2-amino-4-methyloxazole

The chlorination of the antibacterial sulfonamide sulfamethoxazole was initiated by N-chlorination of the primary amine. Further reaction of the A,A-dichlorinated compound resulted in the final production of 3-amino-5-methyloxazole and 1,4-benzoquinone-imine (Dodd and Huang 2004). 

Amino-3-methylisoxazole, 1502 2-Amino-4-methyloxazole, 1500 5-Amino-3-methylthio-l,2,4-oxadiazole, 1192 Ammonium A-nitrosophenylaminooxide, 2399 2-Aza-l,3-dioxolanium perchlorate, 0898 Azoformaldoxime, 0815 Bis(l-benzo[d]triazolyl) carbonate, 3598 Bis(l-benzo[d]triazolyl) oxalate, 3629 Bis(trifluoromethyl) nitroxide, 0638 2-/er/-Buty 1-3 -phenyloxaziridine, 3406 Calcium bis(O-hydroxylamide). 3930 Calcium hydroxide O-hydroxylamide, 3929... 

The following standard esterification procedure was applied to /V-benzoylalanine oxalyl chloride was added to a solution of /V-benzoylalanine in anhydrous THF, the mixture was stirred overnight at room temperature, then the solvent and residual traces of oxalyl chloride were evaporated in vacuo. Triethylamine and then methanol were added to the residue at 0°C. On work-up, none of the expected amino acid ester was obtained. The product, isolated in 51% yield, was found to be methyl 2-phenyl-4-methyloxazole-5-carboxylate, and the process was found to be general for a variety of IV-benzoylated a-amino acids. 

See Hydrogen peroxide 2-Amino-4-methyloxazole See related ISOXAZOLES... 

The nonribosomal cyclic peptide leucamide A, 352, was isolated from the marine sponge Leucetta microraphis from the Great Barrier Reef of Australia <2002JOC4989, 2002JOC1636>. It was isolated as the principal active component and found to inhibit the growth of three tumor cell lines (stomach carcinoma, liver carcinoma, liver carcinoma with mutated p53). The compound is composed of seven amino acids and amino-acid-derived residues L-leucine, oxazole, L-alanine, methyloxazole, thiazole, L-valine, and L-proline. 

Reactions of Oxazoles. 2-Amino-4-methyloxazole (359) forms the rearranged hydro-peroxide (360) by the action of hydrogen peroxide. Thermolysis of 2- (3,3-di-methylallyloxy)-4,5-diphenyloxazole yields the oxazolin-2-one (361) with inversion of the allyl group by [ , ] sigmatropic shift irradiation, on the other... 

Khan and Crank found this same pattern of reactivity with condensations of 2-amino-4-methyloxazole 622 (X = 0, R = CH3) with aromatic aldehydes. The authors did not see any evidence for the expected Schiff base. Instead, they isolated products of hydroxymethylation at C(5) 625 in good yield (Scheme 1.172). The structure of 625 (X = O, R = CH3, Ar = 4-CH3OC6H4) was confirmed by X-ray... 

TABLE 1.46. 2-AMINO-5-(HYDROXYMETHYL)-4-METHYLOXAZOLES FROM 2-AMINO-4-METHYLOXAZOLES AND ALDEHYDES-... 

Mekonnen and Crank also found the same reaction dichotomy in Friedel-Crafts reactions of 622 (X = O) with acid chlorides or acid anhydrides. In general, acylation of 622 (X = O, R = CH3) with acetic anhydride or benzoyl chloride/ pyridine afforded the corresponding 2-(acylamino)-4-methyloxazole 630a and 630b (Scheme 1.174). However, low-temperature acetylation or aroylation of 622 (X = O, R = CH3) in the presence of two equivalents of AICI3 produced a 5-acyl-2-amino-4-methyloxazole 631 in low to modest yield. The authors reported that AICI3 was the most effective Lewis acid (SnCLj and TiCL) and that the reaction required two equivalents of Lewis acid. Selected examples are shown in Table 1.48. 

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