New synthesis of 1,2,4-thiadiazoles

Lin, Yang‐I; Lang, S. A.; Petty, Sharon R.

doi:10.1021/jo01307a006

Cited by 46 publications

(18 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3. Nicotinamide (1m) was reacted with dimethyl acetal of N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAc) to give N-(3-pyridylcarbonyl)amidines (2m-1, 2), which were cyclized with hydroxylamine-O-sulfonic acid (HOSA), 11) giving 5-(3-pyridyl)-1,2,4-oxadiazoles (3m-1, 2) in low yield. In contrast, the cyclization reaction using hydroxylamine instead of HOSA gave the desired products (3m-1, 2) in more than 78% yield.…”

Section: General Proceduresmentioning

confidence: 99%

“…5 shows the synthesis route of 5-(1,2,5,6-tetrahydropyridin-3-yl)-1,2,4-thiadiazoles (9m-1-10) and their intermediates (7m, 8m). 5-(3-Pyridyl)-1,2,4-thiadiazoles (7m-1, 2) were synthesized by an oxidative cyclization reaction 11) of HOSA with N-(3-pyridylthiocarbonyl)amidines, which were easily prepared by condensation of thionicotinamide (6m) with dimethyl acetal of DMF or DMAc. Quaternization of 7m with several alkyl halides followed by reduction with sodium borohydride gave the desired 5-(1,2,5,6-tetrahydro-1-alkylpyridin-3-yl)-1,2,4-thiadiazoles (9m-1-10).…”

Section: General Proceduresmentioning

confidence: 99%

“…Following the synthesis methods for 1,2,4-oxadiazoles (5m), 5-(1,2,5,6-tetrahydropyridin-3-yl)-1,2,4-thiadiazoles (9m-1-10) were also synthesized, provided 5-(3-pyridyl)-1,2,4-thiadiazoles (7m-1, 2) prepared by an oxidative cyclization reaction 11) of N-(3-pyridylthiocarbonyl)amidines with HOSA (Fig. 5).…”

Section: Synthesismentioning

confidence: 99%

See 2 more Smart Citations

Synthesis and insecticidal activity of 1,2,4-oxadiazole and 1,2,4-thiadiazole derivatives

et al. 2011

View full text Add to dashboard Cite

A series of 5-substituted 1,2,4-oxadiazoles and 1,2,4-thiadiazoles were prepared as muscarinic acetylcholine receptor agonists and evaluated for their insecticidal activity. These derivatives were synthesized through sequential reactions consisting of the condensation of pyridinecarboamides or pyridinecarbothioamides with N,N-dimethylacetamide dimethyl acetal, cyclization with hydroxylamine, quaternization by alkyl halide and reaction with sodium borohydride. All 1,2,4-oxadiazoles and 1,2,4-thiadiazoles synthesized were evaluated for insecticidal activity and their structure-activity relationships are discussed. It was discovered that many compounds were active against representative insects such as Nilaparvata lugens, Nephotettix cincticeps and Aphis craccivora. In particular, it was also found that 3-pyridyl-substituted derivatives of 1,2,4-oxadiazole and 1,2,4-thiadiazole exhibited good insecticidal activity against all the insects tested. Among the compounds evaluated, 3-methyl-5-(1,2,5,6-tetrahydropyridin-3-yl)-1,2,4-thiadiazole (9m-2) showed the highest activity against Nilaparvata lugens, and provided a high level of activity against the imidacloprid-resistant strain. Based on the preliminary binding assay using the binding inhibition of mAChR antagonist [ 3 H]NMS to the nerve-cord membranes as an index of the binding activity, 9m-2 exhibited a range of potencies for the insect muscarinic receptor.

show abstract

Section: General Proceduresmentioning

confidence: 99%

Section: General Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and insecticidal activity of 1,2,4-oxadiazole and 1,2,4-thiadiazole derivatives

et al. 2011

View full text Add to dashboard Cite

show abstract

“…1 H NMR spectral data on several 1,2,4-thiadiazole derivatives have been reported [126,153,154,158]. In general, the resonances of protons in the 1,2,4-thiadiazoles are shifted downfield with respect to benzene protons, with the proton at C3 more deshielded than the proton at C5.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Thiadiazoles

Chiacchio

Romeo

2011

Modern Heterocyclic Chemistry

View full text Add to dashboard Cite

“…Starting Materials. All thiocarbonyl derivatives and their precursors, and all diazo compounds were prepared according to known protocols: diazomethane (3a) [15], diazo(diphenyl)methane (3b) [16], diazocyclohexane (3c) [17], diazo(phenyl)methane (3d) [18], N-[(dimethylamino)methylidene]thiobenzamide (8) [19], 2-(dimethylhydrazono)-1-phenylethane-1-thione (9) [20] [21]. All other reagents are commercially available.…”

mentioning

confidence: 99%

1,5‐Dipolar Electrocyclizations of Thiocarbonyl Ylides Bearing CN Groups: Reactions of N‐[(Dimethylamino)methylene]thiobenzamide and 2‐(Dimethylhydrazono)‐1‐phenylethane‐1‐thione with Diazo Compounds

Egli

Linden

Heimgartner

2007

Helvetica Chimica Acta

View full text Add to dashboard Cite

The reactions of thiobenzamide 8 with diazo compounds proceeded via reactive thiocarbonyl ylides as intermediates, which underwent either a 1,5-dipolar electrocyclization to give the corresponding five membered heterocycles, i.e., 4-amino-4,5-dihydro-1,3-thiazole derivatives (i.e., 10a, 10b, 10c, cis-10d, and trans-10d) or a 1,3-dipolar electrocyclization to give the corresponding thiiranes as intermediates, which underwent a S N i'-like ring opening and subsequent 5-exo-trig cyclization to yield the isomeric 2-amino-2,5-dihydro-1,3-thiazole derivatives (i.e., 11a, 11b, 11c, cis-11d, and trans-11d). In general, isomer 10 was formed in higher yield than isomer 11. In the case of the reaction of 8 with diazo(phenyl)methane (3d), a mixture of two pairs of diastereoisomers was formed, of which two, namely cis-10d and trans10d, could be isolated as pure compounds. The isomers cis-11d and trans-11d remained as a mixture. In the reactions of the thioxohydrazone 9 with diazo compounds 3b and 3d, the main products were the alkenes 18 and 23, respectively. Their formation was rationalized by a 1,3-dipolar electrocyclization of the corresponding thiocarbonyl ylide and subsequent desulfurization of the intermediate thiiran. As minor products, 2,5-dihydro-1,3-thiazol-5-amines 21 and 24 were obtained, which have been formed by 1,5-dipolar electrocyclization of the thiocarbonyl ylide, followed by a 1,3-shift of the dimethylamino group.1. Introduction. -The concept of the 1,5-dipolar electrocyclization as a tool for the synthesis of five-membered heterocycles has been proposed 25 years ago [1] [2]. Since, we have shown that thiocarbonyl ylides, which bear a C=O group at the C(a)-atom, undergo this cyclization to give 1,3-oxathioles [3] [4] (see also [5] [6]). These thiocarbonyl ylides were generated in situ by the reaction of thiocarbonyl derivatives with a-diazo carbonyl compounds. Very recently, we reported on the reaction of a-thioxocarbonyl derivatives with diazo compounds [7]. We were mostly interested in systems, in which the conjugated p-system consisted of a C=O or a C=S group, i.e., in reactions of a-thioxo ketone 1 and a-thioxo thioamide 2 (Scheme 1).The reactions with diazo compounds 3 all followed the same pathway: 1,3-dipolar cycloaddition to give a 2,5-dihydro-1,3,4-thiadiazole, N 2 elimination by cycloreversion to produce thiocarbonyl ylides 4, and 1,5-dipolar electrocyclization. The resulting products are either 1,3-oxathioles 5 or 1,3-dithioles 6, respectively. Some thiirane side products, which were formed by a competing 1,3-dipolar electrocyclization, were unstable, and elimination of sulfur led to the corresponding alkenes, e.g., 7.

show abstract

New synthesis of 1,2,4-thiadiazoles

Cited by 46 publications

References 2 publications

Synthesis and insecticidal activity of 1,2,4-oxadiazole and 1,2,4-thiadiazole derivatives

Synthesis and insecticidal activity of 1,2,4-oxadiazole and 1,2,4-thiadiazole derivatives

Thiadiazoles

1,5‐Dipolar Electrocyclizations of Thiocarbonyl Ylides Bearing CN Groups: Reactions of N‐[(Dimethylamino)methylene]thiobenzamide and 2‐(Dimethylhydrazono)‐1‐phenylethane‐1‐thione with Diazo Compounds

Contact Info

Product

Resources

About