Patent GB-286685-A (GB)
IPC: C09B3/04
Filed: 1928-02-04
Abstract: 286,685. I. G. Farbenindustrie Akt.- Ges. March 9, 1927, [Convention date]. Addition to 268,830. Samples furnished. Benzanthrone derivatives. - In the parent Specification is described inter alia the production of Bz1-hydroxybenzanthrones by condensing reduction products of anthraquinone containing oxygen in the meso-position with esters of unsaturated carboxylic acids of the formula where R2 is a residue like hydroxyl or alkoxyl, and R1 any univalent residue such as aryl, acyl, or a carboxylic ester group. This reaction is now applied to a-#-unsaturated carboxylic acids and esters thereof in which R2 is hydrogen, alkyl, or aryl and R, is hydrogen, aryl, or a carboxylic ester group. The process is also applicable to the said unsaturated carboxylic acids in which the double bond has been opened by the addition of hydrogen halide, water, &c., for example, #- hydroxybutyric acid or #-chlorpropionic acid. The Bz1-oxybenzanthrones can be obtained directly or the intermediate products obtained during the reaction can be isolated and the benzene ring of the benzanthrone molecule closed by treatment with acid condensing agents, oleum or chlorsulphonic acid being used when R2 is an aryl group; sulphonation of the products can be avoided by addition of a diluent such as acetic anhydride. According to examples, (1) Bz1-oxybenzanthrone is obtained by condensing anthrone with acrylic acid or #-chlorpropionic acid in presence of sulphuric acid of about 90 per cent strength ; (2) anthrone is heated with #-chlorpropionic acid alone to obtain #-anthronylpropionic acid ; the latter yields Bz1-oxybenzanthrone by heating with sodium aluminium chloride in the way described in example 2 of Specification 277,342, or with phosphorus oxychloride, and a sulphonic acid of Bz1-oxybenzanthrone by heating with concentrated sulphuric acid; (3) #- anthronyl-#-methylcrotonic acid is obtained by heating anthrone with crotonic acid and is converted into Bz1-oxy-Bz3-methylbenzanthrone by warming with chlorsulphonic acid diluted with glacial acetic acid. (4) #-anthronyl-#-phenylpropionic acid is obtained by condensing anthrone with cinnamic acid in presence of a little piperidine and is converted into Bz1-oxy-Bz3-phenylbenzanthrone by means of chlorsulphonic acid and glacial acetic acid ; (5) Bz1-oxy-Bz3-phenylbenzanthrone sulphonic acid is obtained by treating anthrone-benzmalonic acid dimethyl ester which oleum of 20 per cent strength at 100‹ C. Bz1-oxy-Bz3-phenylbenzanthrone yields by action of ammonia, in presence of zinc chloride the Bz1-amino-Bz3-phenylbenzanthrone from which the amino group can be eliminated by the diazo reaction so as to obtain Bz3-phenylbenzanthrone. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the use as parent materials of a-#-unsaturated carboxylic acids and esters in which R2 may be halogen, in addition to the substituents mentioned above, and R1 may be any univalent residue, alkyl, aryl, aralkyl, aroyl, halogen, and hydroxyl being mentioned in addition to the substituents already referred to. This subject-matter does not appear in the Specification as accepted.