Abstract: The present invention relates to a process for preparing fluorescein quinoid form of Formula (I): Furthermore, the present invention relates to a new solid fluorescein form and a process for the preparation thereof. The present invention also relates to the use of said new solid fluorescein form in the synthesis of fluorescein quinoid form.

Abstract: The present invention relates to a process for preparing fluorescein quinoid form of Formula (I): Furthermore, the present invention relates to a new solid fluorescein form and a process for the preparation thereof. The present invention also relates to the use of said new solid fluorescein form in the synthesis of fluorescein quinoid form.

Abstract: A process for the preparation of highly pure 1-(mercaptomethyl)-cyclopropaneacetic acid is described. Treatment of 1-(hydroxymethyl)-cyclopropaneacetonitrile with an acid provides the corresponding imino ester and/or halo-amide, which when reacted with thiourea provide the corresponding amide-isothiuronium salt. Hydrolysis of the amide-isothiuronium salt followed by an in situ oxidation allows the facile isolation and purification of 1-[1 -(carboxymethyl)-cyclopropanemethyldisulfanylmethyl]-cyclopropaneacetic acid (also known as 1-(mercaptomethyl)-cyclopropaneacetic acid disulfide). Reduction of the 1-(mercaptomethyl)-cyclopropaneacetic acid disulfide under mild conditions provides the 1-(mercaptomethyl)-cyclopropaneacetic acid with high purity.

Abstract: Halogenated N-sulfamyl propionamidine addition salts corresponding to the formula ##STR1## are provided, in which X represents halogen and A represents an acid selected from sulfuric acid, nitric acid, benzenesulfonic acid; toluenesulfonic acid; 2,4,5-trichlorobenzenesulfonic acid; trichloroacetic acid; trifluoroacetic acid or methanesulfonic acid. They are useful as intermediates in the preparation of famotidine. They are prepared by reacting a halogenated propionitrile with the respective acid.