THIAZINES, in organic chemistry, a series of cyclic compounds containing a ring system of four carbon atoms, one nitrogen and one sulphur atom. These may be grouped in three ways, giving the following skeletal structures:-
Members of the first series have not as yet been isolated. Derivatives of the second type have been obtained by A. Luchmann (Ber. 1896, 29, p. 1429) by condensing γ-chlorbutylamine with carbon bisulphide or with mustard oils in the presence of caustic alkali; by M. Kahan (ibid., 1897, 30, p. 1321) on condensing bromhexylamine hydrobromide with thiobenzamide:
CH2CH(CH3)Br, HS > CH2·CH(CH3)·S
(CH3)2C·NH2 HN:C·C6H5 (CH3)2C - N=======C·C6H5
Benzothiazines are obtained from ortho-aminobenzyl halides and thio-amides:
C6H4 CH2Br CH2·S
N==C·CH3.
The most important thiazines are those derived from class III.,
thiodiphenylamine, C6H4N
SC6H4, being the parent substance
of the methylene blue series of dyestuffs. Thiodiphenylamine is obtained synthetically by heating sulphur with diphenylamine
or by the condensation of ortho-aminothiophenol with pyrocatechin.
It is a compound of neutral reaction. The first
known dyestufi of this series was Lauth's violet, which was
prepared by oxidizing paraphenylene diamine in acid solution
in the presence of sulphur. By using dimethyl paraphenylene
diamine in place of the simple diamine, methylene blue is
obtained. The relationship of these substances to thiodiphenylamine
was shown by A. Bernthsen, who, by nitration of
thiodiphenylamine, obtained a dinitro-compound which on reduction
was converted into the corresponding di-amino-derivative
and this on oxidation yielded Lauth's violet.
miaire (5th October 1795) he opposed those Thermidorians who
wished to postpone the dissolution of the Convention. At the
elections for the Corps Législatif he was elected by no less than
thirty-two departments. It was only by the intervention of
Boulay de la Meurthe that he escaped transportation after the
coup d'état of 18 Fructidor (4th September 1797), and he then
returned to the practice of his profession. The establishment
of the consulate brought him back to public life. He was made
prefect of the Gironde, and then member of the council of
state, in which capacity he worked on the civil code. He at
this time had Napoleon's confidence, and gave him wholehearted
support. He did not entirely conceal his disapproval
of the foundation of the Legion of
H NH N c.H.I'sHc.H.-> N01-CsH=<1; CeHa ~ N02 -> NH2- c.H.< S >c.H.-NH.-> HN:Col-Ia(S>c.H.-Nm Honour, of the Coucordat and of the Methylene blue is the most important of all blue basic dyes and is put on the market frequently in the form of its zinc chloride double salt, which is soluble in water. Acid oxidants in dilute aqueous solution convert it into methylene azure. See further A. Bernthsen, Ann., 230, p. 73; 251, p. 1; German Patents 45839 (1887); 47374 (1888). For a discussion as to the constitution of these dyestuffs, whether they are quaternary ammonium salts or thionium salts, see A. Hantzsch, Bef., 1906, 39, pp. 153, 1365; F. Kehrmann, ibid., 1906, 39, p. 914.