Effective macrophage delivery using RAFT copolymer derived nanoparticles

We use reversible addition fragmentation chain transfer (RAFT) polymerisation to prepare block copolymers that are subsequently assembled into nanoparticles. The prepared nanoparticles were extensively taken up by primary murine macrophages and are effective in the delivery of a cell impenetrable cargo.

Selective Protection Strategies in the Synthesis of TRIS-Fatty Ester Derivatives

A methodology for the selective synthesis of lipophilic acyl derivatives of the glycinamido triol (1) with either one, two, or three fatty ester groups has been established. Peracylation of (1), with palmitoyl chloride gave the triacylated derivative. Conversion of (1) into the acetonide, followed by acylation with either palmitoyl chloride or lauroyl chloride, and acetal hydrolysis provided the monoacylated derivatives. Treatment of (1) with trimethyl orthoacetate gave the orthoacetate derivative. Mild hydrolysis provided the monoacetate/diol. Acylation of the two hydroxyl groups with palmitoyl chloride gave the dipalmitate/acetate. Selective cleavage of the acetate group afforded the dipalmitate of (1). Analogous chemistry with trimethyl orthoformate provided the same dipalmitate via the orthoformate, monoformate/diol, and dipalmitate/formate. A more robust synthesis of the dipalmitate was achieved by converting the hydroxyl group of the acetonide of (1) into a tert-butyldiphenylsilyl ether, followed by acetal hydrolysis, palmitoylation of the liberated hydroxyl groups, and desilylation.

A color-enhanced aid for location of the transverse horizontal opening and closing axis of the mandible

This article describes the use of a device for assisting in identification of the direction of the arc of rotation while locating the transverse horizontal opening and closing axis of the mandible. Translucent disks are mounted on the point of the styli of a kinematic face-bow and centering magnets are aligned with them, with no overlapping of the colors. The direction of the arcing movement is enlarged by the overlapping of the translucent disk over the centering magnet. The different color value generated by the overlapping identifies the arcing direction. After correction on the microadjustable arm, the centering magnet is realigned on the translucent disk. This sequence is repeated until the disk no longer overlaps with the centering magnet during the opening and closing movements of the mandible. This device uses the different color generated by mixing the color of the disk against a template of darker color. The disk enlarges the point of the stylus, thus magnifies the direction of the arc of rotation, and potentially reduces the clinical time necessary to locate the points of pure rotation.

Molybdenum Hexacarbonyl Promoted Ring-Opening of Hydroxyimino Isoxazoles: Unexpected Pyrazole Formation

Fused isoxazoles underwent reductive ring-opening in the presence of molybdenum hexacarbonyl to give the corresponding β-disubstituted compounds. 3,6,6-Trimethyl-6,7-dihydro-1,2-benzisoxazol-4(5H)-one oxime underwent reductive ring-opening in the presence of molybdenum hexacarbonyl to give 3,6,6-trimethyl-6,7-dihydro-1H-indazol-4(5H)-one. A mechanism is proposed.

The Cycloaddition Reactions of Benzimidazole-2-carbonitrite Oxide With Alkenes

Benzimidazole-2-carbonitrile oxide was prepared in situ and reacted with vinyl acetate, acrylonitrile, styrene, phenyl vinyl sulfone and 3,3,3-trifluoropropene to afford 2-(5'-acetoxyisoxazolin-3'-yl)-, 2-[(5'-cyanoisoxazolin-3'-yl)-, 2-(5'-phenylisoxazolin-3'-yl)-, 2-[(5'-phenylsulfonyl)isoxazolin-3'-yl]- and 2-[(5'- ( trifluoromethyl )isoxazolin-3'-yl)]- benzimidazole respectively. 2-(5'-Acetoxyisoxazolin-3'-yl) benzimidazole was converted into 2-(isoxazol-3'-yl) benzimidazole by treatment with triethylamine. The amidoximes derived from unsubstituted and N1-sulfamoyl-substituted 2-cyanobenzimidazoles were prepared but were not preparatively useful as precursors to benzimidazole-2-carbonitrile oxides.

The Synthesis and Biological Activity of 'Crippled Biotin'

(3aα,6β,6aα)-6-Methyltetrahydro-1H-thieno[3,4-b]pyrrol-2(3H)-one (2) was prepared as a crippled analogue of biotin. The key synthetic step involved hydrogenation of 6-methyl-1H- thieno [3,4-b]pyrrol-2(3H)-one on palladium to introduce the necessary all-cis configuration. Both compounds were weak inhibitors of the biotin-dependent wheat acetyl-CoA carboxylase compared to substrates or the potent herbicidal inhibitors of this enzyme, but were more potent than biotin or imidazolidone. Neither compound inhibited the biotin-dependent transcarboxylase component of bacterial acetyl-CoA carboxylase, nor did they significantly inhibit the growth of Arabidopsis thaliana.

Alkylation Reactions of 2-Methylpropyl 3-(2-Methylpropoxy)-5-oxocyclohex-3-ene-1-carboxylate

The anion derived from 2-methylpropyl 3-(2-methylpropoxy)-5-oxocyclohex-3-ene-1-carboxylate was reacted with methyl iodide to give cis and trans isomers of 2-methylpropyl 6-methyl-3-(2-methylpropoxy)-5-oxocyclohex-3-ene-1-carboxylate. The reaction proceeded with high regioselectivity. A combination of n.m.r. experiments was used to determine that the major diastereoisomer was in a trans configuration. The dianion derived from 2-methylpropyl 3-(2-methylpropoxy)-5-oxocyclohex-3-ene-1-carboxylate methylated at C1 and C6 with a roughly equal proportion of cis and trans isomers. When treated with 1 equiv. of 1-bromo-3-chloropropane the same dianion alkylates at C1 to give 2-methylpropyl 1-(3-chloropropyl)-3-(2-methylpropoxy)-5-oxocyclohex-3-ene-1-carboxylate.

Diastereoselective Propionitrile Oxide Cycloaddition Reactions With Some γ-Substituted α-Methylene-γ-butyrolactones

A number of γ-substituted α-methylene-γ-butyrolactone derivatives underwent 1,3-dipolar cycloaddition with propionitrile oxide to give spiro Δ2-isoxazolines. The reaction proceeded regiospecifically and with high diastereoselectivity. The products of anti addition predominated. The regiochemistry of addition and relative stereochemistry of the products were determined by a combination of n.O.e ., HETCOR and DOUBTFUL n.m.r. experiments. The assignment was confirmed in one case by X-ray crystallography.

Further Reactions in the Tetrahydroazocin-2(1h)-one Series

5,6,7,8-Tetrahydroazocin-2(1H)-one and the 3-phenylthio- and 3- phenylsulfonyl-substituted derivatives have been converted into the corresponding 2-ethoxy-5,6,7,8-tetrahydroazocines with Meerwein's reagent. Upon irradiation under mercury lamp at longer wavelengths (Pyrex vessels) these compounds are inert, but at shorter wavelengths (quartz vessels) polymeric materials form with no evidence of intramolecular ring cyclization. Reaction of the lactams with bases, and with t-butyl hypochlorite, are reported, and these reactions lead to a variety of azocin-2(1H)-one derivatives.

The stereochemical assignment of the 1,2-Diphenylbut-3-en-1-ols, (1RS,2RS,3RS)- and (1RS,2RS,3SR)-3,4-Epoxy-1,2-diphenylbutan-1-ols and (2RS,3SR)- and (2RS,3RS)-3,4-Epoxy-1,2-diphenylbutan-1-ones and crystal structure of (1RS,2RS,3RS)-3,4-Epoxy-1,2-diphenylbutan-1-ol

The reaction of the Grignard compound formed from (E)-3-chloro-1-phenylprop-1-ene (2a) with benzaldehyde has been studied and conditions found which allow for the efficient preparation of the diastereoisomeric homoallylic alcohols (4) and (5). The relative stereochemistry of these alcohols along with (1RS,2RS,3RS)- and (1RS,2RS,3SR)-3,4-epoxy-1,2-diphenylbutan-1-ol (6) and (7) and (2RS,3SR)- and (2RS,3RS)-3,4-epoxy-1,2-diphenylbutan-1-ones (8) and (10) has been established and the crystal structure of (1RS,2RS,3RS)-3,4-epoxy-1,2-diphenylbutan-1-ol determined.

Preparations of 3-substituted Tetra- and Hexa-hydroazocin-2(1H)-ones and derivatives

3-Bromo- and 3-chloro-hexahydroazocin-2(1H)-one undergo dehydrohalogenation rather than substitution reactions, even in the presence of weakly basic nucleophiles like iodide and cyanide ions. A mixture of two alkenes is formed, with the conjugated isomer, 5,6,7,8-tetrahydroazocin-2(1H)-one, predominating over the deconjugated isomer. Only thiolate nucleophiles, for example sodium benzenethiolate, gave substitution reactions and the resulting 3-phenylthiohexahydroazocin-2(1H)- one was oxidized to give a mixture of diastereoisomeric sulfoxides. On attempted Pummerer rearrangement, this mixture of sulfoxides afforded 3-phenylthio-5,6,7,8-tetrahydroazocin-2(lH)-one rather than the expected α-acyloxy sulfide.

Asymmetric reductinon of carbonyl compounds by yeast. II. Preparation of optically active α- and β-hydroxy carboxylic acid derivatives

α- and β-Keto esters and amides are readily reduced by an actively fermenting mutant of Saccharomyces cerevisiae and produce optically active α- and β-hydroxy esters and amides in moderate yields. Typically, methyl 2-oxo-2-phenylacetate gave methyl (R)-(-)-2-hydroxy- 2-phenyl- acetate; 2-oxo-2-phenylacetamide gave (R)-(-)-2-hydroxy-2- phenylacetamide; ethyl benzoylacetate gave ethyl (S)-(-)-3-hydroxy-3- phenylpropionate, and ethyl 2-oxocyclohexanecarboxylate gave ethyl (1R,2S)-(+)-2-hydroxycyclohexanecarboxylate. In each case, the product obtained was optically pure. However, the reduction of ethyl pyruvate to ethyl lactate produced partially racemized products.