Abstract: A method for purifying diatomaceous earth, whose natural colloidal structure is retained, which includes preparing a suspension of diatomaceous earth in a liquid wherein diatomaceous earth is insoluble, separating diatomaceous earth from the suspension, treating diatomaceous earth with an inorganic or organic acid, heat-treating the thus obtained product at a temperature not higher than 300° C., subjecting the product obtained to oxidative treatment and drying the purified product.

Abstract: The present invention is related to a method for purifying diatomaceous earth wherein the natural colloidal structure of the material is retained, which comprises preparing a suspension of diatomaceous earth in a liquid wherein diatomaceous earth is insoluble, separating diatomaceous earth from the suspension, treating diatomaceous earth with an inorganic or organic acid, heat-treating the thus obtained product at a temperature not higher than 300° C., subjecting the product obtained to oxidative treatment and drying the purified product. The invention also relates to a product obtainable by the above-mentioned method.

Abstract: The invention relates to a process for the preparation of 3-{2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl}-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one of the Formula (I), and pharmaceutically acceptable acid addition salts thereof by subjecting the oxime of the Formula (II), to ring-closure in the presence of an alkali hydroxide, alkali carbonate or alkali-C1-4 alkoxide in an inert organic solvent, converting the base of the Formula I thus obtained into an acid addition salt or setting free the base of the Formula I from an acid addition salt thereof which comprises reacting a halogen derivative of the general Formula (XIV), (wherein Hal is halogen) with piperidine oxime derivative of the Formula (V), or an acid addition salt thereof in the presence of a base, and using by the ring-closure of the oxime of the Formula II formed a C1-4-alkanol as inert solvent.

Abstract: The invention relates to a process for the preparation of 3-{2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl}-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one of the Formula (I), and pharmaceutically acceptable acid addition salts thereof by subjecting the oxime of the Formula (II), to ring-closure in the presence of an alkali hydroxide, alkali carbonate or alkali-C1-4 alkoxide in an inert organic solvent, converting the base of the Formula I thus obtained into an acid addition salt or setting free the base of the Formula I from an acid addition salt thereof which comprises reacting a halogen derivative of the general Formula (XIV), (wherein Hal is halogen) with piperidine oxime derivative of the Formula (V), or an acid addition salt thereof in the presence of a base, and using by the ring-closure of the oxime of the Formula II formed a C1-4-alkanol as inert solvent.

Abstract: The invention refers to a novel process for the preparation of cetirizine of formula (I) as well as to novel {2-[4-(&agr;-phenyl-p-chloro-benzyl)piperazin-1-yl]ethoxy}acetamides of formula II, wherein R1 and R2 represent, independently, a C1-4 alkyl group optionally substituted by a phenyl group, a C2-4 alkenyl group or a cyclohexyl group, or R1 and R2 form together with the adjacent nitrogen atom a morpholino group. According to the novel process, an acetamide of formula (II) is hydrolized, if desired in the presence of a phase transfer catalyst, to obtain cetirizine.