| 摘要 |
1360490 Pyrazolines FARBWERKE HOECHST AG 19 April 1971 [11 March 1970] 23815/71 Heading C2C [Also in Division C5] Compounds of formula wherein R is a C 1 -C 4 alkyl group, R<SP>1</SP> is hydrogen or an optionally substituted pheny group, and X is an ethylenically unsaturated radical or an optionally substituted saturated aliphatic radical are prepared by one or more of (a) condensation of a 3,4-dichloro-6-R-phenylketone with a hydrazinophenyl sulphone, (b) esterification of a hydroxyalkyl sulphone, (c) splitting of an ester group formed in (b), optionally without isolation, to form a double bond, (d) hydrogenation of a double bond formed in (c), (e) additive saturation of a double bond formed in (c) by reaction with a compound having at least one active hydrogen atom, (f) quaternization of an amino compound formed in (e), or (g) conversion of a compound wherein X is a hydroxy group to the corresponding sulphinic acid salt and reacting this with an optionally substituted alkyl halide or with an epoxide. The products are optical brightening agents. 3,4 - Dichloro - 6 - R- or 6 - H - acetophenones, propiophenones and #-chloro-propiophenones are prepard by Friedel-Crafts acylation. The sodium salt of 2-sulphostyryl-3<SP>1</SP>,4<SP>1</SP>-dichloro- 6<SP>1</SP>-methyl-phenyl ketone is prepared by reaction of 3,4-dichloro-6-methyl-acetophenone with the sodium salt of benzaldehyde-2-sulphonic acid. 2,4-Dichloro-n-propyl-benzene is prepared by reduction of 2,4-dichloro-propiophenone. The compounds of Formula I are used as optical brighteners for polymers, which may be added before or after polymerization. In an example, an acrylonitrile copolymer containing a brightener is spun from DMF solution. |
