Abstract:
Methods are provided for making certain 6,7-dihalo-1,5-dihydroimidazo[2,1-b]quinazolin-2(3H)-ones from 2,3-dihalobenzaldehydes. A method is also provided for making the intermediate ethyl N-(2,3-dihalo-6-nitrobenzyl)glycines from 2,3-dihalobenzaldehydes and for reducing the glycine compounds using either SnCl 2 or a specially defined catalyst. A cyclization method to form the desired 6,7-dihalo-1,5-dihydroimidazo[2,1-b]quinazolin-2(3H)-ones from the corresponding iminoquinazoline compounds is further provided. These methods are particularly suitable in the manufacture of Anagrelide base.
Abstract:
A polysilane-supported transition metal catalyst or (polysilane/inorganic compound)-supported transition metal catalyst which comprises as a polymeric support either a polysilane compound or a combination of a polysilane compound and an inorganic compound and, supported thereon, any of various transition metals. The catalyst is sparingly soluble in hydrocarbons or alcohols and is useful as a heterogeneous-system catalyst for various organic synthesis reactions using those compounds as solvents. The polysilane having a transition metal supported thereon can be easily crosslinked by heating, microwave irradiation, ultraviolet irradiation, or a chemical technique, e.g., hydrosilylation to become insoluble in various solvents while retaining the catalytic activity. By supporting this polysilane-supported transition metal catalyst on an inorganic compound, stability and handleability are improved. These polysilane-supported transition metal catalysts have high activity in hydrogenation, hydrosilylation, Heck reaction, Suzuki-Miyaura coupling reaction, and other reactions. The catalysts can be easily recovered and reused and are extremely less apt to release the metal.
Abstract:
Methods are provided for making certain 6,7-dihalo-1,5-dihydroimidazo[2,1-b]quinazolin-2(3H)-ones from 2,3-dihalobenzaldehydes. A method is also provided for making the intermediate ethyl N-(2,3-dihalo-6-nitrobenzyl)glycines from 2,3-dihalobenzaldehydes and for reducing the glycine compounds using either SnCl 2 or a specially defined catalyst. A cyclization method to form the desired 6,7-dihalo-1,5-dihydroimidazo[2,1-b]quinazolin-2(3H)-ones from the corresponding iminoquinazoline compounds is further provided. These methods are particularly suitable in the manufacture of Anagrelide base.
Abstract:
A process for producing an esterificated condensate, wherein a monomeric ester or thioester, or a polyester or polythioester is produced by carrying out a direct condensation reaction from a carboxylic acid and an equimolar amount of an alcohol or a little excess amount of a thiol in a non-polar solvent such as toluene using, as a (poly)condensation catalyst, a tetravalent hafnium compound, typically, hafnium(IV) chloride, in particular hafnium(IV) chloride . (THF)2 and hafnium(IV) butoxide in an oxygen-free atmosphere under reflux. During refluxing with heating, water being distilled as an azeotropic mixture is preferably removed from the reaction system. The process permits a catalytic esterification using equimolar amounts of a carboxylic acid and an alcohol and a catalytic thioesterification using a carboxylic acid and an equimolar or a little excess amount of a thiol, and accordingly is greatly promising as a commercial process for a large scale production from the view point of green chemistry.
Abstract:
A method of obtaining bromated aromatic and heterocyclic combinations containing acceptor groups provides for bromination of aromatic and heterocyclic combinations, containing acceptor groups, with bromine or hydrobromic acid, the process being carried out in the presence of sulphuric acid or oleum in combination with nitric acid or its salts at a temperature of 20-120°C at the following molar ratio of the reagents per mol of the initial compounds: bromine 0.5-3.2 or a salt of hydrobromic acid 1.0-7.0, nitric acid 0.5-3,0 or a salt of nitric acid 1.4-4.0, sulphuric acid or oleum 6.0-70.0. The obtained combinations may be used as antipyretics, as intermediate products in synthesis of dyes, pigments, herbicides and for other purposes.