Patent GB-311208-A (GB)
Title: Process for the manufacture of cyclic compounds containing aldehydic groups
IPC: C07D209/86
Filed: 1928-02-06
Abstract: 311,208. Carpmael, A., (I. G. Farbenindustrie Akt.-Ges.). Feb. 6, 1928. Aldehydes; aldazines. - Aldehyde groups are introduced into cyclic compounds containing labile hydrogen atoms, in which other hydrogen atoms may be replaced by halogens or other monovalent substituents, except amino groups, by treatment with formamide or with derivatives thereof in which one of the hydrogen atoms of the amino group is substituted by aryl, and the other by alkyl, aralkyl on aryl, in the presence of an acid condensing agent containing chlorine, such as a chloride or oxychloride of phosphorus or sulphur or aluminium chloride. Suitable cyclic compounds are m-xylene, anthracene, N- ethylcarbazol, pyridine, quinoline, naphthostyril, naphtholethers, naphthalene, thioethers, oxythionaphthenes and anthrone and its nuclear substi. tution products. When using the formyl derivatives of secondary amines and cyclic compounds, such as oxythionaphthene and anthrone, containing in ring combination a methylene group and a Ketonic group capable of reacting in the tautomeric enolic form, chlorinated aldehydic derivatives are obtained, the hydroxyl group of the enolic form being replaced by chlorine. The reaction may be carried out in the presence of indifferent organic solvents. In examples, the following products are obtained, using formylmonomethylaniline and phosphorus oxychloride, in some cases in the presence of benzene : (1) panisaldehyde from anisol, (2) 2-ethoxy-1-naphthaldehyde from #-naphtholethylether, and 1-methoxy-5 : 6 : 7 : 8-tetrahydronaphthalene-4-aldehyde and 2-methoxy-5: 6 : 7 : 8-tetrahydronaphthalene. 1-aldehyde from 1- and 2-methoxy-5: 6 : 7 : 8. tetrahydronaphthalene, (3) anthracene-9-aldehyde from anthracene, and 1: 3-dimethyl-benzene-4- aldehyde from m-xylene, (4) a-chloranthracene-9- aldehyde from a-chloranthracene, and (5) 2- and 4-oxy-1-naphthaldehyde from #- and a-naphthol. In these examples, thionyl or sulphuryl chloride, or aluminium chloride may be used instead of phosphorus oxychloride, and other formylated secondary amines, such as formyldiphenylamine, or formamide, instead of formylmonomethylaniline. In a similar manner, 2: 7-dioxynaphthalene-1-aldehyde is obtained from 2: 7-dioxynaphthalene, 4: 8-dioxynaphthalene-1-aldehyde from 1: 5-dioxynaphthalene, 2-oxynaphthalene-1- aldehyde-3-carboxylic acid and the corresponding anilide from 2: 3-oxynaphthoic acid and its anilide, 2: 5-dimethyl-4-oxybenzaldehyde from pxylenol, 2: 4-dioxybenzaldehyde from resorcinol, and vanillin from guaiacol. In further examples, (6) 4-methyl-6-chlor-3-oxythionaphthene-2-aldehyde is obtained by heating 4-methyl-6-chlor-3- oxythionaphthene with formamide and anhydrous aluminium chloride or phosphorus oxychloride, (7) 6-ethoxy-3-oxythionaphthene-2-aldehyde is similarly obtained from 6-ethoxy-3-oxythionaphthene (8) N-ethylcarbazol is converted into an aldehyde by heating with formylmonomethylaniline and phosphorus oxychloride; pyridine and quinoline also yield aldehydes when similarly treated, and (9) naphthostyrilaldehyde is similarly obtained from naphthostyril. In further examples, in which chlorine is introduced at the same time as the aldehyde group, (10) 3-chlor-6-ethoxythionaphthene-2-aldehyde is obtained by treating 6. ethoxy-3-oxythionaphthene with formylmonomethylaniline and phosphorus oxychloride; 4- methyl-6-chlor-3-oxythionaphthene when similarly treated yields 4-methyl 3: 6 - dichlorthionaphthene-2-aldehyde, and (11) anthrone, when treated with formylmonomethylaniline or formyl. diphenylamine and phosphorus oxychloride yields 9-chloranthracene-10-aldehyde; when similarly treated, 2-chloranthrone yields 3: 10-dichloranthracene-9-aldehyde, 1 : 5-dichloranthrone yields 1: 5: 10-trichloranthracene-9-aldehyde, and desoxy-alizarine-dimethylether yields 1: 2-dimethnxy-lO-chloranthracene-9-nldehyde. The aldazines of most of the products are described.