Cycloadditions-Eliminierungsreaktionen von Phenylisocyanat mit Oxo-und Thionoderivaten aliphatisch substituierter 5-Imino-1,2,4-dithiazolidine und 3-Thiono-1,2,4-thiadiazolidine (Senf�loxide und Senf�lsulfide)
摘要:
5-Imino-1,2,4-dithiazolidin-3-ones 1 and -3-thiones 3 react with phenylisocyanate to afford 5-imino-1,2,4-thiadiazolidin-3-ones 6. In comparison isomeric 3-thiono-1,2,4-thiadiazolidin-5-ones 2, 5, and -5-thiones 4 yield 3-imino-1,2,4-thiadiazolidin-5-ones 8, 10, and -5-thiones 7. Thermolyses of thiadiazolidines 5 and 10 afford further 1,2,4-thiadiazolidines 9, 11. Compounds 8 - 11 are available also by reaction of substituted guanidines with chlorocarbonyl sulfenylchloride.
A facile high yielding process of guanidines is reported by reaction of amine nucleophiles on the oxidised thioureas in an aqueous medium using the unexploited reagents sodium chlorite and sodium metaperiodate for the oxidation of 1,3-disubstituted thioureas.
In this work, we developed the catalytic guanylation of thiourea using Ru(bpy)3Cl2 as a photocatalyst under irradiation by visible light. The conversion of various thioureas to the corresponding guanidines was achieved using 1–5 mol % of photocatalyst in a mixture of water and ethanol at room temperature. Key benefits of this reaction include the use of photoredox catalyst, low-toxicity solvents/base
Metal-free synthesis of guanidinesfrom thioureas under visible-light irradiation in water was successfully developed. Using 1–5 mol% of inexpensive and commercially available phenazine ethosulfate as a photocatalyst in the presence of 1 wt% cetyltrimethylammonium bromide (CTAB) as surfactant with K2CO3 as an additive base, transformations of a variety of thioureas into the corresponding guanidines under
成功开发了在水中可见光照射下从硫脲中无金属合成胍类化合物。使用 1-5 mol% 廉价且可商购的吩嗪乙硫酸盐作为光催化剂,在 1 wt% 十六烷基三甲基溴化铵 (CTAB) 作为表面活性剂的情况下,以 K 2 CO 3作为添加基,将各种硫脲转化为相应的胍在可见光照射下可获得中高产率。该反应的优点包括使用无金属光催化剂、水作为无毒溶剂以及易于在室温下以开瓶方式操作。
Electrochemical NaI-mediated one-pot synthesis of guanidines from isothiocyanates <i>via</i> tandem addition-guanylation
conditions, we successfully demonstrated the formation of 30 different guanidine compounds, achieving yields ranging from fair to excellent. Furthermore, the synthesis method could be carried out on a gram scale with a good yield. This protocol stands out for its cost-effectiveness, step-economical design, high tolerance towards various functional groups, and environmentally friendly reaction conditions