HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• formation, essential for the GBB-3CR mechanism. Moderate yields were obtained with the use of 2-aminothiazole derivatives (4yy–aaa). These lower yields did not change using MeOH as a solvent or increasing the amount of HPW used. The use of aliphatic aldehydes in the GBB multicomponent reaction for the

• (a). Substrate scope of the HPW-catalyzed GBB reactions using a range of aromatic/heteroaromatic aldehydes. Reaction conditions: 2-aminopyridine/2-aminothiazole (0.50 mmol), aromatic/heteroaromatic aldehyde (0.50 mmol), isocyanide (0.50 mmol), and HPW (0.01 mmol, 2 mol %) in EtOH (0.5 mL), under μw

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• with thioureas [42]. However, the reported method only tolerates aromatic and aliphatic ketones; the active methylene ketones were not suitable. Given that amino acids have been reported to work as green organocatalysts for the synthesis of 2-aminothiazole heterocycles [43][44]. We herein report a ᴅʟ

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• -carbothioamides 1i–l, the reaction of the primary thioamide of 2-aminothiazole-4-carboxyamide (1m) with sulfonyl azides 2a,c is succesful in n-propanol at reflux temperature, to afford N-sulfonyl amidines 3ab and 3ac bearing a 2-aminothiazole ring in very good yields (Scheme 4). 3-Methyl-5-phenyl-isoxazole-4-N

• . The 1-alkyltriazole thioamides are the most active in the solvent-free method due to their low melting points and good solubility in alkyl- and arylsulfonyl azides. Conversely, thioamides containing 5-arylamino-1,2,3-triazole and 2-aminothiazole rings are not soluble in sulfonyl azides and could be

• -triazole-4-carbothioamides 1i–l with azides 2a,c–f. Synthesis of 2-aminothiazole-4-N-sulfonyl amidines. Synthesis of N-sulfonyl amidines of isoxazolylcarboxylic acid. Synthesis of bis(sulfonyl amidines) 3aj–an. Plausible mechanism for the reaction of heterocyclic thioamides with sulfonyl azides

Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate

• Mysore Bhyrappa Harisha,
• Pandi Dhanalakshmi,
• Rajendran Suresh,
• Raju Ranjith Kumar and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2020, 16, 2108–2118, doi:10.3762/bjoc.16.178

• existing alkaloids and a number of pharmaceutically active compounds [51][52][53]. 2-Aminothiazole has a thiourea-like character with a tendency to modulate promiscuously multiple biological targets. Thiazole derivatives also exhibit a broad spectrum of biological activities including antiviral, antiprion

• give the intermediate A which undergoes homolytic cleavage yielding B. Subsequent cyclisation results in the oxazole ring. During these optimization trials, it was interesting to note the formation of 2-aminothiazole, when ferric chloride was employed along with thiocyanate (Table 1, entry 3). There is

• thiocyanate (2) as a representative model system. To optimize the best reaction condition, we began this study by performing the reaction with ferric chloride in acetonitrile at 80 °C for 6 h (Table 2, entry 1). This reaction has led to the exclusive formation of 4,5-disubstituted 2-aminothiazole 4d. The

N-Propargylamines: versatile building blocks in the construction of thiazole cores

• S. Arshadi,
• E. Vessally,
• L. Edjlali,
• R. Hosseinzadeh-Khanmiri and
• E. Ghorbani-Kalhor

Beilstein J. Org. Chem. 2017, 13, 625–638, doi:10.3762/bjoc.13.61

• to diethyl 3-aminoprop-1-ynylphosphonate salts 18 leading to 5-diethyl methylphosphonate-substituted 2-aminothiazoles 19 in good yields (Scheme 4b) [86]. An interesting approach towards the synthesis of 2-aminothiazole derivatives by treatment of N-propargylamines with isothiocyanates in the presence

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• the 2-aminothiazole core of fanetizole (87). Due to preceding studies on the use of ammonia gas in this tube-in-tube system including in-line titrations only a minimal excess of gas (1.06 equivalents) was necessary to obtain complete conversion in the initial reaction subsequently allowing safe scale

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• will be less protonated at physiological pH than the aminopyridine ring, and so the molecule will carry a lower net charge. This could lead to an increased ability to cross the blood-brain barrier thereby increasing the in vivo potency of these compounds. The 2-aminothiazole-based compound was less

• potent than the 2-aminopyridine-based analogue. 4-Aminothiazoles were unstable in water, undergoing tautomerization and hydrolysis to give inactive thiazolones. Keywords: 2-aminothiazole; 4-aminothiazole; nitric oxide synthase inhibitor; nNOS; Introduction Neuronal nitric oxide synthase (nNOS) is the

• diastereomers was formed, but both were oxidized to α-bromoketone 12. Condensation with thiourea gave the 2-aminothiazole (13). Diprotection of the amine with Boc groups and deprotection of the TBS ether gave trans-alcohol 15. A Mitsunobu reaction was used to install a nitrogen atom in the form of a phthalimide