New synthesis of 3,5-disubstituted-5H-thiazolo[3,2-a]pyrimidine via ring annulation of 3,4-dihydropyrimidin-2(1H)-thione using alkynyl(aryl)iodonium salts

Shelke, Amol V.; Bhong, Bhagyashree Y.; Karade, Nandkishor N.

doi:10.1016/j.tetlet.2012.11.098

Cited by 16 publications

(6 citation statements)

References 43 publications

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“…Reaction pentachloropyridine with (benzylidene)‐4‐(2‐aryl)‐3,4,5,6,7,8‐hexahydroquinazoline‐2(1 H )‐thione/(benzylidene)‐4‐(2‐aryl)‐3,4,6,7‐tetrahydro‐1 H ‐cyclopenta[ d ]pyrimidine‐2(5 H ) thione affords the intermediate thioether A , which, on intermolecular cyclization, followed by the nucleophilic attack of nitrogen atom of pyrimidinethiones on electrophilic chlorine of 2 , affords the title compounds .…”

Section: Resultsmentioning

confidence: 99%

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

Darehkordi

Fazli‐Zafarani

Kamali

2017

Journal of Heterocyclic Chem

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in Wiley Online Library (wileyonlinelibrary.com).An efficient one-pot method for synthesis of new biologically active thiazolo[3,2-a]pyrimidine and thiazolo[2,3-b]quinazoline derivatives is described via reaction of pentachloropyridine with fused pyrimidine-2(5H)-thiones or quinazoline-2(1H)-thiones. These reactions were carried out in the presence of potassium carbonate as a base in acetonitrile as a solvent to produce products 3a-n in good-toexcellent yield. Pentachloropyridine is doubly electrophilic building blocks for the formation of ring annulated thiazolo[3,2-a]pyrimidine and thiazolo[2,3-b]quinazoline products.Scheme 2. A plausible mechanism for synthesis of the fused thiazolo[3,2-a]pyrimidines and thiazolo[2,3-b]quinazolines.

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Section: Resultsmentioning

confidence: 99%

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

Darehkordi

Fazli‐Zafarani

Kamali

2017

Journal of Heterocyclic Chem

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“…Furthermore, copper catalysed C−S coupling reaction for the formation of thiazolo[3,2‐a]pyrimidine derivatives from 3,4‐dihydropyrimidin‐2(1 H )‐thiones with terminal alkynes has also been achieved by Sun group . Later, Karade reported a novel and transition metal‐free protocol for the synthesis of thiazolo[3,2‐a]pyrimidine derivatives by K 2 CO 3 ‐mediated cyclization of 3,4‐dihydropyrimidin‐2(1 H )‐thiones with alkynyl(aryl)iodonium tosylates. However, to the best of knowledge, there is no report in describing the synthesis of thiazolo[3,2‐a]pyrimidine derivatives involving KI/K 2 S 2 O 8 ‐mediated C−S/C−N bond formation of enaminones with 3,4‐dihydropyrimidin‐2(1 H )‐thiones.…”

Section: Methodsmentioning

confidence: 99%

KI/K₂S₂O₈‐Mediated C‐S/C‐N Bond Formation: One‐Pot Regioselective Synthesis of 5H‐Thiazolo[3,2‐a]pyrimidines

Yang

Liu

et al. 2019

ChemistrySelect

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A new strategy for the synthesis of 5H-thiazolo[3,2-a]pyrimidines from KI/K 2 S 2 O 8 mediated CÀ S and CÀ N bond tandem cyclization reaction of enaminones with 3,4-dihydropyrimidin-2(1H)-thiones has been developed. This method features inexpensive catalyst, base free and transition-metal free with simple procedure, affording the desired products in moderate to excellent yields.As one of the most important heterocyclic compounds, thiazolo[3,2-a]pyrimidines not only have been found in wide range of natural products but also have exhibited a wide range of diverse pharmacological activities in medical chemistry, such as anti-inflammatory, antimicrobial, anticancer, antitumor, antibacterial, antiparkinsonian, antinociceptive, and antiviral. [1] In view of their diverse activities, a number of synthetic methods for the synthesis of thiazolo[3,2-a]pyrimidines have been developed over the years. In general, thiazolo[3,2-a]pyrimidine derivatives are synthesized by typical methods including the cyclization of halides such as chloroacetic acid, [2] 2-bromoketones, [3] chloroacetyl chloride, [4] methyl chloroacetate, [5] and 1,2-dichloroethane [6] with 3,4-dihydropyrimidin-2(1H)-thiones. Recently, Singh [7] developed an efficient one-pot method to synthesize thiazolo[3,2-a]pyrimidine derivatives from 3,4-dihydropyrimidin-2(1H)-thiones with in-situ generated bromo-ketones received by reaction of different α-H carbonyl compounds with bromine. Furthermore, copper catalysed CÀ S coupling reaction for the formation of thiazolo[3,2-a]pyrimidine derivatives from 3,4-dihydropyrimidin-2(1H)-thiones with terminal alkynes has also been achieved by Sun group. [8] Later, Karade [9] reported a novel and transition metal-free protocol for the synthesis of thiazolo[3,2-a]pyrimidine derivatives by K 2 CO 3mediated cyclization of 3,4-dihydropyrimidin-2(1H)-thiones with alkynyl(aryl)iodonium tosylates. However, to the best of knowledge, there is no report in describing the synthesis of thiazolo[3,2-a]pyrimidine derivatives involving KI/K 2 S 2 O 8 -mediated CÀ S/CÀ N bond formation of enaminones with 3,4dihydropyrimidin-2(1H)-thiones.

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“…The synthesis of thiazolo [3,2-a]pyrimidine was achieved by the reaction of 4-aryl-3,4-dihydropyrimidin-2(1H)-thione and phenyl(phenylethyny1)iodonium tosylate in K 2 CO 3 as a base in the THF medium (Scheme 1) [ 21 ]. The compound was recrystallized by slow evaporation of a petroleum ether-ethyl acetate solution (3:1) yielding light yellow single crystals suitable for X-ray diffraction.…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

CRYSTAL STRUCTURE, DFT STUDY, AND HIRSHFELD SURFACE ANALYSIS OF ETHYL 5-(3,4-DIMETHOXYPHENYL)-7-METHYL-3-PHENYL-5H-THIAZOLO[3,2-a]PYRIMIDINE-6-CARBOXYLATE

2015

JSC

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The structural characterization of fused thiazolopyrimidine 1 (C 24 H 24 N 2 O 4 S) is performed using the single crystal X-ray study, the DFT calculation, and the Hirshfeld surface analysis. The molecular packing of the crystal is mainly stabilized by C-H…O and C-H…S interactions. A DFT calculated HOMO-LUMO energy gap of 3.90 eV indicates a high kinetic stability of the compound. The 3D Hirshfeld surfaces and the associated 2D fingerprint plots are investigated for short contact interactions. The relative contribution of different interactions to the Hirshfeld surface indicates that the H…H, C…H, and O…H contacts account for about 83.4 % of the total Hirshfeld surface area.

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New synthesis of 3,5-disubstituted-5H-thiazolo[3,2-a]pyrimidine via ring annulation of 3,4-dihydropyrimidin-2(1H)-thione using alkynyl(aryl)iodonium salts

Cited by 16 publications

References 43 publications

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

KI/K₂S₂O₈‐Mediated C‐S/C‐N Bond Formation: One‐Pot Regioselective Synthesis of 5H‐Thiazolo[3,2‐a]pyrimidines

CRYSTAL STRUCTURE, DFT STUDY, AND HIRSHFELD SURFACE ANALYSIS OF ETHYL 5-(3,4-DIMETHOXYPHENYL)-7-METHYL-3-PHENYL-5H-THIAZOLO[3,2-a]PYRIMIDINE-6-CARBOXYLATE

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New synthesis of 3,5-disubstituted-5H-thiazolo[3,2-a]pyrimidine via ring annulation of 3,4-dihydropyrimidin-2(1H)-thione using alkynyl(aryl)iodonium salts

Cited by 16 publications

References 43 publications

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

KI/K2S2O8‐Mediated C‐S/C‐N Bond Formation: One‐Pot Regioselective Synthesis of 5H‐Thiazolo[3,2‐a]pyrimidines

CRYSTAL STRUCTURE, DFT STUDY, AND HIRSHFELD SURFACE ANALYSIS OF ETHYL 5-(3,4-DIMETHOXYPHENYL)-7-METHYL-3-PHENYL-5H-THIAZOLO[3,2-a]PYRIMIDINE-6-CARBOXYLATE

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KI/K₂S₂O₈‐Mediated C‐S/C‐N Bond Formation: One‐Pot Regioselective Synthesis of 5H‐Thiazolo[3,2‐a]pyrimidines