Radiation-protective Agents. II. The Transformation of 2-(2-Aminoethyl)thiopseudoureas to 2-Amino-2-thiazolines
作者:Tohru Hino、Katsuko Tana-ami、Kazuko Yamada、Sanya Akaboshi
DOI:10.1248/cpb.14.1201
日期:——
The cyclization of N-substituted 2-(2-aminoethyl)thiopseudoureas (AETs) to 2-aminothiazolines (2-Ats) was investigated. The AETs (I, II and III) having a substituent at the amino nitrogen afforded a simple 3-substituted 2-Ats. The phenyl derivative was cyclized easier than the corresponding methyl derivative. The AETs (VII and VIII) having a substituent at the nitrogen atom of the thiourea, however, afforded the mixture of products, IV (2-aminothiazoline) and a 2-(substituted-amino)-2-thiazoline. 2-Aminothiazoline (IV) was the main product in the case of methyl derivative (VII), while substituted 2-AT was the main product in the case of phenyl derivative (VIII). The AETs (XI and XII) in which the both nitrogens of thiourea were linked with two or three methylenes afforded 2-ATs (XII and XIV) without removal of an amine, and the free bases of these 2-ATs were unstable and underwent a rearrangement to give 2-(2-mercaptoethylamino)imidazoline or-tetrahydropyrimidine.
对N取代的2-(2-氨基乙基)硫伪尿素(AETs)环化生成2-氨基噻唑啉(2-Ats)进行了研究。具有氨基氮取代基的AETs(I、II和III)生成简单的3-取代2-Ats。苯基衍生物的环化比相应的甲基衍生物更容易。然而,氨基硫尿素氮原子上有取代基的AETs(VII和VIII)则产生了产品混合物IV(2-氨基噻唑啉)和一种2-(取代氨基)-2-噻唑啉。在甲基衍生物(VII)的情况下,2-氨基噻唑啉(IV)是主要产品,而在苯基衍生物(VIII)的情况下,取代2-AT是主要产品。在两氮原子均与两个或三个亚甲基连结的AETs(XI和XII)中,则生成2-ATs(XII和XIV),且未去除氨基,这些2-ATs的游离碱不稳定,发生重排生成2-(2-巯基乙基氨基)咪唑啉或四氢吡啶。