• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1993.04a
• /
• pp.34-35
• /
• 1993

The Development of new asymmetric induction methods useful for syntheses of biologically active natural products and drugs, using C4-chiral 1,3-th-iazolidine-2-thiones, has been a recent focus of interest. 1-8) The present account describes the significance of particular heterocycles in the synthetic development of new 1${\beta}$-substituted carbapenems. A fungal metabolite, (＋)-thienamycin (1) has attracted one's attention as a hopeful candidate for new-generation antibiotic drugs because of its strong antimicrobial activities and wide antimicrobial spectra due to the extensive inhibition against various ${\beta}$-lactamases. However, it has been serious problems toward a practically useful drug that (＋)-thienamycin is fairly labile in the solution and can be metabolized by renal dehydropept- idase-I (DHP-I). Recently, a Merck Sharp ＆ Dohme research group exploited a non-natural ${\beta}$-lactam, imipenem (2) which has been appeared in the drug market as the first carbapenem-type antibiotic drug. 9) However 2 must be used with a DHP-I inhibitor, cilastatin sodium (3).9) Thus, a 1,${\beta}$-methyl- carbapenem derivative 4 has been disclosed by the same group. 10) It seems to be more hopeful candidate as a new-generation antibiotic because it can directly resist against metabolism by the renal DHP-1 without an enzyme inhibitor 3. 10)

• Archives of Pharmacal Research
• /
• v.23 no.2
• /
• pp.128-138
• /
• 2000

In continuation of the previous work (Fathalla, 1992) on the synthesis of some heterocycles containing uracil moiety, we report herein the incorporation of uracil moiety into cyan-opyridine thione, thiosemecarbazone, semicarbazone, cyanopyridine, ami nocyano pyridine, isoxazoline, pyrazoline, pyrimidine, triazolo pyrimidine, pyran, selena and thiazole derivatives which might modify their biological activities. The biological studies revealed that the chemical compound III f showed high molluscicdal activity than other compounds. The profile of the nucleoprotein extracted from chemically (compound IIIc, e, f and g) treated or UV-irradiated B.alexandrina snails did not show appreciable differences when compared to non-treated (native) snails by using SDS-PAGE, where no obvious qualitative or quantitative differences were observed. Immunization of experimental animals with the nucleoprotein extracted from native, chemically (compound III f ＆ g) treated or physically treated B.alexandrina snails induced significant protection against challenge with normal S.mansoni cercariae, as compared to the non-immunized challenged control. As well as , a decrease in the number of granuloma formation and the size range of granuloma was also observed in immunized animals. It is concluded that, compounds III f and g have a potent molluscicidal activity. They also induced chemical modification comparable to that induced by physical treatment in the snail's nucleoprotein, which could possibly be used in immunization against S. mansoni infection.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.11
• /
• pp.3265-3271
• /
• 2010

A series of 6,7,8,9-tetrahydro-5H-5-hydroxyphenyl-2-benzylidine-3-substituted hydrazino thiazolo (2,3-b) quinazolines have been synthesized to meet the structural requirements essential for anti-inflammatory and antinociceptive properties. The synthesized series of heterocycles, 6,7,8,9-tetrahydro-5H-5-hydroxyphenyl-2-benzylidine-3-substituted hydrazino thiazolo (2,3-b) quinazoline by the reaction of 6,7,8,9-tetrahydro-5H-5-hydroxy phenyl thiazolo (2,3-b) quinazolin-3(2H)-one with appropriate hydrazine hydrate and ketones/aldehydes in the presence of anhydrous sodium acetate and glacial acetic acid as presented in Scheme 1. Their antinociceptive activity were evaluated by tailflick technique, anti-inflammatory was evaluated by carrageenan-induced paw edema test and their ulcerogenicity index determined by reported protocol. The compounds exhibited the lowest ulcer index ($0.51{\pm}1.63$, $0.48{\pm}1.28$ and $0.50{\pm}1.53$, respectively. The 6,7,8,9-tetrahydro-5H-5-hydroxy phenylhydroxy-2-benzylidine-3-(N'-3-pentylidenehydrazino) thiazolo (2,3-b) quinazoline and 6,7,8,9-tetrahydro-5H-5-hydroxy phenyl-2-benzylidine-3-(N'-2-pentylidene-hydrazino) thiazolo (2,3-b) quinazoline exhibited the most potent antinociceptive and anti-inflammatory activities.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.2
• /
• pp.377-380
• /
• 2008

Ground state structures and ring flipping transition states of eight- and seven-membered silicon containing heterocyclic compounds such as dithienodisilacyclooctatriene and oxadithienodisilacycloheptadiene derivatives, respectively have theoretically been investigated. Although the bithienylene moiety of the derivatives does not change the ground state structures, they significantly increase the ring flipping barrier by 13-17 kcal/mol in the case of the eight-membered rings (2, 3, and 4) in comparison with that of silicon containing heterocyclic compound 6, chosen as a model. The same moiety increases the flipping barrier of seven-membered ring (5) is only slightly (3.3 kcal/mol) in comparison with that of model compound 7. Hence, it has been concluded that not only the existing ring strain of eight-membered ring but also the bithienylene moiety collectively increases the ring flipping barrier so as to prevent such conformational changes explaining anomalous NMR behaviour of dithienodisilacyclooctatriene derivatives (2-4). In contrast, the effect of substituents R1 and R2 at the olefinic carbons of the eight-membered ring on the flipping barrier turned out to be mild.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.10
• /
• pp.1545-1550
• /
• 2004

meso-Functionalized dipyrromethanes 6-10 were synthesized by acid-catalyzed addition of pyrrole to ${\alpha}$-position of 2-alkenyl pyrroles. The regiochemistry of the reaction can be explained by either the formation of more stable carbocation intermediate or ${\beta}$-addition of ${\alpha},{\beta}$-unsaturated carbonyl compounds. The starting 2-alkenyl pyrroles were synthesized by Aldol condensation of 2-formylpyrrole with active methylene compounds such as nitromethane, diethylmalonate and malononitrile. Attempted ‘2+2' condensation of meso-diethylmalonyldipyrromethane, meso-(p-tolyl)dipyrromethane and p-tolualdehyde afforded three different porphyrins 12, 13 and 14 in reasonable yields. On the other hand, meso-(nitromethyl)dipyrromethane with p-(tbutyl) benzaldehyde resulted in the formation of three different porphyrins such as 5,15-dicyano-10,20-diarylporphyrin (16), 5-cyano-15-formyl-10,20-diarylporphyrin (17) and 5,15-diformyl-10,20-diarylporphyrin (18) in low yields. Conversion of nitromethyl groups to nitrile and (or) formyl group was observed under the porphyrin forming conditions.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.12
• /
• pp.4109-4116
• /
• 2012

An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxy-phenylthiourea resin 3. The resin-bound 2-hydroxyphenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane ($CH_2Cl_2$).

• Bulletin of the Korean Chemical Society
• /
• v.13 no.2
• /
• pp.166-172
• /
• 1992

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethoxyalkyl)phthalimides(alkyl=E thyl, n-propyl, n-butyl, n-pentyl, and n-octyl). Photocyclizations occur in methanol in high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from oxygen in the $\alpha-silylmethoxy$ groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate $\alpha-silylmethoxy$ cation radicals and cyclization by radical coupling are proposed. In contrast, photoreaction of N-(trimethylsilylmethoxyethyl) phthalimide in acetone follows different reaction routes to produce two cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon $\alpha$ to silicon and oxygen atoms via triplet carbonyl hydrogen abstraction triplet carbonyl silyl group abstraction pathways. The normal singlet SET pathway dominates these triplet processes for photoreaction of this substance in methanol. The efficient and regioselective cyclization reactions observed for photolysis in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• The Korean Journal of Pesticide Science
• /
• v.8 no.4
• /
• pp.258-264
• /
• 2004

The pyrazole family was discovered as effective insecticides/acaricides, and fenpyroximate and tebufenpyrad were introduced in the market. In this study, new series of pyrazole oxime ethers were designed and synthesized. The pyrazolone 1 was prepared by the condensation of ethyl acetoacetate with methylhydrazine, and then subsequently subjected to the Vilsmeier-Haack chloroformylation yielding 4-formyl-5-chloro-pyrazole 2. The nucleophilic aromatic substitution of 2 generally allowed the introduction of a wide range of heterocycles into the pyrazole ring. The resulting pyrazole aldehydes 3a-i were readily converted to the corresponding pyrazole oxime derivatives 4a-i, and subsequently to 5-substituted pyrazole oxime ether derivatives 6a-i. The screening assay results clearly show that the activities of 6d were comparable to those of fenpyroximate (6a) against BPH, DBM, and TSSM. It indicates that 6d has a potential to be developed as an insecticidal agent.

• Environmental Analysis Health and Toxicology
• /
• v.13 no.3_4
• /
• pp.55-61
• /
• 1998

Glutathione-S-transferases (GSTs) detoxify electrophilic xenobiotics and reactive metabolites. Recently benzene-fused heterocycles have been shown to increase the total amount of hepatic GSTs in rats. Primarily this study aimed to determine the induction of GSTs by benzoazoles (BAs) including benzoxazole (BX), 2-methylbenzoxazole (M-BX), 2,5-dimethyl benzoxazole (D-BX), benzothiazole (BT), aminobenzothiazole (A-BT) and 2-mercaptobenzothiazole (M-BT) in rats. Hepatic cytosol and poly(A)$^+$ mRNA were prepared from rats after oral administration of BX, BT, M-BX, D-BX, A-BT and M-BT for 5 consecutive days at doses of 1 mmol/kg. Western immunoblot and northern blot analysis were conducted with rabbit anti-GST Ya, Yb$_1$, Yb$_2$, Yc antibodies and cDNA probes containing = 500 bps in the specific coding regions of Ya, Yb$_1$, Yb$_2$, Yc$_1$, and Yc$_2$, respectively. All BAs increased the amount of enzymes and mRNA levels of GSTs. BT was the most effective inducer of GSTs among the compounds examined in this study. Although A-BT and M-BT, the derivatives of BT, induced GSTs, these chemicals had lesser effect on induction of GSTs than BT. The derivatives of BX also induced less GSTs than the parent compound and the addition of methyl group to the benzene ring of BX reduced the induction of GSTs. BAs had better inductive effects on the class $\alpha$(Ya, Yc) than class $\mu$ GSTs (Yb$_1$, Yb$_2$). BAs enhanced mRNA levels of GSTs in parallel with the protein levels. These results indicate that 1) most of BAs induced various isozymes of GSTs, 2) the induction of GSTs appears to be correlated with the chemical structure of the derivatives, and 3) the expression of GST by BAs is presumably under the transcriptional regulation.

• Journal of the Korean Chemical Society
• /
• v.40 no.7
• /
• pp.526-530
• /
• 1996

3-(N-Alkylamino)-4,5-dihydro-1,2,5-thiadiazole 1,1-dioxides have been prepared by the treatment of 3-imino-1,2,5-thiadiazolidine 1,1-dioxides with alkylamines. The selected spectral properties of these heterocycles are detailed, as well as an X-ray crystallographic structure of a representative member of these compounds. 3-(N-Benzylamino)-4,5-dihydro-4-(4'-methoxyphenyl)-1,2,5-thiadiazole 1,1-dioxide crystallyzes in space group $P2_1a$, monoclinic, with $a=22.512(3)(1)\AA$, $b=9.831(2)\AA$, $c=7.194(4)\AA$, $\beta=96.65(2)$, and Z=4.