Synthesis and antimicrobial evaluation of new pyridine, thienopyridine and pyridothienopyrazole derivatives.

The reaction of thiocyanoacetamide (1) with alpha,beta-unsaturated ketones 2a,b resulted in the formation of the corresponding newly synthesized 1(H)-pyridinethione derivatives 3a,b. Compounds 3a,b were used as synthons for the preparation of 2-S-alkyl-, 2-S-aryl-, 2-S-acetamidopyridine, thieno[2,3-b]pyridine and pyrazolo[3,4-b]pyridine derivatives via a wide range of reactions with different reagents. The antimicrobial activity of some of the newly synthesized compounds was tested. Compounds 3a, 11a, 15a, and 19a,b were found to be the most active ones.

Reactions of 3-aminopyrazole derivatives with cyanothioacetamide and its derivatives: Synthesis and reactions of several new pyrazole and pyrazole[3,2-b]pyrimidine derivatives.

Thiocarboxamidocinnamonitrile derivatives2 a-f reacted with 3-aminopyrazole derivatives3 a-c to give the pyrazole[3,2-b]pyrimidine derivatives6 a-p. Compounds6 a-p were used as starting material for syntheses of several heterocylic coompounds. Dehydrogenation of6 gave pyrazole[3,2-b]pyrimidines10 a-d while its reaction with diethyl oxalate gave11. Reactions of6 with formic acid gave pyrazolopyrimidines17 a-j, and pyrazolopyrimidopyrimidinoes18 a-j.

Reactions of pyrimidinonethione derivatives: Synthesis of 2-hydrazinopyrimidin-4-one, pyrimido[1,2-a]-1,2,4-triazine, triazolo-[1,2-a]pyrimidine, 2-(1-pyrazolo)pyrimidine and 2-arylhydrazonopyrimidine derivatives.

6-Aryl-5-cyano-4-pyrimidinon-2-thione derivatives1a-c reacted with ethyl iodide to give the corresponded 2-S-ethylpyrimidin-4-one derivatives2a-c. Compounds2a-c was, in turn, reacted with hydrazine hydrate to give the sulfur free reaction products,3a-c. These reaction products were taken as the starting materials for the synthesis of several newly synthesized heterocyclic derivatives. Reactions with several halogenated ketones, esters, chloroacetic acid and chloroacetamide give pyrimidotriazines8, 12 and15 while their reactions with formic acid, acetic acid and carbon disulfide gave the corresponded triazolopyrimidines17 and21. The reaction with both acetyl acetone and ethylacetoacetate gave the corresponded 2-(3', 5'-dimethyl-1'-pyrazoly) pyrimidine derivatives20a-c and24a-c respectively while the reaction with cinnamonitriles25a-h afforded the corresponded aryl hydrazopyrimidines27a-f. The structures of these reaction products were established based on both elemental analyses and spectral data studies.

Microdetermination of vitamin D2 (ergocalciferol) using N-bromosuccinimide.

A novel method for the microdetermination of vitamin D2 in its pure state and pharmaceutical preparations using N-bromosuccinimide (NBS) is reported. The new method is easy, simple, and accurate.