Conversion of Alcohols, Thiols, Carboxylic Acids, Trimethylsilyl Ethers, and Carboxylates to Thiocyanates with Triphenylphosphine/Diethylazodicarboxylate/NH4SCN (original) (raw)
ChemInform, 2006
A combination of triphenylphosphine (PPh 3) 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.
Conversion of Alcohols, Thiols, and Trimethysilyl Ethers to AlkyCyanides Using Triphenylphosphine
Journal of Organic Chemistry, 2004
Triphenylphosphine and 2,3-dichloro-5,6-dicyanobenzoquinone afford an adduct, which in the presence of n-Bu 4 NCN converts alcohols, thiols, and trimethylsilyl ethers into their corresponding alkyl cyanides in good to excellent yields at room temperature. This method is highly selective for the conversion of 1°alcohols in the presence of 2°and 3°ones, thiols and silyl ethers.
ChemInform, 2003
The introduction and removal of functional groups is of great importance in the synthesis of polyfunctional organic molecules. The conversion of thiocarbonyls to their corresponding carbonyl compounds is an important chemical transformation. Various methods and reagents have been reported for the deprotection of thiocarbonyl compounds to their oxygen analogues. However, some of these methods are not suitable for deprotection of primary thioamides, and some of the others also show limitations such as long reaction times, low yields of the products, use of expensive reagents and tedious work-up. We have recently reported bismuth(III) nitrate pentahydrate and oxone as convenient reagents for the deprtection of thioamides and thioureas. 22 Bismuth(III) nitrate pentahydrate was not effective for transformation of thiono esters and thioketones to their corresponding esters and ketones. However, with oxone thiono esters are converted to their esters while thioketones remained intact in the presence of this reagent. In continuation of our ongoing work in this area, we were interested to find an efficient method for the deprotection of all the above mentioned thiocarbonyl compounds.
Journal of the American Chemical Society, 2009
Materials. Propargyl acrylate, hexylamine, captopril, thiocholesterol, 6-mercaptohexanol, butyl 3-mercaptopropionate, thioglycerol, 3-(mercaptopropyl)trimethoxysilane, and thiomalic acid were purchased from Aldrich Chemical Co. 3-Mercaptopropyl isobutyl POSS ® was purchased from Hybrid Plastics. Pentaerythritol tetramercaptoprionate was donated by Bruno Bock (purity > 83%). All solvents and reagents were used as received. Synthesis of the 4-functional alkyne (14). Pentaerythritol tetramercaptoprionate (2.44 g, 5 mmol) was mixed with hexylamine (30μL, ~1 mol%). To this mixture was added propargyl acrylate (2.20 g, 20 mmol). The reaction was left for 1 hr to ensure complete reaction. The reaction was monitored by IR and NMR spectroscopies. Synthesis of 16-functional alcohol. 14 (0.116 g, 0.125 mmol) was mixed with thioglycerol (0.108 g, 1 mmol) and 2 wt% α,α-dimethoxy-α-phenylacetophenone in a 20mL glass scintillation vial. Samples were irradiated using a medium pressure Hg lamp (light intensity 9.25mW/cm 2) until thiol and yne were completely converted as determined by RT FTIR spectroscopy. Synthesis of 16-functional acid. 14 (0.116 g, 0.125 mmol) in 2g of a 50:50 mixture of dichloromethane/methanol was mixed with thiomalic acid (0.150 g, 1 mmol) and 2 wt% α,αdimethoxy-α-phenylacetophenone in a 20 mL glass scintillation vial. Samples were irradiated using a medium pressure Hg lamp (light intensity 9.25mW/cm 2) until thiol and yne were completely converted as determined by RT FTIR spectroscopy.
Chinese Chemical Letters, 2008
A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification.