Synthesis of O-unprotected glycosyl selenoureas. A new access to bicyclic sugar isoureas

β-d-Gluco and mannopyranosyl selenoureas have been prepared by coupling of the corresponding glycosylamines with phenyl isoselenocyanate in aqueous pyridine. Alkyl and aryl isoselenocyanates, and 1,4-phenylene diisoselenocyanate have been obtained from the corresponding formamides with an excess of triphosgene, black selenium and triethylamine. Treatment of the O-unprotected β-d-glucopyranosyl selenourea with aqueous oxygen peroxide afforded a 1,2-trans-fused bicyclic isourea.     

New synthetic approaches to sugar ureas. Access to ureido-β-cyclodextrins

An efficient method for the preparation of urea-bridged cyclodextrins using triphosgene in the isocyanation step in an aqueous two-phase system is reported. Per-O-acetylated glycopyranosylamines and 2-amino-2-deoxy-α and β-d-glucose were also transformed into the corresponding isocyanates using either an aqueous two-phase or an anhydrous dichloromethane medium, and converted in situ into ureas. An alternative method for the preparation of sugar-derived ureas consisting of desulfurization of sugar thioureas with mercury oxide is also presented.     

Chemoselective Hydrogenation of Unsaturated Peroxides

Chemoselective hydrogenation of unsaturated monoperoxyketals provides new methodology for the synthesis of saturated and allyl hydroperoxides.     

Favorski Type Rearrangement in the Lead Tetraacetate Oxidation of Cycloalkanones

The cycloalkanones (1a-lf) have been converted into their corresponding cycloalkane carboxylates (2a-2f) by a lead (IV) acetate promoted rearrangement in presence of perchloric acid in triethyl orthoformate.     

Triphosgene: An Efficient Catalyst for Synthesis of Isothiocyanates

Isothiocyanates are bioactive molecules that show various biological activities such as antifungal and anathematic activities. They play a vital role in the synthesis of various heterocyclic compounds. Various isothiocyanates were prepared in good to high yield using triphosgene.     

Reaction of 3-chloroquinoline-2,4-diones with ethanolamine and rearrangement of the reaction products

The reaction of tertiary α-chloroketones with ethanolamine has not been hitherto described in the literature. Herein, we describe the reaction of tertiary 3-chloroquinoline-2,4-diones with ethanolamine to give novel 3-(2-hydroxyethylamino)quinoline-2,4-diones. These compounds provide 3-(2-oxooxazolidin-3-yl)quinoline-2,4(1H,3H)-diones and new compounds with dimeric character after reaction with triphosgene. Molecular rearrangement proceeds during the reaction of 3-(2-hydroxyethylamino)quinoline-2,4-diones with isocyanic acid. Three types of reaction products arise: 2-(2-hydroxyethyl)imidazo[1,5-c]quinazoline-3,5-diones, 3-(2-hydroxyethyl)-3,3a-dihydro-2H-imidazo[4,5-]quinoline-4(5H)diones and primarily 5-hydroxy-1-(hydroxyethyl)-1′H-spiro[imidazolidine-5,3′-indole]-2,2′-diones. The reaction mechanism and product stereochemistry are discussed. The ¹H, ¹³C and ¹⁵N NMR spectra of the prepared compounds were measured, and all resonances were assigned from appropriate two-dimensional experiments.     

An easy and versatile synthesis of ureas from 2-benzylaminopyrimidine

A general procedure for the easy and versatile synthesis of ureas from 2-benzylaminopyrimidine is described. This methodology involves the preparation of a highly reactive carbamoyl chloride intermediate that can be further reacted with a high variety of different amines, including highly hindered secondary amines and deactivated anilines with excellent yields. Furthermore, this smooth procedure is compatible with a second functionality on the amine.     

新农药研究（Ⅲ）：咪唑啉酮类化合物的合成

Rovral[3-(3,5-二氯苯基)-1-异丙氨基甲酰乙内酰脲]是一种优良的广谱杀菌剂和种子处理剂,由于3,5-二氯苯胺不易制备,本文采用其它取代苯胺作为起始原料,采用固态光气制备异氰酸酯,中间体未经分离,经缩合、关环“一锅法”反应,得到化合物Ⅰ,进一步反应得到Ⅱ、Ⅲ系列新化合物。     

以固体光气为原料合成氯代甲酸(2-乙基)己酯

氯代甲酸(2-乙基)己酯是一种化工中间体,主要用来制备过氧化二碳酸二(2-乙基)己酯(简称EHP),EHP是一种高活性聚合引发剂。由固体光气和2-乙基己醇为原料合成氯代甲酸(2-乙基)己酯的研究未见报道。本文以固体光气和2-乙基己醇为原料合成了氯代甲酸(2-乙基)己酯,研究了反应物加入顺序、反应时间、反应温度、催化剂种类及用量对氯代甲酸(2-乙基)己酯收率和纯度的影响,得到了优化的合成工艺,对产物结构进行了分析,进一步用其合成了常用的高活性聚合引发剂过氧化二碳酸二(2-乙基)己酯(EHP)。     

光气法制备酰氯的催化剂研究进展

酰氯是一类用途非常广泛的重要有机合成中间体,在工业上制备酰氯主要使用的氯化剂包括PCl3、PCl5、SOCl2、光气等,充分反应后通过过滤、蒸馏等工艺进行脱色提纯制得酰氯。光气法由于对环境污染较低,是目前最常用的方法。三光气可以分解成光气,其优良的物理、化学性质以及便捷的储存和运输条件是光气的最佳替代化学品。但由于光气活性较低,在使用过程中添加催化剂必不可少,本文将重点介绍目前光气法制备酰氯时所使用的各种催化剂及其性能。