MECHANISM OF THE REACTION OF SOME STABLE HEMIMERCAPTALS WITH Secondary-AMINES: EVIDENCE AGAINST THE INTERMEDIACY OF A METHYLENESULFONIUM ION

Abstract

The reaction of the arenethiols 4a-b with formaldehyde and the sec-amines 5a-c gave the aminomethyl aryl sulfides 6a-d. The reaction of the hemimercaptals 3a-b with 5a in methanol gave 6a-b in high yield. In acetonitrile reaction media, 6b was obtained by the reaction of 3b with 5a which suggested that 7b was not an intermediate in the formation of 6b in methanolic media. The absence of 7b in methanolic media suggests that the methylenesulfonium ion 8b is not an reaction intermediate. The formation of 7b was observed in the reaction of 3b with methanol when catalyzed by the Lewis acid tetrafluoroboric acid diethyl ether complex. The experimental observations are best explained by a mechanism whereby 3a-b are in rapid equilibrium with 4a-b under the basic reaction conditions. Rapid reaction of the liberated formaldehyde with 5a leads to the normal Mannich reaction pathway. Consistent with this mechanism, the reaction of a mixture of 3a-b and 12 with 5a gave both 6a-b and 13.     

ON THE REARRANGEMENT OF N-ARYL SULFIMIDES

Abstract

N-Aryl-S,S-dialkylsulfimides, 1, with R¹ = alkyl other than CH₃, have been rearranged by heating in ethanol yielding o-alkylthiomethyl-anilines, 2, as main products. Isomeric o-methylthioalkyl-anilines, 14, are formed in minor amounts only. Reactions of sulfimides, 1, with R¹ = CH₃, with certain alkylating or acylating agents yielded o-methylthiomethylated, N-alkylated or -acylated products 9. Mechanistic considerations are discussed. The rearrangement of sulfimides 1 has been assumed to occur via [2,3]-sigmatropic reactions of intermediate azasulfonium ylids 3. Attempts to resolve (+)-camphor-10-sulfonates of N-aryl sulfimides failed, but optically active N-aryl sulfimides could be obtained by reaction of anilines with optically active sulfoxides and P₄O₁₀. Optically active 2,6-disubstituted sulfimides, 1, could be rearranged in ethanolic KOH to yield optically active cyclohexadienimines 12, indicating a transfer of asymmetry from sulfur to carbon and supporting the assumption of a sigmatropic rearrangement.     

Synthesis and properties of new binuclear nickel(ii) phthalocyanines

New binuclear nickel(ii) phthalonitrile complexes, viz., Ni^II 2,2",9(10),9"(10"),17(18),17"(18"),24(25),24"(25")-tetra(phenylene-1,2-dioxy)bisphthalocyanine and Ni^II 2,2",9(10),9"(10"),17(18),17"(18"),24(25),24"(25")-tetra(4-tert-butylphenylene-1,2-dioxy)bisphthalocyanine, were synthesized. The complexes were characterized by electronic spectroscopy and MALDI—TOF mass spectrometry and studied as active components for membranes of ion-selective electrodes in solutions of dicarboxylic acids.     

THE SYNTHESIS OF DISODIUM O-n-ALKYLTHIOPHOSPHATES

Abstract

The disodium O-alkylthiophosphates were synthesized by reaction of PSCl₃ with the corresponding alcohols to the O-alkylphosphorodichloridothioates (1), which were hydrolyzed in aqueous triethylamin–sodium acetate solution.¹ The O-alkylthiophosphates (2) were isolated as barium salts and converted to the disodium salts by Na₂SO₄.

Because the barium salts of O-ethyl- and O-n-propyl-thiophosphate were soluble in water, the corresponding dichlorido compounds were hydrolyzed directly to the disodium salts in aqueous sodium hydroxide plus dioxane according to Gray and Hamer.²

Further purification was achieved by column chromatography on Sephadex LH20 using water as an eluant. Pure products, which were not contaminated by either inorganic thiophosphate or O-alkylphosphates, were thus obtained.     

ORGANOPHOSPHORUS COMPOUNDS,XXVIII. THE REACTION OF TRIPHENYLPHOSPHINE SULFIDE WITH TETRACHLOROBENZOQUINONES

Abstract

The reaction of triphenylphosphine sulfide with tetrachloro-o-benzoquinone gives a complex of the corresponding hydroquinone and triphenylphosphine oxide. Elemental sulfur is the other product. The tetrachloro-p benzoquinone does not react to any noticeable extent under similar conditions. Several mechanisms are proposed to explain the results.     

Effect of peripheral substitution on the electronic absorption and magnetic circular dichroism (MCD) spectra of metal-free azo-coupled bisphthalocyanine

A new azo-coupled bisphthalocyanine is synthesized from the corresponding quinoxaline oxime which can be obtained by the reaction of s-trans-chloroethanedial with NN conjugated metal-free phthalocyanine. The phthalocyanine is synthesized by the reaction of 4-nitro-o-phenylenediamine with 2-nitro-9,10,16,17,23,24-hexa(hexylthio)phthalocyanine. Novel compounds are characterized by elemental analysis, UV/vis, IR and ¹H NMR, and MALDI-TOF spectroscopy. The effect of the azo units on the position and intensity of the electronic absorption and magnetic circular dichroism (MCD) spectra of the bisphthalocyanine are examined for the NN conjugated metal-free phthalocyanine.     

THE REARRANGEMENT OF ARYLSELENENAMIDES

Abstract

Attempts to synthesize N-phenylbenzeneselenena mide always produced the isomeric p-aminodiphenyl selenide, probably as a result of an acid catalyzed rearrangement. The ease with which this rearrangement occurs is contrasted with the forcing conditions required for the analogous rearrangement of sulfenamides.     

THE SYNTHESIS OF O-BRIDGED LATICYCLIC POLYNORBORNADIENES

The synthesis of the parent oxabridged laticyclic diene, COC-[3]isopolynorbornadiene 5 and the bis(oxabridged) laticyclic diene, CO²C-[4]isopolynorbornadiene 7 have each been achieved in two steps from known starting materials; the hexachloro-derivatives of 5 and 7 are also reported.     

THE EPR SPECTRUM OF COPPER-DOPED SINGLE CRYSTALS OF GLYCYLGLYCINE

Abstract

The EPR Spectrum of Cu(II)-doped into a single crystal of α-glycylglycine is reported. The results show that there are several magnetically non-equivalent sites, only two of which were strong enough to be analysed. The values parameters in the spin Hamiltonian deduced from the data are: g _z =2.242 ± 0.003, g _x =2.062 ± 0.005, g _y =2.044 ± 0.005, A _z =162.8 ± G, A _x =32.6 ± 2.0 G, A _y =21.6 ± 2.0 G. The Cu(II) environment seems to be square planar and involving four ligand molecules, each molecule forming one bond with the copper. The nitrogens are located in the trans position. The bonding is chiefly in-plane [sgrave]-bonding.     

SYNTHESIS OF PSEUDO-DISACCHARIDE ANALOGUES OF LIPID A: HAPTENS FOR THE GENERATION OF ANTIBODIES WITH GLYCOSIDASE ACTIVITY TOWARDS LIPID A

In order to develop a generic treatment of sepsis caused by infections with Gram-negative bacteria, a series of pseudo-disaccharide analogues of lipid A (1–5) was synthesized. These adducts not only harbor a 2-acylaminodideoxynojirimycin unit mimicking the transition state of the glycosidic hydrolysis, but also a 2-N, 3-O-diacylated glucosamine moiety capable of generating catalytic antibodies with more selective glycosidase properties towards lipid A.     

INFLUENCE OF WOOD EXTRACTS ON THE UV CURING OF ACRYLATE COATINGS

ABSTRACT

The effect of wood extracts on the kinetics of UV curing of an urethane diacrylate was studied by real-time FTIR spectroscopy. Whereas extracts from rose wood (Dalbergia latifolia) inhibit the reaction, curing is not significantly affected by extracts from teak wood (Tectona grandis). Data of the pendulum hardness of the coatings confirm these results. Moreover, the radical scavenging capacity of the extracts was determined relative to benzoquinone by a radiation-chemical method.     

THE SYNTHESIS OF FLUOROHETEROCYCLIC KETENE AMINALS

The synthesis of fluoroheterocyclic ketene aminals was investigated. Fluorobenzyl ketene dithioacetals 1c reacted with nitric acid in the presence of concentrated sulfuric acid to give compound 2c. 1 reacted with diamines to afford 3–4. C-fluorobenzylation of 3–4 give the corresponding 5–8.     

SYNTHESIS OF BRANCHED-CHAIN HEXULOSE DERIVATIVES AS MODEL FOR THE SYNTHESIS OF TALAROMYCINS

The synthesis of 3,5-dideoxy-1,2-O-isopropylidene-5-C-hydroxymethyl-β-D-erythro- (1) and α-L-threo-hexulopyranose (2) from 3-deoxy-1,2-O-isopropylidene-β-D-erythro-hexulopyranose (5) from D-fructose is described, as well as their respective transformation into 3,5-dideoxy-1,2-O-isopropylidene-5-C-hydroxymethyl-β-D-threo-(3) and -α-L-erythro-hexulopyranose (4) by inversion of configuration at C-4.     

THE BEHAVIOR OF N-PHENYLIMINOPHOSPHORANE TOWARDS o- AND p-QUINONES. NEW SYNTHESIS OF DIOXAZOLE AND OXADIAZOLE DERIVATIVES

ABSTRACT

N-Phenyliminophosphorane (1) reacts with 9,10-phenanthrenequinone (2a) to give the new products 2-phenylphenanthro[9,10-d][1,3,2]dioxazole (4a) and (10Z)-10-(phenylimino)-9(10H) phenanthrenone (4b). The reaction of 1 with 1,2-naphthoquinone (2b) afforded both the dioxazole derivative 5a and the known 2-anilino-naphthoquinone-1,4-anil (5b). On the other hand, 2,6-di-tert-butyl-2,3-diphenyl-2,3-dihydro-1,2,3-benzoxadiazole (6) was obtained from the reaction of (2c) with phosphinimine (1). Application of reagent 1 on 2d and 2e renders (6E)-2,3,4,5-tetrahalogeno-6-(phenylimino)-2,4-cyclohexadien-1-one 7a and 7b, respectively. Moreover, p-quinones (3a–3c) react with phosphinimine (1) to yield products 8, 9 and 10, respectively. Mechanisms accounting for the formation of the new products are discussed and the probable structures of the products are presented based on analytical and spectroscopic data.     

THE INTERACTIONS BETWEEN PERIPHERAL AND CENTRAL UNITS IN SUPRAMOLECULAR AND METALLOSUPRAMOLECULAR STRUCTURES: THE CHARACTERIZATION OF SOME MONO-, DI- AND TRINUCLEAR COMPLEXES OF A VICINAL OXIME-IMINE LIGAND

Abstract

The 1:1 molar ratio reaction of p-phenylenediamine with isonitrosoacetylacetone in chloroform led to the formation of the half unit ligand (HL); (1). Two types of the trans octahedral (L)₂Ni 2H₂O complex were characterized; the green molecular complex (2) and the associated supramolecular dark brown complex (3). Molecular association in (3) took place via inter-molecular hydrogen bonding between the amino group of a molecule and the oxygen sites of an adjacent molecule. The 1:1 molar ratio reactions of (2) with the metal acetates M(OAc)₂ (M = divalent nickel, copper or cobalt) produced the self-assembly structure (4) whereby the metal acetate is coordinated to the amino groups of the nickel(II) complex. Reaction of the dinuclear (4) with another metal acetate (1:1 molar ratio) gave the trinuclear terminated structure (5). Similar reactions of (3) with nickel acetate (1:1 or 1:2) led to formation of complexes with metallosupramolecular structures. An antiferromagnetic interaction between the peripheral and central paramagnetic units was observed from those complexes with copper(II) at the peripheral location. In all these cases the metal ions are bridged via the aromatic Schiff-base moiety. The suggested structures of the mono-, di- and trinuclear coordination compounds are in accordance with the analytical, spectral and magnetic moment data.     

CONVENIENT SYNTHETIC METHODS FOR THE PREPARATION OF N-FLUOROALKYLHYDROXAMIC ACIDS

ABSTRACT

Polyhydroxamate chelators containing fluoro substituents are of interest as potential extractants for actinides in separations involving supercritical carbon dioxide. In this context, we have developed three new reagents 1, 2, and 3, that allow the efficient incorporation of an N-fluoroalkyl hydroxamate moiety onto a variety of substrates using acylation, alkylation, and Michael addition strategies.     

ENANTIOPURE TRIOXADECALIN DERIVED LIQUID CRYSTALS: INFLUENCE OF PHENYL SUBSTITUTION ON THE MESOGENIC PROPERTIES

Nickel(0)-catalyzed reaction of pseudo-glucal 1 with Grignard reagents derived from bromobenzene and 1-bromo-4-phenylbenzene gives the corresponding β-C-aryl glycosides 2. Desilylation and hydrogenation of 2 leads to saturated β-C-aryl glycosides 4, which can be used as chiral intermediates in the synthesis of chiral liquid crystals. The combination with p-alkoxy-substituted benzaldehyde leads to compounds 5–6. Alternatively, reaction with p-alkoxy-substituted phenylboronic acids gives the bora analogues 7–9. The mesogenic properties of these compounds are strongly influenced by the presence of an additional phenyl ring in the molecule.     

THE CHEMISTRY OF SOME UREIDOBENZENESULFONYL CHLORIDES

Abstract

o-Methoxyphenyl-, N-phenyl-N′,N′-dimethyl, and N-3-acetylphenyl-urea with chlorosulfonic acid gave 4-methoxy-3-ureido, 4-(N′,N′-dimethylureido)-, and N-3-acetylureido-benzenesulfonyl chlorides respectively.

However, attempts to chlorosulfonate phenylthiourea were unsuccessful; the product was the zwitterionic sulfonic acid which did not give the sulfonyl chloride with phosphorus pentachloride.

N-Phenyl-N′-p-tolyl urea by reaction with chlorosulfonic acid afforded the corresponding 4-sulfonyl chloride. N-Phenyl-N′-2-pyridyl- and N-phenyl-N′-2-thiazolyl thioureas reacted similarly. In contrast, N-phenyl-N′-2′-pyridylurea only gave the bis-sulfonyl chloride.

Selected ureido-sulfonyl chlorides have been condensed with hydrazine and sodium azide and some reactions of the sulfonyl azides examined.

Acetylation of phenylurea gave only the N-(3-acetyl)- or the S-acetyl derivative depending on the conditions. Contrary to previous work, it is not considered that the N-(l-acetyl) phenylthiourea is formed.     

THE SYNTHESIS OF GLYCOSIDES OF 1-ETHOXYMETHYL-5-FLUOROURACIL

ABSTRACT

Three N-glycosides 3(A–C) of 1-ethoxymethyl-5-fluorouracil were synthesized by the reaction of 2 with α-bromoacetylglucose 1(A–C) under phase transfer catalysis. The compounds 3(A–C) were treated by ammonia to obtain three new compounds 4(A′–C′). Their structures were confirmed by elementary analysis, IR, ¹H NMR.     

THE SYNTHESIS OF SOME C-4 AND C-9 SUBSTITUTED DERIVATIVES OF KDN2EN METHYL ESTER

The synthesis of a number of C-4 and C-9 substituted derivatives of KDN2en methyl ester 2 is reported. 9-Deoxy-9-iodo, 9-azido-9-deoxy and 9-O-methyl derivatives of 2(compounds 5, 7and 9) were prepared from the corresponding 9-O-tosylate, methyl 2,6-anhydro-3-deoxy-9-O-p-toluenesulfonyl-D-glycero-D-galacto-non-2-enonate (3). These compounds have been fully characterised as the peracetates 6, 8 and 10. Treatment of 3 with KSAc gave the 9-thioacetyl derivative which was isolated as the peracetate 11. 4-C-Ethenyl-4-deoxy (14), 4-C-phenyl-4-deoxy (15) and 4-C-[1-(methoxycarbonyl)ethenyl]-4-deoxy (16) derivatives of 2were prepared via the palladium-catalysed coupling of the 4-epi-chloride, methyl 5,7,8,9-tetra-O-acetyl-2,6-anhydro-4-chloro-3,4-dideoxy-D-glycero-D-talo-non-2-enonate (12) with the appropriate organostannanes.