Patent GB-250577-A (GB)
Title: A process for the production of heterocyclical arsenic compounds
IPC: C07F9/80
Filed: 1926-04-01
Abstract: 250,577. Deutsche Gold-und Silber- Scheideanstalt vorm. Roessler. April 11, 1925, [Convention date]. Asymmetrical heterocyclic arseno compounds. -Relates to the preparation in known manner of organo arsenic compounds of the type R-As=As- R', in which R represents a substituted or non- substituted N-heterocyclic radicle and R<1> either a different N-heterocyclic radicle or an aromatic or aliphatic radicle. The compounds may be prepared bv condensing a heterocyclic arsenoxide or arsine halide with a heterocyclic or aromatic or aliphatic arsine, or a heterocyclic arsine with a heterocyclic or aromatic or aliphatic arsenoxide or arsine halide; or by reducing a mixture of two different heterocyclic arsinic acids or arsenoxides, or a heterocyclic arsinic acid or arsenoxide with an aromatic or aliphatic arsinic acid or arsenoxide; or by oxidizing a mixture of the arsines; or by interaction of a heterocyclic arseno compound with another heterocyclic arseno compound or an aromatic or aliphatic arseno compound to produce a mixed arseno compound. The condensation of arsines with arsenoxides or arsine halides is assisted by the presence of small quantities of mild reducing agents, such as hypophosphorous acid and its salts. The reaction between the arsines is effected by passing air or oxygen through their mixed solutions. The starting ma. terials may contain such groups as halogen, amino, hydroxyl, carboxyl and sulphonic groups, and these may be further substituted before or after, e.g. the amino group may be converted into its acetyl or methylene-sulphoxylate derivative. The N-heterocyclic arsenic compounds employed as starting materials may be prepared by dia.zotizing amino derivatives of N-heterocyclic compounds, followed by treatment with arsenites or arsenious acid; the resulting arsinic acids may then be reduced to the arsenoxide, arsine or arseno compound. The products are useful for the treatment of diseases caused by trypanosomes &c. According to the examples, (1) the following pairs of arsinic acids are reduced together to the arseno compound :-ana-quinolinearsinic acid and o-quinolinearsinic acid, 2-oxy-5-pyridylarsinic acid and o-quinolinearsinic acid, o-benzarsinic acid and 2-oxy-5-pyridylarsinic acid; (2) the same arseno compound is prepared by the reduction of a mixture of 3-nitro-4-oxyphenylarsinic acid and 2-oxy. 5-pyridylarsinic acid, or by treating 2-oxypyridine- 5-arsenoxide (prepared by reducing 2-oxypyridine- 5-arsinic acid in hydrochloric acid solution and hydrolyzing the resulting dichlorarsine) with 3- amino-4-oxyphenylarsine, or by the interaction of 4 : 4<1>- dioxy - 3 : 3'-diaminoarsenobenzene with 2 : 2<1> : 5 : 5<1>-diarsenopyridyl; the product may be treated with sodium formaldehyde sulphoxylate to give the methylenesulphoxylate. The Specification as open to inspection under Sect. 91 (3) (a) is not restricted to N-heterocyclic compounds, but refers to the use of heterocyclic compounds in general such as contain individually or in common nitrogen, sulphur, oxygen &c. as hetero members. This subject-matter does not appear in the Specification as accepted.