Di-tert-butyl Dicarbonate Research Articles

A new synthetic approach to cyclic ureas through carbonylation using di-tert-butyl dicarbonate (boc anhydride) via one pot strategy.

A new approach has been successfully employed to synthesize cyclic ureas via carbonylation, utilizing Boc anhydride and employing K2CO3 as a base along with N,N-dimethylformamide as the solvent. Remarkably high yields were achieved using K2CO3 in conjunction with (Boc)2O, enabling the streamlined preparation of benzimidazolones and 2-benzoxazolones within a single reaction vessel. Significantly, this approach obviates the necessity for using any dangerous reagents, rendering it environmentally friendly, and its key benefit lies in being a metal-free system. The method stands out for its efficiency, concise pathway, optimization from readily accessible starting materials, and ease of execution. The resulting benzimidazolones and 2-benzoxazolones were thoroughly characterized using techniques including LCMS, 1H NMR, and 13C NMR.

SYNTHESIS AND CHARACTERIZATION OF BOC-PROTECTED THIO-1,3,4-OXADIAZOL-2-YL DERIVATIVES

Objective: The objective of this work is to synthesis thio-1,3,4-oxadiazol-2-yl derivatives for industrial applications. Methods: The synthesis was done by the reaction of (S)-2-amino-2-phenylacetic acid with ethanol-derived ethyl (S)-2-amino-2-phenylacetate. The reaction of ethyl (S)-2-amino-2-phenylacetate with Boc anhydride and hydrazine produces ethyl (S)-2-((tert-butoxycarbonyl)amino)-2-phenylacetate. The intermediate 5-alkyl amino-1,3,4-oxadiazole-2-thiols have been isolated as stable compounds. Results: To study the characteristics of these compounds, they are subjected to 1HNMR, 13CNMR, and IR. These studies examine the chemical structure of synthesized compounds. The mass of the novel compounds was established with the help of the LCMS test. The structural and optical properties were examined by the powder XRD and photoluminescence spectrum respectively. Conclusion: The sharp intense peak in the powder XRD indicates the crystal nature of the sample. The values obtained from the LCMS test indicate that the compounds have good thermal stability. The absorption peak at 358 nm in the PL spectrum indicates that the sample can be used in photoelectronic devices.

Mild Copper-Catalyzed Addition of Arylboronic Esters to Di-tert-butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates

AbstractAn efficient copper-catalyzed addition of arylboronic esters to (Boc)2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition–elimination mechanism.

Method for the Preparation of N‐protected β‐Cyano L‐alanine Tertiary Butyl Esters

AbstractHere we report a simple, efficient and scalable one‐pot procedure for the synthesis of N‐protected β‐cyano L‐alanine tertiary butyl esters from N‐protected L‐asparagines. Reaction of N‐protected L‐asparagines with 2.2 equivalents of (Boc)2O and catalytic amount of N,N‐dimethylamino pyridine (DMAP) in tertiary butanol at room temperature resulted N‐protected β‐cyano L‐alanine tertiary butyl esters. We also synthesized N‐protected β‐cyano L‐alanines from the obtained crude N‐protected β‐cyano L‐alanine tertiary butyl esters without column chromatography on gram scale in good yields. Control experiments gave the corresponding nitrile acids over the tertiary butyl esters. Later, we synthesized nitrile containing dipeptides by coupling N‐Boc‐β‐cyano L‐alanine 4 a with amino acid methyl ester hydrochlorides.

Nickel-catalyzed asymmetric reductive aryl-allylation of unactivated alkenes.

Herein we report a nickel-catalyzed asymmetric reductive aryl-allylation of aryl iodide-tethered unactivated alkenes, wherein both acyclic allyl carbonates and cyclic vinyl ethylene carbonates can serve as the coupling partners. Furthermore, the direct use of allylic alcohols as the electrophilic allyl source in this reaction is also viable in the presence of BOC anhydride. Remarkably, this reaction proceeds with high linear/branched-, E/Z- and enantio-selectivity, allowing the synthesis of various chiral indanes and dihydrobenzofurans (50 examples) containing a homoallyl-substituted quaternary stereocenter with high optical purity (90–98% ee). In this reductive reaction, the use of pregenerated organometallics can be circumvented, giving this process good functionality tolerance and high step-economy.

Versatile bifunctional building block for in situ synthesis of sub-20 nm silver nanoparticle and selective copper deposition

In this work, a new bifunctional building block is presented for the development of versatile photosensitive resists, which enable in situ synthesis of sub-20 nm silver nanoparticles (AgNPs). In addition, practical adaptation to a palladium (Pd)-free electroless plating process verifies the facile fabrication of a metallic grid-based transparent conductive film. The building block is an aromatic small molecule with α,β-unsaturated acryloyl group and para-hydroxyl group protected by an acid-labile group (i.e., Di-tert-dicarbonate (referred to as Boc anhydride)). Spectroscopy analysis verifies the ease of photopolymerization as well as deprotection of Boc from the para-hydroxyl group where plays a key role in Ag+ reduction. The studies on plasmon absorption, morphology and elemental analysis confirm that the in situ synthesized AgNPs are sub-20 nm with a uniform distribution in the polymer matrix, which is important for efficient catalytic performance in electroless copper (Cu) deposition. In addition, the photosensitive resist exhibited excellent process reliability with respect to photolithographic patterning process and electroless plating under strong alkaline solutions (pH 10–12). Finally, the present work demonstrates the successful fabrication of sub-3 μm Cu metal grids on a polyethylene naphthalate (PEN) film.

CuI-NPs catalyzed mechanochemical-assisted N-Boc protection of organic amines

A simple, solvent-free, faster and mechanochemical approach for the N-tert-butoxycarbonylation of amines catalyzed by copper iodide nanoparticles as a recyclable catalyst is described. The advantages of this method are simplicity, shorter reaction time (5–15 min), a cost-effective catalyst, and excellent product isolation (82-92%). N-Boc protection of various structurally diverse aliphatic, aromatic, and heterocyclic amines have been carried out with (Boc)2O with 10 mol% catalyst under pestle mortar grinding under solvent-free conditions. The catalyst possesses distinct advantages, ease of handling as well as removal, cleaner reactions, high activity, and environmentally benign. The final product has been characterised by various spectroscopic techniques.

Dehydrosulfurization of protected thioureas to carbodiimides employing (Boc)2O and DMAP

Abstract An efficient protocol for the synthesis of Nα-protected carbodiimides has been achieved. Nα-protected ureas were treated with P2S5 to obtain the essential precursors, thioureas. Protected thioureas undergo dehydrosulfurization in the presence of di-tert-butyl dicarbonate (Boc)2O and base catalyst 4-dimethyl amino pyridine (DMAP), to yield corresponding carbodiimides. The synthesized compounds were mainly gums, a few were solids, after the simple workup, and were characterized by IR, 1H NMR, 13C NMR and HRMS.

DMAP-Catalyzed One-Pot Synthesis of Quinazoline-2,4-diones from 2-Aminobenzamides and Di-tert-butyl Dicarbonate.

The one-pot synthesis of quinazoline-2,4-diones was developed in the presence of 4-dimethylaminopyridine (DMAP) by metal-free catalysis. The commercially available (Boc)2O acted as a key precursor in the construction of the 2-position carbonyl of quinazolinediones. The p-methoxybenzyl (PMB)-activated heterocyclization could smoothly proceed at room temperature instead of the microwave condition. This strategy is compatible with a variety of substrates with different functional groups. Furthermore, this protocol was utilized to smoothly prepare Zenarestat with a total yield of 70%.

Catalytic Deoxygenative Coupling of Aromatic Esters with Organophosphorus Compounds.

We have developed a deoxygenative coupling of aromatic esters with diarylphosphine oxides/dialkyl phosphonates under palladium catalysis. In this reaction, aromatic esters can work as novel benzylation reagents to give the corresponding benzylic phosphorus compounds. The key of this reaction is the use of phenyl esters, an electron-rich diphosphine as a ligand, and sodium formate as a hydrogen source. Arylcarboxylic acids were also applicable in this reaction using (Boc)2O as an additive. Palladium/dcype worked to activate the acyl C-O bond of the ester and to support the reduction with sodium formate.

Efficient ‘One Pot’ Nitro Reduction-Protection of γ-Nitro Aliphatic Methyl Esters

A simple and efficient protocol has been developed for the direct conversion of γ-nitro aliphatic methyl esters to N-(tertbutoxycarbonyl)amine methyl esters using NH4+HCO2- and Pd/C in the presence of (Boc)2O. There was a significant decrease in the reaction time under these conditions, increased yields and the purity of the products using this ‘one pot’ procedure.
 

Synthesis of tert-butyl 4-bromo-4-formylpiperidine-1-carboxylate

The invention relates to tert-Butyl 4-bromo-4-formylpiperidine-1-carboxylate and a series of derivatives, which can be used to treat tumor viruses. This research mainly describe a synthesis route of key intermediate for synthetizing CDK9 inhibitors and Ibrutinib. The synthesis route is mainly consisit of three steps of Boc anhydride protection, oxidation and reduction. This synthesis route provides some valuable references and experimental basis for the synthesis of CDK9 inhibitors and Ibrutinib.

Semisynthesis of an Anticancer DPAGT1 Inhibitor from a Muraymycin Biosynthetic Intermediate.

We have explored a method to convert a muraymycin biosynthetic intermediate 3 to an anticancer drug lead 2 for in vivo and thorough preclinical studies. Cu(OAc)2 forms a stable complex with the amide 4 and prevents electrophilic reactions at the 2-((3-aminopropyl)amino)acetamide moiety. Under the present conditions, the desired 5″-primary amine was selectively protected with (Boc)2O to yield 6. The intermediate 6 was converted to 2 in two steps with 90% yield.

Fe(ClO4)3⋅xH2O‐Catalysed Ritter Reaction: Synthesis of N‐tert‐Butyl Amides from Nitriles and Di‐tert‐Butyl Dicarbonate

AbstractA convenient and excellent yield procedure for the synthesis of N‐tert‐butyl Amides by Ritter reaction with nitriles and (Boc)2O in the presence of Fe(ClO4)3⋅xH2O as a highly stable, effective and available catalyst is described.

A facile method for the preparation of carbodiimides from thioureas and (Boc)2O

A concise method for the preparation of carbodiimides from thioureas using di-tert-butyl dicarbonate [(Boc)2O] as the dehydrosulfurizative reagent has been developed. Using DMAP as the catalyst, a variety of symmetric and asymmetric 1,3-diaryl thioureas were converted into the corresponding carbodiimides efficiently in a short time.

N-Boc Protection of Amines Using Silica Propyl(N-methyl) Imidazolium Chloride as an Efficient and Reusable Catalyst

A simple and efficient method for the N-Boc protection of amines using (Boc)2O in the presence of a catalytic amount of silica propyl(N-methyl) imidazolium chloride ([Sipmim]Cl) is introduced. The catalyst was efficient and reusable for this process under solvent-free conditions at ambient temperature. This methodology has several advantages in comparison with currently used methods including high yields, simple workup procedure, short reaction time, and clean and mild reaction conditions.

One-pot synthesis of molecular glass photoresists based on β-cyclodextrin containing a t-butyloxy carbonyl group for i-line lithography

Positive chemically amplified molecular glass with pendant t-butyloxy carbonyl (t-BOC) groups based on β-cyclodextrin (β-CD) was prepared. The β-CD derivatives were obtained from the reaction of β-CD and di-tert-butyl dicarbonate (DBDC) in the presence of 4-dimethylaminopyridine, and the protecting ratio was controlled using various feed amounts of DBDC. Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance were employed to characterize the chemical structure, indicating that the synthesis was successful. Thermal behavior was characterized by thermogravimetric analysis; the results showed that the initial thermal decomposition temperature occurred at approximately 160 °C, which could satisfy the lithography process. Ultraviolet–visible spectrophotometer indicated that the t-BOC-protected β-CD derivatives had low absorbance at 365 nm wavelength. Additionally, X-ray diffraction analysis results showed that the β-CD derivatives had amorphous form, and exhibited excellent film-forming property. The photoresists consisting of different t-BOC protecting groups showed high sensitivity when exposed to 365 nm light and post-baked at 105 °C for 90 s, followed by developing in 2.38 wt% aqueous tetramethylammonium hydroxide solution at room temperature. An enhanced line and space positive patterns with 1 μm resolution were delineated according to digital microscope.

The synthesis, property and reduction of high-nitrogen compound 3,3′,5,5′-tetraazido-4,4′-bis(1,2,4-triazole)

High-nitrogen compound, 3,3′,5,5′-tetraazido-4,4′-bis(1,2,4-triazole) (TABT, 83.99% N), is synthesized from sodium azide and 3,3′,5,5′-tetrabromo-4,4′-bis(1,2,4-triazole) (TBBT) which is prepared by the bromination of 4,4′-bis(1,2,4-triazole) (BTz). It is fully characterized by IR, HRMS, NMR, and single crystal X-ray diffraction showing two triazole rings of TABT perpendicular to each other. DSC and TGA are employed to study TABT’s thermal stability with a decomposition temperature at 125.39°C (onset). The calculated detonation heat of TABT and the predicted detonation velocity are 6449kJ·kg−1 and 8649m·s−1, respectively. The reduction of TABT with hydrogen and Pd/C gave the stabilized 3,3′,5,5′-tetra(t-butyloxycarbamido)-4,4′-bis(1,2,4-triazole) (11) in the presence of (Boc)2O, providing an alternative path to the high energy density material (HDEM) TNBT [3,3′,5,5′-tetranitro-4,4′-bis(1,2,4-triazole)].

Synthesis and gelation capability of Fmoc and Boc mono-substituted cyclo(L-Lys-L-Lys)s

Fmoc or Boc mono-substituted cyclo(L-Lys-L-Lys)s were synthesized via the reaction of lysine cyclic dipeptide with Fmoc N-hydroxysuccinimide este(Fmoc-OSu) and di-tert-butyl dicarbonate[(Boc)2O], respectively. The resulted mono-substituted cyclo(L-Lys-L-Lys)s(2―4) by means of test tube inversion method served as organogelators enabled to form stable thermo-reversible organogels in alcoholic, substituted benzene and chlorinated solvents, with the minimum gelation concentration(MGC) in a range of 1%―4%(mass fraction). The transmission electron microscopy(TEM) and scanning electron microscopy(SEM) observations reveal that these gelators self-assembled into 3D nanofiber, nanoribbon or nanotube network structures. The rheological measurement exhibited that the storage modulus of gels is higher than the loss one, and the complex viscosity is reduced linearly with the increasing of scanning frequency. The fluorescence spectrum of compound 2 in 1,2-dichloroethane and benzene demonstrates that the emission peak of Fmoc at 320 nm has red-shifted and the intensity decreases gradually, while the intensity of the emission peak at 460 nm substantially enhances as a function of concentration, indicating the existence of π-π stacking interactions and the formation of J-type aggregates. Meanwhile, compound 4 self-assembled into nanotubes via the stacking of multiple bilayer membranes. Fmoc and Boc disubstituted cyclo(L-Lys-L-Lys)(3) holds the relatively lower MGC values, showing the stronger gelation ability in most selected organic solvents due to the presence of both Fmoc and Boc groups.

Stereoselectively synthesis and structural confirmation of dehydrodipeptides with dehydrobutyrine.

Most of polypeptides containing α,β-dehydroamino acids have important biological activity, so exploration of synthetic method has practical significance. In this paper, dipeptides were prepared from l-threonine by protecting of c-terminal allyl acetate, and condensing reaction with a series of N-Boc amino acid. Then, treatment of dipeptides obtained with DMAP, (Boc)2O and tetramethylguanidine in the acetonitrile occured β-elimination reaction to yield stereoselectively dehydrodipeptides. Structures of dehydrodipeptides were confirmed by 1H NMR, 13C NMR and MS. Analysis of 1H NMR, 2D NMR and crystal structure showed that the dehydrodipeptides were Z-configuration.Graphical abstractDehydrodipeptides were prepared from l-threonine. Their structures were confirmed by 1H NMR, 13C NMR and MSElectronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2005-z) contains supplementary material, which is available to authorized users.