(R)-Metacycloprodigiosin-HCl: Chiroptical properties and structure.

(R)-Metacycloprodigiosin can exist in three different tautomeric forms, each with hydrogens at C9' and C12 in syn or anti orientation. With the addition of HCl, this structural diversity reduces to syn-(R)-metacycloprodigiosin-HCl (1a) and anti-(R)-metacycloprodigiosin-HCl (1b), each with multiple conformers. Energetics and chiroptical properties, namely, electronic circular dichroism (ECD) and specific optical rotation (SOR), of (R)-metacycloprodigiosin-HCl have been investigated at B3LYP/6-311++G(2d,2p) level. The experimental ECD spectra of (R)-metacycloprodigiosin-HCl have also been measured. Calculations indicated that the lowest energy conformer of 1b is approximately 2.7 kcal/mol lower in energy than that of 1a, and the energy barrier for anti to syn conversion is approximately 13 kcal/mol. The population weighted calculated SORs of 1a and 1b are, respectively, positive and negative. The respective calculated ECD spectra of these pseudoenantiomers show an almost mirror image relationship between them. The experimental SOR and ECD compare well with those predicted for 1b. Thus, 1b is expected to be predominant, a situation confirmed also by nuclear Overhauser effect (NOE) data, with a similar conclusion reached for prodigiosin R1.

NavMol 3.0: enabling the representation of metabolic reactions by blind users.

Summary: The representation of metabolic reactions strongly relies on visualization, which is a major barrier for blind users. The NavMol software renders the communication and interpretation of molecular structures and reactions accessible by integrating chemoinformatics and assistive technology. NavMol 3.0 provides a molecular editor for metabolic reactions. The user can start with templates of reactions and build from such cores. Atom-to-atom mapping enables changes in the reactants to be reflected in the products (and vice-versa) and the reaction centres to be automatically identified. Blind users can easily interact with the software using the keyboard and text-to-speech technology. Availability and implementation: NavMol 3.0 is free and open source under the GNU general public license (GPLv3), and can be downloaded at http://sourceforge.net/projects/navmol as a JAR file. Contact: joao@airesdesousa.com.

Chiroptical properties of streptorubin B: the synergy between theory and experiment.

Analysis of the calculated and measured optical rotation (OR) together with other calculated chiroptical properties such as electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) of the prodigiosin alkaloid streptorubin B shows that these are dominated by the pseudoenantiomeric atropisomers anti-(S)-streptorubin B (1A) and syn-(S)-streptorubin (1B). Atropisomerism is a dynamic phenomenon with a potentially nonequilibrium population of isomers, and accordingly the measured chiroptical responses may vary with time, concentration, temperature, and the anion of the salts used. Streptorubin also has the potential to form stacked homodimers for which the optical rotations measured at 589 nm can vary greatly due to the presence of ECD-active electronic transitions in this region.

N-heteroatom substitution effect in 3-aza-cope rearrangements.

BACKGROUND: The nature of the heteroatom substitution in the nitrogen of a 3-aza-Cope system is explored. RESULTS: While N-propargyl isoxazolin-5-ones suffer 3-aza-Cope rearrangements at 60°C, the corresponding N-propargyl pyrazol-5-ones need a higher temperature of 180°C for the equivalent reaction. When the propargyl group is substituted by an allyl group, the temperature of the rearrangement for both type of compounds is less affected by the nature of the heteroatom present. Treatment with a base, such as ethoxide, facilitates the rearrangement, and in the case of isoxazol-5- ones other ring opening reactions take precedence, involving N-O ring cleavage of the 5-membered ring. However when base-catalysed decomposition is prevented by substituents, products arising from a room temperature aza-Cope rearrangement are isolated. A possible mechanistic pathway based on free energies derived from density functional calculations involving cyclic intermediates is proposed. CONCLUSIONS: The nature of the heteroatom substitution in the nitrogen of a 3-aza-Cope system leads to a remarkable difference in the energy of activation of the reaction.

Studies in sigmatropic rearrangements of N-prenylindole derivatives--a formal enantiomerically pure synthesis of tryprostatin B.

Rearrangement of N(a)-prenyl-N(b)-acetyltryptamine, induced by BF3.Et2O at low temperature, leads to a 2-prenyl derivative, and thence to the tricyclic tryptamine 7 and the indoline 8. Similarly, N(a)-prenyl-N(b)-phthaloyl-l-tryptophan methyl ester furnished the corresponding 2-prenyl derivative 16, a known advanced precursor of tryprostatin B. Density functional (B3LYP) calculations for the putative rearrangement transition state for N-prenylskatole show that prior coordination of BF3 to the indolic nitrogen changes the character of the subsequent sigmatropic pericyclic shifts from being entirely covalent to acquiring a significant degree of ionic character. The shifting prenyl group favours the endo over the exo mode of the transition state by 4.1 kcal mol(-1).

Studies in 3-oxy-assisted 3-aza cope rearrangements.

On thermolysis appropriately substituted N-silyloxy-N-allyl enamines undergo smooth 3,3-sigmatropic rearrangments to the corresponding N-silyloxy imino ethers.

Edema agudo pulmonar fatal pós transplante autólogo de medula óssea com célula progenitora periférica condicionado com o protocolo BEAM / Fatal acute lung edema after autologous bone marrow transplantation with peripherical steem cell conditioning BEAM protocol

Este relato apresenta um caso de paciente jovem com linfoma näo Hodgkin refratário que apresentou um edema pulmonar agudo fatal após transplante autólogo de células-tronco periféricas. Embora a causa exata do mecanismo do evento seja desconhecida, o texto discute todas as possibilidades, incluindo anafilaxia ao dimetilsulfoxido e disfunçäo cardíaca ventricular transitória secundária ao regime de condicionamento.

Tratamento ambulatorial com 2-clorodeoxiadenosina para doenças linfoproliferativas / Treatment of lymphoproliferatives syndromes and indolent lymphomas by 2-clorodexiadenosina in outpatient reginer

O presente estudo trata da experiência clínica do uso do 2-clorodeoxiadenosina no tratamento da tricoleucemia, síndromes linfoproliferativas e linfomas indolentes. O modo de administraçäo usado em todos os casos exceto dois, foi o da infusäo endovenosa diária por 2 horas, durante cinco dias, com ciclos mensais, num esquema ambulatorial. Dos sete casos de tricoleucemia, tratados com um único ciclo, todos tiveram regressäo da esplenomegalia e 5/7 normalizaram o hemograma. Após um segmento de 2-14 meses, todos os pacientes permaneceram com a doença controlada. Foram tratados sete casos com leucemia linfóide crônica refratária à quimioterapia oral bem como a um esquema de poliquimioterapia endovenosa. Em quatro casos houve uma remissäo parcial, mantida por 3-13 meses.Três pacientes que foram resistentes ao tratamento morreram por infecçäo. Os dois casos de leucemia pró-linfocítica receberam dois e três ciclos respectivamente, com controle da doença por 15 e seis meses respectivamente. Todos estes achados bem como uma observaçäo preliminar com resposta em dois pacientes com linfomas indolentes confirmam os dados da literatura de que o 2-CdA é um quimioterápico com boa açäo em síndromes linfoproliferativas em linfomas indolentes. Sua administraçäo é segura no regime de administraçäo usado, o que torna seu uso mais barato e prático.