Glycyrrhetinic amides and their cytotoxicity

3-<em>O</em>-Acetyl-glycyrrhetinic amides were prepared, and sulforhodamine B assays investigated their cytotoxicity. Their cytotoxicity strongly depended on the substitution pattern of the respective compounds. Thereby, an ethylenediamine-derived compound <strong>2</strong> performed the best, acting mainly by apoptosis. As far as heterocyclic amides are concerned, ring enlargement and the replacement of the distal nitrogen invariably led to a more or less complete loss of cytotoxic activity. Thus, the presence of a carbonyl function (C-30) seems necessary for providing significant cytotoxicity.

Aortic valve neocuspidalization in paediatric patients with isolated aortic valve disease: early experience

OBJECTIVES There is growing interest in the aortic valve (AV) neocuspidalization technique for the treatment of aortic valve disease (AVD). We report our medium-term results with this procedure performed in a paediatric patient population. METHODS Between July 2016 and May 2020, 22 patients with both congenital and acquired isolated AVD were treated with neocuspidalization. The primary outcome was progression of the preoperatively assessed AVD in the immediate postoperative course and at follow-up. Secondary outcome was freedom from reintervention by material used. Potential predictors of failure were analysed in relation to the primary outcome. RESULTS The median age at operation was 13.9 (interquartile range, 9.8–16.2) years, and the prevailing AV defect was stenosis in 10 cases (45%) and incompetence in 12 (55%). Pre-treated autologous pericardium was used in 13 patients whereas bovine pericardium in 9. Effective treatment of AV stenosis or regurgitation was achieved and remained stable over a median follow-up of 11.3 (4.7–21) months. Three patients required AV replacement at 4.9, 3.5 and 33 months. At follow-up, an upward trend of both median indexed vena contracta jet widths and aortic peak and mean gradients were recorded, the latter associated with a failure to grow the aortic annulus. Predictor of such outcome turned out to be the use of bovine pericardium. A significant inverse linear correlation between AV peak gradient at follow-up and preoperative aortic annular size (P = 0.008) was also demonstrated. CONCLUSIONS The Ozaki procedure is safe and effective in paediatric patients with AV disease. The use of heterologous pericardium should probably be minimized. Moreover, preoperative small aortic annuli should probably be promptly treated by means of an associated ring enlargement procedure.

Two-Carbon Ring-Enlargement of Cyclic 1,3-Diketones to Cyclic 1,5-Diketones

3-Hydroxy-3-vinylcycloalkanones, which were prepared from the corresponding cyclic 1,3-diketones by mono-vinylation, were rearranged to two-carbon ring enlarged cyclic 1,5-diketones by treatment with a catalytic amount of potassium tert-butoxide.

Role of ring-enlargement reactions in the formation of aromatic hydrocarbons

Ring-enlargement reactions can provide a fast route towards the formation of six-membered single-ring or polycyclic aromatic hydrocarbons (PAHs).

Newer Developments in the Synthesis of P-Heterocycles

The P-heterocyclic field forms a special part of organophosphorus chemistry, and is a special discipline within heterocyclic chemistry. The relevant results accumulated in the group of the author of this minireview in last 5 years are summarized. After surveying the conformational situation of cyclic phosphinates, their Microwave (MW)-assisted direct esterification and the T3P®-promoted esterification are discussed. The next chapters describe newer results regarding the interpretation and modelling of the rate enhancing effect of MWs, and on an important, but somewhat neglected field, the hydrolysis of phosphinates. New results on the ring enlargement of 5-membered unsaturated P-heterocycles to 6-ring species, as well as on the synthesis of 7-phosphanorbornene derivatives, and their refunctionalization are also included. Novel findings on the preparation of cyclic amides and imides are also explored. Last but not least, the user-friendly deoxygenations of cyclic phosphine oxides elaborated by us are shown. The reader will be able to discover green chemical considerations and accomplishments throughout the series of organophosphorus transformations reviewed.

Ring Enlargement of Methylcyclopentane over Pt/(HZSM-48+pseudoboehmite) Catalysts

Platinum catalysts loaded on a hybrid support, composed of HZSM-48 and pseudoboehmite, were applied to the synthesis of benzene through methylcyclopentane (MCP) reforming in order to investigate the effect of the addition of pseudoboehmite to Pt/HZSM-48 for ring-enlargement reaction. A total of 0.5 wt% of platinum was impregnated on the hybrid support by using the incipient wetness method. Catalyst characterization was performed with nitrogen sorption, X-ray diffraction, temperature-programmed desorption of NH3, and infrared spectroscopy of adsorbed pyridine. It was found that mesoporous structures were well-developed in Pt/(HZSM-48 + pseudoboehmite) catalyst as a result of the pseudoboehmite addition, of which the average pore size was in the range of 7–8 nm. The presence of pseudoboehmite in the catalyst increases the total amount of acid sites and weakens the acid strength, compared with those of the Pt/HZSM-48 catalyst. Lewis acid sites were more abundant than Brönsted acid sites over the Pt/(HZSM-48+pseudoboehmite) catalysts. It was found that selectivity to the ring-enlargement reaction is dominant over selectivity to the ring-opening reaction over the Pt/(HZSM-48 + pseudoboehmite) catalysts. The benzene yield over Pt/(HZSM-48 + pseudoboehmite, 1:1) catalyst reached 65.1% at 450 °C and 0.3 h−1. As well as being influenced by the mesoporous structure, the higher activity and selectivity in MCP reforming was also determined by appropriate acidity of the Pt/(HZSM-48 + pseudoboehmite) catalysts.