Abstract:
A process for preparing 1,2- and 1,3-dinitrate esters from polyols containing 1,2- or 1,3-diol fragments involves using an alkyl or aryl boronic acid to form a cyclic boronate ester derivative which is then reacted with dinitrogen pentoxide to directly generate the dinitrate ester. In the cyclic ester form the 1,2- or 1,3-hydroxyl groups are protected and other reactions may then be carried out on other parts of the molecule of which the fragment forms a part, leaving the dinitrate ester to be produced subsequently in the final step. High yields are obtained at both stages.
Abstract:
Procédé permettant d'obtenir un rendement élevé d'esters de nitrate solubles dans l'eau ou dans l'acide sans recours à des solvants organiques dans la réaction de nitratation et sans produire des produits ou des produits secondaires instables. Le procédé consiste à nitrater un composé organique à teneur en hydroxy à l'aide d'un agent de nitratation approprié tel que l'acide nitrique en l'absence de solvants organiques dans la réaction de nitratation. On neutralise le mélange réactionnel, ce qui provoque la précipitation ou la séparation des esters de nitrate de la solution de nitrate neutralisée. Ensuite, on récupère l'ester de nitrate et l'on peut en enlever tous les éventuels sels de nitrate dissous par un lavage délicat avec de l'eau ou avec une solution diluée d'halogénure. Selon le procédé, on n'utilise aucun solvant organique dans la réaction de nitratation, et les rendements moyens sont compris entre environ 80 % et environ 95 %.
Abstract:
The invention concerns a process for the preparation of nitric acid esters of organic hydroxy compounds by reacting an organic hydroxy compound with nitric acid in the presence of sulphuric acid and in a solvent, followed by separating off the spent acid, substantially neutralizing the residual acidity of the organic solution, and removing solvent to leave the organic nitrate. From 95% to 220% of the stoichiometric requirement of nitric acid for complete nitration is used. The mole ratio of water to sulphuric acid at the end ofthe reaction is from 0,2:1 to 2,5:1. From 200 to 2000 ml of solvent per mole of hydroxy group is present. Yields of at least 92% are obtained. The invention is particularly suitable for the preparation of alkyl nitrates, alkylene or polyalkylene glycol, monoalkyl ether mononitrates, alkylene or polyalkylene glycol dinitrates, diol nitrates, nitrates containing homocyclic or heterocyclic rings, or nitrates derived from polyols.
Abstract:
The invention concerns a process for the preparation of nitric acid esters of organic hydroxy compounds by reacting an organic hydroxy compound with nitric acid in the presence of sulphuric acid and in a solvent, followed by separating off the spent acid, substantially neutralizing the residual acidity of the organic solution, and removing solvent to leave the organic nitrate. From 95% to 220% of the stoichiometric requirement of nitric acid for complete nitration is used. The mole ratio of water to sulphuric acid at the end ofthe reaction is from 0,2:1 to 2,5:1. From 200 to 2000 ml of solvent per mole of hydroxy group is present. Yields of at least 92% are obtained. The invention is particularly suitable for the preparation of alkyl nitrates, alkylene or polyalkylene glycol, monoalkyl ether mononitrates, alkylene or polyalkylene glycol dinitrates, diol nitrates, nitrates containing homocyclic or heterocyclic rings, or nitrates derived from polyols.
Abstract:
4-nitroxybutyl ester of the 2-(S)-(6-methoxy-2-naphthyl)-propanoic acid having an enantiomeric excess of the (S) form higher than or equal to 97%.
Abstract:
PROBLEM TO BE SOLVED: To obtain a naproxen nitroxyalkyl ester having an enantiomeric excess of at least 97%, preferably 98% or higher. SOLUTION: A halide of 2-(S)-(6-methoxy-2-naphthyl)-propionic acid of formula A-Hal (wherein A is an acyl residue of an acid) is reacted with an aliphatic nitroxyalkanol HO-Y-ONO 2 (wherein Y is a 1C-20C alkylene group or a 3C-8C cycloalkylene group or an alkylene group as defined and including a cycloalkylene group as defined) in an inactive organic solvent under the presence of an inorganic base. Thus is produced a nitroxyalkyl ester of 2-(S)-(6-methoxy-2-naphthyl)-propionic acid having an enantiomeric excess of at least 97%, preferably 98% or higher. COPYRIGHT: (C)2011,JPO&INPIT