NOPR Collection:

Two novel pentacyclic triterpenes from Calliandra eriophylla (Benth) (Leguminosae)

1999-01-01T00:00:00Z

Title: Two novel pentacyclic triterpenes from Calliandra eriophylla (Benth) (Leguminosae) Authors: Anam, Edet M Abstract: Oven dried ground roots of C. eriophylla has yielded two new triterpenoids. 2β, 3β-dihydroxy-30-al-olean- 12-ene-28-oic acid 1 and 2β, 3β,23-trihydroxy-30-al-olean-12-ene-28-oic acid, 2. Page(s): 119-121

Synthesis of 2-[N-methyl-N-(4-iodoPhenyl) aminomethyl]-1,3,4-oxa-diazole and its use as a protective synthon for indirect iodination of ketosteroids

1999-01-01T00:00:00Z

Title: Synthesis of 2-[N-methyl-N-(4-iodoPhenyl) aminomethyl]-1,3,4-oxa-diazole and its use as a protective synthon for indirect iodination of ketosteroids Authors: Shabsoug, Barakat M; Hassan, Mohamad A Abstract: 2-(N-methyl-N-phenylaminomethyl)-1, 3, 4 oxadiazole can readily be iodinated to 2-[N-methy-N-(4-iodophenyl) aminomethyl] - 1, 3, 4-oxadiazole which in a one-step hydrolysis condensation serves as an indirect prosthetic moiety for iodination / radio iodination of ketosteroids, and other carbonyl containing biomolecules. Page(s): 96-98

Crown humus: Part I-The chemistry of the canopy organic matter of rain forests in Costa Rica

1999-01-01T00:00:00Z

Title: Crown humus: Part I-The chemistry of the canopy organic matter of rain forests in Costa Rica Authors: Ghosal, S; Muruganandam, A V; Chauhan, S; Kawanishi, K; Saiki, K; Nadkarni, N M Abstract: In some tropical rain forests organic matter, derived from epiphytic plants accumulates as heavy mats on tall tree tops (Crown), trunks and branches. Upon microbial and abiotic (chemical, geological) interactions, the canopy organic matter (COM) is transformed into Crown humus. Detailed chemical, chromatographic and spectroscopic analyses of seven COM samples (COM-1 to -7), collected from five different tree tops, and one soil sample collected from the corresponding forest floor (FF-1 ), from Monte Verde Reserve Forest, in Costa Rica, have been carried out in respect of their low M_w organic compounds and the contained humus. The nature and chemical characteristics of these arboreal humic substances are compared with those of their terrestrial and aquatic counterparts. Some striking similarities, particularly in the core structures of fulvic acids (FAs), occurring in three different natural habitats (arboreal, terrestrial and aquatic), are observed. Like those of terrestrial and aquatic –Fas, the molecular architecture of the Crown-FAs constitute metallo-organic complexes of mono-, di- and oligomeric oxygenated dibenzo--pyrones (1-4, 9a, b, 11, Chart 1). However, the ecological and geochemical conditions of the arboreal miniecosystem being different, are reflected in the simpler structures of large variety of its secondary metabolites (Tables I & II ) entrapped in the inner core and outer-surface of the Crown humus. The role of these compounds in the microbial (chemoheterotroph) metabolic sequence enroute to Crown humus is appraised. Page(s): 67-75

Catalytic Cyclocondensation of acetone to isophorone

1999-01-01T00:00:00Z

Title: Catalytic Cyclocondensation of acetone to isophorone Authors: Ramanamurty, K V; Salvapati, G S Abstract: Cyclocondensation of acetone involves aldol condensation leading initially to the primary condensation products (PCP), diacetone alcohol and mesityl oxide, which again react with acetone to form phorone, isophorone, mesitylene, etc. Relative selectivities of chromia, -alumina, magnesia and calcium oxide catalysts have been studied in a flow reactor at 360-520°C. Alumina and magnesia are found to favour isophorone formation at 360°C with 45% selectivity but the selectivity steeply falls with the increase in temperature to 520 °C due to rise in decomposition products. Primary condensation products are formed more with magnesia; selectivity to mesitylene is more with CaO (~66% at 400-480 °C) and Cr₂O₃ (50-55% at 480-520 °C. Page(s): 24-28