Patent GB-553143-A (GB)
Title: Improvements in or relating to the production of organic compounds especially intended for use as dyestuff intermediates
IPC: C07D293/12
Filed: 1941-11-06
Abstract: 553,143. Sulphur compounds. KENDALL, J. D., WOOD, H. W., and MAJER, J. R. Nov. 6, 1941, No. 14312. Samples furnished. [Class 2 (iii)] A dye intermediate of the formula is prepared by reacting a compound of the formula with an alkyl or aralkyl mercaptan (R 5 SH) in the presence of a strong acid (HA) or an alkyl salt of such acid. D represents the residue of a 5- or 6-membered heterocyclic nitrogen compound (e.g. a substituted or unsubstituted thiazole, thiazoline, oxazole, oxazoline, selenazole, selenazoline, pyridine, quinoline, lepidine, indolenine, diazine, e.g. pyrimidine, thiodiazole, or quinazoline, the corresponding substituted or unsubstituted polycyclic compounds, e.g. benzthiazoles, naphthathiazoles, or anthrathiazoles, or the diazines described in Specification 425,609). R 1  is an alkyl or aralkyl group, R 2  is hydrogen or an alkyl or aralkyl group, R 3  and R 4  are hydrocarbon groups (e.g. alkyl, aryl or aralkyl groups, preferably lower alkyl groups), and n is 0 or 1. R 1 , R 2  and R 5  are also preferably lower alkyl groups. Any of the alkyl, aryl, or aralkyl groups may be substituted, e.g. by hydroxy or amino groups. The strong acid is preferably dry hydrochloric acid gas, but other hydrohalic acids, or nitric, sulphuric, phosphoric or p - toluenesulphonic acid, may also be used. Alkyl halides, e.g. methyliodide may also be employed. Intermediates obtained as chlorides may be converted to bromides or iodides by treatment with potassium bromide or iodide. In an example, a dye intermediate is obtained by passing dry hydrochloric acid gas through a mixture of 1 - (# - diacetylpropenylidene) - 2 - methyldihydrobenzthiazole, methyl alcohol (solvent), and ethyl mercaptan. The corresponding N - ethyl compound may also be prepared. Dye intermediates may be similarly obtained from (a) a mixture of 2 - (# - diacetylpropenylidene) - 1 : 3 : 3 - trimethylindolenine, benzene, and ethyl mercaptan or a mixture without the benzene ; (b) a mixture of 1 : 6 - dimethyl - 2 - (# - acetylpropenylidene) - 1 : 2 - dihydroquinoline, methyl alcohol, and ethyl mercaptan (1 : 6 - dimethyl - 2 - (# - acetylpropenylidene) - 1 : 2 - dihydroquinoline being obtained as bye-product; (c) 1 - (# - diacetylpropenylidene) - 2 - methyldihydrobenzselenazole and ethyl mercaptan ; and (d) 1 - ( #- diacetylpropenylidene) - 2 - # - hydroxyethyldihydrobenzthiazole and ethyl mercaptan. In another example, 2 - ( w - diacetylpropenylidene) - 1 : 3 : 3 - trimethylindolenine, ethyl mercaptan, and methyl iodide are dissolved in benzene and allowed to stand. In a further example, 2 - (# - dipropionylpropenylidene) - 1 : 3 : 3 - trimethyl indolenine, ethyl mercaptan, and methyl iodide are mixed and allowed to stand. Samples have been furnished under Sect. 2 (5) of (a) an intermediate prepared by reacting 2 - (# - diacetylpropenylidene) - N - methyldihydrothiazoline, ethyl mercapton, and sulphuric acid and of (b) an intermediate prepared by reacting 1 - diacetyl - 3 - (N - methyldihydrobenzthiazolylidene) - 1 - butene, ethyl mercaptan, and sulphuric acid. According to the Provisional Specification, the intermediates may be derived from compounds of the formula wherein D is the residue of a heterocyclic nitrogen nucleus, R 1  is an alkyl or aralkyl group R 2  and R 3  are hydrogen atoms or alkyl, aryl, or aralkyl groups (the same or different), R 4  and R 5  are alkyl, aryl, or aralkyl groups, n is 0 or 1, and m is a positive integer.