A scheme of the stepwise reaction of diphenylchlorophosphine with <Emphasis Type="Italic">N,N</Emphasis>-dialkylformamides in the presence of NaI

On an example of DMF was proposed and experimentally verified stepwise reaction scheme of the reaction of diphenylchlorophosphine with N,N-dialkylformamides. The first stage is autocatalytic reaction of the synthesis of (diphenylphosphoryl)(N,N-dialkylamino)chloromethanes proceeding through the intermediate formation of diphenyldichloro[(N,N-dialkylamino)chloromethyl]phosphoranes. In the second stage that includes NaI, the (diphenylphosphoryl)(N,N-dialkylamino)chloromethanes are reduced by diphenyliodophosphine (or triphenylphosphine) to form the final N,N-dialkyl(diphenylphosphinomethylene)iminium iodides. One can assume that the reaction of the synthesis of N,N-dialkyl(diphenylphosphinomethylene)-iminium iodides proceeds in a similar way, starting with diphenyliodphosphine.     

Effect of the Nature of the Substituent in N‐Alkylimidazole Ligands on the Outcome of Deprotonation: Ring Opening versus the Formation of N‐Heterocyclic Carbene Complexes

Complexes [Re(CO)₃(N‐RIm)₃]OTf (N‐RIm=N‐alkylimidazole, OTf=trifluoromethanesulfonate; 1 a – d ) have been straightforwardly synthesised from [Re(OTf)(CO)₅] and the appropriate N‐alkylimidazole. The reaction of compounds 1 a – d with the strong base KN(SiMe₃)₂ led to deprotonation of a central C? H group of an imidazole ligand, thus affording very highly reactive derivatives. The latter can evolve through two different pathways, depending on the nature of the substituents of the imidazole ligands. Compound 1 a contains three N‐MeIm ligands, and its product 2 a features a C‐bound imidazol‐2‐yl ligand. When 2 a is treated with HOTf or MeOTf, rhenium N‐heterocyclic carbenes (NHCs) 3 a or 4 a are afforded as a result of the protonation or methylation, respectively, of the non‐coordinated N atom. The reaction of 2 a with [AuCl(PPh₃)] led to the heterobimetallic compound 5 , in which the N‐heterocyclic ligand is once again N‐bound to the Re atom and C‐coordinated to the gold fragment. For compounds 1 b – d , with at least one N‐arylimidazole ligand, deprotonation led to an unprecedented reactivity pattern: the carbanion generated by the deprotonation of the C2? H group of an imidazole ligand attacks a central C? H group of a neighbouring N‐RIm ligand, thus affording the product of C? C coupling and ring‐opening of the imidazole moiety that has been attacked ( 2 c , d ). The new complexes featured an amido‐type N atom that can be protonated or methylated, thus obtaining compounds 3 c , d or 4 c , d , respectively. The latter reaction forces a change in the disposition of the olefinic unit generated by the ring‐opening of the N‐RIm ligand from a cisoid to a transoid geometry. Theoretical calculations help to rationalise the experimental observation of ring‐opening (when at least one of the substituents of the imidazole ligands is an aryl group) or tautomerisation of the N‐heterocyclic ligand to afford the imidazol‐2‐yl product.     

Reaction of iodo(trimethyl)silane with <Emphasis Type="Italic">N,N</Emphasis>-dimethyl carboxylic acid amides

The reactions of iodo(trimethyl)silane with N,N-dimethylformamide and N,N-dimethylacetamide Me₂NCOR (R = H, Me) at a molar ratio of 1: 2 involved mainly cleavage of the N-C(=O) bond with formation of up to 80% of N,N-dimethyltrimethylsilylamine Me₃SiNMe₂ and the corresponding acyl iodide RCOI. In the reaction with N,N-dimethylformamide, formyl iodide HCOI was detected for the first time by gas chromatography-mass spectrometry. The contribution of Me-N bond cleavage, leading to N-methyl-N-trimethylsilyl derivative Me(Me₃Si)NCOR and methyl iodide was considerably smaller. Another by-product was the corresponding N-methyl imide MeN(COR)₂ formed by reaction of the initial amide with acyl iodide. The primary intermediate in the reaction of iodo(trimethyl)silane with DMF and DMA is quaternary ammonium salt [Me₂(Me₃Si)N⁺COR] I⁻ which decomposes via dissociation of the N-CO and N-Me bonds.     

Dechlorination of N-chloro poly(hexamethylene adipamide) and N-chloro poly(ε-caprolactam) products to the corresponding polyamides

A rapid dechlorination method of N-chloro poly(hexamethylene adipamide) and N-chloro poly(ε-caprolactam) to the corresponding polyamides was studied. This method can be used for molecular weight determinations of N-chloro polyamides by viscosimetric measurements. The dechlorination was achieved in formic acid solution by the reaction of N-chloro polyamides with trialkyl phosphites. The reaction was exothermic and vigorous and was applied to a series of products of various degrees of N-chlorination covering the range of 0–100%. No N—Cl was detected by iodimetric titration of the dechlorination products. The dechlorination of N-chloro polyamides was demonstrated by infrared (IR) spectroscopy. No significant molecular weight reduction except that taking place in the N-chlorination reaction of poly(hexamethylene adipamide) was observed.     

Kinetic and spectroscopic investigations of aqueous micelles of cationic surfactants

The aqueous micellar solutions of monocationic surfactants N-hexadecyl-N,N,N-trimethylammonium bromide (CTABr), N-hexadecyl-N,N,N-trimethylammonium nitrate (CTANO₃), N,N,N-tributyl-N-hexadecylammonium bromide (CTBABr) and gemini surfactants 1,4-bis(N-hexadecyl-N,N-dimethylammonium)ethane dibromide (C-E-C2Br), 1,4-bis(N-hexadecyl-N,N-dimethylammonium)propane dibromide (C-P-C2Br), and 1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide (C-B-C2Br) were studied with a solvatochromic probe, 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate, better known as Reichard’s ET-30 dye. The local polarity at the probe site (E_T) was calculated from the wavelength maximum of the lowest-energy intramolecular charge-transfer ϖ-ϖ* absorption band of ET-30. The results were compared with a kinetic investigation of the cyclization of 2-(3-bromopropyloxy)phenoxide (PhBr7) in micelles; this reaction is a model for S_N2 reactions and it depends on medium polarity.     

Synthesis and photochemical properties of poly(ester–amide)s containing norbornadiene (NBD) residues

N,N′‐Bis[(3‐carboxynorbornadien‐2‐yl)carbonyl]‐N,N′‐diphenylethylenediamine (BNPE) was synthesized in 70% yield by the reaction of 2,5‐norbornadiene‐2,3‐dicarboxylic acid anhydride with N,N′‐diphenylethylenediamine. Other dicarboxylic acid derivatives containing norbornadiene (NBD) residues having N,N′‐disubstituted amide groups were also prepared by the reaction of 2,5‐NBD‐2,3‐dicarboxylic acid anhydride with certain secondary diamines. When the polyaddition of BNPE with bisphenol A diglycidyl ether (BPGE) was carried out using tetrabutylammonium bromide as a catalyst in N‐methyl‐2‐pyrrolidone at 100°C for 12 h, a polymer with number average molecular weight of 69,800 was obtained in 98% yield. Polyadditions of other NBD dicarboxylic acid derivatives containing N,N′‐disubstituted amide groups with BPGE were also performed under the same conditions. The reaction proceeded very smoothly to give the corresponding NBD poly(ester–amide)s in good yields. Photochemical reactions of the obtained polymers with N,N′‐disubstituted amide groups on the NBD residue were examined, and it was found that these polymers were effectively sensitized by adding appropriate photosensitizers such as 4‐(N,N‐dimethylamino)benzophenone and 4,4′‐bis(N,N‐diethylamino)benzophenone in the film state. The stored energies in the quadricyclane groups of the polymers were also evaluated to be about 94 kJ/mol by DSC measurement of the irradiated polymer films. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 917–926, 1999     

Reaction of sulfenes with heterocyclic N,N-disubstituted α-aminomethyleneketones. XIII. Synthesis of 1,2-oxathiino[6,5-f]quinazoline derivatives

The 1,4-cycloaddition of sulfene to N,N-disubstituted (E)-6-aminomethylene-7,8-dihydro-(2-methyl)-(2-phenyl)quinazolin-5(6H)-ones I gave N,N-disubstituted 4-amino-3,4,5,6-tetrahydro-(8-methyl) (8-phenyl)-1,2-oxathiino[6,5-f]quinazoline 2,2-dioxides II , which are derivatives of the new heterocyclic system 1,2-oxathiino[6,5-f]quinazoline. With 2-phenylenaminones Id-h , the cycloaddition occurred, generally in satisfactory yields, both in the case of aliphatic N,N-disubstitution and aromatic N-monosubstitution, whereas with 2-methyl enaminones Ia-c the reaction took place in low yields only in the case of aliphatic N,N-disubstitution. Also the reaction of 2-phenyl enaminones Id-g with chlorosulfene occurred as with sulfene, giving a mixture of cycloadducts which were dehydrochlorinated in situ with DBN to afford N,N-di-substituted 4-amino-5,6-dihydro-8-phenyl-1,2-oxathiino[6,5-f]quinazoline 2,2-dioxides III generally in satisfactory yields. Compounds III could not be dehydrogenated either by DDQ in boiling benzene or by palladium on carbon in boiling p-cymene.     

One-pot tandem ring-opening polymerization of N-sulfonyl aziridines and “click” chemistry to produce well-defined star-shaped polyaziridines

An effective approach for fast synthesis of well-defined star-shaped poly(2-methyl-N-tosylaziridine)s was developed by one-pot tandem ring-opening polymerization (ROP) of N-sulfonyl aziridines with trimethylsilyl azide (TMSN₃) and “click” reaction with alkynes. Azido terminated polyaziridines (α-N₃-PAzs) could be achieved via ROP of N-sulfonyl aziridines with TMSN₃ in the presence of organic superbases. The catalytic efficiency of organobases, including 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA), was evaluated, and all of them except TBD afforded “living”/controlled ROP of 2-methyl-N-tosylaziridines (TsMAz). Star-shaped polyaziridines were then fastly synthesized by the one-pot tandem strategy. During the reaction process, PMDETA catalyzed ROP first, then was triggered to be a ligand by adding CuBr for “click” reaction. Well-defined 3- and 4-arm star P(TsMAz)s were successfully prepared, and subsequently desulfonylated to give star-shaped polypropylenimines (PPIs). PPI stars exhibited intrinsic photoluminescence properties from the polyamine arms.     

Synthesis of N-Carbobenzoxy-N,N-acetals

A series of N-carbobenzoxy-N,N-acetals have been synthesized by the reaction of aromatic aldehydes or certain aliphatic aldehydes with benzyl carbamate and morpholine. The N,N-acetals can be converted into N-carbobenzoxy-N,S-acetals with benzyl thiol.     

Towards the Synthesis of Azoacetylenes

The synthesis of azoacetylenes (=dialkynyldiazenes) 1 and 2 has been investigated. They represent a still elusive class of chromophores with potentially very interesting applications as novel bistable photochemical molecular switches or as antitumor agents (Fig. 1). Our synthetic efforts have led us alongside three different approaches (Scheme 1). In a first route, it was envisioned to generate the azo (=diazene) bond by photolysis of N,N′‐dialkynylated 1,3,4‐thiadiazolidine‐2,5‐diones that are themselves challenging targets (Scheme 2). Attempts are described to obtain the latter by alkynylation of the parent heterocycle with substituted alkynyliodonium salts. In a conceptually similar approach, the no‐less‐challenging dialkynylated 9,10‐dihydro‐9,10‐diazanoanthracene ( 29 ) was to be generated by alkynylation of the unsubstituted hydrazine 28 (Scheme 6). In a second route, the generation of the N?N bond from Br‐substituted divinylidenehydrazines (ketene‐azines) 35 was attempted in a synthetic scheme involving an aza‐Wittig reaction between azinobis(phosphorane) 36 and (triisopropylsilyl)ketene 37 (Scheme 7). Finally, a third approach, based on the formation of the central azo bond as the key step, was explored. This route involved the extrapolation of a newly discovered condensation reaction of N,N‐disilylated anilines with nitroso compounds (Scheme 11, and Tables 1 and 2) to the transformation of N,N‐disilylated ynamine 55 and nitroso‐alkyne 54 (Scheme 13).     

Synthesis of 4-Aryl-1,5-benzodiazepine-2-carboxamides

4,N-Diaryl-1,5-benzodiazepine-2-carboxamides were synthesized by acid-catalyzed reaction of (Z)-4,N-diaryl-2-hydroxy-4-oxo-2-butenamides with o-phenylenediamine or N,N'-bis(triphenylphosphoranediyl)-o-phenylenediamine. The reaction mechanism is discussed.     

New Synthesis and Properties of 3-Alkyl-, 3-Chloroalkyl-, 3-Perfluoroalkyl-, and 3-Aryl-1-methyl-(5-halo)pyrazoles from Chloro(bromo)vinyl Ketones and N,N-Dimethylhydrazine

A new regioselective heterocyclization was revealed in the reaction of 2-chloro- and 2,2-dichloro(bromo)vinyl ketones with N,N-dimethylhydrazine to afford 3-substituted 1-methyl(5-halo)pyrazoles. The reaction is accompanied by elimination of methyl halide and formation of up to 90% of N,N,N-trimethylhydrazinium halide as the second product.     

Syntheses with nitriles. 60. Preparation of 4-amino-5-cyano-6-phenylpyrimidines from 2-amino-1,1-dicyano-2-phenylethene

The reaction of 2-amino-1,1-dicyanobut-1-ene and 2-amino-1,1-dicyano-2-phenylethene, respectively, with N,N-dimethylformamide dimethylacetal provided the corresponding (N,N-dimethylaminomethylene)amino derivatives. 2-[(N,N-Dimethylaminomethylene)amino]-1,1-dicyano-2-phenylethene was converted into 4-amino-5-cyano-6-phenylpyrimidines by treatment with primary aliphatic and aromatic amines. The structure of the reaction products was confirmed by ¹³C nmr spectroscopy.     

Study of the reaction of methyltris(dimethylamino)silane with diamines

Tris(dimethylamino)methylsilane reacts with N,N′-dialkyldiamines to give the corresponding substituted 1,3,2-diazasilacycloalkanes. In contrast, the reaction with an N-alkyldiamine yields the corresponding polycyclic silazane.     

Synthesis of N-(2-Benzene-2,2-dichloroethylidene)-4-chlorobenzenesulfonamide and N-(2-Benzene-2,2- dichloroethylidene)-4-methylbenzenesulfonamide

In reaction of N,N-dichloro-4-chlorobenzene- and N,N-dichloro-4-methylbenzenesulfonamides with phenylacetylene were obtained in good yield N-(2-benzene-2,2-dichloroethylidene)arenesulfonamides. The latter undergo nucleophilic addition of water, ethanol, and arenesulfonamides.     

Synthescs and some reactions of N,N'-diamino-2,2′- and −4,4′-bipyridinium salts

The syntheses and some reaetions of N,N'-diamino-2,2′- and 4,4′-bipyridinium salts (IV, V and VI) are described. These compounds are prepared by the reaction of bipyridyls (I-III) with O-mesitylenesulfonylhydroxylamine in moderate to good yields. Compounds IV and VI were found to give the N,N'-diacyl derivatives by the reaction with acyl chlorides and to undergo 1,.3-dipolar cycloaddition reaction with an acetylenic compound to give 1:2 adducts. Photo-irradiation of N,N'-dibenzoylimino-2,2′-bipyridinium betaine (IX) isomerizes to a mono diazepine derivative (XVI).     

Cocondensation of urea with methylolphenols in acidic conditions

The reactions of urea with methylolphenols under acidic conditions were investigated using 2- and 4-hydroxybenzyl alcohol and crude 2,4,6-trimethylophenol as model compounds. The reaction products were analyzed with ¹³C-NMR spectroscopy and GPC. From the reaction of urea with 4-hydroxybenzyl alcohol, the formations of 4-hydroxybenzylurea, N,N′-bis (4-hydroxybenzyl) urea, and tris(4-hydroxybenzyl) urea were confirmed and the formations of N,N-bis(4-hydroxybenzyl) urea and tetrakis (4-hydroxybenzyl) urea were suggested. From the reaction of urea and 2-hydroxybenzyl alcohol, 2-hydroxybenzylurea and N,N′-bis(2-hydroxybenzyl) urea were identified. Further, the alternative copolymer of urea and phenol could be synthesized by the reaction of urea with 2,4,6-trimethylophenol. It was also found that the cocondensation between p-methylol group and urea prevails against the self-condensation of the methylolphenol even at the low pH below 3.0, and that p-methylol group has the stronger reactivity to urea than o-methylol group. © 1992 John Wiley & Sons, Inc.     

Rapid Synthesis of Alkoxyamine Hydrochloride Derivatives from Alkyl Bromide and N,N′-Di-tert-butoxycarbonylhydroxylamine [(Boc)2NOH]

The conventional route to alkoxyamine hydrochloride derivatives is by reaction of alkyl bromides with N-hydroxyphthalimide or N-hydroxysuccinimide followed by addition of hydrazine and HCl. Transformation of an alkyl bromide to the corresponding alkoxyamine hydrochloride can be accomplished more rapidly in good yields without using hazardous hydrazine by reaction of (Boc)₂NOH (N,N′-di-tert-butoxycarbonylhydroxylamine) and alkyl bromide followed by addition of HCl. Alkoxyamine hydrochlorides are powerful reagents in organic synthesis that can be used to synthesize alkoxyimino derivatives after condensation with a ketone or aldehyde.     

Cationic polyelectrolytes. IV. Kinetic study of the reaction of acrylic polymers containing tertiary amine groups with halogenated compounds in dipolar aprotic solvents

The reaction kinetics of halogenated compounds with tertiary amine groups attached at an acrylic macromolecular chain have ben studied. Three acrylic polymers were used. Two of them have mainly a structural unit of N, N-dimethylaminopropylacrylamide and the third is poly(N,N-dimethylaminoethylmethacrylate). Dimethylformamide, dimethylacetamide, and dimethylsulfoxide (DMSO) were used as dipolar aprotic solvents. Benzyl chloride and allyl chloride were considered as halogenated compounds with increased reactivity. The reaction kinetics depend on the polymer and halogenated-compound structures as well as the nature of the solvent. In the most of the cases the reactions carried out on polymers are accompanied by self-accelerating processes, with the exception of DMSO, which obviously has normal second-order kinetics. The reaction of polymers containing units of N,N-dimethylaminopropylacrylamide are compared with one having a low molecular weight, for instance N,N′-bis(3-dimethylaminopropyl)glutaramide.     

Enantioselective Oxidative Aerobic Dealkylation of N‐Ethyl Benzylisoquinolines by Employing the Berberine Bridge Enzyme

N‐Dealkylation methods are well described for organic chemistry and the reaction is known in nature and drug metabolism; however, to our knowledge, enantioselective N‐dealkylation has not been yet reported. In this study, exclusively the (S)‐enantiomers of racemic N‐ethyl tertiary amines (1‐benzyl‐N‐ethyl‐1,2,3,4‐tetrahydroisoquinolines) were dealkylated to give the corresponding secondary (S)‐amines in an enantioselective fashion at the expense of molecular oxygen. The reaction is catalyzed by the berberine bridge enzyme, which is known for C? C bond formation. The dealkylation was demonstrated on a 100 mg scale and gave optically pure dealkylated products (ee>99 %).