1-Oxo-1,3-dithiolanes--synthesis and stereochemistry.

1-Oxo-1,3-dithiolane (4) and its cis- and trans-2-methyl (5,6), -4-methyl (7,8) and -5-methyl (9,10) derivatives were prepared by oxidizing the corresponding 1,3-dithiolanes (1-3) with NaIO(4) in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with (1)H and (13)C NMR spectroscopy and molecular modelling.

3-Oxo-1,3-oxathiolanes-synthesis and stereochemistry.

The compound 3-oxo-1,3-oxathiolane (6) and its cis - and trans - 2-methyl (7,8), 4-methyl (9,10), 5-methyl (11,12) and 2-p-nitrophenyl (13,14) derivatives were prepared by oxidizing the corresponding 1,3-oxathiolanes (1-5) with NaIO4 in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with 1H NMR spectroscopy and molecular modeling.

Diastereochemical differentiation of beta-amino acids using host-guest complexes studied by Fourier transform ion cyclotron resonance mass spectrometry.

Host-guest complexes where tetraethyl resorcarene was the host molecule were used to study the stereoselectivity of diasteromeric pairs of di-endo- and di-exo-2,3-disubstituted norbornane and norbornene amino acids by ion-molecule reactions and collision-induced dissociation with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Both methods showed stereoselectivity for the diastereomeric pairs. Particularly high selectivity was achieved for di-endo- and di-exo-2,3-disubstituted norbornane amino acids with ion-molecule reactions.

Does the electron ionization induced fragmentation of partly saturated stereoisomeric pyrrolo- and isoindoloquinazolinones show stereospecificity?

The electron ionization mass spectrometric behavior of pyrroloquinazolinones (1-6) and isoindoloquinazolinones (7-14) was studied. These compounds were further classified as partly saturated pyrroloquinazolinones (1-3), benzologues (7-11), methylene-bridged derivatives (4-6, 12, 13) and a bisacyl compound (14). The mass spectra of the pyrrolo- and isoindoloquinazolinones did not exhibit stereospecific retro-Diels-Alder (RDA) fragmentations.

Stereospecific fragmentations in the mass spectra of stereoisomeric isoindoloquinazolines.

The mass spectrometric behavior of stereo- and regioisomeric, partially saturated isoindoloquinazolines was studied by positive-ion electron ionization (EI) and fast-atom bombardment (FAB/LSIMS) mass spectrometry combined with collision-induced dissociation (CID). A highly stereospecific retro-Diels-Alder process was observed in the cyclohexene-fused isomers under the EI conditions, and a corresponding (although less specific) fragmentation was observed in their FAB spectra. In the absence of RDA fragmentations, regio- and stereoisomers of the cyclohexane-fused heterocycles could be distinguished based on their FAB/CID spectra.

[Challenges in chemistry: color reactions, cycloadditions and cycloreversions].

New colour reactions for the identification of drug compounds have been devised. For example, butazolidine is oxidized with permanganate in basic medium to azobenzene and butyric acid; after reduction and coupling, the former is transformed to a red azodye. On nitration, gluthetimide gives the p-nitrophenyl derivative and a second nitro group is substituted at position 3.

1H, (13)C, and (15)N NMR stereochemical study of cis-fused 7a(8a)-methyl and 6-phenyl octa(hexa)hydrocyclopenta[d][1,3]oxazines and [3,1]benzoxazines.

Four 7a-methyl octa(or hexa)hydrocyclopenta[d][1,3]oxazines, five 8a-methyl octa(or hexa)hydro[3,1]benzoxazines, two 6-phenyl hexahydro[3,1]benzoxazinones, and 8a-methyl hexahydro[1,3]benzoxazinone, all cis-fused, were prepared and their stereostructures studied by various one- and two-dimensional (1)H, (13)C, and (15)N NMR spectroscopic methods. In solution, the cyclopentane-fused 2-oxo derivatives and the 1,3-benzoxazinone were found to attain exclusively the N-in/O-in conformation, whereas the 6-phenyl 2-oxo/thioxo derivatives were found to be present predominantly in the N-out conformation. The C-2 unsubstituted and the 2-oxo/thioxo 7a/8a-methyl derivatives were all present in solution as a rapidly interconverting equilibrium of the N-in and N-out conformations.

[Preparation and steric structure elucidation of saturated or partially saturated isoindolo[2,1-a][3,1]benzoxazinones, -[1,2-b][2,4]benzoxazepinones, cyclopentane- and -cyclohexane[b]pyrrolo[2,1-a][3,1]-benzoxazines].

The reactions of 2-carboxybenzaldehyde (1) with 1,3- or 1,4-aminoalcohols (2a-i, 3a,b) were used to prepare partially or fully saturated tetra- and pentacyclic compounds containing a condensed 1,3-oxazino- or oxazepinoisoindolone moiety and one terminal saturated carbocycle. Isoindolo[2,1-a][3,1]benzoxazinones (4a-d, 6, 7), stereoisomeric isoindolo[1,2-b][2,4]benzoxazepinones (5a-c) hexahydrocyclopentane[b]pyrrolo[1,2-a][3,1]-benzoxazinone (10a,b), octahydroindolo[1,2-b]- and decahydroindolo[1,2-a]benzoxazinone (11a,b and 12a,b) and related pentacyclic derivatives (4e-g) were prepared. The diastereomers 5a-c differ in the ring annelation or in the position of the NCHO hydrogens and annelational hydrogens.

Arthrodesis of the septic ankle joint.

In chronic septic complications of the ankle joint bony fusion can be achieved with radical resection of necrotic tissues, special positioning of the foot and extrafocal stabilisation. For non-cooperative patients with bland infections intramedullary stabilisation can be used after which early full weight bearing is possible. The correct technique of operation together with adjuvant therapy with a Septopal chain increases the healing chances of patients and reduces the time and costs of therapy.

Late results of fractures and pseudoarthroses of the leg after tibiofibular synostosis.

The authors present the late results of 10 male patients with open leg fractures and nonunions treated between 1978 and 1985 with tibiofibular synostosis. This was achieved by autologous cancellous bone grafting. The average time of the follow-up study was 11 years at which time all patients were free of fistulas, fully weight-bearing and able to work.

Prevention of recurrent infection after removal of intramedullary metal of the infected femur and tibia.

Prevention of recurrence after consolidation of infected femur and tibia fractures and nonunions is based on two principles. First necrotic bone is eliminated with reaming and rinsing the intramedullary canal after metal removal. As missing inramedullary tissue granulates gradually, prevention of retention cavities is achieved by a drainage tube that is gradually removed in the direction of gravity.

[Preparation and steric structure of condensed-skeleton saturated diphenyl-substituted isoindolones].

The Friedel-Crafts reaction of benzene with cis-4-cyclohexene-1,2-dicarboxylic anhydride (1) yields trans-5-phenyl-cis-2-benzoylcyclohexanecarboxylic acid (2), which gave cyclohexane-condensed pyridazinone (3) with hydrazine, and cis-4,5-tetramethylene-1,2-oxazin-8-one (4) with hydroxylamine. From 2 with ethylenediamine, the saturated imidazol[2,3-a]iso-indolone (5) was prepared, while the reaction of 2 with 1,3-diaminopropane furnished a mixture of two isomeric pyrimido[2,3-a]isoindolones (6a,b) in the relative positions of the benzene ring and cyclohexane annelation hydrogens. From the reaction of 2 with 3-aminopropanol, the oxazino[2,3-a]isoindolone (7) was obtained.

Electron impact ionization mass spectrometry and intramolecular cyclization in 2-substituted pyrimidin-4(3H)-ones.

Electron impact ionization mass spectrometry indicates that the behavior of W-unsubstituted pyrirnidin-4-ones with CH2-R type substitution at C-2 differs from homologs that are N-substituted and/or 2-aryl- or 2-methyl-substituted. A dominant intramolecular cycliza-tion was found to occur between 3ZV (in agreement with the predominance of the 3NH tautomers) and the ortho positions of the aryl moiety in compounds with a CH2-aryl substitution at C-2. Theoretical calculations with an AMI SCFR method on 2-, 6-, and 2, 6-disubstituted pyrimidin-4-ones support the mass spectrometric observations.

Structure of norbornene-fused 3,1-oxazine double cycloadducts.

Pentacyclic isoxazolines were obtained by the cycloaddition of benzonitrile oxide to norbornene-azetidinone-fused 3,1-oxazines. The constitutions of two of the isomers obtained, and the configurations and conformations of all products, were determined by means of H and C NMR spectroscopy and DNOE experiments.