Formal synthesis of schulzeines B and C: A new route to Gurjar's lactams

Described is a formal synthesis of racemic schulzeines B and C that intercepts intermediates developed by Gurjar and co-workers. The synthetic sequence features an annulative coupling of a ketimine and acrylic acid enabling the construction of the benzoquinolizidine nucleus in a highly convergent manner. We also examined a continuous-flow version of the thermal aza-annulation, which proved less practical as compared to the batch processes.     

Infrared Absorption,Nuclear Magnetic Resonance and Electronic Spectra of N-Hydroxyureas and Carbamates

During the course of investigating the anticancer activities of new compounds, we have synthesized a series of novel cyclic N-hydroxyurea derivatives and several carbamate intermediates^1–3. Infrared absorption, nuclear magnetic resonance, and electronic absorption spectra were examined in order to confirm the identities and to study the molecular structure of these compounds.     

INTEGRABLE SYSTEM AND SPACELIKE SURFACES WITH PRESCRIBED MEAN CURVATURE IN MINKOWSKI 3-SPACE

1IntroductionItiswell-knownthattheclassicalWeierstrass-EnneperrepresentationformuladescribeschinalsurfacesinEuclidean3-spaceR3intermsoftheirGaussmapsandauxiliaryholomorphicfunctions[1].Moregenerally,aremarkablerepresentationforlllulahasbeendiscoveredbyKenmotsu[2]forarbitrarysurfaCesinR3withnonvallishingmeancurvature,whichdescribesthesesurfacesintermsoftheirGaussmapsandmeancurvaturefunctions.Recently,Konopelchenko[31rediscoveredthisrepresentationformulaindifferentbutequivalentformillconnect…     

Composition and antimicrobial activity of the leaf and twig oils of Litsea mushaensis and L. linii from Taiwan

The hydrodistilled essential oils of the leaves and twigs of Litsea mushaensis and L. linii were analyzed. Sixty-nine and ninety compounds were identified in the leaf and twig oils, respectively, of L. mushaensis. The main components of the leaf oil were beta-eudesmol (24.2%), tau-cadinol (10.2%), alpha-humulene (10.1%), alpha-pinene (9.7%), and trans-beta-ocimene (6.5%), whereas the main components of the twig oil were trans-beta-ocimene (19.5%), alpha-pinene (12.8%) and cis-beta-ocimene (7.7%). With L. linii, 72 and 78 compounds were respectively identified in the leaf and twig oils. The main components of the leaf oil were beta-selinene (15.7%), alpha-selinene (15.5%), beta-caryophyllene (12.2%), alpha-humulene (7.2%), and delta-cadinene (5.6%), and of the twig oil trans-beta-ocimene (20.8%), beta-selinene (11.4%), alpha-cadinol (6.0%), delta-cadinene (5.8%), tau-cadinol (5.4%) and beta-eudesmol (5.2%). L. mushaensis leaf oil was shown to have excellent antimicrobial and anti-wood-decay fungal activity, superior to the other oils.     

Analysis of protein pathway networks using hybrid properties

Given a protein-forming system, i.e., a system consisting of certain number of different proteins, can it form a biologically meaningful pathway? This is a fundamental problem in systems biology and proteomics. During the past decade, a vast amount of information on different organisms, at both the genetic and metabolic levels, has been accumulated and systematically stored in various specific databases, such as KEGG, ENZYME, BRENDA, EcoCyc and MetaCyc. These data have made it feasible to address such an essential problem. In this paper, we have analyzed known regulatory pathways in humans by extracting different (biological and graphic) features from each of the 17,069 protein-formed systems, of which 169 are positive pathways, i.e., known regulatory pathways taken from KEGG; while 16,900 were negative, i.e., not formed as a biologically meaningful pathway. Each of these protein-forming systems was represented by 352 features, of which 88 are graph features and 264 biological features. To analyze these features, the "Minimum Redundancy Maximum Relevance" and the "Incremental Feature Selection" techniques were utilized to select a set of 22 optimal features to query whether a protein-forming system is able to form a biologically meaningful pathway or not. It was found through cross-validation that the overall success rate thus obtained in identifying the positive pathways was 79.88%. It is anticipated that, this novel approach and encouraging result, although preliminary yet, may stimulate extensive investigations into this important topic.