Synthesis of thieno[2,3-d]pyrimidine and quinazoline derivatives from monothiooxamides

A method for syntheses of previously unknown derivatives of thieno[2,3-d]pyrimidines and quinazolines from monothiooxamides was proposed.     

Reactions of monothiooxamides with O-methylhydroxylamine

The reactions of monothiooxamides with O-methylhydroxylamine were studied. Depending on the substituents in monothiooxamides, the reactions result in the formation of hydroxamic acid derivatives or various N-methoxy derivatives of amidoximes.     

Acyl derivatives of ivermectin 5-oxime with antifungal activity

Russian Chemical Bulletin - Acylation of ivermectin 5-oxime was first studied. Procedures for selective acylation of ivermectin 5-oxime either selectively at 5-oxime group or at both 5-oxime group...     

Synthesis of ivermectin-4″,5-diyl[bis(<Emphasis Type="Italic">N</Emphasis>-methylcarbamate)]

New ivermectin-4″,5-diyl[bis(N-methylcarbamate)] was synthesized by the MoO₂Cl₂(DMF)₂-catalyzed reaction of ivermectin with methyl isocyanate. The synthesized compound could find application as antiparasitic agent.     

Synthesis of 23-ketocholestane derivatives with different side-chain lengths (asterosapogenin analogs)

Syntheses were developed for 23-ketoasterosapogenin analogs with various sidechain lengths from dimethyl(tert-butyl)silyloxypregnenolone (DMTBS-pregnenolone) through 20-hydroxy-23-carboxylates or 22-acetylenic (C₅, C₆) derivatives by reduction and allylic rearrangement with concurrent oxidation of the intermediate 23-hydroxy-27-nor- and 27-nor-26-methylcholestanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 965–969, April, 1991.     

Transformed steroids. 133. Synthesis of 20-deoxysteroids with a tetrahydropyran ring E

The synthesis of 20-deoxy compounds — the precursors of the steroid pyranols and pyranones synthesized by the authors previously — has been effected from a steroid 20-ketotetrahydropyran by the hydrogenolysis of the corresponding ethylene dithioketal with Raney nickel. The¹H and¹³C NMR spectra have been studied in detail. Transformations of rings A and B via the epoxide or the 3,5-cyclosteroid have led to 3-acetoxy-16,23-epoxy-5H-21,24-dinorchol-5-en-6-one and 3-acetoxy-5-hydroxy-16,23-epoxy-21,24-dinorchol-5-en-6-one.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 732–735, November–December, 1983.     

Transformed steroids. 121. Synthesis of the δ-lactone of 3β-acetoxy-16α-hydroxy-6-oxo-24-nor-5α-chol-17(20)-en-23-oic acid

The synthesis of the ¹⁷⁽²⁰⁾-16 analog of natural chiogralactone is described. Attempts to introduce a 6-oxo group directly into the -lactone proved unsuccessful, since the first stage — saponification — took place with the formation of three products: the 3-hydroxy--lactone, the 3-hydroxy-²⁰⁽²²⁾-lactone, and the 15,17(20)-dienoic acid. The synthesis of the desired compound was effected from the ethyl ester of the 5,16-dienoic acid by the scheme 3-acetate3-tosylate6-hydroxy-3,5-cyclosteroid6-oxo-3,5-cyclosteroid6-oxo-5H--lactone. It has been shown that the cyclopropane ring in the 3,5-cyclosteroid -lactone is extremely stable under the conditions of acid treatments.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 184–187, March–April, 1981.     

Synthesis of sodium 5-sulfate-ivermectin and disodium 4″,5-disulfate-ivermectin

Treatment of ivermectin with sulfuric acid–acetic anhydride in pyridine gives sodium 5-sulfate-ivermectin and disodium 4″,5-disulfate-ivermectin. The synthesized salts are water-soluble compounds with promising antiparasitic activity.