Synthesis of vitamin B6 derivatives. III. 3- (4-formyl-3-hydroxy-2-methyl-5-pyridyl)propionic acid,an analog of pyridoxal phosphate

The preparation and properties of a new analog of pyridoxal phosphate, 3- (4-formyl-3-hydroxy-2-methyl-5-pyridyl)propionic acid and of the corresponding 4-aminomethyl compound are described. The n.m.r. spectrum of the new aldehyde is compared with those of 5-deoxypyridoxal and pyridoxal phosphate. The broad aldehyde proton peak of 5-deoxypyridoxal is sharpened by heating, suggesting an equilibrium between two geometrical isomers. Mass spectra of the new aldehyde and of 5-deoxypyridoxal are analyzed. The electronic absorption spectrum is nearly the same as that of 5-deoxypyridoxal. The new aldehyde undergoes rapid transamination with amino acids, and the corresponding aminomethyl compound can be reoxidized to the aldehyde by heating with glyoxylic acid in aqueous solution.     

Tetracyclines Communication 21. Synthesis of 2- and 3-substituted 10-oxo-9-hydroxy-9-methyl-1,2,3,4,4a,9,9a,10-octahydroanthracenes

Summary Various 10-oxo-9-hydroxy-9-methy 1-1,2,3,4,4a,9,9a,10-octahydroanthracenes were synthesized; they are analogous in structure to the DCB ring system of tetracyclines and have active functional groups in the 2- and 3-positions (halogen atoms, the epoxy group, hydroxyl, and ketonic carbonyl), which creates the potentiality of the further introduction of suitable substituents and then the building up of the fourth ring of tetracyclines.For communication 20 see [1].The authors are deeply indebted to L. B. Senyavina for the measurement of infrared spectra.Translated from Izvestiya Akademii Nauk SSSR, Setiya Khimicheskaya, No. 6, pp. 1013–1024, June, 1964     

Tetracyclines Communication 22. Stereochemistry of 2- and 3-substituted 10-oxo-9-hydroxy-9-methyl-1,2,3,4,4a,9,9a,10-octahydroanthracenes

Summary Intramolecular cyclization reactions were investigated, and the configurations were proved of 2- and 3-substituted 10-oxo-9-hydroxy-9-methyl-1,2,3,4a,9,9a.10-octahydroanthracenes of type (I), which are possible intermediaries for the synthesis of tetracyclines and their analogs.Translated from Izvestiya Akademii Nauk SSSR, Setiya Khimicheskaya, No. 6, pp. 1024–1035, June, 1964     

Copper complex protection in the regioselective alkylation of methyl 3,5-dioxohexanoate. Preparation of 3-alkyl derivatives of 4-hydroxy-6-methyl-2-pyrone

Protection of the diketone moiety of the polyketide model methyl 3,5-dioxohexanoate by copper(II) complex formation followed by alkylation of the free C-2 position results in overall regioselective alkylation of the diketoester to afford methyl 2-alkyl-3,5-dioxohexanoates, which under cyclization afford 3-alkyl derivatives of triacetic acid lactone.     

A new synthesis of serricornin [(4s,6s,7s)-7-hydroxy-4,6-dimethyl-3-nonanone], the sex pheromone of the cigarette beetle

Serricornin, the sex pheromone of Lasioderma serricorne F, was synthesised in 7.6% overall yield starting from methyl (R)-3-hydroxypentanoate of microbial origin. Its (4R,6S,7S)-isomer was also synthesised.     

Molecular structure of complexes with a bifurcated hydrogen bond. 5. Dimers of 3-hydroxy-2-methyl-4-pyrone in inert media

According to the data from IR spectroscopy and quantum-chemical calculations (B3LYP/6-31G**, B3LYP/6-311G*), in the vapor and in dichloroethane the synperiplanar conformer of 3-hydroxy-2-methyl-4-pyrone (maltol) exists in equilibrium with two types of dimers. The hydrogen atom of the hydroxy group of one them participates in the formation of a three-center bifurcated hydrogen bond. The second isomer is formed by means of two such H bonds, the intramolecular component of which is substantially weakened while the intermolecular component is so strong that it approximates in character to a two-center hydrogen bond. Dedicated to Academician of the Russian Academy of Sciences M. G. Voronkov on his 85th birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1635–1646, November, 2006.     

Syntheses of apogalanthamine analogs as α-adrenergic blocking agents. IX. Syntheses of optically active 8-hydroxy-6-methyl-5,6,7,8-tetrahydrodibenz[c,e]azocines

(8R) and (8S)-Hydroxy-6-methyl-5,6,7,8-tetrahydrodibenz[c,e]azocines (R- and S- 1 ) were synthesized by oxidative kinetic resolution of N-(2-iodobenzyl)-β-(2-iodophenyl)ethanolamine ( 8 ), followed by cyclization of the optically active acetates (R- and S- 6 ) of R- and S- 8 with zero-valent nickel to (8R)- and (8S)-acetoxyazocines (R- and S- 7 ), and by hydrolysis of the acetates ( R - and S- 7 ).     

Expeditious synthesis of 2,3-dihydro-2-alkoxy-3-methylenebenzofurans from N-benzofuran-3-ylmethyl N,N,N-trialkylammonium bromides: a new approach to access the natural product, 2-hydroxy-3-methylene-6-methyl-2, 3-dihydrobenzofuran

A highly efficient strategy was developed to construct a natural product-based library of 2-alkoxy-3-methylene-2,3-dihydrobenzofurans from N-benzofuran-3-ylmethyl N,N,N-trialkylammonium bromides.     

Synthesis and activity of a metabolite of (S)-6-amino-5-(6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamido)-3-methyl-1-phenyl-2,4-(1H,3H)-pyrimidinedione (CX-659S)

CX-659S (1) [(S)-6-amino-5-(6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamido)-3-methyl-1-phenyl-2,4-(1H,3H)-pyrimidinedione], has been developed as a new type anti-inflammatory agent for the treatment of dermatitis. The structure of a major metabolite of CX-659S was determined as (S)-6-amino-5-[2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxo-1,4-cyclohexadienyl)butanamide]-3-methyl-1-phenyl-2,4-(1H,3H)-pyrimidinedione (2) by direct comparison with the synthesized authentic compound. The anti-inflammatory activity of 2 was equipotent with that of 1 on the contact hypersensitivity reaction (CHR) induced by picryl chloride (PC) in mice, suggesting that compound 2 contributes, at least in part, to the anti-inflammatory activity of CX-659S.     

A synthetic approach for (S)-(3-benzyl-3-methyl-2,3-dihydro-benzofuran-6-yl)-piperidin-1-yl-methanone,a selective CB2 receptor agonist

(S)-(3-Benzyl-3-methyl-2,3-dihydro-benzofuran-6-yl)-piperidin-1-yl-methanone, a selective CB2 receptor agonist, was obtained from 3-hydroxy-4-iodo benzoic acid in nine steps with 97.4% ee and 3.4% total yield, which involved palladium catalyzed tandem intramolecular Heck/Suzuki cross coupling reaction, chemical resolution with (+)-norephedrine and Wolf–Kishner reaction as the key steps. (S)-(3-Benzyl-3-methyl-2,3-dihydro-benzofuran-6-yl)-piperidin-1-yl-methanone will be evaluated in vivo studies and this approach will be applied in the optimization process of CB2 receptor agonist.     

Spectrophotometric determination of cobalt in a vitamin, alloys and an ore by extraction of its 3-hydroxy-2-methyl-1,4-naphthoquinone 4-oxime complex into molten naphthalene

A selective spectrophotometric method has been developed for the determination of cobalt after extraction of its 3-hydroxy-2-methyl-1,4-naphthoquinone 4-oxime (HMNQM) complex into molten naphthalene. The optimum pH range for the extraction is 5.0-7.5. The solidified naphthalene, containing the cobalt-HMNQM complex, is separated by filtration and dissolved in N,N-dimethylformamide. The absorbance is measured at 430 nm against a reagent blank. Beer's law is obeyed up to 1.90 ppm cobalt. The molar absorptivity is 2.09 x 10(4) l.mole(-1).cm(-1).     

Efficient chemoenzymatic synthesis of (2S,3R)-3-hydroxy-3-methylproline,a key fragment in polyoxypeptin A and FR225659

We report an efficient synthesis of protected (2S,3R)-3-hydroxy-3-methylproline that proceeds in three steps with complete stereoselectivity. This route represents a significant improvement over previous approaches to this noncanonical amino acid. Key to this success is the development of a one-pot chemoenzymatic procedure for the preparation of (2S,3S)-3-methylproline from l-isoleucine. This work lays the foundation for future chemoenzymatic syntheses of polyoxypeptin A and FR225659.     

Determination of the stereochemistry of 2-succinyl-5-enolpyruvyl-6-hydroxy-3- cyclohexene-1-carboxylate, a key intermediate in menaquinone biosynthesis

The turnover product of the committed step of menaquinone biosynthesis was isolated and determined to be (1R,2S,5S,6S)-2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate. Structural determination of this key intermediate represents a critical step to complete elucidation of the biosynthetic pathway.     

Ion trap mass spectrometry affords advances in the analytical and atmospheric chemistry of 2-hydroxy-2-methylpropanal,a proposed photooxidation product of 2-methyl-3-buten-2-Ol

In the western United States, in areas where emissions of the biogenic hydrocarbon, 2-methyl-3-buten-2-ol (MBO) are high, MBO contributes significantly to the oxidative capacity of the atmosphere. Hydroxyl radical oxidation of MBO can play an important role in forming tropospheric ozone, and MBO reaction products may contribute to the formation of secondary organic aerosols [1-3]. Although 2-hdyroxy-2-methylpropanal was tentatively identified as a product from the reaction of MBO with .OH in indoor chamber studies, the identity of the compound was not confirmed due to the lack of an authentic standard. Further, no data exists on the atmospheric generation and fate of 2-hydroxy-2-methylpropanal in the ambient environment. Herein, we provide further evidence that 2-hydroxy-2-methylpropanal is generated by .OH reaction with MBO by identifying 2-hydroxy-2-methylpropanal in an indoor chamber experiment and in ambient air sampled in the Blodgett Forest, where MBO emissions are high. We analyzed 2-hydroxy-2-methylpropanal by using a method that relies on O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and bis-(trimethylsilyl) trifluoroacetamide (BSTFA) derivatization along with ion-trap mass spectrometry. Tentative identification of 2-hydroxy-2-methylpropanal was possible by using knowledge gained in this study regarding the mass spectrometry of PFBHA-BSTFA derivatives of carbonyls with primary, secondary, and tertiary -OH groups, and ado- and keto-acids. The identification was confirmed by comparing the methane CI mass spectra and relative gas chromatographic retention time obtained by analyzing 2-hydroxy-2-methylpropanal in a sample extract and a synthesized authentic standard. Since the standard became available at the end of this study (after all samples were analyzed), we also developed a method for semi-quantification of 2-hydroxy-2-methylpropanal, with a detection limit of 27 pptv in air. We used the method to provide the first ambient air measurements of 2-hydroxy-2-methylpropanal. The analyte is not commercially available, and hence other researchers who have not synthesized an authentic standard can employ the method.     

Novel,Simple, and Efficient Synthesis of 3-(2-(5-(Benzylideneamino)-3-phenyl-1H-pyrazol-1-yl)thiazol-4-yl)-4-hydroxy-6-methyl-2H-pyran-2-one Derivatives via a One-Pot,Four-Component Condensation Reaction

The synthesis of 3-(2-(5-(benzylideneamino)-3-phenyl-1H-pyrazol-1-yl)thiazol-4-yl)-4-hydroxy-6-methyl-2H-pyran-2-one derivatives was achieved through a one-pot, four-component reaction involving condensation of 3-(2-bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, thiosemicarbazide, phenacylcyanaide, and various aryl aldehydes in dry alcohol and few drops of acetic acid under reflux condition. This four-component reaction has some advantages such as ease of handling, good yields, and easy workup. All structures of newly prepared compounds were confirmed by analytical and spectral data.