천식치료제 개발을 위한 benzoxazole과 pyridinothiazole 유도체의 합성 및 5-lipoxygenase 저해작용 평가

Abstract

인간에 존재하는 lipoxygenase는 5,12 그리고 15-lipoxygenase가 있다. 이 중 5-lipoxygenase는 가장 널리 알려져 있고, 염증성 질환이나 알러지성 질환에 중요한 매개체인 leukotriene의 생합성 과정에 관여하기 때문에 중요하게 여겨지고 있다. 본 연구에서는 5-lipoxygenase 저해제로서 천식치료제로 사용되는 Zileuton 구조를 모델로 하여 pyridinothiazole 과 benzoxazole 유도체를 합성하고, LTC4 저해능력을 평가하는 것을 목표로 하였다. Pyridinothiazole은 우선 3-nitro-2-hydroxypyridine을 2-amino-3-hydroxypiridine(a)으로 환원시킨 후, 다양한 isothiocyanate와 반응시켜 N-(2-Hydroxypyridino)-N-(Substituted) thiourea(a1~a7)를 합성하였다.. Thiazole ring으로 cycliztion하기 위해 thiourea를 TFA에서 24시간 동안 가열 환류 하였고, 관크로마토그래피를 통해 분리해내어 2-substituted aminopyridinothiazole (A1~A7)을 얻을 수 있었다. Benzoxazole 유도체들은 두 가지 방법으로 합성할 수 있었다. 우선, 4-methoxy-2-nitrophenol과 4-methyl-2-aminophenol을 환원시켜 얻은 2-amino-4-methoxyphenol(b) 과 2-amino-4-methyl phenol(c)을 isothiocyanate과 반응시켰다. N-(2-Hydroxy-5-methoxy phenyl)-N-(substituted) thiourea (b1~b8) 과 N-(2-Hydroxy-5-methylphenyl)-N-(substituted) thiourea(c1~c12) 을 합성한 후, 산화제를 이용하여 8-Methoxy-2-[N-(substituted)] aminobenzoxazole (B1~B8) 과 8-Methyl-2-[N`-(substituted)] aminobenzoxazole (C1~ C12) 합성하였다. 다른 benzoxazole은 benzoxazole amide 유도체들로서 amide를 carbondisulfide, iodomethane, sodium hydride를 사용하여 실온에서 교반하여 N-(bis-methysulfanylmethylene) amide (d,e,f,g,h,i) 화합물을 합성하였다. 여러 치환체를 가진 amide와 다양한N-(bis-methysulfanylmethylene) amide를 반응시켜 32종의 benzoxazole amide 유도체들을 합성할 수 있었다. 위의 합성방법으로 총 59종의 유도체를 합성하였고 세포수준에서의 생리활성 테스트를 실시하였다. 테스트 결과 nanomole 범위의 in vitro 활성을 갖는 화합물 6종을 선별할 수 있었다. 이 중 E2, G3 는 대량 합성 진행 중이고, A1, A4, A7, C3 대량 합성하여 독성테스트와 in vivo 테스트를 진행하고 있다. 이런 결과를 바탕으로 위 화합물들의 구조와 활성에 대한 관계를 더 연구하여 더욱 좋은 활성의 유도체를 중심으로 많은 화합물들을 다양하게 만들어 나간다면, 더 효과가 뛰어난 천식 치료제가 개발 될 것이다.;The enzyme 5-lipoxygenase is a key target in the effort to discover drugs which inhibit the pathophysiology associated with the formation of leukotrienes. Design of Iron-chelator inhibitors, widely described by hydroxamic acid, one of the most powerful metal ligand groups and N-hydroxyurea derivatives, has been more fruitful. Zileuton was the first 5-LOX inhibitor brought to market for the treatment of bronchial asthma. This research has focused on the discovery of direct enzyme inhibitors of 5-lipoxygenase. The design of 5-LOX inhibitor was discovered with modification of Zieuton. Pyridinothiazole and benxoxazole were designed as 5-LOX inhibitor and synthesised about 60 derivatives. Pyridinothiazole and aminobenzoxazole were synthesised with cycliztion of thiouea. Amino-hydroxypyridine was reacted with several substituted isothiocyanates to yield thioureas and pyridinothiazole was synthesised in acid solvent. As same method, aminophenol was reacted with isothiocyanates to give thiourea. Then thiourea was cylized with oxidant to synthesize aminobenzoxazole. Benzoxazole amides were prepared from the commercial amide in 2 steps. The commercial amide was reacted with carbon disulfide, iodomethane and sodium hydride to yield the dimethyl carbonimidodithioate, which was cyclized to benzoxazoles through refluxing in DMF. Except 9 compounds, 50 compounds were assayed in LTC4 inhibition test. Most of pyridinothiazole derivatives showed high inhibition ability and A1, A4, A7 were chosen for a large-scale synthesis. Benoxazole derivatives also showed good biological activities as 5-LOX inhibitor. Among the compounds, C3 was chosen and was synthesize on a large scale. Compounds A1, A4, A7, C3 were evaluating toxicology test and in vivo test.