The survival impact of preoperative FOLFOX for resectable locally advanced rectal cancer: the R-NAC-01 study.

PURPOSE: In this follow-up of the R-NAC-01 study, we assessed the long-term oncological benefit of four courses of modified leucovorin, 5-fluorouracil (FU), and oxaliplatin (mFOLFOX6) chemotherapy before rectal surgery. METHODS: In this prospective, multicenter study (UMIN 000012559) involving 11 hospitals in Japan, patients with lower rectal cancer underwent four cycles of mFOLFOX6 chemotherapy and subsequent surgery within four to six weeks. The 3-year recurrence-free survival and local recurrence rates were then reported. RESULTS: Of 41 patients (36 males, 5 females; mean age: 60.8 years old) who received 4 courses of chemotherapy, 40 underwent total mesorectal excision, and 1 underwent total pelvic exenteration. R0 resection was achieved in 40 patients, but none showed a pathological complete response. Twenty-nine patients received adjuvant chemotherapy for an average of 4 months. The 3 year recurrence-free survival and local recurrence rates in patients undergoing curable resection were 72.8% and 8.5%, respectively. cStage III patients with adjuvant chemotherapy had a significantly higher 3 year recurrence-free survival than those without adjuvant chemotherapy (76.6 vs. 40.0%, log-rank p = 0.03). CONCLUSION: Four courses of mFOLFOX6 chemotherapy before surgery may be a promising treatment strategy for locally advanced rectal cancer. Adjuvant chemotherapy might be needed for cStage III patients, even after four courses of neoadjuvant mFOLFOX6.

Ring-Opening Metathesis Polymerization of endo- and exo-Norbornene Lactones.

New ester-functionalized bicyclic aliphatic polymers are synthesized through the ring-opening metathesis polymerization (ROMP) of endo- and exo-norbornene lactones (endo-NBL and exo-NBL) and their oxa-norbornene analogue (exo-oxa-NBL) followed by hydrogenation. The polymerizability between endo- and exo-NBLs, and the thermal properties between the six types of polymers before and after hydrogenation are compared and discussed. The ROMP of all three monomers proceeded in a living fashion under optimized conditions, which is confirmed by chain extension experiments. Endo-NBL shows a much lower homo- and copolymerizability than exo-NBL probably owing to six-membered chelation to the Ru center and steric hindrance in the ruthenacyclobutane intermediate. Stereo-block and stereo-gradient copolymers of poly(endo-NBL) and poly(exo-NBL) are also synthesized. The hydrogenation catalyzed by RuHCl(CO)(PPh3 )3 in the mixed solvents of o-xylene and N,N-dimethyl acetamide (DMAc) results in more than 95% conversion. The obtained hydrogenated polymers, H-poly(endo-NBL) and H-poly(exo-NBL), are amorphous, soluble in chlorinated aliphatic solvents, and thermally stable until 400 °C without a weight loss. Their glass transition temperatures are 163 and 131 °C, respectively; the values are appropriate in terms of both thermal stability and processing deformation for the application of transparent resin materials.

N-Heterocyclic Carbene Initiated Anionic Polymerization of (E,E)-Methyl Sorbate and Subsequent Ring-Closing to Cyclic Poly(alkyl sorbate).

A diene-based cyclic polymer has been synthesized by the anionic polymerization of methyl sorbate (MS) by an N-heterocyclic carbene (NHC) in the presence of a bulky aluminum Lewis acid. We first polymerized methyl sorbate (MS) initiated by NHC in N,N-dimethylformamide (DMF) at 25 °C, poly(MS) with a number-average molecular weight (Mn) of 3.5 × 103 (Mw/Mn = 2.1) was obtained with a conversion of 93%. The structure was confirmed by 1H and 13C NMR and IR spectra, which revealed that the propagation proceeded via 1,2-addition as well as 1,4-addition. Although the polymerization did not occur in toluene in the absence of any additive, quantitative monomer consumption was observed in the presence of methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) to afford the poly(MS) with a 1,4-trans structure, 86% of threo diastereoselectivity, and a Mn of 23.0 × 103 with narrow molecular weight distribution (Mw/Mn = 1.17). From the matrix assisted laser desorption/ionization (MALDI-TOF) mass spectra of poly(MS) and the hydrogenated analogue, ring-closing occurred by nucleophilic attack of the anionic propagating center into the adjacent carbon of the α-terminal imidazolimium group to afford cyclic poly(MS). The cyclic formation in the present synthesis system was confirmed by DSC and viscosity measurements.

Thiol-Mediated Controlled Ring-Opening Polymerization of Cysteine-Derived ß-Thiolactone and Unique Features of Product Polythioester.

The controlled ring-opening polymerization of the ß-thiolactone derived from N-Boc cysteine was achieved using N-Boc-L-cysteine methyl ester as the initiator in NMP at room temperature. The propagating end is the thiol group, which attacks the carbonyl to open the monomer ring by the C(═O)-S bond scission. A thiol-ene click reaction demonstrated the utility of the thiol group at the propagating terminal. The block copolymer was efficiently produced by the terminal coupling of the polythioester with the norbornene terminated PEG. As another interesting reaction, the polythioester underwent the main chain transformation to polycysteine through the intramolecular S-to-N acyl migration, triggered by the deprotection of the pendant Boc groups. The polythioester from L-cysteine showed Cotton effects between 200 and 300 nm in the circular dichroism (CD) spectrum. Although the CD pattern resembled that produced by the α-helix of polypeptide, it was ascribable not to the second structure but to the relative orientation of the thioester and carbamate carbonyls in the repeating unit.

Cooperative N-heterocyclic carbene/Brønsted acid catalysis for the tail-to-tail (co)dimerization of methacrylonitrile.

The first tail-to-tail dimerization of methacrylonitrile (MAN) has been realized by the cooperative use of N-heterocyclic carbene (NHC) and Brønsted acid catalysts, producing 2,5-dimethylhex-2-enedinitrile with the E/Z ratio of 24:76. Although the NHC alone was not effective for the catalysis, the addition of alcohols resulted in the significant increase of the dimer yield up to 82% in the presence of 5 mol % NHC. Detailed experimental studies including the ESI-MS analysis of the intermediates, stoichiometric (co)dimerizations, and deuterium-labeling experiments revealed the mechanistic aspects of the proton transfer, isomerization, umpolung, and rate-limiting steps, allowing us to observe several mechanistic differences between the dimerization of MAN and that of methyl methacrylate. The stoichiometric reactions in the presence and absence of an alcohol suggest that the alcohol additives play a role in promoting the intermolecular proton transfers from the deoxy-Breslow intermediate to the regenerated NHC in the second half of the catalytic cycle. In addition, the codimerizations of MAN with n-butyl methacrylate (n-BuMA) have been studied. While the dimerization of n-BuMA was sluggish in the presence of an alcohol, the catalytic activity for the codimerization was enhanced by the cooperative systems.

Helicity Induction in Three π-Conjugated Chromophores by Planar Chirality of Calixamide.

Shall we twist? Three-dimensional arrangement of π-conjugated chromophores with triple-stranded helicity was achieved by using the planar chirality of m-calix[3]amide. Based on spectroscopic data and theoretical calculations, the dynamic and preferred helical characters of bithiophene units embedded in the tubular molecule were elucidated, and the absolute configuration was determined.

Experimental mechanistic studies of the tail-to-tail dimerization of methyl methacrylate catalyzed by N-heterocyclic carbene.

We and others have previously reported the intermolecular umpolung reactions of Michael acceptors catalyzed by an N-heterocyclic carbene (NHC). The representative tail-to-tail dimerization of methyl methacrylate (MMA) has now been intensively investigated, leading to the following conclusions: (1) The catalysis involves the deoxy-Breslow intermediate, which is quite stable and remains active after the catalysis. (2) Addition of the intermediate to MMA and the final catalyst elimination are the rate-limiting steps. Addition of the NHC to MMA and the proton transfers are relatively very rapid. (3) The two alkenyl protons of the first MMA undergo an intermolecular transfer to C3 and C5 of the dimer. (4) The initial proton transfer is intermolecular. (5) Compared with the benzoin condensation, noticeable differences in the kinetics, reversibility, and stability of the intermediates are observed.

Syntheses of aliphatic polycarbonates from 2'-deoxyribonucleosides.

Poly(2'-deoxyadenosine) and poly(thymidine) constructed of carbonate linkages were synthesized by polycondensation between silyl ether and carbonylimidazolide at the 3'- and 5'-positions of the 2'-deoxyribonucleoside monomers. The N-benzoyl-2'-deoxyadenosine monomer afforded the corresponding polycarbonate together with the cyclic oligomers. However, the deprotection of the N-benzoyl group resulted in the scission of the polymer main chain. Thus, the N-unprotected 2'-deoxyadenosine monomers were examined for polycondensation. However, there was involved the undesired reaction between the adenine amino group and the carbonylimidazolide to form the carbamate linkage. In order to exclude this unfavorable reaction, dynamic protection was employed. Strong hydrogen bonding was used in place of the usual covalent bonding for reducing the nucleophilicity of the adenine amino group. Herein, 3',5'-O-diacylthymidines that form the complementary hydrogen bonding with the adenine amino group were added to the polymerization system of the N-unprotected 2'-deoxyadenosine monomer. Consequently, although the oligomers (M(n) = 1000-1500) were produced, the contents of the carbamate group were greatly reduced. The dynamic protection reagents were easily and quantitatively recovered as the MeOH soluble parts from the polymerization mixtures. In the polycondensation of the thymidine monomer, there tended to be involved another unfavorable reaction of carbonate exchange, which consequently formed the irregular carbonate linkages at not only the 3'-5' but also the 3'-3' and 5'-5' positions. Employing the well-designed monomer suppressed the carbonate exchange reaction to produce poly(thymidine) with the almost regular 3'-5'carbonate linkages.

84 dB amplification, 0.46 J in a 10 Hz output diode-pumped Nd:YLF ring amplifier with phase-conjugated wavefront corrector.

A diode-pumped joule class in a 10 Hz output Nd:YLF ring amplifier has been developed. A phase conjugate plate was developed as a wavefront corrector for the residual wavefront distortion of an Nd:YLF rod. We have demonstrated a 0.46 J output of 10 ns pulse duration at 10 Hz repetition rate with 1.5 nJ of input energy. The effective gain of the ring amplifier system was 84.8 dB. To our knowledge, this is the highest magnification with joule-level output energy in a single-stage amplifier system that has ever been built. As a preamplifier system, this system contributed a demonstration of 21.3 J in a 10 Hz output diode-pumped Nd:glass zigzag slab laser system with a stimulated Brillouin scattering- phase conjugation mirror. We describe a robust and effective method of wavefront correction for high-energy laser systems.

A rare case of cavernous hemangioma accompanied with diffuse hepatic hemangiomatosis.

BACKGROUND: Hepatic cavernous hemangioma (CH) is the most common hepatic benign tumor. Most cases are solitary, asymptomatic, and found incidentally. In symptomatic cases with rapidly growing tumors and coagulopathy, surgical treatment is considered. In rare cases, diffuse hepatic hemangiomatosis (DHH) is reported as a comorbidity. The etiology of DHH is unknown. CASE PRESENTATION: A 29-year-old female patient had a history of endometriosis treated with oral contraceptives. Hepatic CH was incidentally detected in the segment IVa of the liver according to the Couinaud classification. Follow-up computed tomography (CT) and ultrasound sonography showed the growth of the lesion and formation of multiple new lesions near the first. Enhanced CT and magnetic resonance imaging (MRI) revealed that the new lesions were different from CH. Although oral contraceptives were stopped, all lesions grew in size. Malignancy and possibility of rupture of these tumors were considered due to the clinical course, and we opted for surgical removal of the tumors. Left liver lobectomy and cholecystectomy were performed. Surgical findings were small red spot spreading and a mass in segment IV of the liver. Pathological examination revealed a circumscribed sponge-like tumor with diffuse irregular extension to the adjacent area. Both of the lesions consisted of blood-filled dilated vascular spaces lined by flat endothelium without atypia. The diagnosis was hepatic CH with DHH. The patient was discharged on postoperative day 12 uneventfully. CONCLUSION: We report the successful resection of CH with DHH. The case findings suggest a relationship between oral contraceptive use and enlargement of CH and DHH. Although DHH has been poorly understood, a few previously published cases reported DHH occurrence in patients using oral contraceptives. In such cases, the decision to perform surgical resection should be made after careful examination.

N-Heterocyclic carbene-mediated redox condensation of alcohols.

N-Heterocyclic carbenes (NHCs) with a variety of oxidants promote the Mitsunobu-type coupling reactions of alcohols with phenols, carboxylic acids, and phthalimide. Experiments using a chiral alcohol indicate that these reactions proceed via SN1 or SN2 pathways depending on the polarity of the used solvents. The NHCs are consumed as reducing reagents to form their oxides as readily separable byproducts.

[Clinical evaluation of chemotherapy with irinotecan (CPT-11), l-leucovorin (l-LV), 5-fluorouracil (5-FU), and UFT for metastatic or recurrent colorectal cancer].

A clinical study has been conducted since August 2001 to investigate whether chemotherapy with CPT-11/l-LV/ 5-FU/UFT could be an effective regimen for advanced or recurrent colorectal cancer. The chemotherapy consisted of CPT-11 30 mg/m2 iv, as a 120-minute infusion, followed by l-LV 30 mg/m2, as a 60-minute infusion, followed by 5-FU 300 mg/m2, as a 120-minute infusion. This treatment was administered weekly for 6 weeks followed by a 2-week rest period and repeated every 8 weeks. UFT (250 mg/m2/day) was orally administered daily. All patients were evaluable for efficacy, 2 CR, 5 PR, 3 SD and 7 PD. The overall response rate was 41.1% with a median time to progression of 7.1 months and a median survival time of 12.0 months. No grade 3/4 toxicities were observed. The present study suggests that combination chemotherapy with CPT-11, l-LV, 5-FU, and UFT is well tolerated and might be a promising regimen for advanced or recurrent colorectal cancer.

Transfer hydrogenation promoted by N-heterocyclic carbene and water.

N-Heterocyclic carbenes (NHCs) promote the transfer hydrogenation of various activated C=C, C=N, and N=N bonds with water as the proton source. The NHCs act as reducing reagents to be converted into their oxides. A detailed reaction mechanism is proposed on the basis of deuterium-labeling experiments.

Diastereoselective cyclization of an aminobenzoic acid derivative and chiroptical properties of triple-stranded helical bis(phenylethynyl)benzene.

The diastereoselective cyclization of 2,5-dibromo-4-hexylaminobenzoic acid was achieved by the microwave-assisted condensation using SiCl4. Moreover, the triple-stranded helical structure of bis(phenylethynyl)benzene units embedded in the cyclic tri(benzamide) scaffold was obtained by a Sonogashira-Hagihara coupling reaction. Two optically active enantiomers that do not racemize even at the elevated temperature were separated by chiral HPLC. The chiral helical topology was revealed by the spectroscopic data and theoretical calculation.

Solid-State Polycondensation via Ionic-to-Covalent Bond Transformation to Control Polymer Structure: Preparation of Porphyrin-Based Ladder Polymer.

The controlled formation and the regular arrangement of polymer chains have been performed by novel solid-state polycondensation including the ionic-to-covalent bond transformation in the ionic molecular crystals. The combination of the tetra-anion and -cation of tetraphenylporphyrin derivatives, tetrakis(benzylpyridinium carboxylate), was found to form layered crystal structures and underwent thermal solid-state polycondensation, thus, releasing the pyridine and forming the benzyl ester linkages. Powder X-ray diffraction, when compared to the monomer crystal structure data, suggested that the ladder polymer was produced with a layered structure.

[A case of gastric cancer associated with synchronous liver metastasis successfully treated with combination therapy of systemic and hepatic arterial infusion chemotherapy].

A 56-year-old man who underwent distal gastrectomy at another hospital was admitted to our hospital because of advanced gastric cancer with synchronous liver metastasis. As we considered that the metastatic liver tumor was unresectable one, an intra-arterial catheter was inserted and weekly chemotherapy including methotrexate (MTX) (intra-venous) and 5-fluorouracil (5-FU) (intra-arterial) was started. The metastatic liver tumor was gradually reduced and resulted in partial response (PR) after 12 courses. Eight months later, the size of the metastatic liver tumor increased and lung metastasis occurred, so we started a new regimen of chemotherapy using CPT-11 (intra-venous) and CDDP (intra-arterial). After 4 courses of this regimen, we gained PR both in the metastatic liver and lung tumor. This case indicates that the combination therapy of systemic and hepatic arterial infusion chemotherapy is a treatment option in cases of advanced gastric cancer with liver metastasis.

N-Heterocyclic carbene-catalyzed cyclotetramerization of acrylates.

N-Heterocyclic carbenes (NHCs) were found to catalyze the unprecedented cyclotetramerization of acrylates, producing the trisubstituted cyclopentenones in moderate yields. The proton or deuterium adducts of the deoxy-Breslow intermediate derived from NHC and two molecules of methyl acrylate were obtained. A reaction mechanism involving the new umpolung/cyclization sequence is proposed.

Organocatalytic tail-to-tail dimerization of olefin: umpolung of methyl methacrylate mediated by N-heterocyclic carbene.

Highly selective tail-to-tail dimerization of methyl methacrylate has been realized by an N-heterocyclic carbene catalyst, giving dimethyl 2,5-dimethyl-2-hexenedioate with an E/Z ratio of 95:5 in 86% isolated yield. The umpolung mechanism is proposed on the basis of interception of the intermediates using ESI-MS analyses and deuterium-labeling experiments.

Formation of alternating copolymers via spontaneous copolymerization of 1,3-dehydroadamantane with electron-deficient vinyl monomers.

Copolymerizations of 1,3-dehydroadamantane, 1, and various vinyl monomers were carried out in THF at room temperature. On mixing 1 with electron-deficient vinyl monomers, such as acrylonitrile and methyl acrylate, in the absence of any initiator, the copolymerization spontaneously proceeded to give alternating copolymers in 28-88% yield. By contrast, no reaction of 1 occurred at all when isobutyl vinyl ether or styrene was mixed under similar conditions. These contrastive results indicate the high electron density of a central sigma-bond in a strained [3.3.1]propellane derivative, 1. Alternating sequences of the resulting copolymers were characterized by NMR and MALDI-TOF-MS measurements. DSC and TGA measurements revealed the high thermal stability of the alternating copolymers containing bulky, stiff, and strain-free adamantane skeletons.