摘要:
The invention relates to a method for the preparation of 4,6-dichloropyrimidine by reacting 4-chloro-6-methoxypyrimidine with phosgene as chlorinating agent in the presence of a nitrogen-containing auxiliary.
摘要:
Grignard reagents which contain a protected aldehyde function are obtained in a particularly advantageous manner from a halogenated aldehyde by reaction with a secondary monoamine to give an open-chain aminal, and conversion of the latter into a Grignard reagent using metallic magnesium. The invention also relates to novel Grignard reagents of this type.
摘要:
The invention discloses a novel thermally-responsive record material comprising a support having coated thereon a thermally sensitive color forming composition comprising a chromogenic material, an acidic developer material and a certain carbamate component that does not include dodecyl-N-phenylcarbamate. The novel record material displays enhanced image intensity or improved thermal response.
摘要:
2-Amino-5-alkyl-phenols, which are suitable as intermediates in the production of crop-protection agents or photographic couplers, can be prepared by subjecting 2-amino-5-alkyl-benzenesulphonic acids or their salts to alkaline hydrolysis.
摘要:
The novel compound (2,3-dihydro-5-benzofuranyl)-acetonitrile is prepared by chloromethylating 2,3-dihydro-benzofuran and reacting the resulting 2,3-dihydro-5-chloromethyl-benzofuran with a cyanide. (2,3-Dihydro-5-benzofuranyl)-acetonitrile can be converted by saponification to (2,3-dihydro-5-benzofuranyl)-acetic acid, an important intermediate for the manufacture of various pharmaceutical active substances. This intermediate has hitherto been obtainable only by a laborious procedure and in low yields.
摘要:
Unsubstituted or substituted 2-fluoro-pyrimidines can be prepared by reaction of the underlying 2-amino-pyrimidines with diazotization agents, mixtures of HF and H.sub.2 O containing 30-70% by weight of HF, based on the total of HF and H.sub.2 O, serving as reaction medium. The reaction medium can also contain diluents and/or inorganic salts, preferably fluorides.
摘要:
The invention relates to a method for removing heavy metal sulphides from dilute aqueous systems as they are present in numerous chemical processes. The method is characterized in that water-soluble polymers such as polyethyleneimines, homopolymers or copolymers of derivatives of acrylic acid or methacrylic acid or homopolymers or copolymers of styrenesulphonic acids are added to said systems and the systems are then filtered.
摘要:
The invention relates to a method for the preparation of 4,6-dichloropyrimidine by reacting 4-chloro-6-methoxypyrimidine with at least one sulphur-containing chlorinating agent selected from the group consisting of SCl2, SOCl2, and SO2Cl2 in the presence of at least one phosphorus compound having the formula R3P═Yn (1), in which R represents C1-C10-alkyl or C6-C10-aryl, each of which may optionally be substituted by up to five identical or different substituents selected from the group consisting of fluorine, chlorine, bromine, C1-C4-alkyl, and C1-C4-alkoxy, Y represents oxygen or sulphur, and n represents zero or 1.
摘要:
The invention relates to a process for the preparation of 4,5,6-trichloro- and 2,4,5,6-tetrachloropyrimidine starting from 3-dimethylamino-propionitrile, to its use and also to a crystalline intermediate product form.
摘要:
2-Chloroacrylonitrile is prepared in a particularly advantageous and readily industrially practicable manner by chlorinating acrylonitrile and then thermally cleaving the 2,3-diehloropropionitrile formed, by chlorinating acrylonitrile in the presence of a catalyst system comprising dimethylformamide and pyridine and/or pyridine derivatives and subjecting the resulting crude 2,3-dichloropropionitrile to thermal cleavage in the presence of the same catalyst system without the addition of further catalysts.