Carbon nucleophilic displacements on kamiya's azetidinone disulfide: Synthesis of c-2 modified penicillins

Novel carbon nucleophilic displacement reactions on Kamiya's azetidinone disulfide $\text{2}$ and the synthesis of the C-2 modified penams $\text{25}$, $\text{26}$ and $\text{27}$ from the intermediates $\text{8}$, $\text{9}$, and $\text{11}$ are described.     

[O9,24] [2.1.2.1] metacyclophane-9-ene,a “twin cyclophane”, and its dehydrogenation products - synthesis structure determination and 1H-NMR-spectroscopy

The synthesis of [O⁹,24] [2.1.2.1]metacyclophane-9-ene and of its dehydrogenation products^the new pyrenocyclophanes $\text{8}$, $\text{10}$, $\text{11}$, and $\text{12}$, is described; their structures are discussed in connection with their ¹H-NMR-spectra.     

Synthesis of 26,26,26-trifluoro-25-hydroxy and 27-nor-26,26,26-trifluoro-25-hydroxyvitamin D3

Two new fluorinated 25-hydroxyvitamin D₃ analogs, 26,26,26-trifluoro- 25-hydroxy ($\text{1}$) and 27-nor-26,26,26-trifluoro-25-hydroxyvitamin D₃ ($\text{2}$), were prepared from 24-phenylsulfonyl 25,26,27-triorcholest-5-en-3β-yl tetrahydropyranyl ether ($\text{3}$).     

Per - bicyclophosphoranylation d'alditols

Reaction of bicyclophosphane $\text{1}$ with glycol $\text{2}$, glycerol $\text{3}$, erythritol $\text{4}$, L(-)arabitol $\text{5}$ and dulcitol $\text{6}$ leads to the corresponding per-alkoxybicyclophosphoranes $\text{2p}$ - $\text{6p}$ which are in tautomeric equilibrium with the phosphates forms $\text{2p}$′ - $\text{6p}$′.The amount of these latters increases regularly from traces to 24%.     

Nucleosides-126: Selective methylation of the C-nucleoside, ψ-isocytidine and its 2$́-deoxy analog. Synthesis of 1-methyl, 3-methyl and 4-o-methyl derivatives

Methods were developed to prepare 1 -methyl-, 3-methyl- and 4-0-methyl-ψ-isocytidine by selective methylation.3$\text{,}\text{?}$5$\text{-}\text{?}$O-Tetraisopropyldisiloxanyl-ψ isocytidine (8) was trimethylsilylated and then treated with MeI and, after deprotection, 1 -methyl-ψ isocytidine (6) was obtained. The 2$\text{-}\text{?}$deoxy analog (7) was also prepared in a similar manner from the 2$\text{-}\text{?}$deoxy analog (10) of 8. Treatment of 8 with CH₂N₂ afforded the 3-methyl-ψ-isocytidine derivative (19) as the major product. Methylation with diazomethane also occurred mainly on N3 of the 2$\text{-}\text{?}$deoxy analog 10 to form 20. Removal of the 3$\text{,}\text{?}$ 5$\text{-}\text{?}$O-protecting group from 19 and 20 afforded 3-methyl-ψ-isocytidine (14) and its 2-deoxy analog (15), respectively. 2-N-Acetyl- 3$\text{,}\text{?}$5$\text{-}\text{?}$O-tetraisopropyldisiloxanyl-ψ-isocytidine (24), on the other hand, gave the 4-O-methyl derivative (25) as the major product upon CH₂N₂ treatment. Subsequent deprotection of 25 afforded 4-O-methyl-ψ-isocytidine (29). aiv51b1p33b     

Four novel C28 sterols from lobophytum depressum

Four novel polyoxygenated C₂₈-sterols have been identified from the soft coral $\text{L. depressum}$ (the Gulf of Eilat, the Red Sea): the 22,28-lactol of 24-methylcholest-5-en-3β,22(R),25-triol-28-al ($\text{1}$), 24-methylcholest-5-en-3β,22(R),25,28-tetraol($\text{2}$) and the corresponding 5,6β-epoxides ($\text{3}$ and $\text{4}$).     

Stereoselective synthesis of (25R)-25,26-dihydroxy-23-oxovitamin D3 and its enzymatic conversion to (25R)-1α,25,26-trihydroxy-23-oxovitamin D3, a putative metabolite of vitamin D3

(25$\text{R}$)-25,26-Dihydroxy-23-oxovitamin D₃ was synthesized efficiently and stereoselectively, and it was converted enzymatically to (25$\text{R}$)-1α,25,26-trihydroxy-23-oxovitamin D₃, a putative metabolite of 1α,25-dihydroxyvitamin D₃. The spectral and chemical properties of (25$\text{R}$)-25,26-dihydroxy-23-oxovitamin D₃ and its 1α,hydroxylated derivative disagree with those reported for the isolated metabolite.     

Steroidal antifeedants from the dorid nudibranch Aldisasanguineacooperi

Two steroids, 3-oxo-chol-4-ene-24-oic acid ($\text{2}$) andi ts unsaturated analog $\text{4}$ have been isolated from the dorid nudibranch $\text{Aldisa}$$\text{sanguinea}$$\text{cooperi}$, and the acid $\text{2}$ has been shown to have antifeedant properties.     

Phospholipid studies of marine organisms 9. New brominateddemospongic acids from the phospholipids of two petrosia species

Two Novel long chain fatty acids, (5Z, 9Z)-6-bromo-25-methyl-5,9-hexacosadienoic and (5Z, 9Z)-6-bromo-24-methyl-5,9-hexacosadienoic acids were found in the phospholipids of $\text{Petrosia}$$\text{ficiformis}$ and $\text{P.}$$\text{hebes}$. Their structures were elucidated with the help of CI-EI7MS and a homogeneous hydrogenation catalyst.     

Condensed cyclic and bridged-ring systems : part 12: A novel synthetic route to 4-p-methoxyphenyl-bicyclo[ 2.2.2 ]octan-2-ones and some bicyclo [ 3.2.1 ] octane derivatives by acid-catalyzed intramolecula

The efficacy of a new acid-catalyzed intramolecular C-alkylation has been demonstrated by the synthesis of 1-methyl-4-$\text{p}$-methoxyphenylbicyclo [2.2.2] octan-2-one ($\text{5}$) and 4-$\text{p}$-methoxyphenylbicyclo [2.2.2] octan-2-one ($\text{6}$) from easily accessible starting materials. The carbinol $\text{20}$, derived from $\text{5}$, undergoes facile rearrangement leading to 1-$\text{p}$-methoxyphenyl-4-methyl bicyclo [3.2.1] oct-3-ene ($\text{22}$), which has been transformed to $\text{endo}$-1-$\text{p}$-methoxyphenyl-4-methylbicyclo [3.2.1] octan-3-one ($\text{25}$).     

Structural effects on valence tautomerism : VII. An NMR and molecular mechanics study of the steric effects of t-butyl substituents on the cycloheptatriene-norcaradiene equilibrium of 7-cyano-7-m

7-Cyano-7-methylcycloheptatrienes containing one t-butyl group on the 1-position ($\text{2}$) or two t-butyl groups on the 1- and 3-, 1- and 4-, or 1- and 5-positions ($\text{3}$, $\text{4}$, or $\text{5}$, respectively) were synthesized and their cyclo- heptatriene (CHT)-norcaradiene (NCD) equilibria measured by variable-temperature ¹H NMR for CS₂-CD₂Cl₂ solutions. The ¹H NMR chemical shifts of the 7-methyl group indicate that these compounds are composed of essentially one CHT and one NCD tautomer with an endo geometry of the methyl group. The introduction of a t-butyl group at the 1-position of 7-cyano-7-methylcycloheptatriene ($\text{1}$) markedly shifts the equilibrium to the NCD side and the addition of the second t-butyl group further favors the NCD form, with the NCD populations for $\text{2}$, $\text{3}$, $\text{4}$, and $\text{5}$ at 25 °C 70.9, 96.5, 92.3, and 99.3%, respectively. An application of molecular mechanics (MMPI) calculations to various t-butylated CHT-NCD systems suggests that the t-butyl groups sterically destabilize the CHT form more than the NCD form, bringing about increased NCD populations.     

Gas chromatographic stationary phase properties of two room-temperature liquid organi salts

The gas chromatographic properties of two room-temperature liquid organic salts, triethyl-n-hexylammonium triethyl-n-hexylboride (TEHAB) and stearylmethyldipolyoxethyl(15)ammonium chloride (Ethoquad $\text{18}\text{25}$, are described. Triethyl-n-hexyl-ammonium triethyl-n-hexylboride could be used up to temperatures of 130°C but showed poor stability towards air and undesirable reactivity towards some dipolar and proton donor/acceptor solutes when used as a column packing material. In contrast, Ethoquad $\text{18}\text{25}$ had a maximum column operating temperature of 280°C, or 300°C after vacuum conditioning. From a calculation of mcReynolds' phase constants and the molar free energy, enthalpy, and entropy of solution for polarity test probes, it was established that Ethoquad $\text{18}\text{25}$ showed intermediate selectivity for dipolar and proton-donor solutes compared to results for conventional non-ionic phases. Ethoquad $\text{18}\text{25}$ is an excellent phase for the profiling of essential oils.     

A new steroidal lactone with plant growth-regulatory activity from dolichoslablab seed

A new plant growth-promoting sterol was isolated from immature seeds of $\text{Dolichos}$$\text{labla}$. The structure was elucidated as (22$\text{R}$, 23$\text{R}$-2α, 3α, 22, 23-tetrahydroxy-B-homo-7-oxa-5α-ergost-24(28)-en-6-one $\text{1}$.     

Syntheses totales de la (+) iso β-peltatine

α-Hydroxyalkylation of a β-(alkoxy 3,4-methylenedioxy benzyl)-γ-butyrolactone ($\text{17}$ or $\text{25}$) with 3,4,5-trimethoxybenzaldehyde or syringaldehyde $\text{27}$, followed by cyclisation, afforded good yields of the corresponding (±) isopeltatines.     

Mechanism of campesterol demethylation in insect

[24-²H]-, [25-²H]-, and [23,23,25-²H₃]-24ξ-methylcholesterol as well as [23,23,25-²H₃]-24-methylenecholesterol were metabolized in the silkworm $\text{Bombyx}$$\text{mori}$ to cholesterol containing zero, one, three and three deuterim, respectively.     

The resolution of racemic 2-alkyl-1-aminocyclopropane-1-carboxylic acids

Practical procedures for the resolution of racemic modification of (1$\text{R}$, 2$\text{S}$)-and (1$\text{S}$, 2$\text{R}$)-1-amino-2-ethylcyclopropane-1-carboxylic acid $\text{1a}$,$\text{b}$,(1$\text{R}$, 2$\text{S}$)- and (1$\text{S}$, 2$\text{R}$)-1-amino-2-methylcyclopropane-1-carboxylic acid $\text{2a}$,$\text{b}$, and (1$\text{R}$, 2$\text{R}$)- and (1$\text{S}$, 2$\text{S}$)-1-amino-2-methylcyclopropane-1-carboxylic acid $\text{3a}$,$\text{b}$ are described; the structures as $\text{1a}$,$\text{2a}$, and $\text{3a}$ were confirmed by X-ray-crystallographic methods.     

Pyridazines XXIV: Application of radicalic ethoxycarbonylation to the synthesis of pyridazine mono- and polycarboxylic acid esters

Reactivity of pyridazines $\text{1}$, $\text{2}$, $\text{3}$, $\text{16}$ towards ethoxycarbonylradical (generated by redox decomposition of oxyhydroperoxide of ethylpyruvate) was studied. Application of this type of homolytic substitution for synthesis of hitherto not accessible pyridazine carboxylic acid esters $\text{6}$, $\text{8}$, $\text{9}$, $\text{12}$, $\text{13}$, $\text{14}$, $\text{15}$, $\text{17}$ is demonstrated. In addition improved synthesis of diethyl 4,5-pyridazinedicarboxylate ($\text{5}$) is proposed.     

N-halogeno-compounds. Part II [1]. N.M.R. data for polyfluorocyclohexadienylideneamines obtained via N- chlorination of polyfluoroarylamines

N.m.r. parameters for nine (I-IX) $\text{N}$-chloropolyfluorocyclohexa-2,5-dienylideneamines are reported and discussed; the magnitudes of the FF-coupling constants fall into the following ranges:

$\text{J}$₁₂ 0-2.8; $\text{J}$₁₃, $\text{J}$₃₅ 6.0-6.8; $\text{J}$₁₄ <1; $\text{J}$₁₅ 0-2.6; $\text{J}$₂₃, $\text{J}$₃₄ 25.5-27.2; $\text{J}$₂₄ 0-6.0; $\text{J}$₂₅ 0-1.2; $\text{J}$₄₅ 5.4-9.8 Hz (I) X = Y = Z = F; (II) X = OMe, Y = Z = F; (III) X - CF₃, Y = Z = F; (IV) X = Ph, Y = Z = F; (V) X = Cl, Y = Z = F; (VI) X = Br, Y = Z = F; (VII) X = Y = F, Z = Cl; (VIII) X = Y = F, Z = Br; (IX) X = Z = F, Y = H. The spectra of $\text{N}$-methyl-4-chloropentafluorocyclohexa-2,5-dienyldeneamine have also been analysed. All the imines examined are configurationally stable at the nitrogen atom.     

Mechanisms for reactions of halogenated compounds. Part 4.[1] activating influences of ring-nitrogen and trifluoromethyl in nucleophilic aromatic substitution

Rate constants have been measured for the reactions of ammonia with various fluorinated pyridines and diazines in aqueous dioxan at 25°. From the results the activating effects of ring-nitrogen (relative to CH) and of trifluoromethyl (relative to -H) have been determined. Ring-nitrogen activates the system at points $\text{ortho}$-, $\text{meta}$- and $\text{para}$- to the point of substitution, in the ratios $\text{ortho}$- 6.2 × 10⁴, $\text{meta}$- 8.5 × 10², and $\text{para}$- 2.3 × 10⁵. Similarly a trifluoromethyl substituent is activating by a factor of 2.4 × 10³$\text{ortho}$- and 4.5 × 10³$\text{para}$- to the point of substitution.