Stereochemical studies 87saturated heterdcycles 82: Synthesis and steric structure of steredisomeric n-substituted tetrahydro-1,3-oxazines fused with norbornane or norbornene

$\text{diendo}$- and $\text{diexo}$-2-Methylamino and 2-benzylamino-3-hydroxymethylbicyclo [2.2.1]heptanes and the corresponding bicycio [2.2.1] heptenes ($\text{5a}$ -$\text{d}$, $\text{7a}$ -$\text{d}$) were synthesized from β-amino acid esters containing the norbornane or norbornene skeleton ($\text{3a}$-$\text{d}$). The aminoalcohols were converted to 5,8- methano -3,1-benzoxazines by reaction with formaldehyde. As established by ¹H and ¹³C NMR spectroscopy, the predominant conformation is $\text{endo - boat}$ ($\text{B}$) for the $\text{diexo}$, and $\text{exo - boat}$ ($\text{E}$) for the $\text{diendo}$ derivatives.     

Bioactive marine metabolites IX. Mycalisines A and B,novel nucleosides which inhibit cell division of fertilized starfish eggs,from the marine sponge mycale sp.

Two novel nucleosides, mycalisines A and B, have been isolated from a marine sponge and their structures elucidated as 4-amino-5-cyano-7-(3-$\text{O}$-methyl-5-deoxy-β-D-$\text{erythro}$-pent-4-enofuranosyl)-pyrrolo[2,3-$\text{d}$]pyrimidine and 5-cyano-7-(3-$\text{O}$-methyl-5-deoxy-β-D-$\text{erythro}$-pent-4-enofuranosyl)-pyrrolo[2,3-$\text{d}$]pyrimidine-4-one, respectively. Both compounds inhibit cell division of fertilized starfish eggs.     

Obtention de 3 types de derives du bore: esters aminoboriques tris n-boranes,esters amio boriques bis n-boranes et aminalcools n-boranes a partir de la reaction d'aminalcools-1,2 avec BH3.THF et BH3DMS. mise en evidence d'une coordination interner B←N

The reactions of 1,2-aminoalcohols with BH₃.THF or DMS lead to various title compounds, depending on the reaction conditions. The structures have been determined using ¹¹B, ¹H nmr and i.r. spectroscopy and selected reactions. The conclusions differ from previous r$\text{e}$sults: we were in particular able to evidence intramolecular N←B coordination in structures of type $\text{d}$ and $\text{e}$.     

Cycloaddition of single oxygen and triazolinedione (TAD) with spirocyclopentadienyl-1,3,5-cycloheptatrienes1: tropilidene versus norcaradiene reactivity

4-Methyl-1,2,4-triazoline-3,5-dione (MTAD) gives with 7-spiro-fluorenyl-1,3,5-cycloheptatriene ($\text{1d}$) initially he norcaradine-type urazole ($\text{N3d}$) which at ambient temperatures rearranges into ($\text{6d}$), while ¹0₂ gives the tropilidene-type endoperoxide ($\text{T4d}$).     

Emission spectra of supersonically cooled methyldiacetylene cations

The ā²E → X?²E (Σ= + $\text{1}\text{2}$, - $\text{1}\text{2}$) electronic transitions of rotationally/vibrationally cooled CH₃CCCCH^- cation, as well as the d₁-/d₃-/d₄-substituted species, were studied by emission spectroscopy. Ion emission was obtained by electron impact on the neutral species seeded in a helium supersonic free jet. Vibrational frequencies in both electronic states are inferred to within ±1 cm^-1. Spin-orbit splittings are observed and interpreted on the basis of non-linear vibronic couplings. Rotational subbands are observed, yielding rotational and Coriolis parameters as well as rotational temperatures.     

Correlation between the isotropic 29Si chemical shifts and the mean silicon-oxygen bond lengths in silicates

Using known NMR and structural data of solid silicates the linear correlation $\text{δ}\text{-}$ = 1.1$\text{87 × 10}$⁴$\text{d}\text{(SiO)}$ - 2014 between the isotropic ²⁹Si NMR chemical shifts $\text{δ}\text{-}$ (ppm) and the “isotropic” mean bond lengths $\text{d}\text{(SiO)}$ (nm) has been established. The results of semi-empirical calculations are in good agreement with this equation.     

Oxidation with sodium peroxide Direct introduction of a γ carbonyl group into α,β unsaturated ketosteroids

Aqueous sodium peroxide oxidises the conjugated Δ⁴-3-ketosteroids $\text{1a}$-$\text{1d}$ to the corresponding Δ⁴-3-4-diones in good yield. Saturated carbonyl and alcohol groups are not affected by the reaction.     

Substituted cyclononatetraenes and nonafulvenes

Reaction of $\text{cis}$,$\text{cis}$,$\text{cis}$,$\text{cis}$-[9]annulene anion ($\text{1}$) with electrophiles ($\text{2a}$-$\text{d}$) leads to substituted $\text{cis}$,$\text{cis}$,$\text{cis}$,$\text{cis}$-1,3,5,7-cyclononatetraenes ($\text{3a}$-$\text{d}$) which are precursors for the preparation of 10- and 10,10′-donor-substituted nonafulvenes (e.g. $\text{7b′}$$\text{e′}$). The influence of solvent and temperature on the ¹H-nmr spectra of the nonafulvenes $\text{7b′}$-$\text{h′}$ has been investigated.     

Stereochemical studies — 79 synthesis and kinetic study on the retrodiene decomposition of norbornene-condensed 1,3-oxazin-4-ones

The $\text{cis}$-$\text{cxo}$- amino acid $\text{c}$ with norbornene skeleton was converted into 2-aryvl-$\text{cis}$-$\text{cxo}$-1,3-oxazin-4-ones $\text{5a}$-$\text{d}$. These compounds, similarly to the $\text{diendo}$ isomers $\text{1a}$-$\text{d}$ studied by us earlier, undergo retrodiene decomposition under mild conditions to give 2-aryl-6$\text{2}$-l,3-oxazin-6-ones ($\text{2}$$\text{a}$-$\text{d}$) in 50-60% yield. The ratio of the decomposition rate constants of the tricyclic $\text{diendo}$ and $\text{diexo}$-1,3-oxazin-4-ones, measured in toluene solution, is about 2.     

Effect of inorganic aqueous anions on the synergic extraction of cadmium and zinc with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HPMBP) and lipophilic ammonium salts

As a part of a systematic study of the synergic extractions of metals with mixtures of acidic chelating extractants and lipophilic anion-exchangers (B, X with X^?6 inorganic anion), the extractions of M  Cd and Zn from perchlorate, nitrate and sulphate media with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5- one (HL) and tri-n-octylammonium salts (TOAH.X) or aliquat 336 (TOMA.X) in toluene have been investigated. Three key equilibria describe the extractions: (a) M²⁺+2$\text{HL}$?$\text{ML}{}_2$+2H⁺. (b) $\text{B.X}$ +$\text{HL}$?$\text{B.L}$+H⁺+X^? with B efficiency TOMA < TOAH and X efficiency ClO₄ < NO₃ < SO₄. (c) $\text{ML}{}_2$+$\text{B.L}$?$\text{B.ML}{}_3$ with B efficiency toma > TOAH and Ni ～ Co > Cd > ZN.As a consequence of the conflicting orders of efficiencies of TOMA and TOAH in equilibria b and c, TOAH.X is a better synergic extractant from perchlorate medium than TOMA.X whereas the inverse is observed from nitrate and sulphate media. Equilibrium c is independent of the inorganic anions. Constants of equilibria a, b and c are given. B.ML₃ species are not extracted in 1-octanol.     

Polyamides with piperazine units in the polymer chain—I: Crystal structure and molecular packing of poly(1,4 piperazine-trans-4-octen-1,8 dioyl)

The crystal structure of poly(1–4 piperazine-trans-4-octen-1,8 dioyl) has been determined from X-ray fibre spectra. The unit cell parameters are: $\text{α=4.54 A; b = 10.00}\text{A}\text{?}\text{; c =13.50}\text{A}\text{?}$ (fibre axis) β = 110°15′ space group P2₁/n. Z =2, d_x = 1.28 g/cm³ (d_obs = 1.23 g/cm³).The chain symmetry is ti. The value of β ≠ 90° is determined by the necessity of suitably packing the neighbouring paraffinic chains and piperazine rings, at the shortest possible distance. The mode of packing of the paraffinic portions of the chains, in the a direction, is reminiscent of the analogous situation met for polyalkenamers (even series).     

Synthesis and 13C nmr characterization of some π-excessive heteropolyaromatic compounds

Several π-excessive heteropolyaromatic compounds, which contain furan and thiophen ring and are possible antifungal agents, have been synthesized in good yields according to two general methods. The first method has been used to prepare compounds possessing thiophens linked by their 2- and 5-positions, such as the ter-aryls $\text{2b}$, $\text{2d}$ and $\text{2a}$. Two precursors of these compounds have been obtained either by the Glaser reaction, or using a novel Pd-mediated reaction. The second method,which consists of the Ni-or Pd-catalyzed heteroarylation of heteroarene halides via cross-coupling with heteroaryl Grignard reagents or zinc halides,has been used to prepare the bi-aryls $\text{1a-e}$, which contain two heteroaromatic units, and the ter-aryl $\text{2c}$. Compound $\text{1e}$ has been also prepared starting from 2-(2-thienyl) furan ($\text{1c}$) by selective lithiation, followed by bromination.The ¹³C NMR signals of $\text{1a-e}$ and $\text{2a-d}$ have been assigned on the basis of the literature data and by relaxation measurements. Relaxation data have been also used to obtain qualitative informations on the conformational equilibria of the bi-aryls $\text{1a}$, $\text{1c}$ and the ter-aryls $\text{2a-d}$.     

Stekeospecific transformation of D-sugar to L-sugar in complex aminoglycoside. Synthesis of a kanamycin B analog having 2,6-diamino-2,4,6-trideoxy-L-arabino-hexopyranose

A 4′-ene derivative of kanamycin B ($\text{4}$) was derived from the epoxide ($\text{1}$) by oxidative elimination of the 4′-phenylseleno group into the allylic alcohol ($\text{3}$). The title compound, 0-(2,6-diamino-2,4,6-trideoxy-β-L-arabino-hexopyranosyl)-(1→4)-0-[3-amino-3-deoxy-α-D-glucopyranosyl-(1→6)]-2-deoxystreptamine ($\text{6}$) was obtained from $\text{4}$ by stereospecific hydrogenation followed by removal of the masking groups, changing the D-sugar moiety of the 4-0-glycoside portion into an L-sugar.     

Epoxide formation by the photolysis of cyclic oxalate esters

The cyclic oxalate esters from $\text{meso}$- and $\text{d}$, $\text{1}$-hydrobenzoin were prepared and photolyzed. $\text{Meso}$-hydrobenzoin oxalate gave only $\text{cis}$-stilbene oxide upon photolysis while the $\text{d}$, $\text{1}$ isomer gave $\text{trans}$-stilbene oxide.     

Reaction of 2-arylazo-2, 5-dimethyl-3(2H)-furanones with ammonia. Preparation of β-acetyl-β-(3-amino-2-butenoyl) arylhydrazines.

Ring opening of 2-arylazo-2,5-dimethyl-3(2H)-furanones ($\text{1a–d}$) with ammonia leads to previously unknown β-acetyl-β-(3-amino-2-butenoyl)arylhydrazines ($\text{3a–d}$). The reaction mechanism is discussed.     

Untersuchung der Flammenemission von Metallhalogeniden und deren Nutzung zur Analytik der Halogene

Departing from the until now well known A and B systems of the indium and gallium halide emissions the authors tried to find further spectra of molecule bands in flames. The following band systems were observed: InF¹ (A, B and C systems), GaF¹ (A, B and C systems), A1F¹ (A system), T1C1¹, TlBr¹, TII¹ and the C systems of the GaCl, GaBr, InCl and InBr molecules.From the behaviour of the intensities of excited and nonexcited MeX species and the existence of InF-C bands (excitation energy 5.30 eV) in the hydrogen-nitrogen diffusion flame it could be derived that the excited state results from the reaction of metal and halogen atoms. Furthermore the experimental results of MeX intensity measurements indicate reactions of excited molecules with particles of flame gases. This is especially valid for the A and B systems of the indium and gallium halides (triplet states) which have as a result of the forbidden transitions a relatively long life time. Using other gas mixtures (Hr-air, propane-air) and observation of CuX and alkaline earth halide bands as well gave the possibility to set up a block diagram of optimum conditions for measuring the different MeX emissions.Examination of the analytical performance gave detection limits of 0.7 $\text{mg}\text{l}$ for F^?1 and about 4 $\text{mg}\text{l}$ for Cl^?, Br^? and I^? by means of InX emissions. The limits of the concentration ratios for the determination of traces were 1:640 (Cl^? in HBr) up to 1:60,000 (I^? in HF). The best determinations of other halogens are possible in HC1 and HF matrices.     

A new optical resolution method of tertiary acetylenic alcohol utilizing complexation with brucine

Some tertiary acetylenic alcohols were resolved efficiently utilizing complexation with brucine. The crystal structure of 1:1 brucine complex of 1-(o-bromophenyl)-1-phenyl-2-propynol ($\text{1}$$\text{d}$) was reported.