Application of a Titanium Screw for the Hemorrhage from the Bone Channel during the Lateral Window Technique: A Technical Note.

Pulsatile and profuse hemorrhage occurred in the lateral window technique for implant placement. The surgery was performed in the dental clinic under local anesthesia. The posterior superior alveolar artery was suspected to be the main feeder. Ordinary methods for hemostasis, such as vasoconstrictor-soaked gauze compression, electrocautery hemostasis, absorbable hemostat packing, and bone wax application, were tried. However, strong pulsatile bleeding could not be controlled at all. Complete hemostasis was hardly expected. The idea came up when the titanium screws came into sight. The sterilized screw was always stocked for bone grafting. After visualizing the bleeding point clearly by suction, and the screw was inserted into the bone channel. The bleeding was completely stopped immediately. It may not be a novel method, but is certainly a reliable application of the screw, which is fundamentally the same as arterial catheter embolization.

Chemical Degradation-Inspired Total Synthesis of the Antibiotic Macrodiolide, Luminamicin.

This article describes the first total synthesis of luminamicin using a strategy combining chemical degradation with synthesis. Chemical degradation studies provided a sense of the inherent reactivity of the natural product, and deconstruction of the molecule gave rise to a key intermediate, which became the target for chemical synthesis. The core structure of the southern part of luminamicin was constructed by a 1,6-oxa-Michael reaction to form an oxa-bridged ring, followed by coupling with a functionalized organolithium species. Modified Shiina macrolactonization conditions forged the strained 10-membered lactone containing a tri-substituted olefin. Diastereoselective α-oxidation of the 10-membered lactone completed the center part to provide the key intermediate. Inspired by the degradation study, an unprecedented enol ether/maleic anhydride moiety was constructed with a one-pot chlorosulfide coupling and thiol ß-elimination sequence. Finally, macrolactonization to the 14-membered ring in the presence of the highly electrophilic maleic anhydride moiety was accomplished using modified Mukaiyama reagents to complete the synthesis of luminamicin.

Synthesis of enantioenriched 2,2-disubstituted pyrrolidines via sequential asymmetric allylic alkylation and ring contraction.

The synthesis of a variety of enantioenriched 2,2-disubstituted pyrrolidines is described. A stereogenic quaternary center is first formed utilizing an asymmetric allylic alkylation reaction of a benzyloxy imide, which can then be reduced to a chiral hydroxamic acid. This compound can then undergo a thermal "Spino" ring contraction to afford a carbamate protected 2,2-disubstituted pyrrolidine stereospecifically. These pyrrolidines can be further advanced to enantioenriched indolizidine compounds. This reaction sequence allows access to new molecules that could be useful in the development of pharmaceutical agents.

Pd-catalyzed Regio- and Stereoselective Hydrostannylation of an Alkyl Ethynyl Ether/One-Pot Stille Coupling Enables the Synthesis of 14-Membered Macrolactone of Luminamicin.

Regio- and stereoselective hydrostannylation of alkyl ethynyl ethers generates alkenyl ethers, which are useful building blocks in organic synthesis. This efficient synthetic method, however, is limited. Here, we report not only an efficient method for a highly regio- and stereoselective Pd-catalyzed hydrostannylation of alkyl ethynyl ethers but also a scalable synthesis and construction of the core framework of luminamicin possessing all functional groups and stereocenters.

Toward the total synthesis of luminamicin; an anaerobic antibiotic: construction of highly functionalized cis-decalin containing a bridged ether moiety.

Synthesis of a cis-decalin moiety, containing an oxa-bridged cis-decalin ring system (11-oxatricyclo(5.3.1.1,703,8)undecane), as a key intermediate of the total synthesis of luminamicin (1) was accomplished. One of the essential steps in our synthetic route is construction of a cis-decaline framework using a one-pot Michael addition-aldol reaction. Additionally, the bridged ether moiety was obtained by an intramolecular 1,6-oxa-Michael reaction of a conjugated aldehyde.

Total Synthesis and Determination of the Absolute Configuration of Naturally Occurring Mangromicin A, with Potent Antitrypanosomal Activity.

An enantioselective total synthesis of (+)-mangromicin A has been accomplished. The tetrahydrofuran ring of mangromicin A, possessing a tetrasubstituted carbon center, was constructed by Mukaiyama-type vinylogous alkylation via a cyclic oxocarbenium intermediate derived from a γ-hydroxy ketone with ideal stereoselectivity, and the 4-hydroxydihydropyrone scaffold was generated via Dieckmann cyclization at a late stage of the total synthesis. The reliable asymmetric synthesis of (+)-mangromicin A has revealed the absolute configuration of naturally occurring mangromicin A.

Z-selective intramolecular Horner-Wadsworth-Emmons reaction for the synthesis of macrocyclic lactones.

When the substrates (ArO)(2)P(O)CH(2)CO(2)---CHO (Ar = Ph, o-t-BuPh) were added to a THF solution containing 3 equiv of NaH at 0 degrees C or NaI-DBU at rt over 1-10 h, the intramolecular Horner-Wadsworth-Emmons reaction proceeded efficiently to give the 12-18-membered-ring lactones in 69-93% yields with 89-100% Z selectivity. On the other hand, (EtO)(2)P(O)CH(2)CO(2)---CHO gave the 13-18-membered-ring lactones in 52-82% yields with 89-99% E selectivity using LiCl-DBU in MeCN or THF.

Anchoring properties of photoaligned azo-dye materials.

The photoinduced alignment of a liquid crystal (LC) on films of azo dyes was studied for the liquid crystal display applications. In order to improve the alignment stability of the photoaligned dye (SD-1), the azo-dye derivative with polymerizable terminal groups was synthesized (SDA-1). The films of SDA-1 exhibit good photoalignment properties and ultraviolet stability after thermal polymerization. We investigated the anchoring coefficient for polar and azimuthal energy for both azo-dyes SD-1 and SDA-1 using a differential method developed by us. The polar and azimuthal anchoring strengths of azo-dye aligning materials are comparable with those of usual polyimide aligning materials. The electro-optic response of a 90 degrees twisted LC cell remains almost the same after heating up to 200 degrees C, i.e., the anchoring energy remains considerably high.