Ring Transformations via Bridged 1,3-Dicarbonyl Heteroanalogs; Part II.1. Synthesis of 4-(ω-Aminoalkyl)-thiazoles by a Novel Ring Transformation Reaction of Semicyclic Thioacylamidines with Acidic Methyl Halides
Ring Transformations via Bridged 1,3-Dicarbonyl Heteroanalogs; Part II.<sup>1</sup>. Synthesis of 4-(ω-Aminoalkyl)-thiazoles by a Novel Ring Transformation Reaction of Semicyclic Thioacylamidines with Acidic Methyl Halides
作者:Jürgen Liebscher、Michael Pätzel、Ute Bechstein
DOI:10.1055/s-1989-27452
日期:——
Semicyclic N′-(thioacyl)amidines 1 react with acidic methyl halides 2 as C-synthons via S-alkylation and cyclization to give 4-(Ï-aminoalkyl)-thiazole hydrohalides 5. In this transformation, the thiazole ring is formed while the initial lactam ring is opened. In contrast, semicyclic N-(thioacyl)amidines 1 react with α-haloketones as C-C building blocks in a Hantzsch-type thiazole synthesis affording semicyclic 2-amidinothiazoles 6 or thiazolium salt 7 while the starting lactamimine ring is retained.
Synthesis of 4-(ω-Aminoalkyl)- or 4-(ω-Lactamiminoalkyl)thiazoles by Ring Chain Transformation of Isothioureas with Lactam Derivatives
作者:Ute Radics、Jürgen Liebscher、Michael Pätzel
DOI:10.1055/s-1992-26197
日期:——
CH-Acidic isothioureas 1 react with lactam acetals 2 at the unsubstituted N-atom as well as at the acidic S-methylene group giving 4-(Ï-aminoalkyl)thiazoles 6. The latter are further transformed to 4-(Ï-lactamiminoalkyl)thiazoles 8, if lactim ethers 3 are used in reactions with isothioureas 1.