Dihydropyrimidines as Precursors for Synthesizing of Oxoketene gem-Dithiol and 1,2-Dithiol-3-Thione, a Facile Synthesis and Convenient Reaction Transformations

Abstract

In the present work the authors could synthesize the substrates oxoketene gem-dithols 5, ketene dithioacetal 6 and 1,2dithiol-3-thione 39 from compounds bearing both nucleus indole and dihydropyrimidines together due to their biological and pharmacological activities. In this paper, and as a result of biological and pharmacological activities of oxoketene gemdithiols, ketene dithioacetal and/or 1,2-dithiol-3-thione; we synthesized various derivatives of them via indole and dihydropyrimidine in the form of either condensed or fused derivatives. We used ecofriendly methods such as pure orange juice as a green solvent and as an acid catalyst in the same time to prepare, 1-[2-imino-4-(1H-indol-3-yl)-6-methyl-1,2,3,4tetrahydropyrimidin-5-yl]-ethan-1-one 4a and/or 1-[4-(1H-Indol-3-yl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl]ethan-1-one 4b. Subsequently, the substrate 4b was treated with different reagents to afford, 1-(4-(1H-indol-3-yl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-3,3-dimercaptoprop-2-en-1-one 5 and/or 1-(4-(1H-indol-3-yl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-3,3-bis(methylthio)prop-2-en-1-one 6. Compounds 5 and/or 6 were used as synthons to get various heterocyclic compounds such as 3-(4-(1H-indol-3-yl)-6-methyl-2-(piperidin-1-yl)-1,4-dihydropyrimidine-5-carbonyl)-2-thioxochroman-4-one 16 and/or 4'-(1H-indol-3-yl)-2-mercapto-6'-methyl-6-(methylthio)-2'-thioxo-1',2',3',4'-tetrahydro-[4,5'-bipyrimidine]-5-carbaldehyde 18. The newly synthesized compounds have been in vitro examined as antimicrobial agents, and some of them showed a promising activity. All newly synthesized compounds have been characterized by means of elemental analyses, IR, 1 H-NMR and MS.

Synthesis and Reactivity of 3H-1,2-dithiole-3-thiones

“…Later on, it was shown that for some heterocyclic acetyl derivatives KH can be replaced by potassium tert-butoxide and hexamethyldisilathiane by P 2 S 5 (Scheme 6). In these cases, the yields may vary from good to low [37,38]. Unfortunately, it is still unclear whether this method is applicable to other ketones.…”

A comprehensive review on synthesis of dihydropyrimidione via Biginelli reaction catalyzed by reusable magnetic nanocatalyst (from 2020–till date)

“…Strong acidic conditions in a protic solvent [118,119] 2. Lewis's acids; strong Bronsted acids [120,121] 3.…”