- Preparation method of N-Boc-1, 2-diaminoethane
-
The invention relates to a preparation method of N-Boc-1, 2-diaminoethane. The preparation method comprises 1) dissolving phenol, a catalyst and a base in a first organic solvent, and adding di-tert-butyl dicarbonate into the solution with the first solvent drop by drop for a reaction to obtain tert-butyl phenyl carbonate, and 2) dissolving 1, 2-diaminoethane in the first organic solvent, and adding tert-butyl phenyl carbonate into the solution drop by drop for a reaction to obtain a final product. The preparation method has simple separation and purification processes, has a small reaction temperature range and a high reaction yield and realizes a low raw material cost.
- -
-
Paragraph 0017
(2018/11/04)
-
- Exploiting Peptidomimetics to Synthesize Compounds That Activate Ryanodine Receptor Calcium Release Channels
-
Ryanodine receptor (RyR) Ca2+-release channels are essential for contraction in skeletal and cardiac muscle and are prime targets for modification of contraction in disorders that affect either the skeletal or heart musculature. We designed and synthesized a number of compounds with structures based on a naturally occurring peptide (A peptides) that modifies the activity of RyRs. In total, 34 compounds belonging to eight different classes were prepared. The compounds were screened for their ability to enhance Ca2+ release from isolated cardiac sarcoplasmic reticulum (SR) vesicles, with 25 displaying enhanced Ca2+ release. Competition studies with the parent peptides indicated that the synthetic compounds act at a competing site. The activity of the most effective of the compounds, BIT 180, was further explored using Ca2+ release from skeletal SR vesicles and contraction in intact skeletal muscle fibers. The compounds did not alter tension in intact fibers, indicating that (as expected) they are not membrane permeable, but importantly, that they are not toxic to the intact cells. Proof in principal that the compounds would be effective in intact muscle fibers if rendered membrane permeable was obtained with a structurally related membrane-permeable scorpion toxin (imperatoxin A), which was found to enhance contraction.
- Robinson, Ken,Easton, Christopher J.,Dulhunty, Angela F.,Casarotto, Marco G.
-
p. 1957 - 1971
(2018/09/11)
-
- Activation of Benzyl Aryl Carbonates: The Role of Cation-π Interactions
-
Benzyl aryl carbonates can react with a nucleophile to yield an activated electrophile and an aryloxide anion. Previously, we had utilized this in the synthesis of α-nitro esters from nitroalkanes. To further understand the process of activation of these carbonates by nucleophiles, we have performed kinetic studies on the hydrolysis of carbonates using nucleophiles. Rate constants for the hydrolysis were obtained under pseudo-first-order conditions with DABCO as the nucleophile. A comparison of rate constant for hydrolysis of isobutyl phenyl carbonate with benzyl phenyl carbonate shows that the presence of benzyl group results in a 16-fold acceleration of hydrolysis rate. This indicates that the transition state for activation of carbonate is stabilized by cation-π interactions. A comparison of the rate constant for various aromatic rings indicates that electron-donating substituents on the benzyl groups accelerate the rate of hydrolysis. Studies were also carried out with DMAP as nucleophile and the results are presented. Our studies show that stable carbonates can be activated using nucleophiles. Activated acyl groups generated from acid anhydrides have been used in several enantioselective reactions. Our studies show that carbonates can be stable alternatives to acid anhydrides.
- Reddy, Golipalli Ramana,Avadhani, Anusha S.,Rajaram, Sridhar
-
p. 4134 - 4141
(2016/06/09)
-
- MgBr 2 · OEt 2: A Lewis Acid Catalyst for the O - And N -Boc Protection of Phenols and Amines
-
MgBr2 · OEt2 efficiently catalyzes the O- and N-tert-butoxycarbonylation of functionalized phenols and amines. The presented procedure is operationally simple and done under solvent-free conditions. GRAPHICAL ABSTRACT.
- Schechter, Aaron,Goldrich, David,Chapman, Jessica R.,Uberheide, Beatrix M.,Lim, Daniel
-
supporting information
p. 653 - 660
(2015/10/29)
-
- General solvent-free highly selective N-tert-butyloxycarbonylation strategy using protic ionic liquid as an efficient catalyst
-
A simple, rapid and solvent-free protocol is described for the chemo-selective transformation of amines to tert-butyloxycarbonyl protected derivatives (NHBoc) using Boc2O and imidazolium trifluoroacetate protic ionic liquid (5-20 mol%). Unwanted side products such as isocyanate, urea or N,N-di-Boc were not detected. The scope of the protection strategy was successfully explored for substrate alcohols, phenols and thiol at elevated temperatures. Optically pure amino acids, amino acid esters and amino alcohols were efficiently converted to the corresponding N-Boc protected derivatives in excellent yields without racemization at the chiral center. The distinct advantages of this method are: operational simplicity, cleaner reaction, high selectivity, excellent yield, rapid reaction convergence, easy preparation and recyclability of the catalyst.
- Majumdar, Swapan,De, Jhinuk,Chakraborty, Ankita,Maiti, Dilip K.
-
p. 24544 - 24550
(2014/07/07)
-
- A new, efficient, and catalyst-free microwave-assisted approach for formation of O-tert-butoxy carbonates
-
A new simple, efficient, greener, and catalyst-free chemoselective protocol for the O-tert-butoxycarbonylation of various structurally diverse hydroxy compounds was carried out with (Boc)2O under microwave radiation. The corresponding O-tertbutoxy carbonates were obtained in good to excellent yields in a short reaction time without any side reactions.
- K'tir, Hacene,Amira, Aicha,Berredjem, Malika,Aouf, Nour-Eddine
-
supporting information
p. 851 - 853
(2014/06/23)
-
- Mixed metal MgO-ZrO2 nanoparticle-catalyzed O-tert-Boc protection of alcohols and phenols under solvent-free conditions
-
An environmentally benign method for O-tert-Boc protection of alcohols and phenols catalyzed by MgO-ZrO2 nanoparticles under solvent-free conditions is described. A variety of phenols, alcohols (aliphatic and aromatic) were converted to corresponding O-tert-Boc products in good to excellent yield (50-95%). The present protocol is expedient, simple, and efficient under solvent-free conditions. The MgO-ZrO2 Nps are easily prepared from inexpensive precursors, and are reusable, recyclable and chemoselective. Copyright 2012 John Wiley & Sons, Ltd. Copyright
- Gawande, Manoj B.,Shelke, Sharad N.,Branco, Paula S.,Rathi, Anuj,Pandey, Rajesh K.
-
experimental part
p. 395 - 400
(2012/09/25)
-
- An eco-sustainable erbium(iii)-catalyzed method for formation/cleavage of O-tert-butoxy carbonates
-
A new simple and effective method for the formation/cleavage of O-tert-butoxy carbonates of alcohols and phenols is proposed. Mesoporous silica-supported Er(iii) (ErIII-MCM-41) was used as an efficient and reusable solid catalyst in the solvent-free ultrasound-assisted synthesis of Boc-carbonate derivatives of a wide range of alcohols and phenols. The fast, selective deprotection of Boc-derivatives is achieved with a very low amount of Er(OTf)3 in ethanol under microwave irradiation. Therefore, the entire protection/de-protection process is very attractive, from the point of view of sustainability.
- Procopio, Antonio,Cravotto, Giancarlo,Oliverio, Manuela,Costanzo, Paola,Nardi, Monica,Paonessa, Rosina
-
experimental part
p. 436 - 443
(2011/04/17)
-
- Chemoselective O-tert-butoxycarbonylation of phenols using 6,7-dimethoxyisoquinoline as a novel organocatalyst
-
The chemoselective O-tert-butoxycarbonylation of phenols using low levels (5-0.1 mol %) of 6,7-dimeth-oxyisoquinoline as a reusable organocatalyst is described.
- Saito, Yukako,Yoshimura, Yuichi,Takahata, Hiroki
-
experimental part
p. 6915 - 6917
(2011/03/18)
-
- Triphenylphosphine as a novel organocatalyst for chemoselective O-tert-butoxycarbonylation of phenols
-
A novel organocatalytic procedure for the chemoselective O-tert-butoxycarbonylation of phenols under neutral and neat conditions is described. Georg Thieme Verlag Stuttgart.
- Chebolu, Rajesh,Chankeshwara, Sunay V.,Chakraborti, Asit K.
-
p. 1448 - 1454
(2008/12/21)
-
- Organocatalytic methods for chemoselective O-tert-butoxycarbonylation of phenols and their regeneration from the O-t-Boc derivatives
-
(Chemical Equation Presented) Carbon tetrabromide (CBr4) catalyzes O-tert-butoxycarbonylation of functionalized phenols without any side reactions (bromination, addition of CBr3 to a double bond, and formation of symmetrical diaryl carbonates, cyclic carbonates, or carbonic-carbonic anhydrides). The parent phenols are regenerated from the O-t-Boc derivatives by the catalyst system CBr4-PPh3 without affecting other protecting groups (aryl alkyl ether, alkyl ester, and thioacetal) or competitive side reaction such as bromination, nitrene (from NO2) and α,α-dibromoolefine (with CHO/COMe) formation, and transesterification (with CO2Me/Et) taking place.
- Chankeshwara, Sunay V.,Chebolu, Rajesh,Chakraborti, Asit K.
-
supporting information; scheme or table
p. 8615 - 8618
(2009/04/11)
-
- Chemoselective O-tert-butoxycarbonylation of hydroxy compounds using NaLaTiO4 as a heterogeneous and reusable catalyst
-
A facile, efficient and chemoselective protocol for O-tert-butoxycarbonylation of various hydroxy compounds has been developed using NaLaTiO4 (layered perovskite) as a novel catalyst. The catalyst showed remarkable activity and reusability affording high yields of the desired products under mild reaction conditions.
- Singh, Savita J.,Jayaram, Radha V.
-
p. 4249 - 4251
(2008/09/21)
-
- A novel tert-butoxycarbonylation reagent: 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI)
-
The use of 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI) as a tert-butoxycarbonylation reagent for acidic proton-containing substrates such as phenols, aromatic and aliphatic amines hydrochlorides, and aromatic carboxylic acids in the absence of a base is described. The reactions proceed chemoselectively in high yield under mild conditions.
- Saito, Yukako,Ouchi, Hidekazu,Takahata, Hiroki
-
p. 11599 - 11607
(2007/10/03)
-
- The first simple method of protection of hydroxy compounds as their O-Boc derivatives under Lewis acid catalysis
-
The first Lewis acid catalyzed protection of alcohols as Boc derivatives is described. Zinc acetate is a very efficient catalyst for this transformation and the reaction can be applied to primary, secondary and aromatic alcohols, providing the first example of a generally applicable method. Georg Thieme Verlag Stuttgart.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Dalpozzo, Renato,Locatelli, Manuela,Melchiorre, Paolo,Palazzi, Paolo,Sambri, Letizia
-
p. 2104 - 2108
(2008/02/05)
-
- Unusual and unexpected reactivity of t-butyl dicarbonate (Boc2O) with alcohols in the presence of magnesium perchlorate. A new and general route to t-butyl ethers
-
(Chemical Equation Presented) A new mild method for protecting alcohols as t-butyl ethers is reported. The reaction proceeds with Mg(ClO4) 2 and Boc2O and shows general applicability. The deprotection of t-butyl ethers has also been revisited. Preliminary results indicate the CeCl3·7H2O/Nal system is a very suitable catalyst for their removal.
- Bartoli, Giuseppe,Bosco, Marcella,Locatelli, Manuela,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
-
p. 427 - 430
(2007/10/03)
-
- Base-labile tert-butoxycarbonyl (Boc) group on phenols
-
Phenols are deprotected with weak bases from their tert-butoxycarbonyl (Boc) derivatives. Boc deprotection with bases can avoid side reactions during the deprotection with acids. We note the lability of the Boc to bases and are able to utilize it as a new cleavage condition for synthetic studies.
- Nakamura, Kozo,Nakajima, Takero,Kayahara, Hiroshi,Nomura, Eisaku,Taniguchi, Hisaji
-
p. 495 - 499
(2007/10/03)
-
- 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline: A novel and chemoselective tert-butoxycarbonylation reagent
-
(formula presented) The use of 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI) as tert-butoxycarbonylation reagent for aromatic and aliphatic amine hydrochlorides and phenols in the absence of a base has been demonstrated. The reactions proceed chemoselectively in high yield under mild conditions.
- Ouchi, Hidekazu,Saito, Yukako,Yamamoto, Yutaka,Takahata, Hiroki
-
p. 585 - 587
(2007/10/03)
-
- Phase transfer catalysis in the tert-butyloxycarbonylation of alcohols, phenols, enols, and thiols with di-tert-butyl dicarbonate
-
It is shown that the tert-butyloxycarbonylation of phenols, alcohols, enols, and thiols can be accomplished by reaction of these functionalities with di-tert-butyl bicarbonate under phase transfer conditions.The reactions proceed in high yield and can also be used for the introduction of t-BOC groups onto functionalized polymer backbones such as poly(p-hydroxystyrene).In addition, a study is made of the selectivity towards tert-butyloxycarbonilation of various polyfunctional compounds.
- Houlihan, F.,Bouchard, J.,Frechet, J. M. J.,Willson, C. G.
-
p. 153 - 162
(2007/10/02)
-
- Regioselective Arylation of 3-Bromopyridine
-
The addition of aryl Grignard reagents to the 1-phenoxycarbonyl salt of 3-bromopyridine affords 2-aryl-5-bromo-1-phenoxycarbonyl-1,2-dihydropyridines and 4-aryl-3-bromo-1-phenoxycarbonyl-1,4-dihydropyridines.The crude dihydropyridines were aromatized with o-chloranil in refluxing toluene to give 4- and 6-aryl-3-bromopyridines.The regioselectivity of this two-step process, 6- vs. 4-substitution, was examined and found to be dependent upon the structure of the Grignard reagent.Unhindered aryl Grignard reagents, e.g., phenyl and 2-naphthyl, gave mainly 6-aryl-3-bromopyridines (49-52percent) along with 9percent of the 4-substituted isomer and less than 4percent of the 2-aryl-3-bromopyridine.Hindered aryl Grignard reagents, e.g., o-tolyl and 1-naphthyl, are less regioselective.When a catalytic amount of cuprous iodide is present during the Grignard reaction, nearly exclusive 1,4-addition results.The crude 4-aryl-3-bromo-1,4-dihydropyridines were aromatized with p-chloranil to provide 4-aryl-3-bromopyridines in good yield and high isomeric purity.The sequential use of the cuprous iodide-catalyzed Grignard reaction and the "normal" Grignard reaction provided a regiospecific synthesis of 3-bromo-6-(p-methoxyphenyl)-4-phenylpyridine from 3-bromopyridine.
- Comins, Daniel L.,Mantlo, Nathan B.
-
p. 1239 - 1243
(2007/10/02)
-
- The Thermal Decompositions of Carbamates. IV. The Reactions of Isopropyl N,N-Dimethylcarbamate and t-Butyl N,N-Dimethylcarbamate
-
The thermal decompositions of isopropyl N,N-dimethylcarbamate and t-butyl N,N-dimethylcarbamate are shown to occur over the temperature range 485-602 K through the reactions which are described as first-order unimolecular processes for which the rate equations are isopropyl , t-butyl For both carbamates these rate equations describe the rates of formation of the amine and the appropriate alkene but apparently overestimate the rate of carbon dioxide formation.The discrepancy in the carbon dioxide data is explained in terms of the formation of an amine-carbon dioxide adduct during the condensation stage of the analyses.The adduct is described as an ammonium carbamate which undergoes hydrolysis in solution to free the original amine.The existence of transesterification in the gas phase is ruled out.
- Daly, Neil J.,Ziolkowski, Franciszek
-
p. 481 - 490
(2007/10/02)
-