• Archives of Pharmacal Research
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• v.23 no.2
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• pp.104-111
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• 2000

Stereochemical isomers with hydroxy groups were synthesized by reacting 2-(dimethoxy-methyl)cyclohexanone with propargylmagnesium bromide. The stereo chemical structures were identified by NMR spectral interpretation and the geometry optimization. To assist the NMR interpretation, geometry optimization based on semi-empirical AM1 and PM3 methods was applied. Throughout this study, the structures of the two isomers were all determined and $^{1}H$ and $^{13}C$ NMR spectra were fully assigned. It was proven that the less polar isomer is an axial alcohol and the more polar one is an equatorial alcohol.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.168-172
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• 1987

Methods were developed to synthesize optically active mercaptoglycerol from optically active isopropylidene glycerols. 1,2-Isopropylideneglycerol was tosylated and the tosyl group displaced with thiolacetate. Base hydrolysis and oxidation gave 1,1'-dithiobis-2,3-isopropylidene-2,3-propanediol. This compound could be used as a source of mercaptoglycerol, or reacted with 1-decenyl lithium to form cis-1-S-dec-1'enyl-2,3-isopropylidene-1-mercapto-2,3-propanediol. The latter is a stereospecific synthetic route to cis-alkenyl thioethers of protected mercaptoglycerol, and it may be useful for the preparation of a thioplasmalogen substrate for plasmalogenase.

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.786-790
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• 1996

A novel optically active tetraamine ligand possessing four asymmetric centers, N,N'-bis(2(S)-aminopropyl)-1(R),2(R)-trans-1,2-diaminocyclohexane (SRRS-apchxn) and its cobalt(Ⅲ) complexes, [Co(SRRS-apchxn)X2]n+ (X=Cl-, H2O, X2=CO32-) have been synthesized. This ligand has coordinated stereospecifically to the cobalt(Ⅲ) ion to give only the Λ-uns-cis-(SS) isomer. A trans dichloro complex has been obtained via the stereospecific isomerization of Λ-uns-cis-(SS)-[Co(SRRS-apchxn)Cl2]+ to trans-(SS)-[Co(SRRS-apchxn) Cl2]+ in CH3OH-HCl medium. Ligand and complexes have been characterized by electronic absorption, 1H NMR, CD spectra, and also by elemental analysis. It is of interest that this is one of the few CoⅢ(N4)X2 type complex preparations, which produces such an uns-cis isomer with stereospecificity.

• Bulletin of the Korean Chemical Society
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• v.6 no.6
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• pp.369-374
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• 1985

A new flexible quadridentate ligand, N,N'-dimethylethylenediamine-N,N'-di-${\alpha}$-propionic acid (dmedpa) has been synthesized, and diammine and ethylenediamine cobalt(III) complexes of dmedpa, $[Co(dmedpa)(NH_3)_2]^+$ and $[Co(dmedpa(en)]^+,$ have been prepared. Only s-cis isomer has been yielede. A known N,N'-dimethylethylediamine-N,N'-diacetic acid (dmedda) has also been prepared. Dichloro cobalt(III) complexes of both dmedda and dmedpa have been prepared. Only the s-cis isomer has been yielded in the $[Co(dmedda)Cl_2]^-$ complex, while only the uns-cis isomer has been obtained for the $[Co(dmedpa)Cl_2]^-$ complex.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.379-381
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• 1988

Racemic nuciferal(1) and nuciferol(2), the terpenic natural perfumeries, have been synthesized by a simple procedure. The benzylic halide 6; 1-(1-chloroethyl)-4-methylbenzene, was prepared by converting p-tolualdehyde(4) into 1-(p-tolyl)-1-ethanol(5), followed by convertion of 5 into corresponding chloride. The Grignard reagent of 6 was reacted with the bromoacetal 7, 2-(2-bromoethyl)-1,3-dioxolane, to give a crosscoupling product 8, which was hydrolysed to 4-(p-tolyl)-pentanal (9). The Wittig reaction of isopropylide 10 with 9 yielded arcurcumen(11). The stereospecific allylic oxidation of the gem-dimethyl olefin 11 with selenium dioxide afforded a trans-aldehyde, (${\pm}$)-1, which was reduced to corresponding alcohol, (${\pm}$)-2.

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.428-432
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• 1996

Amino acid cobalt(Ⅲ) complexes of 1,3-diminopropane-N,N'-di-α-(β-methyl)-pentanoic acid (H2dpdmp), uns-cis-[Co(dpdmp)(aa)] (aa=glycine, S-alanine, R-aspartic acid, sarcosine) have been prepared from the reaction between the uns-cis-[Co(dpdmp)Cl2]- complex and the corresponding amino acid. In the reaction with the uns-cis-[Co(dpdmp)Cl2]- complex, glycine and S-alanine have yielded both merridional and facial isomers, while R-aspartic acid and sarcosine, only merridional isomers. The stereospecific substitution reaction of R-aspartic acid to racemic uns-cis-[Co(dpdmp)Cl2]- complex has yielded two merridional diastereomers; ΛR-uns-cis- and ΛR-uns-cis-[Co(dpdmp)(R-asp)]. It is of interest to note that this is one of the few CoⅢ(ONNO)(aa) type complex preparations, which gives only one isomer with stereospecificity. On the other hand, two merridional products obtained from the reaction of sarcosine with racemic uns-cis-[Co(dpdmp)Cl2]- are turned out to be mixtures of optical isomers.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.472-477
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• 1986

The reaction of (E)- or (Z)-1-alkenylmercuric chlorides with acrylic acid derivatives in the presence of 10 mol% of lithium trichloropalladate ($LiPdCl_3$) and an equimolar amount of cupric chloride, as a reoxidant for the palladium, in acetonitrile at room temperature gave the corresponding (E,E)- or (E,Z)-2,4-dienoic acid derivatives stereospecifically in moderate to good yields. The reaction of (E)- or (Z)-3-chloromercuripropenoic acid with olefins under the reaction condintion described above similarly gave good yields of (E,E)- or (Z,E)-2,4-dienoic acids stereospecifically. A side reaction, the homocoupling of alkenylmercuric chlorides, could be minimized by employing the condition described above. However, in the reaction of 3-chloromercuripropenoic acid with olefins under the present condition, the homocoupled side reaction product was not produced.

• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.191-193
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• 1984

6, 6-Diiodopenicillanic acid was prepared from 6-aminopenicillanic acid using iodine-sodium iodide systems in good yield (60%). Enolates derived from 6-chloro-6-iodo-, 6,6-diiodo-penicillanate have been generated in situ by a metal-halogen exchange process at -$78^{\circ}C$ using methylmangnesium iodide and reacted with acetaldehyde to yield aldols. As the size of remaining halogen atom increases, the proportion of ${\beta}$-face attack was increased. In the case of 6,6-diiodopenicillanate, only ${\beta}$-face attack was observed yielding a single isomer (6S, 8R).

• Bulletin of the Korean Chemical Society
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• v.5 no.6
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• pp.237-240
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• 1984

2,2'-Diaminobiphenyl platinum (II) complexes of optically active trans-1,2-diaminocyclohexane and 1,2-diaminopropane, [Pt(S,S-chxn)(dabp)]Cl2, [Pt(R,R-chxn)(dabp)]$C_{12}$, [Pt(S-pn)(dabp)]$C_{l2}$, and [Pt(R-pn)(dabp)]Cl2, where S,S-chxn and R,R-chxn are, respectively, S and R isomers of trans-1,2-diaminocyclohexane, and S-pn and R-pn are, respectively, S and R isomers of 1,2-diaminopropane, and dabp the 2,2'-diaminobipheny, have been prepared. The dabp ligand has been found to take the $=delta$ conformation in the S,S-chxn and S-pn platinum (II) complexes, while it takes the $\lambda$ conformation in the R,R-chxn and R-pn platinum (II) complexes.

• Journal of the Korean Chemical Society
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• v.41 no.9
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• pp.465-470
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• 1997

A chiral pentadentate ligand, 1,9-bis(S)-prolyl-1,9-dioxo-2,5,8-triaza-nonane, (S,S-prochen) which shows the stereospecific reaction was synthesized from the reaction of S-proline and diethylenetriamine (dien). The red-violet $[Co(SS-prodien)H_2O]ClO_4$ was prepared by the oxidation of the aqueous solution dissolving $CoCl_2{\cdot}6H_2O$ and S,S-prodien. Elemental analysis, electronic absorption spectroscopy, and $^{13}C-NMR$ spectroscopy suggest that the geometrical structure of the Co(III) complex to be an ${\alpha}{\beta}$ (ffm) form, where the dien moiety of the ligand chelates the metal center to comprise a facial isomer, and an aqua ligand coordinates a cis site to the secondary nitrogens of the dien. Based upon the CD spectroscopic analysis, it seems that the absolute configuration of the ${\alpha}{\beta}$(ffm)-$[Co(SS-prodien)H_2O]ClO_4$ has the ${\Lambda}$-form.