Alkylation of cyclododecanone with α,ω-dibromoalkanes under conditions of phase-transfer catalysis

Alkylation of cyclododecanone with ,-dibromoalkanes Br(CH) _n Br (n=3, 4, 5) under conditions of phase-transfer catalysis in the presence of KOH results in the formation of either bicyclic ketones forn=3 and 5 or a mixture of bicyclic and spirocyclic ketones forn=4.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1436–1438, August, 1994.     

Synthesis of N-(ω-trimethylsilylalkyl)purines under conditions of interfacial catalysis

A Method of synthesis of N-(-trimethylsilylalkyl)purines, by alkylation of potassium salts of purine bases by 3-chloropropyltrimethylsilane and chloromethyltrimethylsilanes under conditions of interfacial catalysis, has been developed. Hydroxylation of the N-allyl group by dimethylphenylsilane, which is an alternative pathway of synthesis of silicon-containing purine derivatives, has been accomplished for the first time in the purine series. The structure of the compounds obtained was established by methods of PMR and UV spectroscopy.Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 654-658, May, 1995. Original article submitted October 25, 1994.     

Synthesis of α-amino acids using transition metal catalysis - alkylation of schiff bases derived from α-amimo acid esters (regio,stereo - selectivity)

A general approach to the synthesis of γ,δ-unsaturated α-amino acid esters is described. Schiff bases derived from glycine and alanine esters were alkylated in the presence of palladium or molybdenum catalysts under neutral or basic conditions using allylic carbonates, esters or halides, (20–95% yield). These less stabilized nucleophiles reacted with the η³ allyl species on the side opposite to the palladium and they can be classified as soft nucleophiles. The regioselectivity was studied with various unsymmetrical electrophiles. After hydrolysis, several functionalized α-amino acids of biological interest (enzymes inhibitors) were obtained. Asymmetric palladium allylic alkylation of the benzophenone imine glycine methyl ester using Pd(OAc)₂ + (+)DIOP was achieved with up to 68 % ee ; the enantioselective Pd-promoted alkylation of this new and useful prochiral nucleophile for the synthesis of α-amino acids is one of the highest ee known.     

Synthesis of aza-crown compounds by intramolecular cyclization of ω-amino acids

A method for the synthesis of aza-crown compounds by the intramolecular cyclization of -amino acids with subsequent reduction of the lactam to a macrocyclic amine was developed. 1,8-Diazacyclotetradecane and 1,8-dioxa-4,11-diazacyclotetradecane were synthesized in preparative yields. The structural assignments were made using the IR, ¹H and ¹³C NMR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–255, February, 1992.     

Iridium catalyzed alkylation of 2′-hydroxyacetophenone with alcohols under thermal or microwave conditions

2′-Hydroxyacetophenone was alkylated with a range of substituted benzyl and heteroaryl alcohols to afford the corresponding C-alkylated products in good yields under microwave irradiation. The C-alkylated products were reacted with bromoacetonitrile to afford 2-amino-3-benzyl 1,4-naphthoquinone derivatives in moderate yields.     

Synthesis of S-Alkylisothiuronium Halides by Reaction of Thiourea with ω-(4-Hydroxyaryl)alkyl Halides

A number of new S-alkylisothiuronium salts were synthesized by reaction of -[4-hydroxy(methoxy)aryl]alkyl halides with thiourea. The resulting isothiuronium salts in aqueous solution react with sodium (potassium) halides to form halogen exchange products.     

Synthesis of diverse β-(nitrooxy)-substituted amines by regioselective ring-opening of aziridines under neat conditions

An efficient and regioselective method was developed for the synthesis of β-(nitrooxy)-substituted amine derivatives by ring-opening of different aziridines with Zn(NO₃)₂·6H₂O without using additives or catalyst. A library of β-(nitrooxy)-substituted amine derivatives having a variety of substituents has been synthesized. Excellent regioselectivity, high yields, clean reaction, ease of product isolation, easily accessible reactants, and solvent-free as well as environment friendly reaction conditions are the notable advantages of the present methodology. The nitrooxy derivative was successfully transformed into hydroxy derivative by simple reduction. Gram-scale synthesis demonstrates the potential applications of the present method.     

Fluorescence spectral changes of vacuum-deposited films of ω-(1-pyrenyl)alkanoic acids induced by an excimer laser: molecular aspects of laser annealing

Vacuum-deposited films of ω-(1-pyrenyl) alkanoic acids showed fluorescence spectral changes upon irradiation with an excimer laser and a Xe lamp, although no absorption spectral change was detected. It was confirmed that this characteristic phenomenon depends on the number of methylenes in the chain and that a non-linear photochemical process (with respect to irradiation intensity) is involved.     

Synthesis ofα-substitutedα-amino acids by the alkylation of 5-oxazolinone derivatives

Methods have been developed for the alkylation of 5-oxazolinone derivatives in DMF in the presence of K₂CO₃, KOH, or diisopropylethylamine and a phase transfer catalyst as well as for the preparation of-methyl-phenylalanine,-methylalanine,-methylalanine, and the methyl ester of N-benzoyl--methylalanine. Increasing the initial concentration of the starting 5-oxazolinone in the reaction mixture leads to a sharp drop in the yield of reaction products due to side condensation reactions. The reaction of 2-phenyl-4-benzyl-5- oxazolinone with ethyl iodide gave a dimer namely, 3-(benzoylamino)-3,5-dibenzylpyrrolidine-2,4-dione.Latvian Institute of Organic Chemistry, LV-1006 Riga. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 829–833, June, 1994. Original article submitted January 21, 1994.     

The coupling of alkylboronic acids and esters with Baylis–Hillman derivatives by Lewis base/photoredox dual catalysis

Utilizing Lewis base/photoredox dual catalysis, carbon radicals generated from either alkylboronic acids or esters were coupled with Baylis–Hillman derivatives under visible light irradiation. This protocol provides a mild and operationally simple method for the synthesis of a variety of α,β-unsaturated carbonyl compounds in a broad scope of the substrates. The mechanism of Lewis base activation and reductive quenching cycle was probably involved.     

Synthesis of β-heteroaryl carbonyl compounds via direct cross-coupling of allyl alcohols with heteroaryl boronic acids under cooperative bimetallic catalysis

The eco-friendly cooperative Cu/Pd-catalyzed oxidative Heck reaction of allyl alcohols with heteroaryl boronic acids under air was described. The ready availability of starting materials and the mild reaction conditions made this protocol a safe and operationally convenient strategy for the efficient synthesis of β-heteroaryl carbonyl compounds.     

Synthesis ofN-(amidomethyl)- andN- (imidomethyl)-α-amino acid esters by reactions of α-amino acid esters with formaldehyde and amides or imides

Reactions of hydrochlorides of glycine, alanine, phenylalanine, L-isolcucinc, and L-valine esters with aromatic and heteroaromatic carboxamides afforded hydrochlorides of the correspondingN-(amidomethyl)--amino acid esters.N-(Phthalimidomethyl)--amino acid esters were obtained by reactions of -amino acid esters containing free amino groups with formaldehyde and phthalimide, The¹H NMR studies demonstrated that the chiral centers of -amino acids may be retained in the course of condensation. Reactions of the Mannish bases obtained and their hydrochlorides with acetic anhydride and tosyl chloride afforded the correspondingN-aryl andN-sulfonyl derivatives.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp, 1761–1769, July, 1996.     

Synthesis of diethers derived from furoin by phase transfer catalysis under microwave irradiation

A series of new diethers were obtained by alkylation of furoin under microwave irradiation (MWI) in phase transfer catalysis (PTC) conditions. The products of alkyl halides were synthesized in good yields (>75%) within a few minutes, and the products of dihalides were synthesized in fair yields (about 45%). The yields are dramatically improved compared to conventional heating under the same conditions, in spite of similar profiles of rising in temperature.     

Reaction of β-iminoalcohols with sulfur dioxide. Synthesis of (±)-(2-hydroxyalkylamino)phenyl(isopropyl)-methanesulfonic acids

Reactions of 2-(N-isopropylidene)amino-2-methylpropanol, 2-(N-benzylidene)-, and 2-(N-isopropylidene) aminoethanols with sulfur dioxide in aqueous ethanol medium produce (±)-(2-hydroxyalkylamino)-phenyl(isopropyl)methanesulfonic acids. Structure of (±)-(2-hydroxyethylamino)phenylmethanesulfonic acid was determined by X-ray diffraction method.     

Synthesis of ITQ-2 zeolite under static conditions and its properties

Zeolite ITQ-2 can be synthesized by swelling the layers of MCM-22 precursor. It has a single delami-nated structure of MWW with thickness of 2.5 nm. It shows disordered properties in long range and ordered in short range, which is a promising catalytic ma…     

Synthesis of α-hydroxyphosphonate cyclotriphosphazene under solvent-free conditions with a basic catalyst

An α-hydroxyphosphonate cyclotriphosphazene compound, hexa-(4-diethylphosphate-hydroxymethyl-phenoxy)-cyclotriphosphazene) (HDHPCP), was synthesized in two steps. First, the intermediate hexa-(4-aldehyde-phenoxy)-cyclotriphosphazene (HAPCP) was synthesized by the elimination reaction of hexachlorocyctriphosphazene (HCCP) with 4-hydroxybenzaldehyde. Then HDHPCP was obtained by the Pudovik reaction under solvent-free condition. In this step, the effects of the type and amount of catalyst on reaction time and yield were investigated, and it was found that triethylamine (TEA) has better activity than KF and K₂CO₃. When the molar ratio of HAPCP to TEA was 1:5, the reaction gave an excellent yield of 95.4% in 70 min. Under these conditions, the reaction was easy to work-up, time-saving, environmentally benign, and with high yield. Fourier transform infrared, Nuclear Magnetic Resonance, and elemental analyses results confirmed that HDHPCP was synthesized successfully, and the thermal gravimetric analysis measurement indicated that it presented good thermal stability and high char residual.