- Synthesis of isothiocyanates using DMT/NMM/TsO? as a new desulfurization reagent
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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 (Et3 N, 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.
- Janczewski, ?ukasz,Kolesińska, Beata,Kr?giel, Dorota
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- Direct, Microwave-Assisted Synthesis of Isothiocyanates
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A microwave-assisted desulfuration of readily available dithiocarbamates, formed in situ from primary amines, leading to target isothiocyanates has been developed. This efficient protocol provides a rapid, environmentally benign route to aliphatic and aromatic isothiocyanates.
- Janczewski, ?ukasz,Gajda, Anna,Gajda, Tadeusz
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p. 2528 - 2532
(2019/04/03)
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- T3P - A Benign Desulfurating Reagent in the Synthesis of Isothiocyanates
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A number of alkyl, aryl and bifunctional isothiocyanates are obtained in moderate to high yields (41-94%) in a two-step, one-pot reaction of the parent primary amines or their salts with carbon disulfide, followed by reaction of the thus formed dithiocarbamates with T3P (propane phosphonic acid anhydride) as a new and efficient desulfurating agent.
- Janczewski, ?ukasz,Gajda, Anna,Frankowski, Sebastian,Goszczyński, Tomasz M.,Gajda, Tadeusz
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p. 1141 - 1151
(2017/12/06)
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- 2,4,4,6-Tetrabromo-2,5-cyclohexadienone as an efficient reagent for phosphine-free electrophilic transformation of alcohols and epoxides
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In this study, 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO) was prepared and used successfully as a stable phosphine-free reagent for the conversion of alcohols into alkyl thiocyanates and epoxides into 2-hydroxythiocyanates. The reactions seem to proceed via in situ generation of electrophilic sulfur species by reaction of NH4SCN and TABCO. This combined reagent worked well with both alcohols and epoxides in acetonitrile solvent and under solvent-free conditions.
- Khajeh-Kolaki, Aslan,Mokhtari, Babak
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p. 251 - 258
(2016/06/01)
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- Chlorodiphenylphosphine as highly selective and efficient reagent for the conversion of alcohols, tetrahydropyranyl and silyl ethers to thiocyanates and isothiocyanates
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(Equation present) A simple, highly selective and efficient method is described for the conversion of primary alcohols, tetrahydropyranyl and silyl ethers to thiocyanates by use of chlorodiphenylphosphine and ammonium thiocyanate. Secondary substrates produce both the two isomeric products, thiocyanate and isothiocyanate, while tertiary ones give isothiocyanates as the only products by this new method. In contrast to previously reported methods based on trivalent phosphorus for this transformation, the present method does not require an electrophile in the presence of trivalent phosphorus (ClPPh 2). The order of activity of these substrates is silyl ether> alcohol > tetrahydropyranyl ether. The present method not only interestingly distinguishes between primary, secondary and tertiary substrates but also converts them to the corresponding thiocyanates with excellent chemoselectivity in the presence of several other functional groups. 2014 Copyright Taylor & Francis Group, LLC.
- Aghapour, Ghasem,Asgharzadeh, Ameneh
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p. 796 - 802
(2014/07/08)
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- Heterogeneous thiocyanation of benzylic alcohols and silyl and THP ethers, and deprotection of silyl and THP-ethers by [PCl3-n(SiO 2)n] (silphos)
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Silicaphosphite (silphos), [PCl3-n(SiO2) n], as a heterogeneous phosphorous compound, catalyzes the thiocyanation of benzylic alcohols and silyl and THP ethers in the presence of I2 and NH4SCN in refluxing CH3CN. The produced silphos oxide byproduct can be easily separated by a simple filtration. Silphos is also used for the efficient and selective deprotection of silyl and THP-ethers to their corresponding alcohols. Copyright
- Iranpoor,Firouzabadi,Bahador,Jamalian
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experimental part
p. 1972 - 1978
(2010/11/16)
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- 4-Aminophenyl diphenylphosphinite (APDPP) as a heterogeneous and acid scavenger reagent for thiocyantion or isothiocyanation of alcohols and protected alcohols
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4-Aminophenyl diphenylphosphinite (APDPP) as a heterogeneous phosphinite reagent is used for the efficient conversion of alcohols, trimethylsilyl- and tetrahydropyranyl ethers, α-hydroxy phosphonates, and - trimethylsilyloxyphosphonates to their corresponding thiocyanates or isothiocyanates in the presence of Br2 and NH4SCN.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
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experimental part
p. 2010 - 2019
(2010/03/24)
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- Preparation of thiocyanates and isothiocyanates from alcohols, thiols, trimethylsilyl-, and tetrahydropyranyl ethers using triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)/n-Bu4NSCN system
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A combination of triphenylphosphine (PPh3) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) provides a safe and easily available mixed reagent system for the conversion of 1° and 2° alcohols, thiols, trimethylsilyl-, and tetrahydropyranyl ethers to their corresponding thiocyanates and the 3° ones to isothiocyanates in good to high yields.
- Iranpoor, Nasser,Firouzabadi, Habib,Nowrouzi, Najmeh
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p. 5498 - 5501
(2007/10/03)
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- A new diphenylphosphinite ionic liquid (IL-OPPh2) as reagent and solvent for highly selective bromination, thiocyanation or isothiocyanation of alcohols and trimethylsilyl and tetrahydropyranyl ethers
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A new diphenylphosphinite ionic liquid (IL-OPPh2) is introduced. This ionic liquid is used as both a reagent and a solvent to convert alcohols and trimethylsilyl and tetrahydropyranyl (THP) ethers into their corresponding alkyl bromides, thiocyanates or isothiocyanates in the presence of Br2 and SCN- at 80 °C. In this ionic liquid, bromination and thiocyanation of alcohols occurs highly selectively in the presence of trimethylsilyl and THP-ethers and also between different classes of alcohols. The use of this ionic liquid allows easy separation of the desired products from the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Azadi, Roya
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p. 5531 - 5534
(2007/10/03)
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- Efficient conversion of tetrahydropyranyl (THP) ethers to their corresponding thiocyanates with in-situ-generated Ph3P(SCN) 2
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Immediate and efficient one-pot conversion of tetrahydropyranyl (THP) ethers to their corresponding thiocyanates by in-situ-generated Ph 3P(SCN)2 is described. Primary and secondary alkyls and also benzylic THP ethers are converted to their corresponding thiocyanates in excellent yields at room temperature by this method. Copyright Taylor & Francis Inc.
- Iranpoor, Nasser,Firouzabadi, Habib,Shaterian, Hamid Reza
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p. 2093 - 2096
(2007/10/03)
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- Preparation of alkyl nitrates, nitrites, and thiocyanates from alcohols utilizing trichloroisocyanuric acid with triphenylphosphine
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Alcohols in acetonitrile are converted into alkyl nitrates, nitrites, or thiocyanates by the action of triphenylphosphine and trichloroisocyanuric acid along with silver nitrate, silver nitrite, or sodium thiocyanate, respectively.
- Hiegel, Gene A.,Nguyen, Jeremiah,Zhou, Yan
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p. 2507 - 2511
(2007/10/03)
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- Efficient one-pot thiocyanation of primary, secondary and tertiary alcohols by in situ generation of Ph3P(SCN)2. A modified procedure
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The preparation of Ph3P(SCN)2 is modified by using a combination of Ph3P, NH4SCN and Br2 at room temperature for the efficient conversion of primary, secondary and tertiary alcohols to their corresponding thiocyanates in excellent yields.
- Iranpoor,Firouzabadi,Shaterian
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p. 676 - 677
(2007/10/03)
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- SYNTHESIS OF ISOTHIOCYANATOPHOSPHORANES AND ISOTHIOCYANATOPHOSPHONIUM SALTS VIA OXIDATIVE ADDITION OF THIOCYANOGEN AND LIGAND SUBSTITUTION. NOVEL REAGENTS FOR CONVERTING HYDROXY GROUPS INTO THIOCYANATE AND ISOTHIOCYANATE FUNCTIONS UNDER MILD CONDITIONS
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The oxidative addition of thiocyanogen to triphenilphosphine has been investigated by (31)P NMR spectroscopy showing the formation of the isothiocyanatophosphonium salt 8.The analogous reaction between thiocyanogen and alkyl o-phenylene phosphites 7 leads to diisothiocyanatophosphoranes 9.The same products were prepared via ligand substitution from the corresponding chlorophosphonium salt 12 and alkyldichloro-o-phenylene phosphoranes 13 by the action of potassium thiocyanate in the presence of 18-crown-6-ether or more conveniently using lead thiocyanate.The phosphonium salt 8 and phosphoranes 9 were employed as convenient novel reagents for converting hydroxy groups into thiocyanate and isothiocyanate function with high stereoselectivity under very mild conditions.The efficient synthesis of acylisothiocyanates RCONCS,R2P(O)NCS and R2P(S)NCS via addition of thiocyanogen to mixed anhydrides is of special interest.
- Burski, J.,Kieszkowski, J.,Michalski, J.,Pakulski, M.,Skowronska, A.
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p. 4175 - 4182
(2007/10/02)
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