• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2021-2026
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• 2005

The oxidation of cytidine 1 and inosine 5 by sodium metaperiodate followed by the reaction of the product with $CH_3I$ in NaOH afforded 2',4'-dihydroxyhexopyranosyl derivatives 2 and 14 respectively. The reaction of thiophene-2-carboxylic acid or furfural with cytidine were taken place via cycloaddition afforded adducts 3 and 4 respectivily. The bromination of inosine 5 or its 2',3'-O-isopropylidine inosine 6 led to the formation of 8-bromoanalogue 7 and 8, respectively. The reaction of 8-bromo-2',3'-O-isopropylidine inosine (8) with ethylglycinate hydrochloride afforded 8-ethoxycarbonylmethylaminoinosine 9. The alkylation of the compound 6 with urea led to the formation of 3-carbonylaminoinosine 10. The oxidation of 6 with DCC afforded 4'-formyl derivative 11, which on reaction with ethyl glycinate hydrochloride followed by reaction with sodium cyanoborohydride afforded 12, while the treatment of dialdehyde inosine 13 with ethyl cyanoacetate in the presence of 0.5 N NaOH afforded compound 15.

• 한국응용과학기술학회지
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• 제17권2호
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• pp.113-119
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• 2000

Alkylation of phenol with tert-butanol in the liquid phase on mordenite was studied. The influence of many reaction parameters such as calcination temperature, reaction temperature, t-butanol/phenol molar ratio on catalytic properties was discussed. The main products were 2,4-di-t-butylphenol, o-t-butylphenol, p-t-butylphenol, the last of these was wanted product. In order to enhance the selectivity of p-t-butylphenol, optimum conditions were recommended at $500^{\circ}C$ calcination temperature, $140^{\circ}C$ reaction temperature, 1.0 molar ratio of reactants over mordenite. P-t-butylphenol was formed with 90% isomer selectivity at optimum conditions after 4hr reaction. On the basis of the behavior obtained in the cases mentioned, optimum conditions and catalytic properties for t-butylation of phenol were provided.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2953-2958
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• 2013

A noble phenylsulfonyl reagent 8 having ${\alpha}$-oxo (cyanomethylene)triphenylphosphorane ylide subunit readily condensed with various alkyl halides under basic conditions to afford ${\beta}$-alkyl-${\alpha}$-oxo-${\beta}$-phenylsulfonyl (cyanomethylene)triphenylphosphorane ylides 9 in excellent yields. These sulfonyl ylides 9 were then reductively desulfonylated with $Na(Hg)/Na_2HPO_4$ in the presence of methanol to provide ${\alpha}$-keto (cyanomethylene)-triphenylphosphorane ylides 2' in good to excellent yields. Our new synthetic approach offers an expeditious access to various ${\alpha}$-keto (cyanomethylene)triphenylphosphorane ylides from alkyl halides utilizing a new phenylsulfonyl reagent as the key reagent under mild reaction conditions in good overall yields.

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.959-965
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• 2005

Investigation of structure-activity relationships of novel quinazolines has identified 7,8-dihydro-[1,4]dioxino-[2,3-g]quinazolines as a potent inhibitor of EGFR. These compounds have a benzodioxane framwork, which was prepared by regioselective O-alkylation of ethyl 3,4-dihydroxy benzoate by epoxide ring opening. Compounds 3f and 3k were more potent than ZD-1839 in EGF enzyme and EGFR autophosporylation inhibition assays.

• Archives of Pharmacal Research
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• 제28권8호
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• pp.877-884
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• 2005

A number of wogonin derivatives have been synthesized as congeners of wogonin and evaluated for their inhibitory activities of $PGE_2$ production. Wogonin derivatives modified at the B ring of wogonin were obtained from 2,4-Dihydroxy-3,6-dimethoxyacetophenone (1) via several steps. Most wogonin derivatives exhibited much reduced inhibitory activities against COX-2 catalyzed $PGE_2$ production compared to that of wogonin. Alkylation of 5,7-phenol groups and substitution at the B ring of wogonin generally caused reduction of inhibitory activity.

• Archives of Pharmacal Research
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• 제19권3호
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• pp.240-242
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• 1996

We have reported the convenient biomimetic methodology for the synthesis of all kinds of substituent pattern benzo[c]phenanthridine alkaloids (Hanaoka et al., 1990; Hanaoka et al., 1991). Regioselective demethylation of C-8 position on oxyfagaridine (5), an intermediate for the synthesis of Fagaridine (4), would afford the precursor for the synthesis of Isofagaridine because the strong hydrogen bonding between amide and hydroxyl group of C-7 position probably resists to be reacted with week base and electrophiles. Thus, a selective alkylation of dihydroxy compound supposed to be possible and be lead to the target compound, Isofagaridine.

• Bulletin of the Korean Chemical Society
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• 제9권1호
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• pp.52-55
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• 1988

Starting with readily available p-tert-butylcalix[4]arene 3 tert-butyl groups are removed by $AlCl_3$-catalyzed de-alkylation reaction, and the calix[4]arene 4 formed is converted into the tetraacyl esters. These compounds undergo Fries rearrangement to yield p-acylcalix[4]arenes. p-Acetyl, p-propionyl, p-butyryl, and p-benzoylcalix[4]arene 10, 11, 12 and 14 are synthesized in 70-80% yields by treatment of the corresponding esters 5, 6, 7 and 9 with $AlCl_3$ in nitrobenzene. When the tetraisobutyryl ester 8 was treated with the same condition, only two isobutyryl groups were rearranged to the para-positions of calix[4]arene, and remaining two groups were simply cleaved.

• 폴리머
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• 제30권6호
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• pp.556-562
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• 2006

분자량이 다른 두 가지 폴리(4-비닐피리딘) (Mw=50 kg/mol 및 200 kg/mol)을 알킬기의 탄소수(m)를 변화시키면서 N-알킬화시켜 이온성 고분자를 합성하였다. 알킬화제로서 디메틸 설페이트(m=1) 및 브롬화 알칸(m=5, 8, 12, 16 및 22)을 사용하였다. 합성한 이온성 고분자의 조성은 NMR 분광분석법 및 원소분석법을 사용하여 결정하였다. 그 결과로써 거의 완전한 4차 알킬화 반응에 의해 전해질 고분자가 얻어졌음을 알 수 있었다. 합성한 전해질고분자의 수용액에 도데실 황산 소듐(SDS)을 첨가 시 발생되는 탁도 변화를 조사하여 임계응집농도(CAC)를 결정하였으며, 이러한 CAC가 고분자의 분자량, N-알킬기의 길이 및 NaCl의 농도 변화에 어떻게 의존하는가를 조사하였다. 결과로써 폴리(4-비닐피리딘)의 분자량이 클수록 또한 알킬 곁사슬의 길이가 길수록 더 적은 양의 SDS 첨가로도 응집체가 형성되었음을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.113-117
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• 1993

Good yield synthetic routes for the production of new B-alkyl-dithiaborane clusters are reported. The syntheses of the B-alkyl-dithiaboranes are based on the use of Fischer-type carbene reagents to activate the B-H bonds of dithiaborane for alkyl-addition reactions and are the first examples of transition-mediated reactions of dithiaborane to be reported. Thus, reactions employing arachno-$S_2B_7H_8$- and $(CO)_5M{C(R_1)R_2}$ (M = Cr, W; $R_1 = CH_3,\;C_6H_5;\; R_2 = OCH_3,\;SC_6H_5)$ were found to yield the intermidiate anions I, $[(CO)_5M{C(R_1)R_2S_2B_7H_8}]^-$, which upon protonation gave the corresponding neutral, air-sensitive cluster arachno-4-$RCH_2-6,8-S_2B_7H_8(R=CH_3,\;IIa;\;C_6H_5,\;IIb)$ range from 30 to 35% yield. Complexes IIa and IIb are isoelectronic with arachno-6,8-$S_2B_7H_9$ and, on the basis of the spectroscopic data, are proposed to adopt a similar arachno cage geometry in which an $RCH_2$ units are substituted to 4 position boron atom of the arachno-6,8-$S_2B_7H_9$.

• Bulletin of the Korean Chemical Society
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• 제27권7호
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• pp.986-990
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• 2006

As key nucleoside intermediates for the preparation of cyclic adenosine diphosphate ribose (cADPR, 1) analogues, 8-alkyl-2' (or 3')-azido(or amino)-adenosine derivatives (16-19) were successfully prepared by alkylating selectively protected adenosine derivatives (12, 13) via Pd(0) catalyzed cross-coupling reaction with tetraalkyltin reagents, followed by the sugar modification of these 8-alkyl-adenosine derivatives according to our precedent procedure. Compared to other precedent procedures, our 8-alkylation methodology using selectively TBDMS-protected 8-alkyl adenosine derivatives as starting materials will be utilized very conveniently to prepare highly functionalized adenosine analogues, which will be serve as key intermediates for the cADPR.