Synthesis of methyl 2-aryl-5-chlorosulfonyl-1,3-oxazole-4-carboxylates and their reactions with amines and amidines

Abstract

Previously unknown methyl 2-aryl-5-chlorosulfonyl-1,3-oxazole-4-carboxylates have been synthesized. Their reactions with amines and amidines have yielded the corresponding sulfonamides and 6H,7H-[1,3]oxazolo-[5,4-d]pyrimidin-7-ones.

Dependence of the anticancer activity of 1,3‐oxazole derivatives on the donor/acceptor nature of his substitues

“…Methyl 5‐((5‐amino‐3‐1 H ‐pyrazol‐1‐yl)sulfonyl)‐1,3‐oxazole‐4‐carboxylates 24, 25 were prepared by refluxing of methyl 5‐chlorosulfonyl‐2‐phenyl‐1,3‐oxazole‐4‐carboxylate ( 23 ) with 3‐methyl‐ or 3‐phenyl‐1 H ‐pyrazol‐5‐amine and triethylamine in dioxane (Scheme ) …”

“…4‐Cyano‐2‐(4‐methylphenyl)‐1,3‐oxazole‐5‐sulfonyl chloride ( 17 ) and 4‐cyano‐2‐phenyl‐1,3‐oxazole‐5‐sulfonyl chloride ( 18 ) were synthesized previously from appropriate enamide 1 or 2 . Methyl 5‐chlorosulfonyl‐2‐phenyl‐1,3‐oxazole‐4‐carboxylate ( 24 ) have been synthesized by the method described in the literature …”

“…Reagents and conditions: (a) 2-(methylamino)ethanol, Et 3 N, THF, rt, 12 hours; (b) 2-(4-chlorophenyl)-2-piperidin-1-ylethanamine, Et 3 N, THF, rt, 12 hours; (c) arenethiol, Et 3 N, acetonitrile, rt, 8 hours; Ag 2 CO 3 , acetonitrile, reflux, 8 to 10 hours; (d) H 2 O 2 , AcOH, reflux, 1 hour of methyl 5-chlorosulfonyl-2-phenyl-1,3-oxazole-4-carboxylate (23) with 3-methyl-or 3-phenyl-1H-pyrazol-5amine and triethylamine in dioxane (Scheme 3). [48] Data of synthesized novel 1,3-oxazole derivatives are presented in Section 4. NMR ( 1 H and 13 C NMR), chromato-mass, and elemental analysis confirm reliably the structure of the obtained compounds.…”

Synthesis and Biological Activity of Oxazolopyrimidines

“…Treatment with triphenylphosphine, hexachloroethane and triethylamine produced iminophosphorane 184 in good yield. [40,41] The Cornforth rearrangement is a reaction which is specific for 4-acyloxazoles. Annulation of pyrimidine rings to 4-carboxy-5-aminooxazoles using a variety of one-carbon synthons.…”

“…When these hemi-aminals were heated to 110-140°C, ring closure to the oxazolopyrimidines 10 was observed, but also ring opening to the ester and the amide. [40,41] Eur. The desired oxazolo[4,5-d]pyrimidines 10 were still only obtained in low yields.…”