Reaction between alkyl isocyanides and dibenzoylacetylene in the presence of strong NH-acids: synthesis of highly functionalized aminofurans

Protonation of the highly reactive 1:1 intermediates produced in the reaction between alkyl isocyanides and dibenzoylacetylene by saccharin, phthalimide, or 4-methyl-5-nitroimidazole, leads to vinylnitrilium cations, which undergo carbon-centered Michael type addition with the conjugate base of the NH-acid to produce highly functionalized aminofuran derivatives.     

Facile One‐Pot Synthesis of 4‐Hydroxy‐2‐methyl‐(2H)‐1,2‐benzothiazine‐3‐sulfonic Acid 1,1‐Dioxide

We report a convenient synthesis of 4‐hydroxy‐2‐methyl‐(2H)‐1,2‐benzothiazine‐3‐sulfonic acid‐1,1‐dioxide (6a) prepared in a novel one‐pot reaction. The synthesis involves two transformations starting from 2‐methyl‐2H‐1,2‐benzothiazin‐4‐(3H)‐one 1,1‐dioxide (7) with an overall yield better than that from the stepwise process, as well as the alternate procedure starting from saccharin (1). One‐pot synthesis of an important intermediate, saccharin‐N‐methane sulfonic acid (4), is also described.     

糖精钠固溶体在玻碳电极上的伏安行为及其应用

在琼脂固溶体电解质和0．1mol／LNaOH-0．1mol／LKCl底液中,研究了糖精钠在玻碳电极上的电化学行为。糖精钠在-1864mV(vs．SCE)产生了二阶微分线性扫描伏安峰,并用红外光谱和紫外光谱对电极产物进行了初步鉴定,提出了糖精钠在玻碳电极上的还原机理。该方法应用于饮料中糖精钠的测定,线性范围为20．0～700．0mg／L;检出限10．0mg／L;其加标回收率和样品测定RSD(n=6)分别为98．2％。102．2％和1．2％～2．8％。     

主成分回归-紫外光度法同时测定甜味剂安赛蜜、阿斯巴甜和糖精

报道了一种快速、简便的同时测定食用甜味剂安赛蜜、阿斯巴甜和糖精的光度法,方法基于在pH=3.25的B-R缓冲溶液中对安赛蜜、阿斯巴甜和糖精三组分混合溶液进行光度测定,所得的重叠波谱数据用主成分回归法(PCR)和偏最小二乘法(PLS)等化学计量学方法进行处理,结果表明主成分回归法(PCR)的预报误差最小.对样品进行测定,获得了较好的定量分析结果.安赛蜜、阿斯巴甜和糖精线性范围分别为1.0～30.00 mg·L-1,1.0～20.0 mg·L-1,1.0～14.0 mg·L-1.