Al/N-based active Lewis pairs: isocyanate insertion products as efficient nucleophiles employed for the facile generation of highly functional molecules

AbstractThe previously reported active Lewis pair (ALP) iBu2Al–N(2-Ad)NC5H10 (1) (2-Ad = 2-adamantyl) is readily accessible by hydroalumination of the hydrazone H10C5N–N=(2-C10H14) with H–AliBu2. Treatment of 1 with two equivalents of isocyanates R-N=C=O yields six-membered AlC2N2O heterocycles 2 (2a, R = Ph; 2b, R = p-Tol) by dual insertion into the Al–N bonds. 2a reacts as a nucleophile with carboxylic acid chlorides R-C(O)–Cl [R = CH2tBu, p-Tol, H2CCH(Me)C6H4(4-CH2CHMe2) (Ibu-profen acid chloride), 0.5 (1,4-C6H4)] to afford by elimination of iBu2AlCl and hydrolysis new triuret derivatives R-C(O)[N(Ph)C(O)]2–N(2-Ad)NC5H10 (3a to 3d) as colourless, sparingly soluble solids in moderate (3c) to high (3b) yields. The analogous reaction of 2a with (p-Tol)–C(Cl)=N(p-Tol) leads to the imidoyl derivative (p-Tol)N=C(p-Tol)[N(Ph)C(O)]2–N(2-Ad)NC5H10 (4a), which showed a fast exchange of phenyl and tolyl groups to yield a mixture of isomers. The analogous reaction of 2b affords the corresponding compound 4b for which a single isomer is isolated despite the scrambling of substituents.

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Preparation and reactions of thieno[3,2-b]furan derivatives

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19861685 ◽

1986 ◽

Vol 51 (8) ◽

pp. 1685-1691 ◽

Cited By ~ 3

Author(s):

Eva Kraľovičová ◽

Alžbeta Krutošíková ◽

Jaroslav Kováč

Keyword(s):

Carboxylic Acid ◽

Carboxylic Acids ◽

Acid Chloride ◽

Thionyl Chloride ◽

Acid Chlorides ◽

Carboxylic Acid Chloride ◽

Furan Derivatives ◽

Nucleophilic Reactions ◽

Triethylbenzylammonium Chloride

Reactions of 3-(5-aryl-2-furyl)propenoic, 3-(2-benzo[b]furyl)propenoic and 3-(5-ethoxycarbonyl-4H-furo[3,2-b]-2-pyrrolyl)propenoic acids with thionyl chloride in the presence of triethylbenzylammonium chloride were investigated. The obtained 2-arylthieno[3,2-b]-furan-5-carboxylic acid chlorides Ia - Ic and 3-chlorothieno[3,2-b]benzo[b]furan-2-carboxylic acid chloride afforded in substitution nucleophilic reactions the corresponding esters V and carboxylic acids VI which were decarboxylated to VII. 3-Chlorothieno[3,2-b]benzo[b]furan-2-carboxylic acid chloride (Id), 6-ethoxycarbonyl-3-chlorothieno[2',3':4,5]furo[3,2-b]pyrrole-2-carboxylic acid chloride (IV), and ethyl 3-chlorothieno[2',3':4,5]furo[3,2-b]indole-2-carboxylate (VIII), synthesized under conditions of triethylphosphite reduction from ethyl 6-chloro-2-(2-nitrophenyl)thieno[3,2-b]furan-5-carboxylate (Va), are new heterocyclic systems.

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Eco-Friendly Synthesis of Peptides Using Fmoc-Amino Acid Chlorides as Coupling Agent Under Biphasic Condition

Protein and Peptide Letters ◽

10.2174/0929866527666201119161116 ◽

2020 ◽

Vol 27 ◽

Author(s):

Santosh Y. Khatavi ◽

K. Kantharaju

Keyword(s):

Amino Acid ◽

Acid Chloride ◽

Acid Ester ◽

Analytical Techniques ◽

Peptide Bond ◽

Amino Acid Ester ◽

Acid Chlorides ◽

Peptide Bond Formation ◽

Green Protocol ◽

Additional Base

Background: Agro-waste derived solvent media act as a greener process for the peptide bond formation using Nα - Fmoc-amino acid chloride and amino acid ester salt with in situ neutralization and coupling under biphasic condition. The Fmoc-amino acid chlorides are prepared by the reported procedure of freshly distilled SOCl2 with dry CH2Cl2. The protocol found many added advantages such as neutralization of amino acid ester salt and not required additional base for the neutralization, and directly coupling take place with Fmoc-amino acid chloride gave final product dipeptide ester in good to excellent yields. The protocol occurs with complete stereo chemical integrity of the configuration of substrates. Here, we revisited Schotten-Baumann condition, instead of using inorganic base. Objective: To develop green protocol for the synthesis of peptide bond using Fmoc-amino acid chloride with amino acid esters salt. Methods: The final product isolated is analyzed in several spectroscopic and analytical techniques such as FT-IR, 1H-, 13CNMR, Mass spectrometry and RP-HPLC to check stereo integrity and purity of the product. Conclusion: The present method developed greener using natural agro-waste (lemon fruit shell ash) derived solvent medium for the reaction and not required chemical entity.

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ChemInform Abstract: Organomanganese(II) Reagents. Part 19. Acylation of Organomanganese Chlorides by Carboxylic Acid Chlorides in THF: A Clear Improvement in the Field of the Preparation of Ketones from Organomanganese Compounds.

ChemInform ◽

10.1002/chin.199034080 ◽

1990 ◽

Vol 21 (34) ◽

Author(s):

G. CAHIEZ ◽

B. LABOUE

Keyword(s):

Carboxylic Acid ◽

Acid Chlorides ◽

Organomanganese Compounds

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Synthesis and Characterization of the Germathioacid Chloride Coordinated by an N-Heterocyclic Carbene §

Inorganics ◽

10.3390/inorganics6030076 ◽

2018 ◽

Vol 6 (3) ◽

pp. 76 ◽

Cited By ~ 1

Author(s):

Yasunobu Egawa ◽

Chihiro Fukumoto ◽

Koichiro Mikami ◽

Nobuhiro Takeda ◽

Masafumi Unno

Keyword(s):

Carboxylic Acid ◽

Density Functional ◽

Dft Calculation ◽

Acid Chlorides ◽

Carboxylic Acid Chloride ◽

Functional Theory ◽

Nitrogen Ligands ◽

Bond Property ◽

Nitrogen Bonds

Carboxylic acid chlorides are useful substrates in organic chemistry. Many germanium analogues of carboxylic acid chloride have been synthesized so far. Nevertheless, all of the reported germathioacid chlorides use bidentate nitrogen ligands and contain germanium-nitrogen bonds. Our group synthesized germathioacid chloride, Ge(S)Cl{C6H3-2,6-Tip2}(Im-i-Pr2Me2), using N-heterocyclic carbene (Im-i-Pr2Me2). As a result of density functional theory (DFT) calculation, it was found that electrons are localized on sulfur, and the germanium-sulfur bond is a single bond with a slight double bond property.

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