Synthesis of N-(hydroxymethylene)thioamides by N-hydroxymethylation of 2-cyanothioacrylamides

The condensation products of cyanothioacetamide with aldehydes—(E)-arylmethylenecyanothioacetamides—have proven to be readily available and multifunctional starting reagents in the chemistry of S,N-containing compounds. We decided to study the interaction of formaldehyde with thioamides as a possible way to obtain N-(hydroxymethylene)thioamides, which are promising thioamidoalkylating agents and new ligands for complexation. It was found that the reaction of thioamides and formaldehyde proceeds easily when the reagents are heated in the absence of catalysts in an aqueous-alcohol medium, and leads, with good yields, to the expected N-(hydroxymethylene)thioamides. The structure of N-(hydroxymethylene)thioamides 2 was confirmed by IR and NMR spectroscopy data

Radziszewski-Type Oxidation of 3,5-di(α-cyanostyryl)-1,2,4-thiadiazoles

Due to the presence of two acrylonitrile fragments, 3,5-di(α-cyanostyryl)-1,2,4-thiadiazoles are prone to react under Radziszewski reaction conditions (oxidative hydrolysis of nitriles to amides) with the simultaneous epoxidation and formation of epoxyamides. We found that the reaction proceeds in a non-selective way and yields a mixture of products of regioisomeric oxidation. Only in one case we succeeded to isolate the product of double epoxidation. The structure of the epoxyamides products was confirmed by IR and NMR spectroscopy data

The Reactions of N,N′-Diphenyldithiomalondiamide with Arylmethylidene Meldrum’s Acids

The Michael addition reaction between dithiomalondianilide (N,N′-diphenyldithiomalondiamide) and arylmethylidene Meldrum’s acids, accompanied by subsequent heterocyclization, was investigated along with factors affecting the mixture composition of the obtained products. The plausible mechanism includes the formation of stable Michael adducts which, under the studied conditions, undergo further transformations to yield corresponding N-methylmorpholinium 4-aryl-6-oxo-3-(N-phenylthio-carbamoyl)-1,4,5,6-tetrahydropyridin-2-thiolates and their oxidation derivatives, 4,5-dihydro-3H-[1,2]dithiolo[3,4-b]pyridin-6(7H)-ones. The structure of one such product, N-methylmorpholinium 2,2-dimethyl-5-(1-(2-nitrophenyl)-3-(phenylamino)-2-(N-phenylthiocarbamoyl)-3-thioxopropyl)-4-oxo-4H-1,3-dioxin-6-olate, was confirmed via X-ray crystallography

Alkyl 4-Aryl-6-amino-7- phenyl-3-(phenylimino)-4,7-dihydro- 3H-[1,2]dithiolo[3,4-b]pyridine-5-carboxylates: Synthesis and Agrochemical Studies

The reaction between dithiomalondianilide (N,N’-diphenyldithiomalondiamide) and alkyl 3-aryl-2-cyanoacrylates in the presence of morpholine in the air atmosphere leads to the formation of alkyl 6-amino-4-aryl-7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]- pyridine-5-carboxylates in 37–72% yields. The same compounds were prepared in 23–65% yields by ternary condensation of aromatic aldehydes, ethyl(methyl) cyanoacetate and dithiomalondianilide. The reaction mechanism is discussed. The structure of ethyl 6-amino-4-(4-methoxyphenyl)-7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]pyridine-5-carboxylate was confirmed by X-ray crystallography. Two of the prepared compounds showed a moderate growth-stimulating effect on sunflower seedlings. Three of the new compounds were recognized as strong herbicide safeners with respect to herbicide 2,4-D in the laboratory and field experiments on sunflower