1,721,125 research outputs found
Preparation of 4-(dimethylamino)-3,5-dimethoxybenzaldehyde as intermediate for antibacterials
No full textThe title compd. (I), an intermediate for antibacterial aditoprim, useful in veterinary medicine, is prepd. via bromination or chlorination of 4-(dimethylamino)benzonitrile (II), treatment of the resulting 3,5-dibromo- (III) or -dichloro-4-(methylamino)benzonitrile with alkali methoxide in the presence of Cu and DMF or dimethylacetamide, methylation of the resulting 3,5-dimethoxy-4-(methylamino)benzonitrile (IV), and redn. of the resulting 3,5-dimethoxy-4-(dimethylamino)benzonitrile. II in MeOH was brominated with aq. HBr, the resulting III treated with MeONa/MeOH and CuCl, and the resulting IV methylated with HCO2H/paraformaldehyde followed by redn. with Raney Ni to give I
Blood reinforced by pigments in the reddish stains of the Turin Shroud
No full textSamples from the Turin Shroud (TS) furnished by STERA Inc. have been analyzed and compared with both material coming from the TS and sticky tapes taken from a copy of the TS produced in 1656 and conserved at Palma di Montechiaro, Sicily, Italy. The attention has been focalized to the many reddish particles contained in these samples that appear to be of many types, shape and sizes. Some of them seem to correspond to the so called “sub-micron particles” recognized by W. McCrone in the form of red ochre (iron oxide) and vermillion (mercury sulfide); the others, as described by many researchers of the STuRP like A. Adler and J. Heller, seem typical of blood. After a detailed analysis of these particles by using various types of microscopes and by performing different spectral analyses like Raman and EDX, the results obtained are commented, reaching the conclusion that the analyzed reddish material, corresponding to some TS bloodstain area, contain human blood reinforced with pigments. It can therefore be supposed that the bloodstains, originally composed of blood, have been refreshed by some artist perhaps during the XVII centur
Asymmetric Desymmetrisation of Meso-Norbornene Anhydrides Utilising Methyl Prolinate as a Chiral Reagent
No full textThe reaction between Me S-prolinate and meso-norbornene derived anhydrides was found to give amido-acids with excellent asym. induction. This methodol. provides an inexpensive route for the prepn. of optically pure, polycyclic, highly functionalized starting materials for natural and unnatural product synthesis on a large scale
Development of DNA topoisomerase-related therapeutics: a short perspective of new challenges.
No full textAntitumor agents targeting DNA and DNA-assocd. processes are widely used in the treatment of human cancers and produce significant increases in the survival of patients. DNA topoisomerases remain the most significant target of these cytotoxic drugs and constitute a growing family of nuclear enzymes that regulate DNA topol. during DNA replication and recombination, DNA transcription, chromosome condensation-decondensation and segregation. Major progress has been attained in recent years in the understanding of the structures of these enzymes and their main cellular functions, hopefully providing new opportunities for pharmacol. interventions. New leads and derivs. of known structures have been reported recently, and here they will be discussed highlighting the challenges to find innovative and more effective drugs. Moreover, we will review novel and diverse approaches relevant to the development of new topoisomerase-related therapeutics
Absolute configuration of 2-sec-butyl-4,5-dihydrothiazole in male mouse urine
No full textThe absolute configuration of 2-sec-butyl-4,5-dihydrothiazole (DHT) in urine of adult male mice was determined through chiral
trifluoroacetyl derivative capillary chromatography by comparing the retention time with synthetic standards. (S)-DHT was
extracted from fresh urine, while neither (R)-DHT nor the racemization of (S)-DHT were detected. We can conclude that DHT
in urine possesses the S configuration, although we cannot exclude a minor component in the R configuration. (S)-DHT was
then characterized for binding to the complex of major urinary proteins of male mouse urine (MUP) and for a behavioral
response, the competitive scent marking behavior (countermarking). The binding constant of (S)-DHT to MUP (determined by
competitive displacement) was 8.2 ± 0.6 μM (mean ± SD) and was 10.5 ± 0.6 μM for R-DHT, thus excluding a relevant difference
in binding. (S)-DHT modified countermarking in a peculiar way. Male mice were slow in countermarking urinary spots
streaked 2 days earlier and on top of which (S)-DHT was added shortly before the test. This response was not seen when adding
(S)-DHT to freshly streaked urinary spots or to clean paper. Unlike (S)-DHT, (R)-DHT prompted countermarking rather than
delaying it. We can further conclude that (S)-DHT in male mouse urine is an aversive chemosignal for countermarking
Antracyclines: recent developments in their separation and quantitation
No full textAnthracyclines are among the most widely used anticancer agents. Notwithstanding the large efforts to develop new drugs with a better pharmaceutical profile, daunorubicin, doxorubicin, epirubicin and idarubicin are still the most used in clinical practice. Many efforts are now ongoing to reduce the side effects by using pharmaceutical formulations able to release the drug in the most appropriate way and monitoring the quantity of anthracyclines and their metabolites in the body fluids or tissues frequently and in every patient to maintain the drug concentration within the expected range. This review describes the most recent developments in the separation and quantitation of the above clinically useful drugs, together with their principal metabolites. Some less widely used derivatives will also be considered
Photo-induced spin switching in a modified anthraquinone modulated by DNA binding
No full textAn anthraquinone modified with a nitroxide radical and able to intercalate into DNA has been synthesized to obtain a molecule the spin state of which can be manipulated by visible light and DNA binding. The doublet ground state of the molecule can be photo-switched to either a strongly coupled spin state (quartet + doublet), when isolated, or to an uncoupled spin state (triplet and doublet), when bound to DNA. The different spin state that is obtained upon photoexcitation depends on the intercalation of the quinonic core into double-stranded DNA which changes the conformation of the molecule, thereby altering the exchange interaction between the excited state localized on the quinonic core and the nitroxide radical. The spin state of the system has been investigated using both continuous-wave and time-resolved EPR spectroscopy
Preparation of aloe-emodin derivatives and their use in the treatment of neoplasias
No full textThe invention relates to prepn. of aloe-emodin (AE) derivs. such as I [R = satd. or unsatd. linear or branched aliph. polycarboxylic acid, arylic polycarboxylic acid, amino acid, acetal of an amino sugar, inorg. acid], for their use as anticancer drugs. Thus, reaction between aloe-emodin with Boc-L-Ala-OSu provided II (R = Boc), which upon deprotection and treatment with concd. trifluoroacetic acid, afforded II [R = H.CF3CO2H (III)]. I show a specific cytotoxicity to tumor cells, also of neuroectodermal origin, to which they may in particular act as aloe-emodin prodrugs. Pharmaceutical compns. contg. I may be used in the treatment of neoplasias. It has surprisingly been found that aloe-emodin derivs. in position 3' (bearing either a pos. or neg. charge) exhibit improved soly. properties and, at the same time, in vitro show cytotoxicity to tumor cells, also of neuroectodermal origin. III exhibited cytotoxicity [EC50 = 6.7 μM, EC50 = 6.7 μM, and EC50 = 5 μM against neurolastoma (S-J-R-KP), neurolastoma (IMR-5), and adenocarcinoma (LoVo 109), resp]
Sequence-Selective Recognition of the d(GGCGCC)2 DNA Palindrome by Oligopeptide Derivatives of Mitoxantrone. Enabling for Simultaneous Targeting of the Two Guanine Bases Upstream from the Central Intercalation Site in Both Grooves and along Both Strands
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