Nucleophile Substitutionen an Kohlensäurederivaten. XX. Aminolyse des Bis(trichlormethyl)carbonates

Abstract

Nucleophilic Substitutions at Carbonic Acid Derivatives. XX. Aminolysis of Bis(trichlormethyl)carbonate The rate constants for the two steps of the reaction of bis(trichlormethyl)carbonate with substituted anilines have been determinated by conductivity measurements. The first relatively fast step of the reaction is the nucleophilic attack of the amine to the bis(trichloromethyl)‐carbonate leading to trichloromethylurethane through a six or four centers transition state in which the carbon‐nitrogen bond is formed parallel with the transfer of the proton. In this reaction a phosgene molecule is also produced, which reacts very fast with amine to form a N,N′‐diarylurea. The second, much slower step, is the nucleophilic attack of the amine to the trichloromethylurethane. Through a similar transition state in which the proton transfer has even a higher importance, a N,N′‐disubstituted urea and an other molecule of phosgene are formed.

Continuous-Flow Processes for the Production of Floxacin Intermediates: Efficient C–C Bond Formation through a Rapid and Strong Activation of Carboxylic Acids

“…11 It is widely used in the production of active pharmaceutical ingredients, agricultural chemicals, polymers, and fine chemicals. [12][13][14] Herein, we report an efficient C-C bond formation based on the concept of rapid activation of carboxylic acids with BTC to produce floxacin intermediates 1. This activation strategy only generates CO 2 and HCl as byproducts, making its utilization as a C-C coupling agent very interesting.…”

An Efficient and Convenient Route to Some Isoselenocyanates via Reaction of Formamides with Bis(trichloromethyl)carbonate and Selenium.

“…Herein, we report a new, ctTicient, convenient and safe method for the preparation of isoselenocyanates via reaction of N-substituted-fonnamides with bis(trichloromethyl)carbonate and selenium powder in the presence of triethylamine (Scheme I). 13is(trichloromethyl)carbonate, also named hexachlorodimethyl carbonate, trichloromethyl carbonate or 'triphosgcne', has been intensively investigated in the last several years as a synthetic auxiliary agent in the preparation of many important classes of organic compounds 9 , such as isocyanates 10 and isonitri les 11 . This white crystalline compound has proved to he safe and advantageous in comparison with its gaseous congener phosgene, however, the application of bis(trichloro-methy !…”

Phosgenation Reagents

“…In recent years, trichloromethyl chloroformate (diphosgene) [4,9] and bis-(trichloromethyl) carbonate (triphosgene) [10][11][12][13][14][15] (for reviews, see [16][17][18][19][20]) have frequently been used in organic synthesis as phosgene sources [11,21]. These liquid and crystalline phosgene equivalents, respectively, have the advantage of being much easier to handle than the gaseous phosgene.…”