SU81881A1 - Method of producing sensitizers for halo-silver photographic emulsions - Google Patents

Description

Where;

, S, Se, CH CH, C (A1k) 2;

Z C or N;

Se, NH;

R and R are alkyl, aryl, aralkyl;

 or 1 (at, Y is absent)

No. 81881 2 are sensitizers for halo-silver photographic emulsions.

Of the compounds of this type, only dyes with thiazolidinedione- (2,4) residues are described, which are obtained by condensation of quaternary salts of acetanylinovinyl derivatives, for example benzthiazole, thiazoline, quinoline, etc., with thiazolidinedione or its N-alkyl- and aryl-derivative. However, due to the reduced reactivity of the methylene group of the thiazolidinediones, the yields of the dyes according to this method are very low and carbocyanines are formed as a by-product of the reaction, the separation of which often presents considerable difficulties.

The described method eliminates these drawbacks and allows to obtain dimethinmerocyanines, derivatives of thiazolidin-, imidazolides of din- and selenazolidinediones in good yields during the hydrolysis of quaternary salts of merocyanins containing a thionic group in position 2.

A distinctive feature of the method is that said quaternary salts are hydrolyzed by heating with water or dilute alcohol and the resulting dimetin-meridian derivatives are isolated in a known manner.

Example 1. A mixture of 3.5 g of 3-ethyl-5 (3-ethylbenzthiazolinylidene-2 ethylidene) thiazolidin-2-one 1a 4 and 3.78 g of dimethyl sulfate is heated with stirring for 15 minutes at 130 ° (inside the mixture). After cooling, the resulting quaternary salt is washed several times with absolute ether to a slightly yellow color of the latter (3-4 times with 20 ml each), the residue is dissolved in 100 ml of water and the solution is boiled for 2 hours. The precipitate is filtered and washed with water, alcohol and ether. Obtain 2.8 g (86.5% of theory) of a substance with a melting point of 219-220 °. After recrystallization from alcohol, the melting point does not change. The item is orange needles, the maximum absorption of the alcohol solution is 472 / pi.

Example 2. A mixture of 3.4 g of 3-ethyl-5- (and-ethyl dihydroquinolyl-iden-2 ethylidene) -thiazolidin-2-oHa-4 and 3.78 g of dimethyl sulfate are heated to 15 1 l at 110-115 ° C (inside the mixture) . The quaternary salt was washed with absolute ether as in Example 1, dissolved in 100 ml of water and the solution was boiled for 2 hours. A yield of 2.3 g (70% of theory) is obtained, with a melting point of 207 °. After recrystallization from alcohol, the melting point of the dye does not change. The product is red small needles. The maximum absorption of the alcohol solution is 502 mv-.

Example 3. A mixture of 3.8 g of 3-phenyl-5 (3-ethylbenzthiazolinylidene-2ethylidene) -imidazolidin-2-one-4 and 3.78 g of dimethyl sulfate is heated for 15 minutes. at a temperature of 120 ° (inside the mixture). The quaternary salt washed with absolute ether is dissolved in 250 m, l of water and a solution of boil for one hour. A yield of 2.9 W is obtained (80% of theory); melting point 183-184 °. After recrystallization from alcohol, the yield is 2.3 (65% of theory). The product is an orange-yellow needle with a melting point of 186-187 °. The maximum absorption of the alcohol solution is 506 mji.

Subject invention

The method of producing sensitizers for halo-silver photographic emulsions - dimethinmerocyanines, thiazolidine-imidazolidine- and selenazolidinediones- (2,4) derivatives from the quaternary merocyanin salts of general structure:

7СY

,one

I II I

N- (С С) „- C CH-CH

Y O, S, Se, CH CH. C (A1k) 2;

Z C or N;

Y S, Se, NH;

l, Ri and R2 alkyl, aryl, aralkyl

rt O or 1 (with and 1, Y 0)

characterized in that said quaternary salts are hydrolyzed by heating with water or a dilute alcohol and the resulting dimethinmerocyanine derivatives are isolated in a known manner::;