Dai-Il Jung

Improved production of curdlan with concentrated cells ofAgrobacterium sp.

The addition of a limited concentration of yeast extract to a minimal salt medium (MSM) enhanced cell growth and increased the production of curdlan whereas nitrogenlimitation was found to be essential for the higher production of curdlan byAgrobacterium sp. ATCC 31749. As the amount of the inoculum increased, the cell growth as well as the production of curdlan also increased in the MSM without a nitrogen source. The cell growth and production of curdlan increased as the initial pH of the medium decreased as low as 5.0. The conversion rate and concentration of curdlan from 2% (w/v) glucose in the MSM with concentrated cells under nitrogen deletion was 67% and 13.4 g/L, respectively. The highest conversion rate of curdlan under the conditions optimized in this study was 71% when the glucose concentration was 1% (w/v).

SYNTHESIS OF 2,4-DISUBSTITUTED NORTROPINONE DERIVATIVES BY ALDOL CONDENSATION

2,4-Disubstituted nortropinone derivatives 2, with anticipated anticonvulsant activity, were synthesized by the reaction of N-substituted nortropinones, ethanol, 5N-NaOH, and aromatic aldehydes (R1CHO).

Synthesis of the New Saccharin Derivatives Containing Imidazolidine-2,4,5-trione or 2-Thio-imidazolidine-4, 5-dione Group

Saccharin derivatives were synthesized by means of 4 reaction steps involved the reaction of 1-methylurea (or 1-methylthiourea) and oxalyl chloride. 1-Alkyl(or phenyl)-3-(1,1,3-trioxo-1,3-dihydro-1 -benzo[d]isothiazol-2-ylmethyl)-imidazolidine-2,4,5-trione 5 and 1-alkyl(or phenyl)-2-thioxo- 3-(1,1,3-trioxo-1,3-dihydro-1 -benzo-[d]isothiazol-2-ylmethyl)-imidazolidine-4,5-dione 12 were obtained by means of 4 reaction steps involved the reaction of 1-methyl-urea(or 1-methylthiourea) and oxalyl chloride.

Synthesis and Activity Evaluation of Imidazolidinetrionylsaccharin Derivatives

1-Methyl-3-(1,1,3-trioxo-1,3-dihydro-1λ-benzo[d]isothiazol-2-ylmethyl)-imidazolidine-2,4,5-triones 5a, 1-ethy1-3-(1,1,3-trioxo-1,3-dihydro-lλ/-benzo[d]isothiazol-2-ylmethyl)-imidazolidine-2,4,5-triones 5b 1-phenyl-3-(1,1,3-trioxo-1,3-dihydro-1λ-benzo [d]isothiazol-2-ylmethyl)-imidazolidine-2,4,5-triones 5c were obtained by means of 4 reaction steps involved the reaction of 1-methyl-urea and oxalyl chloride. Biological tests(Plant Response Screening Result, Insect Primary Screening Result and Fungicide Primary Screening Result) of synthesized sacccarin derivatives were executed.