AN APPROACH TO SYNTHESIS OF DITERPENOID ALKALOIDS. II.
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A series of tropane-3-spiro-4'(5')-imidazolines was synthesized and studied by 1H and 13C NMR spectroscopy, and the crystal structure of 2'-(1H-indol-3-yl)tropane-3-spiro-4'(5')-imidazoline hydrochloride 5(6)f was determined by X-ray diffraction. In CD3OD solution, compounds 5(6)a-f display the same preferred conformation. The pyrrolidine and piperidine rings adopt an envelope conformation flattened at N8 and a distorted chair conformation puckered at N8 and flattened at C3, respectively, with the N-substituent in the equatorial position with respect to the piperidine ring. This conformation is similar to that observed for compound 5(6)f in the solid state. From binding studies on the compounds synthesized, compound 5(6)d demonstrated the ability to efficiently displace the binding of [3H]GR65630 to bovine brain area postrema membranes to an extent comparable to MDL 72222. In the von Bezold-Jarisch reflex, compound 5(6)d was equipotent with metoclopramide. It is, therefore, likely that the imidazoline ring may provide a useful bioisosteric replacement for the carbonyl group in 5-HT3 antagonists.
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Here we report on our studies on combinations of amino acids and copper(I) for catalyzing multicomponent reactions (MCRs). We aimed to prepare both diene and dienophiles simultaneously, under very mild and environmentally friendly conditions, thus giving the constituents for a stereocontrolled Diels-Alder reaction, which in turn yields compounds 4 to 8. A diversity-oriented synthesis of polysubstituted spirotriones 4 to 6 were assembled from simple substrates like 1-(triphenylphosphanylidene)-propan-2-one, two aldehydes, and cyclic-1,3-diketones through Wittig/Knoevenagel/Diels-Alder and aldol/Knoevenagel/Diels-Alder reaction sequences in one pot under stereospecific organocatalysis. Chemical diversity libraries of polysubstituted spirotrione-1,2,3-traizoles 8 were assembled from simple substrates by means of Wittig/Knoevenagel/Diels-Alder/Huisgen cycloaddition reaction sequences in one pot under stereospecific organo/Cu(I) catalysis. Functionalized dispirolactones such as 6 are biologically active antioxidants and radical scavengers, and spirotrione-1,2,3-traizoles 8 have found wide applications in chemistry, biology, and materials science. Experimentally simple and environmentally friendly, organocatalytic, asymmetric four-component Diels-Alder (AFCDA) reactions of 1-(triphenylphosphanylidene)- propan-2-one, two different aldehydes, and cyclic-1,3-diketones produced diastereospecific and highly enantioselective substituted spirotriones 4 by means of a Wittig/Knoevenagel/Diels-Alder reaction sequence in one pot. Additionally we have developed an organocatalytic, asymmetric three-component Michael (ATCM) reaction of 1-(triphenylphosphanylidene)-propan-2-one, aldehyde, and cyclic-1,3-diketones that produced Michael adducts 15, 16 through a Wittig/Michael reaction sequence in a highly enantioselective one-pot process.
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Twenty one evaluable patients with advanced colorectal carcinoma were treated with continuous infusion of spirogermanium at a median daily dose of 150 mg/m2 (range 120-210) for five consecutive days every 14 days. Treatments were accomplished by using outpatient infusion devices. Fifteen patients had not received any prior radiation therapy, immunotherapy, or chemotherapy. Nineteen patients were previously untreated with chemotherapy. Five patients had received prior immunotherapy with copovithane and only two patients had received radiation therapy prior to spirogermanium therapy. None of the patients achieved a complete or partial remission. Minor tumor regressions were observed in two patients, both were less than 12 weeks in duration. The major toxicities included nausea and vomiting and neurologic side effects; however, the toxicity was completely reversible. Spirogermanium is not effective in the treatment of patients with advanced colorectal carcinoma.
Fifty-four evaluable patients with SCLC previously treated with chemotherapy received either N-methylformamide or spirogermanium. There was one partial response to N-methylformamide. The median survival times for patients treated with N-MF and spirogermanium were 11.7 and 12.6 weeks respectively. Five patients treated with N-MF experienced severe toxicity while four patients treated with spirogermanium experienced severe and life-threatening toxicity.
Seventeen patients with advanced colorectal carcinoma were treated with a combination of 5-fluorouracil and spirogermanium, a recently developed azaspiran-germanium compound remarkable for its lack of hematologic, gastrointestinal, renal or hepatic toxicity. Response to treatment and the incidence and severity of toxicity were evaluated. No patient achieved a complete response; there were three partial responses. Toxicity was unexpectedly frequent and severe; one patient was removed from study early due to intractable diarrhea, and there were two toxic deaths, both attributable to neutropenia and sepsis. Significant toxicity occurred in all seventeen patients, including three instances of Grade 3 or 4 hematologic toxicity. Given the low response rate and high incidence of life-threatening toxicity, we do not recommend further evaluation of this schedule of 5-fluorouracil and spirogermanium in the treatment of colorectal carcinoma.
The dioxepinoindole ring found in marcfortine A (1) is unique among natural products. In order to determine the importance of the substitution pattern of the C24-C25 olefin, we synthesized a variety of analogs at these positions. With the exception of compound 5, none of these compounds exhibited any anthelmintic activity.
Spirocyclic tin initiators were prepared by condensation of commercial hydroxyethylated pentaerythritol with Bu(2)Sn(OMe)(2). These tin-containing spirocycles served as initiators for the ring-expansion polymerization of epsilon-caprolactone, beta-D,L-butyrolactone or D,L-lactide. The in situ polycondensation of these expanded spirocycles with terephthaloyl chloride or sebacoyl chloride yielded the desired biodegradable networks with elimination of the Bu(2)Sn group. The segment length (pore size) could be controlled via the monomer-initiator ratio (M/I) of the ring-expansion polymerization. Biodegradable networks were also obtained when Sn-containing spirocyclic polylactones were polycondensed with diphenyl dichlorosilane, benzene phosphonic dichloride, and phenyl phosphoric dichloride.
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