141-30-0Relevant articles and documents
Intermolecular contacts in the crystal structures of specifically varied halogen and protonic group substituted azines
Hübscher, J?rg,Seichter, Wilhelm,Weber, Edwin
, p. 3026 - 3036 (2017)
A series of azines featuring differently halogen and protic group substituted pyridine, pyrimidine and pyridazine compounds have been synthesized and studied in terms of their crystal structures in order to develop a better understanding of the links between structural conditions and molecular packing behavior. Complemented by the structure results of related compounds known from the literature, intermolecular contact relationships connected to the present substance types were found, having potential use in future crystal engineering of similar compounds. This primarily involves the formation of N?I contacts aside from specific halogen?halogen and hydrogen bond type interactions.
Polymorph-specific chlorination of maleic-hydrazide
Katrusiak, Andrzej,Katrusiak, Anna
, p. 203 - 210 (2003)
The reaction of chlorination of maleic-hydrazide (1) with POC13 is specific to the substrate polymorph. Chlorination of either the triclinic polymorph of maleic-hydrazide (1), denoted MH1, or the monoclinic polymorph MH2 leads to a single product of 3,6-dichloropyridazine (2), while chlorination of the monoclinic polymorph MH3 under the same conditions results in two products: 3,6-dichloropyridazine (2) and 6-chloro-3-pyridazinone (3). The structural differences between polymorphs and their topochemical chlorination in phosphorus oxychloride are discussed. The crystal structure of 6-chloro-3-pyridazinone (3) monohydrate, determined in this study by X-ray diffraction, is built of ribbons of hydrogen-bonded 3 and water molecules. It has been established that the chlorination of ground crystals of polymorph MH3 yields exclusively the dichloropyridazine, which suggests that the crystal habit of MH3, the size of crystallites and the lower solubility of MH3 than MH1 and MH2 are the main reasons for the different course of the reaction.
Deaminative chlorination of aminoheterocycles
Ghiazza, Clément,Faber, Teresa,Gómez-Palomino, Alejandro,Cornella, Josep
, p. 78 - 84 (2021/12/23)
Selective modification of heteroatom-containing aromatic structures is in high demand as it permits rapid evaluation of molecular complexity in advanced intermediates. Inspired by the selectivity of deaminases in nature, herein we present a simple methodology that enables the NH2 groups in aminoheterocycles to be conceived as masked modification handles. With the aid of a simple pyrylium reagent and a cheap chloride source, C(sp2)?NH2 can be converted into C(sp2)?Cl bonds. The method is characterized by its wide functional group tolerance and substrate scope, allowing the modification of >20 different classes of heteroaromatic motifs (five- and six-membered heterocycles), bearing numerous sensitive motifs. The facile conversion of NH2 into Cl in a late-stage fashion enables practitioners to apply Sandmeyer- and Vilsmeier-type transforms without the burden of explosive and unsafe diazonium salts, stoichiometric transition metals or highly oxidizing and unselective chlorinating agents. [Figure not available: see fulltext.]
Preparation method of 3, 6-dichloropyridazine
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Paragraph 0034-0039, (2021/04/14)
The invention belongs to the technical field of medicines, and particularly relates to a preparation method of 3, 6-dichloropyridazine. The preparation method comprises the following steps: carrying out chlorination reaction on 3, 6-dihydroxypyridazine and N-chlorosuccinimide to generate 3, 6-dichloropyridazine; the chlorination reaction route is as follows: the method solves the technical problems of large environmental pollution, high process risk and high cost due to the adoption of the traditional chlorinating agent in the existing 3, 6-dichloropyridazine preparation method.
