Yeda Research and Develpment & Co. Ltd

Aureliu J Acher

Yehuda Mazur

Lea Shragina

Dalia Freeman

Moshe Avramoff

Novel 3,7-disubstituted phenothiazinium salts are active in the photochemical disinfection of aqueous effluents. The novel salts are of the general formula ##STR1## wherein: either R.sub.1 is a saccharide residue;

Phenothiazinium salts and their use for disinfecting aqueous effluents

A process for the production of 1.alpha.-hydroxy provitamin D.sub.3 which comprises treating 1.alpha., 2.alpha.-epoxy-cholesta-4,6-diene-3-one at a low temperature with liquid ammonia; with ammonium chloride and with lithium metal to produce 1.alpha.,3.beta.-dihydroxycholest-6-ene, converting this to the corresponding 1.alpha.,3.beta.-di(lower alkanoyl) derivative, reacting the latter with bromine to give 1.alpha.,3.beta.-di(lower alkanoyloxy) 6.beta.,7.alpha.-dibromocholestane, which is dehydrobrominated to give 1.alpha.,3.beta.-di(lower alkanoyloxy)-cholesta-5,7-diene, which is converted to the desired provitamin. The 1.alpha.,3.beta.-di(lower alkanoyloxy)cholest-6-ene can be oxidized to the corresponding 5-ene-7-one, which is converted to the 7-p-toluenesulfonyl hydrazone derivative, which is converted to the 1.alpha.-hydroxy provitamin D.sub.3 di(lower alkanoyloxy) derivative or to the 1.alpha.-hydroxy provitamin D.sub.3. Novel compounds are 1.alpha.,3.beta.-dihydroxy-cholest-6-ene, its di(lower alkanoyloxy) derivative; 1.alpha.,3.beta.-di(lower alkanoyloxy)-6.beta.,7.alpha.-dibromocholestane; 1.alpha.,3.beta.-diacetoxycholest-5-ene-7-one and the corresponding 7-p-toluenesulfonylhydrazone derivative.

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Ramat Gan, Israel

Aureliu J Acher