Reaction of acetyl- and alkylideneglycosylamines with diphenylphosphinous acid

An original method of synthesis of optically active α-aminophosphoryl compounds containing a carbohydrate residue is proposed.     

Impossibility of macrocyclization of resorcinol with the phenylphosphonous acid tetraethyldiamide

On the basis of resorcinol and phenylphosphonous acid tetraethyldiamide a series of new phosphorylated compounds was prepared for the first time. It was found that on the basis of these products the target macrocycle does not form either under mild or under rigid conditions because instead of macrocyclization oligomerization takes place.     

Reaction of tetracyclone with the ethyl ester of phenylphosphonous acid

Conclusions Ethyl phenylphosphonite in the presence of triethylamine is added at the carbonyl group of tetracyclone with the formation of -hydroxyphosphinate, which upon heating is converted to products which are identical to the products of 1,6- and 1,4-addition to a conjugated system of tetracyclone; in the presence of a base only the 1,6-addition occurs.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No, 6, pp. 1345–1348, June, 1979.     

Chemical reactions and reactivity of primary,secondary, and tertiary diamines with acid functionalized polymers

Reactive melt processing of different types of diamines with polyethylene containing carboxylic acid groups and polystyrene containing anhydride groups was carried out. The reactivity of primary, secondary, and tertiary diamines with these acid polymers was determined using various techniques. Molecular weight increases due to crosslinking were observed through (1) changes in the torque during the reactive processing, (2) decrease in melt flow indices, and (3) decrease in solubility of the reaction products. The chemical compositions of the reaction products were examined by Fourier transform infrared (FTIR) spectroscopy. Thermal analysis using differential scanning calorimetry (DSC) was carried out to determine the crystallization behavior, glass transition temperatures, and thermal stabilities of the reaction products. Results show that the primary amine is the most reactive towards carboxylic acid or anhydride groups followed by the secondary and then the tertiary amine. Anhydride groups on polymers are of higher activity towards secondary or primary amino groups than carboxylic acid groups in the nucleophilic acyl substitution reactions. Reaction products crosslinked with the primary diamine are less stable than their parent acidic polymers. On the other hand, crosslinking with the secondary or tertiary diamine gives products with higher thermal stability than the parent acidic polymers. The formation of reversible and irreversible crosslinks with different types of diamines is also reported. © 1992 John Wiley & Sons, Inc.     

Silicon in benzamide directed ortho metalation. Formation and reactions of benzamide benzynes

2-Trimethylsilyl-3-triflyl benzamide 3, undergoes fluoride-mediated 1,2-elimination to give the benzyne intermediate 4 which is trapped by cycloaddition (5), and nucleophilic reactions (6).     

The extraordinary reactions of phenyldimethylsilyllithium with N,N-disubstituted amides

Phenyldimethylsilyllithium reacts with N,N-dimethylamides in a variety of ways, depending upon the stoichiometry, the temperature and, most subtly, on the structure of the amide, with quite small-seeming changes in structure leading to profound changes in the nature of the products. When equimolar amounts of the silyllithium reagent and N,N-dimethylamides 6 are combined in THF at -78 degrees C, and the mixture quenched at -78 degrees C, the product is the corresponding acylsilane . If the same mixture is warmed to -20 degrees C before quenching, the product is a cis enediamine 11. The enediamines are easily isomerised from cis to trans, easily oxidised to dienediamines , and, with more difficulty, hydrolysed to alpha-aminoketones 13. If two equivalents of the silyllithium reagent are used, the product is an alpha-silylamine 20. The mechanism of formation of the enediamines appears to be by way of a Brook rearrangement of the tetrahedral intermediate 17 followed by loss of a silanoxide ion to give a carbene or carbene-like species. The 'carbene' combines with the Brook-rearranging nucleophile to give an intermediate 28, which loses another silanoxide ion to give the enediamine. The same carbene can be attacked by a second equivalent of the silyllithium reagent to give the alpha-silylamine 20. Other nucleophiles, like alkyllithiums, phenyllithium, and tributylstannyllithium also trap the carbene to give products 48-52. The intermediate anions in these reactions, when benzylic, can be further trapped with alkylating agents to give the products 33, 34 and 53-55. In special cases, the anion formed by attack on the carbene can be trapped by intramolecular reactions displacing internal leaving groups, as in the formation of the enamine 37 and the cyclopentane 41, or attacking a carbonyl group, as in the formation of the indanone 61, or attacking a double or triple bond, as in the formation of the cyclopentanes 71 and 75. In another special case, the carbene reacts with vinyllithium to give an allyllithium intermediate 56, which selectively attacks another molecule of carbene to give eventually the gamma-aminoketone 58. Small changes in the structure of the amide lead to a variety of other pathways each of which is discussed in the text. Notably, each member of the homologous series of amides Ph(CH2)nCONMe2 gives rise to a substantially different product: when n= 0, the reaction is normal, and the yield of the alph]-silylamine 20e is high; when n=1, proton transfer in the intermediate anion 64 and displacement of the phenyl group leads to the silaindane 66; when n=2, fragmentation of the intermediate anion 80, and capture of the carbene by benzyllithium leads to the 1,4-diphenylbut-2-ylamine 83; and when n=3, proton transfer in the intermediate anion 67 and displacement of the phenyl group leads to the silacyclopentane 69.     

Michael reactions of titanium enolates of glycolic acid derivatives with the Weinreb and morpholine amides of acrylic acid

The conjugate additions of titanium enolates of glycolate-derived chiral oxazolidin-2-ones to various Michael acceptors have been evaluated as an entry to enantiopure 1,2,5-trioxygenated and related synthons. alpha,beta-unsaturated Weinreb and morpholine amides do react under suitable conditions and their adducts can be converted to diverse C1-C5 chiral fragments.     

Kinetics of exchange reactions between substituted benzoic acid amides and aliphatic nitriles

The functional group exchange between benzamides and various nitriles in trifluoroacetic acid solution has been studied to obtain kinetic and thermodynamic reaction parameters. The reactions are suggested to follow a synchronous mechanism.

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Direct-type catalytic Mannich reactions of amides with imines

Direct-type catalytic Mannich reactions of amides with imines proceeded smoothly using barium phenoxide as a catalyst to afford the desired adducts in high yields with high anti selectivities.     

Acetals of lactams and acid amides. 46. Unusual reactions of α-cyano-β-dimethylaminocrotonamide with anthranilic acid derivatives

It has been shown that the reaction of the enaminoamide -cyano--dimethylaminocrotonamide with anthranilic acid and its ethyl ester unexpectedly gives quinazoline-2,4-dione and 2-methyl-3-cyano-4-quinolone, respectively. The structures of the products were confirmed by their spectra and by direct synthesis.For communication 45, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 84–87, January, 1986.     

Protein structural effects in gas phase ion/molecule reactions with diethylamine.

The relationship between gas-phase protein structure and ion/molecule reactivity is explored in comparisons between native and disulfide-reduced aprotinin, lysozyme, and albumin. Reactions are performed in the atmospheric-pressure inlet to a quadrupole mass spectrometer employing a novel capillary interface-reactor. In reactions with equal concentrations of diethylamine, multiply protonated molecules generated by electrospray ionization (ESI) of 'native' proteins shifted to lower charge states than did multiply protonated molecules from ESI of the disulfide-reduced counterparts, suggesting that the disulfide-reduced protein ions are less reactive than native protein ions of the same charge state. Differences in reactivity may arise from protonation of different amino acid residues and/or differences in the proximities of charge sites in the two molecules. These results suggest that the reactivity of multiply charged proteins can be significantly affected by their gas-phase structure.     

Redox chemistry, acid reactivity, and hydrogenation reactions of two-electron mixed valence diiridium and dirhodium complexes

The syntheses and reaction chemistry of two electron mixed-valence diphosphazane-bridged dirhodium and diiridium complexes M(2)(0,II)(tfepma)(2)(CN(t)Bu)(2)Cl(2) [M = Rh (1), Ir (2); tfepma = MeN[P(OCH(2)CF(3))(2)](2), CN(t)Bu = tert-butyl isocyanide] are described. 1 and 2 undergo addition and two-electron oxidation and reduction chemistries. In the presence of CN(t)Bu, the addition product with the stoichiometry M(2)(0,II)(tfepma)(2)(CN(t)Bu)(3)Cl(2) [M = Rh (3), Ir (3)] is generated; in the presence of 1 equiv of CN(t)Bu and 2 equiv of bis(pentamethyl-cyclopentadienyl)cobalt(II), 1 and 2 are reduced to furnish M(2)(0,0)(tfepma)(2)(CN(t)Bu)(3) [M = Rh (5), Ir (6)], which feature both four- and five-coordinate M(0) centers. Complexes 1, 2, 5, and 6 all possess coordinatively unsaturated square planar M(0) centers that are reactive: (1) 2 reacts with PhICl(2) to produce Ir(2)(II,II)(tfepma)(2)(CN(t)Bu)(2)Cl(4) (7); (2) protonation of 2 with HX yields Ir(2)(II,II)(tfepma)(2)(CN(t)Bu)(2)Cl(2)HX [X = Cl(-) (8), OTs(-) (9)]; (3) protonation of 5 with HOTs produces [Rh(2)(I,I)(tfepma)(2)(CN(t)Bu)(3)(μ-H)](OTs); and (4) the reversible hydrogenation of 2 proceeds smoothly, furnishing the cis-dihydride complex Ir(2)(II,II)(tfepma)(2)(CN(t)Bu)(2)(H)(2)Cl(2) (11). Substitution of tfepma in 2 with bis(diphenylphsophino)methane (dppm) yields the orthometalated complex Ir(2)(II,II)(dppm)(PPh(o-C(6)H(4))CH(2)PPh(2))(CN(t)Bu)(2)Cl(2)H (12). The X-ray crystal structures of 11 compounds are presented and discussed, and spectroscopic characterization by multinuclear and variable temperature NMR provides details about solution structures and in some cases the formation of isomeric products. The electronic spectra of the new complexes are also described briefly, with absorption and emission features derived from the bimetallic core.     

Highly anti-selective catalytic aldol reactions of amides with aldehydes

Barium phenoxide-catalyzed, highly anti-selective direct-type aldol reactions of amides with aldehydes have been developed. In the presence of a slight excess amount of an amide, the desired reactions proceeded smoothly under mild conditions, and a wide range of aromatic, heterocyclic, alpha,beta-unsaturated aldehydes were applicable to afford the desired adducts in high yields with high anti-selectivities. A catalytic, enantioselective reaction of an amide with an aldehyde using a chiral ligand is also described.     

Insertion reactions of beta-diketiminate-stabilised calcium amides with 1,3-dialkylcarbodiimides

A series of heteroleptic beta-diketiminate-stabilised calcium amides of the form [{ArNC(Me)CHC(Me)NAr}Ca{NR(1)R(2)}(THF)] (Ar = 2,6-diisopropylphenyl; R(1) = H, R(2) = Ar; R(1) = H, R(2) = CH(2)CH(2)OMe; R(1) = R(2) = Ph) react with 1,3-dialkylcarbodiimides, R(3)N[double bond, length as m-dash]C[double bond, length as m-dash]NR(3) (R(3) = Cy, (i)Pr), to yield the corresponding insertion products [{ArNC(Me)CHC(Me)NAr}Ca{(R(3)N)(2)CNR(1)R(2)}(THF)] at room temperature in hydrocarbon solutions. These latter compounds contain both beta-diketiminate and guanidinate ligands bound to calcium. Solid-state data are consistent with the guanidinate ligands adopting a number of binding modes including kappa(2) through kappa(3) coordination, with varying degrees of delocalisation of the non-bound guanidinate nitrogen lone-pair across the pi-framework of the ligand. DFT computational studies have been conducted to address these variations in coordination behaviour.