RESUMEN
An interesting competitive C-C vs. C-O bond coupling reaction on N,3,5-trisubstituted pyridones is reported. These coupling reactions provided selective access to C- or O-ring-fused pyridones, both at the challenging C6-pyridone position. 1,6-C-Annulated pyridones were generally achieved in good yields with excellent chemoselectivity under Pd(0) conditions. On the other hand, full C6-regioselective Csp(2) aryloxylation was achieved under oxidative coupling promoted by silver salts to access 5,6-O-annulated pyridones. Based on various experiments and observations, mechanistic evidence of these competitive reactions was provided and it was proposed that C-O bond formation proceeded through radical cyclization. These processes were performed under mild reaction conditions and offer an efficient and attractive methodology to selectively access a large scope of C-arylated and O-arylated pyridones of biological interest.
Asunto(s)
Carbono/química , Oxígeno/química , Piridonas/química , Espectroscopía de Resonancia Magnética , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
INTRODUCTION: Ever since James Syme described his amputation at the ankle joint, most authors have agreed that Syme's amputation should not be considered for patients with diabetic vascular disease (DVD). The aim of the study was to record our experience with Syme's amputations and to search for any predictive criteria that may enhance successful results. PATIENTS AND METHODS: Seventy patients underwent a Syme amputation between the years 1980 and 2000 in our department, 51 owing to DVD. The other 19 patients had their amputations because of other pathologies. RESULTS: The 19 patients of the non-DVD group showed a success rate of 94.7% (18/19). The overall success rate of the DVD patients was 49% (25/51). When we analysed the DVD group by age, the cut-off point was 65 years old. Patients aged 65 or less had a success rate of 68.2% (15/22), and over the age of 65 years the success rate was only 30.8% (8/26). CONCLUSIONS: Patients with DVD should be considered good candidates for a Syme amputation if they are younger than 65 years old.
Asunto(s)
Amputación Quirúrgica/métodos , Amputados/rehabilitación , Articulación del Tobillo/cirugía , Angiopatías Diabéticas/cirugía , Enfermedades Vasculares Periféricas/cirugía , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Vasculares Periféricas/etiología , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
NaBH(4) reduction of imides 1 and 6a,b,c followed by a pi-cyclization of the resultant N-acyliminium ions, generated in trifluoroacetic acid conditions, afforded two positional isomers, isoindolobenzothiazolinones 4 and 8, respectively. These ring closures proceeded via an intramolecular alpha-amidoalkylation with the classical pi-aromatic or the atypical sulfur atom as an internal nucleophile. A ready access to the related six-membered N,S-heterocyclic compounds such as isoindolobenzothiazinones 20a and 21a is also described. During this reaction, we have shown that omega-carbinol lactam precursor 14a led to endocyclic and exocyclic N-acyliminium ions 18a and 19a in equilibrium via the cyclic aza-sulfonium ion A. The latter furnished the expected products 20a and 21a in good yields. Similarly, different omega-carbinol lactams 14b-e substituted at C-angular position afforded the corresponding isoindolobenzothiazinones 20b-e and 21b-e bearing an angular alkyl, aralkyl, or aryl group. In the case of methyl 14b and benzyl 14e groups, an additional amount of the dehydration products 16b and 31 was isolated. These results indicate that the isomerization-pi-cyclization takes place via the cleavage of the thioether linkage in acidic medium.
RESUMEN
OBJECTIVE: We report a case of slow ascending myelopathy in a patient with ankylosing spondylitis (AS). DESIGN: Case report of a 60-year-old patient suffering from AS, who developed over a period of 39 years a slow ascending myelopathy leading to tetraplegia, squamous cell carcinoma of the bladder and amyloidosis of the small intestine secondary to neuropathic bladder and bowel. SETTING: Department and Outpatient's Department of Neurological Rehabilitation Sheba Medical Center, Tel Hashomer, Israel. SUBJECT: Single patient case report. MAIN OUTCOME MEASURE: Clinical follow-up of the patient between the years 1959 - 1998. RESULTS: Physical examination disclosed deteriorating incomplete tetraplegia with hypotonia and hyporreflexia. Neurogenic bladder and bowel complicated to squamous cell carcinoma and amyloidosis. CONCLUSION: To our knowledge, flaccid tetraplegia associated with AS, has never been reported in the literature. The possibility of vascular compression by the ankylosed spine causing the clinical picture of flaccid tetraplegia in this patient is discussed.