A metal-free and a solvent-free synthesis of thio-amides and amides: an efficient Friedel–Crafts arylation of isothiocyanates and isocyanates

Varun, Begur Vasanthkumar; Sood, Ankush; Prabhu, Kandikere Ramaiah

doi:10.1039/c4ra12944j

Cited by 26 publications

(12 citation statements)

References 84 publications

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“…13 C NMR (100 MHz, CDCl 3 ): δ=124.4 (+, 2C), 124.8 (+, 1C), 127.2 (+, 1C), 128.1 (+, 1C), 129.2 (+, 2C), 133.2 (+, 1C), 138.6 (o, 1C), 148.1 (o, 1C), 188.0 (o, 1C) ppm. The data are in agreement with those reported in the literature [38] …”

Section: Methodssupporting

confidence: 93%

“…in 30 mL of anhydrous toluene was stirred at reflux temperature for 4 h. After removal of the solvent in vacuo , the crude product was chromatographed (PE:EE, 5 : 1). Yield: 1.950 g (8.90 mmol, 98 %), green solid, mp 93–95 °C [38] . 1 H NMR (400 MHz, CDCl 3 ): δ=7.09 (dd, J H,H =5.1, 4.0 Hz, 1H), 7.27–7.31 (m, 1H), 7.39‐7.44 (m, 2H), 7.52 (bs, 1H), 7.54 (dd, J H,H =5.1, 1.0 Hz, 1H), 7.67 (d, J H,H =7.8 Hz, 2H), 8.98 (bs, 1H) ppm.…”

Section: Methodsmentioning

confidence: 99%

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1,3‐Thiazolium‐4‐aminides: Syntheses and Characterization of Fluorescent Mesoionic Compounds

et al. 2021

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A series of mesoionic 1,3‐thiazolium‐4‐aminides was synthesized starting from thioamides and chloroacetonitrile via cyanomethylbenzimidothioates which were cyclized by benzoylchloride. Depending on the reaction conditions 4‐amino‐1,3‐thiazolium salts and 4‐N‐benzamido‐1,3‐thiazolium salts were obtained (X‐ray structure analysis). Substitution of the amino groups with benzoyl chloride gave a series of the title mesoionic compounds (X‐ray structure analysis) which were examined spectroscopically. Negative solvatochromism was found and temperature‐dependent as well as time‐resolved fluorescence measurements were made. Long lifetimes of the excited states (30–50 ns) were detected. Calculated frontier orbital profiles gain insight into the characteristics of 1,3‐thiazolium‐4‐aminides as conjugated mesomeric betaines.

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Section: Methodssupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

1,3‐Thiazolium‐4‐aminides: Syntheses and Characterization of Fluorescent Mesoionic Compounds

et al. 2021

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“…Friedel–Crafts-type reaction of arenes with isothiocyanates constitutes a useful method for the synthesis of aromatic secondary thioamides [ 1 – 6 ]. Our group [ 7 ] and others [ 8 ] have recently described an efficient modification of this method by using trifluoromethanesulfonic (triflic) acid as a promoter. Furthermore, we reported a simple procedure for the oxidative desulfurization of thioamides to amides via reaction with Oxone ® .…”

Section: Introductionmentioning

confidence: 99%

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

Wrona-Piotrowicz

Gajda

et al. 2015

Beilstein J. Org. Chem.

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SummaryFriedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates promoted by trifluoromethanosulfonic acid afforded diethyl 1-(pyrene-1-carbothioamido)alkylphosphonates in 83–94% yield. These compounds were transformed, in 87–94% yield, into the corresponding diethyl 1-(pyrene-1-carboxamido)alkylphosphonates by treatment with Oxone®. 1-(Pyrene-1-carboxamido)methylphosphonic acid was obtained in a 87% yield by treating the corresponding diethyl phosphonate with Me3Si-Br in methanol. All of the synthesized amidophosphonates were emissive in solution and in the solid state. The presence of a phosphonato group brought about an approximately two-fold increase in solution fluorescence quantum yield in comparison with that of a model N-alkyl pyrene-1-carboxamide. This effect was tentatively explained by stiffening of the amidophosphonate lateral chain which was caused by the interaction (intramolecular hydrogen bond) of phosphonate and amide groups. The synthesized phosphonic acid was soluble in a biological aqueous buffer (PBS, 0.01 M, pH 7.35) and was strongly emissive under these conditions (λem = 383, 400 nm, τ = 18.7 ns, ΦF > 0.98). Solid-state emission of diethyl 1-(pyrene-1-carboxamido)methylphosphonate (λmax = 485 nm; ΦF = 0.25) was assigned to π–π aggregates, the presence of which was revealed by single-crystal X-ray diffraction analysis.

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“…Natural as well as synthetic ITCs may additionally have anti-bacterial [ 27 , 28 , 29 , 30 ], anti-fungal [ 31 ], and anti-glioblastoma effects [ 32 ]. They are used in proteomics as probes [ 33 , 34 ], and in organic synthesis for the preparation of thioureas [ 35 ], thioamides [ 36 ], and heterocyclic compounds [ 37 , 38 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Isothiocyanates Using DMT/NMM/TsO− as a New Desulfurization Reagent

2021

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Thirty-three alkyl and aryl isothiocyanates, as well as isothiocyanate derivatives from esters of coded amino acids and from esters of unnatural amino acids (6-aminocaproic, 4-(aminomethyl)benzoic, and tranexamic acids), were synthesized with satisfactory or very good yields (25–97%). Synthesis was performed in a “one-pot”, two-step procedure, in the presence of organic base (Et3N, DBU or NMM), and carbon disulfide via dithiocarbamates, with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate (DMT/NMM/TsO−) as a desulfurization reagent. For the synthesis of aliphatic and aromatic isothiocyanates, reactions were carried out in a microwave reactor, and selected alkyl isothiocyanates were also synthesized in aqueous medium with high yields (72–96%). Isothiocyanate derivatives of L- and D-amino acid methyl esters were synthesized, under conditions without microwave radiation assistance, with low racemization (er 99 > 1), and their absolute configuration was confirmed by circular dichroism. Isothiocyanate derivatives of natural and unnatural amino acids were evaluated for antibacterial activity on E. coli and S. aureus bacterial strains, where the most active was ITC 9e.

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A metal-free and a solvent-free synthesis of thio-amides and amides: an efficient Friedel–Crafts arylation of isothiocyanates and isocyanates

Cited by 26 publications

References 84 publications

1,3‐Thiazolium‐4‐aminides: Syntheses and Characterization of Fluorescent Mesoionic Compounds

1,3‐Thiazolium‐4‐aminides: Syntheses and Characterization of Fluorescent Mesoionic Compounds

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

Synthesis of Isothiocyanates Using DMT/NMM/TsO− as a New Desulfurization Reagent

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