 was synthesized via regioselective bromination at the 2 position of the 4-aminophenol derivative (3a) using $Br_2$ in the presence of p-TsOH. The etherification of aryl bromide with the phenol derivative (1f) was accomplished by a modification of the general Cu-mediated reaction condition using excess 1f itself as a solvent at elevated temperature (190 ℃).

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2003.11a
• /
• pp.116-116
• /
• 2003

In 1998, Osada and co-workers isolated 140 mg of a novel cytokine modulator from 18 L of the culture broth of Streptomyces RK95- 31 isolated from a soil sample in Hiroshima Prefecture. This new immunosuppressant was named (-)-cytoxazone and its absolute configuration was determined on the basis of its NMR, CD and X -ray analysis. It interferes with cytokine IL4, IL10 and IgG production by selective inhibition of the signaling pathway of Th2 cells, but not Thl cells. Inhibitors of Th2-dependent cytokine production have potential as potent chemotherapeutic agents in the field of immunotherapy. The (-)-cytoxazone is different from known immunomodulators such as FK 506 and rapamycin in respect of structure and biological activity. As such cytoxazone should be a useful tool for understanding signaling pathways in Th2 cells, the synthesis of (-)-cytoxazone is of interest for the development of new cytokine modulators.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.10
• /
• pp.2915-2920
• /
• 2013

Convenient synthetic method for 4-arylethylpyrazoles and 4-styrylpyrazoles was developed using ${\alpha}$-alkenyl-${\alpha},{\beta}$-enones readily accessed from the Morita-Baylis-Hillman reaction. For the synthesis of 4-arylethylpyrazole, the reactions with arylhydrazines needed to be carried out in o-dichlorobenzene under $N_2$ balloon atmosphere. On the other hand, 4-styrylpyrazoles required the reactions in ethanol under $O_2$ balloon atmosphere.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1531-1534
• /
• 2009

(2S,3R)-3-Hydroxy-2-(hydroxymethyl)-3,6-dihydro-2H-pyridine 8, an important precursor for the synthesis of polyhydroxylated piperidine azasugars, has been prepared from L-serine. Highly stereoselective nucleophilic addition to amino aldehyde 5 gave the corresponding allylic alcohol 6 which proceeded to give dihydro-2H-piridine 7a via a Grubbs II catalyzed RCM. Stereoselective H-bond directed epoxidation of allylic alcohol led to the oxiranyl alcohol 9 which was easily converted to L-deoxyaltronojirimycin by regioselective ring opening.