PDF icon Download PDF
Synlett 2003(13): 1967-1968  
DOI: 10.1055/s-2003-42050
LETTER
© Georg Thieme Verlag Stuttgart · New York

Process Development of 1,2-Benzisothiazolin-3(2H)-one by Replacing of the Toxic Materials

Chun Keun Jinb, Jung-Kyen Moon, Woo Song Lee*a, Keun Soo Nam*b
a Korea Research Institute of Bioscience and Biotechnology, 52 Oun, Yusong, Daejeon 305-333, Republic of Korea
Fax: +82(42)8612675; e-Mail: wslee@kribb.re.kr;
b NeoNal Company, Ltd., Pyungchon, Seo-ku, Daejeon 302-070, Republic of Korea
Further Information

Publication History

Received 16 July 2003
Publication Date:
08 October 2003 (online)

   Permissions and Reprints All articles of this category
Preview

Abstract

1,2-Benzisothiazolin-3(2H)-one (2) was synthesized by 2,2′-dithiodibenzoic acid (1) with acetamide or urea in high yield via one-pot amidation-cyclization process.

Key words

1,2-benzisothiazolin-3(2H)-one - amidation-cyclization - one-pot-procedure

1

Dozen Tech Company, Ltd., 955-1 Dohwa, 402-060 Incheon, Republic of Korea.

7

Procedure of 1,2-Benzisothiazolin-3(2H)-one (2).11 To a 1000 L reactor was equipped with a mechanical stirrer, a thermometer, and a condenser, 28% NaOMe (52.1 kg) in MeOH solution was added for 10 min and distilled under reduced pressure (60 °C/750 mmHg, 2.5 h) to get the MeOH (15 L). In order to get rid of the extra MeOH, toluene (100 kg) was added and distilled to get the MeOH (15 L) for 1.5 h. Acetamide (16 kg) was added and refluxed for 1 h, then, the reactor was cooled to 25 °C. Dimethyl 2,2′-dithiodibenzoate (3) (23.5 kg) was slowly added at 25 °C, the reaction mixture was refluxed at 80 °C for 2 h, cooled to <20 °C, added H2O (150 L), stirred for 30 min, filtered, and separated to give aqueous layer and toluene layer (70 kg). The aqueous layer was added 28% H2O2 (12 kg) dropwisely for 30 min (increasing temperature to 50-55 °C). The basic active carbon (3 kg) and Al2O3 (DN-3) (300 g) were added, stirred for 1 h at 25 °C, and filtered. Addition of conc. HCl (20 kg, 35% solution, and pH = 3-4) was added dropwisely to precipitate the wet 1,2-benzisothiazolin-3(2H)-one (2), which was filtered, washed with cold water (30 L), and dried on air to afford 2 (18 kg, 85%) as off-white solid (MeOH), mp 157-158 °C (lit. [12] mp 158-159 °C).
IR (KBr): 3420, 3056, 2911, 1630 cm-1.
1H NMR (300 MHz, CDCl3): δ = 1.37 (s, 9 H), 5.70 (br s,
1 H), 6.53 (d, 1 H, J = 1.7 Hz), 7.37-7.62 (m, 5 H), 11.64
(br s, 1 H).
Anal. Calcd for C7H5NOS: C, 55.61; H, 3.33; N, 9.26; S, 21.21. Found: C, 55.45; H, 3.50; N, 9.52; S, 21.08.

8

The purity of 2 was verified by HPLC analysis employing the Shimadzu LC-6A instrument equipped with an SPD-6A UV detector as follows: Compound 2: Detector, Youngjin M 720; pump, waters 510; integrator, waters 746, Youngjin D 520B; wave length, UV-225 nm, column, ODS-2 (250 nm × 4.6Ψ); end time, 30 min; eluent MeOH-H2O (35:65, v/v); flow rate, 1.0 mL/min; attenuation, 1.28; chart speed, 0.5.
Procedure is as follows: 10 mg standard 1,2-benzisothiazolin-3(2H)-one (BIT) (2) is weighed to 0.1 mg accuracy in 100 mL flask and added 10 mL of 0.5 (w/v)% methylbenzoate/MeOH. The flask is filled up with HPLC eluent to 100 mL. Compound 2 is prepared as same as standard BIT. At least three HPLC tests are conducted until constant areas are obtained. Compound 2 assay is calculated from the HPLC area in proportion to standard BIT. Calculation was conducted as follows: Compound 2 assay = (the area of compound 2 ÷ the area of methylbenzoate)/(the area of standard BIT ÷ the area of methylbenzoate) × 100.