• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.919-922
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• 2000

The cyclization reaction of N-(2-hydroxyethyl)-N'-phenylthioureas 2 containingambident nucleophile was ex-amined in the combination of a variety ofbases and p-toluenesulfonyl chloride (TsCl).N-(2-Hydroxyeth-yl) thioureas 2 were readily obtained in high yields from the reaction of the corresponding 1,2-aminoalcohols with phenyl isothiocyanate, avoiding the need for O-protection.The use of a one-pot reaction (NaOH/TsCl) was found to be most effective in producing the requisite 2-phenylaminothiazolines (S-cyclization) 3 in the case ofthioureas 2a-2e derived from N-unsubstituted aminoalcohols,while in the thioureas 2f and 2g prepared from N-substituted aminoalcohols the combination of Et3N and TsCl led to the S-cyclization products.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.153-158
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• 1996

The synthesis of common skeleton of podosporin A and aureol was studied through cationic olefin cyclization as a key step. The generation of thermodynamic silyl enol ether or enol acetate under known conditions gave regioselectivity of 88:12. The enolate alkylation of 2,3-dimethylcyclohexanone with 2,5-dimethoxybenzyl bromide at the more substituted site via lithium enolate gave poor yield. In this case an organozincate or an ammonium enolate also proved to be ineffective or not practical in terms of yield. Side chain elongation of the substituted cyclohexanone 13 through Grignard reaction, Wittig reaction, or Shappiro reaction did not proceed because of steric hindrance and side reactions. However, Stille coupling reaction via enol triflate produced the desired product 18 in high yield. The advanced intermediate 22, which was efficiently synthesized from 18, produced 24 instead of the desired product under a cationic olefin cyclization condition, indicating that the cyclization occurred in a stepwise mannervia the organomercury intermediate 23.

• Bulletin of the Korean Chemical Society
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• v.31 no.3
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• pp.708-711
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• 2010

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1443-1444
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• 2008

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.347-350
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• 2002

Wholly aromatic polybenzoxazoles(PBO) are well established as high performance materials with excellent thermal stability and mechanical properties. Heterocyclic precursor polymers such as polyhydroxyamides(PHA) have been interested in the field of high performance flame retardant polymers.[1] Precusor polymers have the advantages that they are easier to process, don't require strong solvents and can adsorb large amounts of heat energy during the cyclization process. (omitted)

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.229-230
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• 2005

• YAKHAK HOEJI
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• v.34 no.5
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• pp.287-290
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• 1990

An efficient stereoselective synthetic route to carbocycle is described. 1,1,2-Trisubstituted cyclopentane was synthesized from allylic carbonate by Pd(0) catalyzed cyclization.

• YAKHAK HOEJI
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• v.31 no.6
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• pp.370-375
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• 1987

1, 4-Benzodiazepin 5-one was prepared from 2-aminobenzamide derivatives by acid catalyzed intermolecular cyclization. N-Alkylation of 2-aminobenzamide with $\alpha$-bromo acetaldehyde diethylacetal to 2(2', 2'-diethoxyethyl) aminobenzamide (I) and subsequent treatment of I with acid gave 1, 4-benzdiazepin 5-one, where as the acetyl derivatives of I did not react to 1, 4-benzodiazepin 5-one but to methyl 4-quinazolone (IV).

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.599-605
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• 2013

Some N-acetyl pyrazoles including 1-(3-(3,4-dichlorophenyl)-5-(substituted phenyl)-4,5-dihydro-$^1H$-pyrazole- 1-yl) ethanones have been synthesised by solvent free cyclization cum acetylation of chalcones like substituted styryl 3,4- dichlorophenyl ketones using hydrazine hydrate and acetic anhydride in presence of catalytic amount of fly-ash: $H_2SO_4$ catalyst. The yield of these N-acetyl pyrazole derivatives are more than 75%. The synthesised N-acetyl pyrazoline derivatives were characterized by their physical constants and spectral data.

• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.1009-1018
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• 1996

A study on the application of vinyl radical cyclization via free radical allylation reaction in the synthesis of various carbocyclic compounds is described. In connection with this study, a new allyl transfer reagent, 2-bromo-3-(phenylthio)propene 1 is developed and it was shown that vinyl radical cyclization through free radical allylation reaction using reagent 1 provides a valuable approach to carbocyclic systems with a reactive exo-alkylidene moiety, which is advantageous for further transformations.