Halogen Reactivities. Certain Heterocyclic Iminohalide Systems¹

Abstract

Pseudo-first order rate constants have been determined for the reactions of 2-bromopyridine (I), 2-bromoquinoline (11), 2-chloroquinoline (111) and 2-chlorothiazole (IV) with piperidine a t various temperatures in the range between 40.00 and 90.00'.The reactions of 2-chloropyrimidine (V) and 2-chlorobenzothiazole (VI) with piperidine have been shown to proceed much more rapidly than the reactions of compounds I to IV, too rapidly, in fact, to permit quantitative rate measurements under similar temperature conditions. Comparison of rate constants calculated a t a common temperature of 50.00' establishes the following order of decreasing activity:

Halo‐ and Nitrothiazoles

“…The nucleophiles used are OH-(32) [the 2-hydroxythiazole can also be obtained by acidic hydrolysis with strong mineral acids (33)], OR-(5, 8,30,34), SR- (8,9,12), ArSH ( 3 3 , and amines (4,7,14,33). Benzamide also reacts with 2-bromothiazole, yielding 2-benzamidothiazole (36).…”

Heteroaryl-Substituted Naphthalenes and Structurally Modified Derivatives: Selective Inhibitors of CYP11B2 for the Treatment of Congestive Heart Failure and Myocardial Fibrosis

“…21,22 The synthesis of the quinoline and quinoxaline analogues 19-21 started from the commercially available hydroxy quino(xa)lines. Treatment with POBr 3 yielded the brominated compounds 20i and 21i, 23 which were consecutively coupled with 3-pyridylboronic acid to give the 3-pyridylquino(xa)lines 19-21.…”

Review of the synthesis and biological activity of thiazoles

“…[19] The cyclization of N-substituted thioureas 9 with halocarbonyl compounds 19 gives 2-monosubstituted aminothiazoles 20 (Scheme 6). [19] N,N-disubstituted thioureas 21 reacted with a-halocarbonyl 14 to yield 2-disubstituted aminothiazoles 22 but in lower yields [20][21][22][23] (30-70%) (Schemes 7 and 8).…”