A simple method to determine the anomeric configuration of sialic acid and its derivatives by 13C-NMR

The anomeric configuration of sialic acid and its derivatives could be determined on the basis of the coupling pattern of C-1 in the gated proton-decoupled or selective proton decoupled ¹³C-NMR spectra; the α anomer gave a doublet C-1 signal while the β gave a singlet.The α-anomers gave a doublet C-1 signal while the β gave a singlet in their selective proton-decoupled spectra.     

1,4,4a,10b-Tetrahydro-N,N-dimethyl-4-phenanthridinamines and 1,4,4a,5,6,10b-hexahydro-N,N-dimethyl-4-phenanthridinamines

Synthetic procedures to prepare the title compounds are described. Diels-Alder cycloaddition of β-nitrostyrene derivatives 5 to N,N-dimethyl-1,3-butadien-1-amine, 6 , gave 5-aryl-N,N-dimethyl-6-nitro-2-cyclohexen-1-amines 7. Reduction of 7 with zinc in acetic acid gave the diamino derivatives 8 . Schotten-Baumann acylation of 8 gave amides 9 . Treatment of 8 with alkyl isocyanates gave the aminourea derivatives 10 . Bischler-Napieralski cyclodehydration procudure of 9 and 10 gave 1,4,4a,10b-tetrahydrophenanthridinamines 3 and N⁶-alkyl-1,4,4a,10b-tetrahydro-N⁴,N⁴-dimethyl-4,6-phenanthridinediamines 11 , respectively. Condensation of diamines 8 with aryl aldehydes under azeotropic conditions gave imines 12 which on treatment with acids yielded 6-aryl-1,4,4a,5,6,10b-hexahydro-N,N-dimethyl-4-phenanthridinamines 4 . The stereochemistry of these materials is assigned from the proton magnetic resonance studies.     

PCC-mediated novel oxidation reactions of homobenzylic and homoallylic alcohols

A new PCC-mediated carboncarbon bond cleavage reaction during oxidation of homobenzylic alcohols leading to the formation of benzylic carbonyl compounds has been observed. Homobenzylic alcohols with no benzylic substitution (R¹=H) gave benzylic aldehydes without further oxidation, while those with benzylic substitution (R¹=Me, Et, Ar) gave benzylic ketones. In contrast, homoallylic alcohols gave products arising from double bond migration, cis- to trans-olefin isomerization and/or allylic oxidation.     

Reactions of Sterically Protected 1-Halo- and 1-Pseudohalo-2-Phosphaethenyl-Lithiums

Abstract

Phosphorus analogs of alkylidenecarbenoid, Ar-P=C(X)Li, where X equals halogen or pseudohalogen atom, such as C1, Br, or SPh, have been generated by use of the 2,4,6-tri-t-butylphenyl group (abbreviated to Ar in the Scheme) as a protecting group for low coordinated organophosphorus compounds. The reaction with methyl iodide and with some aldehydes or ketones, at low temperature, gave the corresponding alkylation products^[l]. The reaction with copper salts gave 1,4-diphosphabutadiene (1) or 1,4-diphosphabutatriene (2), depending upon the substituent X^[2,3], as well as reaction conditions, such as reaction tenlperature and time, solvent, presence or absence of oxygen. Upon warming the phosphaethenyllithiun1s, thus generated, the chloro derivative of E-configuration gave a phosphaalkyne (3) via [1,2]-aromatic migration^[4], whereas the bromo derivative of Z-configuration gave a l-phospha-3,4-dihydronaphthalene derivative (4), that is a formal C-H insertion product of a phosphinidenecarbene intermediate^[5].     

Photochemical and thermal transformations of azomethine imines

The thermal and photochemical fragmentations of a few bisazoalkenes have been investigated. 2-Phenyl-4,5-disubstituted-1, 2,3-triazoles were obtained both in the thermolysis and photolysis of 1, 2-bisphenylazo-(4, 4′-dichloro) stilbene, 1, 2-bisphenylazo(4, 4′-dimethoxy)stilbene, 1, 2-bisphenylazocyclohexene and o-(phenylazo) phenyldiazocyanide. Both 2, 3-bisphenylazo-2-butene and 1, 2-bisphenylazoethylene failed to undergo either photolysis or thermolysis in the expected manner. However, 2, 3-bisphenylazo-2-butene underwent an acid-catalysed valence isomerisation to anhydro 1-phenylimino-2-phenyl-4, 5-dimethyl-1, 2, 3-trizolium hydroxide, which on photolysis gave 2-phenyl-4, 5-dimethyl-1, 2, 3-triazole. The same iminotriazolium intermediate gave a cycloadduct, 2, 6-diphenyl-3, 3a-dimethyl-4, 5-dicarbomethoxypyrazolino [2.3.c][1.2.3] triazole, on treatment with dimethyl acetylenedicarboxylate, whereas treatment with carbon disulphide gave 2-phenyl-4, 5-dimethyl-1, 2, 3-triazole. Both photolysis and thermolysis of C-biphenylene-N^α(4-chlorophenyl)-N^β-cyanoazomethine imine gave 9-fluorenone-N- (4-chlorophenyl) anil. Photolysis of 1, 2-bisphenylazoacenaphthylene in methanol gave acenaphthenequinone monophenylhydrazone.     

A biomimetic synthesis of Δ1-tetrahydrocannabinol

Condensation of 1,3-bis(trimethylsiloxy)-1-methoxybutadiene with the acid chloride 12 gave methyl olivetolate ($\text{13}$). Condensation of $\text{13}$ with (+)-p-mentha-2,8-dien-1-ol gave methyl Δ¹-tetrahydrocannabinolate ($\text{14}$) in 55% isolated yield. Alkaline hydrolysis of $\text{14}$ gave Δ-tetrahydrocannabinol ($\text{1}$, Δ¹-THC). The synthesis is patterned after the biogenesis of $\text{1}$.     

A Facile Ester Homologation of Carbonyl Compounds Via Ketene-O,S-Acetals

A usefull extension of the available methods for the conversion of carbonyl compounds into ketene-O,S-acetals^1,2,3 has been found in the Peterson olefination with methoxyphenylthiotrimethylsilyl-methyllithium 1 of aldehydes and ketones. The starting material for this reagent 1 was prepared by reaction of methoxyphenylthio-methyllithium^4,5 with chlorotrimethylsilane at -80°C in THF. Deprotonation of the obtained methoxyphenylthiotrimethylsilyl-methane with n-butyllithium at -80°C in THF gave 1 and subsequent addition of the carbonyl compound at -80°C gave mixtures of Z and E ketene-O,S-acetals 2.     

Chemical reactivity of alkylguanines. I. Methylation of O6-methylguanine derivatives

Reaction of O⁶-methylguanine (1) with CH₃I gave O⁶,3-dimethylguanine, 3,7-dimethylguanine and 3-methylguanine. In the presence of K₂CO₃, O⁶,9-dimethylguanineand imidazole ring-opened products of O⁶,7,9-trimethylguanine were produced. Methylations of O⁶,9-dimethylguanine and O⁶-methyguanosine with CH₃I gave the corresponding 7-methylated derivatives. Reaction of 1 with (CH₃)₄N⁺OH⁻ gave 1,7-, 1,9-, 3,7- and O⁶,9-dimethylguanines.     

Liquid fluidized bed starter culture ofTrichoderma reesei for cellulase production

A starter culture ofTrichoderma reesei (Rut-C30) prepared in a liquid fluidized bed reactor (LFBR) gave better growth and greater cellulase production in submerged fermentation than a conventional shake flask inoculum. The LFBR starter was prepared by first coatingT. reesei spores to 0.25 mm size corncob (1.0x10⁸g^-1) in a medium containing 1.0% corncob, 0.5 gL^-1 xylose and 0.1 gL^-1 lactose in a balanced salt solution, then fluidizing the particles in the LFBR for 36 h to allow germination of the spores, and covering the particles with an approx 30 μm thick biofilm. This biofilm that developed in constant adherence to the lignocellulosic carrier, apparently became well adapted to grow rapidly on insoluble cellulose substrates (Solca Floc), and had the enzymes of the cellulase complex induced for increased cellulase production. The LFBR starter used in a stirred tank reactor (STR) gave 15 gL^-1 biomass production and 6.5 IU mL^-1 overall cellulase activity with a volumetric productivity of 64 IU L^-1h^-1 in a 5 d fermentation, compared with a 7 d shake flask inoculum that gave 11 gL^-1 biomass and 3.2 IU mL^-1 cellulase activity, with a volumetric productivity of 31IU L^-1h^-1. The LFBR starter culture retained its viability in dry storage for 6–9 mo.     

Formation of Urazole Ring from Monoalkylhydrazine and Carbon Monoxide by Selenium

The reaction of monomethylhydrazine with carbon monoxide in the presence of selenium gave a monoselenocarbazic acid salt of methylhydrazine (I), and the reaction of methylhydrazine with a mixture gas of carbon monoxide and oxygen in the presence of I at room temperature gave 4-methylamino-l-methylurazole (III). The structure of III was determined by ¹H NMR and FT ¹³C NMR.     

The preparation and reactions of 1,3,4,5,6,7,8-heptafluoro-2-naphthyl prop-2-enyl ether: Formation of 1,3,4,5,6,7,8-heptafluoro-1-(prop-2-enyl)naphthalen-2-one and the photolysis and pyrolysis of this ketone [1].

1,3,4,5,6,7,8-Heptafluoro-2-naphthyl prop-2-enyl ether (8) was isomerised in boiling xylene to 1,3,4,5,6,7,8-heptafluoro- 1-(prop-2-enyl)naphthalen-2-one (9). Photolysis of (9) gave 2,5,7-trifluoro-3,4-(tetrafluorobenzo)tricyclo[3.3.1.O^2,7]non-3- en-6-one (11) (by a [2 + 2] addition) and 1,2,7-trifluoro-3,4- (tetrafluorobenzo) tricyclo [3.3.1.O^2,7]non-3-en-8-one (12) (via an initial [3,5] photochemically-allowed sigmatropic shift). Pyrolysis of (9) at 455° also gave (11), while at 490°, both (9) and (11) gave 1-fluorovinyl 4,5,6,7,8-pentafluoro-1-naphthyl ketone (19).     

Dipolar additions with 1-(4,6-dimethylpyrimidin-2-yl)- and 1-(4,6-dimethoxy-s-triazin-2-yl)-3-oxidopyridinium betaines

Cycloaddition to 1-(4,6-dimethylpyrimidin-2-yl)- and 1-(4,6-dimethoxy-s-triazin-2-yl)-3-oxidopyridinium betaines across the 2,6-positions of the pyridine rings with indene, acenaphthylene and ethyl cinnamate gave substituted 8-aza[3.2.1]bicycIooct-3-en-2-ones, whereas the [6π + 4π] cycloaddition reaction with 6,6-dimethylfulvene gave a tricyclo[6.3.1.0^2.6]dodeca-2,(6),4,9-trien-11-one. Structural and configurational assignments of the cycloadducts were deduced from ¹H nmr and ir spectral data.     

SYNTHESIS,SPECTROSCOPIC STUDIES,AND X-RAY CRYSTAL STRUCTURE OF N-HETERYLIMINOPHOSPHORANES

N-[2-(α-Bromoacetyl)phenyl]imides (prepared in two steps from 2-aminoacetophenone) gave, upon treatment with sodium azide, fused azidoquinolines via an intramolecular cyclization. Reaction of the above azides with phosphines gave N-heteryliminophosphoranes. The IR, ¹H-, ¹³C-, and ³¹P-NMR and MS spectra of these compounds as well as the x-ray crystal structure of two of them is reported.     

Synthesis of (3S,5R)-cis- and (3S,5S)-trans-3,5-Dimethylvalerolactones and Their Conversion to Biotransformation Products of (S)-5-Ethyl-5-(2′-pentyl)barbituric Acid

(R,S)-5-Ethyl-5-(2′-pentyl)barbituric acid (I)^1,2 is metabolized in vivo to give all four possible optical isomers of 5-ethyl-5-(3′-hydroxy-1′-methylbutyl)barbituric acid (II). ^3,4 From metabolism studies of pure (1′S)- I and (1′3)-I, Palmer and co-workers^4,5 were able to determine the relative amounts of each of the four isomers formed. These studies showed that (1′S)-I gave mainly one enantiomer of (1′S)-II, whereas (1′R)-I gave approximately equal amounts of both (1′R)-II enantiomers.     

Functional polymers. XLIX. Copolymerization of ω-alkenoates with α-olefins and ethylene

The 2,6-dimethylphenyl ester of 10-undecenoic acid was copolymerized with 1-dodecene, 1-octene, 1-hexene, propylene, and ethylene using coordination initiation systems based on “aluminum-activated” titanium trichloride and dialkylaluminum chlorides. The copolymerizations with higher α-olefins proceeded smoothly and gave copolymers incorporating from 60 to 90% of the 10-undecenoate feed. Copolymerization with propylene gave incorporation of 5 mol % of 2,6-dimethylphenyl 10-undecenoate; with ethylene only 3 mol % of the ω-alkenoate was readily incorporated. All copolymers were characterized by elemental analysis, dilute solution viscosity, and by their IR ¹H- and ¹³C-NMR spectra.     

Nucleophilic substitution in the 10,11-dihydrodibenz[b,f]iodepinium cation

10,11-Dihydrodibenz[b,f]iodepinium tetrafluoroborate gave only 1-(2-azidophenyl)-2-(2-iodophenylethane with the N₃ ^– in aqueous DMSO, while with NO₂ ^– it gave 1-(2-nitrophenyl)-2-(2-iodophenyl)ethane (93%), 9,10-dihydrophenanthrene (5%), and traces of phenanthrene. Both in pure and aqueous DMSO this cation with the Br^– ion was converted into phenanthrene (80% and 68% respectively) and 1-(2-bromophenyl)-2-(2-iodophenyl)ethane (10 and 20%), while in water it gave 9,10-dihydrophenanthrene (75%) and phenanthrene (5%). A new route for the synthesis of 1-(2-aminophenyl)-2-phenylethane starting from this tetrafluoroborate has been proposed.M. V. Lomonosov Moscow State University, Moscow 119899, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, 110–115, January, 1999.     

Cation radicals. XXXII. Reaction of N-ethylcarbazole with iodine-silver salts. Nitration of N-ethylcarbazole

Reaction of N-ethylcarbazole ( 1 ) with iodine-silver perchlorate gave a green solution having a singlet esr signal. Reduction of the solution with potassium iodide gave N,N′ -diethyl-3,3′-dicarbazolyl ( 3 , 48%). Small amounts of 3-iodo- ( 4 ) and 3,6-diiodo-N-ethylcarbazole ( 5 ) were also obtained. Compounds 4 and 5 are believed to have been formed by electrophilic iodination of 1 by I₂-AgCIO₄, whereas 3 appears to have been formed via the dimerization of 1 ^.+. In accord with this, reaction of 1 with iodine-silver nitrite gave 3-nitro-N-ethylcarbazole ( 6 , 61%), 9% of another nitro-N-ethylcarbazole ( 7 ), thought to be either 1- or 4-nitro-N-ethylcarbazole, and 28% of 4. Thus, trapping of 1 ^.+ by nucleophilic nitrite ion occurred even though 1 ^.+ is not stable enough toward isolation as the perchlorate.     

Control of photoreactions of eight membered ring di- and trienones in a crystalline inclusion complex with optically active 1,6-DI(o-Chlorophenyl)-1,6-diphenylhexa-2,4-diyne-1,6-diol

By complexing with the title host compound, flipping equilibrium of cycloocta-2,4,6-trien-1-one was frozen in one optical conformer as a 2:1 complex, which upon irradiation gave optically active bicyclo [4.2.0] octa-4,7-dien-2-one. Irradiation of a 1:2 complex of cycloocta-2,4-dien-1-one and the same host compound gave an optically active dimer, anti-tricyclo [8.6.0.0^2,9] hexadeca-7, 11-diene-3, 16-dione.     

Base catalyzed intramolecular cyclization of dialkycrotyl(3-alkenylpropyn-2-yl)ammonium salts and aqueous base fission of 2,2-dialkyl-4-methyl-and 2,2-dialkyl-4,6-dimethyl-2,6,7,7a-tetrahydro-1H-isoindolium bromides

Cyclization of dimethylcrotyl(3-vinyl-or-3-isopropenylpropyn-2-yl)ammonium bromides in the presence of base gave a mixture of the isomeric 2,2-dialkyl-4-methyl-and 2,2-dialkyl-4,6-dimethyl-2,6,7,7a-tetrahydro-1H-isoindolium bromides. Basic fission of the salts obtained at increased temperature gave a mixture of the isomeric N,N-disubstituted di-and trimethylbenzylamines whose structures were confirmed by their IR, ¹H NMR, and ¹³C NMR spectra. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 841–846, June, 2008.     

Nonglycoside analogs of nucleotides

N¹-(2′,3′-Dihydroxypropyl)uracil, -thymine, -cytosine, and N⁹-(2′,3′-dihydroxypropyl)adenine were synthesized by alkylation of nucleic bases with 2,3-O-isopropylideneglycerol chlorohydrin, subsequent separation of the resulting mixtures, and removal of the protective groupings. Phosphorylation of these compounds or of their selectively substituted derivatives gave 2′(3′)-monophosphates, which were converted to 2′,3′-cyclophosphates by reaction with N,N′-dicyclohexylcarbodiimide. Thionation of the corresponding cytosine derivatives gave N¹-(2′,3′-dihydroxypropyl)-4-thiouracil and its 2′(3′) phosphate.