The present invention relates to a process for the purification of compound of formula II, wherein X may be independently selected from trifluoroacetic acid, hydrochloric acid, hydrobromic acid, p-toluene sulfonic acid and phosphoric acid; its isolation as solid and use for the preparation of carfilzomib. ##STR00001##

The present invention relates to a process for the purification of compound of formula II, wherein X may be independently selected from trifluoroacetic acid, hydrochloric acid, hydrobromic acid, p-toluene sulfonic acid and phosphoric acid; its isolation as solid and use for the preparation of carfilzomib. ##STR00001##

The present invention concerns a process for the reduction of content of carboxylic acids and derivatives thereof in oleum, disulfuric acid or concentrated sulfuric acid. The invention further concerns a process for the manufacture of carboxylic acid anhydrides comprising the process for the reduction of content of carboxylic acids and derivatives thereof from oleum, disulfuric acid or concentrated sulfuric acid.

The present invention concerns a process for the reduction of content of carboxylic acids and derivatives thereof in oleum, disulfuric acid or concentrated sulfuric acid. The invention further concerns a process for the manufacture of carboxylic acid anhydrides comprising the process for the reduction of content of carboxylic acids and derivatives thereof from oleum, disulfuric acid or concentrated sulfuric acid.

The present invention concerns a process for the reduction of content of carboxylic acids and derivatives thereof in oleum, disulfuric acid or concentrated sulfuric acid. The invention further concerns a process for the manufacture of carboxylic acid anhydrides comprising the process for the reduction of content of carboxylic acids and derivatives thereof from oleum, disulfuric acid or concentrated sulfuric acid.

Compounds of general formula (I) wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and X are as defined herein are inhibitors of the epithelial sodium channel (ENaC) and are useful for the treatment or prevention respiratory diseases and conditions, skin conditions and ocular conditions.

##STR00001##

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.